Chondromalacia of the knee: evaluation with a fat-suppression three-dimensional SPGR imaging after intravenous contrast injection.

PubMed

Suh, J S; Cho, J H; Shin, K H; Kim, S J

1996-01-01

Twenty-one MRI studies with a fat-suppression three-dimensional spoiled gradient-recalled echo in a steady state (3D SPGR) pulse sequence after intravenous contrast injection were evaluated to assess the accuracy in depicting chondromalacia of the knee. On the basis of MR images, chondromalacia and its grade were determined in each of five articular cartilage regions (total, 105 regions) and then the results were compared to arthroscopic findings. The sensitivity, specificity, and accuracy of MRI were 70%, 99%, and 93%, respectively. MR images depicted 7 of 11 lesions of arthroscopic grade 1 or 2 chondromalacia, and seven of nine lesions of arthroscopic grade 3 or 4 chondromalacia. The cartilage abnormalities in all cases appeared as focal lesions with high signal intensity. Intravenous contrast-injection, fat-suppression 3D SPGR imaging showed high specificity in excluding cartilage abnormalities and may be considered as an alternative to intra-articular MR arthrography when chondromalacia is suspected.

Enhanced neural function in highly aberrated eyes following perceptual learning with adaptive optics.

PubMed

Sabesan, Ramkumar; Barbot, Antoine; Yoon, Geunyoung

2017-03-01

Highly aberrated keratoconic (KC) eyes do not elicit the expected visual advantage from customized optical corrections. This is attributed to the neural insensitivity arising from chronic visual experience with poor retinal image quality, dominated by low spatial frequencies. The goal of this study was to investigate if targeted perceptual learning with adaptive optics (AO) can stimulate neural plasticity in these highly aberrated eyes. The worse eye of 2 KC subjects was trained in a contrast threshold test under AO correction. Prior to training, tumbling 'E' visual acuity and contrast sensitivity at 4, 8, 12, 16, 20, 24 and 28 c/deg were measured in both the trained and untrained eyes of each subject with their routine prescription and with AO correction for a 6mm pupil. The high spatial frequency requiring 50% contrast for detection with AO correction was picked as the training frequency. Subjects were required to train on a contrast detection test with AO correction for 1h for 5 consecutive days. During each training session, threshold contrast measurement at the training frequency with AO was conducted. Pre-training measures were repeated after the 5 training sessions in both eyes (i.e., post-training). After training, contrast sensitivity under AO correction improved on average across spatial frequency by a factor of 1.91 (range: 1.77-2.04) and 1.75 (1.22-2.34) for the two subjects. This improvement in contrast sensitivity transferred to visual acuity with the two subjects improving by 1.5 and 1.3 lines respectively with AO following training. One of the two subjects denoted an interocular transfer of training and an improvement in performance with their routine prescription post-training. This training-induced visual benefit demonstrates the potential of AO as a tool for neural rehabilitation in patients with abnormal corneas. Moreover, it reveals a sufficient degree of neural plasticity in normally developed adults who have a long history of abnormal visual experience due to optical imperfections. Copyright © 2016 Elsevier Ltd. All rights reserved.

Habituation and sensitization in primary headaches

PubMed Central

2013-01-01

The phenomena of habituation and sensitization are considered most useful for studying the neuronal substrates of information processing in the CNS. Both were studied in primary headaches, that are functional disorders of the brain characterized by an abnormal responsivity to any kind of incoming innocuous or painful stimuli and it’s cycling pattern over time (interictal, pre-ictal, ictal). The present review summarizes available data on stimulus responsivity in primary headaches obtained with clinical neurophysiology. In migraine, the majority of electrophysiological studies between attacks have shown that, for a number of different sensory modalities, the brain is characterised by a lack of habituation of evoked responses to repeated stimuli. This abnormal processing of the incoming information reaches its maximum a few days before the beginning of an attack, and normalizes during the attack, at a time when sensitization may also manifest itself. An abnormal rhythmic activity between thalamus and cortex, namely thalamocortical dysrhythmia, may be the pathophysiological mechanism subtending abnormal information processing in migraine. In tension-type headache (TTH), only few signs of deficient habituation were observed only in subgroups of patients. By contrast, using grand-average responses indirect evidence for sensitization has been found in chronic TTH with increased nociceptive specific reflexes and evoked potentials. Generalized increased sensitivity to pain (lower thresholds and increased pain rating) and a dysfunction in supraspinal descending pain control systems may contribute to the development and/or maintenance of central sensitization in chronic TTH. Cluster headache patients are chrarcterized during the bout and on the headache side by a pronounced lack of habituation of the brainstem blink reflex and a general sensitization of pain processing. A better insight into the nature of these ictal/interictal electrophysiological dysfunctions in primary headaches paves the way for novel therapeutic targets and may allow a better understanding of the mode of action of available therapies. PMID:23899115

Application of Optical Coherence Tomography and Contrast Sensitivity Test for Observing Fundus Changes of Patients With Pregnancy-Induced Hypertension Syndrome.

PubMed

Wang, Zhixue; Zou, Yuanyuan; Li, Wenying; Wang, Xueyan; Zhang, Min; Wang, Wenying

2015-11-01

This study was aimed to investigate the fundus changes of patients with pregnancy-induced hypertension syndrome (PIHS) using optical coherence tomography (OCT) technology and contrast sensitivity (CS) tests.Ninety-eight patients with PIHS underwent routine eye examinations including vision correction, fundus examination, OCT, and CS tests. The CS test was performed at low, medium, and high frequency, respectively. Moreover, the difference in CS tests between 2 groups was analyzed by independent-samples T test. The Kruskal-Wallis rank sum test and linear regression model were used to detect the correlation of OCT with CS, respectively. Meanwhile Satterthwaite approximate T test was adopted for pairwise comparisons after nonparametric analysis of variance.The OCT test revealed that 56.76% of the examined eyes showed shallow retinal detachment in the macula lutea and around the optic disk. The differences in CS at each spatial frequency between the case and control group were statistically significant (P < 0.01). Besides, OCT manifestations were associated with CS at each spacial frequency including 1.5, 3, 6, 12, and 18 frequency (P < 0.01). And patients with abnormal manifestations of OCT showed lower CS at each spacial frequency than those without abnormal OCT manifestations. What's more the OCT manifestation 1 showed the greatest impact on CS at each spacial frequency.The results showed that abnormal OCT manifestations were correlated with CS in PIHS. OCT and CS tests might be valuable methods in observing fundus changes for PIHS patients.

Dysphagia risk assessment in acute left-hemispheric middle cerebral artery stroke.

PubMed

Somasundaram, Sriramya; Henke, Christian; Neumann-Haefelin, Tobias; Isenmann, Stefan; Hattingen, Elke; Lorenz, Matthias W; Singer, Oliver C

2014-01-01

Bedside evaluation of dysphagia may be challenging in left middle cerebral artery (MCA) stroke due to frequently existing aphasia. Here we analyse the predictive value of common bedside screening tests and of two items of cortical dysfunction, aphasia and buccofacial apraxia (BFA), for the detection of dysphagia. We prospectively examined 67 consecutive patients with clinical and imaging evidence of acute (<72 h) left MCA stroke. Dysphonia, dysarthria, abnormal volitional cough and abnormal gag reflex were assessed followed by a standardized 50-ml water-swallowing test determining the symptoms cough and voice change after swallow. Aphasia and BFA were assessed according to defined criteria. Fibre-optic endoscopic evaluation of swallowing (FEES) was performed for validation of dysphagia. 41 (61%) patients had FEES-proven dysphagia. Abnormal gag reflex, abnormal volitional cough, cough after swallow, aphasia and BFA were significantly more frequent in dysphagic as compared to non-dysphagic patients, while dysphonia, dysarthria and voice change after swallow were not. Aphasia and BFA had the highest sensitivity (97 and 78%, respectively) and high negative predictive values (89 and 68%, respectively) for dysphagia. Multivariate regression analysis did not identify an independent predictor of dysphagia. In left MCA stroke, the sensitivity and specificity of common bedside dysphagia screening methods are low. In contrast, aphasia and BFA have a high sensitivity and high negative predictive power, presumably due to the neuro-anatomical overlap between cortical regions involved in swallowing, speech production, imitation and voluntary movement control. © 2014 S. Karger AG, Basel.

Multifocal visual evoked potentials reveal normal optic nerve projections in human carriers of oculocutaneous albinism type 1a.

PubMed

Hoffmann, Michael B; Wolynski, Barbara; Meltendorf, Synke; Behrens-Baumann, Wolfgang; Käsmann-Kellner, Barbara

2008-06-01

In albinism, part of the temporal retina projects abnormally to the contralateral hemisphere. A residual misprojection is also evident in feline carriers that are heterozygous for tyrosinase-related albinism. This study was conducted to test whether such residual abnormalities can also be identified in human carriers of oculocutaneous tyrosinase-related albinism (OCA1a). In eight carriers heterozygous for OCA1a and in eight age- and sex-matched control subjects, monocular pattern-reversal and -onset multifocal visual evoked potentials (mfVEPs) were recorded at 60 locations comprising a visual field of 44 degrees diameter (VERIS 5.01; EDI, San Mateo, CA). For each eye and each stimulus location, interhemispheric difference potentials were calculated and correlated with each other, to assess the lateralization of the responses: positive and negative correlations indicate lateralizations on the same or opposite hemispheres, respectively. Misrouted optic nerves are expected to yield negative interocular correlations. The analysis also allowed for the assessment of the sensitivity and specificity of the detection of projection abnormalities. No significant differences were obtained for the distributions of the interocular correlation coefficients of controls and carriers. Consequently, no local representation abnormalities were observed in the group of OCA1a carriers. For pattern-reversal and -onset stimulation, an assessment of the control data yielded similar specificity (97.9% and 94.6%) and sensitivity (74.4% and 74.8%) estimates for the detection of projection abnormalities. The absence of evidence for projection abnormalities in human OCA1a carriers contrasts with the previously reported evidence for abnormalities in cat-carriers of tyrosinase-related albinism. This discrepancy suggests that animal models of albinism may not provide a match to human albinism.

Application of Optical Coherence Tomography and Contrast Sensitivity Test for Observing Fundus Changes of Patients With Pregnancy-Induced Hypertension Syndrome

PubMed Central

Wang, Zhixue; Zou, Yuanyuan; Li, Wenying; Wang, Xueyan; Zhang, Min; Wang, Wenying

2015-01-01

Abstract This study was aimed to investigate the fundus changes of patients with pregnancy-induced hypertension syndrome (PIHS) using optical coherence tomography (OCT) technology and contrast sensitivity (CS) tests. Ninety-eight patients with PIHS underwent routine eye examinations including vision correction, fundus examination, OCT, and CS tests. The CS test was performed at low, medium, and high frequency, respectively. Moreover, the difference in CS tests between 2 groups was analyzed by independent-samples T test. The Kruskal–Wallis rank sum test and linear regression model were used to detect the correlation of OCT with CS, respectively. Meanwhile Satterthwaite approximate T test was adopted for pairwise comparisons after nonparametric analysis of variance. The OCT test revealed that 56.76% of the examined eyes showed shallow retinal detachment in the macula lutea and around the optic disk. The differences in CS at each spatial frequency between the case and control group were statistically significant (P < 0.01). Besides, OCT manifestations were associated with CS at each spacial frequency including 1.5, 3, 6, 12, and 18 frequency (P < 0.01). And patients with abnormal manifestations of OCT showed lower CS at each spacial frequency than those without abnormal OCT manifestations. What's more the OCT manifestation 1 showed the greatest impact on CS at each spacial frequency. The results showed that abnormal OCT manifestations were correlated with CS in PIHS. OCT and CS tests might be valuable methods in observing fundus changes for PIHS patients. PMID:26554764

Keratosis reduces sensitivity of anal cytology in detecting anal intraepithelial neoplasia.

PubMed

ElNaggar, Adam C; Santoso, Joseph T; Xie, Huiwen Bill

2012-02-01

To identify factors that may contribute to poor sensitivity of anal cytology in contrast to the sensitivity of anoscopy in heterosexual women. We analyzed 324 patients with biopsy confirmed diagnosis of genital intraepithelial neoplasia (either vulva, vaginal, or cervical) from 2006 to 2011 who underwent both anal cytology and anoscopy. Cytology, anoscopy, and biopsy results were recorded. Biopsy specimens underwent independent analysis for quality of specimen. Also, biopsy specimens were analyzed for characteristics that may contribute to correlation, or lack thereof, between anal cytology and anoscopic directed biopsy. 133 (41%) patients had abnormal anoscopy and underwent directed biopsy. 120 patients with normal anal cytology had anoscopy directed biopsies, resulting in 58 cases of AIN (sensitivity 9.4%; 0.039-0.199). This cohort was noted to have extensive keratosis covering the entire dysplastic anal lesion. 18 patients yielded abnormal anal cytology. Of these patients, 13 had anoscopic directed biopsies revealing 6 with AIN and absent keratosis (specificity 88.6%; 0.78-0.95). The κ statistic for anal cytology and anoscopy was -0.0213 (95% CI=-0.128-0.086). Keratosis reduces the sensitivity of anal cytology. Furthermore, anal cytology poorly correlates with anoscopy in the detection of AIN (κ statistic=-0.0213). Copyright © 2011 Elsevier Inc. All rights reserved.

Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis.

PubMed

Behbehani, Raed; Ahmed, Samar; Al-Hashel, Jasem; Rousseff, Rossen T; Alroughani, Raed

2017-02-01

Visual evoked potentials and spectral-domain optical coherence tomography are common ancillary studies that assess the visual pathways from a functional and structural aspect, respectively. To compare prevalence of abnormalities of Visual evoked potentials (VEP) and spectral-domain optical coherence tomography (SDOCT) in patients with relapsing remitting multiple sclerosis (RRMS). A cross-sectional study of 100 eyes with disease duration of less than 5 years since the diagnosis. Correlation between retinal nerve fiber layer and ganglion-cell/inner plexiform layer with pattern-reversal visual evoked potentials amplitude and latency and contrast sensitivity was performed. The prevalence of abnormalities in pattern-reversal visual VEP was 56% while that of SOCT was 48% in all eyes. There was significant negative correlations between the average RNFL (r=-0.34, p=0.001) and GCIPL (r=-0.39, p<0.001) with VEP latency. In eyes with prior optic neuritis, a significant negative correlation was seen between average RNFL (r=-0.33, p=0.037) and GCIPL (r=-0.40, p=0.010) with VEP latency. We have found higher prevalence of VEP abnormalities than SCOCT in early relapsing-remitting multiple sclerosis. This suggests that VEP has a higher sensitivity for detecting lesions of the visual pathway in patients with early RRMS. Copyright © 2016 Elsevier B.V. All rights reserved.

[Efficiency of saline contrast hysterosonography for evaluating the uterine cavity].

PubMed

de Kroon, C D; Jansen, F W; Trimbos, J B

2003-08-09

Diagnostic hysteroscopy is the standard investigation performed in the case of abnormal vaginal blood loss. More recently there has been increasing interest for minimal invasive saline contrast hysterosonography (SCHS) as this technique is less painful and less expensive. SCHS is indicated in case of abnormal uterine bleeding (premenopausal and postmenopausal), bleeding while using tamoxifen, suspicion of a congenital uterine abnormality and Asherman's syndrome. As well as intracavity abnormalities (polyps and myomas) SCHS can also be used to evaluate the intramural extension of myomas, which is necessary to assess whether hysteroscopic resection is possible. The sensitivity and specificity of SCHS for demonstrating intracavity abnormalities (with a prevalence of 54%) are 94% (95%-CI; 91-97) and 89% (95%-CI: 85-94) respectively. The positive and negative predictive values are 91% (95%-CI: 87-95) and 92% (95%-CI: 89-97) respectively. SCHS has a short learning curve and can be performed in an outpatient setting. SCHS fails more frequently in postmenopausal women than premenopausal women (12.5% vs. 4.7%; p = 0.03). The chance of a non-conclusive SCHS is 7.6% and is higher if the uterine volume is greater than 600 cm3 (relative risk: 2.63; 95%-CI: 1.05-6.60) and if two or more myomas are present: (RR 2.65; 95%-CI: 1.16-6.10). SCHS is 2 to 9 times cheaper than diagnostic hysteroscopy. It can replace 84% of the diagnostic hysteroscopies. SCHS, in combination with endometrial sampling, whenever indicated, might be able to replace diagnostic hysteroscopy as gold standard in the evaluation of the uterine cavity.

Performance evaluation of a dynamic telepathology system (Panoptiq™) in the morphologic assessment of peripheral blood film abnormalities.

PubMed

Goswami, R; Pi, D; Pal, J; Cheng, K; Hudoba De Badyn, M

2015-06-01

The study evaluated the performance of a dynamic imaging telepathology system (Panoptiq(™) ) as a diagnostic aid to the identification of peripheral blood film (PBF) abnormalities. The study assumed a laboratory personnel working in a clinical laboratory were operating the telepathology system to seek diagnostic opinion from an external consulting hematopathologist. The study examined 100 blood films, encompassing 23 different hematological diseases, reactive or normal cases. The study revealed that with real-time image transmission in live scanning mode of operation, the telepathology system was able to aid reviewers in achieving excellent accuracy, that is correct interpretation of morphologic abnormalities obtained in 83/84 of the hematologic diseases and 12/12 of the reactive/normal conditions (Sensitivity: 0.99; Specificity: 1.00). In contrast, when only saved static images in digital capture mode of operation were reviewed remotely, interpretative omissions occurred in 8/84 of the hematologic diseases and 0/12 of the reactive/normal conditions (Sensitivity: 0.91; Specificity: 1.00). It is hypothesized that real-time operator-reviewer communication during live scanning played an important role in the identification of key morphologic abnormalities for review. Our study showed the Panoptiq system can be adopted reliably as a dynamic telepathology tool in aiding community laboratories in the triage of PBF cases for external diagnostic consultation. © 2014 John Wiley & Sons Ltd.

Grading of inflammatory disease activity in the sacroiliac joints with magnetic resonance imaging: comparison between short-tau inversion recovery and gadolinium contrast-enhanced sequences.

PubMed

Madsen, Karen Berenth; Egund, Niels; Jurik, Anne Grethe

2010-02-01

We investigated the potential concordance of 2 different magnetic resonance (MR) sequences - short-tau inversion recovery (STIR) and fat-saturated T1-weighted spin-echo after application of gadolinium (Gd) contrast medium to detect active bone marrow abnormalities at the sacroiliac joints (SIJ) in patients with spondyloarthritis (SpA). Blinded and using the Danish scoring method, we evaluated transaxial MR images of the 2 sequences in 40 patients with SpA with disease duration of 3-14 years. Both the cartilaginous and ligamentous portions of the SIJ were analyzed. There was a significant positive correlation between the activity scores obtained by STIR and Gd-enhanced sequences (p < 0.0001). Agreement in the detection of bone marrow abnormalities occurred in 60 of the 80 joints, 35 with and 25 without signs of active disease. Discordance with STIR-positive marrow activity scores occurred in only 11 joints; Gd-enhanced positive scores in 9 joints. The STIR sequence detected remnants of marrow activity in the periphery of chronic fatty replacement not seen or partly obscured on the Gd sequence. Small subchondral enhancing lesions may not be scored on the STIR sequence, mostly because of reduced image resolution. Active bone marrow abnormalities were detected nearly equally well with STIR and Gd-enhanced fat-suppressed T1 sequences in patients with SpA, with STIR being most sensitive to visualize active abnormalities in the periphery of chronic changes.

Repeated administration of the monoamine reuptake inhibitor BTS 74 398 induces ipsilateral circling in the 6-hydroxydopamine lesioned rat without sensitizing motor behaviours.

PubMed

Lane, E L; Cheetham, S C; Jenner, P

2005-01-01

BTS 74 398 (1-[1-(3,4-dichlorophenyl)cyclobutyl]-2-(3-diaminethylaminopropylthio)ethanone monocitrate) is a monoamine reuptake inhibitor that reverses motor deficits in MPTP-treated (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) common marmosets without provoking established dyskinesia. However, it is not known whether BTS 74 398 primes the basal ganglia for dyskinesia induction. In this study, the ability of BTS 74 398 to sensitize 6-hydroxydopamine (6-OHDA)-lesioned rats for the production of abnormal motor behaviours and the induction of striatal DeltaFosB were determined in comparison with l-3,4-dihydroxyphenylalanine methyl ester (L-dopa). Acute administration of BTS 74 398 induced a dose-dependent ipsilateral circling response in unilaterally 6-OHDA-lesioned rats whereas L-dopa produced dose-dependent contraversive rotation. The ipsilateral circling response to BTS 74 398 did not alter during 21 days of administration. In contrast, L-dopa treatment for 21 days caused a marked increase in rotational response. Repeated administration of both L-dopa and BTS 74 398 increased general motor activity and stereotypic behaviour. In L-dopa-treated rats, orolingual, locomotive, forelimb and axial abnormal movements developed whereas BTS 74 398 produced only locomotion with a side bias but no other abnormal movements. Sensitization of circling responses and the development of abnormal movements in 6-OHDA-lesioned rats have been associated with the potential of dopaminergic drugs to induce dyskinesia. Furthermore, striatal DeltaFosB immunoreactivity, shown to correlate with dyskinesia induction, was increased by L-dopa but was unaffected by repeated BTS 74 398 administration. The lack of such changes following repeated BTS 74 398 treatment suggests that it may be an effective antiparkinsonian therapy that is unlikely to produce involuntary movements.

Abnormal interhemispheric connectivity in male psychopathic offenders.

PubMed

Hoppenbrouwers, Sylco S; De Jesus, Danilo R; Sun, Yinming; Stirpe, Tania; Hofman, Dennis; McMaster, Jeff; Hughes, Ginny; Daskalakis, Zafiris J; Schutter, Dennis J L G

2014-01-01

Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders.

Abnormal interhemispheric connectivity in male psychopathic offenders

PubMed Central

Hoppenbrouwers, Sylco S.; De Jesus, Danilo R.; Sun, Yinming; Stirpe, Tania; Hofman, Dennis; McMaster, Jeff; Hughes, Ginny; Daskalakis, Zafiris J.; Schutter, Dennis J.L.G.

2014-01-01

Background Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. Methods We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. Results We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. Limitations The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. Conclusion To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders. PMID:23937798

Accuracy of saline contrast sonohysterography in detection of endometrial polyps and submucosal leiomyomas in women of reproductive age with abnormal uterine bleeding: systematic review and meta-analysis.

PubMed

Bittencourt, C A; Dos Santos Simões, R; Bernardo, W M; Fuchs, L F P; Soares Júnior, J M; Pastore, A R; Baracat, E C

2017-07-01

To analyze the diagnostic accuracy of two- (2D) and three- (3D) dimensional saline contrast sonohysterography (SCSH) in the detection of endometrial polyps and submucosal uterine leiomyomas in women of reproductive age with abnormal uterine bleeding compared with gold standard hysteroscopy. A systematic review of diagnostic studies that compared 2D- and/or 3D-SCSH with hysteroscopy and anatomopathology was conducted according to PRISMA and SEDATE recommendations. The databases MEDLINE, EMBASE and The Cochrane Library were searched electronically using specific terms with no restriction on language or publication year. Quality assessment of included studies was performed using the QUADAS-2 tool. Meta-analysis was performed with the Meta-DiSk program and data presented as forest plots and summary receiver-operating characteristics (SROC) curves. Pooled sensitivity, specificity and positive (LR+) and negative (LR-) likelihood ratios of SCSH in the detection of uterine cavity abnormalities were calculated. A total of 1398 citations were identified and five studies were included in the systematic review and meta-analysis. Pooled sensitivity and specificity of 2D-SCSH in detecting endometrial polyps were 93% (95% CI, 89-96%) and 81% (95% CI, 76-86%), respectively, with pooled LR+ of 5.41 (95% CI, 2.60-11.28) and LR- of 0.10 (95% CI, 0.06-0.17). In the detection of submucosal uterine leiomyomas, pooled sensitivity and specificity were 94% (95% CI, 89-97%) and 81% (95% CI, 76-86%), respectively, with pooled LR+ of 4.25 (95% CI, 2.20-8.21) and LR- of 0.11 (95% CI, 0.05-0.22). 2D-SCSH had good accuracy in detecting endometrial polyps and submucosal uterine leiomyomas, with areas under the SROC curves of 0.97 ± 0.02 and 0.97 ± 0.03, respectively. Studies that analyzed the diagnostic accuracy of 3D-SCSH could not be compared due to high heterogeneity related to menopausal status, type of technique used and primary outcome being investigation of infertility. 2D-SCSH proved to be a highly sensitive method for detection of endometrial polyps and submucosal uterine leiomyomas, making it a potential first-line diagnostic method in the work-up for women with abnormal uterine bleeding. More studies are needed on 3D-SCSH in women of reproductive age. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Effectiveness of Myocardial Contrast Echocardiography Quantitative Analysis during Adenosine Stress versus Visual Analysis before Percutaneous Therapy in Acute Coronary Pain: A Coronary Artery TIMI Grading Comparing Study

PubMed Central

Yang, Lixia; Mu, Yuming; Quaglia, Luiz Augusto; Tang, Qi; Guan, Lina; Wang, Chunmei; Shih, Ming Chi

2012-01-01

The study aim was to compare two different stress echocardiography interpretation techniques based on the correlation with thrombosis in myocardial infarction (TIMI ) flow grading from acute coronary syndrome (ACS) patients. Forty-one patients with suspected ACS were studied before diagnostic coronary angiography with myocardial contrast echocardiography (MCE) at rest and at stress. The correlation of visual interpretation of MCE and TIMI flow grade was significant. The quantitative analysis (myocardial perfusion parameters: A, β, and A × β) and TIMI flow grade were significant. MCE visual interpretation and TIMI flow grade had a high degree of agreement, on diagnosing myocardial perfusion abnormality. If one considers TIMI flow grade <3 as abnormal, MCE visual interpretation at rest had 73.1% accuracy with 58.2% sensitivity and 84.2% specificity and at stress had 80.4% accuracy with 76.6% sensitivity and 83.3% specificity. The MCE quantitative analysis has better accuracy with 100% of agreement with different level of TIMI flow grading. MCE quantitative analysis at stress has showed a direct correlation with TIMI flow grade, more significant than the visual interpretation technique. Further studies could measure the clinical relevance of this more objective approach to managing acute coronary syndrome patient before percutaneous coronary intervention (PCI). PMID:22778555

Decreased cortical activation in response to a motion stimulus in anisometropic amblyopic eyes using functional magnetic resonance imaging.

PubMed

Bonhomme, Gabrielle R; Liu, Grant T; Miki, Atsushi; Francis, Ellie; Dobre, M-C; Modestino, Edward J; Aleman, David O; Haselgrove, John C

2006-12-01

Motion perception abnormalities and extrastriate abnormalities have been suggested in amblyopia. Functional MRI (fMRI) and motion stimuli were used to study whether interocular differences in activation are detectable in motion-sensitive cortical areas in patients with anisometropic amblyopia. We performed fMRI at 1.5 T 4 control subjects (20/20 OU), 1 with monocular suppression (20/25), and 2 with anisometropic amblyopia (20/60, 20/800). Monocular suppression was thought to be form fruste of amblyopia. The experimental stimulus consisted of expanding and contracting concentric rings, whereas the control condition consisted of stationary concentric rings. Activation was determined by contrasting the 2 conditions for each eye. Significant fMRI activation and comparable right and left eye activation was found in V3a and V5 in all control subjects (Average z-values in L vs R contrast 0.42, 0.43) and in the subject with monocular suppression (z = 0.19). The anisometropes exhibited decreased extrastriate activation in their amblyopic eyes compared with the fellow eyes (zs = 2.12, 2.76). Our data suggest motion-sensitive cortical structures may be less active when anisometropic amblyopic eyes are stimulated with moving rings. These results support the hypothesis that extrastriate cortex is affected in anisometropic amblyopia. Although suggestive of a magnocellular defect, the exact mechanism is unclear.

Abnormal neural activity of brain regions in treatment-resistant and treatment-sensitive major depressive disorder: a resting-state fMRI study.

PubMed

Guo, Wen-bin; Liu, Feng; Chen, Jin-dong; Gao, Keming; Xue, Zhi-min; Xu, Xi-jia; Wu, Ren-rong; Tan, Chang-lian; Sun, Xue-li; Liu, Zhe-ning; Chen, Hua-fu; Zhao, Jing-ping

2012-10-01

Patients with treatment-resistant depression (TRD) and those with treatment-sensitive depression (TSD) responded to antidepressants differently. Previous studies have commonly shown that patients with TRD or TSD had abnormal neural activity in different brain regions. In the present study, we used a coherence-based ReHo (Cohe-ReHo) approach to test the hypothesis that patients with TRD or TSD had abnormal neural activity in different brain regions. Twenty-three patients with TRD, 22 with TSD, and 19 healthy subjects (HS) matched with gender, age, and education level participated in the study. ANOVA analysis revealed widespread differences in Cohe-ReHo values among the three groups in different brain regions which included bilateral superior frontal gyrus, bilateral cerebellum, left inferior temporal gyrus, left occipital cortex, and both sides of fusiform gyrus. Compared to HS, lower Cohe-ReHo values were observed in TRD group in bilateral superior frontal gyrus and left cerebellum; in contrast, in TSD group, lower Cohe-ReHo values were mainly found in bilateral superior frontal gyrus. Compared to TSD group, TRD group had lower Cohe-ReHo in bilateral cerebellum and higher Cohe-ReHo in left fusiform gyrus. There was a negative correlation between Cohe-ReHo values of the left fusiform gyrus and illness duration in the pooled patients (r = 0.480, p = 0.001). The sensitivity and specificity of cerebellar Cohe-ReHo values differentiating TRD from TSD were 83% and 86%, respectively. Compared to healthy controls, both TRD and TSD patients shared the majority of brain regions with abnormal neural activity. However, the lower Cohe-ReHo values in the cerebellum might be as a marker to differentiate TRD from TSD with high sensitivity and specificity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Detection of gastritis by single- and double-contrast radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thoeni, R.F.; Goldberg, H.I.; Ominsky, S.

1983-09-01

Sixty-eight patients with various types of gastritis, 23 patients with normal stomachs, and four patients with other gastric diseases were examined in a prospective study to assess the sensitivity and specificity of single-contrast (SC) and double-contrast (DC) upper gastrointestinal examinations in the evaluation of gastritis. All patients underwent endoscopy with biopsy followed first by DC and then by SC radiography. The respective sensitivities of SC and DC radiography were 58% and 72% for all examinations and 59% and 77% for adequate examinations only. The respective specificities were 59% and 55% based on all examinations. Useful radiographic features included polypoid defectsmore » and erosions detected by both methods, abnormal folds and flattened margins detected by the SC technique, and narrowed lumen and crenulated margins detected by the DC technique. In 93% of all cases, the correct diagnosis was based on two or more of these radiographic features. According to this study, the radiographic sensitivity in the detection of gastritis is reliable only in cases of moderate-to-severe disease and only when based on findings of the DC examination. Neither SC nor DC radiography should be used as the primary screening method for patients with suspected gastritis, and the radiographic diagnosis should be restricted to the terms ''erosive'' or ''nonerosive gastritis.''« less

Exercise thallium-201 tomographic scintigraphy in the diagnosis of coronary artery disease: emphasis on the effect of exercise level.

PubMed

Huang, P J; Chieng, P U; Lee, Y T; Chiang, F T; Tseng, Y Z; Liau, C S; Tseng, C D; Su, C T; Lien, W P

1992-11-01

Exercise thallium-201 imaging using single-photon emission computed tomography (SPECT) was evaluated in 154 patients with angiographically documented coronary artery disease (CAD) and in 25 normal subjects. Of the 154 patients with CAD, 134 (87%) had abnormal thallium images. By contrast, only 77 (50%) patients had ischemic ST-segment depression (p < 0.001). Among 25 normal subjects, 20 had normal exercise SPECT images. The specificity of exercise SPECT imaging (80% or 20/25) in excluding patients with CAD was not significantly higher than that of exercise electrocardiography (76% or 19/25). For the detection of individual vessel involvement by analysis of territories of perfusion abnormalities, the sensitivity and specificity of exercise SPECT were 72% and 96% for the left anterior descending, 78% and 85% for the right coronary, and 47% and 98% for the left circumflex artery. Ninety (group 1) of the 154 patients with CAD achieved adequate exercise end points (ischemic ST-segment depression or > 85% of maximal predicted heart rate) and 64 (group 2) did not. Exercise SPECT showed significantly more perfusion abnormalities in group 1 than in group 2 (96% vs 75%, p < 0.001). We conclude that: (1) exercise SPECT thallium imaging is more sensitive than exercise electrocardiography for detecting patients with CAD; (2) the sensitivity of the test is affected by the level of exercise; and (3) it is valuable in the identification of individual vessel involvement.

A novel iterative modified bicubic interpolation method enables high-contrast and high-resolution image generation for F-18 FDG-PET.

PubMed

Okizaki, Atsutaka; Nakayama, Michihiro; Nakajima, Kaori; Takahashi, Koji

2017-12-01

Positron emission tomography (PET) has become a useful and important technique in oncology. However, spatial resolution of PET is not high; therefore, small abnormalities can sometimes be overlooked with PET. To address this problem, we devised a novel algorithm, iterative modified bicubic interpolation method (IMBIM). IMBIM generates high resolution and -contrast image. The purpose of this study was to investigate the utility of IMBIM for clinical FDG positron emission tomography/X-ray computed tomography (PET/CT) imaging.We evaluated PET images from 1435 patients with malignant tumor and compared the contrast (uptake ratio of abnormal lesions to background) in high resolution image with the standard bicubic interpolation method (SBIM) and IMBIM. In addition to the contrast analysis, 340 out of 1435 patients were selected for visual evaluation by nuclear medicine physicians to investigate lesion detectability. Abnormal uptakes on the images were categorized as either absolutely abnormal or equivocal finding.The average of contrast with IMBIM was significantly higher than that with SBIM (P < .001). The improvements were prominent with large matrix sizes and small lesions. SBIM images showed abnormalities in 198 of 340 lesions (58.2%), while IMBIM indicated abnormalities in 312 (91.8%). There was statistically significant improvement in lesion detectability with IMBIM (P < .001).In conclusion, IMBIM generates high-resolution images with improved contrast and, therefore, may facilitate more accurate diagnoses in clinical practice. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Visual dysfunction in Parkinson’s disease

PubMed Central

Weil, Rimona S.; Schrag, Anette E.; Warren, Jason D.; Crutch, Sebastian J.; Lees, Andrew J.; Morris, Huw R.

2016-01-01

Patients with Parkinson’s disease have a number of specific visual disturbances. These include changes in colour vision and contrast sensitivity and difficulties with complex visual tasks such as mental rotation and emotion recognition. We review changes in visual function at each stage of visual processing from retinal deficits, including contrast sensitivity and colour vision deficits to higher cortical processing impairments such as object and motion processing and neglect. We consider changes in visual function in patients with common Parkinson’s disease-associated genetic mutations including GBA and LRRK2. We discuss the association between visual deficits and clinical features of Parkinson’s disease such as rapid eye movement sleep behavioural disorder and the postural instability and gait disorder phenotype. We review the link between abnormal visual function and visual hallucinations, considering current models for mechanisms of visual hallucinations. Finally, we discuss the role of visuo-perceptual testing as a biomarker of disease and predictor of dementia in Parkinson’s disease. PMID:27412389

Assessing the Effects of Software Platforms on Volumetric Segmentation of Glioblastoma

PubMed Central

Dunn, William D.; Aerts, Hugo J.W.L.; Cooper, Lee A.; Holder, Chad A.; Hwang, Scott N.; Jaffe, Carle C.; Brat, Daniel J.; Jain, Rajan; Flanders, Adam E.; Zinn, Pascal O.; Colen, Rivka R.; Gutman, David A.

2017-01-01

Background Radiological assessments of biologically relevant regions in glioblastoma have been associated with genotypic characteristics, implying a potential role in personalized medicine. Here, we assess the reproducibility and association with survival of two volumetric segmentation platforms and explore how methodology could impact subsequent interpretation and analysis. Methods Post-contrast T1- and T2-weighted FLAIR MR images of 67 TCGA patients were segmented into five distinct compartments (necrosis, contrast-enhancement, FLAIR, post contrast abnormal, and total abnormal tumor volumes) by two quantitative image segmentation platforms - 3D Slicer and a method based on Velocity AI and FSL. We investigated the internal consistency of each platform by correlation statistics, association with survival, and concordance with consensus neuroradiologist ratings using ordinal logistic regression. Results We found high correlations between the two platforms for FLAIR, post contrast abnormal, and total abnormal tumor volumes (spearman’s r(67) = 0.952, 0.959, and 0.969 respectively). Only modest agreement was observed for necrosis and contrast-enhancement volumes (r(67) = 0.693 and 0.773 respectively), likely arising from differences in manual and automated segmentation methods of these regions by 3D Slicer and Velocity AI/FSL, respectively. Survival analysis based on AUC revealed significant predictive power of both platforms for the following volumes: contrast-enhancement, post contrast abnormal, and total abnormal tumor volumes. Finally, ordinal logistic regression demonstrated correspondence to manual ratings for several features. Conclusion Tumor volume measurements from both volumetric platforms produced highly concordant and reproducible estimates across platforms for general features. As automated or semi-automated volumetric measurements replace manual linear or area measurements, it will become increasingly important to keep in mind that measurement differences between segmentation platforms for more detailed features could influence downstream survival or radio genomic analyses. PMID:29600296

Real time myocardial contrast echocardiography during supine bicycle stress and continuous infusion of contrast agent. Cutoff values for myocardial contrast replenishment discriminating abnormal myocardial perfusion.

PubMed

Miszalski-Jamka, Tomasz; Kuntz-Hehner, Stefanie; Schmidt, Harald; Hammerstingl, Christoph; Tiemann, Klaus; Ghanem, Alexander; Troatz, Clemens; Lüderitz, Berndt; Omran, Heyder

2007-07-01

Myocardial contrast echocardiography (MCE) is a new imaging modality for diagnosing coronary artery disease (CAD). The aim of our study was to evaluate feasibility of qualitative myocardial contrast replenishment (RP) assessment during supine bicycle stress MCE and find out cutoff values for such analysis, which could allow accurate detection of CAD. Forty-four consecutive patients, scheduled for coronary angiography (CA) underwent supine bicycle stress two-dimensional echocardiography (2DE). During the same session, MCE was performed at peak stress and post stress. Ultrasound contrast agent (SonoVue) was administered in continuous mode using an infusion pump (BR-INF 100, Bracco Research). Seventeen-segment model of left ventricle was used in analysis. MCE was assessed off-line in terms of myocardial contrast opacification and RP. RP was evaluated on the basis of the number of cardiac cycles required to refill the segment with contrast after its prior destruction with high-power frames. Determination of cutoff values for RP assessment was performed by means of reference intervals and receiver operating characteristic analysis. Quantitative CA was carried out using CAAS system. MCE could be assessed in 42 patients. CA revealed CAD in 25 patients. Calculated cutoff values for RP-analysis (peak-stress RP >3 cardiac cycles and difference between peak stress and post stress RP >0 cardiac cycles) provided sensitive (88%) and accurate (88%) detection of CAD. Sensitivity and accuracy of 2DE were 76% and 79%, respectively. Qualitative RP-analysis based on the number of cardiac cycles required to refill myocardium with contrast is feasible during supine bicycle stress MCE and enables accurate detection of CAD.

Linking assumptions in amblyopia

PubMed Central

LEVI, DENNIS M.

2017-01-01

Over the last 35 years or so, there has been substantial progress in revealing and characterizing the many interesting and sometimes mysterious sensory abnormalities that accompany amblyopia. A goal of many of the studies has been to try to make the link between the sensory losses and the underlying neural losses, resulting in several hypotheses about the site, nature, and cause of amblyopia. This article reviews some of these hypotheses, and the assumptions that link the sensory losses to specific physiological alterations in the brain. Despite intensive study, it turns out to be quite difficult to make a simple linking hypothesis, at least at the level of single neurons, and the locus of the sensory loss remains elusive. It is now clear that the simplest notion—that reduced contrast sensitivity of neurons in cortical area V1 explains the reduction in contrast sensitivity—is too simplistic. Considerations of noise, noise correlations, pooling, and the weighting of information also play a critically important role in making perceptual decisions, and our current models of amblyopia do not adequately take these into account. Indeed, although the reduction of contrast sensitivity is generally considered to reflect “early” neural changes, it seems plausible that it reflects changes at many stages of visual processing. PMID:23879956

Retinal architecture and mfERG: Optic nerve head component response characteristics in MS.

PubMed

Schnurman, Zane S; Frohman, Teresa C; Beh, Shin C; Conger, Darrel; Conger, Amy; Saidha, Shiv; Galetta, Steven; Calabresi, Peter A; Green, Ari J; Balcer, Laura J; Frohman, Elliot M

2014-05-27

To describe a novel neurophysiologic signature of the retinal ganglion cell and to elucidate its relationship to abnormalities in validated structural and functional measures of the visual system. We used multifocal electroretinogram-generated optic nerve head component (ONHC) responses from normal subjects (n = 18), patients with multiple sclerosis (MS) (n = 18), and those with glaucoma (n = 3). We then characterized the relationship between ONHC response abnormalities and performance on low-contrast visual acuity, multifocal visual-evoked potential-induced cortical responses, and average and quadrant retinal nerve fiber layer (RNFL) thicknesses, as measured by spectral-domain optical coherence tomography. Compared with the eyes of normal subjects, the eyes of patients with MS exhibited an increased number of abnormal or absent ONHC responses (p < 0.0001). For every 7-letter reduction in low-contrast letter acuity, there were corresponding 4.6 abnormal ONHC responses at 2.5% contrast (p < 0.0001) and 6.6 abnormalities at the 1.25% contrast level (p < 0.0001). Regarding average RNFL thickness, for each 10-μm thickness reduction, we correspondingly observed 6.8 abnormal ONHC responses (p = 0.0002). The most robust association was between RNFL thinning in the temporal quadrant and ONHC response abnormalities (p < 0.0001). Further characterization of ONHC abnormalities (those that are reversible and irreversible) may contribute to the development of novel neurotherapeutic strategies aimed at achieving neuroprotective, and perhaps even neurorestorative, effects in disorders that target the CNS in general, and MS in particular. © 2014 American Academy of Neurology.

Silver nanoparticles induce developmental stage-specific embryonic phenotypes in zebrafish

NASA Astrophysics Data System (ADS)

Lee, Kerry J.; Browning, Lauren M.; Nallathamby, Prakash D.; Osgood, Christopher J.; Xu, Xiao-Hong Nancy

2013-11-01

Much is anticipated from the development and deployment of nanomaterials in biological organisms, but concerns remain regarding their biocompatibility and target specificity. Here we report our study of the transport, biocompatibility and toxicity of purified and stable silver nanoparticles (Ag NPs, 13.1 +/- 2.5 nm in diameter) upon the specific developmental stages of zebrafish embryos using single NP plasmonic spectroscopy. We find that single Ag NPs passively diffuse into five different developmental stages of embryos (cleavage, early-gastrula, early-segmentation, late-segmentation, and hatching stages), showing stage-independent diffusion modes and diffusion coefficients. Notably, the Ag NPs induce distinctive stage and dose-dependent phenotypes and nanotoxicity, upon their acute exposure to the Ag NPs (0-0.7 nM) for only 2 h. The late-segmentation embryos are most sensitive to the NPs with the lowest critical concentration (CNP,c << 0.02 nM) and highest percentages of cardiac abnormalities, followed by early-segmentation embryos (CNP,c < 0.02 nM), suggesting that disruption of cell differentiation by the NPs causes the most toxic effects on embryonic development. The cleavage-stage embryos treated with the NPs develop into a wide variety of phenotypes (abnormal finfold, tail/spinal cord flexure, cardiac malformation/edema, yolk sac edema, and acephaly). These organ structures are not yet developed in cleavage-stage embryos, suggesting that the earliest determinative events to create these structures are ongoing, and disrupted by NPs, which leads to the downstream effects. In contrast, the hatching embryos are most resistant to the Ag NPs, and majority of embryos (94%) develop normally, and none of them develop abnormally. Interestingly, early-gastrula embryos are less sensitive to the NPs than cleavage and segmentation stage embryos, and do not develop abnormally. These important findings suggest that the Ag NPs are not simple poisons, and they can target specific pathways in development, and potentially enable target specific study and therapy for early embryonic development.Much is anticipated from the development and deployment of nanomaterials in biological organisms, but concerns remain regarding their biocompatibility and target specificity. Here we report our study of the transport, biocompatibility and toxicity of purified and stable silver nanoparticles (Ag NPs, 13.1 +/- 2.5 nm in diameter) upon the specific developmental stages of zebrafish embryos using single NP plasmonic spectroscopy. We find that single Ag NPs passively diffuse into five different developmental stages of embryos (cleavage, early-gastrula, early-segmentation, late-segmentation, and hatching stages), showing stage-independent diffusion modes and diffusion coefficients. Notably, the Ag NPs induce distinctive stage and dose-dependent phenotypes and nanotoxicity, upon their acute exposure to the Ag NPs (0-0.7 nM) for only 2 h. The late-segmentation embryos are most sensitive to the NPs with the lowest critical concentration (CNP,c << 0.02 nM) and highest percentages of cardiac abnormalities, followed by early-segmentation embryos (CNP,c < 0.02 nM), suggesting that disruption of cell differentiation by the NPs causes the most toxic effects on embryonic development. The cleavage-stage embryos treated with the NPs develop into a wide variety of phenotypes (abnormal finfold, tail/spinal cord flexure, cardiac malformation/edema, yolk sac edema, and acephaly). These organ structures are not yet developed in cleavage-stage embryos, suggesting that the earliest determinative events to create these structures are ongoing, and disrupted by NPs, which leads to the downstream effects. In contrast, the hatching embryos are most resistant to the Ag NPs, and majority of embryos (94%) develop normally, and none of them develop abnormally. Interestingly, early-gastrula embryos are less sensitive to the NPs than cleavage and segmentation stage embryos, and do not develop abnormally. These important findings suggest that the Ag NPs are not simple poisons, and they can target specific pathways in development, and potentially enable target specific study and therapy for early embryonic development. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03210h

Shades of white: diffusion properties of T1- and FLAIR-defined white matter signal abnormalities differ in stages from cognitively normal to dementia.

PubMed

Riphagen, Joost M; Gronenschild, Ed H B M; Salat, David H; Freeze, Whitney M; Ivanov, Dimo; Clerx, Lies; Verhey, Frans R J; Aalten, Pauline; Jacobs, Heidi I L

2018-08-01

The underlying pathology of white matter signal abnormalities (WMSAs) is heterogeneous and may vary dependent on the magnetic resonance imaging contrast used to define them. We investigated differences in white matter diffusivity as an indicator for white matter integrity underlying WMSA based on T1-weighted and fluid-attenuated inversion recovery (FLAIR) imaging contrast. In addition, we investigated which white matter region of interest (ROI) could predict clinical diagnosis best using diffusion metrics. One hundred three older individuals with varying cognitive impairment levels were included and underwent neuroimaging. Diffusion metrics were extracted from WMSA areas based on T1 and FLAIR contrast and from their overlapping areas, the border surrounding the WMSA and the normal-appearing white matter (NAWM). Regional diffusivity differences were calculated with linear mixed effects models. Multinomial logistic regression determined which ROI diffusion values classified individuals best into clinically defined diagnostic groups. T1-based WMSA showed lower white matter integrity compared to FLAIR WMSA-defined regions. Diffusion values of NAWM predicted diagnostic group best compared to other ROI's. To conclude, T1- or FLAIR-defined WMSA provides distinct information on the underlying white matter integrity associated with cognitive decline. Importantly, not the "diseased" but the NAWM is a potentially sensitive indicator for cognitive brain health status. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Probabilistic images (PBIS): A concise image representation technique for multiple parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, L.C.; Yeh, S.H.; Chen, Z.

1984-01-01

Based on m parametric images (PIs) derived from a dynamic series (DS), each pixel of DS is regarded as an m-dimensional vector. Given one set of normal samples (pixels) N and another of abnormal samples A, probability density functions (pdfs) of both sets are estimated. Any unknown sample is classified into N or A by calculating the probability of its being in the abnormal set using the Bayes' theorem. Instead of estimating the multivariate pdfs, a distance ratio transformation is introduced to map the m-dimensional sample space to one dimensional Euclidean space. Consequently, the image that localizes the regional abnormalitiesmore » is characterized by the probability of being abnormal. This leads to the new representation scheme of PBIs. Tc-99m HIDA study for detecting intrahepatic lithiasis (IL) was chosen as an example of constructing PBI from 3 parameters derived from DS and such a PBI was compared with those 3 PIs, namely, retention ratio image (RRI), peak time image (TNMAX) and excretion mean transit time image (EMTT). 32 normal subjects and 20 patients with proved IL were collected and analyzed. The resultant sensitivity and specificity of PBI were 97% and 98% respectively. They were superior to those of any of the 3 PIs: RRI (94/97), TMAX (86/88) and EMTT (94/97). Furthermore, the contrast of PBI was much better than that of any other image. This new image formation technique, based on multiple parameters, shows the functional abnormalities in a structural way. Its good contrast makes the interpretation easy. This technique is powerful compared to the existing parametric image method.« less

Mass screening of multiple abdominal solid organs using mobile helical computed tomography scanner--a preliminary report.

PubMed

Ishikawa, Susumu; Aoki, Jun; Ohwada, Susumu; Takahashi, Toru; Morishita, Yasuo; Ueda, Keisuke

2007-04-01

The possibility of a new screening procedure for multiple abdominal solid organs using a mobile helical computed tomography (CT) scanner was evaluated. A total of 4,543 residents, who were 40 years of age or older, received CT scanning without contrast medium. The mean age of participants was 64 years including 2,022 males and 2,521 females. A total of 2,105 abnormal findings were uniquely detected in 1,594 participants. Liver and kidney diseases including ureter occupied around 30% of total abnormal findings, respectively. Besides frequent cystic or calcified lesions, solid tumours were suspected in 56 lesions, which received further examination by specialized physicians. Five (9%) of them were confirmed as being malignant tumours including pancreatic cancer in two patients, and liver, lung and ovary cancers in one patient each, respectively. All five patients with each malignant lesion received curative operations. Small-sized abdominal aortic aneurysms and heart valve diseases were uniquely found in 22 and two patients, respectively. Qualitative diagnoses of solid tumours were difficult using CT findings without contrast medium. CT screening procedures require further investigation in aspect of the selection of examinees, CT scanning procedure, sensitivity and specificity, and cost-effectiveness.

Magnetic resonance imaging of blood-brain barrier permeability in ischemic stroke using diffusion-weighted arterial spin labeling in rats.

PubMed

Tiwari, Yash V; Lu, Jianfei; Shen, Qiang; Cerqueira, Bianca; Duong, Timothy Q

2017-08-01

Diffusion-weighted arterial spin labeling magnetic resonance imaging has recently been proposed to quantify the rate of water exchange (K w ) across the blood-brain barrier in humans. This study aimed to evaluate the blood-brain barrier disruption in transient (60 min) ischemic stroke using K w magnetic resonance imaging with cross-validation by dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology in the same rats. The major findings were: (i) at 90 min after stroke (30 min after reperfusion), group K w magnetic resonance imaging data showed no significant blood-brain barrier permeability changes, although a few animals showed slightly abnormal K w . Dynamic contrast-enhanced magnetic resonance imaging confirmed this finding in the same animals. (ii) At two days after stroke, K w magnetic resonance imaging revealed significant blood-brain barrier disruption. Regions with abnormal K w showed substantial overlap with regions of hyperintense T 2 (vasogenic edema) and hyperperfusion. Dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology confirmed these findings in the same animals. The K w values in the normal contralesional hemisphere and the ipsilesional ischemic core two days after stroke were: 363 ± 17 and 261 ± 18 min -1 , respectively (P < 0.05, n = 9). K w magnetic resonance imaging is sensitive to blood-brain barrier permeability changes in stroke, consistent with dynamic contrast-enhanced magnetic resonance imaging and Evans blue extravasation. K w magnetic resonance imaging offers advantages over existing techniques because contrast agent is not needed and repeated measurements can be made for longitudinal monitoring or averaging.

Contrast sensitivity test and conventional and high frequency audiometry: information beyond that required to prescribe lenses and headsets

NASA Astrophysics Data System (ADS)

Comastri, S. A.; Martin, G.; Simon, J. M.; Angarano, C.; Dominguez, S.; Luzzi, F.; Lanusse, M.; Ranieri, M. V.; Boccio, C. M.

2008-04-01

In Optometry and in Audiology, the routine tests to prescribe correction lenses and headsets are respectively the visual acuity test (the first chart with letters was developed by Snellen in 1862) and conventional pure tone audiometry (the first audiometer with electrical current was devised by Hartmann in 1878). At present there are psychophysical non invasive tests that, besides evaluating visual and auditory performance globally and even in cases catalogued as normal according to routine tests, supply early information regarding diseases such as diabetes, hypertension, renal failure, cardiovascular problems, etc. Concerning Optometry, one of these tests is the achromatic luminance contrast sensitivity test (introduced by Schade in 1956). Concerning Audiology, one of these tests is high frequency pure tone audiometry (introduced a few decades ago) which yields information relative to pathologies affecting the basal cochlea and complements data resulting from conventional audiometry. These utilities of the contrast sensitivity test and of pure tone audiometry derive from the facts that Fourier components constitute the basis to synthesize stimuli present at the entrance of the visual and auditory systems; that these systems responses depend on frequencies and that the patient's psychophysical state affects frequency processing. The frequency of interest in the former test is the effective spatial frequency (inverse of the angle subtended at the eye by a cycle of a sinusoidal grating and measured in cycles/degree) and, in the latter, the temporal frequency (measured in cycles/sec). Both tests have similar duration and consist in determining the patient's threshold (corresponding to the inverse multiplicative of the contrast or to the inverse additive of the sound intensity level) for each harmonic stimulus present at the system entrance (sinusoidal grating or pure tone sound). In this article the frequencies, standard normality curves and abnormal threshold shifts inherent to the contrast sensitivity test (which for simplicity could be termed "visionmetry") and to pure tone audiometry (also termed auditory sensitivity test) are analyzed with the purpose of contributing to divulge their ability to supply early information associated to pathologies not solely related to the visual and auditory systems respectively.

[Amblyopia].

PubMed

Orssaud, C

2014-06-01

Amblyopia is a developmental disorder of the entire visual system, including the extra-striate cortex. It manifests mainly by impaired visual acuity in the amblyopic eye. However, other abnormalities of visual function can be observed, such as decreased contrast sensitivity and stereoscopic vision, and some abnormalities can be found in the "good" eye. Amblyopia occurs during the critical period of brain development. It may be due to organic pathology of the visual pathways, visual deprivation or functional abnormalities, mainly anisometropia or strabismus. The diagnosis of amblyopia must be confirmed prior to treatment. Confirmation is based on cycloplegic refraction, visual acuity measurement and orthoptic assessment. However, screening for amblyopia and associated risk factors permits earlier diagnosis and treatment. The younger the child, the more effective the treatment, and it can only be achieved during the critical period. It requires parental cooperation in order to be effective and is based on occlusion or penalization of the healthy eye. The amblyopic eye may then develop better vision. Maintenance therapy must be performed until the end of the critical period to avoid recurrence. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Imaging gray matter with concomitant null point imaging from the phase sensitive inversion recovery sequence.

PubMed

Mougin, Olivier; Abdel-Fahim, Rasha; Dineen, Robert; Pitiot, Alain; Evangelou, Nikos; Gowland, Penny

2016-11-01

To present an improved three-dimensional (3D) interleaved phase sensitive inversion recovery (PSIR) sequence including a concomitantly acquired new contrast, null point imaging (NPI), to help detect and classify abnormalities in cortical gray matter. The 3D gradient echo PSIR images were acquired at 0.6 mm isotropic resolution on 11 multiple sclerosis (MS) patients and 9 controls subjects using a 7 Tesla (T) MRI scanner, and 2 MS patients at 3T. Cortical abnormalities were delineated on the NPI/PSIR data and later classified according to position in the cortex. The NPI helped detect cortical lesions within the cortical ribbon with increased, positive contrast compared with the PSIR. It also provided improved intrinsic delineation of the ribbon, increasing confidence in classifying the lesions' locations. The proposed PSIR facilitates the classification of cortical lesions by providing two T 1 -weighted 3D datasets with isotropic resolution, including the NPI showing cortical lesions with clear delineation of the gray/white matter boundary and minimal partial volume effects. Magn Reson Med 76:1512-1516, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Selective effects of 5-HT2C receptor modulation on performance of a novel valence-probe visual discrimination task and probabilistic reversal learning in mice.

PubMed

Phillips, Benjamin U; Dewan, Sigma; Nilsson, Simon R O; Robbins, Trevor W; Heath, Christopher J; Saksida, Lisa M; Bussey, Timothy J; Alsiö, Johan

2018-04-22

Dysregulation of the serotonin (5-HT) system is a pathophysiological component in major depressive disorder (MDD), a condition closely associated with abnormal emotional responsivity to positive and negative feedback. However, the precise mechanism through which 5-HT tone biases feedback responsivity remains unclear. 5-HT2C receptors (5-HT2CRs) are closely linked with aspects of depressive symptomatology, including abnormalities in reinforcement processes and response to stress. Thus, we aimed to determine the impact of 5-HT2CR function on response to feedback in biased reinforcement learning. We used two touchscreen assays designed to assess the impact of positive and negative feedback on probabilistic reinforcement in mice, including a novel valence-probe visual discrimination (VPVD) and a probabilistic reversal learning procedure (PRL). Systemic administration of a 5-HT2CR agonist and antagonist resulted in selective changes in the balance of feedback sensitivity bias on these tasks. Specifically, on VPVD, SB 242084, the 5-HT2CR antagonist, impaired acquisition of a discrimination dependent on appropriate integration of positive and negative feedback. On PRL, SB 242084 at 1 mg/kg resulted in changes in behaviour consistent with reduced sensitivity to positive feedback. In contrast, WAY 163909, the 5-HT2CR agonist, resulted in changes associated with increased sensitivity to positive feedback and decreased sensitivity to negative feedback. These results suggest that 5-HT2CRs tightly regulate feedback sensitivity bias in mice with consequent effects on learning and cognitive flexibility and specify a framework for the influence of 5-HT2CRs on sensitivity to reinforcement.

Hypoconnectivity and hyperfrontality in retired American football players.

PubMed

Hampshire, Adam; MacDonald, Alex; Owen, Adrian M

2013-10-17

Recent research has raised concerns about the long-term neurological consequences of repetitive concussive and sub-concussive injuries in professional players of American Football. Despite this interest, the neural and psychological status of retired players remains unknown. Here, we evaluated the performances and brain activation patterns of retired National Football League players (NFL alumni) relative to controls using an fMRI-optimised neuropsychological test of executive function. Behaviourally, the NFL alumni showed only modest performance deficits on the executive task. By contrast, they showed pronounced hyperactivation and hypoconnectivity of the dorsolateral frontal and frontopolar cortices. Critically, abnormal frontal-lobe function was correlated with the number of times that NFL alumni reported having been removed from play after head injury and was evident in individual players. These results support the hypothesis that NFL alumni have a heightened probability of developing executive dysfunction and suggest that fMRI provides the most sensitive biomarker of the underlying neural abnormality.

Hypoconnectivity and Hyperfrontality in Retired American Football Players

NASA Astrophysics Data System (ADS)

Hampshire, Adam; MacDonald, Alex; Owen, Adrian M.

2013-10-01

Recent research has raised concerns about the long-term neurological consequences of repetitive concussive and sub-concussive injuries in professional players of American Football. Despite this interest, the neural and psychological status of retired players remains unknown. Here, we evaluated the performances and brain activation patterns of retired National Football League players (NFL alumni) relative to controls using an fMRI-optimised neuropsychological test of executive function. Behaviourally, the NFL alumni showed only modest performance deficits on the executive task. By contrast, they showed pronounced hyperactivation and hypoconnectivity of the dorsolateral frontal and frontopolar cortices. Critically, abnormal frontal-lobe function was correlated with the number of times that NFL alumni reported having been removed from play after head injury and was evident in individual players. These results support the hypothesis that NFL alumni have a heightened probability of developing executive dysfunction and suggest that fMRI provides the most sensitive biomarker of the underlying neural abnormality.

Anodal transcranial direct current stimulation transiently improves contrast sensitivity and normalizes visual cortex activation in individuals with amblyopia.

PubMed

Spiegel, Daniel P; Byblow, Winston D; Hess, Robert F; Thompson, Benjamin

2013-10-01

Amblyopia is a neurodevelopmental disorder of vision that is associated with abnormal patterns of neural inhibition within the visual cortex. This disorder is often considered to be untreatable in adulthood because of insufficient visual cortex plasticity. There is increasing evidence that interventions that target inhibitory interactions within the visual cortex, including certain types of noninvasive brain stimulation, can improve visual function in adults with amblyopia. We tested the hypothesis that anodal transcranial direct current stimulation (a-tDCS) would improve visual function in adults with amblyopia by enhancing the neural response to inputs from the amblyopic eye. Thirteen adults with amblyopia participated and contrast sensitivity in the amblyopic and fellow fixing eye was assessed before, during and after a-tDCS or cathodal tDCS (c-tDCS). Five participants also completed a functional magnetic resonance imaging (fMRI) study designed to investigate the effect of a-tDCS on the blood oxygen level-dependent response within the visual cortex to inputs from the amblyopic versus the fellow fixing eye. A subgroup of 8/13 participants showed a transient improvement in amblyopic eye contrast sensitivity for at least 30 minutes after a-tDCS. fMRI measurements indicated that the characteristic cortical response asymmetry in amblyopes, which favors the fellow eye, was reduced by a-tDCS. These preliminary results suggest that a-tDCS deserves further investigation as a potential tool to enhance amblyopia treatment outcomes in adults.

Emotion-motion interactions in conversion disorder: an FMRI study.

PubMed

Aybek, Selma; Nicholson, Timothy R; O'Daly, Owen; Zelaya, Fernando; Kanaan, Richard A; David, Anthony S

2015-01-01

To evaluate the neural correlates of implicit processing of negative emotions in motor conversion disorder (CD) patients. An event related fMRI task was completed by 12 motor CD patients and 14 matched healthy controls using standardised stimuli of faces with fearful and sad emotional expressions in comparison to faces with neutral expressions. Temporal changes in the sensitivity to stimuli were also modelled and tested in the two groups. We found increased amygdala activation to negative emotions in CD compared to healthy controls in region of interest analyses, which persisted over time consistent with previous findings using emotional paradigms. Furthermore during whole brain analyses we found significantly increased activation in CD patients in areas involved in the 'freeze response' to fear (periaqueductal grey matter), and areas involved in self-awareness and motor control (cingulate gyrus and supplementary motor area). In contrast to healthy controls, CD patients exhibited increased response amplitude to fearful stimuli over time, suggesting abnormal emotional regulation (failure of habituation / sensitization). Patients with CD also activated midbrain and frontal structures that could reflect an abnormal behavioral-motor response to negative including threatening stimuli. This suggests a mechanism linking emotions to motor dysfunction in CD.

Pitfalls in the detection of cholesterol in Huntington's disease models.

PubMed

Marullo, Manuela; Valenza, Marta; Leoni, Valerio; Caccia, Claudio; Scarlatti, Chiara; De Mario, Agnese; Zuccato, Chiara; Di Donato, Stefano; Carafoli, Ernesto; Cattaneo, Elena

2012-10-11

Background Abnormalities in brain cholesterol homeostasis have been reported in Huntington's disease (HD), an adult-onset neurodegenerative disorder caused by an expansion in the number of CAG repeats in the huntingtin (HTT) gene. However, the results have been contradictory with respect to whether cholesterol levels increase or decrease in HD models. Biochemical and mass spectrometry methods show reduced levels of cholesterol precursors and cholesterol in HD cells and in the brains of several HD animal models. Abnormal brain cholesterol homeostasis was also inferred from studies in HD patients. In contrast, colorimetric and enzymatic methods indicate cholesterol accumulation in HD cells and tissues. Here we used several methods to investigate cholesterol levels in cultured cells in the presence or absence of mutant HTT protein. Results Colorimetric and enzymatic methods with low sensitivity gave variable results, whereas results from a sensitive analytical method, gas chromatography-mass spectrometry, were more reliable. Sample preparation, high cell density and cell clonality also influenced the detection of intracellular cholesterol. Conclusions Detection of cholesterol in HD samples by colorimetric and enzymatic assays should be supplemented by detection using more sensitive analytical methods. Care must be taken to prepare the sample appropriately. By evaluating lathosterol levels using isotopic dilution mass spectrometry, we confirmed reduced cholesterol biosynthesis in knock-in cells expressing the polyQ mutation in a constitutive or inducible manner. *Correspondence should be addressed to Elena Cattaneo: elena.cattaneo@unimi.it.

Extinction is not a natural consequence of unilateral spatial neglect: evidence from contrast detection experiments.

PubMed

Pavlovskaya, Marina; Soroker, Nachum; Bonneh, Yoram

2007-06-15

To investigate whether the expression of visual extinction is dependent upon the contralesional low saliency existing in neglect, we tested stroke patients with neglect and extinction, as well as normal controls, on detection of a peripheral Gabor patch, while a competing patch was presented simultaneously on the other side. To compensate for uneven saliency we set the contrast level relative to the detection threshold on each side. Patients showed contralesional extinction even for stimuli set at threshold level. They differed from controls in their sensitivity to changes in relative contrast between sides, showing stronger tendency for extinction and requiring much higher contrast increments in the target patch in order to eliminate extinction. The differences between normal and pathological extinction, shown despite compensation for contralesional perceptual attenuation due to neglect, suggest an additional extinction-specific deficit related to an abnormal interplay between the bilaterally presented stimuli. These findings have important theoretical implications concerning the relationship between neglect and extinction. They demonstrate that the hypothetical 'attentional gradient', taken to explain reduced saliency of stimuli in the neglected side, cannot fully account for the phenomenon of extinction.

Quantification of traumatic meningeal injury using dynamic contrast enhanced (DCE) fluid-attenuated inversion recovery (FLAIR) imaging

NASA Astrophysics Data System (ADS)

Castro, Marcelo A.; Williford, Joshua P.; Cota, Martin R.; MacLaren, Judy M.; Dardzinski, Bernard J.; Latour, Lawrence L.; Pham, Dzung L.; Butman, John A.

2016-03-01

Traumatic meningeal injury is a novel imaging marker of traumatic brain injury, which appears as enhancement of the dura on post-contrast T2-weighted FLAIR images, and is likely associated with inflammation of the meninges. Dynamic Contrast Enhanced MRI provides a better discrimination of abnormally perfused regions. A method to properly identify those regions is presented. Images of seventeen patients scanned within 96 hours of head injury with positive traumatic meningeal injury were normalized and aligned. The difference between the pre- and last post-contrast acquisitions was segmented and voxels in the higher class were spatially clustered. Spatial and morphological descriptors were used to identify the regions of enhancement: a) centroid; b) distance to the brain mask from external voxels; c) distance from internal voxels; d) size; e) shape. The method properly identified thirteen regions among all patients. The method failed in one case due to the presence of a large brain lesion that altered the mask boundaries. Most false detections were correctly rejected resulting in a sensitivity and specificity of 92.9% and 93.6%, respectively.

Physiology of leptin: energy homeostasis, neuroendocrine function and metabolism

PubMed Central

Park, Hyeong-Kyu; Ahima, Rexford S.

2014-01-01

Leptin is secreted by adipose tissue and regulates energy homeostasis, neuroendocrine function, metabolism, immune function and other systems through its effects on the central nervous system and peripheral tissues. Leptin administration has been shown to restore metabolic and neuroendocrine abnormalities in individuals with leptin-deficient states, including hypothalamic amenorrhea and lipoatrophy. In contrast, obese individuals are resistant to leptin. Recombinant leptin is beneficial in patients with congenital leptin deficiency or generalized lipodystrophy. However, further research on molecular mediators of leptin resistance is needed for the development of targeted leptin sensitizing therapies for obesity and related metabolic diseases. PMID:25199978

Computed tomography versus water-soluble contrast swallow in the detection of intrathoracic anastomotic leak complicating esophagogastrectomy (Ivor Lewis): a prospective study in 97 patients.

PubMed

Strauss, Christiane; Mal, Frederic; Perniceni, Thierry; Bouzar, Nadia; Lenoir, Stephane; Gayet, Brice; Palau, Robert

2010-04-01

Water-soluble contrast swallow (CS) is usually performed before refeeding for anastomosis assessment after esophagectomy with intrathoracic anastomosis but the sensitivity of CS is low. Another diagnostic approach is based on analysis of computed tomography (CT) scan with oral contrast and of CT mediastinal air images. We undertook to compare them prospectively. Ninety-seven patients with an esophageal carcinoma operated by intrathoracic anastomosis were included prospectively in a study based on a CT scan at postoperative day 3 (without oral and intravenous contrast) and CT scan and CS at day 7. CT scan analysis consisted of assessing contrast and air leakage. In case of doubt, an endoscopy was done. A diagnosis of anastomotic leak was made in 13 patients (13.4%), in 2 cases before day 7 and in 3 beyond day 7. At day 3, 94 CT scans were performed, but the diagnostic value was poor. In 95 patients with both CS and CT scan at day 7, CS disclosed a leak in 5 of 11, and CT scan was abnormal in 8 of 11. Leakage of contrast and/or presence of mediastinal gas had the best negative predictive value (95.8%). Endoscopy was done in 16 patients with only mediastinal gas at day 7 CT scan. It disclosed a normal anastomosis in 11, fibrin deposits in 4, and a leak in 1. In comparison with CS only, CT at day 7 improves the sensitivity and negative predictive value for diagnosing an anastomotic leak. In case of doubt endoscopy is advisable. This approach provides an accurate assessment of the anastomosis before refeeding.

CT urography of urinary diversions with enhanced CT digital radiography: preliminary experience.

PubMed

Sudakoff, Gary S; Guralnick, Michael; Langenstroer, Peter; Foley, W Dennis; Cihlar, Krista L; Shakespear, Jonathan S; See, William A

2005-01-01

The purpose of this study was to determine if 3D-rendered CT urography (CTU) depicts both normal and abnormal findings in patients with urinary diversions and if the addition of contrast-enhanced CT digital radiography (CTDR) improves opacification of the urinary collecting system. Thirty CTU and contrast-enhanced CTDR examinations were performed in 24 patients who underwent cystectomy for bladder cancer. Indications for evaluation included hematuria, tumor surveillance, or suspected diversion malfunction. All examinations were evaluated without knowledge of the stage or grade of a patient's tumor and were compared with the clinical records. Opacification of the urinary collecting system was evaluated with 3D CTU alone, contrast-enhanced CTDR alone, and combined CTU and CTDR. Nine abnormalities were identified including distal ureteral strictures (n = 4), vascular compression of the mid left ureter (n = 1), scarring of the mid right pole infundibulum (n = 1), bilateral hydronephrosis and hydroureter (n = 1), urinary reservoir calculus (n = 1), and tumor recurrence invading the afferent limb of the neobladder (n = 1). Eight of the nine detected abnormalities were surgically or pathologically confirmed. All abnormalities were identified on all three imaging techniques but were best seen on 3D CTU and enhanced CTDR images. Incomplete opacification of the urinary collecting system occurred in 17 patients with CTU alone, 12 patients with contrast-enhanced CTDR alone, and nine patients with combined CTU and contrast-enhanced CTDR. Compared with CTU alone, the combined technique of 3D CTU and contrast-enhanced CTDR improved opacification by a statistically significant difference (p = 0.037). CTU with 3D rendering can accurately depict both normal and abnormal postoperative findings in patients with urinary diversions. Adding enhanced CTDR can improve visualization of the urinary collecting system.

The association between gastroesophageal flap valve function and gastroesophageal reflux symptoms.

PubMed

Keskin, O; Kalkan, Ç; Yaman, A; Tüzün, A; Soykan, I

2017-01-01

Upper gastrointestinal endoscopic examination is usually the first step in the evaluation of patients with suspected gastroesopageal reflux disease. The primary aim of this study was to investigate the association between gastroesophageal flap valve function (GEFV) and gastroesophapgeal reflux symptoms in patients undergoing routine upper endoscopy. Patients and methods: 1507 patients were included into the study and the GEFV graded I to IV as follows: Hill I-II: normal GEFV, and Hill III-IV: abnormal GEFV. Patients in abnormal GEFV group had a higher incidence of reflux symptoms compared to normal GEFV group (53.4% vs 47.4% for heartburn p=0.03 and 53.2% vs 42.4% for regurgitation, p<0.01). In abnormal GEFV patients, esophagitis was more common compared to those with normal GEFV (32.6% vs 11.1%, p<0.01). Presence of heartburn and regurgitation (n =556) correlated with Hill III-IV grades (n = 184/556), (sensitivity: 33%, p = 0.003). In contrast, 24.6% (157/638) of patients without reflux symptoms were in abnormal GEFV group. In patients undergoing endoscopy because of reflux symptoms, Grade III-IV valve was detected more commonly in patients with reflux symptoms compared to patients without reflux symptoms (p = 0.01). Patients with abnormal valves (Hill grades III and IV) but without reflux symptoms, esophagitis and hiatal hernia should be evaluated individually by means of the presence of gastroesophageal reflux disease which means that GEFV is not a good indicator of reflux disease. © Acta Gastro-Enterologica Belgica.

Ocular motor characteristics of different subtypes of spinocerebellar ataxia: distinguishing features.

PubMed

Kim, Ji Sun; Kim, Ji Soo; Youn, Jinyoung; Seo, Dae-Won; Jeong, Yuri; Kang, Ji-Hoon; Park, Jeong Ho; Cho, Jin Whan

2013-08-01

Because of frequent involvement of the cerebellum and brainstem, ocular motor abnormalities are key features of spinocerebellar ataxias and may aid in differential diagnosis. Our objective for this study was to distinguish the subtypes by ophthalmologic features after head-shaking and positional maneuvers, which are not yet recognized as differential diagnostic tools in most common forms of spinocerebellar ataxias. Of the 302 patients with a diagnosis of cerebellar ataxia in 3 Korean University Hospitals from June 2011 to June 2012, 48 patients with spinocerebellar ataxia types 1, 2, 3, 6, 7, or 8 or with undetermined spinocerebellar ataxias were enrolled. All patients underwent a video-oculographic recording of fixation abnormalities, gaze-evoked nystagmus, positional and head-shaking nystagmus, and dysmetric saccades. Logistic regression analysis controlling for disease duration revealed that spontaneous and positional downbeat nystagmus and perverted head-shaking nystagmus were strong predictors for spinocerebellar ataxia 6, whereas saccadic intrusions and oscillations were identified as positive indicators of spinocerebellar ataxia 3. In contrast, the presence of gaze-evoked nystagmus and dysmetric saccades was a negative predictor of spinocerebellar ataxia 2. Positional maneuvers and horizontal head shaking occasionally induced or augmented saccadic intrusions/oscillations in patients with spinocerebellar ataxia types 1, 2, and 3 and undetermined spinocerebellar ataxia. The results indicated that perverted head-shaking nystagmus may be the most sensitive parameter for SCA6, whereas saccadic intrusions/oscillations are the most sensitive for spinocerebellar ataxia 3. In contrast, a paucity of gaze-evoked nystagmus and dysmetric saccades is more indicative of spinocerebellar ataxia 2. Head-shaking and positional maneuvers aid in defining ocular motor characteristics in spinocerebellar ataxias. © 2013 Movement Disorder Society. Copyright © 2013 Movement Disorder Society.

Lack of sensitivity of measurements of Vd/Vt at rest and during exercise in detection of hemodynamically significant pulmonary vascular abnormalities in collagen vascular disease.

PubMed

Mohsenifar, Z; Tashkin, D P; Levy, S E; Bjerke, R D; Clements, P J; Furst, D

1981-05-01

Wasted ventilation fraction (Vd/Vt) normally declines substantially during exercise in persons without lung disease. Failure of Vd/Vt to decrease during exercise has been reported to be one of the earliest abnormalities in patients with dyspnea caused by pulmonary vaso-occlusive disease, suggesting that measurement of Vd/Vt at rest and during exercise are useful in the diagnosis of pulmonary vascular disorders. We studied pulmonary hemodynamic and Vd/Vt responses to exercise in 11 patients in the supine position with suspected pulmonary vascular involvement caused by progressive systemic sclerosis, systemic lupus erythematosus, or recurrent pulmonary emboli, 10 of whom had dyspnea at rest and/or on exertion. In contrast to previous reports of no change or an increase in Vd/Vt during exercise in patients with pulmonary vascular disease, we found Vd/Vt to decrease significantly during exercise in 8 of 9 patients in whom mean pulmonary artery pressures were abnormally elevated at rest and/or during exercise. Our findings suggest that normal responses of Vd/Vt to exercise do not exclude hemodynamically significant pulmonary vaso-occlusive disease.

Disorganization of white matter architecture in major depressive disorder: a meta-analysis of diffusion tensor imaging with tract-based spatial statistics.

PubMed

Chen, Guangxiang; Hu, Xinyu; Li, Lei; Huang, Xiaoqi; Lui, Su; Kuang, Weihong; Ai, Hua; Bi, Feng; Gu, Zhongwei; Gong, Qiyong

2016-02-24

White matter (WM) abnormalities have long been suspected in major depressive disorder (MDD). Tract-based spatial statistics (TBSS) studies have detected abnormalities in fractional anisotropy (FA) in MDD, but the available evidence has been inconsistent. We performed a quantitative meta-analysis of TBSS studies contrasting MDD patients with healthy control subjects (HCS). A total of 17 studies with 18 datasets that included 641 MDD patients and 581 HCS were identified. Anisotropic effect size-signed differential mapping (AES-SDM) meta-analysis was performed to assess FA alterations in MDD patients compared to HCS. FA reductions were identified in the genu of the corpus callosum (CC) extending to the body of the CC and left anterior limb of the internal capsule (ALIC) in MDD patients relative to HCS. Descriptive analysis of quartiles, sensitivity analysis and subgroup analysis further confirmed these findings. Meta-regression analysis revealed that individuals with more severe MDD were significantly more likely to have FA reductions in the genu of the CC. This study provides a thorough profile of WM abnormalities in MDD and evidence that interhemispheric connections and frontal-striatal-thalamic pathways are the most convergent circuits affected in MDD.

Role of "Sural Sparing" Pattern (Absent/Abnormal Median and Ulnar with Present Sural SNAP) Compared to Absent/Abnormal Median or Ulnar with Normal Sural SNAP in Acute Inflammatory Demyelinating Polyneuropathy.

PubMed

Surpur, Spurthi Sunil; Govindarajan, Raghav

2017-01-01

Sural sparing defined as absent/abnormal median sensory nerve action potential (SNAP) amplitude or absent/abnormal ulnar SNAP amplitude with a normal sural SNAP amplitude is thought to be a marker for inflammatory demyelinating polyneuropathies. If sural sparing pattern specifically defined as absent/abnormal median and ulnar SNAP amplitude with normal sural SNAP amplitude (AMUNS) is sensitive and specific when compared with either absent/abnormal median and normal sural (AMNS) or absent/abnormal ulnar and normal sural (AUNS) for acute inflammatory demyelinating polyneuropathy (AIDP), chronic inflammatory demyelinating polyneuropathy (CIDP), select non-diabetic axonopathies (AXPs), and diabetic neuropathies (DNs). Retrospective analysis from 2001 to 2010 on all newly diagnosed AIDP, CIDP, select non-diabetic AXP, and DN. There were 20 AIDP and 23 CIDP. Twenty AXP and 50 DN patients between 2009 and 2010 were included as controls. AMUNS was seen in 65% of AIDP, 39% CIDP compared with 10% of AXP and 6% for DN with sensitivity of 51%, specificity of 92%, whereas the specificity of AMNS/AUNS was 73% and its sensitivity was 58%. If a patient has AMUNS they are >12 times more likely to have AIDP ( p  < 0.001). Sural sparing is highly specific but not sensitive when compared with either AMNS or AUNS in AIDP but does not add to sensitivity or specificity in CIDP.

Feedback-related negativity in children with two subtypes of attention deficit hyperactivity disorder.

PubMed

Gong, Jingbo; Yuan, Jiajin; Wang, Suhong; Shi, Lijuan; Cui, Xilong; Luo, Xuerong

2014-01-01

The current model of ADHD suggests abnormal reward and punishment sensitivity, although differences in ADHD subgroups are unclear. This study aimed to investigate the effect of feedback valence (reward or punishment) and punishment magnitude (small or large) on Feedback-Related Negativity (FRN) and Late Positive Potential (LPP) in two subtypes of ADHD (ADHD-C and ADHD-I) compared to typically developing children (TD) during a children's gambling task. Children with ADHD-C (n = 16), children with ADHD-I (n = 15) and typically developing children (n = 15) performed a children's gambling task under three feedback conditions: large losses, small losses and gains. FRN and LPP components in brain potentials were recorded and analyzed. In TD children and children with ADHD-C, large loss feedback evoked more negative FRN amplitudes than small loss feedback, suggesting that brain sensitivity to the punishment and its magnitude is not impaired in children with ADHD-C. In contrast to these two groups, the FRN effect was absent in children with ADHD-I. The LPP amplitudes were larger in children with ADHD-C in comparison with those with ADHD-I, regardless of feedback valence and magnitude. Children with ADHD-C exhibit intact brain sensitivity to punishment similar to TD children. In contrast, children with ADHD-I are significantly impaired in neural sensitivity to the feedback stimuli and in particular, to punishment, compared to TD and ADHD-C children. Thus, FRN, rather than LPP, is a reliable index of the difference in reward and punishment sensitivity across different ADHD-subcategories.

Glenohumeral articular cartilage lesions: prospective comparison of non-contrast magnetic resonance imaging and findings at arthroscopy.

PubMed

Spencer, Brian A; Dolinskas, Carol A; Seymour, Peter A; Thomas, Stephen J; Abboud, Joseph A

2013-09-01

The purpose of this study was to assess the diagnostic sensitivity, specificity, accuracy, negative predictive value (NPV), positive predictive value (PPV), and test-retest reliability of magnetic resonance imaging (MRI) for detecting cartilage abnormalities of the glenohumeral joint in comparison with the gold standard of diagnostic arthroscopy. Forty-four patients with a preoperative non-contrast MRI study of their affected shoulder underwent arthroscopy by one surgeon for rotator cuff tendinopathy from 2009 to 2010. Articular cartilage defects were prospectively recorded and graded according to the International Cartilage Repair Society classification system at the time of arthroscopy. One year after surgery, the preoperative MRI were reviewed by a board-certified radiologist and the treating surgeon for articular cartilage defects of both the humeral head and the glenoid. Sensitivity, specificity, accuracy, and test-retest reliability were calculated. At arthroscopy, 43% of the shoulders were found to have articular cartilage defects. When the readers' findings were combined, the sensitivity of detecting humeral lesions on MRI was 32%; specificity, 80%; accuracy, 63%; PPV, 57%; and NPV, 66%. The sensitivity of detecting glenoid lesions was 31%; specificity, 86%; accuracy, 76%; PPV, 33%; and NPV, 85%. This study finds that the overall accuracy of MRI in detecting articular cartilage damage in patients with the clinical diagnosis of subacromial pathology is moderate. Level II, development of diagnostic criteria based on consecutive patients with universally applied reference "gold" standard. Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Metabolic Abnormalities Are Common among South American Hispanics Subjects with Normal Weight or Excess Body Weight: The CRONICAS Cohort Study

PubMed Central

Benziger, Catherine P.; Bernabé-Ortiz, Antonio; Gilman, Robert H.; Checkley, William; Smeeth, Liam; Málaga, Germán; Miranda, J. Jaime

2015-01-01

Objective We aimed to characterize metabolic status by body mass index (BMI) status. Methods The CRONICAS longitudinal study was performed in an age-and-sex stratified random sample of participants aged 35 years or older in four Peruvian settings: Lima (Peru’s capital, costal urban, highly urbanized), urban and rural Puno (both high-altitude), and Tumbes (costal semirural). Data from the baseline study, conducted in 2010, was used. Individuals were classified by BMI as normal weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2), and obese (≥30 kg/m2), and as metabolically healthy (0–1 metabolic abnormality) or metabolically unhealthy (≥2 abnormalities). Abnormalities included individual components of the metabolic syndrome, high-sensitivity C-reactive protein, and insulin resistance. Results A total of 3088 (age 55.6±12.6 years, 51.3% females) had all measurements. Of these, 890 (28.8%), 1361 (44.1%) and 837 (27.1%) were normal weight, overweight and obese, respectively. Overall, 19.0% of normal weight in contrast to 54.9% of overweight and 77.7% of obese individuals had ≥3 risk factors (p<0.001). Among normal weight individuals, 43.1% were metabolically unhealthy, and age ≥65 years, female, and highest socioeconomic groups were more likely to have this pattern. In contrast, only 16.4% of overweight and 3.9% of obese individuals were metabolically healthy and, compared to Lima, the rural and urban sites in Puno were more likely to have a metabolically healthier profile. Conclusions Most Peruvians with overweight and obesity have additional risk factors for cardiovascular disease, as well as a majority of those with a healthy weight. Prevention programs aimed at individuals with a normal BMI, and those who are overweight and obese, are urgently needed, such as screening for elevated fasting cholesterol and glucose. PMID:26599322

Metabolic Abnormalities Are Common among South American Hispanics Subjects with Normal Weight or Excess Body Weight: The CRONICAS Cohort Study.

PubMed

Benziger, Catherine P; Bernabé-Ortiz, Antonio; Gilman, Robert H; Checkley, William; Smeeth, Liam; Málaga, Germán; Miranda, J Jaime

2015-01-01

We aimed to characterize metabolic status by body mass index (BMI) status. The CRONICAS longitudinal study was performed in an age-and-sex stratified random sample of participants aged 35 years or older in four Peruvian settings: Lima (Peru's capital, costal urban, highly urbanized), urban and rural Puno (both high-altitude), and Tumbes (costal semirural). Data from the baseline study, conducted in 2010, was used. Individuals were classified by BMI as normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30 kg/m2), and as metabolically healthy (0-1 metabolic abnormality) or metabolically unhealthy (≥2 abnormalities). Abnormalities included individual components of the metabolic syndrome, high-sensitivity C-reactive protein, and insulin resistance. A total of 3088 (age 55.6±12.6 years, 51.3% females) had all measurements. Of these, 890 (28.8%), 1361 (44.1%) and 837 (27.1%) were normal weight, overweight and obese, respectively. Overall, 19.0% of normal weight in contrast to 54.9% of overweight and 77.7% of obese individuals had ≥3 risk factors (p<0.001). Among normal weight individuals, 43.1% were metabolically unhealthy, and age ≥65 years, female, and highest socioeconomic groups were more likely to have this pattern. In contrast, only 16.4% of overweight and 3.9% of obese individuals were metabolically healthy and, compared to Lima, the rural and urban sites in Puno were more likely to have a metabolically healthier profile. Most Peruvians with overweight and obesity have additional risk factors for cardiovascular disease, as well as a majority of those with a healthy weight. Prevention programs aimed at individuals with a normal BMI, and those who are overweight and obese, are urgently needed, such as screening for elevated fasting cholesterol and glucose.

[Normal anatomy and related pathological changes of shoulder on MRI].

PubMed

Zhu, Q; Katsuya, N

2000-04-01

To describe the normal anatomy and common abnormal changes of rotator cuff impingement and tears and recurrent anterior instability of shoulder joint in MRI pictures. MRI was compared in 285 patients with shoulder diseases and 20 patients with symptomatic shoulder diseases. On oblique coronal image, the supraspinatus presented moderate signal intensity and low signal intensity in its tendon-muscle conjunction ranging from the humeral head to the greater tuberosity. The MRI manifestations of impingement lesion of the rotator cuff were as follows: high signal intensity of tendons, changes of their shapes, retraction of tendon-muscle conjunction, and muscle atrophy with high signal intensity. On T1-weighted axial image, the anterior and posterior glenohumeral labrum, the long head biceps tendon were displayed in low signal intensity. The anterior labrum manifested a sharp triangle contour and the posterior labrum a round one. The whole four muscles of the rotator cuff manifested on oblique sagital image. However, it was of less value in detecting the abnormalities of the rotator cuff and the glenohumeral labrum on sagittal imaging. The sensitivity in demonstrating rotator cuff complete tear was 95% for MRI and 91% for arthrography; the specificity was 88% for MRI and 100% for arthrography. The sensitivity and specificity of MRI were 96% and 75% for detecting glenoid labrum abnormalities, and 78% and 88% for detecting labrum tear in anterior recurrent dislocation of the shoulder. Magnetic resonance imaging with its excellent contrast resolution in multiple anatomic planes allows noninvasive visualization of bone and soft tissues in the rotator cuff and labrum.

Clinical evaluation of the 3M Littmann Electronic Stethoscope Model 3200 in 150 cats.

PubMed

Blass, Keith A; Schober, Karsten E; Bonagura, John D; Scansen, Brian A; Visser, Lance C; Lu, Jennifer; Smith, Danielle N; Ward, Jessica L

2013-10-01

Detection of murmurs and gallops may help to identify cats with heart disease. However, auscultatory findings may be subject to clinically relevant observer variation. The objective of this study was to evaluate an electronic stethoscope (ES) in cats. We hypothesized that the ES would perform at least as well as a conventional stethoscope (CS) in the detection of abnormal heart sounds. One hundred and fifty consecutive cats undergoing echocardiography were enrolled prospectively. Cats were ausculted with a CS (WA Tycos Harvey Elite) by two observers, and heart sounds were recorded digitally using an ES (3M Littmann Stethoscope Model 3200) for off-line analysis. Echocardiography was used as the clinical standard method for validation of auscultatory findings. Additionally, digital recordings (DRs) were assessed by eight independent observers with various levels of expertise, and compared using interclass correlation and Cohen's weighted kappa analyses. Using the CS, a heart murmur (n = 88 cats) or gallop sound (n = 17) was identified in 105 cats, whereas 45 cats lacked abnormal heart sounds. There was good total agreement (83-90%) between the two observers using the CS. In contrast, there was only moderate agreement (P <0.001) between results from the CS and the DRs for murmurs, and poor agreement for gallops. The CS was more sensitive compared with the DRs with regard to murmurs and gallops. Agreement among the eight observers was good-to-excellent for murmur detection (81%). In conclusion, DRs made with the ES are less sensitive but comparably specific to a CS at detecting abnormal heart sounds in cats.

Pitfalls in the detection of cholesterol in Huntington’s disease models

PubMed Central

Marullo, Manuela; Valenza, Marta; Leoni, Valerio; Caccia, Claudio; Scarlatti, Chiara; De Mario, Agnese; Zuccato, Chiara; Di Donato, Stefano; Carafoli, Ernesto; Cattaneo, Elena

2012-01-01

Background Abnormalities in brain cholesterol homeostasis have been reported in Huntington’s disease (HD), an adult-onset neurodegenerative disorder caused by an expansion in the number of CAG repeats in the huntingtin (HTT) gene. However, the results have been contradictory with respect to whether cholesterol levels increase or decrease in HD models. Biochemical and mass spectrometry methods show reduced levels of cholesterol precursors and cholesterol in HD cells and in the brains of several HD animal models. Abnormal brain cholesterol homeostasis was also inferred from studies in HD patients. In contrast, colorimetric and enzymatic methods indicate cholesterol accumulation in HD cells and tissues. Here we used several methods to investigate cholesterol levels in cultured cells in the presence or absence of mutant HTT protein. Results Colorimetric and enzymatic methods with low sensitivity gave variable results, whereas results from a sensitive analytical method, gas chromatography-mass spectrometry, were more reliable. Sample preparation, high cell density and cell clonality also influenced the detection of intracellular cholesterol. Conclusions Detection of cholesterol in HD samples by colorimetric and enzymatic assays should be supplemented by detection using more sensitive analytical methods. Care must be taken to prepare the sample appropriately. By evaluating lathosterol levels using isotopic dilution mass spectrometry, we confirmed reduced cholesterol biosynthesis in knock-in cells expressing the polyQ mutation in a constitutive or inducible manner. *Correspondence should be addressed to Elena Cattaneo: elena.cattaneo@unimi.it PMID:23145355

Basilar artery hypoplasia associated with changes of brainstem potential, transcranial Doppler and perfusion-weighted imaging.

PubMed

Zhang, Dao Pei; Yin, Suo; Zhang, Shu Ling; Zhang, Jie Wen; Ma, Qian Kun; Lu, Gui Feng

2017-07-01

The aim of this study was to observe brainstem hemodynamic alterations associated with basilar artery hypoplasia (BAH). Nine hundred and fifty-two consecutive patients received emergency multimodal computed tomography; magnetic resonance imaging and magnetic resonance angiogram during the period of January 2011 to December 2014 were included. The vascular risk factors, brainstem auditory evoked potential (BAEP), blink reflex (BR), transcranial Doppler (TCD) and dynamic susceptibility contrast-enhanced perfusion-weighted imaging were completed. There was significant difference in the abnormal rates of TCD and BAEP between BAH and non-BAH patients. A positive correlation between basilar artery diameter and systolic velocity among BAH patients was suggested. V-wave value was used to predict posterior circulation infarction (PCI) with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 5.97 s. Abnormal BR rate was also significantly different in BAH and non-BAH patients. The latency of R2 was used to predict PCI with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 46.4 ms. The incidence of hypoperfusion was higher in BAH than non-BAH group and it was significant difference. BAH is closely associated with hemodynamic alterations within the pons, which might contribute to vascular vertigo due to regional hypoperfusion.

Xeroderma pigmentosum neurological abnormalities correlate with colony-forming ability after ultraviolet radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, A.D.; Barrett, S.F.; Robbins, J.H.

1978-04-01

Xeroderma pigmentosum is an autosomal recessive disease in which DNA repair processes are defective. All xeroderma pigmentosum patients develop premature aging of sun exposed skin, and some develop neurological abnormalities due to premature death of nerve cells. Sensitivity to ultraviolet radiation of 24 xeroderma pigmentosum fibroblast strains was studied in vitro by measuring each strain's ability to divide and form colonies after irradiation. The most sensitive strains were derived from patients who had an early onset of neurological abnormalities; less sensitive strains were from patients with a later onset; and the most resistant strains were from patients without neurological abnormalities.more » The uv sensitivities of strains from each member of a sibling pair with xeroderma pigmentosum were identical, indicating that uv sensitivity of xeroderma pigmentosum strains is determined by the patient's inherited DNA repair defect. The results suggest that effective DNA repair is required to maintain the functional integrity of the human nervous system by preventing premature death of neurons.« less

Physiology of leptin: energy homeostasis, neuroendocrine function and metabolism.

PubMed

Park, Hyeong-Kyu; Ahima, Rexford S

2015-01-01

Leptin is secreted by adipose tissue and regulates energy homeostasis, neuroendocrine function, metabolism, immune function and other systems through its effects on the central nervous system and peripheral tissues. Leptin administration has been shown to restore metabolic and neuroendocrine abnormalities in individuals with leptin-deficient states, including hypothalamic amenorrhea and lipoatrophy. In contrast, obese individuals are resistant to leptin. Recombinant leptin is beneficial in patients with congenital leptin deficiency or generalized lipodystrophy. However, further research on molecular mediators of leptin resistance is needed for the development of targeted leptin sensitizing therapies for obesity and related metabolic diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

Physiologic study of the terminal digestive tract in chronic painful constipation.

PubMed Central

Meunier, P

1986-01-01

A manometric study of the sigmoid colon and of the anorectum was undertaken in 65 chronically constipated patients complaining of abdominal pain, and in a control group of 23 healthy volunteers. Rectal compliance was tested in both groups. The sigmoid motility study allowed for the segregation of the constipated patients into three groups: hypokinesia (12 cases), normokinesia (34 cases), hyperkinesia (19 cases). Rectal manometry showed anal hypertony in 24 patients, impaired rectal conscious sensitivity in 12 subjects, and normal functions in the remaining cases. The rectal compliance study disclosed a decreased compliance in 15 cases and increased compliance in 13 other patients. In 12 cases disordered sigmoid motility was the only abnormality; in 10 cases only a rectoanal abnormality was found. Most of the patients (52%) exhibited miscellaneous disorders. In contrast, all parameters were normal in nine subjects. No consistent pattern of motility disorders was thus demonstrated in this clinically homogeneous group of patients with chronic, painful, constipation. PMID:3758814

Analysis of light emitting diode array lighting system based on human vision: normal and abnormal uniformity condition.

PubMed

Qin, Zong; Ji, Chuangang; Wang, Kai; Liu, Sheng

2012-10-08

In this paper, condition for uniform lighting generated by light emitting diode (LED) array was systematically studied. To take human vision effect into consideration, contrast sensitivity function (CSF) was novelly adopted as critical criterion for uniform lighting instead of conventionally used Sparrow's Criterion (SC). Through CSF method, design parameters including system thickness, LED pitch, LED's spatial radiation distribution and viewing condition can be analytically combined. In a specific LED array lighting system (LALS) with foursquare LED arrangement, different types of LEDs (Lambertian and Batwing type) and given viewing condition, optimum system thicknesses and LED pitches were calculated and compared with those got through SC method. Results show that CSF method can achieve more appropriate optimum parameters than SC method. Additionally, an abnormal phenomenon that uniformity varies with structural parameters non-monotonically in LALS with non-Lambertian LEDs was found and analyzed. Based on the analysis, a design method of LALS that can bring about better practicability, lower cost and more attractive appearance was summarized.

New Perspectives in Amblyopia Therapy on Adults: A Critical Role for the Excitatory/Inhibitory Balance

PubMed Central

Baroncelli, Laura; Maffei, Lamberto; Sale, Alessandro

2011-01-01

Amblyopia is the most common form of impairment of visual function affecting one eye, with a prevalence of about 1–5% of the total world population. This pathology is caused by early abnormal visual experience with a functional imbalance between the two eyes owing to anisometropia, strabismus, or congenital cataract, resulting in a dramatic loss of visual acuity in an apparently healthy eye and various other perceptual abnormalities, including deficits in contrast sensitivity and in stereopsis. It is currently accepted that, due to a lack of sufficient plasticity within the brain, amblyopia is untreatable in adulthood. However, recent results obtained both in clinical trials and in animal models have challenged this traditional view, unmasking a previously unsuspected potential for promoting recovery after the end of the critical period for visual cortex plasticity. These studies point toward the intracortical inhibitory transmission as a crucial brake for therapeutic rehabilitation and recovery from amblyopia in the adult brain. PMID:22144947

Max CAPR: high-resolution 3D contrast-enhanced MR angiography with acquisition times under 5 seconds.

PubMed

Haider, Clifton R; Borisch, Eric A; Glockner, James F; Mostardi, Petrice M; Rossman, Phillip J; Young, Phillip M; Riederer, Stephen J

2010-10-01

High temporal and spatial resolution is desired in imaging of vascular abnormalities having short arterial-to-venous transit times. Methods that exploit temporal correlation to reduce the observed frame time demonstrate temporal blurring, obfuscating bolus dynamics. Previously, a Cartesian acquisition with projection reconstruction-like (CAPR) sampling method has been demonstrated for three-dimensional contrast-enhanced angiographic imaging of the lower legs using two-dimensional sensitivity-encoding acceleration and partial Fourier acceleration, providing 1mm isotropic resolution of the calves, with 4.9-sec frame time and 17.6-sec temporal footprint. In this work, the CAPR acquisition is further undersampled to provide a net acceleration approaching 40 by eliminating all view sharing. The tradeoff of frame time and temporal footprint in view sharing is presented and characterized in phantom experiments. It is shown that the resultant 4.9-sec acquisition time, three-dimensional images sets have sufficient spatial and temporal resolution to clearly portray arterial and venous phases of contrast passage. It is further hypothesized that these short temporal footprint sequences provide diagnostic quality images. This is tested and shown in a series of nine contrast-enhanced MR angiography patient studies performed with the new method.

Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

NASA Astrophysics Data System (ADS)

Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.

2016-06-01

Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations.

Sensitivity and specificity of western blot testing of cerebrospinal fluid and serum for diagnosis of equine protozoal myeloencephalitis in horses with and without neurologic abnormalities.

PubMed

Daft, Barbara M; Barr, Bradd C; Gardner, Ian A; Read, Deryck; Bell, William; Peyser, Karen G; Ardans, Alex; Kinde, Hailu; Morrow, Jennifer K

2002-10-01

To determine sensitivity and specificity of western blot testing (WBT) of CSF and serum for diagnosis of equine protozoal myeloencephalitis (EPM) in horses with and without neurologic abnormalities. Prospective investigation. 65 horses with and 169 horses without neurologic abnormalities. CSF and serum from horses submitted for necropsy were tested for Sarcocystis neurona-specific antibody with a WBT. Results of postmortem examination were used as the gold standard against which results of the WBT were compared. Sensitivity of WBT of CSF was 87% for horses with and 88% for horses without neurologic abnormalities. Specificity of WBT of CSF was 44% for horses with and 60% for horses without neurologic abnormalities. Regardless of whether horses did or did not have neurologic abnormalities, sensitivity and specificity of WBT of serum were not significantly different from values for WBT of CSF. Ninety-four horses without EPM had histologic evidence of slight CNS inflammation. The low specificity of WBT of CSF indicated that it is inappropriate to diagnose EPM on the basis of a positive test result alone because of the possibility of false-positive test results. The high sensitivity, however, means that a negative result is useful in ruling out EPM. There was no advantage in testing CSF versus serum in horses without neurologic abnormalities. Slight CNS inflammation was common in horses with and without S neurona-specific antibodies in the CSF and should not be considered an indication of CNS infection with S neurona.

Classification of cardiac-related artifacts in dynamic contrast breast MRI

NASA Astrophysics Data System (ADS)

Stegbauer, Keith C.; Smith, Justin P.; Niemeyer, Tanya L.; Wood, Chris

2004-05-01

Dynamic contrast breast MRI is becoming an important adjunct in screening women at high risk for breast cancer, determining extent of disease (staging) and monitoring response to therapy. In dynamic contrast breast MRI, regions of rapid contrast uptake indicate increases in vascularity which can be associated with abnormal tissue, sometimes significant for malignant disease. To show these areas of enhancement, subtractions between the pre and post contrast images and maximum intensity projections (MIPs) are computed. Many projections are obscured by normally enhancing anatomy (heart, aorta, pulmonary vessels). Identification of these structures allows their removal from MIPs, which improves image quality, diagnostic utility and the conspicuity of the enhancing regions. In this study, a fully automated classifier is presented which uses the spatial location of enhancing regions to separate those that occur inside the chest wall from those occurring in the tissue of interest (breast, axilla, chest wall). The classifier was trained on 21 studies each acquired at a different institution (699 clusters of pixels), and tested on 7 studies (231 clusters of pixels) that were not part of the training set. Multiple cost functions for training were examined. The measurements for the peak performance of the classifier were sensitivity 97.0%, specificity 99.4%, PPV 99.9%, NPV 78.8%.

Low-dose computed tomography in assessment of pulmonary abnormalities in children with febrile neutropenia suffering from malignant diseases.

PubMed

Zaleska-Dorobisz, Urszula; Olchowy, Cyprian; Łasecki, Mateusz; Sokołowska-Dąbek, Dąbrówka; Pawluś, Aleksander; Frączkiewicz, Jowita; Gorczyńska, Ewa

2017-07-01

Management of febrile neutropenia in pediatric patients is challenging. Chest X-ray and CT scan help to identify infective foci; however, exposure to radiation is a risk factor for development of secondary cancer. For this reason, attention is paid to reducing radiation exposure. The aim of the study was to define the role of LDCT examination in the early detection of pulmonary lesions in children during oncology or autoimmune treatment complicated by neutropenia-related fever. Additionally, we focused on the possibility to optimize image quality in low-dose protocols. The study included 138 pediatric patients (mean age 8.08 years) with fever of 38.2°C or higher with an absolute neutrophil count of 10 mm with or without surrounding GGO or cavitations was sensitive at 77% and specific at 65% for fungal infection insert after neutrophil count: < 500/pL who underwent chest X-ray and LDCT in the maximal interval of 24 h. CT findings were compared with initial and final diagnosis as well as with clinical information. LDCT detected pulmonary abnormalities in 116 patients (84.06%) showing ground-glass opacities (GGO) (n = 79), nodules (n = 60) and air-space consolidations (n = 58). Radiologists correctly diagnosed infective lesions in 94 out of 116 patients (81.03%). The presence of random or pleural-based nodules. Diagnosis of pyogenic infection based on the presence of air-space consolidation, pleural effusion, GGO or centrilobular nodules showed a sensitivity of 78% and specificity of 67%, whereas patchy or diffuse GGO, interstitial thickening and/or air-space consolidation showed a high sensitivity of 81% and specificity of 68% for Pneumocystis jirovecii pneumonia. LDCT is an excellent modality in the diagnostic algorithm in patients with febrile neutropenia. It allows early detection and detailed characterization of pulmonary abnormalities. Using contrast, unenhanced CT examinations can further reduce radiation dose and diminish the number of complications without a negative influence on the diagnostic process.

Nanoparticle imaging probes for molecular imaging with computed tomography and application to cancer imaging

NASA Astrophysics Data System (ADS)

Roeder, Ryan K.; Curtis, Tyler E.; Nallathamby, Prakash D.; Irimata, Lisa E.; McGinnity, Tracie L.; Cole, Lisa E.; Vargo-Gogola, Tracy; Cowden Dahl, Karen D.

2017-03-01

Precision imaging is needed to realize precision medicine in cancer detection and treatment. Molecular imaging offers the ability to target and identify tumors, associated abnormalities, and specific cell populations with overexpressed receptors. Nuclear imaging and radionuclide probes provide high sensitivity but subject the patient to a high radiation dose and provide limited spatiotemporal information, requiring combined computed tomography (CT) for anatomic imaging. Therefore, nanoparticle contrast agents have been designed to enable molecular imaging and improve detection in CT alone. Core-shell nanoparticles provide a powerful platform for designing tailored imaging probes. The composition of the core is chosen for enabling strong X-ray contrast, multi-agent imaging with photon-counting spectral CT, and multimodal imaging. A silica shell is used for protective, biocompatible encapsulation of the core composition, volume-loading fluorophores or radionuclides for multimodal imaging, and facile surface functionalization with antibodies or small molecules for targeted delivery. Multi-agent (k-edge) imaging and quantitative molecular imaging with spectral CT was demonstrated using current clinical agents (iodine and BaSO4) and a proposed spectral library of contrast agents (Gd2O3, HfO2, and Au). Bisphosphonate-functionalized Au nanoparticles were demonstrated to enhance sensitivity and specificity for the detection of breast microcalcifications by conventional radiography and CT in both normal and dense mammary tissue using murine models. Moreover, photon-counting spectral CT enabled quantitative material decomposition of the Au and calcium signals. Immunoconjugated Au@SiO2 nanoparticles enabled highly-specific targeting of CD133+ ovarian cancer stem cells for contrast-enhanced detection in model tumors.

Silver nanoparticles induce developmental stage-specific embryonic phenotypes in zebrafish.

PubMed

Lee, Kerry J; Browning, Lauren M; Nallathamby, Prakash D; Osgood, Christopher J; Xu, Xiao-Hong Nancy

2013-12-07

Much is anticipated from the development and deployment of nanomaterials in biological organisms, but concerns remain regarding their biocompatibility and target specificity. Here we report our study of the transport, biocompatibility and toxicity of purified and stable silver nanoparticles (Ag NPs, 13.1 ± 2.5 nm in diameter) upon the specific developmental stages of zebrafish embryos using single NP plasmonic spectroscopy. We find that single Ag NPs passively diffuse into five different developmental stages of embryos (cleavage, early-gastrula, early-segmentation, late-segmentation, and hatching stages), showing stage-independent diffusion modes and diffusion coefficients. Notably, the Ag NPs induce distinctive stage and dose-dependent phenotypes and nanotoxicity, upon their acute exposure to the Ag NPs (0-0.7 nM) for only 2 h. The late-segmentation embryos are most sensitive to the NPs with the lowest critical concentration (CNP,c < 0.02 nM) and highest percentages of cardiac abnormalities, followed by early-segmentation embryos (CNP,c < 0.02 nM), suggesting that disruption of cell differentiation by the NPs causes the most toxic effects on embryonic development. The cleavage-stage embryos treated with the NPs develop into a wide variety of phenotypes (abnormal finfold, tail/spinal cord flexure, cardiac malformation/edema, yolk sac edema, and acephaly). These organ structures are not yet developed in cleavage-stage embryos, suggesting that the earliest determinative events to create these structures are ongoing, and disrupted by NPs, which leads to the downstream effects. In contrast, the hatching embryos are most resistant to the Ag NPs, and majority of embryos (94%) develop normally, and none of them develop abnormally. Interestingly, early-gastrula embryos are less sensitive to the NPs than cleavage and segmentation stage embryos, and do not develop abnormally. These important findings suggest that the Ag NPs are not simple poisons, and they can target specific pathways in development, and potentially enable target specific study and therapy for early embryonic development.

Beryllium sensitization and disease among long-term and short-term workers in a beryllium ceramics plant.

PubMed

Henneberger, P K; Cumro, D; Deubner, D D; Kent, M S; McCawley, M; Kreiss, K

2001-04-01

Workers at a beryllium ceramics plant were tested for beryllium sensitization and disease in 1998 to determine whether the plant-wide prevalence of sensitization and disease had declined since the last screening in 1992; an elevated prevalence was associated with specific processes or with high exposures; exposure-response relationships differed for long-term workers hired before the last plant-wide screening and short-term workers hired since then. Current workers were asked to complete a questionnaire and to provide blood for the beryllium lymphocyte proliferation test (BeLPT). Those with an abnormal BeLPT were classified as sensitized, and were offered clinical evaluation for beryllium disease. Task- and time-specific measurements of airborne beryllium were combined with individual work histories to compute mean, cumulative, and peak beryllium exposures for each worker. The 151 participants represented 90% of 167 eligible workers. Fifteen (9.9% of 151) had an abnormal BeLPT and were split between long-term workers (8/77 = 10.4%) and short-term workers (7/74 = 9.5%). Beryllium disease was detected in 9.1% (7/77) of long-term workers but in only 1.4% (1/74) of short-term workers (P = 0.06), for an overall prevalence of 5.3% (8/151). These prevalences were similar to those observed in the earlier survey. The prevalence of sensitization was elevated in 1992 among machinists, and was still elevated in 1998 among long-term workers (7/40 = 18%) but not among short-term workers (2/36 = 6%) with machining experience. The prevalence of sensitization was also elevated in both groups of workers for the processes of lapping, forming, firing, and packaging. The data suggested a positive relationship between peak beryllium exposure and sensitization for long-term workers and between mean, cumulative, and peak exposure and sensitization for short-term workers, although these findings were not statistically significant. Long-term workers with either a high peak exposure or work experience in forming were more likely to have an abnormal BeLPT (8/51 = 16%) than the other long-term workers (0/26, P = 0.05). All seven sensitized short-term workers either had high mean beryllium exposure or had worked longest in forming or machining (7/55 = 13% versus 0/19, P = 0.18). A plant-wide decline in beryllium exposures between the 1992 and 1998 surveys was not matched by a decline in the prevalence of sensitization and disease. Similar to findings from other studies, beryllium sensitization/disease was associated with specific processes and elevated exposures. The contrast in disease prevalence between long-term and short-term workers suggests that beryllium sensitization can occur after a short period of exposure, but beryllium disease usually requires a longer latency and/or period of exposure. The findings from this study motivated interventions to more aggressively protect and test workers, and new research into skin exposure as a route of sensitization and the contribution of individual susceptibility.

Feeling Abnormal: Simulation of Deviancy in Abnormal and Exceptionality Courses.

ERIC Educational Resources Information Center

Fernald, Charles D.

1980-01-01

Describes activity in which student in abnormal psychology and psychology of exceptional children classes personally experience being judged abnormal. The experience allows the students to remember relevant research, become sensitized to the feelings of individuals classified as deviant, and use caution in classifying individuals as abnormal.…

Detectability of early brain meningitis with magnetic resonance imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Runge, V.M.; Wells, J.W.; Williams, N.M.

1995-08-01

The ability of high-field (1.5 T) magnetic resonance imaging (MRI) to detect early brain meningitis was evaluated in a canine model. Contrast dose, timing postinjection, and imaging technique (specifically the use of magnetization transfer) were assessed. Imaging of five canines was performed at 1.5 T 24 hours after injection of Cowans staphylococcus into the cisterna magna. Two control animals also were imaged using the same protocol. Contrast doses of 0.1, 0.3, and 0.8 mmol/kg gadoteridol were compared. Scans were performed at 2, 13, and 22 minutes after an initial injection of 0.1 mmol/kg. Thirty minutes after the initial injection ofmore » contrast, a supplemental dose of 0.2 mmol/kg was given. Scans were then repeated at 2, 12, and 22 minutes after this dose was administered. A second supplemental contrast injection of 0.5 mmol/kg was given at 70 minutes, and immediate postinjection scans with and without MT were acquired. Results. In the animals receiving a cisternal injection of bacteria, the degree of meningeal enhancement was greatest at 0.8 mmol/kg, intermediate at 0.3 mmol/kg, and least at 0.1 mmol/kg. Scans in control studies did not demonstrate abnormal meningeal enhancement. High-contrast dose, MT, and acquisition of immediate postcontrast scans all resulted in statistically significant improvement. On masked film review, abnormal meningeal enhancement was noted in only 2 of 5 experimental dogs at a dose of 0.1 mmol/kg (regardless of the use of MT) compared with all animals at a dose of 0.3 mmol/kg. In 18 of 37 dogs (paired scans with and without MT), when abnormal enhancement was noted, the use of MT improved the visualization of abnormal meningeal enhancement. In early brain meningitis, high-contrast dose (0.3 mmol/kg), MT, and scanning immediately after injection improve detection of abnormal meningeal enhancement, thus facilitating the diagnosis of meningitis. Of these factors, contrast dose is the most important. 14 refs., 9 figs., 2 tabs.« less

The Objective Identification and Quantification of Interstitial Lung Abnormalities in Smokers.

PubMed

Ash, Samuel Y; Harmouche, Rola; Ross, James C; Diaz, Alejandro A; Hunninghake, Gary M; Putman, Rachel K; Onieva, Jorge; Martinez, Fernando J; Choi, Augustine M; Lynch, David A; Hatabu, Hiroto; Rosas, Ivan O; Estepar, Raul San Jose; Washko, George R

2017-08-01

Previous investigation suggests that visually detected interstitial changes in the lung parenchyma of smokers are highly clinically relevant and predict outcomes, including death. Visual subjective analysis to detect these changes is time-consuming, insensitive to subtle changes, and requires training to enhance reproducibility. Objective detection of such changes could provide a method of disease identification without these limitations. The goal of this study was to develop and test a fully automated image processing tool to objectively identify radiographic features associated with interstitial abnormalities in the computed tomography scans of a large cohort of smokers. An automated tool that uses local histogram analysis combined with distance from the pleural surface was used to detect radiographic features consistent with interstitial lung abnormalities in computed tomography scans from 2257 individuals from the Genetic Epidemiology of COPD study, a longitudinal observational study of smokers. The sensitivity and specificity of this tool was determined based on its ability to detect the visually identified presence of these abnormalities. The tool had a sensitivity of 87.8% and a specificity of 57.5% for the detection of interstitial lung abnormalities, with a c-statistic of 0.82, and was 100% sensitive and 56.7% specific for the detection of the visual subtype of interstitial abnormalities called fibrotic parenchymal abnormalities, with a c-statistic of 0.89. In smokers, a fully automated image processing tool is able to identify those individuals who have interstitial lung abnormalities with moderate sensitivity and specificity. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Fricative Contrast and Coarticulation in Children With and Without Speech Sound Disorders

PubMed Central

Mailend, Marja-Liisa

2017-01-01

Purpose The purpose of this study was, first, to expand our understanding of typical speech development regarding segmental contrast and anticipatory coarticulation, and second, to explore the potential diagnostic utility of acoustic measures of fricative contrast and anticipatory coarticulation in children with speech sound disorders (SSD). Method In a cross-sectional design, 10 adults, 17 typically developing children, and 11 children with SSD repeated carrier phrases with novel words with fricatives (/s/, /ʃ/). Dependent measures were 2 ratios derived from spectral mean, obtained from perceptually accurate tokens. Group analyses compared adults and typically developing children; individual children with SSD were compared to their respective typically developing peers. Results Typically developing children demonstrated smaller fricative acoustic contrast than adults but similar coarticulatory patterns. Three children with SSD showed smaller fricative acoustic contrast than their typically developing peers, and 2 children showed abnormal coarticulation. The 2 children with abnormal coarticulation both had a clinical diagnosis of childhood apraxia of speech; no clear pattern was evident regarding SSD subtype for smaller fricative contrast. Conclusions Children have not reached adult-like speech motor control for fricative production by age 10 even when fricatives are perceptually accurate. Present findings also suggest that abnormal coarticulation but not reduced fricative contrast is SSD-subtype–specific. Supplemental Materials S1: https://doi.org/10.23641/asha.5103070. S2 and S3: https://doi.org/10.23641/asha.5106508 PMID:28654946

Automatic Detection of Lung and Liver Lesions in 3-D Positron Emission Tomography Images: A Pilot Study

NASA Astrophysics Data System (ADS)

Lartizien, Carole; Marache-Francisco, Simon; Prost, Rémy

2012-02-01

Positron emission tomography (PET) using fluorine-18 deoxyglucose (18F-FDG) has become an increasingly recommended tool in clinical whole-body oncology imaging for the detection, diagnosis, and follow-up of many cancers. One way to improve the diagnostic utility of PET oncology imaging is to assist physicians facing difficult cases of residual or low-contrast lesions. This study aimed at evaluating different schemes of computer-aided detection (CADe) systems for the guided detection and localization of small and low-contrast lesions in PET. These systems are based on two supervised classifiers, linear discriminant analysis (LDA) and the nonlinear support vector machine (SVM). The image feature sets that serve as input data consisted of the coefficients of an undecimated wavelet transform. An optimization study was conducted to select the best combination of parameters for both the SVM and the LDA. Different false-positive reduction (FPR) methods were evaluated to reduce the number of false-positive detections per image (FPI). This includes the removal of small detected clusters and the combination of the LDA and SVM detection maps. The different CAD schemes were trained and evaluated based on a simulated whole-body PET image database containing 250 abnormal cases with 1230 lesions and 250 normal cases with no lesion. The detection performance was measured on a separate series of 25 testing images with 131 lesions. The combination of the LDA and SVM score maps was shown to produce very encouraging detection performance for both the lung lesions, with 91% sensitivity and 18 FPIs, and the liver lesions, with 94% sensitivity and 10 FPIs. Comparison with human performance indicated that the different CAD schemes significantly outperformed human detection sensitivities, especially regarding the low-contrast lesions.

Automated detection of nerve fiber layer defects on retinal fundus images using fully convolutional network for early diagnosis of glaucoma

NASA Astrophysics Data System (ADS)

Watanabe, Ryusuke; Muramatsu, Chisako; Ishida, Kyoko; Sawada, Akira; Hatanaka, Yuji; Yamamoto, Tetsuya; Fujita, Hiroshi

2017-03-01

Early detection of glaucoma is important to slow down progression of the disease and to prevent total vision loss. We have been studying an automated scheme for detection of a retinal nerve fiber layer defect (NFLD), which is one of the earliest signs of glaucoma on retinal fundus images. In our previous study, we proposed a multi-step detection scheme which consists of Gabor filtering, clustering and adaptive thresholding. The problems of the previous method were that the number of false positives (FPs) was still large and that the method included too many rules. In attempt to solve these problems, we investigated the end-to-end learning system without pre-specified features. A deep convolutional neural network (DCNN) with deconvolutional layers was trained to detect NFLD regions. In this preliminary investigation, we investigated effective ways of preparing the input images and compared the detection results. The optimal result was then compared with the result obtained by the previous method. DCNN training was carried out using original images of abnormal cases, original images of both normal and abnormal cases, ellipse-based polar transformed images, and transformed half images. The result showed that use of both normal and abnormal cases increased the sensitivity as well as the number of FPs. Although NFLDs are visualized with the highest contrast in green plane, the use of color images provided higher sensitivity than the use of green image only. The free response receiver operating characteristic curve using the transformed color images, which was the best among seven different sets studied, was comparable to that of the previous method. Use of DCNN has a potential to improve the generalizability of automated detection method of NFLDs and may be useful in assisting glaucoma diagnosis on retinal fundus images.

Characteristic MRI findings in hyperglycaemia-induced seizures: diagnostic value of contrast-enhanced fluid-attenuated inversion recovery imaging.

PubMed

Lee, E J; Kim, K K; Lee, E K; Lee, J E

2016-12-01

To describe characteristic magnetic resonance imaging (MRI) abnormalities in hyperglycaemia-induced seizures, and evaluate the diagnostic value of contrast-enhanced fluid-attenuated inversion recovery (FLAIR) imaging. Possible underlying mechanisms of this condition are also discussed. Eleven patients with hyperglycaemia-induced seizures and MRI abnormalities were retrospectively studied. Clinical manifestations, laboratory findings, MRI findings, and clinical outcomes were analysed. All patients, except one, presented with focal seizures, simple or complex partial seizures, or negative motor seizures. All patients had long-standing uncontrolled diabetes mellitus. The MRI abnormalities observed acutely were focal subcortical hypointensities on T2-weighted imaging and FLAIR imaging in all patients with overlying cortical gyral T2 hyperintensities in five. Focal overlying cortical or leptomeningeal enhancement on contrast-enhanced T1-weighted imaging or contrast-enhanced FLAIR imaging was observed in all patients. Contrast-enhanced FLAIR imaging was superior to contrast-enhanced T1-weighted imaging for detecting characteristic cortical or leptomeningeal enhancement. Diffusion-weighted imaging showed mildly restricted diffusion in four of five patients with cortical gyral T2 hyperintensity. In nine patients, the lesions were localised in the parietal or parieto-occipital lobes. The other two patients showed localised precentral gyral lesions. After treatment, the neurological symptoms, including the seizures, improved in all patients. On clinical recovery, the subcortical T2 hypointensity, gyral or leptomeningeal enhancement, and overlying cortical T2 hyperintensities resolved. Recognition of these radiological abnormalities in patients with hyperglycaemia-induced seizures is important in restricting unwarranted investigations and initiating early therapy. These patients generally have a good prognosis. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

The value of ultrasound and magnetic resonance imaging in diagnostics and prediction of morbidity in cases of placenta previa with abnormal placentation.

PubMed

Algebally, Ahmed M; Yousef, Reda Ramadan Hussein; Badr, Sanaa Sayed Hussein; Al Obeidly, Amal; Szmigielski, Wojciech; Al Ibrahim, Abdullah A

2014-01-01

The purpose of the study was to evaluate the role of ultrasound (US) and magnetic resonance imaging (MRI) in the diagnostics and management of abnormal placentation in women with placenta previa and to compare the morbidity associated with that to placenta previa alone. The study includes 100 pregnant women with placenta previa with and without abnormal placentation. The results of MRI and US in abnormal placentation were compared with post-operative data. The patients' files were reviewed for assessment of operative and post-operative morbidity. The results of our statistical analysis were compared with data from the literature. US and MRI showed no significant difference in sensitivity and specificity in diagnosing abnormal placentation (97-100% and 94-100%, respectively). MRI was more sensitive than US for the detection of myometrial invasion and the type of abnormal placentation (73.5% and 47%, respectively). The difference between pre- and post-operative hemoglobin values and estimated blood loss were the most significant risk factors for abnormal placentation, added to risk factors known for placenta previa. Post-partum surgical complications and prolonged hospital stay were more common in the cases of placenta previa with abnormal placentation, however statistically insignificant. US and MRI are accurate imaging modalities for diagnosing abnormal placentation. MRI was more sensitive for the detection of the degree of placental invasion. The patient's morbidity increased in cases with abnormal placentation. There was no significant difference in post operative-complications and hospitalization time due to pre-operative planning when the diagnosis was established with US and MRI.

Contrast-enhanced spectral mammography improves diagnostic accuracy in the symptomatic setting.

PubMed

Tennant, S L; James, J J; Cornford, E J; Chen, Y; Burrell, H C; Hamilton, L J; Girio-Fragkoulakis, C

2016-11-01

To assess the diagnostic accuracy of contrast-enhanced spectral mammography (CESM), and gauge its "added value" in the symptomatic setting. A retrospective multi-reader review of 100 consecutive CESM examinations was performed. Anonymised low-energy (LE) images were reviewed and given a score for malignancy. At least 3 weeks later, the entire examination (LE and recombined images) was reviewed. Histopathology data were obtained for all cases. Differences in performance were assessed using receiver operator characteristic (ROC) analysis. Sensitivity, specificity, and lesion size (versus MRI or histopathology) differences were calculated. Seventy-three percent of cases were malignant at final histology, 27% were benign following standard triple assessment. ROC analysis showed improved overall performance of CESM over LE alone, with area under the curve of 0.93 versus 0.83 (p<0.025). CESM showed increased sensitivity (95% versus 84%, p<0.025) and specificity (81% versus 63%, p<0.025) compared to LE alone, with all five readers showing improved accuracy. Tumour size estimation at CESM was significantly more accurate than LE alone, the latter tending to undersize lesions. In 75% of cases, CESM was deemed a useful or significant aid to diagnosis. CESM provides immediately available, clinically useful information in the symptomatic clinic in patients with suspicious palpable abnormalities. Radiologist sensitivity, specificity, and size accuracy for breast cancer detection and staging are all improved using CESM as the primary mammographic investigation. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Increased sensitivity of prolonged P-wave during exercise stress test in detection of angiographically documented coronary artery disease.

PubMed

Wsol, Agnieszka; Wydra, Wioletta; Chmielewski, Marek; Swiatowiec, Andrzej; Kuch, Marek

2017-01-01

A retrospective study was designed to investigate P-wave duration changes in exercise stress test (EST) for the prediction of angiographically documented substantial coronary artery disease (CAD). We analyzed 265 cases of patients, who underwent EST and subsequently coronary angiography. Analysis of P-wave duration was performed in leads II, V5 at rest, and in the recovery period. The sensitivity and specificity for the isolated ST-segment depression were only 31% and 76%, respectively. The combination of ST-depression with other exercise-induced clinical and electrocardio-graphic abnormalities (chest pain, ventricular arrhythmia, hypotension, left bundle branch block) was characterized by 41% sensitivity and 69% specificity. The combination of abnormal recovery P-wave duration (≥ 120 ms) with ST-depression and other exercise-induced abnormalities had 83% sensitivity but only 20% specificity. Combined analysis of increased delta P-wave duration, ST-depression and other exercise-induced abnormalities had 69% sensitivity and 42% specificity. Sensitivity and specificity of the increase in delta P-wave duration for left CAD was 69% and 47%, respectively, and for 3-vessel CAD 70% and 50%, respectively. The presence of arterial hypertension negatively influenced the prog-nostic value of P-wave changes in the stress test. The results of the study show that an addition of P-wave duration changes assessment to ST-depression analysis and other exercise-induced abnormalities increase sensitivity of EST, especially for left CAD and 3-vessel coronary disease. We have also provided evidence for the negative influence of the presence of arterial hypertension on the predictive value of P-wave changes in the stress test. (Cardiol J 2017; 24, 2: 159-166).

Non-contrast T1-mapping detects acute myocardial edema with high diagnostic accuracy: a comparison to T2-weighted cardiovascular magnetic resonance

PubMed Central

2012-01-01

Background T2w-CMR is used widely to assess myocardial edema. Quantitative T1-mapping is also sensitive to changes in free water content. We hypothesized that T1-mapping would have a higher diagnostic performance in detecting acute edema than dark-blood and bright-blood T2w-CMR. Methods We investigated 21 controls (55 ± 13 years) and 21 patients (61 ± 10 years) with Takotsubo cardiomyopathy or acute regional myocardial edema without infarction. CMR performed within 7 days included cine, T1-mapping using ShMOLLI, dark-blood T2-STIR, bright-blood ACUT2E and LGE imaging. We analyzed wall motion, myocardial T1 values and T2 signal intensity (SI) ratio relative to both skeletal muscle and remote myocardium. Results All patients had acute cardiac symptoms, increased Troponin I (0.15-36.80 ug/L) and acute wall motion abnormalities but no LGE. T1 was increased in patient segments with abnormal and normal wall motion compared to controls (1113 ± 94 ms, 1029 ± 59 ms and 944 ± 17 ms, respectively; p < 0.001). T2 SI ratio using STIR and ACUT2E was also increased in patient segments with abnormal and normal wall motion compared to controls (all p < 0.02). Receiver operator characteristics analysis showed that T1-mapping had a significantly larger area-under-the-curve (AUC = 0.94) compared to T2-weighted methods, whether the reference ROI was skeletal muscle or remote myocardium (AUC = 0.58-0.89; p < 0.03). A T1 value of greater than 990 ms most optimally differentiated segments affected by edema from normal segments at 1.5 T, with a sensitivity and specificity of 92 %. Conclusions Non-contrast T1-mapping using ShMOLLI is a novel method for objectively detecting myocardial edema with a high diagnostic performance. T1-mapping may serve as a complementary technique to T2-weighted imaging for assessing myocardial edema in ischemic and non-ischemic heart disease, such as quantifying area-at-risk and diagnosing myocarditis. PMID:22720998

Effects of diatrizoate and iopamidol on spermatogenesis.

PubMed

Yaghmai, V; Harapanhalli, R S; Patel, Y D; Baker, S R; Rao, D V

1993-12-01

The biological effects of iodinated contrast media were examined by using spermatogenesis in mouse testis as the experimental model. Spermhead survival and abnormality assays were used as the biological end points. Diatrizoate meglumine/diatrizoate sodium and iopamidol were administered intravenously at equal rates and concentrations. Testicular uptake and clearance of these contrast agents were examined by high-performance liquid chromatography techniques. Appropriate mannitol solutions were employed as osmolality controls. Intravenous administration of the contrast agent or its respective mannitol control resulted in approximately a 30% decrease in spermhead count. A dose-related experiment with mannitol demonstrated that the spermhead count decreased rapidly until 600 mOsm/kg was reached, beyond which this decrease was minimal. Clearance of both contrast media was complete in approximately 4 hours. No significant increase in the induction of spermhead abnormalities was observed. Osmotic substances, such as iodinated contrast agents, affect the process of spermatogenesis.

[Evaluation of echocardiography for determining left ventricular function].

PubMed

Wu, H; Zhu, W; Xu, J

1994-02-01

Left ventricular ejection fraction (LVEF) was calculated by echocardiography and gate blood pool (GBP) in 33 patients including those with coronary heart disease, acute and old myocardiac infarction, cardiomyopathy or mitral prolapse. Fourteen of the 33 had segmental wall motion abnormalities and 19 had non-segmental wall motion abnormalities. The results of comparing echocardiography and GBP showed that the former could substitute for other invasive and expensive examinations to determine LVEF (r = 0.804-0.964 in the 5 echocardiography methods used). Mod-Simpsons method of cross-sectioned echocardiography was the most accurate echocardiographic method (r = 0.964, sensitivity 90.9%) in all patients. The Teich method of M-mode echocardiography was useful in patients who had non-segmental wall motion abnormalities only (r = 0.957, sensitivity 94.7%) but not in patients who had segmental wall motion abnormalities (r = 0.703, sensitivity 42.9%).

Acute optic neuritis

PubMed Central

Galetta, Steven L.; Villoslada, Pablo; Levin, Netta; Shindler, Kenneth; Ishikawa, Hiroshi; Parr, Edward; Cadavid, Diego

2015-01-01

Idiopathic demyelinating optic neuritis (ON) most commonly presents as acute unilateral vision loss and eye pain and is frequently associated with multiple sclerosis. Although emphasis is often placed on the good recovery of high-contrast visual acuity, persistent deficits are frequently observed in other aspects of vision, including contrast sensitivity, visual field testing, color vision, motion perception, and vision-related quality of life. Persistent and profound structural and functional changes are often revealed by imaging and electrophysiologic techniques, including optical coherence tomography, visual-evoked potentials, and nonconventional MRI. These abnormalities can impair patients' abilities to perform daily activities (e.g., driving, working) so they have important implications for patients' quality of life. In this article, we review the sequelae from ON, including clinical, structural, and functional changes and their interrelationships. The unmet needs in each of these areas are considered and the progress made toward meeting those needs is examined. Finally, we provide an overview of past and present investigational approaches for disease modification in ON. PMID:26236761

[Diagnostic performance of surface electrocardiogram in early detection of chagasic cardiomyopathy].

PubMed

Bochard-Villanueva, Bruno; Estornell-Erill, Jordi; Fabregat-Andrés, Óscar; García-González, Pilar; Morell-Cabedo, Salvador; Ridocci-Soriano, Francisco

2015-03-15

Contrast-enhanced cardiac magnetic resonance imaging (CMR) allows early detection of myocardial involvement by Trypanosoma cruzi infection. The aim of our study was to assess the diagnostic performance of the surface electrocardiogram (ECG) in the early detection of Chagas' cardiomyopathy (CCM) compared with CMR. We included 43 asymptomatic patients (30 women, 42 ± 9.8 years), diagnosed of Chagas disease. The sample was divided into 2 groups according to the presence (n=17) or absence (n=26) of electrocardiographic abnormalities. All patients underwent CMR and late gadolinium enhancement (LGE) was used as a marker of early myocardial involvement. Six (14%) patients had a LGE significantly higher in the group who had electrocardiographic abnormalities (29 vs. 4%, P<.05). With CMR as the method of reference, the ECG had a sensitivity of 83% and a negative predictive value of 96% to detect CCM. ECG is a useful, inexpensive and globally available tool for the screening of CCM in asymptomatic patients but with proven myocardial involvement in CMR. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

Early Detection of Diabetic Retinopathy.

PubMed

Safi, Hamid; Safi, Sare; Hafezi-Moghadam, Ali; Ahmadieh, Hamid

2018-04-18

Diabetic retinopathy (DR) is a primary cause of visual impairment worldwide. Diabetes mellitus may be associated with ophthalmoscopically nonvisible neurovascular damage that progresses before the first clinical signs of DR appear. Reduction of the inner neuroretinal layer thickness on macular optical coherence tomography (OCT), reduced contrast sensitivity primarily at low spatial frequencies, abnormal results in color vision and microperimetry tests, and a prolonged implicit time recorded by multifocal electroretinography have been proposed for detection of early functional and nonvisible structural neuroretinal changes. Vascular abnormalities such as changes in the retinal vessels caliber, architectural indices, and blood flow have been investigated to evaluate the early stages of DR. The results of OCT angiography, retinal vessel oxygen saturation patterns, and elevated levels of circulating blood markers and cytokines have been suggested as early signs of DR. Light-based molecular imaging in rodents has been developed to demonstrate changes in protein expressions in the retinal microvessels as diagnostic biomarkers. Future clinical studies will examine the safety and efficacy of this approach in humans. We summarize all studies related to subclinical DR biomarkers. Copyright © 2018 Elsevier Inc. All rights reserved.

The impact of slice-reduced computed tomography on histogram-based densitometry assessment of lung fibrosis in patients with systemic sclerosis.

PubMed

Nguyen-Kim, Thi Dan Linh; Maurer, Britta; Suliman, Yossra A; Morsbach, Fabian; Distler, Oliver; Frauenfelder, Thomas

2018-04-01

To evaluate usability of slice-reduced sequential computed tomography (CT) compared to standard high-resolution CT (HRCT) in patients with systemic sclerosis (SSc) for qualitative and quantitative assessment of interstitial lung disease (ILD) with respect to (I) detection of lung parenchymal abnormalities, (II) qualitative and semiquantitative visual assessment, (III) quantification of ILD by histograms and (IV) accuracy for the 20%-cut off discrimination. From standard chest HRCT of 60 SSc patients sequential 9-slice-computed tomography (reduced HRCT) was retrospectively reconstructed. ILD was assessed by visual scoring and quantitative histogram parameters. Results from standard and reduced HRCT were compared using non-parametric tests and analysed by univariate linear regression analyses. With respect to the detection of parenchymal abnormalities, only the detection of intrapulmonary bronchiectasis was significantly lower in reduced HRCT compared to standard HRCT (P=0.039). No differences were found comparing visual scores for fibrosis severity and extension from standard and reduced HRCT (P=0.051-0.073). All scores correlated significantly (P<0.001) to histogram parameters derived from both, standard and reduced HRCT. Significant higher values of kurtosis and skewness for reduced HRCT were found (both P<0.001). In contrast to standard HRCT histogram parameters from reduced HRCT showed significant discrimination at cut-off 20% fibrosis (sensitivity 88% kurtosis and skewness; specificity 81% kurtosis and 86% skewness; cut-off kurtosis ≤26, cut-off skewness ≤4; both P<0.001). Reduced HRCT is a robust method to assess lung fibrosis in SSc with minimal radiation dose with no difference in scoring assessment of lung fibrosis severity and extension in comparison to standard HRCT. In contrast to standard HRCT histogram parameters derived from the approach of reduced HRCT could discriminate at a threshold of 20% lung fibrosis with high sensitivity and specificity. Hence it might be used to detect early disease progression of lung fibrosis in context of monitoring and treatment of SSc patients.

The Value of Ultrasound and Magnetic Resonance Imaging in Diagnostics and Prediction of Morbidity in Cases of Placenta Previa with Abnormal Placentation

PubMed Central

Algebally, Ahmed M.; Yousef, Reda Ramadan Hussein; Badr, Sanaa Sayed Hussein; Al Obeidly, Amal; Szmigielski, Wojciech; Al Ibrahim, Abdullah A.

2014-01-01

Summary Background The purpose of the study was to evaluate the role of ultrasound (US) and magnetic resonance imaging (MRI) in the diagnostics and management of abnormal placentation in women with placenta previa and to compare the morbidity associated with that to placenta previa alone. Material/Methods The study includes 100 pregnant women with placenta previa with and without abnormal placentation. The results of MRI and US in abnormal placentation were compared with post-operative data. The patients’ files were reviewed for assessment of operative and post-operative morbidity. The results of our statistical analysis were compared with data from the literature. Results US and MRI showed no significant difference in sensitivity and specificity in diagnosing abnormal placentation (97–100% and 94–100%, respectively). MRI was more sensitive than US for the detection of myometrial invasion and the type of abnormal placentation (73.5% and 47%, respectively). The difference between pre- and post-operative hemoglobin values and estimated blood loss were the most significant risk factors for abnormal placentation, added to risk factors known for placenta previa. Post-partum surgical complications and prolonged hospital stay were more common in the cases of placenta previa with abnormal placentation, however statistically insignificant. Conclusions US and MRI are accurate imaging modalities for diagnosing abnormal placentation. MRI was more sensitive for the detection of the degree of placental invasion. The patient’s morbidity increased in cases with abnormal placentation. There was no significant difference in post operative-complications and hospitalization time due to pre-operative planning when the diagnosis was established with US and MRI. PMID:25411586

Normal form from biological motion despite impaired ventral stream function.

PubMed

Gilaie-Dotan, S; Bentin, S; Harel, M; Rees, G; Saygin, A P

2011-04-01

We explored the extent to which biological motion perception depends on ventral stream integration by studying LG, an unusual case of developmental visual agnosia. LG has significant ventral stream processing deficits but no discernable structural cortical abnormality. LG's intermediate visual areas and object-sensitive regions exhibit abnormal activation during visual object perception, in contrast to area V5/MT+ which responds normally to visual motion (Gilaie-Dotan, Perry, Bonneh, Malach, & Bentin, 2009). Here, in three studies we used point light displays, which require visual integration, in adaptive threshold experiments to examine LG's ability to detect form from biological and non-biological motion cues. LG's ability to detect and discriminate form from biological motion was similar to healthy controls. In contrast, he was significantly deficient in processing form from non-biological motion. Thus, LG can rely on biological motion cues to perceive human forms, but is considerably impaired in extracting form from non-biological motion. Finally, we found that while LG viewed biological motion, activity in a network of brain regions associated with processing biological motion was functionally correlated with his V5/MT+ activity, indicating that normal inputs from V5/MT+ might suffice to activate his action perception system. These results indicate that processing of biologically moving form can dissociate from other form processing in the ventral pathway. Furthermore, the present results indicate that integrative ventral stream processing is necessary for uncompromised processing of non-biological form from motion. Copyright © 2011 Elsevier Ltd. All rights reserved.

Coronary vasomotor abnormalities in insulin-resistant individuals.

PubMed

Quiñones, Manuel J; Hernandez-Pampaloni, Miguel; Schelbert, Heinrich; Bulnes-Enriquez, Isabel; Jimenez, Xochitl; Hernandez, Gustavo; De La Rosa, Roxana; Chon, Yun; Yang, Huiying; Nicholas, Susanne B; Modilevsky, Tamara; Yu, Katherine; Van Herle, Katja; Castellani, Lawrence W; Elashoff, Robert; Hsueh, Willa A

2004-05-04

Insulin resistance is a metabolic spectrum that progresses from hyperinsulinemia to the metabolic syndrome, impaired glucose tolerance, and finally type 2 diabetes mellitus. It is unclear when vascular abnormalities begin in this spectrum of metabolic effects. To evaluate the association of insulin resistance with the presence and reversibility of coronary vasomotor abnormalities in young adults at low cardiovascular risk. Cross-sectional study followed by prospective, open-label treatment study. University hospital. 50 insulin-resistant and 22 insulin-sensitive, age-matched Mexican-American participants without glucose intolerance or traditional risk factors for or evidence of coronary artery disease. 3 months of thiazolidinedione therapy for 25 insulin-resistant patients. Glucose infusion rate in response to insulin infusion was used to define insulin resistance (glucose infusion rate < or = 4.00 mg/kg of body weight per minute [range, 0.90 to 3.96 mg/kg per minute]) and insulin sensitivity (glucose infusion rate > or = 7.50 mg/kg per minute [range, 7.52 to 13.92 mg/kg per minute]). Myocardial blood flow was measured by using positron emission tomography at rest, during cold pressor test (largely endothelium-dependent), and after dipyridamole administration (largely vascular smooth muscle-dependent). Myocardial blood flow responses to dipyridamole were similar in the insulin-sensitive and insulin-resistant groups. However, myocardial blood flow response to cold pressor test increased by 47.6% from resting values in insulin-sensitive patients and by 14.4% in insulin-resistant patients. During thiazolidinedione therapy in a subgroup of insulin-resistant patients, insulin sensitivity improved, fasting plasma insulin levels decreased, and myocardial blood flow responses to cold pressor test normalized. The study was not randomized, and it included only 1 ethnic group. Insulin-resistant patients who do not have hypercholesterolemia or hypertension and do not smoke manifest coronary vasomotor abnormalities. Insulin-sensitizing thiazolidinedione therapy normalized these abnormalities. These results suggest an association between insulin resistance and abnormal coronary vasomotor function, a relationship that requires confirmation in larger studies.

Contrast MR of the brain after high-perfusion cardiopulmonary bypass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simonson, T.M.; Yuh, W.T.C.; Hindman, B.J.

1994-01-01

To study the efficacy of contrast MR imaging in the evaluation of central nervous system complications in the cardiopulmonary bypass patient and attempt to explain their pathophysiology based on the MR appearance and the cardiopulmonary bypass protocol. Nineteen patients were prospectively studied with contrast MR examinations the day before and 3 to 7 days after cardiopulmonary bypass, to determine the nature, extent, and number of new postoperative MR abnormalities. Cardiopulmonary bypass parameters used in our institution included: membrane oxygenation, arterial filtration with a pore size of 25 [mu]m, and a relatively high perfusion rate to produce a cardiac index ofmore » 2.0 to 2.5 L min per m[sup 2]. The preoperative noncontrast MR examination showed age-related changes and/or signs of ischemia in 60% of patients on the day before surgery. However, there was no abnormal enhancement or new T2 abnormalities on any postoperative MR examination to suggest hypoperfusion or emboli. None of the 19 patients developed overt neurologic deficits postoperatively. Review of the cardiopulmonary bypass protocol used indicated significant variations in technique at different institutions. Contrast MR imaging demonstrated no new abnormalities in patients after cardiopulmonary bypass performed with strict in-line arterial filtration and relatively high perfusion. MR imaging is feasible in the early postoperative period after cardiopulmonary bypass and may offer a convenient method for evaluation of the neurologic impact of technical factors associated with cardiopulmonary bypass. 17 refs.« less

Conceptualizing neurodevelopmental disorders through a mechanistic understanding of fragile X syndrome and Williams syndrome.

PubMed

Fung, Lawrence K; Quintin, Eve-Marie; Haas, Brian W; Reiss, Allan L

2012-04-01

The overarching goal of this review is to compare and contrast the cognitive-behavioral features of fragile X syndrome (FraX) and Williams syndrome and to review the putative neural and molecular underpinnings of these features. Information is presented in a framework that provides guiding principles for conceptualizing gene-brain-behavior associations in neurodevelopmental disorders. Abnormalities, in particular cognitive-behavioral domains with similarities in underlying neurodevelopmental correlates, occur in both FraX and Williams syndrome including aberrant frontostriatal pathways leading to executive function deficits, and magnocellular/dorsal visual stream, superior parietal lobe, inferior parietal lobe, and postcentral gyrus abnormalities contributing to deficits in visuospatial function. Compelling cognitive-behavioral and neurodevelopmental contrasts also exist in these two disorders, for example, aberrant amygdala and fusiform cortex structure and function occurring in the context of contrasting social behavioral phenotypes, and temporal cortical and cerebellar abnormalities potentially underlying differences in language function. Abnormal dendritic development is a shared neurodevelopmental morphologic feature between FraX and Williams syndrome. Commonalities in molecular machinery and processes across FraX and Williams syndrome occur as well - microRNAs involved in translational regulation of major synaptic proteins; scaffolding proteins in excitatory synapses; and proteins involved in axonal development. Although the genetic variations leading to FraX and Williams syndrome are different, important similarities and contrasts in the phenotype, neurocircuitry, molecular machinery, and cellular processes in these two disorders allow for a unique approach to conceptualizing gene-brain-behavior links occurring in neurodevelopmental disorders.

Interplay between mast cells, enterochromaffin cells, and sensory signaling in the aging human bowel.

PubMed

Yu, Y; Daly, D M; Adam, I J; Kitsanta, P; Hill, C J; Wild, J; Shorthouse, A; Grundy, D; Jiang, W

2016-10-01

Advanced age is associated with a reduction in clinical visceral pain perception. However, the underlying mechanisms remain largely unknown. Previous studies have suggested that an abnormal interplay between mast cells, enterochromaffin (EC) cells, and afferent nerves contribute to nociception in gastrointestinal disorders. The aim of this study was to investigate how aging affects afferent sensitivity and neuro-immune association in the human bowel. Mechanical and chemical sensitivity of human bowel afferents were examined by ex vivo afferent nerve recordings. Age-related changes in the density of mast cells, EC cells, sensory nerve terminals, and mast cell-nerve micro-anatomical association were investigated by histological and immune staining. Human afferents could be broadly classified into subpopulations displaying mechanical and chemical sensitivity, adaptation, chemo-sensitization, and recruitment. Interestingly human bowel afferent nerve sensitivity was attenuated with age. The density of substance P-immunoreactive (SP-IR) nerve varicosities was also reduced with age. In contrast, the density of ileal and colonic mucosal mast cells was increased with age, as was ileal EC cell number. An increased proportion of mast cells was found in close apposition to SP-IR nerves. Afferent sensitivity in human bowel was reduced with advancing age. Augmentation of mast cells and EC cell numbers and the mast cell-nerve association suggest a compensatory mechanism for sensory neurodegeneration. © 2016 The Authors. Neurogastroenterology & Motility Published by John Wiley & Sons Ltd.

Arsenite-induced mitotic death involves stress response and is independent of tubulin polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, B. Frazier; McNeely, Samuel C.; Miller, Heather L.

2008-07-15

Arsenite, a known mitotic disruptor, causes cell cycle arrest and cell death at anaphase. The mechanism causing mitotic arrest is highly disputed. We compared arsenite to the spindle poisons nocodazole and paclitaxel. Immunofluorescence analysis of {alpha}-tubulin in interphase cells demonstrated that, while nocodazole and paclitaxel disrupt microtubule polymerization through destabilization and hyperpolymerization, respectively, microtubules in arsenite-treated cells remain comparable to untreated cells even at supra-therapeutic concentrations. Immunofluorescence analysis of {alpha}-tubulin in mitotic cells showed spindle formation in arsenite- and paclitaxel-treated cells but not in nocodazole-treated cells. Spindle formation in arsenite-treated cells appeared irregular and multi-polar. {gamma}-tubulin staining showed that cellsmore » treated with nocodazole and therapeutic concentrations of paclitaxel contained two centrosomes. In contrast, most arsenite-treated mitotic cells contained more than two centrosomes, similar to centrosome abnormalities induced by heat shock. Of the three drugs tested, only arsenite treatment increased expression of the inducible isoform of heat shock protein 70 (HSP70i). HSP70 and HSP90 proteins are intimately involved in centrosome regulation and mitotic spindle formation. HSP90 inhibitor 17-DMAG sensitized cells to arsenite treatment and increased arsenite-induced centrosome abnormalities. Combined treatment of 17-DMAG and arsenite resulted in a supra-additive effect on viability, mitotic arrest, and centrosome abnormalities. Thus, arsenite-induced abnormal centrosome amplification and subsequent mitotic arrest is independent of effects on tubulin polymerization and may be due to specific stresses that are protected against by HSP90 and HSP70.« less

Gain, noise, and contrast sensitivity of linear visual neurons

NASA Technical Reports Server (NTRS)

Watson, Andrew B.

1990-01-01

Contrast sensitivity is a measure of the ability of an observer to detect contrast signals of particular spatial and temporal frequencies. A formal definition of contrast sensitivity that can be applied to individual linear visual neurons is derived. A neuron is modeled by a contrast transfer function and its modulus, contrast gain, and by a noise power spectrum. The distributions of neural responses to signal and blank presentations are derived, and from these, a definition of contrast sensitivity is obtained. This formal definition may be used to relate the sensitivities of various populations of neurons, and to relate the sensitivities of neurons to that of the behaving animal.

Diagnostic grade wireless ECG monitoring.

PubMed

Garudadri, Harinath; Chi, Yuejie; Baker, Steve; Majumdar, Somdeb; Baheti, Pawan K; Ballard, Dan

2011-01-01

In remote monitoring of Electrocardiogram (ECG), it is very important to ensure that the diagnostic integrity of signals is not compromised by sensing artifacts and channel errors. It is also important for the sensors to be extremely power efficient to enable wearable form factors and long battery life. We present an application of Compressive Sensing (CS) as an error mitigation scheme at the application layer for wearable, wireless sensors in diagnostic grade remote monitoring of ECG. In our previous work, we described an approach to mitigate errors due to packet losses by projecting ECG data to a random space and recovering a faithful representation using sparse reconstruction methods. Our contributions in this work are twofold. First, we present an efficient hardware implementation of random projection at the sensor. Second, we validate the diagnostic integrity of the reconstructed ECG after packet loss mitigation. We validate our approach on MIT and AHA databases comprising more than 250,000 normal and abnormal beats using EC57 protocols adopted by the Food and Drug Administration (FDA). We show that sensitivity and positive predictivity of a state-of-the-art ECG arrhythmia classifier is essentially invariant under CS based packet loss mitigation for both normal and abnormal beats even at high packet loss rates. In contrast, the performance degrades significantly in the absence of any error mitigation scheme, particularly for abnormal beats such as Ventricular Ectopic Beats (VEB).

Magnetic resonance imaging of pulmonary infection in immunocompromised children: comparison with multidetector computed tomography.

PubMed

Ozcan, H Nursun; Gormez, Ayşegul; Ozsurekci, Yasemin; Karakaya, Jale; Oguz, Berna; Unal, Sule; Cetin, Mualla; Ceyhan, Mehmet; Haliloglu, Mithat

2017-02-01

Computed tomography (CT) is commonly used to detect pulmonary infection in immunocompromised children. To compare MRI and multidetector CT findings of pulmonary abnormalities in immunocompromised children. Seventeen neutropaenic children (6 girls; ages 2-18 years) were included. Non-contrast-enhanced CT was performed with a 64-detector CT scanner. Axial and coronal non-enhanced thoracic MRI was performed using a 1.5-T scanner within 24 h of the CT examination (true fast imaging with steady-state free precession, fat-saturated T2-weighted turbo spin echo with motion correction, T2-weighted half-Fourier single-shot turbo spin echo [HASTE], fat-saturated T1-weighted spoiled gradient echo). Pulmonary abnormalities (nodules, consolidations, ground glass opacities, atelectasis, pleural effusion and lymph nodes) were evaluated and compared among MRI sequences and between MRI and CT. The relationship between MRI sequences and nodule sizes was examined by chi- square test. Of 256 CT lesions, 207 (81%, 95% confidence interval [CI] 76-85%) were detected at MRI. Of 202 CT-detected nodules, 157 (78%, 95% CI 71-83%) were seen at motion-corrected MRI. Of the 1-5-mm nodules, 69% were detected by motion-corrected T2-weighted MRI and 38% by HASTE MRI. Sensitivity of MRI (both axial fat-saturated T2-weighted turbo spin echo with variable phase encoding directions (BLADE) images and HASTE sequences) to detect pulmonary abnormalities is promising.

[Which initial tests should be performed to evaluate meno-metrorrhagias? A comparison of hysterography, transvaginal sonohysterography and hysteroscopy].

PubMed

Descargues, G; Lemercier, E; David, C; Genevois, A; Lemoine, J P; Marpeau, L

2001-02-01

Evaluate the feasibility and the value of hysterography, sonohysterography and hysteroscopy for investigation of abnormal uterine bleeding. Method. Longitudinal blind study of thirty-eight patients consulting for abnormal uterine bleeding during pre- and post menopause. All patients underwent an hysterography and transvaginal sonohysterography, in random order, followed by an hysteroscopy with histological sample. The results were compared with the histo-pathological examination that was used for reference diagnosis. Statistical study of sensitivity, specificity and Positive and Negative Predictive Value (PPV-NPV) of each investigation; rate of agreement by the coefficient of Kappa. The hysterography offers a PPV of 83% and a NPV of 100%. The interpretation errors were associated with the simple mucous hypertrophy interpreted as "hyperplasy". The limits correspond to a contrast agent allergy. The sonohysterography had a VPP of 89% and a VPN of 100%. The false positive is due to the difficulties of distinguishing the clots from the polyps. The limits correspond to the difficulties of cervix catheterization (13%). As regards the hysteroscopy, the VPP was 81.5% and the VPN of 75%. The interpretation mistakes were associated with mucous hypertrophy and the hyperplasy. The most useful examination for abnormal uterine bleeding, in the first instance, is transvaginal sonography with saline instillation. A complement by Doppler study would probably make it possible to limit the false positives.

Pulsed electric field increases reproduction.

PubMed

Panagopoulos, Dimitris J

2016-01-01

Purpose To study the effect of pulsed electric field - applied in corona discharge photography - on Drosophila melanogaster reproduction, possible induction of DNA fragmentation, and morphological alterations in the gonads. Materials and methods Animals were exposed to different field intensities (100, 200, 300, and 400 kV/m) during the first 2-5 days of their adult lives, and the effect on reproductive capacity was assessed. DNA fragmentation during early- and mid-oogenesis was investigated by application of the TUNEL (Terminal deoxynucleotide transferase dUTP Nick End Labeling) assay. Sections of follicles after fixation and embedding in resins were observed for possible morphological/developmental abnormalities. Results The field increased reproduction by up to 30% by increasing reproductive capacity in both sexes. The effect increased with increasing field intensities. The rate of increase diminished at the strongest intensities. Slight induction of DNA fragmentation was observed exclusively in the nurse (predominantly) and follicle cells, and exclusively at the two most sensitive developmental stages, i.e., germarium and predominantly stage 7-8. Sections of follicles from exposed females at stages of early and mid-oogennesis other than germarium and stages 7-8 did not reveal abnormalities. Conclusions (1) The specific type of electric field may represent a mild stress factor, inducing DNA fragmentation and cell death in a small percentage of gametes, triggering the reaction of the animal's reproductive system to increase the rate of gametogenesis in order to compensate the loss of a small number of gametes. (2) The nurse cells are the most sensitive from all three types of egg chamber cells. (3) The mid-oogenesis checkpoint (stage 7-8) is more sensitive to this field than the early oogenesis one (germarium) in contrast to microwave exposure. (4) Possible therapeutic applications, or applications in increasing fertility, should be investigated.

(abstract) Effects of Radiation and Oxidative Stress on Development and Morphology of Intestinal Cells

NASA Technical Reports Server (NTRS)

Honda, Shuji; Nelson, Gregory; Schubert, Wayne

1993-01-01

Intestinal cells when subjected to oxidative stress or radiation exhibit abnormal nuclear divisions observed as: 1) supernumerary cell divisions in anterior intestinal cells or 2) incomplete nuclear division and the persistence of anaphase bridges between daughter nuclei. Two oxygen sensitive mutants, mev-1 and rad-8 were observed to exhibit spontaneous supernumerary nuclear divisions at low frequency. N2 can be induced to undergo these divisions by treatment with the superoxide dismutase (SOD) inhibitor diethyl dithicarbamate or with the free radical generator methyl viologen. By contrast, the free radical generator bleomycin produces anaphase bridges in N2 intestinal nuclei at high frequency. Intestinal anaphase bridges can be induced by ionizing radiation and their formation is dependent on dose and radiation type.

Customizing Perimetric Locations Based on En Face Images of Retinal Nerve Fiber Bundles With Glaucomatous Damage

PubMed Central

Alluwimi, Muhammed S.; Swanson, William H.; Malinovsky, Victor E.; King, Brett J.

2018-01-01

Purpose Prior studies suggested the use of customized perimetric locations in glaucoma; these studies were limited by imaging only the superficial depths of the retinal nerve fiber layer (RNFL) and by prolonged perimetric testing. We aimed to develop a rapid perimetric test guided by high-resolution images of RNFL bundles. Methods We recruited 10 patients with glaucoma, ages 56 to 80 years, median 68 years, and 10 controls, ages 55 to 77 years, median 68 years. The patients were selected based on discrepancies between locations of glaucomatous damage for perimetric and structural measures. Montaging was used to produce optical coherence tomography en face images of the RNFL covering much of the 24-2 grid locations. In experiment 1, we presented the Goldmann size III stimulus at preselected retinal locations of glaucomatous damage, using just two contrasts. In experiment 2, we developed an elongated sinusoidal stimulus, aligned within the defect, to measure contrast sensitivities; abnormalities were defined based on lower 95% reference limits derived from the controls. Results The percentage of predicted locations where size III was not seen at 28 dB ranged from 16% to 80%, with a median of 48%. Contrast sensitivity for the sinusoidal stimulus was below the 95% reference range for 37 of 44 stimuli aligned within the defects. Conclusions We developed methods for rapid perimetric testing guided by en face images of the RNFL bundles in patients with glaucoma. Results indicated ganglion cell damage under all of the visible RNFL defects. Translational Relevance Customized perimetric locations have potential to improve clinical assessment of glaucoma. PMID:29576929

Acute irritant threshold correlates with barrier function, skin hydration and contact hypersensitivity in atopic dermatitis and rosacea.

PubMed

Darlenski, Razvigor; Kazandjieva, Jana; Tsankov, Nikolai; Fluhr, Joachim W

2013-11-01

The aim of the study was to disclose interactions between epidermal barrier, skin irritation and sensitization in healthy and diseased skin. Transepidermal water loss (TEWL) and stratum corneum hydration (SCH) were assessed in adult patients with atopic dermatitis (AD), rosacea and healthy controls. A 4-h patch test with seven concentrations of sodium lauryl sulphate was performed to determine the irritant threshold (IT). Contact sensitization pattern was revealed by patch testing with European baseline series. Subjects with a lower IT had higher TEWL values and lower SCH. Subjects with positive allergic reactions had significantly lower IT. In AD, epidermal barrier deterioration was detected on both volar forearm and nasolabial fold, while in rosacea, impeded skin physiology parameters were observed on the facial skin only, suggesting that barrier impediment is restricted to the face in rosacea, in contrast with AD where the abnormal skin physiology is generalized. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species.

PubMed

Martino, Chiara; Bonaventura, Rosa; Byrne, Maria; Roccheri, Maria; Matranga, Valeria

2017-07-01

Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species. These different sensitivities highlight the importance of testing toxicity in several species for risk assessment. The strong negative effects of Gd on calcification in plutei, together with the plethora of marine species that have calcifying larvae, indicates that Gd pollution is urgent issue that needs to be addressed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clinical and imaging features in lung torsion and description of a novel imaging sign.

PubMed

Hammer, Mark M; Madan, Rachna

2018-04-01

We set out to identify the clinical and imaging features seen in lung torsion, a rare but emergent diagnosis leading to vascular compromise of a lobe or entire lung. We retrospectively identified 10 patients with torsion who underwent chest CT. We evaluated each case for the presence of bronchial obstruction and abnormal fissure orientation. In seven patients who underwent contrast-enhanced CTs, we assessed for the presence of the antler sign, a novel sign seen on axial images demonstrating abnormal curvature of the artery and branches originating on one side. Five patients had right middle lobe (RML) torsion after right upper lobectomy, and the remaining occurred following thoracentesis, aortic surgery, or spontaneously. Chest CTs demonstrated bronchial obstruction in eight cases and presence of abnormal fissure orientation in four patients. The antler sign was present in three patients with whole-lung torsion and one patient with lobar torsion; vascular swirling was seen on 3-D images in all seven patients with contrast-enhanced CTs. Lung parenchymal imaging findings in lung torsion may be non-specific. Identification of the antler sign on contrast-enhanced chest CT, in combination with other signs such as bronchial obstruction and abnormal fissure orientation, indicates rotation of the bronchovascular pedicle. The presence of this sign should prompt further evaluation with 3-dimensional reconstructions.

Prevalence of prenatal brain abnormalities in fetuses with congenital heart disease: a systematic review.

PubMed

Khalil, A; Bennet, S; Thilaganathan, B; Paladini, D; Griffiths, P; Carvalho, J S

2016-09-01

Studies have shown an association between congenital heart defects (CHDs) and postnatal brain abnormalities and neurodevelopmental delay. Recent evidence suggests that some of these brain abnormalities are present before birth. The primary aim of this study was to perform a systematic review to quantify the prevalence of prenatal brain abnormalities in fetuses with CHDs. MEDLINE, EMBASE and The Cochrane Library were searched electronically. Reference lists within each article were hand-searched for additional reports. The outcomes observed included structural brain abnormalities (on magnetic resonance imaging (MRI)) and changes in brain volume (on MRI, three-dimensional (3D) volumetric MRI, 3D ultrasound and phase-contrast MRI), brain metabolism or maturation (on magnetic resonance spectroscopy and phase-contrast MRI) and brain blood flow (on Doppler ultrasound, phase-contrast MRI and 3D power Doppler ultrasound) in fetuses with CHDs. Cohort and case-control studies were included and cases of chromosomal or genetic abnormalities, case reports and editorials were excluded. Proportion meta-analysis was used for analysis. Between-study heterogeneity was assessed using the I(2) test. The search yielded 1943 citations, and 20 studies (n = 1175 cases) were included in the review. Three studies reported data on structural brain abnormalities, while data on altered brain volume, metabolism and blood flow were reported in seven, three and 14 studies, respectively. The three studies (221 cases) reporting on structural brain abnormalities were suitable for inclusion in a meta-analysis. The prevalence of prenatal structural brain abnormalities in fetuses with CHD was 28% (95% CI, 18-40%), with a similar prevalence (25% (95% CI, 14-39%)) when tetralogy of Fallot was considered alone. These abnormalities included ventriculomegaly (most common), agenesis of the corpus callosum, ventricular bleeding, increased extra-axial space, vermian hypoplasia, white-matter abnormalities and delayed brain development. Fetuses with CHD were more likely than those without CHD to have reduced brain volume, delay in brain maturation and altered brain circulation, most commonly in the form of reduced middle cerebral artery pulsatility index and cerebroplacental ratio. These changes were usually evident in the third trimester, but some studies reported them from as early as the second trimester. In the absence of known major aneuploidy or genetic syndromes, fetuses with CHD are at increased risk of brain abnormalities, which are discernible prenatally. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

[Static and dynamic contrast sensitivity of myopic eyes before and after laser in situ keratomileusis].

PubMed

Liu, Xiao-wei; Pang, Guo-xiang; Liu, Xi-pu; Jiang, Ru-xin; Jin, Yu-mei; Sun, Yu-min; Wang, Zhong-hai

2003-10-01

To evaluate the static and dynamic contrast sensitivity changes in myopic patients before and after laser in situ keratomileusis (LASIK). Seventy-three eyes in 37 patients with myopia (with or without astigmatism) who received LASIK were tested for static and dynamic contrast sensitivities using the METRO VISION MON ELEC I system at 0.7, 1.4, 2.7, 5.5, 11, and 22 cpd and cps prior to LASIK, and at one-, three-, and six-month intervals after LASIK. All eyes gained naked visual acuity of more than 0.5 after LASIK. The contrast sensitivity was depressed at all frequencies 1 month after LASIK, as compared to one week prior to LASIK. The depression at 2.7, 5.5, 11 (P < 0.01) and 22 cpd (P < 0.05) was statistically significant for static contrast sensitivity, and also at 5.5 (P < 0.01) and 11 cps (P < 0.05) for dynamic contrast sensitivity. Myopic eyes between 6.25 D and 14.0 D, and astigmatic eyes 2 DC and more, suffered more static and dynamic contrast sensitivity depression than the myopic eyes between 1.25 D and 6.00 D and astigmatic eyes less than 2 DC. Contrast sensitivities were improved and exceeded preoperative levels 3 months after LASIK, and improved even more 6 months after LASIK. All sequences were statistically significant for static contrast sensitivity (P < 0.01), while only 2.7, 5.5, and 11 cps were statistically significant for dynamic contrast sensitivity (P < 0.01). The astigmatic eyes 2 DC and more showed less improvement, even below the preoperative level at 1.4 cps of dynamic contrast sensitivity. While temporary depression of contrast sensitivity for myopic eyes after LASIK was seen, contrast sensitivity soon returned to exceed preoperative levels at 3 months after LASIK, while improving even more 6 months after LASIK.

Adenotonsillar hypertrophy as a risk factor of dentofacial abnormality in Korean children.

PubMed

Kim, Dong-Kyu; Rhee, Chae Seo; Yun, Pil-Young; Kim, Jeong-Whun

2015-11-01

No studies for the role of adenotonsillar hypertrophy in development of dentofacial abnormalities have been performed in Asian pediatric population. Thus, we aimed to investigate the relationship between adenotonsillar hypertrophy and dentofacial abnormalities in Korean children. The present study included consecutive children who visited a pediatric clinic for sleep-disordered breathing due to habitual mouth breathing, snoring or sleep apnea. Their palatine tonsils and adenoids were graded by oropharyngeal endoscopy and lateral cephalometry. Anterior open bite, posterior crossbite, and Angle's class malocclusions were evaluated for dentofacial abnormality. The receiver-operating characteristic curve analysis was used to identify age cutoffs to predict dentofacial abnormality. A total of 1,083 children were included. The presence of adenotonsillar hypertrophy was significantly correlated with the prevalence of dentofacial abnormality [adjusted odds ratio = 4.587, 95% CI (2.747-7.658)] after adjusting age, sex, body mass index, allergy, and Korean version of obstructive sleep apnea-18 score. The cutoff age associated with dentofacial abnormality was 5.5 years (sensitivity = 75.5%, specificity = 67%) in the children with adenotonsillar hypertrophy and 6.5 years (sensitivity = 70.6%, specificity = 57%) in those without adenotonsillar hypertrophy. In conclusion, adenotonsillar hypertrophy may be a risk factor for dentofacial abnormalities in Korean children and early surgical intervention could be considered with regards to dentofacial abnormality.

Evaluating psychological markers for human nicotine dependence: tobacco choice, extinction, and Pavlovian-to-instrumental transfer.

PubMed

Hogarth, Lee; Chase, Henry W

2012-06-01

Individual differences in drug dependence may be mediated by several abnormalities in associative learning, including perseveration of drug-seeking following contingency change, greater control over drug-seeking by Pavlovian stimuli, or greater sensitivity to drug reinforcement establishing higher rates of drug-seeking. To evaluate these three candidate markers for nicotine dependence, Experiment 1 contrasted daily (N = 22) and nondaily smoker groups (N = 22) on a novel instrumental learning task, where one S+ was first trained as a predictor of tobacco reward before being extinguished. Experiment 2 compared daily (N = 18) and nondaily smoker groups (N = 18) on a concurrent-choice task for tobacco and chocolate reward before an extinction test in which the tobacco response was extinguished, followed by a Pavlovian-to-instrumental transfer test, wherein the impact of tobacco and chocolate cues on concurrent choice was measured (gender was balanced within each smoker group). The results showed no group difference in sensitivity to extinction of either the stimulus-drug or response-drug contingency in Experiments 1 and 2, respectively, nor did groups show a difference in Pavlovian-to-instrumental transfer of control over tobacco choice. By contrast, nicotine-dependence status was marked by a higher frequency of tobacco choice in the concurrent-choice procedure, and this choice preference was associated with subjective craving (gender did not affect any behavioral measure). These results favor the view that nicotine dependence in this sample is not determined by individual predilection for perseveration or stimulus-control over drug-seeking, but by greater sensitivity to reinforcement of instrumental drug choice. Value-based decision theories of dependence are discussed.

Conceptualizing neurodevelopmental disorders through a mechanistic understanding of fragile X syndrome and Williams syndrome

PubMed Central

Fung, Lawrence K.; Quintin, Eve-Marie; Haas, Brian W.

2013-01-01

Purpose of review The overarching goal of this review is to compare and contrast the cognitive-behavioral features of fragile X syndrome (FraX) and Williams syndrome and to review the putative neural and molecular underpinnings of these features. Information is presented in a framework that provides guiding principles for conceptualizing gene-brain-behavior associations in neurodevelopmental disorders. Recent findings Abnormalities, in particular cognitive-behavioral domains with similarities in underlying neurodevelopmental correlates, occur in both FraX and Williams syndrome including aberrant frontostriatal pathways leading to executive function deficits, and magnocellular/dorsal visual stream, superior parietal lobe, inferior parietal lobe, and postcentral gyrus abnormalities contributing to deficits in visuospatial function. Compelling cognitive–behavioral and neurodevelopmental contrasts also exist in these two disorders, for example, aberrant amygdala and fusiform cortex structure and function occurring in the context of contrasting social behavioral phenotypes, and temporal cortical and cerebellar abnormalities potentially underlying differences in language function. Abnormal dendritic development is a shared neurodevelopmental morphologic feature between FraX and Williams syndrome. Commonalities in molecular machinery and processes across FraX and Williams syndrome occur as well – microRNAs involved in translational regulation of major synaptic proteins; scaffolding proteins in excitatory synapses; and proteins involved in axonal development. Summary Although the genetic variations leading to FraX and Williams syndrome are different, important similarities and contrasts in the phenotype, neurocircuitry, molecular machinery, and cellular processes in these two disorders allow for a unique approach to conceptualizing gene–brain–behavior links occurring in neurodevelopmental disorders. PMID:22395002

Imaging of dental material by polarization-sensitive optical coherence tomography

NASA Astrophysics Data System (ADS)

Dichtl, Sabine; Baumgartner, Angela; Hitzenberger, Christoph K.; Moritz, Andreas; Wernisch, Johann; Robl, Barbara; Sattmann, Harald; Leitgeb, Rainer; Sperr, Wolfgang; Fercher, Adolf F.

1999-05-01

Partial coherence interferometry (PCI) and optical coherence tomography (OCT) are noninvasive and noncontact techniques for high precision biometry and for obtaining cross- sectional images of biologic structures. OCT was initially introduced to depict the transparent tissue of the eye. It is based on interferometry employing the partial coherence properties of a light source with high spatial coherence ut short coherence length to image structures with a resolution of the order of a few microns. Recently this technique has been modified for cross section al imaging of dental and periodontal tissues. In vitro and in vivo OCT images have been recorded, which distinguish enamel, cemento and dentin structures and provide detailed structural information on clinical abnormalities. In contrast to convention OCT, where the magnitude of backscattered light as a function of depth is imaged, polarization sensitive OCT uses backscattered light to image the magnitude of the birefringence in the sample as a function of depth. First polarization sensitive OCT recordings show, that changes in the mineralization status of enamel or dentin caused by caries or non-caries lesions can result in changes of the polarization state of the light backscattered by dental material. Therefore polarization sensitive OCT might provide a new diagnostic imaging modality in clinical and research dentistry.

The Effect of Ocular Surface Regularity on Contrast Sensitivity and Straylight in Dry Eye.

PubMed

Koh, Shizuka; Maeda, Naoyuki; Ikeda, Chikako; Asonuma, Sanae; Ogawa, Mai; Hiraoka, Takahiro; Oshika, Tetsuro; Nishida, Kohji

2017-05-01

To investigate the association between visual function and ocular surface regularity in dry eye. We enrolled 52 eyes of 52 dry eye patients (34 dry eyes with superficial punctate keratopathy [SPK] in the central corneal region [central SPK] and 18 dry eyes without central SPK) and 20 eyes of 20 normal control subjects. All eyes had a best-corrected distance visual acuity better than 20/20. We measured two indices of contrast sensitivity function under photopic conditions: contrast sensitivity and letter contrast sensitivity. The area under the log contrast sensitivity function (AULCSF) was calculated from the obtained contrast sensitivity data. Straylight was quantified using a straylight meter. Dry eyes with central SPK had significantly decreased contrast sensitivity function, including AULCSF and letter contrast sensitivity than those without central SPK and normal eyes (P < 0.05 for each). While the straylight values in both dry eye groups did not differ, straylight values were greater than those in normal eyes (P < 0.05 for both). In dry eye, the AULCSF and letter contrast sensitivity negatively correlated with the central SPK score (R = -0.485, P < 0.001, and R = -0.541, P < 0.001, respectively). In dry eye, reduced contrast sensitivity in part results from central SPK overlying the optical zone and the increased straylight results from tear film instability rather than central SPK.

Using Correlative Properties of Neighboring Pixels to Enhance Contrast-to-Noise Ratio of Abnormal Hippocampus in Patients With Intractable Epilepsy and Mesial Temporal Sclerosis.

PubMed

Parsons, Matthew S; Sharma, Aseem; Hildebolt, Charles

2018-06-12

To test whether an image-processing algorithm can aid in visualization of mesial temporal sclerosis on magnetic resonance imaging by selectively increasing contrast-to-noise ratio (CNR) between abnormal hippocampus and normal brain. In this Institutional Review Board-approved and Health Insurance Portability and Accountability Act-compliant study, baseline coronal fluid-attenuated inversion recovery images of 18 adults (10 females, eight males; mean age 41.2 years) with proven mesial temporal sclerosis were processed using a custom algorithm to produce corresponding enhanced images. Average (Hmean) and maximum (Hmax) CNR for abnormal hippocampus were calculated relative to normal ipsilateral white matter. CNR values for normal gray matter (GM) were similarly calculated using ipsilateral cingulate gyrus as the internal control. To evaluate effect of image processing on visual conspicuity of hippocampal signal alteration, a neuroradiologist masked to the side of hippocampal abnormality rated signal intensity (SI) of hippocampi on baseline and enhanced images using a five-point scale (definitely abnormal to definitely normal). Differences in Hmean, Hmax, GM, and SI ratings for abnormal hippocampi on baseline and enhanced images were assessed for statistical significance. Both Hmean and Hmax were significantly higher in enhanced images as compared to baseline images (p < 0.0001 for both). There was no significant difference in the GM between baseline and enhanced images (p = 0.9375). SI ratings showed a more confident identification of abnormality on enhanced images (p = 0.0001). Image-processing resulted in increased CNR of abnormal hippocampus without affecting the CNR of normal gray matter. This selective increase in conspicuity of abnormal hippocampus was associated with more confident identification of hippocampal signal alteration. Copyright © 2018 Academic Radiology. Published by Elsevier Inc. All rights reserved.

Written Assignments for Abnormal Psychology at Howard Community College, Fall 1988.

ERIC Educational Resources Information Center

Bell, James

Designed for students enrolled in an Abnormal Psychology course at Howard Community College (Maryland), this booklet explains the requirements for the course's writing assignments, which are designed to teach the skills of comparison and contrast, analysis, critical thinking, and synthesis. Following an overview of class assignments and…

Recognizing patterns of visual field loss using unsupervised machine learning

NASA Astrophysics Data System (ADS)

Yousefi, Siamak; Goldbaum, Michael H.; Zangwill, Linda M.; Medeiros, Felipe A.; Bowd, Christopher

2014-03-01

Glaucoma is a potentially blinding optic neuropathy that results in a decrease in visual sensitivity. Visual field abnormalities (decreased visual sensitivity on psychophysical tests) are the primary means of glaucoma diagnosis. One form of visual field testing is Frequency Doubling Technology (FDT) that tests sensitivity at 52 points within the visual field. Like other psychophysical tests used in clinical practice, FDT results yield specific patterns of defect indicative of the disease. We used Gaussian Mixture Model with Expectation Maximization (GEM), (EM is used to estimate the model parameters) to automatically separate FDT data into clusters of normal and abnormal eyes. Principal component analysis (PCA) was used to decompose each cluster into different axes (patterns). FDT measurements were obtained from 1,190 eyes with normal FDT results and 786 eyes with abnormal (i.e., glaucomatous) FDT results, recruited from a university-based, longitudinal, multi-center, clinical study on glaucoma. The GEM input was the 52-point FDT threshold sensitivities for all eyes. The optimal GEM model separated the FDT fields into 3 clusters. Cluster 1 contained 94% normal fields (94% specificity) and clusters 2 and 3 combined, contained 77% abnormal fields (77% sensitivity). For clusters 1, 2 and 3 the optimal number of PCA-identified axes were 2, 2 and 5, respectively. GEM with PCA successfully separated FDT fields from healthy and glaucoma eyes and identified familiar glaucomatous patterns of loss.

Abnormal IgG4 antibody response to aeroallergens in allergic patients.

PubMed

Jeannin, P; Delneste, Y; Tillie-Leblond, I; Wallaert, B; carlier, A; Pestel, J; Tonnel, A B

1994-01-01

Various studies have suggested the involvement of immunoglobulin G4 (IgG4) antibodies (Ab) in the physiopathology of allergic disorders. Recently, an abnormal IgG4 Ab production in response to immunization has been reported in some atopic patients. Thus, in order to evidence in allergic patients, a potential abnormal IgG4 Ab response to aeroallergens following natural exposure, we compared, in 34 patients sensitive to Dermatophagoides pteronyssinus and in 16 healthy subjects, the IgG4 Ab response to D. pteronyssinus, grass pollen and cat dander, using a solid-phase radioimmunoassay. Since some patients were also sensitive to grass pollen and/or to cat dander, we analyzed, in all patients, the IgG4 Ab responses both towards the allergen(s) they were sensitive to (sensitizing allergen) or not (unrelated allergen). The results showed that 90% of the patients produced levels of antisensitizing allergen(s) IgG4 Ab significantly higher than the controls; this IgG4 Ab response was correlated with the corresponding specific IgE Ab level. In addition, among these patients, around 40% presented high levels of IgG4 Ab to the unrelated allergen(s). Thus, in allergic patients, while specific IgE Ab define the nature of the sensitizing allergen, the presence of IgG4 Ab directed against various allergens seems in relation with an abnormal isotype regulation associated with atopic disorders.

Evaluation of the Lactate-to-N-Acetyl-aspartate Ratio Defined With Magnetic Resonance Spectroscopic Imaging Before Radiation Therapy as a New Predictive Marker of the Site of Relapse in Patients With Glioblastoma Multiforme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deviers, Alexandra; UMR; INP

Purpose: Because lactate accumulation is considered a surrogate for hypoxia and tumor radiation resistance, we studied the spatial distribution of the lactate-to-N-acetyl-aspartate ratio (LNR) before radiation therapy (RT) with 3D proton magnetic resonance spectroscopic imaging (3D-{sup 1}H-MRSI) and assessed its impact on local tumor control in glioblastoma (GBM). Methods and Materials: Fourteen patients with newly diagnosed GBM included in a phase 2 chemoradiation therapy trial constituted our database. Magnetic resonance imaging (MRI) and MRSI data before RT were evaluated and correlated to MRI data at relapse. The optimal threshold for tumor-associated LNR was determined with receiver-operating-characteristic (ROC) curve analysis ofmore » the pre-RT LNR values and MRI characteristics of the tumor. This threshold was used to segment pre-RT normalized LNR maps. Two spatial analyses were performed: (1) a pre-RT volumetric comparison of abnormal LNR areas with regions of MRI-defined lesions and a choline (Cho)-to- N-acetyl-aspartate (NAA) ratio ≥2 (CNR2); and (2) a voxel-by-voxel spatial analysis of 4,186,185 voxels with the intention of evaluating whether pre-RT abnormal LNR areas were predictive of the site of local recurrence. Results: A LNR of ≥0.4 (LNR-0.4) discriminated between tumor-associated and normal LNR values with 88.8% sensitivity and 97.6% specificity. LNR-0.4 voxels were spatially different from those of MRI-defined lesions, representing 44% of contrast enhancement, 64% of central necrosis, and 26% of fluid-attenuated inversion recovery (FLAIR) abnormality volumes before RT. They extended beyond the overlap with CNR2 for most patients (median: 20 cm{sup 3}; range: 6-49 cm{sup 3}). LNR-0.4 voxels were significantly predictive of local recurrence, regarded as contrast enhancement at relapse: 71% of voxels with a LNR-0.4 before RT were contrast enhanced at relapse versus 10% of voxels with a normal LNR (P<.01). Conclusions: Pre-RT LNR-0.4 in GBM indicates tumor areas that are likely to relapse. Further investigations are needed to confirm lactate imaging as a tool to define additional biological target volumes for dose painting.« less

Medial tibial pain: a dynamic contrast-enhanced MRI study.

PubMed

Mattila, K T; Komu, M E; Dahlström, S; Koskinen, S K; Heikkilä, J

1999-09-01

The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrast enhanced imaging to show periosteal edema and abnormal contrast enhancement within a compartment.

Evaluation of patellar chondromalacia with MR: comparison between T2-weighted FSE SPIR and GE MTC.

PubMed

Macarini, Luca; Perrone, Alessandra; Murrone, Mario; Marini, Stefania; Stefanelli, Michele

2004-09-01

To compare two different MR sequences to tissue signal suppression in the study of patellar cartilage abnormalities. We examined 26 patients with magnetic resonance (MR) imaging: sequences included spectral presaturation with inversion recovery (SPIR), with fat suppression and T2-weighted images, magnetization transfer contrast (MTC) sequences, T1-weighted and T2-weighted spin-echo sequences. All patients underwent conventional knee arthroscopy and in all patients a hyaline cartilage lesion was assessed in three articular zones: the patellar medial facet, the lateral facet and the patellar crista. Was assessed 78 articular facets. The lesions were classified using a standard arthroscopic grading system adapted to MR imaging: normal cartilage that corresponds to the grade 0 according to the Noyes grading system, low grade lesions that correspond to the grade I e IIa and high grade lesions that correspond to grades IIb and III. The arthroscopic results were compared with MR images. We assessed the MR diagnostic accuracy, sensitivity, specificity and MR positive predictive value and negative predictive value of the two sequences taking into consideration total lesions, and high-grade and low grade lesions separately. Twenty-four low grade lesions (16 grade I e 8 grade IIa) and 18 high grade lesions (10 grade IIb e 8 grade III) were diagnosed by arthroscopy. Regarding low grade and high-grade lesions together, the accuracy was 77% for MTC sequences and 90% for SPIR sequences. In identifying low-grade lesions, the sensitivity was 88% for SPIR sequence and 42% for MTC sequences. Specificity for the detection of all lesions was 89% for the SPIR sequences and 94% for the MTC sequences. The SPIR sequence visualised water content abnormalities in degenerating cartilage, which are representative of low-grade lesions. The sensitivity of the sequence enabled us to obtain improved contrast for detecting cartilage surface irregularities. The MTC sequences allowed us to grade high-grade lesions susceptible to surgery and small cartilage defects in the presence of joint fluid. The MTC sequences were insufficient in the diagnosis of early stages of chondromalacia because the suppression of the signal of bonded water reduced the contrast among areas of articular cartilage with different water content. For this reason cartilage oedema and early superficial fibrillation were not identified. In our experience the SPIR sequence proved superior to the MTC sequence in the identification of low grade lesions of the patellar cartilage. The overall value of such sequences in the study of articular pathology also needs to be assessed in the others sites where the articular cartilage is thinner and surfaces more curvilinear.

Surgical treatment of temporal lobe epilepsy: clinical, radiological, and histopathological findings in 178 patients.

PubMed Central

Zentner, J; Hufnagel, A; Wolf, H K; Ostertun, B; Behrens, E; Campos, M G; Solymosi, L; Elger, C E; Wiestler, O D; Schramm, J

1995-01-01

The surgical treatment of pharmacoresistant temporal lobe epilepsy is increasing rapidly. The correlation of preoperative MRI, histopathological findings, and postoperative seizure control is reported for 178 patients with chronic medically intractable temporal lobe epilepsy who were operated on between November 1987 and January 1993. Histopathologically there were distinct structural abnormalities in 97.2% of the surgical specimens. Signal abnormalities on MRI were present in 98.7% of patients with neoplastic lesions (n = 79), 76.6% of patients with non-neoplastic focal lesions (n = 55), and 69.2% of patients with Ammon's horn sclerosis (n = 39). Overall, structural abnormalities were detected by MRI in 82.7% of all patients. The mean postoperative follow up period was three years. Some 92% of the patients benefited from surgery: 103 patients (61.7%) were seizure free, 26 (15.5%) had no more than two seizures a year, and 24 (14.4%) showed a reduction of seizure frequency of at least 75%. Fourteen patients (8.4%) had a < 75% reduction of seizure frequency. The percentage of patients who were completely free of seizures after operation was 68.5% for patients with neoplastic lesions, 66.7% for Ammon's horn sclerosis, and 54.0% for patients with non-neoplastic focal lesions. By contrast, none of the patients in whom histopathological findings were normal became seizure free postoperatively. The data show that the presence of focal lesions or Ammon's horn sclerosis as determined by histopathological examination is associated with improved postoperative seizure control compared with patients without specific pathological findings. Brain MRI was very sensitive in detecting neoplasms; however, its sensitivity and specificity were limited with respect to non-neoplastic focal lesions and Ammon's horn sclerosis. Improvement of imaging techniques may provide a more precise definition of structural lesions in these cases and facilitate limited surgical resections of the epileptogenic area rather than standardised anatomical resections. Images PMID:7608662

Handwriting training in Parkinson’s disease: A trade-off between size, speed and fluency

PubMed Central

Broeder, Sanne; Pereira, Marcelo P.; Swinnen, Stephan P.; Vandenberghe, Wim; Nieuwboer, Alice; Heremans, Elke

2017-01-01

Background In previous work, we found that intensive amplitude training successfully improved micrographia in Parkinson’s disease (PD). Handwriting abnormalities in PD also express themselves in stroke duration and writing fluency. It is currently unknown whether training changes these dysgraphic features. Objective To determine the differential effects of amplitude training on various hallmarks of handwriting abnormalities in PD. Methods We randomized 38 right-handed subjects in early to mid-stage of PD into an experimental group (n = 18), receiving training focused at improving writing size during 30 minutes/day, five days/week for six weeks, and a placebo group (n = 20), receiving stretch and relaxation exercises at equal intensity. Writing skills were assessed using a touch-sensitive tablet pre- and post-training, and after a six-week retention period. Tests encompassed a transfer task, evaluating trained and untrained sequences, and an automatization task, comparing single- and dual-task handwriting. Outcome parameters were stroke duration (s), writing velocity (cm/s) and normalized jerk (i.e. fluency). Results In contrast to the reported positive effects of training on writing size, the current results showed increases in stroke duration and normalized jerk after amplitude training, which were absent in the placebo group. These increases remained after the six-week retention period. In contrast, velocity remained unchanged throughout the study. Conclusion While intensive amplitude training is beneficial to improve writing size in PD, it comes at a cost as fluency and stroke duration deteriorated after training. The findings imply that PD patients can redistribute movement priorities after training within a compromised motor system. PMID:29272301

Handwriting training in Parkinson's disease: A trade-off between size, speed and fluency.

PubMed

Nackaerts, Evelien; Broeder, Sanne; Pereira, Marcelo P; Swinnen, Stephan P; Vandenberghe, Wim; Nieuwboer, Alice; Heremans, Elke

2017-01-01

In previous work, we found that intensive amplitude training successfully improved micrographia in Parkinson's disease (PD). Handwriting abnormalities in PD also express themselves in stroke duration and writing fluency. It is currently unknown whether training changes these dysgraphic features. To determine the differential effects of amplitude training on various hallmarks of handwriting abnormalities in PD. We randomized 38 right-handed subjects in early to mid-stage of PD into an experimental group (n = 18), receiving training focused at improving writing size during 30 minutes/day, five days/week for six weeks, and a placebo group (n = 20), receiving stretch and relaxation exercises at equal intensity. Writing skills were assessed using a touch-sensitive tablet pre- and post-training, and after a six-week retention period. Tests encompassed a transfer task, evaluating trained and untrained sequences, and an automatization task, comparing single- and dual-task handwriting. Outcome parameters were stroke duration (s), writing velocity (cm/s) and normalized jerk (i.e. fluency). In contrast to the reported positive effects of training on writing size, the current results showed increases in stroke duration and normalized jerk after amplitude training, which were absent in the placebo group. These increases remained after the six-week retention period. In contrast, velocity remained unchanged throughout the study. While intensive amplitude training is beneficial to improve writing size in PD, it comes at a cost as fluency and stroke duration deteriorated after training. The findings imply that PD patients can redistribute movement priorities after training within a compromised motor system.

Clinical Utility and Lifespan Profiling of Neurological Soft Signs in Schizophrenia Spectrum Disorders

PubMed Central

Chan, Raymond C. K.; Xie, Weizhen; Geng, Fu-lei; Wang, Ya; Lui, Simon S. Y.; Wang, Chuan-yue; Yu, Xin; Cheung, Eric F. C.; Rosenthal, Robert

2016-01-01

Neurological soft signs (NSSs) bear the promise for early detection of schizophrenia spectrum disorders. Nonetheless, the sensitivity and specificity of NSSs in the psychosis continuum remains a topic of controversy. It is also unknown how NSSs reveal neurodevelopmental abnormality in schizophrenia. We investigated the effect sizes of NSSs in differentiating individuals with schizophrenia spectrum disorders from individuals with other psychiatric conditions and from covariate-matched healthy subjects. We also investigated the partitioned age-related variations of NSSs in both schizophrenia and healthy individuals. NSSs were assessed by the abridged version of the Cambridge Neurological Inventory (CNI) in 3105 participants, consisting of healthy individuals (n =1577), unaffected first-degree relatives of schizophrenia patients (n = 155), individuals with schizotypal personality disorder (n = 256), schizophrenia patients (n = 738), and other psychiatric patients (n = 379). Exact matching and propensity score matching procedures were performed to control for covariates. Multiple regression was used to partition age-related variations. Individuals along the schizophrenia continuum showed elevated levels of NSSs, with moderate effect sizes, in contrast to other psychiatric patients who had minimal NSSs, as well as matched healthy controls. Furthermore, the age-and-NSS relationship in schizophrenia patients was represented by a flat but overall elevated pattern, in contrast to a U-shaped pattern in healthy individuals. In sum, NSSs capture a moderate portion of psychosis proneness with reasonable specificity. Lifespan profiling reveals an abnormal developmental trajectory of NSSs in schizophrenia patients, which supports the endophenotype hypothesis of NSSs by associating it with the neurodevelopmental model of schizophrenia. PMID:26712863

Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

PubMed

Berko, Netanel S; Hay, Arielle; Sterba, Yonit; Wahezi, Dawn; Levin, Terry L

2015-09-01

Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31%, respectively, with a sensitivity of 40% and specificity of 67%. Compression-strain US elastography does not accurately detect active myositis in children with juvenile idiopathic inflammatory myopathy and cannot replace MRI as the imaging standard for detecting myositis in these children. The association between abnormal US elastography and increased muscle echogenicity suggests that elastography is capable of detecting muscle derangement in patients with myositis; however further studies are required to determine the clinical significance of these findings.

Replacement of the Faces subtest by Visual Reproductions within Wechsler Memory Scale-Third Edition (WMS-III) visual memory indexes: implications for discrepancy analysis.

PubMed

Hawkins, Keith A; Tulsky, David S

2004-06-01

Within discrepancy analysis differences between scores are examined for abnormality. Although larger differences are generally associated with rising impairment probabilities, the relationship between discrepancy size and abnormality varies across score pairs in relation to the correlation between the contrasted scores in normal subjects. Examinee ability level also affects the size of discrepancies observed normally. Wechsler Memory Scale-Third Edition (WMS-III) visual index scores correlate only modestly with other Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) and WMS-III index scores; consequently, differences between these scores and others have to be very large before they become unusual, especially for subjects of higher intelligence. The substitution of the Faces subtest by Visual Reproductions within visual memory indexes formed by the combination of WMS-III visual subtests (creating immediate recall, delayed recall, and combined immediate and delayed index scores) results in higher correlation coefficients, and a decline in the discrepancy size required to surpass base rate thresholds for probable impairment. This gain appears not to occur at the cost of a diminished sensitivity to diverse pathologies. New WMS-III discrepancy base rate data are supplied to complement those currently available to clinicians.

Optical defocus: differential effects on size and contrast letter recognition thresholds.

PubMed

Rabin, J

1994-02-01

To determine if optical defocus produces a greater reduction in visual acuity or small-letter contrast sensitivity. Letter charts were used to measure visual acuity and small-letter contrast sensitivity (20/25 Snellen equivalent) as a function of optical defocus. Letter size (acuity) and contrast (contrast sensitivity) were varied in equal logarithmic steps to make the task the same for the two types of measurement. Both visual acuity and contrast sensitivity declined with optical defocus, but the effect was far greater in the contrast domain. However, measurement variability also was greater for contrast sensitivity. After correction for this variability, measurement in the contrast domain still proved to be a more sensitive (1.75x) index of optical defocus. Small-letter contrast sensitivity is a powerful technique for detecting subtle amounts of optical defocus. This adjunctive approach may be useful when there are small changes in resolution that are not detected by standard measures of visual acuity. Potential applications include evaluating the course of vision in refractive surgery, classification of cataracts, detection of corneal or macular edema, and detection of visual loss in the aging eye. Evaluation of candidates for occupations requiring unique visual abilities also may be enhanced by measuring resolution in the contrast domain.

Development of low-dose photon-counting contrast-enhanced tomosynthesis with spectral imaging.

PubMed

Schmitzberger, Florian F; Fallenberg, Eva Maria; Lawaczeck, Rüdiger; Hemmendorff, Magnus; Moa, Elin; Danielsson, Mats; Bick, Ulrich; Diekmann, Susanne; Pöllinger, Alexander; Engelken, Florian J; Diekmann, Felix

2011-05-01

To demonstrate the feasibility of low-dose photon-counting tomosynthesis in combination with a contrast agent (contrast material-enhanced tomographic mammography) for the differentiation of breast cancer. All studies were approved by the institutional review board, and all patients provided written informed consent. A phantom model with wells of iodinated contrast material (3 mg of iodine per milliliter) 1, 2, 5, 10, and 15 mm in diameter was assessed. Nine patients with malignant lesions and one with a high-risk lesion (atypical papilloma) were included (all women; mean age, 60.7 years). A multislit photon-counting tomosynthesis system was utilized (spectral imaging) to produce both low- and high-energy tomographic data (below and above the k edge of iodine, respectively) in a single scan, which allowed for dual-energy visualization of iodine. Images were obtained prior to contrast material administration and 120 and 480 seconds after contrast material administration. Four readers independently assessed the images along with conventional mammograms, ultrasonographic images, and magnetic resonance images. Glandular dose was estimated. Contrast agent was visible in the phantom model with simulated spherical tumor diameters as small as 5 mm. The average glandular dose was measured as 0.42 mGy per complete spectral imaging tomosynthesis scan of one breast. Because there were three time points (prior to contrast medium administration and 120 and 480 seconds after contrast medium administration), this resulted in a total dose of 1.26 mGy for the whole procedure in the breast with the abnormality. Seven of 10 cases were categorized as Breast Imaging Reporting and Data System score of 4 or higher by all four readers when reviewing spectral images in combination with mammograms. One lesion near the chest wall was not captured on the spectral image because of a positioning problem. The use of contrast-enhanced tomographic mammography has been demonstrated successfully in patients with promising diagnostic benefit. Further studies are necessary to fully assess diagnostic sensitivity and specificity. RSNA, 2011

Optoacoustic imaging of gold nanoparticles targeted to breast cancer cells

NASA Astrophysics Data System (ADS)

Eghtedari, Mohammad; Motamedi, Massoud; Popov, Vsevolod L.; Kotov, Nicholas A.; Oraevsky, Alexander A.

2004-07-01

Optoacoustic Tomography (OAT) is a rapidly growing technology that enables noninvasive deep imaging of biological tissues based on their light absorption. In OAT, the interaction of a pulsed laser with tissue increases the temperature of the absorbing components in a confined volume of tissue. Rapid perturbation of the temperature (<1°C) deep within tissue produces weak acoustic waves that easily travel to the surface of the tissue with minor attenuation. Abnormal angiogenesis in a malignant tumor, that increases its blood content, makes a native contrast for optoacoustic imaging; however, the application of OAT for early detection of malignant tumors requires the enhancement of optoacoustic signals originated from tumor by using an exogenous contrast agent. Due to their strong absorption, we have used gold nanoparticles (NP) as a contrast agent. 40nm spherical gold nanoparticles were attached to monoclonal antibody to target cell surface of breast cancer cells. The targeted cancer cells were implanted at depth of 5-6cm within a gelatinous object that optically resembles human breast. Experimental sensitivity measurements along with theoretical analysis showed that our optoacoustic imaging system is capable of detecting a phantom breast tumor with the volume of 0.15ml, which is composed of 25 million NP-targeted cancer cells, at a depth of 5 centimeters in vitro.

A novel technique of contrast-enhanced optical coherence tomography imaging in evaluation of clearance of lipids in human tears.

PubMed

Napoli, Pietro Emanuele; Coronella, Franco; Satta, Giovanni Maria; Fossarello, Maurizio

2014-01-01

The aim of this work was to gather preliminary data in different conditions of healthy eyes, aqueous tear deficient dry eyes, obstructive meibomian gland disease (MGD) and non-obvious obstructive MGD (NOMGD) individuals, using a new, contrast-enhanced optical coherence tomography (OCT) imaging method to evaluate the clearance of lipids in human tears. Eighty-two adult patients presenting with complaints of ocular irritation were studied for abnormalities of the ocular surface and classified as healthy (n = 21), aqueous tear deficient dry eyes (n = 20), obstructive MGD (n = 15) and NOMGD (n = 26) individuals. A lipid-based tracer, containing an oil-in-water emulsion, was used to obtain an enhanced OCT imaging of the lower tear meniscus. After instillation, a dramatic initial increase of reflectivity of the lower tear meniscus was detected by OCT, followed by a decay back to baseline values over time. Based on this finding, the clearance of lipids was measured in real-time by Fourier-domain anterior segment OCT. The differences in the clearance of lipids among the four groups as well as the correlations between symptom questionnaire score, standardized visual scale test, fluorescein break-up time, ocular surface fluorescein staining score, Schirmer I test scores were found to be statistically significant. The individual areas under the curve of the clearance of lipids calculated by the receiver operating characteristic curve technique ranged from 0.66 to 0.98, suggesting reliable sensitivity and specificity of lipid-enhanced OCT imaging. This new technique of contrast-enhanced OCT imaging of the tear film following lipid-based tracer instillation provides a measure of the clearance of lipids. The quantitative values found are in agreement with other methods of evaluation of the lacrimal system. An improvement of the clinician's ability in the diagnosis and understanding of abnormalities of the ocular surface may be achieved by this simple approach.

A multicenter, prospective study to evaluate the use of contrast stress echocardiography in early menopausal women at risk for coronary artery disease: trial design and baseline findings.

PubMed

Abdelmoneim, Sahar S; Bernier, Mathieu; Hagen, Mary E; Eifert-Rain, Susan; Bott-Kitslaar, Dalene; Wilansky, Susan; Castello, Ramon; Bhat, Gajanan; Pellikka, Patricia A; Best, Patricia J M; Hayes, Sharonne N; Mulvagh, Sharon L

2013-02-01

This multisite prospective trial, Stress Echocardiography in Menopausal Women At Risk for Coronary Artery Disease (SMART), aimed to evaluate the prognostic value of contrast stress echocardiography (CSE), coronary artery calcification (CAC), and cardiac biomarkers for prediction of cardiovascular events after 2 and 5 years in early menopausal women experiencing chest pain symptoms or risk factors. This report describes the study design, population, and initial test results at study entry. From January 2004 through September 2007, 366 early menopausal women (age 54±5 years, Framingham risk score 6.51%±4.4 %, range 1%-27%) referred for stress echocardiography were prospectively enrolled. Image quality was enhanced with an ultrasound contrast agent. Tests for cardiac biomarkers [high-sensitivity C-reactive protein (hsCRP), atrial natriuretic protein (ANP), brain natriuretic protein (BNP), endothelin (ET-1)] and cardiac computed tomography (CT) for CAC were performed. CSE (76% exercise, 24% dobutamine) was abnormal in 42 women (11.5%), and stress electrocardiogram (ECG) was positive in 22 women (6%). Rest BNP correlated weakly with stress wall motion score index (WMSI) (r=0.189, p<0.001). Neither hsCRP, ANP, endothelin, nor CAC correlated with stress WMSI. Predictors of abnormal CSE were body mass index (BMI), diabetes mellitus, family history of premature coronary artery disease (CAD), and positive stress ECG. Twenty-four women underwent clinically indicated coronary angiography (CA); 5 had obstructive (≥50%), 15 had nonobstructive (10%-49%), and 4 had no epicardial CAD. The SMART trial is designed to assess the prognostic value of CSE in early menopausal women. Independent predictors of positive CSE were BMI, diabetes mellitus, family history of premature CAD, and positive stress ECG. CAC scores and biomarkers (with the exception of rest BNP) were not correlated with CSE results. We await the follow-up data.

A Multicenter, Prospective Study to Evaluate the Use of Contrast Stress Echocardiography in Early Menopausal Women at Risk for Coronary Artery Disease: Trial Design and Baseline Findings

PubMed Central

Abdelmoneim, Sahar S.; Bernier, Mathieu; Hagen, Mary E.; Eifert-Rain, Susan; Bott-Kitslaar, Dalene; Wilansky, Susan; Castello, Ramon; Bhat, Gajanan; Pellikka, Patricia A.; Best, Patricia J. M.; Hayes, Sharonne N.

2013-01-01

Abstract Aims This multisite prospective trial, Stress Echocardiography in Menopausal Women At Risk for Coronary Artery Disease (SMART), aimed to evaluate the prognostic value of contrast stress echocardiography (CSE), coronary artery calcification (CAC), and cardiac biomarkers for prediction of cardiovascular events after 2 and 5 years in early menopausal women experiencing chest pain symptoms or risk factors. This report describes the study design, population, and initial test results at study entry. Methods From January 2004 through September 2007, 366 early menopausal women (age 54±5 years, Framingham risk score 6.51%±4.4 %, range 1%–27%) referred for stress echocardiography were prospectively enrolled. Image quality was enhanced with an ultrasound contrast agent. Tests for cardiac biomarkers [high-sensitivity C-reactive protein (hsCRP), atrial natriuretic protein (ANP), brain natriuretic protein (BNP), endothelin (ET-1)] and cardiac computed tomography (CT) for CAC were performed. Results CSE (76% exercise, 24% dobutamine) was abnormal in 42 women (11.5%), and stress electrocardiogram (ECG) was positive in 22 women (6%). Rest BNP correlated weakly with stress wall motion score index (WMSI) (r=0.189, p<0.001). Neither hsCRP, ANP, endothelin, nor CAC correlated with stress WMSI. Predictors of abnormal CSE were body mass index (BMI), diabetes mellitus, family history of premature coronary artery disease (CAD), and positive stress ECG. Twenty-four women underwent clinically indicated coronary angiography (CA); 5 had obstructive (≥50%), 15 had nonobstructive (10%–49%), and 4 had no epicardial CAD. Conclusions The SMART trial is designed to assess the prognostic value of CSE in early menopausal women. Independent predictors of positive CSE were BMI, diabetes mellitus, family history of premature CAD, and positive stress ECG. CAC scores and biomarkers (with the exception of rest BNP) were not correlated with CSE results. We await the follow-up data. PMID:23398128

Olfactory function in psychotic disorders: Insights from neuroimaging studies

PubMed Central

Good, Kimberley P; Sullivan, Randii Lynn

2015-01-01

Olfactory deficits on measures of identification, familiarity, and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to remain intact while the data on hedonics and detection threshold are inconsistent. Despite the behavioral abnormalities noted, no specific regional brain hypoactivity has been identified in psychosis patients, for any of the olfactory domains. However, an intriguing finding emerged from this review in that the amygdala and pirifom cortices were not noted to be abnormal in hedonic processing (nor was the amygdala identified abnormal in any study) in psychotic disorders. This finding is in contrast to the literature in healthy individuals, in that this brain region is strongly implicated in olfactory processing (particularly for unpleasant odorants). Secondary olfactory cortex (orbitofrontal cortices, thalamus, and insula) was abnormally activated in the studies examined, particularly for hedonic processing. Further research, using consistent methodology, is required for better understanding the neurobiology of olfactory deficits. The authors suggest taking age and sex differences into consideration and further contrasting olfactory subgroups (impaired vs intact) to better our understanding of the heterogeneity of psychotic disorders. PMID:26110122

The Ohio Contrast Cards: Visual Performance in a Pediatric Low-vision Site

PubMed Central

Hopkins, Gregory R.; Dougherty, Bradley E.; Brown, Angela M.

2017-01-01

SIGNIFICANCE This report describes the first clinical use of the Ohio Contrast Cards, a new test that measures the maximum spatial contrast sensitivity of low-vision patients who cannot recognize and identify optotypes and for whom the spatial frequency of maximum contrast sensitivity is unknown. PURPOSE To compare measurements of the Ohio Contrast Cards to measurements of three other vision tests and a vision-related quality-of-life questionnaire obtained on partially sighted students at Ohio State School for the Blind. METHODS The Ohio Contrast Cards show printed square-wave gratings at very low spatial frequency (0.15 cycle/degree). The patient looks to the left/right side of the card containing the grating. Twenty-five students (13 to 20 years old) provided four measures of visual performance: two grating card tests (the Ohio Contrast Cards and the Teller Acuity Cards) and two letter charts (the Pelli-Robson contrast chart and the Bailey-Lovie acuity chart). Spatial contrast sensitivity functions were modeled using constraints from the grating data. The Impact of Vision Impairment on Children questionnaire measured vision-related quality of life. RESULTS Ohio Contrast Card contrast sensitivity was always less than 0.19 log10 units below the maximum possible contrast sensitivity predicted by the model; average Pelli-Robson letter contrast sensitivity was near the model prediction, but 0.516 log10 units below the maximum. Letter acuity was 0.336 logMAR below the grating acuity results. The model estimated the best testing distance in meters for optimum Pelli-Robson contrast sensitivity from the Bailey-Lovie acuity as distance = 1.5 − logMAR for low-vision patients. Of the four vision tests, only Ohio Contrast Card contrast sensitivity was independently and statistically significantly correlated with students' quality of life. CONCLUSIONS The Ohio Contrast Cards combine a grating stimulus, a looking indicator behavior, and contrast sensitivity measurement. They show promise for the clinical objective of advising the patient and his/her caregivers about the success the patient is likely to enjoy in tasks of everyday life. PMID:28972542

An approach to analyze the breast tissues in infrared images using nonlinear adaptive level sets and Riesz transform features.

PubMed

Prabha, S; Suganthi, S S; Sujatha, C M

2015-01-01

Breast thermography is a potential imaging method for the early detection of breast cancer. The pathological conditions can be determined by measuring temperature variations in the abnormal breast regions. Accurate delineation of breast tissues is reported as a challenging task due to inherent limitations of infrared images such as low contrast, low signal to noise ratio and absence of clear edges. Segmentation technique is attempted to delineate the breast tissues by detecting proper lower breast boundaries and inframammary folds. Characteristic features are extracted to analyze the asymmetrical thermal variations in normal and abnormal breast tissues. An automated analysis of thermal variations of breast tissues is attempted using nonlinear adaptive level sets and Riesz transform. Breast thermal images are initially subjected to Stein's unbiased risk estimate based orthonormal wavelet denoising. These denoised images are enhanced using contrast-limited adaptive histogram equalization method. The breast tissues are then segmented using non-linear adaptive level set method. The phase map of enhanced image is integrated into the level set framework for final boundary estimation. The segmented results are validated against the corresponding ground truth images using overlap and regional similarity metrics. The segmented images are further processed with Riesz transform and structural texture features are derived from the transformed coefficients to analyze pathological conditions of breast tissues. Results show that the estimated average signal to noise ratio of denoised images and average sharpness of enhanced images are improved by 38% and 6% respectively. The interscale consideration adopted in the denoising algorithm is able to improve signal to noise ratio by preserving edges. The proposed segmentation framework could delineate the breast tissues with high degree of correlation (97%) between the segmented and ground truth areas. Also, the average segmentation accuracy and sensitivity are found to be 98%. Similarly, the maximum regional overlap between segmented and ground truth images obtained using volume similarity measure is observed to be 99%. Directionality as a feature, showed a considerable difference between normal and abnormal tissues which is found to be 11%. The proposed framework for breast thermal image analysis that is aided with necessary preprocessing is found to be useful in assisting the early diagnosis of breast abnormalities.

Simultaneous and Noninvasive Imaging of Cerebral Oxygen Metabolic Rate, Blood Flow and Oxygen Extraction Fraction in Stroke Mice

PubMed Central

Zhu, Xiao-Hong; Chen, James; Tu, Tsang-Wei; Chen, Wei; Song, Sheng-Kwei

2012-01-01

Many brain diseases have been linked to abnormal oxygen metabolism and blood perfusion; nevertheless, there is still a lack of robust diagnostic tools for directly imaging cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF), as well as the oxygen extraction fraction (OEF) that reflects the balance between CMRO2 and CBF. This study employed the recently developed in vivo 17O MR spectroscopic imaging to simultaneously assess CMRO2, CBF and OEF in the brain using a preclinical middle cerebral arterial occlusion mouse model with a brief inhalation of 17O-labeled oxygen gas. The results demonstrated high sensitivity and reliability of the noninvasive 17O-MR approach for rapidly imaging CMRO2, CBF and OEF abnormalities in the ischemic cortex of the MCAO mouse brain. It was found that in the ischemic brain regions both CMRO2 and CBF were substantially lower than that of intact brain regions, even for the mildly damaged brain regions that were unable to be clearly identified by the conventional MRI. In contrast, OEF was higher in the MCAO affected brain regions. This study demonstrates a promising 17O MRI technique for imaging abnormal oxygen metabolism and perfusion in the diseased brain regions. This 17O MRI technique is advantageous because of its robustness, simplicity, noninvasiveness and reliability: features that are essential to potentially translate it to human patients for early diagnosis and monitoring of treatment efficacy. PMID:23000789

Simultaneous and noninvasive imaging of cerebral oxygen metabolic rate, blood flow and oxygen extraction fraction in stroke mice.

PubMed

Zhu, Xiao-Hong; Chen, James M; Tu, Tsang-Wei; Chen, Wei; Song, Sheng-Kwei

2013-01-01

Many brain diseases have been linked to abnormal oxygen metabolism and blood perfusion; nevertheless, there is still a lack of robust diagnostic tools for directly imaging cerebral metabolic rate of oxygen (CMRO(2)) and cerebral blood flow (CBF), as well as the oxygen extraction fraction (OEF) that reflects the balance between CMRO(2) and CBF. This study employed the recently developed in vivo (17)O MR spectroscopic imaging to simultaneously assess CMRO(2), CBF and OEF in the brain using a preclinical middle cerebral arterial occlusion mouse model with a brief inhalation of (17)O-labeled oxygen gas. The results demonstrated high sensitivity and reliability of the noninvasive (17)O-MR approach for rapidly imaging CMRO(2), CBF and OEF abnormalities in the ischemic cortex of the MCAO mouse brain. It was found that in the ischemic brain regions both CMRO(2) and CBF were substantially lower than that of intact brain regions, even for the mildly damaged brain regions that were unable to be clearly identified by the conventional MRI. In contrast, OEF was higher in the MCAO affected brain regions. This study demonstrates a promising (17)O MRI technique for imaging abnormal oxygen metabolism and perfusion in the diseased brain regions. This (17)O MRI technique is advantageous because of its robustness, simplicity, noninvasiveness and reliability: features that are essential to potentially translate it to human patients for early diagnosis and monitoring of treatment efficacy. Copyright © 2012 Elsevier Inc. All rights reserved.

Visual Contrast Sensitivity in Early-Stage Parkinson's Disease.

PubMed

Ming, Wendy; Palidis, Dimitrios J; Spering, Miriam; McKeown, Martin J

2016-10-01

Visual impairments are frequent in Parkinson's disease (PD) and impact normal functioning in daily activities. Visual contrast sensitivity is a powerful nonmotor sign for discriminating PD patients from controls. However, it is usually assessed with static visual stimuli. Here we examined the interaction between perception and eye movements in static and dynamic contrast sensitivity tasks in a cohort of mildly impaired, early-stage PD patients. Patients (n = 13) and healthy age-matched controls (n = 12) viewed stimuli of various spatial frequencies (0-8 cyc/deg) and speeds (0°/s, 10°/s, 30°/s) on a computer monitor. Detection thresholds were determined by asking participants to adjust luminance contrast until they could just barely see the stimulus. Eye position was recorded with a video-based eye tracker. Patients' static contrast sensitivity was impaired in the intermediate spatial-frequency range and this impairment correlated with fixational instability. However, dynamic contrast sensitivity and patients' smooth pursuit were relatively normal. An independent component analysis revealed contrast sensitivity profiles differentiating patients and controls. Our study simultaneously assesses perceptual contrast sensitivity and eye movements in PD, revealing a possible link between fixational instability and perceptual deficits. Spatiotemporal contrast sensitivity profiles may represent an easily measurable metric as a component of a broader combined biometric for nonmotor features observed in PD.

Evaluation of Screening for Retinopathy of Prematurity by ROPtool or a Lay Reader.

PubMed

Abbey, Ashkan M; Besirli, Cagri G; Musch, David C; Andrews, Chris A; Capone, Antonio; Drenser, Kimberly A; Wallace, David K; Ostmo, Susan; Chiang, Michael; Lee, Paul P; Trese, Michael T

2016-02-01

To determine if (1) tortuosity assessment by a computer program (ROPtool, developed at the University of North Carolina, Chapel Hill, and Duke University, and licensed by FocusROP) that traces retinal blood vessels and (2) assessment by a lay reader are comparable with assessment by a panel of 3 retinopathy of prematurity (ROP) experts for remote clinical grading of vascular abnormalities such as plus disease. Validity and reliability analysis of diagnostic tools. Three hundred thirty-five fundus images of prematurely born infants. Three hundred thirty-five fundus images of prematurely born infants were obtained by neonatal intensive care unit nurses. A panel of 3 ROP experts graded 84 images showing vascular dilatation, tortuosity, or both and 251 images showing no evidence of vascular abnormalities. These images were sent electronically to an experienced lay reader who independently graded them for vascular abnormalities. The images also were analyzed using the ROPtool, which assigns a numerical value to the level of vascular abnormality and tortuosity present in each of 4 quadrants or sectors. The ROPtool measurements of vascular abnormalities were graded and compared with expert panel grades with a receiver operating characteristic (ROC) curve. Grades between human readers were cross-tabulated. The area under the ROC curve was calculated for the ROPtool, and sensitivity and specificity were computed for the lay reader. Measurements of vascular abnormalities by ROPtool and grading of vascular abnormalities by 3 ROP experts and 1 experienced lay reader. The ROC curve for ROPtool's tortuosity assessment had an area under the ROC curve of 0.917. Using a threshold value of 4.97 for the second most tortuous quadrant, ROPtool's sensitivity was 91% and its specificity was 82%. Lay reader sensitivity and specificity were 99% and 73%, respectively, and had high reliability (κ, 0.87) in repeated measurements. ROPtool had very good accuracy for detection of vascular abnormalities suggestive of plus disease when compared with expert physician graders. The lay reader's results showed excellent sensitivity and good specificity when compared with those of the expert graders. These options for remote reading of images to detect vascular abnormalities deserve consideration in the quest to use telemedicine with remote reading for efficient delivery of high-quality care and to detect infants requiring bedside examination. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Prognostic Utility of Stress Testing and Cardiac Biomarkers in Menopausal Women at Low to Intermediate Risk for Coronary ARTery Disease (SMART Study): 5-Year Outcome.

PubMed

Abdelmoneim, Sahar S; Ball, Caroline A; Mantovani, Francesca; Hagen, Mary E; Eifert-Rain, Susan; Wilansky, Susan; Castello, Ramon; Pellikka, Patricia A; Best, Patricia J M; Mulvagh, Sharon L

2018-05-01

In women with low to intermediate risk of coronary artery disease (CAD), prognostic detection strategies have been controversial. We present the follow-up data of the SMART trial in peri/postmenopausal women at low to intermediate risk of CAD. To determine the value of contrast stress echocardiography (CSE), stress electrocardiogram (sECG), and serum biomarkers for prediction of cardiovascular events (CE) in peri/postmenopausal women at low to intermediate risk of CAD. From January 2004 to August 2007, 400 peri/postmenopausal women were prospectively enrolled. All women had detailed risk factor assessment, and underwent simultaneous CSE (Definity ® , Lantheus Medical Imaging) and sECG. Laboratories included brain natriuretic peptide (BNP), atrial natriuretic peptide, endothelin, and high sensitivity C-reactive protein. Wall motion score index was based on a 16-segment model. Abnormal CSE was defined as new or worsening wall motion abnormality at stress, while abnormal sECG was ≥1 mm horizontal/downsloping ST segment depression/elevation (80 mseconds duration). Self-reported outcome data were collected from a mailed Women's Heart Clinic Questionnaire. CE outcomes included all-cause mortality, nonfatal myocardial infarction (MI), heart failure, chest pain hospitalization or development of typical angina (CP), and revascularization (REVASC). Adjusted Cox proportional hazard ratios (HR; 95% confidence intervals) were reported. A total of 366 women (54.4 ± 5.5 years, Framingham risk 6.5% ± 4.4%) completed simultaneous CSE and sECG. Forty-two (11.5%) had abnormal CSE, while sECG was abnormal in 22 (6%) women. Follow-up (4.4 ± 1.2 years) was available in 315/366 (86%) women (78% exercise-CSE, 22% dobutamine-CSE). In those who completed follow-up, CSE was abnormal in 33 women (10.5%) and sECG was abnormal in 21 (6.7%). In 33 women with abnormal CSE, sECG was abnormal in 7 (21.2%) and normal in 26 (79%), p = 0.0004. CE occurred in 27 (8.6%) women: 8 all-cause mortality, 2 nonfatal MI, 13 CP, and 4 REVASC. CE occurred in 21% versus 7% of women with abnormal versus normal CSE, p = 0.014 and 38% versus 6% of women with abnormal versus normal sECG, p < 0.0001. Rest BNP was higher in women with CE versus those without (p = 0.018). Abnormal sECG and abnormal CSE were associated with CE, while only abnormal sECG was an independent predictor of CE (adjusted HR 10.3 [1.9-61.4], p = 0.007). Of the laboratory results, only BNP was associated with CE (adjusted HR 2.9 [1.1-7.3], p = 0.028). sECG and rest BNP were independent predictors of subsequent CE within 5 years in peri/postmenopausal women at low to intermediate risk of CAD.

Abnormal enhancement against interference inhibition for few-cycle pulses propagating in dense media

NASA Astrophysics Data System (ADS)

Chen, Yue-Yue; Feng, Xun-Li; Xu, Zhi-Zhan; Liu, Chengpu

2016-04-01

We numerically study the reflected spectrum of a few-cycle pulse propagating through an ultrathin resonant medium. According to the classical interference theory, a destructive interference dip is expected at the carrier frequency ωp for a half-wavelength medium. In contrast, an abnormal enhanced spike appears instead. The origin of such an abnormal enhancement is attributed to the coherent transient effects. In addition, its scaling laws versus medium length, pulse area and duration are obtained, which follow simple rules.

Staging of breast cancer and the advanced applications of digital mammogram: what the physician needs to know?

PubMed

Helal, Maha H; Mansour, Sahar M; Zaglol, Mai; Salaleldin, Lamia A; Nada, Omniya M; Haggag, Marwa A

2017-03-01

To study the role of advanced applications of digital mammogram, whether contrast-enhanced spectral mammography (CESM) or digital breast tomosynthesis (DBT), in the "T" staging of histologically proven breast cancer before planning for treatment management. In this prospective analysis, we evaluated 98 proved malignant breast masses regarding their size, multiplicity and the presence of associated clusters of microcalcifications. Evaluation methods included digital mammography (DM), 3D tomosynthesis and CESM. Traditional DM was first performed then in a period of 10-14-day interval; breast tomosynthesis and contrast-based mammography were performed for the involved breast only. Views at tomosynthesis were acquired in a "step-and-shoot" tube motion mode to produce multiple (11-15), low-dose images and in contrast-enhanced study, low-energy (22-33 kVp) and high-energy (44-49 kVp) exposures were taken after the i.v. injection of the contrast agent. Operative data were the gold standard reference. Breast tomosynthesis showed the highest accuracy in size assessment (n = 69, 70.4%) than contrast-enhanced (n = 49, 50%) and regular mammography (n = 59, 60.2%). Contrast-enhanced mammography presented the least performance in assessing calcifications, yet it was most sensitive in the detection of multiplicity (92.3%), followed by tomosynthesis (77%) and regular mammography (53.8%). The combined analysis of the three modalities provided an accuracy of 74% in the "T" staging of breast cancer. The combined application of tomosynthesis and contrast-enhanced digital mammogram enhanced the performance of the traditional DM and presented an informative method in the staging of breast cancer. Advances in knowledge: Staging and management planning of breast cancer can divert according to tumour size, multiplicity and the presence of microcalcifications. DBT shows sharp outlines of the tumour with no overlap tissue and spots microcalcifications. Contrast-enhanced spectral mammogram shows the extent of abnormal contrast uptake and detects multiplicity. Integrated analysis provides optimal findings for proper "T" staging of breast cancer.

Increased sensitivity to positive social stimuli in monozygotic twins at risk of bipolar vs. unipolar disorder.

PubMed

Kærsgaard, S; Meluken, I; Kessing, L V; Vinberg, M; Miskowiak, K W

2018-05-01

Abnormalities in affective cognition are putative endophenotypes for bipolar and unipolar disorders but it is unclear whether some abnormalities are disorder-specific. We therefore investigated affective cognition in monozygotic twins at familial risk of bipolar disorder relative to those at risk of unipolar disorder and to low-risk twins. Seventy monozygotic twins with a co-twin history of bipolar disorder (n = 11), of unipolar disorder (n = 38) or without co-twin history of affective disorder (n = 21) were included. Variables of interest were recognition of and vigilance to emotional faces, emotional reactivity and -regulation in social scenarios and non-affective cognition. Twins at familial risk of bipolar disorder showed increased recognition of low to moderate intensity of happy facial expressions relative to both unipolar disorder high-risk twins and low-risk twins. Bipolar disorder high-risk twins also displayed supraliminal attentional avoidance of happy faces compared with unipolar disorder high-risk twins and greater emotional reactivity in positive and neutral social scenarios and less reactivity in negative social scenarios than low-risk twins. In contrast with our hypothesis, there was no negative bias in unipolar disorder high-risk twins. There were no differences between the groups in demographic characteristics or non-affective cognition. The modest sample size limited the statistical power of the study. Increased sensitivity and reactivity to positive social stimuli may be a neurocognitive endophenotype that is specific for bipolar disorder. If replicated in larger samples, this 'positive endophenotype' could potentially aid future diagnostic differentiation between unipolar and bipolar disorder. Copyright © 2018 Elsevier B.V. All rights reserved.

Reduced sensitivity of the N400 and late positive component to semantic congruity and word repetition in left temporal lobe epilepsy.

PubMed

Olichney, John M; Riggins, Brock R; Hillert, Dieter G; Nowacki, Ralph; Tecoma, Evelyn; Kutas, Marta; Iragui, Vicente J

2002-07-01

We studied 14 patients with well-characterized refractory temporal lobe epilepsy (TLE), 7 with right temporal lobe epilepsy (RTE) and 7 with left temporal lobe epilepsy (LTE), on a word repetition ERP experiment. Much prior literature supports the view that patients with left TLE are more likely to develop verbal memory deficits, often attributable to left hippocampal sclerosis. Our main objectives were to test if abnormalities of the N400 or Late Positive Component (LPC, P600) were associated with a left temporal seizure focus, or left temporal lobe dysfunction. A minimum of 19 channels of EEG/EOG data were collected while subjects performed a semantic categorization task. Auditory category statements were followed by a visual target word, which were 50% "congruous" (category exemplars) and 50% "incongruous" (non-category exemplars) with the preceding semantic context. These auditory-visual pairings were repeated pseudo-randomly at time intervals ranging from approximately 10-140 seconds later. The ERP data were submitted to repeated-measures ANOVAs, which showed the RTE group had generally normal effects of word repetition on the LPC and the N400. Also, the N400 component was larger to incongruous than congruous new words, as is normally the case. In contrast, the LTE group did not have statistically significant effects of either word repetition or congruity on their ERPs (N400 or LPC), suggesting that this ERP semantic categorization paradigm is sensitive to left temporal lobe dysfunction. Further studies are ongoing to determine if these ERP abnormalities predict hippocampal sclerosis on histopathology, or outcome after anterior temporal lobectomy.

The influence of L-opsin gene polymorphisms and neural ageing on spatio-chromatic contrast sensitivity in 20-71 year olds.

PubMed

Dees, Elise W; Gilson, Stuart J; Neitz, Maureen; Baraas, Rigmor C

2015-11-01

Chromatic contrast sensitivity may be a more sensitive measure of an individual's visual function than achromatic contrast sensitivity. Here, the first aim was to quantify individual- and age-related variations in chromatic contrast sensitivity to a range of spatial frequencies for stimuli along two complementary directions in color space. The second aim was to examine whether polymorphisms at specific amino acid residues of the L- and M-opsin genes (OPN1LW and OPN1MW) known to affect spectral tuning of the photoreceptors could influence spatio-chromatic contrast sensitivity. Chromatic contrast sensitivity functions were measured in 50 healthy individuals (20-71 years) employing a novel pseudo-isochromatic grating stimulus. The spatio-chromatic contrast sensitivity functions were found to be low pass for all subjects, independent of age and color vision. The results revealed a senescent decline in spatio-chromatic contrast sensitivity. There were considerable between-individual differences in sensitivity within each age decade for individuals 49 years old or younger, and age did not predict sensitivity for these age decades alone. Forty-six subjects (including a color deficient male and eight female carriers) were genotyped for L- and M-opsin genes. The Ser180Ala polymorphisms on the L-opsin gene were found to influence the subject's color discrimination and their sensitivity to spatio-chromatic patterns. The results expose the significant role of neural and genetic factors in the deterioration of visual function with increasing age. Copyright © 2015 Elsevier Ltd. All rights reserved.

The impact of slice-reduced computed tomography on histogram-based densitometry assessment of lung fibrosis in patients with systemic sclerosis

PubMed Central

Maurer, Britta; Suliman, Yossra A.; Morsbach, Fabian; Distler, Oliver; Frauenfelder, Thomas

2018-01-01

Background To evaluate usability of slice-reduced sequential computed tomography (CT) compared to standard high-resolution CT (HRCT) in patients with systemic sclerosis (SSc) for qualitative and quantitative assessment of interstitial lung disease (ILD) with respect to (I) detection of lung parenchymal abnormalities, (II) qualitative and semiquantitative visual assessment, (III) quantification of ILD by histograms and (IV) accuracy for the 20%-cut off discrimination. Methods From standard chest HRCT of 60 SSc patients sequential 9-slice-computed tomography (reduced HRCT) was retrospectively reconstructed. ILD was assessed by visual scoring and quantitative histogram parameters. Results from standard and reduced HRCT were compared using non-parametric tests and analysed by univariate linear regression analyses. Results With respect to the detection of parenchymal abnormalities, only the detection of intrapulmonary bronchiectasis was significantly lower in reduced HRCT compared to standard HRCT (P=0.039). No differences were found comparing visual scores for fibrosis severity and extension from standard and reduced HRCT (P=0.051–0.073). All scores correlated significantly (P<0.001) to histogram parameters derived from both, standard and reduced HRCT. Significant higher values of kurtosis and skewness for reduced HRCT were found (both P<0.001). In contrast to standard HRCT histogram parameters from reduced HRCT showed significant discrimination at cut-off 20% fibrosis (sensitivity 88% kurtosis and skewness; specificity 81% kurtosis and 86% skewness; cut-off kurtosis ≤26, cut-off skewness ≤4; both P<0.001). Conclusions Reduced HRCT is a robust method to assess lung fibrosis in SSc with minimal radiation dose with no difference in scoring assessment of lung fibrosis severity and extension in comparison to standard HRCT. In contrast to standard HRCT histogram parameters derived from the approach of reduced HRCT could discriminate at a threshold of 20% lung fibrosis with high sensitivity and specificity. Hence it might be used to detect early disease progression of lung fibrosis in context of monitoring and treatment of SSc patients. PMID:29850118

Incidence and Long-term Outcomes of the HIV-Neuroretinal Disorder in Patients with the Acquired Immunodeficiency Syndrome

PubMed Central

Jabs, Douglas A.; Drye, Lea; Van Natta, Mark L.; Thorne, Jennifer E.; Holland, Gary N.

2014-01-01

Objectives Patients with the acquired immunodeficiency syndrome (AIDS) have an abnormality of retina/optic nerve function, manifested as decreased contrast sensitivity (in the absence of ocular opportunistic infections or media opacity), abnormalities on automated perimetry, and loss of retinal nerve fiber layer, even among those with good visual acuity, termed the HIV-neuroretinal disorder. The objectives of this study were to determine the prevalence, incidence, risk factors for, and outcomes of HIV-neuroretinal disorder. Design Prospective cohort study Participants 1822 patients with AIDS without ocular infections or media opacities. Methods Patients with HIV-neuroretinal disorder were identified by a contrast sensitivity < 1.50 log units in either eye in the absence of ocular opportunistic infections or media opacity. Main outcome measures Incidence of HIV-neuroretinal disorder, mortality, visual impairment (visual acuity 20/50 or worse), and blindness (20/200 or worse) on logarithmic visual acuity charts. Results Sixteen percent of participants had HIV-neuroretinal disorder at enrollment. The estimated cumulative incidence by 20 years after AIDS diagnosis was 51% (95% confidence interval [CI] 46%–55%). HIV-neuroretinal disorder was more common in women and African American persons. Risk factors for it included hepatitis C infection, low CD4+ T cells, and detectable HIV RNA in the blood. Patients with HIV neuroretinal disorder had a 70% excess mortality vs. those without it, even after adjusting for CD4+ T cells and HIV load (hazard ratio=1.7, 95% CI= 1.3–2.1, P<0.0001). Patients with HIV-neuroretinal disorder had increased risks of bilateral visual impairment (hazard ratio=6.5, 95% CI=2.6–10.6, P<0.0001) and blindness (hazard ratio=5.9, 95% CI=2.8–13.7, P=0.01) vs. those without HIV neuroretinal disorder. Conclusions HIV-neuroretinal disorder is a common finding among patients with AIDS, and it is associated with an increased mortality and an increased risk of visual impairment. Successful antiretroviral therapy decreases but does not eliminate the risk of HIV-neuroretinal disorder. PMID:25600199

Contrast Sensitivity With a Subretinal Prosthesis and Implications for Efficient Delivery of Visual Information

PubMed Central

Goetz, Georges; Smith, Richard; Lei, Xin; Galambos, Ludwig; Kamins, Theodore; Mathieson, Keith; Sher, Alexander; Palanker, Daniel

2015-01-01

Purpose To evaluate the contrast sensitivity of a degenerate retina stimulated by a photovoltaic subretinal prosthesis, and assess the impact of low contrast sensitivity on transmission of visual information. Methods We measure ex vivo the full-field contrast sensitivity of healthy rat retina stimulated with white light, and the contrast sensitivity of degenerate rat retina stimulated with a subretinal prosthesis at frequencies exceeding flicker fusion (>20 Hz). Effects of eye movements on retinal ganglion cell (RGC) activity are simulated using a linear–nonlinear model of the retina. Results Retinal ganglion cells adapt to high frequency stimulation of constant intensity, and respond transiently to changes in illumination of the implant, exhibiting responses to ON-sets, OFF-sets, and both ON- and OFF-sets of light. The percentage of cells with an OFF response decreases with progression of the degeneration, indicating that OFF responses are likely mediated by photoreceptors. Prosthetic vision exhibits reduced contrast sensitivity and dynamic range, with 65% contrast changes required to elicit responses, as compared to the 3% (OFF) to 7% (ON) changes with visible light. The maximum number of action potentials elicited with prosthetic stimulation is at most half of its natural counterpart for the ON pathway. Our model predicts that for most visual scenes, contrast sensitivity of prosthetic vision is insufficient for triggering RGC activity by fixational eye movements. Conclusions Contrast sensitivity of prosthetic vision is 10 times lower than normal, and dynamic range is two times below natural. Low contrast sensitivity and lack of OFF responses hamper delivery of visual information via a subretinal prosthesis. PMID:26540657

Perceptual Learning Improves Contrast Sensitivity of V1 Neurons in Cats

PubMed Central

Hua, Tianmiao; Bao, Pinglei; Huang, Chang-Bing; Wang, Zhenhua; Xu, Jinwang

2010-01-01

Summary Background Perceptual learning has been documented in adult humans over a wide range of tasks. Although the often observed specificity of learning is generally interpreted as evidence for training-induced plasticity in early cortical areas, physiological evidence for training-induced changes in early visual cortical areas is modest, despite reports of learning-induced changes of cortical activities in fMRI studies. To reveal the physiological bases of perceptual learning, we combined psychophysical measurements with extracellular single-unit recording under anesthetized preparations, and examined the effects of training in grating orientation identification on both perceptual and neuronal contrast sensitivity functions of cats. Results We have found that training significantly improved perceptual contrast sensitivity of the cats to gratings with the spatial frequencies near the ‘trained’ spatial frequency, with stronger effects in the trained eye. Consistent with behavioral assessments, the mean contrast sensitivity of neurons recorded from V1 of the trained cats was significantly higher than that of neurons recorded from the untrained cats. Furthermore, in the trained cats, the contrast sensitivity of V1 neurons responding preferentially to stimuli presented via the trained eyes was significantly greater than that of neurons responding preferentially to stimuli presented via the ‘untrained’ eyes. The effect was confined to the trained spatial frequencies. In both trained and untrained cats, the neuronal contrast sensitivity functions derived from the contrast sensitivity of the individual neurons were highly correlated with behaviorally determined perceptual contrast sensitivity functions. Conclusions We suggest that training-induced neuronal contrast-gain in area V1 underlies behaviorally determined perceptual contrast sensitivity improvements. PMID:20451388

Evaluation of the thoraco-laryngeal reflex ('slap test') as an aid to the diagnosis of cervical spinal cord and brainstem disease in horses.

PubMed

Newton-Clarke, M J; Divers, T J; Delahunta, A; Mohammed, H O

1994-09-01

A study was conducted over a 12 month period to assess the specificity and sensitivity of the 'slap test', using endoscopic evaluation, in the detection of cervical spinal cord and caudal brainstem lesions in horses. Fifteen ataxic horses were subjected to the 'slap test' and subsequently examined post mortem. Twelve out of the 15 had histopathological lesions consistent with their clinical signs. Thirteen horses with no history of neurological dysfunction and no histopathological evidence of cervical spinal cord or brainstem disease were used as controls. The laryngeal adductory responses exhibited by all horses were filmed and later scored independently by 3 assessors. The proportion of animals diagnosed with cervical spinal cord and/or brainstem disease, defined by histopathological criteria, was found to be statistically similar to the proportion with abnormal 'slap test' responses, using the McNemar chi-Square test. Despite statistical significance between proportions, sensitivity of the 'slap test' was low, 50% for the left side on both days and 58% for the right side. Specificity was higher, 69% (Day 1) and 75% (Day 2) for the left side and 75% (Day 1) and 69% (Day 2) for the right side. In contrast to this, conventional neurological examination was found to be 100% sensitive and 81% specific in the detection of lesions of histopathological significance in the cervical spinal cord/caudal brainstem. Agreement between scores for the 'slap test' from the same assessor on different days was good, with values for kappa of 0.59 to 0.85. In contrast, agreement between assessors on the 'slap test' score was poor, with kappa 0.35.(ABSTRACT TRUNCATED AT 250 WORDS)

Food sensitive enteropathy: overview and update.

PubMed

Walker-Smith, J

1994-10-01

There are two types of food sensitive enteropathy; permanent and temporary. Celiac disease belongs to the former, the temporary food sensitive enteropathies of early childhood to the latter. A food sensitive enteropathy is characterized by an abnormal small intestinal mucosa while having the offending food in the diet; the abnormality is reversed by an elimination diet, only to recur once more on challenge with the relevant food. These disorders are temporary and may follow gastroenteritis. Cow's milk sensitive enteropathy is the most frequent and best known example but soy protein, egg, fish, chicken meat, ground rice and probably gluten may also temporarily damage the small intestinal mucosa in infancy. Treatment is with an elimination diet and protein hydrolysates as a cow's milk substitute. The reason why these enteropathies are temporary has not yet been established.

Abnormal gel flotation caused by contrast media during adrenal vein sampling.

PubMed

Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Gelati, Matteo; Bassi, Antonella; Contro, Alberto; Pizzolo, Francesca; Guidi, Gian Cesare

2016-10-15

During adrenal venous sampling (AVS) procedure, radiologists administer a contrast agent via the catheter to visualize the proper catheter position. A patient with primary aldosteronism diagnostic-hypothesis was admitted for AVS. A venogram was performed to
confirm the catheter's position with 2mL of Iopamidol 300 mg/mL. Samples were collected with syringe connected to a hydrophilic coated catheter by low-pressure aspiration from each of the four collection sites: inferior vena cava in the suprarenal portion, inferior vena cava in the infrarenal portion, left adrenal vein, and right adrenal vein; then immediately transferred from syringe to tubes with gel separator. All tubes were centrifuged at 1200 x g for 10 minutes. At the end of centrifugation process, primary blood tubes containing blood from inferior vena cava and left adrenal vein exhibited the standard gel separator barrier, while tubes from right adrenal vein showed abnormal flotation of gel separator. The radiologist confirmed the usage of 2.6 mL instead of 2.0 mL of Iopamidol 300 mg/mL. This iodinated contrast media, with 1.33 g/cm 3 of density, was used close to the right adrenal vein due to some difficulty to access it. The abnormal flotation of gel separator in samples taken from right adrenal vein can be explained by the usage of the iodinated
contrast media. We suggest using plain-tubes (without gel separator) for AVS in order to avoid preanalytical nonconformities. Moreover, a blood volume equivalent to twice the catheter extension should be discarded to eliminate residual contrast media before collection of samples for laboratory assays.

Journal Club: Comparison of assessment of preoperative pulmonary vasculature in patients with non-small cell lung cancer by non-contrast- and 4D contrast-enhanced 3-T MR angiography and contrast-enhanced 64-MDCT.

PubMed

Ohno, Yoshiharu; Nishio, Mizuho; Koyama, Hisanobu; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Seki, Shinichiro; Sugimura, Kazuro

2014-03-01

The purpose of this article is to prospectively and directly compare the capabilities of non-contrast-enhanced MR angiography (MRA), 4D contrast-enhanced MRA, and contrast-enhanced MDCT for assessing pulmonary vasculature in patients with non-small cell lung cancer (NSCLC) before surgical treatment. A total of 77 consecutive patients (41 men and 36 women; mean age, 71 years) with pathologically proven and clinically assessed stage I NSCLC underwent thin-section contrast-enhanced MDCT, non-contrast-enhanced and contrast-enhanced MRA, and surgical treatment. The capability for anomaly assessment of the three methods was independently evaluated by two reviewers using a 5-point visual scoring system, and final assessment for each patient was made by consensus of the two readers. Interobserver agreement for pulmonary arterial and venous assessment was evaluated with the kappa statistic. Then, sensitivity, specificity, and accuracy for the detection of anomalies were directly compared among the three methods by use of the McNemar test. Interobserver agreement for pulmonary artery and vein assessment was substantial or almost perfect (κ=0.72-0.86). For pulmonary arterial and venous variation assessment, there were no significant differences in sensitivity, specificity, and accuracy among non-contrast-enhanced MRA (pulmonary arteries: sensitivity, 77.1%; specificity, 97.4%; accuracy, 87.7%; pulmonary veins: sensitivity, 50%; specificity, 98.5%; accuracy, 93.2%), 4D contrast-enhanced MRA (pulmonary arteries: sensitivity, 77.1%; specificity, 97.4%; accuracy, 87.7%; pulmonary veins: sensitivity, 62.5%; specificity, 100.0%; accuracy, 95.9%), and thin-section contrast-enhanced MDCT (pulmonary arteries: sensitivity, 91.4%; specificity, 89.5%; accuracy, 90.4%; pulmonary veins: sensitivity, 50%; specificity, 100.0%; accuracy, 95.9%) (p>0.05). Pulmonary vascular assessment of patients with NSCLC before surgical resection by non-contrast-enhanced MRA can be considered equivalent to that by 4D contrast-enhanced MRA and contrast-enhanced MDCT.

Easier to swallow: pictorial review of structural findings of the pharynx at barium pharyngography.

PubMed

Tao, Ting Y; Menias, Christine O; Herman, Thomas E; McAlister, William H; Balfe, Dennis M

2013-01-01

Barium pharyngography remains an important diagnostic tool in the evaluation of patients with dysphagia. Pharyngography can not only help detect functional abnormalities but also help identify a wide spectrum of structural abnormalities in children and adults. These structural abnormalities may reflect malignant or nonmalignant oropharyngeal, hypopharyngeal, or laryngeal processes that deform or alter normal coated mucosal surfaces. Therefore, an understanding of the normal appearance of the pharynx at contrast material-enhanced imaging is necessary for accurate detection and interpretation of abnormal findings. Congenital malformations are more typically identified in the younger population; inflammatory and infiltrative diseases, trauma, foreign bodies, and laryngeal cysts can be seen in all age groups; and Zenker and Killian-Jamieson diverticula tend to occur in the older population. Squamous cell carcinoma is by far the most common malignant process, with contrast-enhanced imaging findings that depend on tumor location and morphology. Treatments of head and neck cancers include total laryngectomy and radiation therapy, both of which alter normal anatomy. Patients are usually evaluated immediately after laryngectomy to detect complications such as fistulas; later, pharyngography is useful for identifying and characterizing strictures. Deviation from the expected posttreatment appearance, such as irregular narrowing or mucosal nodularity, should prompt direct visualization to evaluate for recurrence. Contrast-enhanced imaging of the pharynx is commonly used in patients who present with dysphagia, and radiologists should be familiar with the barium pharyngographic appearance of the normal pharyngeal anatomy and of some of the processes that alter normal anatomy. © RSNA, 2013.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, V.J.; Patz, E.; Harris, P.L.

Pleural abnormalities identified on anatomical studies are often nonspecific and may represent benign or malignant disease. We prospectively evaluated the ability of FDG-PET to identify malignancy in patients with pleural abnormalities detected on chest radiographs or chest CT. Thirty-two patients with pleural abnormalities (pleural masses, thickening or effusions) found on chest radiographs or CT were evaluated by FDG-PET. Regions of interest (ROI) were identified on the PET images correlating to anatomic abnormalities and standard uptake ratios (SUR`s) of these ROI`s were calculated. A SUR value of 2.5 or greater was considered positive for malignancy. Physicians blinded to biopsy results gradedmore » their confidence of malignancy (1-5 scale) and graded lesion FDG uptake with respect to mediastinal radioactivity. Twenty-three of the patients had definitive diagnoses by tissue biopsy. Seventeen of these patients had malignant (SUR=7.9{plus_minus}3.8) and 6 had benign (SUR=2.8{plus_minus}2.4) causes of their pleural abnormalities (p=0.001). All but two malignant cases had SURs higher than 2.5 and one of these two was correctly interpreted by the observers. SURs lower than 2.5 were seen in four of the six (67%) benign pleural abnormalities. Using a combination of both visual and semiquantitative analysis, the sensitivity of FDG-PET for detecting malignant pleural abnormalities was 94%. Active infections in the pleural space had increased FDG uptake on PET studies while other benign pleural abnormalities did not. FDG-PET has very high sensitivity for detecting malignant pleural abnormalities and can differentiate benign from malignant pleural abnormalities.« less

Effect of Neonatal Clomipramine Treatment on Consummatory Successive Negative Contrast

ERIC Educational Resources Information Center

Ruetti, Eliana; Burgueno, Adriana L.; Justel, Nadia R.; Pirola, Carlos J.; Mustaca, Alba E.

2013-01-01

Neonatal administration of clomipramine (CLI) produces physiological, neuroendocrinal and behavioral abnormalities in rats when they reach adulthood, which are similar to those observed in animal models of depression. In consummatory successive negative contrast (cSNC), rats that have had experience drinking 32% sucrose solution drink…

Effect of contrast leakage on the detection of abnormal brain tumor vasculature in high-grade glioma.

PubMed

LaViolette, Peter S; Daun, Mitchell K; Paulson, Eric S; Schmainda, Kathleen M

2014-02-01

Abnormal brain tumor vasculature has recently been highlighted by a dynamic susceptibility contrast (DSC) MRI processing technique. The technique uses independent component analysis (ICA) to separate arterial and venous perfusion. The overlap of the two, i.e. arterio-venous overlap or AVOL, preferentially occurs in brain tumors and predicts response to anti-angiogenic therapy. The effects of contrast agent leakage on the AVOL biomarker have yet to be established. DSC was acquired during two separate contrast boluses in ten patients undergoing clinical imaging for brain tumor diagnosis. Three components were modeled with ICA, which included the arterial and venous components. The percentage of each component as well as a third component were determined within contrast enhancing tumor and compared. AVOL within enhancing tumor was also compared between doses. The percentage of enhancing tumor classified as not arterial or venous and instead into a third component with contrast agent leakage apparent in the time-series was significantly greater for the first contrast dose compared to the second. The amount of AVOL detected within enhancing tumor was also significantly greater with the second dose compared to the first. Contrast leakage results in large signal variance classified as a separate component by the ICA algorithm. The use of a second dose mitigates the effect and allows measurement of AVOL within enhancement.

Longitudinal measurements of luminance and chromatic contrast sensitivity: comparison between wavefront-guided LASIK and contralateral PRK for myopia.

PubMed

Barboni, Mirella Telles Salgueiro; Feitosa-Santana, Claudia; Barreto Junior, Jackson; Lago, Marcos; Bechara, Samir Jacob; Alves, Milton Ruiz; Ventura, Dora Fix

2013-10-01

The present study aimed to compare the postoperative contrast sensitivity functions between wavefront-guided LASIK eyes and their contralateral wavefront-guided PRK eyes. The participants were 11 healthy subjects (mean age=32.4 ± 6.2 years) who had myopic astigmatism. The spatial contrast sensitivity functions were measured before and three times after the surgery. Psycho and a Cambridge graphic board (VSG 2/4) were used to measure luminance, red-green, and blue-yellow spatial contrast sensitivity functions (from 0.85 to 13.1 cycles/degree). Longitudinal analysis and comparison between surgeries were performed. There was no significant contrast sensitivity change during the one-year follow-up measurements neither for LASIK nor for PRK eyes. The comparison between procedures showed no differences at 12 months postoperative. The present data showed similar contrast sensitivities during one-year follow-up of wave-front guided refractive surgeries. Moreover, one year postoperative data showed no differences in the effects of either wavefront-guided LASIK or wavefront-guided PRK on the luminance and chromatic spatial contrast sensitivity functions.

Electroencephalography in the Diagnosis of Genetic Generalized Epilepsy Syndromes

PubMed Central

Seneviratne, Udaya; Cook, Mark J.; D’Souza, Wendyl Jude

2017-01-01

Genetic generalized epilepsy (GGE) consists of several syndromes diagnosed and classified on the basis of clinical features and electroencephalographic (EEG) abnormalities. The main EEG feature of GGE is bilateral, synchronous, symmetric, and generalized spike-wave complex. Other classic EEG abnormalities are polyspikes, epileptiform K-complexes and sleep spindles, polyspike-wave discharges, occipital intermittent rhythmic delta activity, eye-closure sensitivity, fixation-off sensitivity, and photoparoxysmal response. However, admixed with typical changes, atypical epileptiform discharges are also commonly seen in GGE. There are circadian variations of generalized epileptiform discharges. Sleep, sleep deprivation, hyperventilation, intermittent photic stimulation, eye closure, and fixation-off are often used as activation techniques to increase the diagnostic yield of EEG recordings. Reflex seizure-related EEG abnormalities can be elicited by the use of triggers such as cognitive tasks and pattern stimulation during the EEG recording in selected patients. Distinct electrographic abnormalities to help classification can be identified among different electroclinical syndromes. PMID:28993753

Mechanisms and consequences of paternally transmitted chromosomal abnormalities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marchetti, F; Wyrobek, A J

Paternally transmitted chromosomal damage has been associated with pregnancy loss, developmental and morphological defects, infant mortality, infertility, and genetic diseases in the offspring including cancer. There is epidemiological evidence linking paternal exposure to occupational or environmental agents with an increased risk of abnormal reproductive outcomes. There is also a large body of literature on germ cell mutagenesis in rodents showing that treatment of male germ cells with mutagens has dramatic consequences on reproduction producing effects such as those observed in human epidemiological studies. However, we know very little about the etiology, transmission and early embryonic consequences of paternally-derived chromosomal abnormalities.more » The available evidence suggests that: (1) there are distinct patterns of germ cell-stage differences in the sensitivity of induction of transmissible genetic damage with male postmeiotic cells being the most sensitive; (2) cytogenetic abnormalities at first metaphase after fertilization are critical intermediates between paternal exposure and abnormal reproductive outcomes; and, (3) there are maternally susceptibility factors that may have profound effects on the amount of sperm DNA damage that is converted into chromosomal aberrations in the zygote and directly affect the risk for abnormal reproductive outcomes.« less

Gadolinium Deposition in Human Brain Tissues after Contrast-enhanced MR Imaging in Adult Patients without Intracranial Abnormalities.

PubMed

McDonald, Robert J; McDonald, Jennifer S; Kallmes, David F; Jentoft, Mark E; Paolini, Michael A; Murray, David L; Williamson, Eric E; Eckel, Laurence J

2017-11-01

Purpose To determine whether gadolinium deposits in neural tissues of patients with intracranial abnormalities following intravenous gadolinium-based contrast agent (GBCA) exposure might be related to blood-brain barrier integrity by studying adult patients with normal brain pathologic characteristics. Materials and Methods After obtaining antemortem consent and institutional review board approval, the authors compared postmortem neuronal tissue samples from five patients who had undergone four to 18 gadolinium-enhanced magnetic resonance (MR) examinations between 2005 and 2014 (contrast group) with samples from 10 gadolinium-naive patients who had undergone at least one MR examination during their lifetime (control group). All patients in the contrast group had received gadodiamide. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy with energy-dispersive x-ray spectroscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Results Tissues from the four neuroanatomic regions of gadodiamide-exposed patients contained 0.1-19.4 μg of gadolinium per gram of tissue in a statistically significant dose-dependent relationship (globus pallidus: ρ = 0.90, P = .04). In contradistinction, patients in the control group had undetectable levels of gadolinium with ICP-MS. All patients had normal brain pathologic characteristics at autopsy. Three patients in the contrast group had borderline renal function (estimated glomerular filtration rate <45 mL/min/1.73 m 2 ) and hepatobiliary dysfunction at MR examination. Gadolinium deposition in the contrast group was localized to the capillary endothelium and neuronal interstitium and, in two cases, within the nucleus of the cell. Conclusion Gadolinium deposition in neural tissues after GBCA administration occurs in the absence of intracranial abnormalities that might affect the permeability of the blood-brain barrier. These findings challenge current understanding of the biodistribution of these contrast agents and their safety. © RSNA, 2017.

Optimization of fecal cytology in the dog: comparison of three sampling methods.

PubMed

Frezoulis, Petros S; Angelidou, Elisavet; Diakou, Anastasia; Rallis, Timoleon S; Mylonakis, Mathios E

2017-09-01

Dry-mount fecal cytology (FC) is a component of the diagnostic evaluation of gastrointestinal diseases. There is limited information on the possible effect of the sampling method on the cytologic findings of healthy dogs or dogs admitted with diarrhea. We aimed to: (1) establish sampling method-specific expected values of selected cytologic parameters (isolated or clustered epithelial cells, neutrophils, lymphocytes, macrophages, spore-forming rods) in clinically healthy dogs; (2) investigate if the detection of cytologic abnormalities differs among methods in dogs admitted with diarrhea; and (3) investigate if there is any association between FC abnormalities and the anatomic origin (small- or large-bowel diarrhea) or the chronicity of diarrhea. Sampling with digital examination (DE), rectal scraping (RS), and rectal lavage (RL) was prospectively assessed in 37 healthy and 34 diarrheic dogs. The median numbers of isolated ( p = 0.000) or clustered ( p = 0.002) epithelial cells, and of lymphocytes ( p = 0.000), differed among the 3 methods in healthy dogs. In the diarrheic dogs, the RL method was the least sensitive in detecting neutrophils, and isolated or clustered epithelial cells. Cytologic abnormalities were not associated with the origin or the chronicity of diarrhea. Sampling methods differed in their sensitivity to detect abnormalities in FC; DE or RS may be of higher sensitivity compared to RL. Anatomic origin or chronicity of diarrhea do not seem to affect the detection of cytologic abnormalities.

Evaluation of ALK gene rearrangement in central nervous system metastases of non-small-cell lung cancer using two-step RT-PCR technique.

PubMed

Nicoś, M; Krawczyk, P; Wojas-Krawczyk, K; Bożyk, A; Jarosz, B; Sawicki, M; Trojanowski, T; Milanowski, J

2017-12-01

RT-PCR technique has showed a promising value as pre-screening method for detection of mRNA containing abnormal ALK sequences, but its sensitivity and specificity is still discussable. Previously, we determined the incidence of ALK rearrangement in CNS metastases of NSCLC using IHC and FISH methods. We evaluated ALK gene rearrangement using two-step RT-PCR method with EML4-ALK Fusion Gene Detection Kit (Entrogen, USA). The studied group included 145 patients (45 females, 100 males) with CNS metastases of NSCLC and was heterogeneous in terms of histology and smoking status. 21% of CNS metastases of NSCLC (30/145) showed presence of mRNA containing abnormal ALK sequences. FISH and IHC tests confirmed the presence of ALK gene rearrangement and expression of ALK abnormal protein in seven patients with positive result of RT-PCR analysis (4.8% of all patients, 20% of RT-PCR positive patients). RT-PCR method compared to FISH analysis achieved 100% of sensitivity and only 82.7% of specificity. IHC method compared to FISH method indicated 100% of sensitivity and 97.8% of specificity. In comparison to IHC, RT-PCR showed identical sensitivity with high number of false positive results. Utility of RT-PCR technique in screening of ALK abnormalities and in qualification patients for molecularly targeted therapies needs further validation.

Reduced Oblique Effect in Children with Autism Spectrum Disorders (ASD)

PubMed Central

Sysoeva, Olga V.; Davletshina, Maria A.; Orekhova, Elena V.; Galuta, Ilia A.; Stroganova, Tatiana A.

2016-01-01

People are very precise in the discrimination of a line orientation relative to the cardinal (vertical and horizontal) axes, while their orientation discrimination sensitivity along the oblique axes is less refined. This difference in discrimination sensitivity along cardinal and oblique axes is called the “oblique effect.” Given that the oblique effect is a basic feature of visual processing with an early developmental origin, its investigation in children with Autism Spectrum Disorder (ASD) may shed light on the nature of visual sensory abnormalities frequently reported in this population. We examined line orientation sensitivity along oblique and vertical axes in a sample of 26 boys with ASD (IQ > 68) and 38 typically developing (TD) boys aged 7–15 years, as well as in a subsample of carefully IQ-matched ASD and TD participants. Children were asked to detect the direction of tilt of a high-contrast black-and-white grating relative to vertical (90°) or oblique (45°) templates. The oblique effect was reduced in children with ASD as compared to TD participants, irrespective of their IQ. This reduction was due to poor orientation sensitivity along the vertical axis in ASD children, while their ability to discriminate line orientation along the oblique axis was unaffected. We speculate that this deficit in sensitivity to vertical orientation may reflect disrupted mechanisms of early experience-dependent learning that takes place during the critical period for orientation selectivity. PMID:26834540

Failure of hippocampal deactivation during loss events in treatment-resistant depression.

PubMed

Johnston, Blair A; Tolomeo, Serenella; Gradin, Victoria; Christmas, David; Matthews, Keith; Steele, J Douglas

2015-09-01

Major depressive disorder is characterized by anhedonia, cognitive biases, ruminations, hopelessness and increased anxiety. Blunted responses to rewards have been reported in a number of recent neuroimaging and behavioural studies of major depressive disorder. In contrast, neural responses to aversive events remain an under-studied area. While selective serotonergic reuptake inhibitors are often effective in treating major depressive disorder, their mechanism of action remains unclear. Following a series of animal model investigations of depressive illness and serotonergic function, Deakin and Graeff predicted that brain activity in patients with major depressive disorder is associated with an overactive dorsal raphe nucleus with overactive projections to the amygdala, periaqueductal grey and striatum, and an underactive median raphe nucleus with underactive projections to the hippocampus. Here we describe an instrumental loss-avoidance and win-gain reinforcement learning functional magnetic resonance imaging study with 40 patients with highly treatment-resistant major depressive disorder and never-depressed controls. The dorsal raphe nucleus/ periaqueductal grey region of the midbrain and hippocampus were found to be overactive in major depressive disorder during unsuccessful loss-avoidance although the median raphe nucleus was not found to be underactive. Hippocampal overactivity was due to a failure to deactivate during loss events in comparison to controls, and hippocampal over-activity correlated with depression severity, self-report 'hopelessness' and anxiety. Deakin and Graeff argued that the median raphe nucleus normally acts to inhibit consolidation of aversive memories via the hippocampus and this system is underactive in major depressive disorder, facilitating the development of ruminations, while the dorsal raphe nucleus system is engaged by distal cues predictive of threats and is overactive in major depressive disorder. During win events the striatum was underactive in major depressive disorder. We tested individual patient consistency of these findings using within-study replication. Abnormal hippocampal activity correctly predicted individual patient diagnostic status in 97% (sensitivity 95%, specificity 100%) of subjects, and abnormal striatal activity predicted diagnostic status in 84% (sensitivity 79%, specificity 89%) of subjects. We conclude that the neuroimaging findings were largely consistent with Deaken and Graeff's predictions, abnormally increased hippocampal activity during loss events was an especially consistent abnormality, and brainstem serotonergic nuclei merit further study in depressive illness. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Defining the neurotoxin derived illness chronic ciguatera using markers of chronic systemic inflammatory disturbances: a case/control study.

PubMed

Shoemaker, Ritchie C; House, Dennis; Ryan, James C

2010-01-01

Ciguatoxins are extremely potent neurotoxins, produced by tropical marine dinoflagellates, that persistently enter into our food web. Over 100,000 people annually experience acute ciguatera poisoning from consuming toxic fish. Roughly 5% of these victims will develop chronic ciguatera (CC), a widespread, multisymptom, multisystem, chronic illness that can last tens of years. CC is marked by disproportionate disability and non-specific refractory symptoms such as fatigue, cognitive deficits and pain, and is suggestive of other illnesses. Its unknown pathophysiology makes both diagnosis and treatment difficult. We wanted to compare objective parameters of visual contrast sensitivity testing, measures of innate immune response and genetic markers in cases to controls to assess the potential for the presence of persistent inflammatory parameters that are demonstrated in other biotoxin associated illnesses at a single specialty clinic. Using 59 CC cases and 59 controls we present in retrospective review, in all cases, abnormalities in immune responses paralleling the chronic systemic inflammatory response syndrome seen in several other chronic diseases. This study defines a preliminary case definition using medical history, total symptoms, visual contrast sensitivity, HLA DR genotype analysis, reduction of regulatory neuropeptides VIP and MSH, and multiple measures of inflammatory immune response, especially C4a and TGFβ1, thereby providing a basis for identification and targeted therapy. CC provides a model for chronic human illness associated with initiation of inflammatory responses by biologically produced neurotoxins. Copyright © 2010 Elsevier Inc. All rights reserved.

Enhanced Detection of Chromosomal Abnormalities in Chronic Lymphocytic Leukemia by Conventional Cytogenetics Using CpG Oligonucleotide in Combination with Pokeweed Mitogen and Phorbol Myristate Acetate

PubMed Central

Muthusamy, Natarajan; Breidenbach, Heather; Andritsos, Leslie; Flynn, Joseph; Jones, Jeffrey; Ramanunni, Asha; Mo, Xiaokui; Jarjoura, David; Byrd, John C.; Heerema, Nyla A.

2011-01-01

Reproducible cytogenetic analysis in CLL has been limited by the inability to obtain reliable metaphase cells for analysis. CpG oligonucleotide and cytokine stimulation have been shown to improve metaphase analysis of CLL cytogenetic abnormalities, but is limited by variability in the cytokine receptor levels, stability and biological activity of the cytokine in culture conditions and high costs associated with these reagents. We report here use of a novel, stable CpG, GNKG168 along with pokeweed mitogen (PWM) and phorbol 12-myristate 13-acetate (PMA) for conventional cytogenetic assessment in CLL. We demonstrate that the combined use of GNKG168+PWM/PMA increased the sensitivity of detection of chromosomal abnormalities compared to PWM/PMA (n=207, odds ratio=2.2, p=0.0002) and GNKG168 (n=219, odds ratio=1.5, p=0.0452). Further, a significant increase in sensitivity to detect complexity ≥3 with GNKG168+PWM/PMA compared to GNKG168 alone (odds ratio 8.0, p=0.0022) or PWM/PMA alone (odds ratio 9.6, p=0.0007) was observed. The trend toward detection of higher complexity was significantly greater with GNKG168+PWM/PMA compared to GNKG168 alone (p=0.0412). The increased sensitivity was mainly attributed to the addition of PWM/PMA with GNKG168 because GNKG168 alone showed no difference in sensitivity for detection of complex abnormalities (p=0.17). Comparison of fluorescence in situ hybridization (FISH) results with karyotypic results showed a high degree of consistency, although some complex karyotypes were present in cases with no adverse FISH abnormality. These studies provide evidence for potential use of GNKG168 in combination with PWM and PMA in karyotypic analysis of CLL patient samples to better identify chromosomal abnormalities for risk stratification. PMID:21494579

Clinical color vision testing and correlation with visual function.

PubMed

Zhao, Jiawei; Davé, Sarita B; Wang, Jiangxia; Subramanian, Prem S

2015-09-01

To determine if Hardy-Rand-Rittler (H-R-R) and Ishihara testing are accurate estimates of color vision in subjects with acquired visual dysfunction. Assessment of diagnostic tools. Twenty-two subjects with optic neuropathy (aged 18-65) and 18 control subjects were recruited prospectively from an outpatient clinic. Individuals with visual acuity (VA) <20/200 or with congenital color blindness were excluded. All subjects underwent a comprehensive eye examination including VA, color vision, and contrast sensitivity testing. Color vision was assessed using H-R-R and Ishihara plates and Farnsworth D-15 (D-15) discs. D-15 is the accepted standard for detecting and classifying color vision deficits. Contrast sensitivity was measured using Pelli-Robson contrast sensitivity charts. No relationship was found between H-R-R and D-15 scores (P = .477). H-R-R score and contrast sensitivity were positively correlated (P = .003). On multivariate analysis, contrast sensitivity (β = 8.61, P < .001) and VA (β = 2.01, P = .022) both showed association with H-R-R scores. Similar to H-R-R, Ishihara score did not correlate with D-15 score (P = .973), but on multivariate analysis was related to contrast sensitivity (β = 8.69, P < .001). H-R-R and Ishihara scores had an equivalent relationship with contrast sensitivity (P = .069). Neither H-R-R nor Ishihara testing appears to assess color identification in patients with optic neuropathy. Both H-R-R and Ishihara testing are correlated with contrast sensitivity, and these tests may be useful clinical surrogates for contrast sensitivity testing. Copyright © 2015 Elsevier Inc. All rights reserved.

Spatial contrast sensitivity at twilight: luminance, monocularity, and oxygenation.

PubMed

Connolly, Desmond M

2010-05-01

Visual performance in dim light is compromised by lack of oxygen (hypoxia). The possible influence of altered oxygenation on foveal contrast sensitivity under mesopic (twilight) viewing conditions is relevant to aircrew flying at night, including when using night vision devices, but is poorly documented. Foveal contrast sensitivity was measured binocularly and monocularly in 12 subjects at 7 spatial frequencies, ranging from 0.5 to approximately 16 cycles per degree, using sinusoidal Gabor patch gratings. Hypoxic performance breathing 14.1% oxygen, equivalent to altitude exposure at 3048 m (10,000 ft), was compared with breathing air at sea level (normoxia) at low photopic (28 cd x m(-2)), borderline upper mesopic (approximately 2.1 cd x m(-2)) and midmesopic (approximately 0.26 cd x m(-2)) luminance. Mesopic performance was also assessed breathing 100% oxygen (hyperoxia). Typical 'inverted U' log/log plots of the contrast sensitivity function were obtained, with elevated thresholds (reduced sensitivity) at lower luminance. Binocular viewing enhanced sensitivity by a factor approximating square root of 2 for most conditions, supporting neural summation of the contrast signal, but had greater influence at the lowest light level and highest spatial frequencies (8.26 and 16.51 cpd). Respiratory challenges had no effect. Contrast sensitivity is poorer when viewing monocularly and especially at midmesopic luminance, with relevance to night flying. The foveal contrast sensitivity function is unaffected by respiratory disturbance when twilight conditions favor cone vision, despite known effects on retinal illumination (pupil size). The resilience of the contrast sensitivity function belies the vulnerability of foveal low contrast acuity to mild hypoxia at mesopic luminance.

Insulin secretion and insulin resistance in Korean women with gestational diabetes mellitus and impaired glucose tolerance.

PubMed

Yang, Sae Jeong; Kim, Tae Nyun; Baik, Sei Hyun; Kim, Tae Sun; Lee, Kwan Woo; Nam, Moonsuk; Park, Yong Soo; Woo, Jeong-Teak; Kim, Young Seol; Kim, Sung-Hoon

2013-05-01

The aim was to compare the insulin sensitivity and secretion index of pregnant Korean women with normal glucose tolerance (NGT), gestational impaired glucose tolerance (GIGT; only one abnormal value according to the Carpenter and Coustan criteria), and gestational diabetes mellitus (GDM). A cross-sectional study was performed with 1,163 pregnant women with positive (1-hour plasma glucose ≥ 7.2 mmol/L) in a 50-g oral glucose challenge test (OGCT). The 100-g oral glucose tolerance test (OGTT) was used to stratify the participants into three groups: NGT (n = 588), GIGT (n = 294), and GDM (n = 281). The GDM group had higher homeostasis model assessment of insulin resistance and lower insulin sensitivity index (ISOGTT), quantitative insulin sensitivity check index, homeostasis model assessment for estimation of index β-cell secretion (HOMA-B), first and second phase insulin secretion, and insulin secretion-sensitivity index (ISSI) than the NGT group (p ≤ 0.001 for all). Moreover, the GIGT group had lower ISOGTT, HOMA-B, first and second phase insulin secretion, and ISSI than the NGT group (p < 0.001 for all). Among the GIGT subjects, the 1-hour plasma glucose abnormal levels group showed significantly greater weight gain during pregnancy and higher values in the 50-g OGCT than the other two groups. Moreover, the 1-hour and 2-hour abnormal levels groups had poorer insulin secretion status than the 3-hour abnormal levels group. Korean women with GDM show impairments of both insulin secretion and insulin sensitivity. In addition, GIGT is associated with both β-cell dysfunction and insulin resistance.

Three-dimensional sampling perfection with application-optimised contrasts using a different flip angle evolutions sequence for routine imaging of the spine: preliminary experience

PubMed Central

Tins, B; Cassar-Pullicino, V; Haddaway, M; Nachtrab, U

2012-01-01

Objectives The bulk of spinal imaging is still performed with conventional two-dimensional sequences. This study assesses the suitability of three-dimensional sampling perfection with application-optimised contrasts using a different flip angle evolutions (SPACE) sequence for routine spinal imaging. Methods 62 MRI examinations of the spine were evaluated by 2 examiners in consensus for the depiction of anatomy and presence of artefact. We noted pathologies that might be missed using the SPACE sequence only or the SPACE and a sagittal T1 weighted sequence. The reference standards were sagittal and axial T1 weighted and T2 weighted sequences. At a later date the evaluation was repeated by one of the original examiners and an additional examiner. Results There was good agreement of the single evaluations and consensus evaluation for the conventional sequences: κ>0.8, confidence interval (CI)>0.6–1.0. For the SPACE sequence, depiction of anatomy was very good for 84% of cases, with high interobserver agreement, but there was poor interobserver agreement for other cases. For artefact assessment of SPACE, κ=0.92, CI=0.92–1.0. The SPACE sequence was superior to conventional sequences for depiction of anatomy and artefact resistance. The SPACE sequence occasionally missed bone marrow oedema. In conjunction with sagittal T1 weighted sequences, no abnormality was missed. The isotropic SPACE sequence was superior to conventional sequences in imaging difficult anatomy such as in scoliosis and spondylolysis. Conclusion The SPACE sequence allows excellent assessment of anatomy owing to high spatial resolution and resistance to artefact. The sensitivity for bone marrow abnormalities is limited. PMID:22374284

Three-dimensional sampling perfection with application-optimised contrasts using a different flip angle evolutions sequence for routine imaging of the spine: preliminary experience.

PubMed

Tins, B; Cassar-Pullicino, V; Haddaway, M; Nachtrab, U

2012-08-01

The bulk of spinal imaging is still performed with conventional two-dimensional sequences. This study assesses the suitability of three-dimensional sampling perfection with application-optimised contrasts using a different flip angle evolutions (SPACE) sequence for routine spinal imaging. 62 MRI examinations of the spine were evaluated by 2 examiners in consensus for the depiction of anatomy and presence of artefact. We noted pathologies that might be missed using the SPACE sequence only or the SPACE and a sagittal T(1) weighted sequence. The reference standards were sagittal and axial T(1) weighted and T(2) weighted sequences. At a later date the evaluation was repeated by one of the original examiners and an additional examiner. There was good agreement of the single evaluations and consensus evaluation for the conventional sequences: κ>0.8, confidence interval (CI)>0.6-1.0. For the SPACE sequence, depiction of anatomy was very good for 84% of cases, with high interobserver agreement, but there was poor interobserver agreement for other cases. For artefact assessment of SPACE, κ=0.92, CI=0.92-1.0. The SPACE sequence was superior to conventional sequences for depiction of anatomy and artefact resistance. The SPACE sequence occasionally missed bone marrow oedema. In conjunction with sagittal T(1) weighted sequences, no abnormality was missed. The isotropic SPACE sequence was superior to conventional sequences in imaging difficult anatomy such as in scoliosis and spondylolysis. The SPACE sequence allows excellent assessment of anatomy owing to high spatial resolution and resistance to artefact. The sensitivity for bone marrow abnormalities is limited.

Clinical Utility and Lifespan Profiling of Neurological Soft Signs in Schizophrenia Spectrum Disorders.

PubMed

Chan, Raymond C K; Xie, Weizhen; Geng, Fu-lei; Wang, Ya; Lui, Simon S Y; Wang, Chuan-yue; Yu, Xin; Cheung, Eric F C; Rosenthal, Robert

2016-05-01

Neurological soft signs (NSSs) bear the promise for early detection of schizophrenia spectrum disorders. Nonetheless, the sensitivity and specificity of NSSs in the psychosis continuum remains a topic of controversy. It is also unknown how NSSs reveal neurodevelopmental abnormality in schizophrenia. We investigated the effect sizes of NSSs in differentiating individuals with schizophrenia spectrum disorders from individuals with other psychiatric conditions and from covariate-matched healthy subjects. We also investigated the partitioned age-related variations of NSSs in both schizophrenia and healthy individuals. NSSs were assessed by the abridged version of the Cambridge Neurological Inventory (CNI) in 3105 participants, consisting of healthy individuals (n=1577), unaffected first-degree relatives of schizophrenia patients (n= 155), individuals with schizotypal personality disorder (n= 256), schizophrenia patients (n= 738), and other psychiatric patients (n= 379). Exact matching and propensity score matching procedures were performed to control for covariates. Multiple regression was used to partition age-related variations. Individuals along the schizophrenia continuum showed elevated levels of NSSs, with moderate effect sizes, in contrast to other psychiatric patients who had minimal NSSs, as well as matched healthy controls. Furthermore, the age-and-NSS relationship in schizophrenia patients was represented by a flat but overall elevated pattern, in contrast to a U-shaped pattern in healthy individuals. In sum, NSSs capture a moderate portion of psychosis proneness with reasonable specificity. Lifespan profiling reveals an abnormal developmental trajectory of NSSs in schizophrenia patients, which supports the endophenotype hypothesis of NSSs by associating it with the neurodevelopmental model of schizophrenia. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A Normative Data Set for the Clinical Assessment of Achromatic and Chromatic Contrast Sensitivity Using a qCSF Approach.

PubMed

Kim, Yeon Jin; Reynaud, Alexandre; Hess, Robert F; Mullen, Kathy T

2017-07-01

The measurement of achromatic sensitivity has been an important tool for monitoring subtle changes in vision as the result of disease or response to therapy. In this study, we aimed to provide a normative data set for achromatic and chromatic contrast sensitivity functions within a common cone contrast space using an abbreviated measurement approach suitable for clinical practice. In addition, we aimed to provide comparisons of achromatic and chromatic binocular summation across spatial frequency. We estimated monocular cone contrast sensitivity functions (CCSFs) using a quick Contrast Sensitivity Function (qCSF) approach for achromatic as well as isoluminant, L/M cone opponent, and S cone opponent stimuli in a healthy population of 51 subjects. We determined the binocular CCSFs for achromatic and chromatic vision to evaluate the degree of binocular summation across spatial frequency for these three different mechanisms in a subset of 20 subjects. Each data set shows consistent contrast sensitivity across the population. They highlight the extremely high cone contrast sensitivity of L/M cone opponency compared with the S-cone and achromatic responses. We also find that the two chromatic sensitivities are correlated across the healthy population. In addition, binocular summation for all mechanisms depends strongly on stimulus spatial frequency. This study, using an approach well suited to the clinic, is the first to provide a comparative normative data set for the chromatic and achromatic contrast sensitivity functions, yielding quantitative comparisons of achromatic, L/M cone opponent, and S cone opponent chromatic sensitivities as a function of spatial frequency.

Improved detection rate of cytogenetic abnormalities in chronic lymphocytic leukemia and other mature B-cell neoplasms with use of CpG-oligonucleotide DSP30 and interleukin 2 stimulation.

PubMed

Shi, Min; Cipollini, Matthew J; Crowley-Bish, Patricia A; Higgins, Anne W; Yu, Hongbo; Miron, Patricia M

2013-05-01

Detection of cytogenetic abnormalities requires successful culture of the clonal population to obtain metaphase chromosomes for study, and as such, has been hampered by low mitotic indices of mature B cells in culture. Our study presents data on the improved abnormality detection rate with the use of a CpG-oligonucleotide/interleukin 2 (OL/IL-2) culture protocol for mature B-cell neoplasms, including chronic lymphocytic leukemia (CLL) and non-CLL specimens. The increased detection rate of abnormalities, compared with unstimulated culture and traditional pokeweed mitogen culture, was statistically significant for both CLL and non-CLL neoplasms. For CLL specimens, our data also showed that for cytogenetically visible aberrations, OL/IL-2 was as, if not more, sensitive than detection with interphase fluorescence in situ hybridization (iFISH). Use of OL/IL-2 allowed a number of abnormalities to be detected, which were not covered by specific iFISH panels, especially balanced translocations. Therefore, OL/IL-2 stimulation improves diagnostic sensitivity and increases discovery rate of novel prognostic findings.

Rapid Point-Of-Care Breath Test for Biomarkers of Breast Cancer and Abnormal Mammograms

PubMed Central

Phillips, Michael; Beatty, J. David; Cataneo, Renee N.; Huston, Jan; Kaplan, Peter D.; Lalisang, Roy I.; Lambin, Philippe; Lobbes, Marc B. I.; Mundada, Mayur; Pappas, Nadine; Patel, Urvish

2014-01-01

Background Previous studies have reported volatile organic compounds (VOCs) in breath as biomarkers of breast cancer and abnormal mammograms, apparently resulting from increased oxidative stress and cytochrome p450 induction. We evaluated a six-minute point-of-care breath test for VOC biomarkers in women screened for breast cancer at centers in the USA and the Netherlands. Methods 244 women had a screening mammogram (93/37 normal/abnormal) or a breast biopsy (cancer/no cancer 35/79). A mobile point-of-care system collected and concentrated breath and air VOCs for analysis with gas chromatography and surface acoustic wave detection. Chromatograms were segmented into a time series of alveolar gradients (breath minus room air). Segmental alveolar gradients were ranked as candidate biomarkers by C-statistic value (area under curve [AUC] of receiver operating characteristic [ROC] curve). Multivariate predictive algorithms were constructed employing significant biomarkers identified with multiple Monte Carlo simulations and cross validated with a leave-one-out (LOO) procedure. Results Performance of breath biomarker algorithms was determined in three groups: breast cancer on biopsy versus normal screening mammograms (81.8% sensitivity, 70.0% specificity, accuracy 79% (73% on LOO) [C-statistic value], negative predictive value 99.9%); normal versus abnormal screening mammograms (86.5% sensitivity, 66.7% specificity, accuracy 83%, 62% on LOO); and cancer versus no cancer on breast biopsy (75.8% sensitivity, 74.0% specificity, accuracy 78%, 67% on LOO). Conclusions A pilot study of a six-minute point-of-care breath test for volatile biomarkers accurately identified women with breast cancer and with abnormal mammograms. Breath testing could potentially reduce the number of needless mammograms without loss of diagnostic sensitivity. PMID:24599224

EEG, evoked potentials and pulsed Doppler in asphyxiated term infants.

PubMed

Julkunen, Mia K; Himanen, Sari-Leena; Eriksson, Kai; Janas, Martti; Luukkaala, Tiina; Tammela, Outi

2014-09-01

To evaluate electroencephalograms (EEG), evoked potentials (EPs) and Doppler findings in the cerebral arteries as predictors of a 1-year outcome in asphyxiated newborn infants. EEG and EPs (brain stem auditory (BAEP), somatosensory (SEP), visual (VEP) evoked potentials) were assessed in 30 asphyxiated and 30 healthy term infants during the first days (range 1-8). Cerebral blood flow velocities (CBFV) were measured from the cerebral arteries using pulsed Doppler at ∼24h of age. EEG, EPs, Doppler findings, symptoms of hypoxic ischemic encephalopathy (HIE) and their combination were evaluated in predicting a 1-year outcome. An abnormal EEG background predicted poor outcome in the asphyxia group with a sensitivity of 67% and 81% specificity, and an abnormal SEP with 75% and 79%, respectively. Combining increased systolic CBFV (mean+3SD) with abnormal EEG or SEP improved the specificity, but not the sensitivity. The predictive values of abnormal BAEP and VEP were poor. Normal EEG and SEP predicted good outcome in the asphyxia group with sensitivities from 79% to 81%. The combination of normal EEG, normal SEP and systolic CBFV<3SD predicted good outcome with a sensitivity of 74% and 100% specificity. Combining abnormal EEG or EPs findings with increased systolic CBFV did not improve prediction of a poor 1-year outcome of asphyxiated infants. Normal EEG and normal SEP combined with systolic CBFV<3SD at about 24 h can be valuable in the prediction of normal 1-year outcome. Combining systolic CBFV at 24 h with EEG and SEP examinations can be of use in the prediction of normal 1-year outcome among asphyxiated infants. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

The Frequency and Severity of Magnetic Resonance Imaging Abnormalities in Infants with Mild Neonatal Encephalopathy.

PubMed

Walsh, Brian H; Neil, Jeffrey; Morey, JoAnn; Yang, Edward; Silvera, Michelle V; Inder, Terrie E; Ortinau, Cynthia

2017-08-01

To assess and contrast the incidence and severity of abnormalities on cerebral magnetic resonance imaging (MRI) between infants with mild, moderate, and severe neonatal encephalopathy who received therapeutic hypothermia. This retrospective cohort studied infants with mild, moderate, and severe neonatal encephalopathy who received therapeutic hypothermia at a single tertiary neonatal intensive care unit between 2013 and 2015. Two neuroradiologists masked to the clinical condition evaluated brain MRIs for cerebral injury after therapeutic hypothermia using the Barkovich classification system. Additional abnormalities not included in this classification system were also noted. The rate, pattern, and severity of abnormalities/injury were compared across the grades of neonatal encephalopathy. Eighty-nine infants received therapeutic hypothermia and met study criteria, 48 with mild neonatal encephalopathy, 35 with moderate neonatal encephalopathy, and 6 with severe neonatal encephalopathy. Forty-eight infants (54%) had an abnormality on MRI. There was no difference in the rate of overall MRI abnormalities by grade of neonatal encephalopathy (mild neonatal encephalopathy 54%, moderate neonatal encephalopathy 54%, and severe neonatal encephalopathy 50%; P= .89). Basal ganglia/thalamic injury was more common in those with severe neonatal encephalopathy (mild neonatal encephalopathy 4%, moderate neonatal encephalopathy 9%, severe neonatal encephalopathy 34%; P = .03). In contrast, watershed injury did not differ between neonatal encephalopathy grades (mild neonatal encephalopathy 36%, moderate neonatal encephalopathy 32%, severe neonatal encephalopathy 50%; P = .3). Mild neonatal encephalopathy is commonly associated with MRI abnormalities after therapeutic hypothermia. The grade of neonatal encephalopathy during the first hours of life may not discriminate adequately between infants with and without cerebral injury noted on MRI after therapeutic hypothermia. Copyright © 2017 Elsevier Inc. All rights reserved.

Peripheral resolution and contrast sensitivity: Effects of stimulus drift.

PubMed

Venkataraman, Abinaya Priya; Lewis, Peter; Unsbo, Peter; Lundström, Linda

2017-04-01

Optimal temporal modulation of the stimulus can improve foveal contrast sensitivity. This study evaluates the characteristics of the peripheral spatiotemporal contrast sensitivity function in normal-sighted subjects. The purpose is to identify a temporal modulation that can potentially improve the remaining peripheral visual function in subjects with central visual field loss. High contrast resolution cut-off for grating stimuli with four temporal frequencies (0, 5, 10 and 15Hz drift) was first evaluated in the 10° nasal visual field. Resolution contrast sensitivity for all temporal frequencies was then measured at four spatial frequencies between 0.5 cycles per degree (cpd) and the measured stationary cut-off. All measurements were performed with eccentric optical correction. Similar to foveal vision, peripheral contrast sensitivity is highest for a combination of low spatial frequency and 5-10Hz drift. At higher spatial frequencies, there was a decrease in contrast sensitivity with 15Hz drift. Despite this decrease, the resolution cut-off did not vary largely between the different temporal frequencies tested. Additional measurements of contrast sensitivity at 0.5 cpd and resolution cut-off for stationary (0Hz) and 7.5Hz stimuli performed at 10, 15, 20 and 25° in the nasal visual field also showed the same characteristics across eccentricities. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

CT arthrographic patterns in recurrent glenohumeral instability.

PubMed

Singson, R D; Feldman, F; Bigliani, L

1987-10-01

CT double-contrast arthrograms were performed on 54 shoulders in 53 patients with recurrent dislocation or subluxation to detect responsible underlying bony or soft-tissue abnormalities. Lesions of the anterior labrum in 52 (96%) of 54 cases and of the capsuloligamentous complex in 42 (78%) of 54 cases were the two most common abnormalities. There was no difference in the degree or number of labral lesions between subluxations and dislocations. However, more severe capsular lesions, subscapularis tendon tears, and widened subscapularis bursae were consistently found among patients with dislocations. Subsequent clinical, arthroscopic, and surgical findings showed that the use of CT double-contrast arthrograms resulted in improved definition of the multiple lesions associated with glenohumeral dysfunction.

Effect of anterior capsule contraction on visual function after cataract surgery.

PubMed

Hayashi, Ken; Hayashi, Hideyuki

2007-11-01

To examine the effect of contraction of the anterior capsule opening after cataract surgery on visual acuity and contrast sensitivity. Hayashi Eye Hospital, Fukuoka, Japan. Thirty-two eyes of 32 consecutive patients who showed marked contraction of the anterior capsule opening after implantation of an intraocular lens were recruited. The area of the anterior capsule opening was measured by Scheimpflug videophotography before and after neodymium:YAG (Nd:YAG) laser anterior capsulotomy and was correlated with visual acuity and contrast sensitivity. After Nd:YAG laser anterior capsulotomy, the mean area of the anterior capsule opening increased significantly from 8.2 mm(2) to 18.0 mm(2) (P<.0001). Contrast sensitivity at most visual angles also improved significantly after Nd:YAG anterior capsulotomy, although visual acuity did not. The area of the anterior capsule opening before anterior capsulotomy was correlated significantly with contrast sensitivity but not with visual acuity, whereas there was no correlation between the opening area after anterior capsulotomy and visual acuity or contrast sensitivity. Contraction of the anterior capsule opening after cataract surgery significantly diminished contrast sensitivity in proportion to the opening area but did not markedly worsen visual acuity. Neodymium:YAG laser anterior capsulotomy improved contrast sensitivity.

Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor.

PubMed

Hoi, Pui Man; Hiley, C Robin

2006-03-01

Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2+/-0.2 microM, Rmax=99.1+/-3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3+/-1.6 microM, Rmax=59.2+/-7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50 nM) (EC50=2.1+/-0.2 microM, Rmax=58.4+/-1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 microM for 30 min) shifted the oleamide concentration-response curve approximately 30-fold to the right (n=7; P<0.01). Pertussis toxin (400 ng ml-1 for 2 h) caused a two-fold shift in the response curve (EC50=2.2+/-0.4 microM, Rmax=66.8+/-4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 microM) significantly inhibited relaxation induced by oleamide (EC50=3.5+/-0.3 microM, Rmax=75.1+/-1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 microM), nor the CB2 antagonist, SR144528 (1 microM), had significant effects. O-1918 (10 microM), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KC)) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KC) and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site.

Comparison of isolated-check visual evoked potential and standard automated perimetry in early glaucoma and high-risk ocular hypertension

PubMed Central

Chen, Xiang-Wu; Zhao, Ying-Xi

2017-01-01

AIM To compare the diagnostic performance of isolated-check visual evoked potential (icVEP) and standard automated perimetry (SAP), for evaluating the application values of icVEP in the detection of early glaucoma. METHODS Totally 144 subjects (288 eyes) were enrolled in this study. icVEP testing was performed with the Neucodia visual electrophysiological diagnostic system. A 15% positive-contrast (bright) condition pattern was used in this device to differentiate between glaucoma patients and healthy control subjects. Signal-to-noise ratios (SNR) were derived based on a multivariate statistic. The eyes were judged as abnormal if the test yielded an SNR≤1. SAP testing was performed with the Humphrey Field Analyzer II. The visual fields were deemed as abnormality if the glaucoma hemifield test results outside normal limits; or the pattern standard deviation with P<0.05; or the cluster of three or more non-edge points on the pattern deviation plot in a single hemifield with P<0.05, one of which must have a P<0.01. Disc photographs were graded as either glaucomatous optic neuropathy or normal by two experts who were masked to all other patient information. Moorfields regression analysis (MRA) used as a separate diagnostic classification was performed by Heidelberg retina tomograph (HRT). RESULTS When the disc photograph grader was used as diagnostic standard, the sensitivity for SAP and icVEP was 32.3% and 38.5% respectively and specificity was 82.3% and 77.8% respectively. When the MRA Classifier was used as the diagnostic standard, the sensitivity for SAP and icVEP was 48.6% and 51.4% respectively and specificity was 84.1% and 78.0% respectively. When the combined structural assessment was used as the diagnostic standard, the sensitivity for SAP and icVEP was 59.2% and 53.1% respectively and specificity was 84.2% and 84.6% respectivlely. There was no statistical significance between the sensitivity or specificity of SAP and icVEP, regardless of which diagnostic standard was based on. CONCLUSION The diagnostic performance of icVEP is not better than that of SAP in the detection of early glaucoma. PMID:28503434

Measurement of myocardial perfusion and infarction size using computer-aided diagnosis system for myocardial contrast echocardiography.

PubMed

Du, Guo-Qing; Xue, Jing-Yi; Guo, Yanhui; Chen, Shuang; Du, Pei; Wu, Yan; Wang, Yu-Hang; Zong, Li-Qiu; Tian, Jia-Wei

2015-09-01

Proper evaluation of myocardial microvascular perfusion and assessment of infarct size is critical for clinicians. We have developed a novel computer-aided diagnosis (CAD) approach for myocardial contrast echocardiography (MCE) to measure myocardial perfusion and infarct size. Rabbits underwent 15 min of coronary occlusion followed by reperfusion (group I, n = 15) or 60 min of coronary occlusion followed by reperfusion (group II, n = 15). Myocardial contrast echocardiography was performed before and 7 d after ischemia/reperfusion, and images were analyzed with the CAD system on the basis of eliminating particle swarm optimization clustering analysis. The myocardium was quickly and accurately detected using contrast-enhanced images, myocardial perfusion was quantitatively calibrated and a color-coded map calibrated by contrast intensity and automatically produced by the CAD system was used to outline the infarction region. Calibrated contrast intensity was significantly lower in infarct regions than in non-infarct regions, allowing differentiation of abnormal and normal myocardial perfusion. Receiver operating characteristic curve analysis documented that -54-pixel contrast intensity was an optimal cutoff point for the identification of infarcted myocardium with a sensitivity of 95.45% and specificity of 87.50%. Infarct sizes obtained using myocardial perfusion defect analysis of original contrast images and the contrast intensity-based color-coded map in computerized images were compared with infarct sizes measured using triphenyltetrazolium chloride staining. Use of the proposed CAD approach provided observers with more information. The infarct sizes obtained with myocardial perfusion defect analysis, the contrast intensity-based color-coded map and triphenyltetrazolium chloride staining were 23.72 ± 8.41%, 21.77 ± 7.8% and 18.21 ± 4.40% (% left ventricle) respectively (p > 0.05), indicating that computerized myocardial contrast echocardiography can accurately measure infarct size. On the basis of the results, we believe the CAD method can quickly and automatically measure myocardial perfusion and infarct size and will, it is hoped, be very helpful in clinical therapeutics. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Simultaneous Assessment of Myocardial Perfusion, Wall Motion, and Deformation during Myocardial Contrast Echocardiography: A Feasibility Study.

PubMed

Zoppellaro, Giacomo; Venneri, Lucia; Khattar, Rajdeep S; Li, Wei; Senior, Roxy

2016-06-01

Ultrasound contrast agents may be used for the assessment of regional wall motion and myocardial perfusion, but are generally considered not suitable for deformation analysis. The aim of our study was to assess the feasibility of deformation imaging on contrast-enhanced images using a novel methodology. We prospectively enrolled 40 patients who underwent stress echocardiography with continuous intravenous infusion of SonoVue for the assessment of myocardial perfusion imaging with flash replenishment technique. We compared longitudinal strain (Lε) values, assessed with a vendor-independent software (2D CPA), on 68 resting contrast-enhanced and 68 resting noncontrast recordings. Strain analysis on contrast recordings was evaluated in the first cardiac cycles after the flash. Tracking of contrast images was deemed feasible in all subjects and in all views. Contrast administration improved image quality and increased the number of segments used for deformation analysis. Lε of noncontrast and contrast-enhanced images were statistically different (-18.8 ± 4.5% and -22.8 ± 5.4%, respectively; P < 0.001), but their correlation was good (ICC 0.65, 95%CI 0.42-0.78). Patients with resting wall-motion abnormalities showed lower Lε values on contrast recordings (-18.6 ± 6.0% vs. -24.2 ± 5.5%, respectively; P < 0.01). Intra-operator and inter-operator reproducibility was good for both noncontrast and contrast images with no statistical differences. Our study shows that deformation analysis on postflash contrast-enhanced images is feasible and reproducible. Therefore, it would be possible to perform a simultaneous evaluation of wall-motion abnormalities, volumes, ejection fraction, perfusion defects, and cardiac deformation on the same contrast recording. © 2016, Wiley Periodicals, Inc.

Role of MRI T2-DRIVE in the assessment of pituitary stalk abnormalities without gadolinium in pituitary diseases.

PubMed

Godano, Elisabetta; Morana, Giovanni; Di Iorgi, Natascia; Pistorio, Angela; Allegri, Anna Elsa Maria; Napoli, Flavia; Gastaldi, Roberto; Calcagno, Annalisa; Patti, Giuseppa; Gallizia, Annalisa; Notarnicola, Sara; Giaccardi, Marta; Noli, Serena; Severino, Mariasavina; Tortora, Domenico; Rossi, Andrea; Maghnie, Mohamad

2018-06-01

To investigate the role of T2-DRIVE MRI sequence in the accurate measurement of pituitary stalk (PS) size and the identification of PS abnormalities in patients with hypothalamic-pituitary disorders without the use of gadolinium. This was a retrospective study conducted on 242 patients who underwent MRI due to pituitary dysfunction between 2006 and 2015. Among 135 eligible patients, 102 showed eutopic posterior pituitary (PP) gland and 33 showed 'ectopic' PP (EPP). Two readers independently measured the size of PS in patients with eutopic PP at the proximal, midpoint and distal levels on pre- and post-contrast T1-weighted as well as T2-DRIVE images; PS visibility was assessed on pre-contrast T1 and T2-DRIVE sequences in those with EPP. The length, height, width and volume of the anterior pituitary (AP), PP height and length and PP area were analyzed. Significant agreement between the two readers was obtained for T2-DRIVE PS measurements in patients with 'eutopic' PP; a significant difference was demonstrated between the intraclass correlation coefficient calculated on the T2-DRIVE and the T1-pre- and post-contrast sequences. The percentage of PS identified by T2-DRIVE in EPP patients was 72.7% compared to 30.3% of T1 pre-contrast sequences. A significant association was found between the visibility of PS on T2-DRIVE and the height of AP. T2-DRIVE sequence is extremely precise and reliable for the evaluation of PS size and the recognition of PS abnormalities; the use of gadolinium-based contrast media does not add significant information and may thus be avoided. © 2018 European Society of Endocrinology.

Abnormal gel flotation caused by contrast media during adrenal vein sampling

PubMed Central

Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Gelati, Matteo; Bassi, Antonella; Contro, Alberto; Pizzolo, Francesca; Guidi, Gian Cesare

2016-01-01

Introduction During adrenal venous sampling (AVS) procedure, radiologists administer a contrast agent via the catheter to visualize the proper catheter position. Materials and methods A patient with primary aldosteronism diagnostic-hypothesis was admitted for AVS. A venogram was performed to
confirm the catheter’s position with 2mL of Iopamidol 300 mg/mL. Samples were collected with syringe connected to a hydrophilic coated catheter by low-pressure aspiration from each of the four collection sites: inferior vena cava in the suprarenal portion, inferior vena cava in the infrarenal portion, left adrenal vein, and right adrenal vein; then immediately transferred from syringe to tubes with gel separator. All tubes were centrifuged at 1200 x g for 10 minutes. Results At the end of centrifugation process, primary blood tubes containing blood from inferior vena cava and left adrenal vein exhibited the standard gel separator barrier, while tubes from right adrenal vein showed abnormal flotation of gel separator. The radiologist confirmed the usage of 2.6 mL instead of 2.0 mL of Iopamidol 300 mg/mL. This iodinated contrast media, with 1.33 g/cm3 of density, was used close to the right adrenal vein due to some difficulty to access it. Conclusion The abnormal flotation of gel separator in samples taken from right adrenal vein can be explained by the usage of the iodinated
contrast media. We suggest using plain-tubes (without gel separator) for AVS in order to avoid preanalytical nonconformities. Moreover, a blood volume equivalent to twice the catheter extension should be discarded to eliminate residual contrast media before collection of samples for laboratory assays. PMID:27812311

Characterization of tumor microvascular structure and permeability: comparison between magnetic resonance imaging and intravital confocal imaging

NASA Astrophysics Data System (ADS)

Reitan, Nina Kristine; Thuen, Marte; Goa, Pa˚L. Erik; de Lange Davies, Catharina

2010-05-01

Solid tumors are characterized by abnormal blood vessel organization, structure, and function. These abnormalities give rise to enhanced vascular permeability and may predict therapeutic responses. The permeability and architecture of the microvasculature in human osteosarcoma tumors growing in dorsal window chambers in athymic mice were measured by confocal laser scanning microscopy (CLSM) and dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). Dextran (40 kDa) and Gadomer were used as molecular tracers for CLSM and DCE-MRI, respectively. A significant correlation was found between permeability indicators. The extravasation rate Ki as measured by CLSM correlated positively with DCE-MRI parameters, such as the volume transfer constant Ktrans and the initial slope of the contrast agent concentration-time curve. This demonstrates that these two techniques give complementary information. Extravasation was further related to microvascular structure and was found to correlate with the fractal dimension and vascular density. The structural parameter values that were obtained from CLSM images were higher for abnormal tumor vasculature than for normal vessels.

Ultrasound and computed tomography of the iliosacral lymphatic centre in dogs with anal sac gland carcinoma.

PubMed

Pollard, R E; Fuller, M C; Steffey, M A

2017-06-01

In this prospective study, we hypothesized that computed tomography (CT) would identify more normal and abnormal iliosacral lymph nodes (LNs) than abdominal ultrasound in dogs with anal sac gland carcinoma (ASGC). Twelve client-owned dogs with ASGC but without distant metastasis were enrolled. Abdominal ultrasound and contrast-enhanced CT scans of the abdomen were obtained. Iliosacral LNs were counted and assessed for location, laterality and size. Significantly (P < 0.00001) more iliosacral LNs were identified with CT (61) than ultrasound (30), including significantly (P = 0.00012) more medial iliac LNs with CT (33) than ultrasound (19). There was no difference in number of internal iliac LNs identified with CT versus ultrasound. Significantly (P = 0.000061) more sacral LNs were identified with CT (15) than ultrasound (0). Ultrasound identified slightly more (7) abnormal iliosacral LNs than CT (5). Contrast CT was able to identify more normal but not more abnormal LNs than ultrasound. © 2015 John Wiley & Sons Ltd.

Exogenous attention enhances 2nd-order contrast sensitivity

PubMed Central

Barbot, Antoine; Landy, Michael S.; Carrasco, Marisa

2011-01-01

Natural scenes contain a rich variety of contours that the visual system extracts to segregrate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However, humans are also sensitive to 2nd-order patterns such as spatial variations of texture, which are predominant in natural scenes and cannot be detected by linear mechanisms. We assess whether and how exogenous attention—the involuntary and transient capture of spatial attention—affects the contrast sensitivity of channels sensitive to 2nd-order, texture-defined patterns. Using 2nd-order, texture-defined stimuli, we demonstrate that exogenous attention increases 2nd-order contrast sensitivity at the attended location, while decreasing it at unattended locations, relative to a neutral condition. By manipulating both 1st- and 2nd-order spatial frequency, we find that the effects of attention depend both on 2nd-order spatial frequency of the stimulus and the observer’s 2nd-order spatial resolution at the target location. At parafoveal locations, attention enhances 2nd-order contrast sensitivity to high, but not to low 2nd-order spatial frequencies; at peripheral locations attention also enhances sensitivity to low 2nd-order spatial frequencies. Control experiments rule out the possibility that these effects might be due to an increase in contrast sensitivity at the 1st-order stage of visual processing. Thus, exogenous attention affects 2nd-order contrast sensitivity at both attended and unattended locations. PMID:21356228

Coregistered FDG PET/CT-based textural characterization of head and neck cancer for radiation treatment planning.

PubMed

Yu, Huan; Caldwell, Curtis; Mah, Katherine; Mozeg, Daniel

2009-03-01

Coregistered fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has shown potential to improve the accuracy of radiation targeting of head and neck cancer (HNC) when compared to the use of CT simulation alone. The objective of this study was to identify textural features useful in distinguishing tumor from normal tissue in head and neck via quantitative texture analysis of coregistered 18F-FDG PET and CT images. Abnormal and typical normal tissues were manually segmented from PET/CT images of 20 patients with HNC and 20 patients with lung cancer. Texture features including some derived from spatial grey-level dependence matrices (SGLDM) and neighborhood gray-tone-difference matrices (NGTDM) were selected for characterization of these segmented regions of interest (ROIs). Both K nearest neighbors (KNNs) and decision tree (DT)-based KNN classifiers were employed to discriminate images of abnormal and normal tissues. The area under the curve (AZ) of receiver operating characteristics (ROC) was used to evaluate the discrimination performance of features in comparison to an expert observer. The leave-one-out and bootstrap techniques were used to validate the results. The AZ of DT-based KNN classifier was 0.95. Sensitivity and specificity for normal and abnormal tissue classification were 89% and 99%, respectively. In summary, NGTDM features such as PET Coarseness, PET Contrast, and CT Coarseness extracted from FDG PET/CT images provided good discrimination performance. The clinical use of such features may lead to improvement in the accuracy of radiation targeting of HNC.

Visual impairment evaluation in 119 children with congenital Zika syndrome.

PubMed

Ventura, Liana O; Ventura, Camila V; Dias, Natália de C; Vilar, Isabelle G; Gois, Adriana L; Arantes, Tiago E; Fernandes, Luciene C; Chiang, Michael F; Miller, Marilyn T; Lawrence, Linda

2018-06-01

To assess visual impairment in a large sample of infants with congenital Zika syndrome (CZS) and to compare with a control group using the same assessment protocol. The study group was composed of infants with confirmed diagnosis of CZS. Controls were healthy infants matched for age, sex, and socioeconomic status. All infants underwent comprehensive ophthalmologic evaluation including visual acuity, visual function assessment, and visual developmental milestones. The CZS group included 119 infants; the control group, 85 infants. At examination, the mean age of the CZS group was 8.5 ± 1.2 months (range, 6-13 months); of the controls, 8.4 ± 1.8 months (range, 5-12 months; P = 0.598). Binocular Teller Acuity Card (TAC) testing was abnormal in 107 CZS infants and in 4 controls (89.9% versus 5% [P < 0.001]). In the study group, abnormal monocular TAC results were more frequent in eyes with funduscopic alterations (P = 0.008); however, 104 of 123 structurally normal eyes (84.6%) also presented abnormal TAC results. Binocular contrast sensitivity was reduced in 87 of 107 CZS infants and in 8 of 80 controls (81.3% versus 10% [P < 0.001]). The visual development milestones were less achieved by infants with CZS compared to controls (P < 0.001). Infants with CZS present with severe visual impairment. A protocol for assessment of the ocular findings, visual acuity, and visual developmental milestones tested against age-matched controls is suggested. Copyright © 2018 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Systemic mastocytosis in adults: 2013 update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2013-07-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extracutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The 2008 World Health Organization (WHO) classification of SM has been shown to be prognostically relevant. Classification of SM patients into indolent (SM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD) and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (±corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting. Dasatinib's in vitro anti- KITD816V activity has not translated into significant therapeutic activity in most SM patients. In contrast, recently updated data confirms Midostaurin's significant anti-MC activity in patients with advanced SM. Copyright © 2013 Wiley Periodicals, Inc.

Systemic mastocytosis in adults: 2012 Update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2012-04-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extra-cutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The prognostic relevance of the 2008 World Health Organization (WHO) classification of SM has recently been confirmed. Classification of SM patients into indolent (SM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD) and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (±corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting. Dasatinib's in vitro anti-KITD816V activity has not translated into significant therapeutic activity in most SM patients. In contrast, preliminary data suggest that Midostaurin may produce significant decreases in MC burden in some patients. Copyright © 2012 Wiley Periodicals, Inc.

Systemic mastocytosis in adults: 2011 update on diagnosis, risk stratification, and management.

PubMed

Pardanani, Animesh

2011-04-01

Systemic mastocytosis (SM) results from a clonal proliferation of abnormal mast cells (MC) in one or more extracutaneous organs. The major criterion is presence of multifocal clusters of morphologically abnormal MC in the bone marrow. Minor diagnostic criteria include elevated serum tryptase level, abnormal MC expression of CD25 and/or CD2, and presence of KITD816V. The prognostic relevance of the 2008 World Health Organization (WHO) classification of SM has recently been confirmed. Classification of SM patients into indolent (SM), aggressive SM (ASM), SM associated with a clonal non-MC lineage disease (SM-AHNMD), and mast cell leukemia (MCL) subgroups is a useful first step in establishing prognosis. SM treatment is generally palliative. ISM patients have a normal life expectancy and receive symptom-directed therapy; infrequently, cytoreductive therapy may be indicated for refractory symptoms. ASM patients have disease-related organ dysfunction; interferon-α (±corticosteroids) can control dermatological, hematological, gastrointestinal, skeletal, and mediator-release symptoms, but is hampered by poor tolerability. Similarly, cladribine has broad therapeutic activity, with particular utility when rapid MC debulking is indicated; the main toxicity is myelosuppression. Imatinib has a therapeutic role in the presence of an imatinib-sensitive KIT mutation or in KITD816-unmutated patients. Treatment of SM-AHNMD is governed primarily by the non-MC neoplasm; hydroxyurea has modest utility in this setting. Dasatinib's in vitro anti- KITD816V activity has not translated into significant therapeutic activity in most SM patients. In contrast, preliminary data suggest that Midostaurin may produce significant decreases in MC burden in some patients. Copyright © 2011 Wiley-Liss, Inc.

A model for hormonal control of the menstrual cycle: structural consistency but sensitivity with regard to data.

PubMed

Selgrade, J F; Harris, L A; Pasteur, R D

2009-10-21

This study presents a 13-dimensional system of delayed differential equations which predicts serum concentrations of five hormones important for regulation of the menstrual cycle. Parameters for the system are fit to two different data sets for normally cycling women. For these best fit parameter sets, model simulations agree well with the two different data sets but one model also has an abnormal stable periodic solution, which may represent polycystic ovarian syndrome. This abnormal cycle occurs for the model in which the normal cycle has estradiol levels at the high end of the normal range. Differences in model behavior are explained by studying hysteresis curves in bifurcation diagrams with respect to sensitive model parameters. For instance, one sensitive parameter is indicative of the estradiol concentration that promotes pituitary synthesis of a large amount of luteinizing hormone, which is required for ovulation. Also, it is observed that models with greater early follicular growth rates may have a greater risk of cycling abnormally.

Multifaceted impairments in impulsivity and brain structural abnormalities in opioid dependence and abstinence.

PubMed

Tolomeo, S; Gray, S; Matthews, K; Steele, J D; Baldacchino, A

2016-10-01

Chronic opioid exposure, as a treatment for a variety of disorders or as drug of misuse, is common worldwide, but behavioural and brain abnormalities remain under-investigated. Only a small percentage of patients who receive methadone maintenance treatment (MMT) for previous heroin misuse eventually achieve abstinence and studies on such patients are rare. The Cambridge Neuropsychological Test Automated Battery and T1 weighted magnetic resonance imaging (MRI) were used to study a cohort of 122 male individuals: a clinically stable opioid-dependent patient group receiving MMT (n = 48), an abstinent previously MMT maintained group (ABS) (n = 24) and healthy controls (n = 50). Stable MMT participants deliberated longer and placed higher bets earlier in the Cambridge Gambling Task (CGT) and showed impaired strategic planning compared with healthy controls. In contrast, ABS participants showed impairment in choosing the least likely outcome, delay aversion and risk adjustment on the CGT, and exhibited non-planning impulsivity compared with controls. MMT patients had widespread grey matter reductions in the orbitomedial prefrontal cortex, caudate, putamen and globus pallidus. In contrast, ABS participants showed midbrain-thalamic grey matter reductions. A higher methadone dose at the time of scanning was associated with a smaller globus pallidus in the MMT group. Our findings support an interpretation of heightened impulsivity in patients receiving MMT. Widespread structural brain abnormalities in the MMT group and reduced brain structural abnormality with abstinence suggest benefit of cessation of methadone intake. We suggest that a longitudinal study is required to determine whether abstinence improves abnormalities, or patients who achieve abstinence have reduced abnormalities before methadone cessation.

Cerebral Hemodynamics in Patients with Hemolytic Uremic Syndrome Assessed by Susceptibility Weighted Imaging and Four-Dimensional Non-Contrast MR Angiography.

PubMed

Löbel, Ulrike; Forkert, Nils Daniel; Schmitt, Peter; Dohrmann, Thorsten; Schroeder, Maria; Magnus, Tim; Kluge, Stefan; Weiler-Normann, Christina; Bi, Xiaoming; Fiehler, Jens; Sedlacik, Jan

2016-01-01

Conventional magnetic resonance imaging (MRI) of patients with hemolytic uremic syndrome (HUS) and neurological symptoms performed during an epidemic outbreak of Escherichia coli O104:H4 in Northern Europe has previously shown pathological changes in only approximately 50% of patients. In contrast, susceptibility-weighted imaging (SWI) revealed a loss of venous contrast in a large number of patients. We hypothesized that this observation may be due to an increase in cerebral blood flow (CBF) and aimed to identify a plausible cause. Baseline 1.5T MRI scans of 36 patients (female, 26; male, 10; mean age, 38.2±19.3 years) were evaluated. Venous contrast was rated on standard SWI minimum intensity projections. A prototype four-dimensional (time resolved) magnetic resonance angiography (4D MRA) assessed cerebral hemodynamics by global time-to-peak (TTP), as a surrogate marker for CBF. Clinical parameters studied were hemoglobin, hematocrit, creatinine, urea levels, blood pressure, heart rate, and end-tidal CO2. SWI venous contrast was abnormally low in 33 of 36 patients. TTP ranged from 3.7 to 10.2 frames (mean, 7.9 ± 1.4). Hemoglobin at the time of MRI (n = 35) was decreased in all patients (range, 5.0 to 12.6 g/dL; mean, 8.2 ± 1.4); hematocrit (n = 33) was abnormally low in all but a single patient (range, 14.3 to 37.2%; mean, 23.7 ± 4.2). Creatinine was abnormally high in 30 of 36 patients (83%) (range, 0.8 to 9.7; mean, 3.7 ± 2.2). SWI venous contrast correlated significantly with hemoglobin (r = 0.52, P = 0.0015), hematocrit (r = 0.65, P < 0.001), and TTP (r = 0.35, P = 0.036). No correlation of SWI with blood pressure, heart rate, end-tidal CO2, creatinine, and urea level was observed. Findings suggest that the loss of venous contrast is related to an increase in CBF secondary to severe anemia related to HUS. SWI contrast of patients with pathological conventional MRI findings was significantly lower compared to patients with normal MRI (mean SWI score, 1.41 and 2.05, respectively; P = 0.04). In patients with abnormal conventional MRI, mean TTP (7.45), mean hemoglobin (7.65), and mean hematocrit (22.0) were lower compared to patients with normal conventional MRI scans (mean TTP = 8.28, mean hemoglobin = 8.63, mean hematocrit = 25.23). In contrast to conventional MRI, almost all patients showed pathological changes in cerebral hemodynamics assessed by SWI and 4D MRA. Loss of venous contrast on SWI is most likely the result of an increase in CBF and may be related to the acute onset of anemia. Future studies will be needed to assess a possible therapeutic effect of blood transfusions in patients with HUS and neurological symptoms.

Cross-Sectional Study of Respiratory Symptoms, Spirometry, and Immunologic Sensitivity in Epoxy Resin Workers.

PubMed

Hines, Stella E; Barker, Elizabeth A; Robinson, Maura; Knight, Vijaya; Gaitens, Joanna; Sills, Michael; Duvall, Kirby; Rose, Cecile S

2015-12-01

An epoxy resin worker developed hypersensitivity pneumonitis requiring lung transplantation and had an abnormal blood lymphocyte proliferation test (LPT) to an epoxy hardener. We assessed the prevalence of symptoms, abnormal spirometry, and abnormal epoxy resin LPT results in epoxy resin workers compared to unexposed workers. Participants completed questionnaires and underwent spirometry. We collected blood for epoxy resin LPT and calculated stimulation indices for five epoxy resin products. We compared 38 exposed to 32 unexposed workers. Higher exposed workers were more likely to report cough (OR 10.86, [1.23-infinity], p = 0.030) or wheeze (OR 4.44, [1.00-22.25], p = 0.049) than unexposed workers, even controlling for smoking. Higher exposed workers were more likely to have abnormal FEV1 than unexposed workers (OR 10.51, [0.86-589.9], p = 0.071), although not statistically significant when adjusted for smoking. There were no differences in proportion of abnormal epoxy resin system LPTs between exposed and unexposed workers. In summary, workers exposed to epoxy resin system chemicals were more likely to report respiratory symptoms and have abnormal FEV1 than unexposed workers. Use of epoxy resin LPT was not helpful as a biomarker of exposure and sensitization. © 2015 Wiley Periodicals, Inc.

Cross‐Sectional Study of Respiratory Symptoms, Spirometry, and Immunologic Sensitivity in Epoxy Resin Workers

PubMed Central

Barker, Elizabeth A.; Robinson, Maura; Knight, Vijaya; Gaitens, Joanna; Sills, Michael; Duvall, Kirby; Rose, Cecile S.

2015-01-01

Abstract Objectives An epoxy resin worker developed hypersensitivity pneumonitis requiring lung transplantation and had an abnormal blood lymphocyte proliferation test (LPT) to an epoxy hardener. We assessed the prevalence of symptoms, abnormal spirometry, and abnormal epoxy resin LPT results in epoxy resin workers compared to unexposed workers. Methods Participants completed questionnaires and underwent spirometry. We collected blood for epoxy resin LPT and calculated stimulation indices for five epoxy resin products. Results We compared 38 exposed to 32 unexposed workers. Higher exposed workers were more likely to report cough (OR 10.86, [1.23‐infinity], p = 0.030) or wheeze (OR 4.44, [1.00‐22.25], p = 0.049) than unexposed workers, even controlling for smoking. Higher exposed workers were more likely to have abnormal FEV1 than unexposed workers (OR 10.51, [0.86‐589.9], p = 0.071), although not statistically significant when adjusted for smoking. There were no differences in proportion of abnormal epoxy resin system LPTs between exposed and unexposed workers. Conclusions In summary, workers exposed to epoxy resin system chemicals were more likely to report respiratory symptoms and have abnormal FEV1 than unexposed workers. Use of epoxy resin LPT was not helpful as a biomarker of exposure and sensitization. PMID:26553118

CT Arthrography and Virtual Arthroscopy in the Diagnosis of the Anterior Cruciate Ligament and Meniscal Abnormalities of the Knee Joint

PubMed Central

Lee, Whal; Kim, Ho Sung; Kim, Seok Jung; Kim, Hyung Ho; Chung, Jin Wook; Kang, Heung Sik; Choi, Ja-Young

2004-01-01

Objective To determine the diagnostic accuracy of CT arthrography and virtual arthroscopy in the diagnosis of anterior cruciate ligament and meniscus pathology. Materials and Methods Thirty-eight consecutive patients who underwent CT arthrography and arthroscopy of the knee were included in this study. The ages of the patients ranged from 19 to 52 years and all of the patients were male. Sagittal, coronal, transverse and oblique coronal multiplanar reconstruction images were reformatted from CT arthrography. Virtual arthroscopy was performed from 6 standard views using a volume rendering technique. Three radiologists analyzed the MPR images and two orthopedic surgeons analyzed the virtual arthroscopic images. Results The sensitivity and specificity of CT arthrography for the diagnosis of anterior cruciate ligament abnormalities were 87.5%-100% and 93.3-96.7%, respectively, and those for meniscus abnormalities were 91.7%-100% and 98.1%, respectively. The sensitivity and specificity of virtual arthroscopy for the diagnosis of anterior cruciate ligament abnormalities were 87.5% and 83.3-90%, respectively, and those for meniscus abnormalities were 83.3%-87.5% and 96.1-98.1%, respectively. Conclusion CT arthrography and virtual arthroscopy showed good diagnostic accuracy for anterior cruciate ligament and meniscal abnormalities. PMID:15064559

Disease spectrum of abnormal serum free light chain ratio and its diagnostic significance

PubMed Central

Xu, Bin; Tang, Yi; Zhou, Jianfeng; Zhang, Peiling; Li, Huijun

2017-01-01

Objective To analyze the spectrum of abnormal serum free light chain ratio (sFLC κ/λ ratio), and to redefine the range of sFLC κ/λ ratio, so as to achieve hierarchical diagnosis of diseases with abnormal sFLC κ/λ ratio, resulting in the increased sensitivity and specificity in the diagnosis of monoclonal plasma diseases. Methods Enrolled 1,340 patients with abnormal sFLC κ/λ ratio (<0.26 or >1.65) were grouped: (1) group A: malignant plasma diseases; (2) group B: monoclonal gammopathies of undetermined significance (MGUS); (3) group C: reactive plasma diseases. These patients were further divided by renal function eGFR <60 or >60 ml/min/1.73m2 to eliminate renal diseases influencing the results. Statistical analyses was performed by using SPSS 22 software. Results When sFLC κ/λ ratio >3.49 and eGFR >60ml/min/1.73m2, the sensitivity and specificity of the diagnosis of malignant plasma diseases were 86.1% and 94.0%, respectively. When sFLC κ/λ ratio >2.89 and eGFR <60ml/min/1.73m2, the sensitivity and specificity of the diagnosis of malignant plasma diseases were 92.0% and 97.0%, respectively. Conclusion The sensitivity and specificity of the diagnosis of monoclonal plasma diseases can be significantly improved by redefining the cut-off value of sFLC κ/λ ratio and the renal function index of eGFR. PMID:29137262

[Early prediction of the neurological result at 12 months in newborns at neurological risk].

PubMed

Herbón, F; Garibotti, G; Moguilevsky, J

2015-08-01

The aim of this study was to evaluate the Amiel-Tison neurological examination (AT) and cranial ultrasound at term for predicting the neurological result at 12 months in newborns with neurological risk. The study included 89 newborns with high risk of neurological damage, who were discharged from the Neonatal Intensive Care of the Hospital Zonal Bariloche, Argentina. The assessment consisted of a neurological examination and cranial ultrasound at term, and neurological examination and evaluation of development at 12 months. The sensitivity, specificity, positive and negative predictor value was calculated. The relationship between perinatal factors and neurodevelopment at 12 month of age was also calculated using logistic regression models. Seventy children completed the follow-up. At 12 months of age, 14% had an abnormal neurological examination, and 17% abnormal development. The neurological examination and the cranial ultrasound at term had low sensitivity to predict abnormal neurodevelopment. At 12 months, 93% of newborns with normal AT showed normal neurological results, and 86% normal development. Among newborns with normal cranial ultrasound the percentages were 90 and 81%, respectively. Among children with three or more perinatal risk factors, the frequency of abnormalities in the neurological response was 5.4 times higher than among those with fewer risk factors, and abnormal development was 3.5 times more frequent. The neurological examination and cranial ultrasound at term had low sensitivity but high negative predictive value for the neurodevelopment at 12 months. Three or more perinatal risk factors were associated with neurodevelopment abnormalities at 12 months of age. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

Screening older cancer patients for a Comprehensive Geriatric Assessment: A comparison of three instruments

PubMed Central

Owusu, Cynthia; Koroukian, Siran M.; Schluchter, Mark; Bakaki, Paul; Berger, Nathan A.

2011-01-01

Background The Vulnerable Elders Survey (VES-13) has been validated for screening older cancer patients for a Comprehensive Geriatric Assessment (CGA). To identify a widely acceptable approach that encourages oncologists to screen older cancer patients for a CGA, we examined the Eastern Cooperative Oncology Group Performance Status (ECOG-PS) and Karnofsky Index of Performance Status (KPS) scales’ ability to identify abnormalities on a CGA and compared the performance of the two instruments with the VES-13. Methods We enrolled 117 participants, ≥65 years with stage I–IV cancer into this cross-sectional study. Our primary outcome variable was ≥two abnormalities on the CGA, (Yes or No). We employed receiver operating characteristic curve analysis to compare the discriminatory abilities of the three instruments to identify ≥two abnormalities on the CGA. Results Of the 117 participants, 43% had ≥two abnormalities on the CGA. The VES-13 was predictive of ≥two abnormalities on the CGA, area under the curve (AUC)=0.85 [(95% CI: 0.78–0.92); sensitivity=88%, specificity=69%, at cut-off ≥3]. The ECOG-PS and KPS showed similar discriminatory powers, AUC=0.88 [(95% CI: 0.83–0.94); sensitivity=94%, specificity=55%, at cut-off ≥1]; and AUC=0.90 [(95% CI: 0.84–0.96); sensitivity=78%, specificity=91%, at cut-off ≤80%], respectively. Conclusion The ECOG-PS and KPS were equivalent to the VES-13 in identifying older cancer patients with at least two abnormalities on the CGA. Given that oncologists are already conversant with the KPS and ECOG-PS, these two instruments offer medical oncologists a widely acceptable approach for screening older patients for a CGA. PMID:21927633

The importance of sensitive screening for abnormal glucose metabolism in patients with IgA nephropathy.

PubMed

Jia, Xiaoyuan; Pan, Xiaoxia; Xie, Jingyuan; Shen, Pingyan; Wang, Zhaohui; Li, Ya; Wang, Weiming; Chen, Nan

2016-01-01

To investigate the prevalence of abnormal glucose metabolism, insulin resistance (IR) and the related risk factors in IgA nephropathy (IgAN) patients. We analyzed oral glucose tolerance test (OGTT) and clinical data of 107 IgAN patients and 106 healthy controls. Glucose metabolism, homeostasis model assessment of insulin resistance (HOMA-IR) and the insulin sensitivity index (ISI) of both groups were evaluated. The prevalence of abnormal glucose metabolism was significantly higher in the IgAN group than in the control group (41.12% vs. 9.43%, p < 0.001), while the prevalence of IR between the two groups was not significantly different. IgAN patients have significantly higher fasting blood glucose, fasting insulin, OGTT 2-hour blood glucose, OGTT 2-hour insulin, HOMA-IR, and lower ISI than healthy controls. Triglyceride (OR = 2.55), 24-hour urine protein excretion (OR = 1.39), and age (OR = 1.06) were independent risk factors for abnormal glucose metabolism in IgAN patients. BMI, eGFR, 24-hour urine protein excretion, triglyceride, fasting blood glucose, fasting insulin, OGTT 2-hour blood glucose, and OGTT 2-hour insulin were significantly higher in IgAN patients with IR than in IgAN patients without IR, while HDL and ISI were significantly lower. BMI, serum albumin, and 24-hour urine protein excretion were correlated factors of IR in IgAN patients. Our study highlighted that abnormal glucose metabolism was common in IgAN patients. Triglyceride and 24-hour urine protein excretion were significant risk factors for abnormal glucose metabolism. Therefore, sensitive screening for glucose metabolism status and timely intervention should be carried out in clinical work.

Abnormal Size-Dependent Modulation of Motion Perception in Children with Autism Spectrum Disorder (ASD).

PubMed

Sysoeva, Olga V; Galuta, Ilia A; Davletshina, Maria S; Orekhova, Elena V; Stroganova, Tatiana A

2017-01-01

Excitation/Inhibition (E/I) imbalance in neural networks is now considered among the core neural underpinnings of autism psychopathology. In motion perception at least two phenomena critically depend on E/I balance in visual cortex: spatial suppression (SS), and spatial facilitation (SF) corresponding to impoverished or improved motion perception with increasing stimuli size, respectively. While SS is dominant at high contrast, SF is evident for low contrast stimuli, due to the prevalence of inhibitory contextual modulations in the former, and excitatory ones in the latter case. Only one previous study (Foss-Feig et al., 2013) investigated SS and SF in Autism Spectrum Disorder (ASD). Our study aimed to replicate previous findings, and to explore the putative contribution of deficient inhibitory influences into an enhanced SF index in ASD-a cornerstone for interpretation proposed by Foss-Feig et al. (2013). The SS and SF were examined in 40 boys with ASD, broad spectrum of intellectual abilities (63 < IQ < 127) and 44 typically developing (TD) boys, aged 6-15 years. The stimuli of small (1°) and large (12°) radius were presented under high (100%) and low (1%) contrast conditions. Social Responsiveness Scale and Sensory Profile Questionnaire were used to assess the autism severity and sensory processing abnormalities. We found that the SS index was atypically reduced, while SF index abnormally enhanced in children with ASD. The presence of abnormally enhanced SF in children with ASD was the only consistent finding between our study and that of Foss-Feig et al. While the SS and SF indexes were strongly interrelated in TD participants, this correlation was absent in their peers with ASD. In addition, the SF index but not the SS index correlated with the severity of autism and the poor registration abilities. The pattern of results is partially consistent with the idea of hypofunctional inhibitory transmission in visual areas in ASD. Nonetheless, the absence of correlation between SF and SS indexes paired with a strong direct link between abnormally enhanced SF and autism symptoms in our ASD sample emphasizes the role of the enhanced excitatory influences by themselves in the observed abnormalities in low-level visual phenomena found in ASD.

Decreased ATP synthesis and lower pH may lead to abnormal muscle contraction and skin sensitivity in human skin.

PubMed

Kim, Eun Ju; Lee, Dong Hun; Kim, Yeon Kyung; Kim, Min-Kyoung; Kim, Jung Yun; Lee, Min Jung; Choi, Won Woo; Eun, Hee Chul; Chung, Jin Ho

2014-12-01

Sensitive skin represents hyperactive sensory symptoms showing exaggerated reactions in response to internal stimulants or external irritants. Although sensitive skin is a very common condition affecting an estimated 50% of the population, its pathophysiology remains largely elusive, particularly with regard to its metabolic aspects. The objective of our study was to investigate the pathogenesis of sensitive skin. We recruited healthy participants with 'sensitive' or 'non-sensitive' skin based on standardized questionnaires and 10% lactic acid stinging test, and obtained skin samples for microarray analysis and subsequent experiments. Microarray transcriptome profiling revealed that genes involved in muscle contraction, carbohydrate and lipid metabolism, and ion transport and balance were significantly decreased in sensitive skin. These altered genes could account for the abnormal muscle contraction, decreased ATP amount in sensitive skin. In addition, pain-related transcripts such as TRPV1, ASIC3 and CGRP were significantly up-regulated in sensitive skin, compared with non-sensitive skin. Our findings suggest that sensitive skin is closely associated with the dysfunction of muscle contraction and metabolic homeostasis. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Contrast Adaptation Implies Two Spatiotemporal Channels but Three Adapting Processes

ERIC Educational Resources Information Center

Langley, Keith; Bex, Peter J.

2007-01-01

The contrast gain control model of adaptation predicts that the effects of contrast adaptation correlate with contrast sensitivity. This article reports that the effects of high contrast spatiotemporal adaptors are maximum when adapting around 19 Hz, which is a factor of two or more greater than the peak in contrast sensitivity. To explain the…

Blood vessel segmentation in color fundus images based on regional and Hessian features.

PubMed

Shah, Syed Ayaz Ali; Tang, Tong Boon; Faye, Ibrahima; Laude, Augustinus

2017-08-01

To propose a new algorithm of blood vessel segmentation based on regional and Hessian features for image analysis in retinal abnormality diagnosis. Firstly, color fundus images from the publicly available database DRIVE were converted from RGB to grayscale. To enhance the contrast of the dark objects (blood vessels) against the background, the dot product of the grayscale image with itself was generated. To rectify the variation in contrast, we used a 5 × 5 window filter on each pixel. Based on 5 regional features, 1 intensity feature and 2 Hessian features per scale using 9 scales, we extracted a total of 24 features. A linear minimum squared error (LMSE) classifier was trained to classify each pixel into a vessel or non-vessel pixel. The DRIVE dataset provided 20 training and 20 test color fundus images. The proposed algorithm achieves a sensitivity of 72.05% with 94.79% accuracy. Our proposed algorithm achieved higher accuracy (0.9206) at the peripapillary region, where the ocular manifestations in the microvasculature due to glaucoma, central retinal vein occlusion, etc. are most obvious. This supports the proposed algorithm as a strong candidate for automated vessel segmentation.

Novel Contrast Mechanisms at 3 Tesla and 7 Tesla

PubMed Central

Regatte, Ravinder R.; Schweitzer, Mark E.

2013-01-01

Osteoarthritis (OA) is the most common musculoskeletal degenerative disease, affecting millions of people. Although OA has been considered primarily a cartilage disorder associated with focal cartilage degeneration, it is accompanied by well-known changes in subchondral and trabecular bone, including sclerosis and osteophyte formation. The exact cause of OA initiation and progression remains under debate, but OA typically first affects weightbearing joints such as the knee. Magnetic resonance imaging (MRI) has been recognized as a potential tool for quantitative assessment of cartilage abnormalities due to its excellent soft tissue contrast. Over the last two decades, several new MR biochemical imaging methods have been developed to characterize the disease process and possibly predict the progression of knee OA. These new MR biochemical methods play an important role not only for diagnosis of disease at an early stage, but also for their potential use in monitoring outcome of various drug therapies (success or failure). Recent advances in multicoil radiofrequency technology and high field systems (3 T and above) significantly improve the sensitivity and specificity of imaging studies for the diagnosis of musculoskeletal disorders. The current state-of-the-art MR imaging methods are briefly reviewed for the quantitative biochemical and functional imaging assessment of musculoskeletal systems. PMID:18850506

Spatial Contrast Sensitivity in Adolescents with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Koh, Hwan Cui; Milne, Elizabeth; Dobkins, Karen

2010-01-01

Adolescents with autism spectrum disorders (ASD) and typically developing (TD) controls underwent a rigorous psychophysical assessment that measured contrast sensitivity to seven spatial frequencies (0.5-20 cycles/degree). A contrast sensitivity function (CSF) was then fitted for each participant, from which four measures were obtained: visual…

Insulin secretion and insulin resistance in Korean women with gestational diabetes mellitus and impaired glucose tolerance

PubMed Central

Yang, Sae Jeong; Kim, Tae Nyun; Baik, Sei Hyun; Kim, Tae Sun; Lee, Kwan Woo; Nam, Moonsuk; Park, Yong Soo; Woo, Jeong-Teak; Kim, Young Seol

2013-01-01

Background/Aims The aim was to compare the insulin sensitivity and secretion index of pregnant Korean women with normal glucose tolerance (NGT), gestational impaired glucose tolerance (GIGT; only one abnormal value according to the Carpenter and Coustan criteria), and gestational diabetes mellitus (GDM). Methods A cross-sectional study was performed with 1,163 pregnant women with positive (1-hour plasma glucose ≥ 7.2 mmol/L) in a 50-g oral glucose challenge test (OGCT). The 100-g oral glucose tolerance test (OGTT) was used to stratify the participants into three groups: NGT (n = 588), GIGT (n = 294), and GDM (n = 281). Results The GDM group had higher homeostasis model assessment of insulin resistance and lower insulin sensitivity index (ISOGTT), quantitative insulin sensitivity check index, homeostasis model assessment for estimation of index β-cell secretion (HOMA-B), first and second phase insulin secretion, and insulin secretion-sensitivity index (ISSI) than the NGT group (p ≤ 0.001 for all). Moreover, the GIGT group had lower ISOGTT, HOMA-B, first and second phase insulin secretion, and ISSI than the NGT group (p < 0.001 for all). Among the GIGT subjects, the 1-hour plasma glucose abnormal levels group showed significantly greater weight gain during pregnancy and higher values in the 50-g OGCT than the other two groups. Moreover, the 1-hour and 2-hour abnormal levels groups had poorer insulin secretion status than the 3-hour abnormal levels group. Conclusions Korean women with GDM show impairments of both insulin secretion and insulin sensitivity. In addition, GIGT is associated with both β-cell dysfunction and insulin resistance. PMID:23682224

Interrater Reliability and Diagnostic Performance of Subjective Evaluation of Sublingual Microcirculation Images by Physicians and Nurses: A Multicenter Observational Study.

PubMed

Lima, Alexandre; López, Alejandra; van Genderen, Michel E; Hurtado, Francisco Javier; Angulo, Martin; Grignola, Juan C; Shono, Atsuko; van Bommel, Jasper

2015-09-01

This was a cross-sectional multicenter study to investigate the ability of physicians and nurses from three different countries to subjectively evaluate sublingual microcirculation images and thereby discriminate normal from abnormal sublingual microcirculation based on flow and density abnormalities. Forty-five physicians and 61 nurses (mean age, 36 ± 10 years; 44 males) from three different centers in The Netherlands (n = 61), Uruguay (n = 12), and Japan (n = 33) were asked to subjectively evaluate a sample of 15 microcirculation videos randomly selected from an experimental model of endotoxic shock in pigs. All videos were first analyzed offline using the A.V.A. software by an independent, experienced investigator and were categorized as good, bad, or very bad microcirculation based on the microvascular flow index, perfused capillary density, and proportion of perfused capillaries. Then, the videos were randomly assigned to the examiners, who were instructed to subjectively categorize each image as good, bad, or very bad. An interrater analysis was performed, and sensitivity and specificity tests were calculated to evaluate the proportion of A.V.A. score abnormalities that the examiners correctly identified. The κ statistics indicated moderate agreement in the evaluation of microcirculation abnormalities using three categories, i.e., good, bad, or very bad (κ = 0.48), and substantial agreement using two categories, i.e., normal (good) and abnormal (bad or very bad) (κ = 0.66). There was no significant difference between the κ three and κ two statistics. We found that the examiner's subjective evaluations had good diagnostic performance and were highly sensitive (84%; 95% confidence interval, 81%-86%) and specific (87%; 95% confidence interval, 84%-90%) for sublingual microcirculatory abnormalities as assessed using the A.V.A. software. The subjective evaluations of sublingual microcirculation by physicians and nurses agreed well with a conventional offline analysis and were highly sensitive and specific for sublingual microcirculatory abnormalities.

Diagnosis of mild chronic pancreatitis (Cambridge classification): comparative study using secretin injection-magnetic resonance cholangiopancreatography and endoscopic retrograde pancreatography.

PubMed

Sai, Jin-Kan; Suyama, Masafumi; Kubokawa, Yoshihiro; Watanabe, Sumio

2008-02-28

To investigate the usefulness of secretin injection-MRCP for the diagnosis of mild chronic pancreatitis. Sixteen patients having mild chronic pancreatitis according to the Cambridge classification and 12 control subjects with no abnormal findings on the pancreatogram were examined for the diagnostic accuracy of secretin injection-MRCP regarding abnormal branch pancreatic ducts associated with mild chronic pancreatitis (Cambridge Classification), using endoscopic retrograde cholangiopancreatography (ERCP) for comparison. The sensitivity and specificity for abnormal branch pancreatic ducts determined by two reviewers were respectively 55%-63% and 75%-83% in the head, 57%-64% and 82%-83% in the body, and 44%-44% and 72%-76% in the tail of the pancreas. The sensitivity and specificity for mild chronic pancreatitis were 56%-63% and 92%-92%, respectively. Interobserver agreement (kappa statistics) concerning the diagnosis of an abnormal branch pancreatic duct and of mild chronic pancreatitis was good to excellent. Secretin injection-MRCP might be useful for the diagnosis of mild chronic pancreatitis.

The sensitivity of clinical diagnostic methods in the diagnosis of diabetic neuropathy.

PubMed

Onde, M E; Ozge, A; Senol, M G; Togrol, E; Ozdag, F; Saracoglu, M; Misirli, H

2008-01-01

This study assessed the sensitivity of various methods for the clinical diagnosis of diabetic peripheral neuropathy. A total of 147 randomly selected patients with diabetes mellitus and 65 age- and sex-matched healthy controls were evaluated by various clinical (the neuropathy symptom score [NSS], the neuropathy disability score [NDS], vibration perception thresholds [VPTs], Tinel's sign and Phalen's sign), laboratory (fasting plasma glucose and glycosylated haemoglobin levels) and electro-physiological (nerve conduction studies, H-reflex and F-wave measurements) methods. In the patient group, 8.2% had an abnormal NSS, 28.5% had a positive Phalen's sign, 32.6% had a positive Tinel's sign, 42.8% had an abnormal VPT and 57.1% had an abnormal NDS. Significant correlations were found between electro-physiologically confirmed neuropathy and the two provocation tests and abnormal VPTs. In conclusion, assessment with a complete neurological examination and standard electrophysiological tests is very important for the diagnosis of diabetic peripheral neuropathy and the prevention of morbidity in patients with or without symptoms.

Leptin in human physiology and pathophysiology

PubMed Central

Magkos, Faidon; Brinkoetter, Mary; Sienkiewicz, Elizabeth; Dardeno, Tina A.; Kim, Sang-Yong; Hamnvik, Ole-Petter R.; Koniaris, Anastasia

2011-01-01

Leptin, discovered through positional cloning 15 years ago, is an adipocyte-secreted hormone with pleiotropic effects in the physiology and pathophysiology of energy homeostasis, endocrinology, and metabolism. Studies in vitro and in animal models highlight the potential for leptin to regulate a number of physiological functions. Available evidence from human studies indicates that leptin has a mainly permissive role, with leptin administration being effective in states of leptin deficiency, less effective in states of leptin adequacy, and largely ineffective in states of leptin excess. Results from interventional studies in humans demonstrate that leptin administration in subjects with congenital complete leptin deficiency or subjects with partial leptin deficiency (subjects with lipoatrophy, congenital or related to HIV infection, and women with hypothalamic amenorrhea) reverses the energy homeostasis and neuroendocrine and metabolic abnormalities associated with these conditions. More specifically, in women with hypothalamic amenorrhea, leptin helps restore abnormalities in hypothalamic-pituitary-peripheral axes including the gonadal, thyroid, growth hormone, and to a lesser extent adrenal axes. Furthermore, leptin results in resumption of menses in the majority of these subjects and, in the long term, may increase bone mineral content and density, especially at the lumbar spine. In patients with congenital or HIV-related lipoatrophy, leptin treatment is also associated with improvements in insulin sensitivity and lipid profile, concomitant with reduced visceral and ectopic fat deposition. In contrast, leptin's effects are largely absent in the obese hyperleptinemic state, probably due to leptin resistance or tolerance. Hence, another emerging area of research pertains to the discovery and/or usefulness of leptin sensitizers. Results from ongoing studies are expected to further increase our understanding of the role of leptin and the potential clinical applications of leptin or its analogs in human therapeutics. PMID:21791620

The BK(Ca) channels deficiency as a possible reason for radiation-induced vascular hypercontractility.

PubMed

Kyrychenko, Sergii; Tishkin, Sergey; Dosenko, Victor; Ivanova, Irina; Novokhatska, Tatiana; Soloviev, Anatoly

2012-01-01

It is likely that large-conductance Ca²⁺-activated K⁺ (BK(Ca)) channels channelopathy tightly involved in vascular malfunctions and arterial hypertension development. In the present study, we compared the results of siRNAs-induced α-BK(Ca) gene silencing and vascular abnormalities produced by whole-body ionized irradiation in rats. The experimental design comprised RT-PCR and patch clamp technique, thoracic aorta smooth muscle (SM) contractile recordings and arterial blood pressure (BP) measurements on the 30th day after whole body irradiation (6Gy) and following siRNAs KCNMA1 gene silencing in vivo. The expression profile of BK(Ca) mRNA transcripts in SM was significantly decreased in siRNAs-treated rats in a manner similar to irradiated SM. In contrast, the mRNA levels of K(v) and K(ATP) were significantly increased while L-type calcium channels mRNA transcripts demonstrated tendency to increment. The SMCs obtained from irradiated animals and after KCNMA1 gene silencing showed a significant decrease in total K⁺ current density amplitude. Paxilline (500 nM)-sensitive components of outward current were significantly decreased in both irradiated and gene silencing SMCs. KCNMA1 gene silencing increased SM sensitivity to norepinephrine while Ach-induced relaxation had decreased. The silencing of KCNMA1 had no significant effect on BP while radiation produced sustained arterial hypertension. Therefore, radiation alters the form and function of the BK(Ca) channel and this type of channelopathy may contribute to related vascular abnormalities. Nevertheless, it is unlikely that BK(Ca) can operate as a crucial factor for radiation-induced arterial hypertension. Copyright © 2012 Elsevier Inc. All rights reserved.

Objective comparison of lesion detectability in low and medium-energy collimator iodine-123 mIBG images using a channelized Hotelling observer

NASA Astrophysics Data System (ADS)

Gregory, Rebecca A.; Murray, Iain; Gear, Jonathan; Aldridge, Matthew D.; Levine, Daniel; Fowkes, Lucy; Waddington, Wendy A.; Chua, Sue; Flux, Glenn

2017-01-01

Iodine-123 mIBG imaging is widely regarded as a gold standard for diagnostic studies of neuroblastoma and adult neuroendocrine cancer although the optimal collimator for tumour imaging remains undetermined. Low-energy (LE) high-resolution (HR) collimators provide superior spatial resolution. However due to septal penetration of high-energy photons these provide poorer contrast than medium-energy (ME) general-purpose (GP) collimators. LEGP collimators improve count sensitivity. The aim of this study was to objectively compare the lesion detection efficiency of each collimator to determine the optimal collimator for diagnostic imaging. The septal penetration and sensitivity of each collimator was assessed. Planar images of the patient abdomen were simulated with static scans of a Liqui-Phil™ anthropomorphic phantom with lesion-shaped inserts, acquired with LE and ME collimators on 3 different manufacturers’ gamma camera systems (Skylight (Philips), Intevo (Siemens) and Discovery (GE)). Two-hundred normal and 200 single-lesion abnormal images were created for each collimator. A channelized Hotelling observer (CHO) was developed and validated to score the images for the likelihood of an abnormality. The areas under receiver-operator characteristic (ROC) curves, Az, created from the scores were used to quantify lesion detectability. The CHO ROC curves for the LEHR collimators were inferior to the GP curves for all cameras. The LEHR collimators resulted in statistically significantly smaller Azs (p  <  0.05), of on average 0.891  ±  0.004, than for the MEGP collimators, 0.933  ±  0.004. In conclusion, the reduced background provided by MEGP collimators improved 123I mIBG image lesion detectability over LEHR collimators that provided better spatial resolution.

Chronic paroxetine treatment prevents disruption of methamphetamine-sensitive circadian oscillator in a transgenic mouse model of Huntington's disease.

PubMed

Ouk, Koliane; Aungier, Juliet; Cuesta, Marc; Morton, A Jennifer

2018-03-15

Circadian abnormalities seen in Huntington's disease (HD) patients are recapitulated in several HD transgenic mouse models. In mice, alongside the master clock located in the suprachiasmatic nucleus (SCN), two other oscillators may influence circadian behaviour. These are the food-entrainable oscillator (FEO) and the methamphetamine-sensitive circadian oscillator (MASCO). SCN- and MASCO- (but not FEO-) driven rhythms are progressively disrupted in the R6/2 mouse model of HD. MASCO-driven rhythms are induced by chronic treatment with low dose of methamphetamine and characterised by an increase in period length to greater than 24 h. Interestingly, the rhythms mediated by MASCO deteriorate earlier than those mediated by the SCN in R6/2 mice. Here, we used a pharmacological strategy to investigate the mechanisms underlying MASCO-driven rhythms in WT mice. In contrast to methamphetamine, chronic cocaine was ineffective in generating a MASCO-like component of activity although it markedly increased locomotion. Furthermore, neither blocking dopamine (DA) receptors (with the DA antagonist haloperidol) nor blocking neurotransmission by inhibiting the activity of vesicular monoamine transporter (with reserpine) prevented the expression of the MASCO-driven rhythms, although both treatments downregulated locomotor activity. Interestingly, chronic treatment with paroxetine, a serotonin-specific reuptake inhibitor commonly used as antidepressant in HD, was able to restore the expression of MASCO-driven rhythms in R6/2 mice. Thus, MASCO-driven rhythms appear to be mediated by both serotoninergic and dopaminergic systems. This supports the idea that abnormalities in MASCO output may contribute to both the HD circadian and psychiatric phenotype. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-step contrast sensitivity gauge

DOEpatents

Quintana, Enrico C; Thompson, Kyle R; Moore, David G; Heister, Jack D; Poland, Richard W; Ellegood, John P; Hodges, George K; Prindville, James E

2014-10-14

An X-ray contrast sensitivity gauge is described herein. The contrast sensitivity gauge comprises a plurality of steps of varying thicknesses. Each step in the gauge includes a plurality of recesses of differing depths, wherein the depths are a function of the thickness of their respective step. An X-ray image of the gauge is analyzed to determine a contrast-to-noise ratio of a detector employed to generate the image.

Comparison of colonic transit between polyethylene glycol and water as oral contrast vehicles in the CT evaluation of acute appendicitis.

PubMed

Hebert, Jeffrey J; Taylor, Andrew J; Winter, Thomas C

2006-11-01

The objective of our study was to assess the efficacy of a new positive oral contrast agent's ability to reach the colon during CT evaluation of acute appendicitis. Eighty adult emergency department patients who underwent abdominal CT to evaluate for appendicitis were studied. Forty patients received the department's standard dose of 1,600 mL of a water-iodinated contrast mixture (ratio of 2 mL of iodinated contrast material to 100 mL of water) with a standard delay time of 2-2.5 hours from the beginning of contrast medium ingestion. Forty patients were given a new oral contrast mixture of 1,000 mL of polyethylene glycol (PEG) mixed with 30 mL of iodinated contrast agent, and the examination was conducted only 1 hour from inception of contrast administration. Examinations were reviewed for the presence of contrast medium in the cecum and the presence of appendicitis or other abdominal abnormality. Thirty-eight of 40 patients in the PEG group had contrast medium in the colon at 1 hour after contrast administration, 20 of whom had surgically confirmed cases of appendicitis. In five other patients in that group, another cause to explain the patient's complaints was identified on imaging. Only 18 of the 40 patients who received the standard oral preparation had contrast material present in the cecum. Eleven patients in that group had confirmed appendicitis, and four others had another abnormal finding detected at CT. There was a significant difference in the success of contrast medium transit to the colon with these two agents (p < 0.0001). The use of an oral contrast agent composed of PEG and iodinated contrast material provided a marked improvement in oral agent transit to the colon even in patients with intraabdominal inflammation.

The stiff-man syndrome: new pathophysiological aspects from abnormal exteroceptive reflexes and the response to clomipramine, clonidine, and tizanidine.

PubMed Central

Meinck, H M; Ricker, K; Conrad, B

1984-01-01

Neurophysiological investigations of a patient suffering from the stiff-man syndrome revealed that exteroceptive reflexes, in particular those elicited from the skin, were excessively enhanced. In contrast, no abnormalities were found within the monosynaptic reflex arc. Clomipramine injection severely aggravated the clinical symptoms whereas diazepam, clonidine, and tizanidine decreased both muscular stiffness and abnormal exteroceptive reflexes. The hypothesis is put forward that the stiff-man syndrome is a disorder of descending brain-stem systems which exert a net inhibitory control on axial and limb girdle muscle tone as well as on exteroceptive reflex transmission. Detection of abnormal exteroceptive reflex activity in conjunction with neuropharmacological testing might help in the diagnosis of this rare disease. PMID:6707674

Learning of speckle statistics for in vivo and noninvasive characterization of cutaneous wound regions using laser speckle contrast imaging.

PubMed

Basak, Kausik; Dey, Goutam; Mahadevappa, Manjunatha; Mandal, Mahitosh; Sheet, Debdoot; Dutta, Pranab Kumar

2016-09-01

Laser speckle contrast imaging (LSCI) provides a noninvasive and cost effective solution for in vivo monitoring of blood flow. So far, most of the researches consider changes in speckle pattern (i.e. correlation time of speckle intensity fluctuation), account for relative change in blood flow during abnormal conditions. This paper introduces an application of LSCI for monitoring wound progression and characterization of cutaneous wound regions on mice model. Speckle images are captured on a tumor wound region at mice leg in periodic interval. Initially, raw speckle images are converted to their corresponding contrast images. Functional characterization begins with first segmenting the affected area using k-means clustering, taking wavelet energies in a local region as feature set. In the next stage, different regions in wound bed are clustered based on progressive and non-progressive nature of tissue properties. Changes in contrast due to heterogeneity in tissue structure and functionality are modeled using LSCI speckle statistics. Final characterization is achieved through supervised learning of these speckle statistics using support vector machine. On cross evaluation with mice model experiment, the proposed approach classifies the progressive and non-progressive wound regions with an average sensitivity of 96.18%, 97.62% and average specificity of 97.24%, 96.42% respectively. The clinical information yield with this approach is validated with the conventional immunohistochemistry result of wound to justify the ability of LSCI for in vivo, noninvasive and periodic assessment of wounds. Copyright © 2016 Elsevier Inc. All rights reserved.

Sodium sensitive hypertension: renal and adrenal non-modulation in its pathogenesis

NASA Technical Reports Server (NTRS)

Hollenberg, N. K.; Williams, G. H.

1988-01-01

The thrust of this essay will be to organize a growing body of evidence which indicates that an abnormality of the kidney, and the adrenal, involving disordered regulation through the renin-angiotensin system, is responsible for the pathogenesis in about 45% of patients--a discrete subgroup that may be most common cause of hypertension. That fundamental abnormality leads to disordered renal sodium handling and sodium-sensitive hypertension, abnormalities in the renal vascular response to changes in sodium intake and to angiotensin II, blunted decrements of renin release in response to saline or angiotensin II, and an accentuated renal vasodilator response to angiotensin converting enzyme (ACE) inhibition. ACE inhibition not only increases renal blood flow substantially more in these patients than it does in normal subjects, ACE inhibition also restores to normal the renal vascular and adrenal response to angiotensin II, renin release in response to angiotensin II, renal sodium handling--and ultimately blood pressure. Finally, and perhaps most intriguing, similar abnormalities have been found in 50% of the normotensive offspring of patients with essential hypertension and evidence is accruing to indicate that the abnormality is inherited as a Mendelian dominant.

Dynamic changes of striatal and extrastriatal abnormalities in glutaric aciduria type I.

PubMed

Harting, Inga; Neumaier-Probst, Eva; Seitz, Angelika; Maier, Esther M; Assmann, Birgit; Baric, Ivo; Troncoso, Monica; Mühlhausen, Chris; Zschocke, Johannes; Boy, Nikolas P S; Hoffmann, Georg F; Garbade, Sven F; Kölker, Stefan

2009-07-01

In glutaric aciduria type I, an autosomal recessive disease of mitochondrial lysine, hydroxylysine and tryptophan catabolism, striatal lesions are characteristically induced by acute encephalopathic crises during a finite period of brain development (age 3-36 months). The frequency of striatal injury is significantly less in patients diagnosed as asymptomatic newborns by newborn screening. Most previous studies have focused on the onset and mechanism of striatal injury, whereas little is known about neuroradiological abnormalities in pre-symptomatically diagnosed patients and about dynamic changes of extrastriatal abnormalities. Thus, the major aim of the present retrospective study was to improve our understanding of striatal and extrastriatal abnormalities in affected individuals including those diagnosed by newborn screening. To this end, we systematically analysed magnetic resonance imagings (MRIs) in 38 patients with glutaric aciduria type I diagnosed before or after the manifestation of neurological symptoms. To identify brain regions that are susceptible to cerebral injury during acute encephalopathic crises, we compared the frequency of magnetic resonance abnormalities in patients with and without such crises. Major specific changes after encephalopathic crises were found in the putamen (P < 0.001), nucleus caudatus (P < 0.001), globus pallidus (P = 0.012) and ventricles (P = 0.001). Analysis of empirical cumulative distribution frequencies, however, demonstrated that isolated pallidal abnormalities did not significantly differ over time in both groups (P = 0.544) suggesting that isolated pallidal abnormalities are not induced by acute crises--in contrast to striatal abnormalities. The manifestation of motor disability was associated with signal abnormalities in putamen, caudate, pallidum and ventricles. In addition, we found a large number of extrastriatal abnormalities in patients with and without preceding encephalophatic crises. These abnormalities include widening of anterior temporal and sylvian CSF spaces, pseudocysts, signal changes of substantia nigra, nucleus dentatus, thalamus, tractus tegmentalis centralis and supratentorial white matter as well as signs of delayed maturation (myelination and gyral pattern). In contrast to the striatum, extrastriatal abnormalities were variable and could regress or even normalize with time. This includes widening of sylvian fissures, delayed maturation, pallidal signal changes and pseudocysts. Based on these results, we hypothesize that neuroradiological abnormalities and neurological symptoms in glutaric aciduria type I can be explained by overlaying episodes of cerebral alterations including maturational delay of the brain in utero, acute striatal injury during a vulnerable period in infancy and chronic progressive changes that may continue lifelong. This may have widespread consequences for the pathophysiological understanding of this disease, long-term outcomes and therapeutic considerations.

Modulation of Gardos channel activity by oxidants and oxygen tension: effects of 1-chloro-2,4-dinitrobenzene and phenazine methosulphate.

PubMed

Gibson, John S; Muzyamba, Morris C

2004-05-01

We compare the effects of 1-chloro-2,4-dinitrobenzene (CDNB) and phenazine methosulphate (PMS) on Gardos channel activity in normal human red cells. Both stimulate channel activity, both are dependent on the presence of extracellular Ca2+, and neither is affected by inhibitors of protein (de)phosphorylation. Of the two, PMS has a considerably greater effect. In addition, a major difference is that whilst CDNB has a greater stimulatory effect in oxygenated cells, by contrast, PMS is more effective in deoxygenated cells. These actions are correlated with ca. 30% inhibition of the plasma membrane Ca2+ pump (PMCA) and an increased sensitivity of the Gardos channel to Ca2+ (EC50 falling to about 150 nM). These findings are important in understanding how oxidants alter red cell cation permeability and may be relevant to the abnormal permeability phenotype shown by deoxygenated sickle cells.

Temporal Fourier analysis applied to equilibrium radionuclide cineangiography. Importance in the study of global and regional left ventricular wall motion.

PubMed

Cardot, J C; Berthout, P; Verdenet, J; Bidet, A; Faivre, R; Bassand, J P; Bidet, R; Maurat, J P

1982-01-01

Regional and global left ventricular wall motion was assessed in 120 patients using radionuclide cineangiography (RCA) and contrast angiography. Functional imaging procedures based on a temporal Fourier analysis of dynamic image sequences were applied to the study of cardiac contractility. Two images were constructed by taking the phase and amplitude values of the first harmonic in the Fourier transform for each pixel. These two images aided in determining the perimeter of the left ventricle to calculate the global ejection fraction. Regional left ventricular wall motion was studied by analyzing the phase value and by examining the distribution histogram of these values. The accuracy of global ejection fraction calculation was improved by the Fourier technique. This technique increased the sensitivity of RCA for determining segmental abnormalities especially in the left anterior oblique view (LAO).

The Role of Attention in Somatosensory Processing: A Multi-trait, Multi-method Analysis

PubMed Central

Puts, Nicolaas A. J.; Mahone, E. Mark; Edden, Richard A. E.; Tommerdahl, Mark; Mostofsky, Stewart H.

2016-01-01

Sensory processing abnormalities in autism have largely been described by parent report. This study used a multi-method (parent-report and measurement), multi-trait (tactile sensitivity and attention) design to evaluate somatosensory processing in ASD. Results showed multiple significant within-method (e.g., parent report of different traits)/cross-trait (e.g., attention and tactile sensitivity) correlations, suggesting that parent-reported tactile sensory dysfunction and performance-based tactile sensitivity describe different behavioral phenomena. Additionally, both parent-reported tactile functioning and performance-based tactile sensitivity measures were significantly associated with measures of attention. Findings suggest that sensory (tactile) processing abnormalities in ASD are multifaceted, and may partially reflect a more global deficit in behavioral regulation (including attention). Challenges of relying solely on parent-report to describe sensory difficulties faced by children/families with ASD are also highlighted. PMID:27448580

Spatial contrast sensitivity vision loss in children with cortical visual impairment.

PubMed

Good, William V; Hou, Chuan; Norcia, Anthony M

2012-11-19

Although cortical visual impairment (CVI) is the leading cause of bilateral vision impairment in children in Western countries, little is known about the effects of CVI on visual function. The aim of this study was to compare visual evoked potential measures of contrast sensitivity and grating acuity in children with CVI with those of age-matched typically developing controls. The swept parameter visual evoked potential (sVEP) was used to measure contrast sensitivity and grating acuity in 34 children with CVI at 5 months to 5 years of age and in 16 age-matched control children. Contrast thresholds and spatial frequency thresholds (grating acuities) were derived by extrapolating the tuning functions to zero amplitude. These thresholds and maximal suprathreshold response amplitudes were compared between groups. Among 34 children with CVI, 30 had measurable but reduced contrast sensitivity with a median threshold of 10.8% (range 5.0%-30.0% Michelson), and 32 had measurable but reduced grating acuity with median threshold 0.49 logMAR (9.8 c/deg, range 5-14 c/deg). These thresholds were significantly reduced, compared with age-matched control children. In addition, response amplitudes over the entire sweep range for both measures were significantly diminished in children with CVI compared with those of control children. Our results indicate that spatial contrast sensitivity and response amplitudes are strongly affected by CVI. The substantial degree of loss in contrast sensitivity suggests that contrast is a sensitive measure for evaluating vision deficits in patients with CVI.

High prevalence of heartburn and low acid sensitivity in patients with idiopathic achalasia.

PubMed

Ponce, Julio; Ortiz, Vicente; Maroto, Nuria; Ponce, Marta; Bustamante, Marco; Garrigues, Vicente

2011-03-01

Heartburn is frequently reported by patients with achalasia before treatment. However, the esophageal sensitivity to acid as a possible mediator of this symptom has not been previously evaluated. To evaluate the prevalence of gastroesophageal reflux symptoms and the esophageal sensitivity to acid perfusion in patients with untreated achalasia. Forty patients with achalasia were prospectively evaluated. Forty-three patients with gastroesophageal reflux disease comprised the control group (ten of them with Barrett's esophagus). Symptoms were evaluated by a structured clinical questionnaire. Objective assessment was performed by ambulatory 24-h esophageal pH monitoring and endoscopy. Esophageal sensitivity to acid was evaluated by esophageal perfusion of ClH 0.1 N. Fifteen (37%) of the 40 patients with achalasia presented heartburn, but only four of them had esophagitis and/or abnormal esophageal pH recording. Eight patients had abnormal pH recording. Three patients had esophagitis. The esophagus was sensitive to acid in seven (17%) patients with achalasia, three of them with heartburn and one with abnormal pH recording. In the control group, 40 of 43 (93%) presented heartburn. Acid perfusion was positive in 32 (74%). Sensitivity to acid was lower in patients with achalasia than in those with gastroesophageal reflux disease with or without Barrett's esophagus. The prevalence of heartburn in patients with achalasia is high, although its association with objective indicators of gastroesophageal reflux disease is weak. Patients with achalasia have lower esophageal sensitivity to acid than patients with GERD, suggesting that heartburn is does not arise from this condition.

Scan-stratified case-control sampling for modeling blood-brain barrier integrity in multiple sclerosis.

PubMed

Pomann, Gina-Maria; Sweeney, Elizabeth M; Reich, Daniel S; Staicu, Ana-Maria; Shinohara, Russell T

2015-09-10

Multiple sclerosis (MS) is an immune-mediated neurological disease that causes morbidity and disability. In patients with MS, the accumulation of lesions in the white matter of the brain is associated with disease progression and worse clinical outcomes. Breakdown of the blood-brain barrier in newer lesions is indicative of more active disease-related processes and is a primary outcome considered in clinical trials of treatments for MS. Such abnormalities in active MS lesions are evaluated in vivo using contrast-enhanced structural MRI, during which patients receive an intravenous infusion of a costly magnetic contrast agent. In some instances, the contrast agents can have toxic effects. Recently, local image regression techniques have been shown to have modest performance for assessing the integrity of the blood-brain barrier based on imaging without contrast agents. These models have centered on the problem of cross-sectional classification in which patients are imaged at a single study visit and pre-contrast images are used to predict post-contrast imaging. In this paper, we extend these methods to incorporate historical imaging information, and we find the proposed model to exhibit improved performance. We further develop scan-stratified case-control sampling techniques that reduce the computational burden of local image regression models, while respecting the low proportion of the brain that exhibits abnormal vascular permeability. Copyright © 2015 John Wiley & Sons, Ltd.

Differential effects of exogenous and endogenous attention on second-order texture contrast sensitivity

PubMed Central

Barbot, Antoine; Landy, Michael S.; Carrasco, Marisa

2012-01-01

The visual system can use a rich variety of contours to segment visual scenes into distinct perceptually coherent regions. However, successfully segmenting an image is a computationally expensive process. Previously we have shown that exogenous attention—the more automatic, stimulus-driven component of spatial attention—helps extract contours by enhancing contrast sensitivity for second-order, texture-defined patterns at the attended location, while reducing sensitivity at unattended locations, relative to a neutral condition. Interestingly, the effects of exogenous attention depended on the second-order spatial frequency of the stimulus. At parafoveal locations, attention enhanced second-order contrast sensitivity to relatively high, but not to low second-order spatial frequencies. In the present study we investigated whether endogenous attention—the more voluntary, conceptually-driven component of spatial attention—affects second-order contrast sensitivity, and if so, whether its effects are similar to those of exogenous attention. To that end, we compared the effects of exogenous and endogenous attention on the sensitivity to second-order, orientation-defined, texture patterns of either high or low second-order spatial frequencies. The results show that, like exogenous attention, endogenous attention enhances second-order contrast sensitivity at the attended location and reduces it at unattended locations. However, whereas the effects of exogenous attention are a function of the second-order spatial frequency content, endogenous attention affected second-order contrast sensitivity independent of the second-order spatial frequency content. This finding supports the notion that both exogenous and endogenous attention can affect second-order contrast sensitivity, but that endogenous attention is more flexible, benefitting performance under different conditions. PMID:22895879

First- and second-order contrast sensitivity functions reveal disrupted visual processing following mild traumatic brain injury.

PubMed

Spiegel, Daniel P; Reynaud, Alexandre; Ruiz, Tatiana; Laguë-Beauvais, Maude; Hess, Robert; Farivar, Reza

2016-05-01

Vision is disrupted by traumatic brain injury (TBI), with vision-related complaints being amongst the most common in this population. Based on the neural responses of early visual cortical areas, injury to the visual cortex would be predicted to affect both 1(st) order and 2(nd) order contrast sensitivity functions (CSFs)-the height and/or the cut-off of the CSF are expected to be affected by TBI. Previous studies have reported disruptions only in 2(nd) order contrast sensitivity, but using a narrow range of parameters and divergent methodologies-no study has characterized the effect of TBI on the full CSF for both 1(st) and 2(nd) order stimuli. Such information is needed to properly understand the effect of TBI on contrast perception, which underlies all visual processing. Using a unified framework based on the quick contrast sensitivity function, we measured full CSFs for static and dynamic 1(st) and 2(nd) order stimuli. Our results provide a unique dataset showing alterations in sensitivity for both 1(st) and 2(nd) order visual stimuli. In particular, we show that TBI patients have increased sensitivity for 1(st) order motion stimuli and decreased sensitivity to orientation-defined and contrast-defined 2(nd) order stimuli. In addition, our data suggest that TBI patients' sensitivity for both 1(st) order stimuli and 2(nd) order contrast-defined stimuli is shifted towards higher spatial frequencies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Routine versus selective contrast imaging to identify the need for early re-intervention following laparoscopic fundoplication: A retrospective cohort study.

PubMed

Shahzad, Khalid; Menon, Ashok; Turner, Paul; Ward, Jeremy; Pursnani, Kishore; Alkhaffaf, Bilal

2015-08-01

The prompt recognition of complications is essential in reducing morbidity following anti-reflux surgery. Consequently, many centres employ a policy of routine post-operative contrast studies. The study aimed to examine whether routine contrast studies more effectively recognised early post-operative complications following anti-reflux surgery compared with selective use. This was a retrospective analysis of 240 adults who had undergone primary anti-reflux surgery. Selective use of water-soluble contrast swallows was employed for 115 patients (Group 1) while 125 patients (Group 2) had routine studies. 10 (0.9%) patients from Group 1 underwent contrast studies, four (40%) of which were abnormal. Routine studies in Group 2 identified thirty-two abnormalities (27%) however the inter-group difference was not significant (p = 0.32). Only one case from group 2 required immediate re-intervention. This was not statistically significant (p = 0.78). Multivariate analysis found no significant association between selective or routine imaging and re-intervention rates. One patient from group 2 presented three days following discharge with wrap migration requiring reoperation despite a normal post-operative study. Routine use of contrast imaging following anti-reflux and hiatus hernia surgery is not necessary. It does not identify a significantly greater number of post-operative complications in comparison to selective use. Additionally, routine use of contrast studies does not ensure the diagnosis of all complications in the post-operative period. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

Corneal Sensitivity and Presence of Pathogenic Organisms Among Participants Who Have Undergone Trichiasis Surgery Differ by Surgical Outcome.

PubMed

Schein, Yvette; Harding, Jennifer C; Merbs, Shannath L; Cassard, Sandra D; Mabula, Kasubi; Othman, Majid S; West, Sheila K; Gower, Emily W

2016-04-01

To explore the potential association between reduced corneal sensation and/or conjunctival bacterial colonization and postoperative trichiasis and eyelid contour abnormalities after corrective eyelid surgery among participants with a history of trachomatous trichiasis. As an ancillary study to the Partnership for Rapid Elimination of Trachoma (PRET) Surgery Trial in southern Tanzania, we collected data on 580 PRET participants who had undergone trichiasis surgery 1 year earlier and 200 age-group-matched individuals without trichiasis. Assessments included eyelid status evaluation (presence and severity of postoperative trichiasis and/or eyelid contour abnormality), corneal sensitivity by Cochet-Bonnet aesthesiometer, a questionnaire on symptoms of ocular irritation, and conjunctival microbiology. We divided PRET participants based on their eyelid status and compared results across PRET groups and versus normals. PRET participants had reduced corneal sensitivity compared with age-matched normals (mean sensitivity ranged from 2.8 to 3.8 cm in PRET participants vs. 5.9 cm in normals), and increasing severity of postoperative trichiasis was associated in a stepwise fashion with reduced corneal sensitivity (mean = 3.5 cm for mild and 2.6 cm for severe postoperative trichiasis). Conjunctival colonization with pathogenic bacteria was also associated with more severe postoperative trichiasis (Cochran-Armitage trend test P = 0.001) and with reduced corneal sensitivity (trend test P < 0.0001). Symptoms of ocular irritation were not associated with previous trichiasis surgery, postoperative trichiasis, or eyelid contour abnormality. These findings indicate that reduced corneal sensitivity accompanies trachomatous trichiasis and suggest that reduced corneal sensitivity may play an important role in the harboring of pathogenic bacteria on the ocular surface.

Visual Cortical Function in Very Low Birth Weight Infants without Retinal or Cerebral Pathology

PubMed Central

Hou, Chuan; Norcia, Anthony M.; Madan, Ashima; Tith, Solina; Agarwal, Rashi

2011-01-01

Purpose. Preterm infants are at high risk of visual and neural developmental deficits. However, the development of visual cortical function in preterm infants with no retinal or neurologic morbidity has not been well defined. To determine whether premature birth itself alters visual cortical function, swept parameter visual evoked potential (sVEP) responses of healthy preterm infants were compared with those of term infants. Methods. Fifty-two term infants and 58 very low birth weight (VLBW) infants without significant retinopathy of prematurity or neurologic morbidities were enrolled. Recruited VLBW infants were between 26 and 33 weeks of gestational age, with birth weights of less than 1500 g. Spatial frequency, contrast, and vernier offset sweep VEP tuning functions were measured at 5 to 7 months' corrected age. Acuity and contrast thresholds were derived by extrapolating the tuning functions to 0 amplitude. These thresholds and suprathreshold response amplitudes were compared between groups. Results. Preterm infants showed increased thresholds (indicating decreased sensitivity to visual stimuli) and reductions in amplitudes for all three measures. These changes in cortical responsiveness were larger in the <30 weeks ' gestational age subgroup than in the ≥30 weeks' gestational age subgroup. Conclusions. Preterm infants with VLBW had measurable and significant changes in cortical responsiveness that were correlated with gestational age. These results suggest that premature birth in the absence of identifiable retinal or neurologic abnormalities has a significant effect on visual cortical sensitivity at 5 to 7 months' of corrected age and that gestational age is an important factor in visual development. PMID:22025567

Musculoskeletal MRI findings of juvenile localized scleroderma.

PubMed

Eutsler, Eric P; Horton, Daniel B; Epelman, Monica; Finkel, Terri; Averill, Lauren W

2017-04-01

Juvenile localized scleroderma comprises a group of autoimmune conditions often characterized clinically by an area of skin hardening. In addition to superficial changes in the skin and subcutaneous tissues, juvenile localized scleroderma may involve the deep soft tissues, bones and joints, possibly resulting in functional impairment and pain in addition to cosmetic changes. There is literature documenting the spectrum of findings for deep involvement of localized scleroderma (fascia, muscles, tendons, bones and joints) in adults, but there is limited literature for the condition in children. We aimed to document the spectrum of musculoskeletal magnetic resonance imaging (MRI) findings of both superficial and deep juvenile localized scleroderma involvement in children and to evaluate the utility of various MRI sequences for detecting those findings. Two radiologists retrospectively evaluated 20 MRI studies of the extremities in 14 children with juvenile localized scleroderma. Each imaging sequence was also given a subjective score of 0 (not useful), 1 (somewhat useful) or 2 (most useful for detecting the findings). Deep tissue involvement was detected in 65% of the imaged extremities. Fascial thickening and enhancement were seen in 50% of imaged extremities. Axial T1, axial T1 fat-suppressed (FS) contrast-enhanced and axial fluid-sensitive sequences were rated most useful. Fascial thickening and enhancement were the most commonly encountered deep tissue findings in extremity MRIs of children with juvenile localized scleroderma. Because abnormalities of the skin, subcutaneous tissues and fascia tend to run longitudinally in an affected limb, axial T1, axial fluid-sensitive and axial T1-FS contrast-enhanced sequences should be included in the imaging protocol.

Trivalent dimethylarsenic compound induces histone H3 phosphorylation and abnormal localization of Aurora B kinase in HepG2 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Toshihide, E-mail: toshi-su@pharm.teikyo-u.ac.j; Miyazaki, Koichi; Kita, Kayoko

2009-12-15

Trivalent dimethylarsinous acid [DMA(III)] has been shown to induce mitotic abnormalities, such as centrosome abnormality, multipolar spindles, multipolar division, and aneuploidy, in several cell lines. In order to elucidate the mechanisms underlying these mitotic abnormalities, we investigated DMA(III)-mediated changes in histone H3 phosphorylation and localization of Aurora B kinase, which is a key molecule in cell mitosis. DMA(III) caused the phosphorylation of histone H3 (ser10) and was distributed predominantly in mitotic cells, especially in prometaphase cells. By contrast, most of the phospho-histone H3 was found to be localized in interphase cells after treatment with inorganic arsenite [iAs(III)], suggesting the involvementmore » of a different pathway in phosphorylation. DMA(III) activated Aurora B kinase and slightly activated ERK MAP kinase. Phosphorylation of histone H3 by DMA(III) was effectively reduced by ZM447439 (Aurora kinase inhibitor) and slightly reduced by U0126 (MEK inhibitor). By contrast, iAs(III)-dependent histone H3 phosphorylation was markedly reduced by U0126. Aurora B kinase is generally localized in the midbody during telophase and plays an important role in cytokinesis. However, in some cells treated with DMA(III), Aurora B was not localized in the midbody of telophase cells. These findings suggested that DMA(III) induced a spindle abnormality, thereby activating the spindle assembly checkpoint (SAC) through the Aurora B kinase pathway. In addition, cytokinesis was not completed because of the abnormal localization of Aurora B kinase by DMA(III), thereby resulting in the generation of multinucleated cells. These results provide insight into the mechanism of arsenic tumorigenesis.« less

Instructors' Use of Trigger Warnings and Behavior Warnings in Abnormal Psychology

ERIC Educational Resources Information Center

Boysen, Guy A.; Wells, Anna Mae; Dawson, Kaylee J.

2016-01-01

College students have been increasingly demanding warnings and accommodations in relation to course topics they believe will elicit strong, negative emotions. These "trigger warnings" are highly relevant to Abnormal Psychology because of the sensitive topics covered in the course (e.g., suicide, trauma, sex). A survey of Abnormal…

Staging of breast cancer and the advanced applications of digital mammogram: what the physician needs to know?

PubMed Central

Helal, Maha H; Zaglol, Mai; Salaleldin, Lamia A; Nada, Omniya M; Haggag, Marwa A

2017-01-01

Objective: To study the role of advanced applications of digital mammogram, whether contrast-enhanced spectral mammography (CESM) or digital breast tomosynthesis (DBT), in the “T” staging of histologically proven breast cancer before planning for treatment management. Methods: In this prospective analysis, we evaluated 98 proved malignant breast masses regarding their size, multiplicity and the presence of associated clusters of microcalcifications. Evaluation methods included digital mammography (DM), 3D tomosynthesis and CESM. Traditional DM was first performed then in a period of 10–14-day interval; breast tomosynthesis and contrast-based mammography were performed for the involved breast only. Views at tomosynthesis were acquired in a “step-and-shoot” tube motion mode to produce multiple (11–15), low-dose images and in contrast-enhanced study, low-energy (22–33 kVp) and high-energy (44–49 kVp) exposures were taken after the i.v. injection of the contrast agent. Operative data were the gold standard reference. Results: Breast tomosynthesis showed the highest accuracy in size assessment (n = 69, 70.4%) than contrast-enhanced (n = 49, 50%) and regular mammography (n = 59, 60.2%). Contrast-enhanced mammography presented the least performance in assessing calcifications, yet it was most sensitive in the detection of multiplicity (92.3%), followed by tomosynthesis (77%) and regular mammography (53.8%). The combined analysis of the three modalities provided an accuracy of 74% in the “T” staging of breast cancer. Conclusion: The combined application of tomosynthesis and contrast-enhanced digital mammogram enhanced the performance of the traditional DM and presented an informative method in the staging of breast cancer. Advances in knowledge: Staging and management planning of breast cancer can divert according to tumour size, multiplicity and the presence of microcalcifications. DBT shows sharp outlines of the tumour with no overlap tissue and spots microcalcifications. Contrast-enhanced spectral mammogram shows the extent of abnormal contrast uptake and detects multiplicity. Integrated analysis provides optimal findings for proper “T” staging of breast cancer. PMID:28055247

Functional Lateralization of Speech Processing in Adults and Children Who Stutter

PubMed Central

Sato, Yutaka; Mori, Koichi; Koizumi, Toshizo; Minagawa-Kawai, Yasuyo; Tanaka, Akihiro; Ozawa, Emi; Wakaba, Yoko; Mazuka, Reiko

2011-01-01

Developmental stuttering is a speech disorder in fluency characterized by repetitions, prolongations, and silent blocks, especially in the initial parts of utterances. Although their symptoms are motor related, people who stutter show abnormal patterns of cerebral hemispheric dominance in both anterior and posterior language areas. It is unknown whether the abnormal functional lateralization in the posterior language area starts during childhood or emerges as a consequence of many years of stuttering. In order to address this issue, we measured the lateralization of hemodynamic responses in the auditory cortex during auditory speech processing in adults and children who stutter, including preschoolers, with near-infrared spectroscopy. We used the analysis–resynthesis technique to prepare two types of stimuli: (i) a phonemic contrast embedded in Japanese spoken words (/itta/ vs. /itte/) and (ii) a prosodic contrast (/itta/ vs. /itta?/). In the baseline blocks, only /itta/ tokens were presented. In phonemic contrast blocks, /itta/ and /itte/ tokens were presented pseudo-randomly, and /itta/ and /itta?/ tokens in prosodic contrast blocks. In adults and children who do not stutter, there was a clear left-hemispheric advantage for the phonemic contrast compared to the prosodic contrast. Adults and children who stutter, however, showed no significant difference between the two stimulus conditions. A subject-by-subject analysis revealed that not a single subject who stutters showed a left advantage in the phonemic contrast over the prosodic contrast condition. These results indicate that the functional lateralization for auditory speech processing is in disarray among those who stutter, even at preschool age. These results shed light on the neural pathophysiology of developmental stuttering. PMID:21687442

Mesh-free based variational level set evolution for breast region segmentation and abnormality detection using mammograms.

PubMed

Kashyap, Kanchan L; Bajpai, Manish K; Khanna, Pritee; Giakos, George

2018-01-01

Automatic segmentation of abnormal region is a crucial task in computer-aided detection system using mammograms. In this work, an automatic abnormality detection algorithm using mammographic images is proposed. In the preprocessing step, partial differential equation-based variational level set method is used for breast region extraction. The evolution of the level set method is done by applying mesh-free-based radial basis function (RBF). The limitation of mesh-based approach is removed by using mesh-free-based RBF method. The evolution of variational level set function is also done by mesh-based finite difference method for comparison purpose. Unsharp masking and median filtering is used for mammogram enhancement. Suspicious abnormal regions are segmented by applying fuzzy c-means clustering. Texture features are extracted from the segmented suspicious regions by computing local binary pattern and dominated rotated local binary pattern (DRLBP). Finally, suspicious regions are classified as normal or abnormal regions by means of support vector machine with linear, multilayer perceptron, radial basis, and polynomial kernel function. The algorithm is validated on 322 sample mammograms of mammographic image analysis society (MIAS) and 500 mammograms from digital database for screening mammography (DDSM) datasets. Proficiency of the algorithm is quantified by using sensitivity, specificity, and accuracy. The highest sensitivity, specificity, and accuracy of 93.96%, 95.01%, and 94.48%, respectively, are obtained on MIAS dataset using DRLBP feature with RBF kernel function. Whereas, the highest 92.31% sensitivity, 98.45% specificity, and 96.21% accuracy are achieved on DDSM dataset using DRLBP feature with RBF kernel function. Copyright © 2017 John Wiley & Sons, Ltd.

Guidelines to identify abnormalities after childhood urinary tract infections: a prospective audit.

PubMed

Coulthard, Malcolm G; Lambert, Heather J; Vernon, Susan J; Hunter, Elizabeth W; Keir, Michael J

2014-05-01

To compare the childhood urinary tract infection (UTI) guidelines from the Royal College of Physicians (RCP) in 1991 and from National Institute of Health and Care Excellence (NICE) (CG54) in 2007 by measuring their efficiency at detecting urinary tract abnormalities. Children with UTIs within the Newcastle Primary Care Trust (population 70,800 children) were referred and imaged according to the RCP guidelines during 2008, and these were compared to the activity that would have been undertaken if we had implemented the CG54 guidelines, including following them through 2011 to identify those with recurrent UTIs. The numbers of children imaged, the imaging burden and efficiency, and urinary tract abnormalities detected by each guideline. Fewer children would have been imaged by CG54 than RCP (150 vs 427), but its sensitivity was lower, at 44% for detecting scarring, 10% for identifying vesicoureteric reflux and 40% for other abnormalities. Overall, it would have only detected one-quarter of the abnormal cases (8 vs 32) and would have missed five of nine children with scarring, including three with multiple lesions and one with renal impairment. Imposing an age restriction of <8 years to the RCP guidelines would reduce its screening rate by 20% and still detect 90% of the abnormalities. The CG54 guidelines do not alter the imaging efficiency compared to the RCP guidelines, but they are considerably less sensitive.

Low-cost technology for screening uterine cervical cancer.

PubMed Central

Parashari, A.; Singh, V.; Sehgal, A.; Satyanarayana, L.; Sodhani, P.; Gupta, M. M.

2000-01-01

We report on an illuminated, low-cost (Rs 1500 (US$ 36)) magnifying device (Magnivisualizer) for detecting precancerous lesions of the uterine cervix. A total of 403 women attending a maternal and child health care clinic who had abnormal vaginal discharge and related symptoms were referred for detailed pelvic examination and visual inspection by means of the device after the application of 5% (v/v) acetic acid. Pap smears were obtained at the same time. The results were compared with those obtained using colposcopy and/or histology. The Magnivisualizer improved the detection rate of early cancerous lesions from 60%, for unaided visual inspection, to 95%. It also permitted detection of 58% of cases of low-grade dysplasia and 83% of cases of high-grade dysplasia; none of these cases were detectable by unaided visual inspection. For low-grade dysplasia the sensitivity of detection by means of the Magnivisualizer was 57.5%, in contrast with 75.3% for cytological examination. However, the two methodologies had similar sensitivities for higher grades of lesions. The specificity of screening with the Magnivisualizer was 94.3%, while that of cytology was 99%. The cost per screening was approximately US$ 0.55 for the Magnivisualizer and US$ 1.10 for cytology. PMID:10994279

Susceptibility-Weighted Imaging and Quantitative Susceptibility Mapping in the Brain

PubMed Central

Liu, Chunlei; Li, Wei; Tong, Karen A.; Yeom, Kristen W.; Kuzminski, Samuel

2015-01-01

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. PMID:25270052

Assessment of contrast gain signature in inferred magnocellular and parvocellular pathways in patients with glaucoma

PubMed Central

Sun, Hao; Swanson, William H.; Arvidson, Brian; Dul, Mitchell W.

2010-01-01

PURPOSE Contrast gain signatures of inferred magnocellular and parvocellular postreceptoral pathways were assessed for patients with glaucoma using a contrast discrimination paradigm developed by Pokorny and Smith. The potential causes for changes in contrast gain signature were investigated using model simulations of ganglion cell contrast responses. METHODS Foveal contrast discrimination thresholds were measured with a pedestal-Δ-pedestal paradigm developed by Pokorny and Smith (1997). Stimuli were 27 msec luminance increments superimposed on 227 msec pulsed Δ-pedestals. Contrast thresholds and contrast gain signatures mediated by the inferred magnocellular (MC) and parvocellular (PC) pathways were assessed using linear fits to contrast discrimination thresholds at either lower or higher Δ-pedestal contrasts, respectively. Twenty-seven patients with glaucoma were tested, as well as 16 age-similar control subjects free of eye disease. RESULTS Contrast sensitivity and contrast gain signature mediated by the inferred MC pathway were lower for the glaucoma group, and reduced contrast gain signature was correlated with reduced contrast sensitivity (r2=45%, p<0.0005). These two parameters mediated by the inferred PC pathway were little affected for the glaucoma group. Model simulations suggest that the reduced contrast sensitivity and contrast gain signature were consistent with the hypothesis that reduced MC ganglion cell dendritic complexity can lead to reduced effective retinal illuminance, and hence increased semi-saturation contrast of the ganglion cell contrast response functions. CONCLUSIONS The contrast sensitivity and contrast gain signature of the inferred MC pathway were reduced in patients with glaucoma. The results were consistent with a model of ganglion cell dysfunction due to reduced synaptic density. PMID:18501947

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultz, A.W.; Leavitt, W.Z.

A preliminary study was conducted to determine the feasiblllty of uslng neutron radiography for examining ordnance materials. Depleted U and 4140 steel castings in various thicknesses were examined. In addition, a thin section of Be, a grasshopper and a cricket were radiographed to illustrate the ability of neutrons to determine defects in low-density materials. For uranium thicknesses up to 5 in., a contrast sensitivity between 1.5 and 7.5%o was obtained using thermal neutrons, In foil, and industrial x-ray film transfer techniques. For 6 in. of U, a contrast sensitivity between 6.3 and 12.5% was obtained. For U thicknesses up tomore » 6 in., a detail sensitivity of 2.1% was obtained. For thicknesses up to 4 in. of steel, a contrast sensitivity between 1.9 and 9.4% and a detail sensitivity between 0.8 and 3.1% were obtained. For 5.125 and 6 in. of steel, contrast sensitivities between 14.6 and 29.2% and 14.6 and 39.6%, respectively, and detail sensitivities of no less than 4.9% were obtained. Both a contrast and a detail sensitivity of about 5% were obtained in examining a thin section of Be. Recommendations for further studies are given. (auth)« less

Effect of carbon monoxide on plants. [Mimosa pudica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zimmerman, P.W.; Crocker, W.; Hitchcock, A.E.

Of 108 species of plants treated with one per cent carbon monoxide, 45 showed epinastic growth of leaves. Several species showed hyponasty which caused upward curling of leaves. Other effects included: retarded stem elongation; abnormally small new leaves; abnormal yellowing of the leaves, beginning with the oldest; abscission of leaves usually associated with yellowing; and hypertrophied tissues on stems and roots. During recovery an abnormally large number of side shoots arose from latent buds of many species. Motion pictures of Mimosa pudica showed a loss of correlation, normal equilibrium position to gravity, and sensitiveness to contact or heat stimuli; however,more » the leaves moved about more rapidly than those of controls. Since carbon monoxide causes growth rigor and loss of sensitiveness to external stimuli, it is here considered as an anesthetic.« less

Immature visual neural system in children reflected by contrast sensitivity with adaptive optics correction

PubMed Central

Liu, Rong; Zhou, Jiawei; Zhao, Haoxin; Dai, Yun; Zhang, Yudong; Tang, Yong; Zhou, Yifeng

2014-01-01

This study aimed to explore the neural development status of the visual system of children (around 8 years old) using contrast sensitivity. We achieved this by eliminating the influence of higher order aberrations (HOAs) with adaptive optics correction. We measured HOAs, modulation transfer functions (MTFs) and contrast sensitivity functions (CSFs) of six children and five adults with both corrected and uncorrected HOAs. We found that when HOAs were corrected, children and adults both showed improvements in MTF and CSF. However, the CSF of children was still lower than the adult level, indicating the difference in contrast sensitivity between groups cannot be explained by differences in optical factors. Further study showed that the difference between the groups also could not be explained by differences in non-visual factors. With these results we concluded that the neural systems underlying vision in children of around 8 years old are still immature in contrast sensitivity. PMID:24732728

Automated haematology analysis to diagnose malaria

PubMed Central

2010-01-01

For more than a decade, flow cytometry-based automated haematology analysers have been studied for malaria diagnosis. Although current haematology analysers are not specifically designed to detect malaria-related abnormalities, most studies have found sensitivities that comply with WHO malaria-diagnostic guidelines, i.e. ≥ 95% in samples with > 100 parasites/μl. Establishing a correct and early malaria diagnosis is a prerequisite for an adequate treatment and to minimizing adverse outcomes. Expert light microscopy remains the 'gold standard' for malaria diagnosis in most clinical settings. However, it requires an explicit request from clinicians and has variable accuracy. Malaria diagnosis with flow cytometry-based haematology analysers could become an important adjuvant diagnostic tool in the routine laboratory work-up of febrile patients in or returning from malaria-endemic regions. Haematology analysers so far studied for malaria diagnosis are the Cell-Dyn®, Coulter® GEN·S and LH 750, and the Sysmex XE-2100® analysers. For Cell-Dyn analysers, abnormal depolarization events mainly in the lobularity/granularity and other scatter-plots, and various reticulocyte abnormalities have shown overall sensitivities and specificities of 49% to 97% and 61% to 100%, respectively. For the Coulter analysers, a 'malaria factor' using the monocyte and lymphocyte size standard deviations obtained by impedance detection has shown overall sensitivities and specificities of 82% to 98% and 72% to 94%, respectively. For the XE-2100, abnormal patterns in the DIFF, WBC/BASO, and RET-EXT scatter-plots, and pseudoeosinophilia and other abnormal haematological variables have been described, and multivariate diagnostic models have been designed with overall sensitivities and specificities of 86% to 97% and 81% to 98%, respectively. The accuracy for malaria diagnosis may vary according to species, parasite load, immunity and clinical context where the method is applied. Future developments in new haematology analysers such as considerably simplified, robust and inexpensive devices for malaria detection fitted with an automatically generated alert could improve the detection capacity of these instruments and potentially expand their clinical utility in malaria diagnosis. PMID:21118557

Fluorescent nanodiamond tracking reveals intraneuronal transport abnormalities induced by brain-disease-related genetic risk factors

NASA Astrophysics Data System (ADS)

Haziza, Simon; Mohan, Nitin; Loe-Mie, Yann; Lepagnol-Bestel, Aude-Marie; Massou, Sophie; Adam, Marie-Pierre; Le, Xuan Loc; Viard, Julia; Plancon, Christine; Daudin, Rachel; Koebel, Pascale; Dorard, Emilie; Rose, Christiane; Hsieh, Feng-Jen; Wu, Chih-Che; Potier, Brigitte; Herault, Yann; Sala, Carlo; Corvin, Aiden; Allinquant, Bernadette; Chang, Huan-Cheng; Treussart, François; Simonneau, Michel

2017-05-01

Brain diseases such as autism and Alzheimer's disease (each inflicting >1% of the world population) involve a large network of genes displaying subtle changes in their expression. Abnormalities in intraneuronal transport have been linked to genetic risk factors found in patients, suggesting the relevance of measuring this key biological process. However, current techniques are not sensitive enough to detect minor abnormalities. Here we report a sensitive method to measure the changes in intraneuronal transport induced by brain-disease-related genetic risk factors using fluorescent nanodiamonds (FNDs). We show that the high brightness, photostability and absence of cytotoxicity allow FNDs to be tracked inside the branches of dissociated neurons with a spatial resolution of 12 nm and a temporal resolution of 50 ms. As proof of principle, we applied the FND tracking assay on two transgenic mouse lines that mimic the slight changes in protein concentration (∼30%) found in the brains of patients. In both cases, we show that the FND assay is sufficiently sensitive to detect these changes.

[Abnormality of blood coagulation indexes in patients with de novo acute leukemia and its clinical significance].

PubMed

Xiao, Fang-Fang; Hu, Kai-Xun; Guo, Mei; Qiao, Jian-Hui; Sun, Qi-Yun; Ai, Hui-Sheng; Yu, Chang-Lin

2013-04-01

To explore hemorrhage risk and the clinical significance of abnormal change of prothrombin time (PT), activated partial thromboplastin time (APTT), plasma fibrinogen (FIB), plasma thrombin time (TT) and d-dimer (D-D) in de novo acute leukemia (except for APL), the different bleeding manifestations of 114 cases of de novo acute leukemia with different coagulation indexes were analyzed retrospectively. The correlation between these blood coagulation indexes and the possible correlative clinical characteristics were analysed, including age, sex, type of acute leukemia, initial white blood cell(WBC) and platelet(Plt) count, the proportion of blast cells in bone marrow and cytogenetic abnormality of patients at diagnosis. The results indicated that the incidence of abnormal blood coagulation was as high as 78.1% for de novo AL patients. These patients with 5 normal blood coagulation indexes may have mild bleeding manifestation, but the more abnormal indexes, the more severe bleeding. Both PT and D-D were sensitive indexes for diagnosis of level II bleeding. Incidence of abnormal blood coagulation significantly correlates with the proportion of blast cells in bone marrow (χ(2) = 4.184, OR = 1.021, P < 0.05) and more with D-D (P < 0.01), while age, sex, type of AL, WBC count, Plt count and abnormality of cytogenetics did not correlate with abnormal blood coagulation. It is concluded that the coagulation and fibrinolysis are abnormal in most patients with de novo acute leukemia. More abnormal indexes indicate more severe bleeding, and both PT and D-D are sensitive indexes for diagnosis of level II bleeding. Higher proportion of blast cells in bone marrow predicts higher incidence of abnormal blood clotting. Acute leukemia with elderly age, high white blood cell count and adverse cytogenetics do not predict severer abnormal blood clotting. Detection of PT, APTT, TT, FIB, and D-D may help to judge whether the patients are in a state of hypercoagulability or disseminated intravenous coagulation, which will provide experiment evidences for early intervention and medication.

Sequential contrast-enhanced MR imaging of the penis.

PubMed

Kaneko, K; De Mouy, E H; Lee, B E

1994-04-01

To determine the enhancement patterns of the penis at magnetic resonance (MR) imaging. Sequential contrast material-enhanced MR images of the penis in a flaccid state were obtained in 16 volunteers (12 with normal penile function and four with erectile dysfunction). Subjects with normal erectile function showed gradual and centrifugal enhancement of the corpora cavernosa, while those with erectile dysfunction showed poor enhancement with abnormal progression. Sequential contrast-enhanced MR imaging provides additional morphologic information for the evaluation of erectile dysfunction.

Clinically severe Epstein-Barr virus encephalitis with mild cerebrospinal fluid abnormalities in an immunocompetent adolescent: a case report.

PubMed

Engelmann, Ilka; Nasser, Hala; Belmiloudi, Soufien; Le Guern, Rémi; Dewilde, Anny; Vallée, Louis; Hober, Didier

2013-06-01

A 15-year-old boy developed Epstein-Barr virus (EBV) encephalitis, a rare complication of infectious mononucleosis. The severe clinical picture and the marked neuroimaging changes were in contrast with mild cerebrospinal fluid abnormalities: leukocyte count was normal and protein level was only slightly elevated. EBV DNA was detected in cerebrospinal fluid by polymerase chain reaction. Copyright © 2013 Elsevier Inc. All rights reserved.

Comparison of DWI and PET/CT in evaluation of lymph node metastasis in uterine cancer

PubMed Central

Kitajima, Kazuhiro; Yamasaki, Erena; Kaji, Yasushi; Murakami, Koji; Sugimura, Kazuro

2012-01-01

AIM: To investigate diffusion-weighted imaging (DWI) and positron emission tomography and computed tomography (PET/CT) with IV contrast for the preoperative evaluation of pelvic lymph node (LN) metastasis in uterine cancer. METHODS: Twenty-five patients with endometrial or cervical cancer who underwent both DWI and PET/CT before pelvic lymphadenectomy were included in this study. For area specific analysis, LNs were divided into eight regions: both common iliac, external iliac, internal iliac areas, and obturator areas. The classification for malignancy on DWI was a focally abnormal signal intensity in a location that corresponded to the LN chains on the T1WI and T2WI. The criterion for malignancy on PET/CT images was increased tracer uptake by the LN. RESULTS: A total of 36 pathologically positive LN areas were found in 9 patients. With DWI, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for detecting metastatic LNs on an LN area-by-area analysis were 83.3%, 51.2%, 27.3%, 93.3% and 57.0%, respectively, while the corresponding values for PET/CT were 38.9%, 96.3%, 70.0%, 87.8% and 86.0%. Differences in sensitivity, specificity and accuracy were significant (P < 0.0005). CONCLUSION: DWI showed higher sensitivity and lower specificity than PET/CT. Neither DWI nor PET/CT were sufficiently accurate to replace lymphadenectomy. PMID:22761980

Genetic influence on contrast sensitivity in middle-aged male twins.

PubMed

Cronin-Golomb, Alice; Panizzon, Matthew S; Lyons, Michael J; Franz, Carol E; Grant, Michael D; Jacobson, Kristen C; Eisen, Seth A; Laudate, Thomas M; Kremen, William S

2007-07-01

Contrast sensitivity is strongly associated with daily functioning among older adults, but the genetic and environmental contributions to this ability are unknown. Using the classical twin method, we addressed this issue by examining contrast sensitivity at five spatial frequencies (1.5-18 cycles per degree) in 718 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). Heritability estimates were modest (14-38%), whereas individual-specific environmental influences accounted for 62-86% of the variance. Identifying the types of individual-specific events that impact contrast sensitivity may suggest interventions to modulate this ability and thereby improve overall quality of life as adults age.

Effect of aberrations in human eye on contrast sensitivity function

NASA Astrophysics Data System (ADS)

Quan, Wei; Wang, Feng-lin; Wang, Zhao-qi

2011-06-01

The quantitative analysis of the effect of aberrations in human eye on vision has important clinical value in the correction of aberrations. The wave-front aberrations of human eyes were measured with the Hartmann-Shack wave-front sensor and modulation transfer function (MTF) was computed from the wave-front aberrations. Contrast sensitivity function (CSF) was obtained from MTF and the retinal aerial image modulation (AIM). It is shown that the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations deteriorate contrast sensitivity function. When the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations are corrected high contrast sensitivity function can be obtained.

Hand-arm vibration syndrome: clinical characteristics, conventional electrophysiology and quantitative sensory testing.

PubMed

Rolke, Roman; Rolke, Silke; Vogt, Thomas; Birklein, Frank; Geber, Christian; Treede, Rolf-Detlef; Letzel, Stephan; Voelter-Mahlknecht, Susanne

2013-08-01

Workers exposed to vibrating tools may develop hand-arm vibration syndrome (HAVS). We assessed the somatosensory phenotype using quantitative sensory testing (QST) in comparison to electrophysiology to characterize (1) the most sensitive QST parameter for detecting sensory loss, (2) the correlation of QST and electrophysiology, and (3) the frequency of a carpal tunnel syndrome (CTS) in HAVS. QST, cold provocation tests, fine motor skills, and median nerve neurography were used. QST included thermal and mechanical detection and pain thresholds. Thirty-two patients were examined (54 ± 11 years, 91% men) at the more affected hand compared to 16 matched controls. Vibration detection threshold was the most sensitive parameter to detect sensory loss that was more pronounced in the sensitivity range of Pacinian (150 Hz, x12) than Meissner's corpuscles (20 Hz, x3). QST (84% abnormal) was more sensitive to detect neural dysfunction than conventional electrophysiology (37% abnormal). Motor (34%) and sensory neurography (25%) were abnormal in HAVS. CTS frequency was not increased (9.4%). Findings are consistent with a mechanically-induced, distally pronounced motor and sensory neuropathy independent of CTS. HAVS involves a neuropathy predominantly affecting large fibers with a sensory damage related to resonance frequencies of vibrating tools. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Comparative sensitivity of commercially available aPTT reagents to mulga snake (Pseudechis australis) venom.

PubMed

Lincz, Lisa F; Scorgie, Fiona E; Johnston, Christopher I; O'Leary, Margaret; Prasad, Ritam; Seldon, Michael; Favaloro, Emmanuel; Isbister, Geoffrey K

2014-08-01

This study aimed to determine the relative sensitivity of activated partial thromboplastin time (aPTT) reagents to the anticoagulant effects of phospholipases in mulga snake (Pseudechis australis) venom.Twenty-one haematology laboratories participating in the Royal College of Pathologists of Australasia Quality Assurance Programs were sent human plasma samples spiked with mulga venom (n=25 total results). Results for 17 patients with mulga snake envenoming were available through the Australian Snakebite Project.Only 12 of 25 venom spiked samples returned an abnormally prolonged aPTT. Tests performed with Dade Actin FS (n=7) did not identify any of the spiked samples as abnormal. Although clotting times were significantly prolonged using the lupus anticoagulant sensitive Actin FSL (n=5, p=0.043), only one was reported as abnormal. Only laboratories using TriniCLOT aPTT S (n=6), HemosIL APTT SP (n=2) and Stago PTT-A (n=1) consistently recorded the spiked sample as being above the upper normal reference interval. Abnormally prolonged aPTTs were recorded for four of eight patients whose tests were performed with Actin FSL, five of eight patients with TriniCLOT aPTT HS, and three of three patients using TriniCLOT aPTT S.We conclude that some reagents used for routine aPTT testing are relatively insensitive to the anticoagulant effects of mulga snake venom. Tests performed with these reagents should be interpreted with caution.

Added diagnostic value of magnetoencephalography (MEG) in patients suspected for epilepsy, where previous, extensive EEG workup was unrevealing.

PubMed

Duez, Lene; Beniczky, Sándor; Tankisi, Hatice; Hansen, Peter Orm; Sidenius, Per; Sabers, Anne; Fuglsang-Frederiksen, Anders

2016-10-01

To elucidate the possible additional diagnostic yield of MEG in the workup of patients with suspected epilepsy, where repeated EEGs, including sleep-recordings failed to identify abnormalities. Fifty-two consecutive patients with clinical suspicion of epilepsy and at least three normal EEGs, including sleep-EEG, were prospectively analyzed. The reference standard was inferred from the diagnosis obtained from the medical charts, after at least one-year follow-up. MEG (306-channel, whole-head) and simultaneous EEG (MEG-EEG) was recorded for one hour. The added sensitivity of MEG was calculated from the cases where abnormalities were seen in MEG but not EEG. Twenty-two patients had the diagnosis epilepsy according to the reference standard. MEG-EEG detected abnormalities, and supported the diagnosis in nine of the 22 patients with the diagnosis epilepsy at one-year follow-up. Sensitivity of MEG-EEG was 41%. The added sensitivity of MEG was 18%. MEG-EEG was normal in 28 of the 30 patients categorized as 'not epilepsy' at one year follow-up, yielding a specificity of 93%. MEG provides additional diagnostic information in patients suspected for epilepsy, where repeated EEG recordings fail to demonstrate abnormality. MEG should be included in the diagnostic workup of patients where the conventional, widely available methods are unrevealing. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Effect of color coding and subtraction on the accuracy of contrast echocardiography

NASA Technical Reports Server (NTRS)

Pasquet, A.; Greenberg, N.; Brunken, R.; Thomas, J. D.; Marwick, T. H.

1999-01-01

BACKGROUND: Contrast echocardiography may be used to assess myocardial perfusion. However, gray scale assessment of myocardial contrast echocardiography (MCE) is difficult because of variations in regional backscatter intensity, difficulties in distinguishing varying shades of gray, and artifacts or attenuation. We sought to determine whether the assessment of rest myocardial perfusion by MCE could be improved with subtraction and color coding. METHODS AND RESULTS: MCE was performed in 31 patients with previous myocardial infarction with a 2nd generation agent (NC100100, Nycomed AS), using harmonic triggered or continuous imaging and gain settings were kept constant throughout the study. Digitized images were post processed by subtraction of baseline from contrast data and colorized to reflect the intensity of myocardial contrast. Gray scale MCE alone, MCE images combined with baseline and subtracted colorized images were scored independently using a 16 segment model. The presence and severity of myocardial contrast abnormalities were compared with perfusion defined by rest MIBI-SPECT. Segments that were not visualized by continuous (17%) or triggered imaging (14%) after color processing were excluded from further analysis. The specificity of gray scale MCE alone (56%) or MCE combined with baseline 2D (47%) was significantly enhanced by subtraction and color coding (76%, p<0.001) of triggered images. The accuracy of the gray scale approaches (respectively 52% and 47%) was increased to 70% (p<0.001). Similarly, for continuous images, the specificity of gray scale MCE with and without baseline comparison was 23% and 42% respectively, compared with 60% after post processing (p<0.001). The accuracy of colorized images (59%) was also significantly greater than gray scale MCE (43% and 29%, p<0.001). The sensitivity of MCE for both acquisitions was not altered by subtraction. CONCLUSION: Post-processing with subtraction and color coding significantly improves the accuracy and specificity of MCE for detection of perfusion defects.

Understanding of the impact of chemicals on amphibians: a meta-analytic review.

PubMed

Egea-Serrano, Andrés; Relyea, Rick A; Tejedo, Miguel; Torralva, Mar

2012-07-01

Many studies have assessed the impact of different pollutants on amphibians across a variety of experimental venues (laboratory, mesocosm, and enclosure conditions). Past reviews, using vote-counting methods, have described pollution as one of the major threats faced by amphibians. However, vote-counting methods lack strong statistical power, do not permit one to determine the magnitudes of effects, and do not compare responses among predefined groups. To address these challenges, we conducted a meta-analysis of experimental studies that measured the effects of different chemical pollutants (nitrogenous and phosphorous compounds, pesticides, road deicers, heavy metals, and other wastewater contaminants) at environmentally relevant concentrations on amphibian survival, mass, time to hatching, time to metamorphosis, and frequency of abnormalities. The overall effect size of pollutant exposure was a medium decrease in amphibian survival and mass and a large increase in abnormality frequency. This translates to a 14.3% decrease in survival, a 7.5% decrease in mass, and a 535% increase in abnormality frequency across all studies. In contrast, we found no overall effect of pollutants on time to hatching and time to metamorphosis. We also found that effect sizes differed among experimental venues and among types of pollutants, but we only detected weak differences among amphibian families. These results suggest that variation in sensitivity to contaminants is generally independent of phylogeny. Some publication bias (i.e., selective reporting) was detected, but only for mass and the interaction effect size among stressors. We conclude that the overall impact of pollution on amphibians is moderately to largely negative. This implies that pollutants at environmentally relevant concentrations pose an important threat to amphibians and may play a role in their present global decline.

Peel flour of Passiflora edulis Var. Flavicarpa supplementation prevents the insulin resistance and hepatic steatosis induced by low-fructose-diet in young rats.

PubMed

Goss, M J; Nunes, M L O; Machado, I D; Merlin, L; Macedo, N B; Silva, A M O; Bresolin, T M B; Santin, J R

2018-06-01

The increase in fructose consumption in the last decades has an important correlation with the growth of overweight population. Fructose is a monosaccharide found in fruits, vegetables and honey, however, it is widely used in processed food and beverages such as sweeteners. This monosaccharide is metabolized in the liver, so it can produce glucose, lactate, triglycerides, free fatty acids and uric acid, which are responsible for negative effects on the liver and extrahepatic tissues. One effect of the high consumption of fructose is the resistance to Insulin, which appears to be an important issue in the development of metabolic abnormalities observed in animals that were subjected to a high fructose diet. The population and, consequently, the market search for natural sources to manage metabolic abnormalities is increasing, but, adequate scientific proof still is necessary. The Passiflora edulis peel flour (PEPF) is a byproduct of the juice industry, and, represents an important source of fiber and bioactive compounds. The present study investigates the PEPF supplementation (30%) effects on insulin sensitivity, adiposity and metabolic parameters in young rats that were given beverages enriched with 10% of fructose for 8 weeks. Fructose intake induced insulin resistance, increased serum triglycerides levels, growth of fat deposits in the liver and widening of the diameter of adipocytes. In contrast, the group that received PEPF did not present such abnormalities, which could be related to the presence of fiber or bioactive compounds (phenolics compounds, e.g., caffeic acid and isoorientin) in its composition, as identified by analytical methods. Thus, for the first time, it has been demonstrated that PEPF supplementation prevents insulin resistance and hepatic steatosis induced by low-fructose-diet in young rats. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Association Between Retinal Nerve Fiber Layer Thickness and Abnormalities of Vision in People With Human Immunodeficiency Virus Infection

PubMed Central

Kalyani, Partho S.; Holland, Gary N.; Fawzi, Amani A.; Arantes, Tiago E.F.; Yu, Fei; Sadun, Alfredo A.

2014-01-01

Purpose To investigate relationships between contrast sensitivity (CS), color vision, and retinal nerve fiber layer (RNFL) among people with human immunodeficiency virus (HIV) infection; to evaluate the effect of time since diagnosis of HIV infection on RNFL thickness. Design Noninterventional cross-sectional study. Methods We evaluated 102 eyes of 57 HIV-infected individuals without ocular opportunistic infections. Peripapillary RNFL thickness was determined with spectraldomain optical coherence tomography in 4 quadrants. CS was measured with the Pelli-Robson technique (expressed as logCS); color vision was measured with the Lanthony desaturated 15-hue technique (expressed as color confusion index [C-index], with higher scores indicating worse color vision). Correlations between values were assessed using Spearman correlation coefficients. Results Median RNFL thickness (average of 4 quadrants) was 102.9 μm (range, 75.0–134.7 μm). Median logCS was 1.90 (range, 1.25–1.95). Median C-index was 1.58 (range, 0.96–4.07). Temporal RNFL thickness was correlated with logCS (r = 0.295, P = .003) and C-index (r = −0.338, P = .0005). Time since diagnosis of HIV infection was shorter for those with thick average RNFL than for those with thin average RNFL (P = .18). Conclusions Both worse CS and worse color vision are correlated with thinning of the temporal RNFL, with possible threshold effects. Increased prevalences of abnormal CS and abnormal color vision in this population are therefore likely attributable to neuroretinal compromise. This pattern of structural and functional losses may reflect preferential damage to small-caliber axons in the maculopapillary bundle, possibly associated with mitochondrial dysfunction, providing a potential disease mechanism for HIV-associated “neuroretinal disorder.” PMID:22245459

Clinical Use of CT Perfusion For Diagnosis and Prediction of Lesion Growth in Acute Ischemic Stroke

PubMed Central

Huisa, Branko N; Neil, William P; Schrader, Ronald; Maya, Marcel; Pereira, Benedict; Bruce, Nhu T; Lyden, Patrick D

2012-01-01

Background and Purpose CT perfusion (CTP) mapping in research centers correlates well with diffusion weighted imaging (DWI) lesions and may accurately differentiate the infarct core from ischemic penumbra. The value of CTP in real-world clinical practice has not been fully established. We investigated the yield of CTP– derived cerebral blood volume (CBV) and mean transient time (MTT) for the detection of cerebral ischemia and ischemic penumbra in a sample of acute ischemic stroke (AIS) patients. Methods We studied 165 patients with initial clinical symptoms suggestive of AIS. All patients had an initial non-contrast head CT, CT Perfusion (CTP), CT angiogram (CTA) and follow up brain MRI. The obtained perfusion images were used for image processing. CBV, MTT and DWI lesion volumes were visually estimated and manually traced. Statistical analysis was done using R-2.14.and SAS 9.1. Results All normal DWI sequences had normal CBV and MTT studies (N=89). Seventy-three patients had acute DWI lesions. CBV was abnormal in 23.3% and MTT was abnormal in 42.5% of these patients. There was a high specificity (91.8%)but poor sensitivity (40.0%) for MTT maps predicting positive DWI. Spearman correlation was significant between MTT and DWI lesions (ρ=0.66, p>0.0001) only for abnormal MTT and DWI lesions>0cc. CBV lesions did not correlate with final DWI. Conclusions In real-world use, acute imaging with CTP did not predict stroke or DWI lesions with sufficient accuracy. Our findings argue against the use of CTP for screening AIS patients until real-world implementations match the accuracy reported from specialized research centers. PMID:23253533

Assessment of contrast gain signature in inferred magnocellular and parvocellular pathways in patients with glaucoma.

PubMed

Sun, Hao; Swanson, William H; Arvidson, Brian; Dul, Mitchell W

2008-11-01

Contrast gain signatures of inferred magnocellular and parvocellular postreceptoral pathways were assessed for patients with glaucoma using a contrast discrimination paradigm developed by Pokorny and Smith. The potential causes for changes in contrast gain signature were investigated using model simulations of ganglion cell contrast responses. Foveal contrast discrimination thresholds were measured with a pedestal-Delta-pedestal paradigm developed by Pokorny and Smith [Pokorny, J., & Smith, V. C. (1997). Psychophysical signatures associated with magnocellular and parvocellular pathway contrast gain. Journal of the Optical Society of America A, 14(9), 2477-2486]. Stimuli were 27 ms luminance increments superimposed on 227 ms pulsed Delta-pedestals. Contrast thresholds and contrast gain signatures mediated by the inferred magnocellular (MC) and parvocellular (PC) pathways were assessed using linear fits to contrast discrimination thresholds at either lower or higher Delta-pedestal contrasts, respectively. Twenty-seven patients with glaucoma were tested, as well as 16 age-similar control subjects free of eye disease. Contrast sensitivity and contrast gain signature mediated by the inferred MC pathway were lower for the glaucoma group, and reduced contrast gain signature was correlated with reduced contrast sensitivity (r(2)=45%, p<.0005). These two parameters mediated by the inferred PC pathway were little affected for the glaucoma group. Model simulations suggest that the reduced contrast sensitivity and contrast gain signature were consistent with the hypothesis that reduced MC ganglion cell dendritic complexity can lead to reduced effective retinal illuminance, and hence increased semi-saturation contrast of the ganglion cell contrast response functions. The contrast sensitivity and contrast gain signature of the inferred MC pathway were reduced in patients with glaucoma. The results were consistent with a model of ganglion cell dysfunction due to reduced synaptic density.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

PubMed Central

Barboni, M.T.S.; Gomes, B.D.; Souza, G.S.; Rodrigues, A.R.; Ventura, D.F.; Silveira, L.C.L.

2013-01-01

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus. PMID:23369980

Anxiety sensitivity and auditory perception of heartbeat.

PubMed

Pollock, R A; Carter, A S; Amir, N; Marks, L E

2006-12-01

Anxiety sensitivity (AS) is the fear of sensations associated with autonomic arousal. AS has been associated with the development and maintenance of panic disorder. Given that panic patients often rate cardiac symptoms as the most fear-provoking feature of a panic attack, AS individuals may be especially responsive to cardiac stimuli. Consequently, we developed a signal-in-white-noise detection paradigm to examine the strategies that high and low AS individuals use to detect and discriminate normal and abnormal heartbeat sounds. Compared to low AS individuals, high AS individuals demonstrated a greater propensity to report the presence of normal, but not abnormal, heartbeat sounds. High and low AS individuals did not differ in their ability to perceive normal heartbeat sounds against a background of white noise; however, high AS individuals consistently demonstrated lower ability to discriminate abnormal heartbeats from background noise and between abnormal and normal heartbeats. AS was characterized by an elevated false alarm rate across all tasks. These results suggest that heartbeat sounds may be fear-relevant cues for AS individuals, and may affect their attention and perception in tasks involving threat signals.

Validation of the colour difference plot scoring system analysis of the 103 hexagon multifocal electroretinogram in the evaluation of hydroxychloroquine retinal toxicity.

PubMed

Graves, Gabrielle S; Adam, Murtaza K; Stepien, Kimberly E; Han, Dennis P

2014-08-01

To evaluate sensitivity, specificity and reproducibility of colour difference plot analysis (CDPA) of 103 hexagon multifocal electroretinogram (mfERG) in detecting established hydroxychloroquine (HCQ) retinal toxicity. Twenty-three patients taking HCQ were divided into those with and without retinal toxicity and were compared with a control group without retinal disease and not taking HCQ. CDPA with two masked examiners was performed using age-corrected mfERG responses in the central ring (Rc ; 0-5.5 degrees from fixation) and paracentral ring (Rp ; 5.5-11 degrees from fixation). An abnormal ring was defined as containing any hexagons with a difference in two or more standard deviations from normal (colour blue or black). Categorical analysis (ring involvement or not) showed Rc had 83% sensitivity and 93% specificity. Rp had 89% sensitivity and 82% specificity. Requiring abnormal hexagons in both Rc and Rp yielded sensitivity and specificity of 83% and 95%, respectively. If required in only one ring, they were 89% and 80%, respectively. In this population, there was complete agreement in identifying toxicity when comparing CDPA using Rp with ring ratio analysis using R5/R4 P1 ring responses (89% sensitivity and 95% specificity). Continuous analysis of CDPA with receiver operating characteristic analysis showed optimized detection (83% sensitivity and 96% specificity) when ≥4 abnormal hexagons were present anywhere within the Rp ring outline. Intergrader agreement and reproducibility were good. Colour difference plot analysis had sensitivity and specificity that approached that of ring ratio analysis of R5/R4 P₁ responses. Ease of implementation and reproducibility are notable advantages of CDPA. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Determining sensitivity/specificity of virtual reality-based neuropsychological tool for detecting residual abnormalities following sport-related concussion.

PubMed

Teel, Elizabeth; Gay, Michael; Johnson, Brian; Slobounov, Semyon

2016-05-01

Computer-based neuropsychological (NP) evaluation is an effective clinical tool used to assess cognitive function which complements the clinical diagnosis of a concussion. However, some researchers and clinicians argue its lack of ecological validity places limitations on externalizing results to a sensory rich athletic environment. Virtual reality-based NP assessment offers clinical advantages using an immersive environment and evaluating domains not typically assessed by traditional NP assessments. The sensitivity and specificity of detecting lingering cognitive abnormalities was examined on components of a virtual reality-based NP assessment battery to cohort affiliation (concussed vs. controls). Data were retrospectively gathered on 128 controls (no concussion) and 24 concussed college-age athletes on measures of spatial navigation, whole body reaction, attention, and balance in a virtual environment. Concussed athletes were tested within 10 days (M = 8.33, SD = 1.06) of concussion and were clinically asymptomatic at the time of testing. A priori alpha level was set at 0.05 for all tests. Spatial navigation (sensitivity 95.8%/specificity 91.4%, d = 1.89), whole body reaction time (sensitivity 95.2%/specificity 89.1%, d = 1.50) and combined virtual reality modules (sensitivity 95.8%,/specificity 96.1%, d = 3.59) produced high sensitivity/specificity values when determining performance-based variability between groups. Use of a virtual reality-based NP platform can detect lingering cognitive abnormalities resulting from concussion in clinically asymptomatic participants. Virtual reality NP platforms may compliment the traditional concussion assessment battery by providing novel information. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The sensitivity and specificity of the neurological examination in polyneuropathy patients with clinical and electrophysiological correlations.

PubMed

Abraham, Alon; Alabdali, Majed; Alsulaiman, Abdulla; Albulaihe, Hana; Breiner, Ari; Katzberg, Hans D; Aljaafari, Danah; Lovblom, Leif E; Bril, Vera

2017-01-01

Polyneuropathy is one of the most prevalent neurologic disorders. Although several studies explored the role of the neurological examination in polyneuropathy, they were mostly restricted to specific subgroups of patients and have not correlated examination findings with symptoms and electrophysiological results. To explore the sensitivity and specificity of different neurological examination components in patients with diverse etiologies for polyneuropathy, find the most sensitive combination of examination components for polyneuropathy detection, and correlate examination findings with symptoms and electrophysiological results. Patients with polyneuropathy attending the neuromuscular clinic from 01/2013 to 09/2015 were evaluated. Inclusion criteria included symptomatic polyneuropathy, which was confirmed by electrophysiological studies. 47 subjects with no symptoms or electrophysiological findings suggestive for polyneuropathy, served as controls. The total cohort included 312 polyneuropathy patients, with a mean age of 60±14 years. Abnormal examination was found in 95%, most commonly sensory findings (86%). The most common abnormal examination components were impaired ankle reflexes (74%), vibration (73%), and pinprick (72%) sensation. Combining ankle reflex examination with vibration or pinprick perception had the highest sensitivity, of 88%. The specificities of individual examination component were generally high, excluding ankle reflexes (62%), and vibration perception (77%). Abnormal examination findings were correlated with symptomatic weakness and worse electrophysiological parameters. The neurological examination is a valid, sensitive and specific tool for diagnosing polyneuropathy, and findings correlate with polyneuropathy severity. Ankle reflex examination combined with either vibration or pinprick sensory testing is the most sensitive combination for diagnosing polyneuropathy, and should be considered minimal essential components of the physical examination in patients with suspected polyneuropathy.

In vivo Diagnosis of Cervical Intraepithelial Neoplasia Using 337-nm- Excited Laser-Induced Fluorescence

NASA Astrophysics Data System (ADS)

Ramanujam, N.; Mitchell, M. F.; Mahadevan, A.; Warren, S.; Thomsen, S.; Silva, E.; Richards-Kortum, R.

1994-10-01

Laser-induced fluorescence at 337-nm excitation was used in vivo to differentiate neoplastic [cervical intraepithelial neoplasia (CIN)], nonneoplastic abnormal (inflammation and human papilloma viral infection), and normal cervical tissues. A colposcope (low-magnification microscope used to view the cervix with reflected light) was used to identify 66 normal and 49 abnormal (5 inflammation, 21 human papilloma virus infection, and 23 CIN) sites on the cervix in 28 patients. These sites were then interrogated spectroscopically. A two-stage algorithm was developed to diagnose CIN. The first stage differentiated histologically abnormal tissues from colposcopically normal tissues with a sensitivity, specificity, and positive predictive value of 92%, 90%, and 88%, respectively. The second stage differentiated preneoplastic and neoplastic tissues from nonneoplastic abnormal tissues with a sensitivity, specificity, and positive predictive value of 87%, 73%, and 74%, respectively. Spectroscopic differences were consistent with a decrease in the absolute contribution of collagen fluorescence, an increase in the absolute contribution of oxyhemoglobin attenuation, and an increase in the relative contribution of reduced nicotinamide dinucleotide phosphate [NAD(P)H] fluorescence as tissue progresses from normal to abnormal in the same patient. These results suggest that in vivo fluorescence spectroscopy of the cervix can be used to diagnose CIN at colposcopy.

A neurophysiological study of facial numbness in multiple sclerosis: Integration with clinical data and imaging findings.

PubMed

Koutsis, Georgios; Kokotis, Panagiotis; Papagianni, Aikaterini E; Evangelopoulos, Maria-Eleftheria; Kilidireas, Constantinos; Karandreas, Nikolaos

2016-09-01

To integrate neurophysiological findings with clinical and imaging data in a consecutive series of multiple sclerosis (MS) patients developing facial numbness during the course of an MS attack. Nine consecutive patients with MS and recent-onset facial numbness were studied clinically, imaged with routine MRI, and assessed neurophysiologically with trigeminal somatosensory evoked potential (TSEP), blink reflex (BR), masseter reflex (MR), facial nerve conduction, facial muscle and masseter EMG studies. All patients had unilateral facial hypoesthesia on examination and lesions in the ipsilateral pontine tegmentum on MRI. All patients had abnormal TSEPs upon stimulation of the affected side, excepting one that was tested following remission of numbness. BR was the second most sensitive neurophysiological method with 6/9 examinations exhibiting an abnormal R1 component. The MR was abnormal in 3/6 patients, always on the affected side. Facial conduction and EMG studies were normal in all patients but one. Facial numbness was always related to abnormal TSEPs. A concomitant R1 abnormality on BR allowed localization of the responsible pontine lesion, which closely corresponded with MRI findings. We conclude that neurophysiological assessment of MS patients with facial numbness is a sensitive tool, which complements MRI, and can improve lesion localization. Copyright © 2016 Elsevier B.V. All rights reserved.

Malignant pleural disease: diagnosis by using diffusion-weighted and dynamic contrast-enhanced MR imaging--initial experience.

PubMed

Coolen, Johan; De Keyzer, Frederik; Nafteux, Philippe; De Wever, Walter; Dooms, Christophe; Vansteenkiste, Johan; Roebben, Ilse; Verbeken, Eric; De Leyn, Paul; Van Raemdonck, Dirk; Nackaerts, Kristiaan; Dymarkowski, Steven; Verschakelen, Johny

2012-06-01

To investigate the use of diffusion-weighted (DW) imaging for differentiating benign lesions from malignant pleural disease (MPD) and to retrospectively assess dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging acquisitions to find out whether combining these measurements with DW imaging could improve the diagnostic value of DW imaging. This study was approved by the local ethics committee, and all patients provided written informed consent. Thirty-one consecutive patients with pleural abnormalities suspicious for MPD underwent whole-body positron emission tomography (PET)/computed tomography (CT) and thorax MR examinations. Diagnostic thoracoscopy with histopathologic analysis of pleural biopsies served as the reference standard. First-line evaluation of each suspicious lesion was performed by using the apparent diffusion coefficient (ADC) calculated from the DW image, and the optimal cutoff value was found by using receiver operating characteristic curve analysis. Afterward, DCE MR imaging data were used to improve the diagnosis in the range of ADCs where DW imaging results were equivocal. Sensitivity, specificity, and accuracy of PET/CT for diagnosis of MPD were 100%, 35.3%, and 64.5%. The optimal ADC threshold to differentiate benign lesions from MPD with DW MR imaging was 1.52 × 10(-3) mm(2)/sec, with sensitivity, specificity, and accuracy of 71.4%, 100%, and 87.1%, respectively. This result could be improved to 92.8%, 94.1%, and 93.5%, respectively, when DCE MR imaging data were included in those cases where ADC was between 1.52 and 2.00 × 10(-3) mm(2)/sec. A total of 20 patients had disease diagnosed correctly, nine had disease diagnosed incorrectly, and two cases were undetermined with PET/CT. DW imaging helped stage disease correctly in 27 patients and incorrectly in four. The undetermined cases at PET/CT were correctly diagnosed at MR imaging. DW imaging is a promising tool for differentiating MPD from benign lesions, with high accuracy, and supplementation with DCE MR imaging seems to further improve sensitivity.

Abnormal Size-Dependent Modulation of Motion Perception in Children with Autism Spectrum Disorder (ASD)

PubMed Central

Sysoeva, Olga V.; Galuta, Ilia A.; Davletshina, Maria S.; Orekhova, Elena V.; Stroganova, Tatiana A.

2017-01-01

Excitation/Inhibition (E/I) imbalance in neural networks is now considered among the core neural underpinnings of autism psychopathology. In motion perception at least two phenomena critically depend on E/I balance in visual cortex: spatial suppression (SS), and spatial facilitation (SF) corresponding to impoverished or improved motion perception with increasing stimuli size, respectively. While SS is dominant at high contrast, SF is evident for low contrast stimuli, due to the prevalence of inhibitory contextual modulations in the former, and excitatory ones in the latter case. Only one previous study (Foss-Feig et al., 2013) investigated SS and SF in Autism Spectrum Disorder (ASD). Our study aimed to replicate previous findings, and to explore the putative contribution of deficient inhibitory influences into an enhanced SF index in ASD—a cornerstone for interpretation proposed by Foss-Feig et al. (2013). The SS and SF were examined in 40 boys with ASD, broad spectrum of intellectual abilities (63 < IQ < 127) and 44 typically developing (TD) boys, aged 6–15 years. The stimuli of small (1°) and large (12°) radius were presented under high (100%) and low (1%) contrast conditions. Social Responsiveness Scale and Sensory Profile Questionnaire were used to assess the autism severity and sensory processing abnormalities. We found that the SS index was atypically reduced, while SF index abnormally enhanced in children with ASD. The presence of abnormally enhanced SF in children with ASD was the only consistent finding between our study and that of Foss-Feig et al. While the SS and SF indexes were strongly interrelated in TD participants, this correlation was absent in their peers with ASD. In addition, the SF index but not the SS index correlated with the severity of autism and the poor registration abilities. The pattern of results is partially consistent with the idea of hypofunctional inhibitory transmission in visual areas in ASD. Nonetheless, the absence of correlation between SF and SS indexes paired with a strong direct link between abnormally enhanced SF and autism symptoms in our ASD sample emphasizes the role of the enhanced excitatory influences by themselves in the observed abnormalities in low-level visual phenomena found in ASD. PMID:28405183

An improved FSL-FIRST pipeline for subcortical gray matter segmentation to study abnormal brain anatomy using quantitative susceptibility mapping (QSM).

PubMed

Feng, Xiang; Deistung, Andreas; Dwyer, Michael G; Hagemeier, Jesper; Polak, Paul; Lebenberg, Jessica; Frouin, Frédérique; Zivadinov, Robert; Reichenbach, Jürgen R; Schweser, Ferdinand

2017-06-01

Accurate and robust segmentation of subcortical gray matter (SGM) nuclei is required in many neuroimaging applications. FMRIB's Integrated Registration and Segmentation Tool (FIRST) is one of the most popular software tools for automated subcortical segmentation based on T 1 -weighted (T1w) images. In this work, we demonstrate that FIRST tends to produce inaccurate SGM segmentation results in the case of abnormal brain anatomy, such as present in atrophied brains, due to a poor spatial match of the subcortical structures with the training data in the MNI space as well as due to insufficient contrast of SGM structures on T1w images. Consequently, such deviations from the average brain anatomy may introduce analysis bias in clinical studies, which may not always be obvious and potentially remain unidentified. To improve the segmentation of subcortical nuclei, we propose to use FIRST in combination with a special Hybrid image Contrast (HC) and Non-Linear (nl) registration module (HC-nlFIRST), where the hybrid image contrast is derived from T1w images and magnetic susceptibility maps to create subcortical contrast that is similar to that in the Montreal Neurological Institute (MNI) template. In our approach, a nonlinear registration replaces FIRST's default linear registration, yielding a more accurate alignment of the input data to the MNI template. We evaluated our method on 82 subjects with particularly abnormal brain anatomy, selected from a database of >2000 clinical cases. Qualitative and quantitative analyses revealed that HC-nlFIRST provides improved segmentation compared to the default FIRST method. Copyright © 2017 Elsevier Inc. All rights reserved.

Simulating the Effect of Spectroscopic MRI as a Metric for Radiation Therapy Planning in Patients with Glioblastoma

PubMed Central

Cordova, J. Scott; Kandula, Shravan; Gurbani, Saumya; Zhong, Jim; Tejani, Mital; Kayode, Oluwatosin; Patel, Kirtesh; Prabhu, Roshan; Schreibmann, Eduard; Crocker, Ian; Holder, Chad A.; Shim, Hyunsuk; Shu, Hui-Kuo

2017-01-01

Due to glioblastoma’s infiltrative nature, an optimal radiation therapy (RT) plan requires targeting infiltration not identified by anatomical magnetic resonance imaging (MRI). Here, high-resolution, whole-brain spectroscopic MRI (sMRI) is used to describe tumor infiltration alongside anatomical MRI and simulate the degree to which it modifies RT target planning. In 11 patients with glioblastoma, data from preRT sMRI scans were processed to give high-resolution, whole-brain metabolite maps normalized by contralateral white matter. Maps depicting choline to N-Acetylaspartate (Cho/NAA) ratios were registered to contrast-enhanced T1-weighted RT planning MRI for each patient. Volumes depicting metabolic abnormalities (1.5−, 1.75−, and 2.0-fold increases in Cho/NAA ratios) were compared with conventional target volumes and contrast-enhancing tumor at recurrence. sMRI-modified RT plans were generated to evaluate target volume coverage and organ-at-risk dose constraints. Conventional clinical target volumes and Cho/NAA abnormalities identified significantly different regions of microscopic infiltration with substantial Cho/NAA abnormalities falling outside of the conventional 60 Gy isodose line (41.1, 22.2, and 12.7 cm3, respectively). Clinical target volumes using Cho/NAA thresholds exhibited significantly higher coverage of contrast enhancement at recurrence on average (92.4%, 90.5%, and 88.6%, respectively) than conventional plans (82.5%). sMRI-based plans targeting tumor infiltration met planning objectives in all cases with no significant change in target coverage. In 2 cases, the sMRI-modified plan exhibited better coverage of contrast-enhancing tumor at recurrence than the original plan. Integration of the high-resolution, whole-brain sMRI into RT planning is feasible, resulting in RT target volumes that can effectively target tumor infiltration while adhering to conventional constraints. PMID:28105468

Application of distributed optical fiber sensing technologies to the monitoring of leakage and abnormal disturbance of oil pipeline

NASA Astrophysics Data System (ADS)

Yang, Xiaojun; Zhu, Xiaofei; Deng, Chi; Li, Junyi; Liu, Cheng; Yu, Wenpeng; Luo, Hui

2017-10-01

To improve the level of management and monitoring of leakage and abnormal disturbance of long distance oil pipeline, the distributed optical fiber temperature and vibration sensing system is employed to test the feasibility for the healthy monitoring of a domestic oil pipeline. The simulating leakage and abnormal disturbance affairs of oil pipeline are performed in the experiment. It is demonstrated that the leakage and abnormal disturbance affairs of oil pipeline can be monitored and located accurately with the distributed optical fiber sensing system, which exhibits good performance in the sensitivity, reliability, operation and maintenance etc., and shows good market application prospect.

Renal damage detected by DMSA, despite normal renal ultrasound, in children with febrile UTI.

PubMed

Bush, N C; Keays, M; Adams, C; Mizener, K; Pritzker, K; Smith, W; Traylor, J; Villanueva, C; Snodgrass, W T

2015-06-01

2011 American Academy of Pediatrics guidelines recommended renal-bladder ultrasound (RBUS) as the only evaluation after febrile urinary tract infection (FUTI) in infants aged 2-24 months. We determined the sensitivity, specificity, and false negative rate of RBUS to identify DMSA-detected renal damage in this age group as well as in older children. Consecutive patients referred to pediatric urology with a history of FUTI underwent DMSA ≥ 3 months after FUTI. Abnormal RBUS was defined as: Society of Fetal Urology hydronephrosis grades I-IV; hydroureter ≥ 7 mm; renal scar defined as focal parenchymal thinning; and/or size discrepancy ≥ 1 cm between kidneys. Abnormal DMSA was presence of any focal uptake defects and/or split renal function < 44%. We calculated sensitivity, specificity, positive and negative predictive values, and false negative rates of RBUS compared to DMSA. 618 patients (79% female), median age 3.4 years, were referred for FUTIs. Of the 512 (83%) with normal RBUS, 99 (19%) had abnormal DMSA. Children with normal RBUS after their first FUTI had abnormal DMSA in 15/151 (10%) aged ≤ 24 months and 23/119 (19%) aged > 24 months. RBUS had poor sensitivity (34%) and low positive predictive value (47%) to identify patients with renal damage. 99/149 (66%) children with renal damage on DMSA had normal RBUS. After FUTI, 66% of children with reduced renal function and/or renal cortical defects found by DMSA scintigraphy had a normal RBUS. Since abnormal DMSA may correlate with increased risk for VUR, recurrent FUTI and renal damage, our data suggest RBUS alone will fail to detect a significant proportion of patients at risk. The data suggest that imaging after FUTI should include acute RBUS and delayed DMSA, reserving VCUG for patients with abnormal DMSA and/or recurrent FUTI. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Crowdsourcing as a novel technique for retinal fundus photography classification: analysis of images in the EPIC Norfolk cohort on behalf of the UK Biobank Eye and Vision Consortium.

PubMed

Mitry, Danny; Peto, Tunde; Hayat, Shabina; Morgan, James E; Khaw, Kay-Tee; Foster, Paul J

2013-01-01

Crowdsourcing is the process of outsourcing numerous tasks to many untrained individuals. Our aim was to assess the performance and repeatability of crowdsourcing for the classification of retinal fundus photography. One hundred retinal fundus photograph images with pre-determined disease criteria were selected by experts from a large cohort study. After reading brief instructions and an example classification, we requested that knowledge workers (KWs) from a crowdsourcing platform classified each image as normal or abnormal with grades of severity. Each image was classified 20 times by different KWs. Four study designs were examined to assess the effect of varying incentive and KW experience in classification accuracy. All study designs were conducted twice to examine repeatability. Performance was assessed by comparing the sensitivity, specificity and area under the receiver operating characteristic curve (AUC). Without restriction on eligible participants, two thousand classifications of 100 images were received in under 24 hours at minimal cost. In trial 1 all study designs had an AUC (95%CI) of 0.701(0.680-0.721) or greater for classification of normal/abnormal. In trial 1, the highest AUC (95%CI) for normal/abnormal classification was 0.757 (0.738-0.776) for KWs with moderate experience. Comparable results were observed in trial 2. In trial 1, between 64-86% of any abnormal image was correctly classified by over half of all KWs. In trial 2, this ranged between 74-97%. Sensitivity was ≥ 96% for normal versus severely abnormal detections across all trials. Sensitivity for normal versus mildly abnormal varied between 61-79% across trials. With minimal training, crowdsourcing represents an accurate, rapid and cost-effective method of retinal image analysis which demonstrates good repeatability. Larger studies with more comprehensive participant training are needed to explore the utility of this compelling technique in large scale medical image analysis.

Audit of paired anal cytology and histopathology outcomes in patients referred to a public sexual health clinic.

PubMed

Williams, Vincent M; Metcalf, Cecily; French, Martyn A; McCloskey, Jenny C

2010-09-01

The level of agreement between anal cytology and histopathology is not clear with only a few studies evaluating the reliability of anal specimen reporting. Australian data in relation to this are limited. The results of paired anal cytology and histopathology specimens received between 2002 and 2008 from patients who were referred within the sexual health clinic were retrieved from the anatomical pathology database. A total of 248 paired samples from 154 (21 females, 133 males) participants were extracted. Concurrent high risk human papilloma virus (hrHPV) DNA assay and HIV status for the study group were also collected. Data were tabulated according to reported grade of squamous abnormality based on the Bethesda system. Using the biopsy result as the gold standard the specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) for cytology were calculated and the association between grade of abnormality, HIV status and hrHPV infection estimated. Concordance between cytology and histology showed that in 204 (85%) paired samples both tests were categorised as abnormal (Kappa statistic 0.73, P = 0.013). The cytology result showed a sensitivity of 96%, specificity 14%, PPV 89% and NPV 31% when compared with histopathology. HrHPV assay was positive in 192 (80%) samples. High-grade squamous abnormalities were reported in biopsy specimens from 60% (n = 42/67) of HIV-positive subjects and 25% (n = 22/87) of HIV-negative subjects. HIV-positive individuals were more likely to be hrHPV positive, odds ratio (OR) 6.21 [95% confidence interval (CI) 2.69 to 14.34], when compared with HIV-negative subjects. Anal cytology is highly sensitive for the detection of abnormal squamous cells. While cytology has low specificity for predicting the grade of abnormality compared with biopsy outcome, its application as a screening method in asymptomatic at risk populations warrants further study.

Colour Doppler and microbubble contrast agent ultrasonography do not improve cancer detection rate in transrectal systematic prostate biopsy sampling.

PubMed

Taverna, Gianluigi; Morandi, Giovanni; Seveso, Mauro; Giusti, Guido; Benetti, Alessio; Colombo, Piergiuseppe; Minuti, Francesco; Grizzi, Fabio; Graziotti, Pierpaolo

2011-12-01

What's known on the subject? and What does the study add? Transrectal gray-scale ultrasonography guided prostate biopsy sampling is the method for diagnosing prostate cancer (PC) in patients with an increased prostate specific antigen level and/or abnormal digital rectal examination. Several imaging strategies have been proposed to optimize the diagnostic value of biopsy sampling, although at the first biopsy nearly 10-30% of PC still remains undiagnosed. This study compares the PC detection rate when employing Colour Doppler ultransongraphy with or without the injection of SonoVue™ microbubble contrast agent, versus the transrectal ultrasongraphy-guided systematic biopsy sampling. The limited accuracy, sensitivity, specificity and the additional cost of using the contrast agent do not justify its routine application in PC detection. • To compare prostate cancer (PC) detection rate employing colour Doppler ultrasonography with or without SonoVue™ contrast agent with transrectal ultrasonography-guided systematic biopsy sampling. • A total of 300 patients with negative digital rectal examination and transrectal grey-scale ultrasonography, with PSA values ranging between 2.5 and 9.9 ng/mL, were randomized into three groups: 100 patients (group A) underwent transrectal ultrasonography-guided systematic bioptic sampling; 100 patients (group B) underwent colour Doppler ultrasonography, and 100 patients (group C) underwent colour Doppler ultrasonography before and during the injection of SonoVue™. • Contrast-enhanced targeted biopsies were sampled into hypervascularized areas of peripheral, transitional, apical or anterior prostate zones. • All the patients included in Groups B and C underwent a further 13 systematic prostate biopsies. The cancer detection rate was calculated for each group. • In 88 (29.3%) patients a histological diagnosis of PC was made, whereas 22 (7.4%) patients were diagnosed with high-grade prostatic intraepithelial neoplasia or atypical small acinar proliferation. • No significant differences were found among the three groups for cancer detection rate (P= 0.329). • Additionally, low sensitivity, specificity and accuracy of colour Doppler with or without SonoVue™ contrast agent were found. • Prostate cancer detection rate does not significantly improve with the use of colour Doppler ultrasonography with or without SonoVue™. • Although no collateral effects have been highlighted, the combined use of colour Doppler ultrasonography and SonoVue™ determines adjunctive costs and increases the mean time for taking a single prostate biopsy. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

Impaired temporal contrast sensitivity in dyslexics is specific to retain-and-compare paradigms.

PubMed

Ben-Yehudah, G; Sackett, E; Malchi-Ginzberg, L; Ahissar, M

2001-07-01

Developmental dyslexia is a specific reading disability that affects 5-10% of the population. Recent studies have suggested that dyslexics may experience a deficit in the visual magnocellular pathway. The most extensively studied prediction deriving from this hypothesis is impaired contrast sensitivity to transient, low-luminance stimuli at low spatial frequencies. However, the findings are inconsistent across studies and even seemingly contradictory. In the present study, we administered several different paradigms for assessing temporal contrast sensitivity, and found both impaired and normal contrast sensitivity within the same group of dyslexic participants. Under sequential presentation, in a temporal forced choice paradigm, dyslexics showed impaired sensitivity to both drifting and flickering gratings. However, under simultaneous presentation, with a spatial forced choice paradigm, dyslexics' sensitivity did not differ from that of the controls. Within each paradigm, dyslexics' sensitivity was poorer at higher temporal frequencies, consistent with the magnocellular hypothesis. These results suggest that a basic perceptual impairment in dyslexics may be their limited ability to retain-and-compare perceptual traces across brief intervals.

Abnormalities in early visual processes are linked to hypersociability and atypical evaluation of facial trustworthiness: An ERP study with Williams syndrome.

PubMed

Shore, Danielle M; Ng, Rowena; Bellugi, Ursula; Mills, Debra L

2017-10-01

Accurate assessment of trustworthiness is fundamental to successful and adaptive social behavior. Initially, people assess trustworthiness from facial appearance alone. These assessments then inform critical approach or avoid decisions. Individuals with Williams syndrome (WS) exhibit a heightened social drive, especially toward strangers. This study investigated the temporal dynamics of facial trustworthiness evaluation in neurotypic adults (TD) and individuals with WS. We examined whether differences in neural activity during trustworthiness evaluation may explain increased approach motivation in WS compared to TD individuals. Event-related potentials were recorded while participants appraised faces previously rated as trustworthy or untrustworthy. TD participants showed increased sensitivity to untrustworthy faces within the first 65-90 ms, indexed by the negative-going rise of the P1 onset (oP1). The amplitude of the oP1 difference to untrustworthy minus trustworthy faces was correlated with lower approachability scores. In contrast, participants with WS showed increased N170 amplitudes to trustworthy faces. The N170 difference to low-high-trust faces was correlated with low approachability in TD and high approachability in WS. The findings suggest that hypersociability associated with WS may arise from abnormalities in the timing and organization of early visual brain activity during trustworthiness evaluation. More generally, the study provides support for the hypothesis that impairments in low-level perceptual processes can have a cascading effect on social cognition.

Further evidence for Clock△19 mice as a model for bipolar disorder mania using cross-species tests of exploration and sensorimotor gating

PubMed Central

van Enkhuizen, Jordy; Minassian, Arpi; Young, Jared W.

2013-01-01

Bipolar disorder (BD) is a pervasive neuropsychiatric disorder characterized by episodes of mania and depression. The switch between mania and depression may reflect seasonal changes and certainly can be affected by alterations in sleep and circadian control. The circadian locomotor output cycles kaput (CLOCK) protein is a key component of the cellular circadian clock. Mutation of the Clock gene encoding this protein in Clock△19 mutant mice leads to behavioral abnormalities reminiscent of BD mania. To date, however, these mice have not been assessed in behavioral paradigms that have cross-species translational validity. In the present studies of Clock△19 and wildtype (WT) littermate mice, we quantified exploratory behavior and sensorimotor gating, which are abnormal in BD manic patients. We also examined the saccharin preference of these mice and their circadian control in different photoperiods. Clock△19 mice exhibited behavioral alterations that are consistent with BD manic patients tested in comparable tasks, including hyperactivity, increased specific exploration, and reduced sensorimotor gating. Moreover, compared to WT mice, Clock△19 mice exhibited a greater preference for sweetened solutions and greater sensitivity to altered photoperiod. In contrast with BD manic patients however, Clock△19 mice exhibited more circumscribed movements during exploration. Future studies will extend the characterization of these mice in measures with cross-species translational relevance to human testing. PMID:23623885

Effect of binasal occlusion (BNO) on the visual-evoked potential (VEP) in mild traumatic brain injury (mTBI).

PubMed

Ciuffreda, Kenneth J; Yadav, Naveen K; Ludlam, Diana P

2013-01-01

The purpose of the experiment was to assess the effect of binasal occlusion (BNO) on the visually-evoked potential (VEP) in visually-normal (VN) individuals and in those with mild traumatic brain injury (mTBI) for whom BNO frequently reduces their primary symptoms related to abnormally-increased visual motion sensitivity (VMS). Subjects were comprised of asymptomatic VN adults (n = 10) and individuals with mTBI (n = 10) having the symptom of VMS. Conventional full-field VEP testing was employed under two conditions: without BNO and with opaque BNO which blocked regions on either side of the VEP test stimulus. Subjective impressions were also assessed. In VN, the mean VEP amplitude decreased significantly with BNO in all subjects. In contrast, in mTBI, the mean VEP amplitude increased significantly with BNO in all subjects. Latency was normal and unaffected in all cases. Repeat VEP testing in three subjects from each group revealed similar test-re-test findings. Visuomotor activities improved, with reduced symptoms, with BNO in the mTBI group. It is speculated that individuals with mTBI habitually attempt to suppress visual information in the near retinal periphery to reduce their abnormal VMS, with addition of the BNO negating the suppressive influence and thus producing a widespread disinhibition effect and resultant increase in VEP amplitude.

Pre-cancer risk assessment in habitual smokers from DIC images of oral exfoliative cells using active contour and SVM analysis.

PubMed

Dey, Susmita; Sarkar, Ripon; Chatterjee, Kabita; Datta, Pallab; Barui, Ananya; Maity, Santi P

2017-04-01

Habitual smokers are known to be at higher risk for developing oral cancer, which is increasing at an alarming rate globally. Conventionally, oral cancer is associated with high mortality rates, although recent reports show the improved survival outcomes by early diagnosis of disease. An effective prediction system which will enable to identify the probability of cancer development amongst the habitual smokers, is thus expected to benefit sizable number of populations. Present work describes a non-invasive, integrated method for early detection of cellular abnormalities based on analysis of different cyto-morphological features of exfoliative oral epithelial cells. Differential interference contrast (DIC) microscopy provides a potential optical tool as this mode provides a pseudo three dimensional (3-D) image with detailed morphological and textural features obtained from noninvasive, label free epithelial cells. For segmentation of DIC images, gradient vector flow snake model active contour process has been adopted. To evaluate cellular abnormalities amongst habitual smokers, the selected morphological and textural features of epithelial cells are compared with the non-smoker (-ve control group) group and clinically diagnosed pre-cancer patients (+ve control group) using support vector machine (SVM) classifier. Accuracy of the developed SVM based classification has been found to be 86% with 80% sensitivity and 89% specificity in classifying the features from the volunteers having smoking habit. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detection of early subclinical lung disease in children with cystic fibrosis by lung ventilation imaging with hyperpolarised gas MRI.

PubMed

Marshall, Helen; Horsley, Alex; Taylor, Chris J; Smith, Laurie; Hughes, David; Horn, Felix C; Swift, Andrew J; Parra-Robles, Juan; Hughes, Paul J; Norquay, Graham; Stewart, Neil J; Collier, Guilhem J; Teare, Dawn; Cunningham, Steve; Aldag, Ina; Wild, Jim M

2017-08-01

Hyperpolarised 3 He ventilation-MRI, anatomical lung MRI, lung clearance index (LCI), low-dose CT and spirometry were performed on 19 children (6-16 years) with clinically stable mild cystic fibrosis (CF) (FEV 1 >-1.96), and 10 controls. All controls had normal spirometry, MRI and LCI. Ventilation-MRI was the most sensitive method of detecting abnormalities, present in 89% of patients with CF, compared with CT abnormalities in 68%, LCI 47% and conventional MRI 22%. Ventilation defects were present in the absence of CT abnormalities and in patients with normal physiology, including LCI. Ventilation-MRI is thus feasible in young children, highly sensitive and provides additional information about lung structure-function relationships. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

In Vivo Detection of Choroidal Abnormalities Related to NF1: Feasibility and Comparison With Standard NIH Diagnostic Criteria in Pediatric Patients.

PubMed

Parrozzani, Raffaele; Clementi, Maurizio; Frizziero, Luisa; Miglionico, Giacomo; Perrini, Pierdavide; Cavarzeran, Fabiano; Kotsafti, Olympia; Comacchio, Francesco; Trevisson, Eva; Convento, Enrica; Fusetti, Stefano; Midena, Edoardo

2015-09-01

To evaluate the feasibility of near-infrared (NIR) imaging acquisition in a large sample of consecutive pediatric patients with neurofibromatosis type 1 (NF1), to evaluate the diagnostic performance of NF1-related choroidal abnormalities as a diagnostic criterion of the disease, and to compare this criterion with other standard National Institutes of Health (NIH) diagnostic criteria. A total of 140 consecutive pediatric patients (0-16 years old) affected by NF1 (at least two diagnostic criteria), 59 suspected (a single diagnostic criterion), and 42 healthy subjects (no diagnostic criterion) were consecutively included. Each patient underwent genetic, dermatologic, and ophthalmologic examination to evaluate the presence/absence of each NIH diagnostic criterion. The presence of NF1-related choroidal abnormalities was investigated using NIR confocal ophthalmoscopy. Two masked operators assessed Lisch nodules and NF1-related choroidal abnormalities. Neurofibromatosis type 1-related choroidal abnormalities were detected in 72 affected (60.5%) and 1 suspected (2.4%) child. No healthy subject had choroidal abnormalities. Feasibility rate of this sign was 82%. Sensitivity, specificity, and positive and negative predictive values of NF1-related choroidal abnormalities were 0.60, 0.97, 0.98, and 0.46, respectively. Compared with standard NIH criteria, the presence of NF1-related choroidal abnormalities was the third parameter for positive predictive value and the fourth for sensitivity, specificity, and negative predictive value. Compared with Lisch nodules, NF1-related choroidal abnormalities were characterized by higher specificity and positive predictive value. The interoperator agreement for Lisch nodules and NF1-related choroidal abnormalities was 0.67 (substantial) and 0.97 (almost perfect), respectively. The use of this sign moved one patient from the suspected to the affected group (0.5%). Neurofibromatosis type 1-related choroidal abnormalities represent a new diagnostic sign in NF1 children. The main advantage of this sign seems the theoretical possibility to anticipate NF1 diagnosis, whereas the main obstacle is the cooperation required by very young patients.

Genetic Influence on Contrast Sensitivity in Middle-Aged Male Twins

PubMed Central

Cronin-Golomb, Alice; Panizzon, Matthew S.; Lyons, Michael J.; Franz, Carol E.; Grant, Michael D.; Jacobson, Kristen C.; Eisen, Seth A.; Laudate, Thomas M.; Kremen, William S.

2007-01-01

Contrast sensitivity is strongly associated with daily functioning among older adults, but the genetic and environmental contributions to this ability are unknown. Using the classical twin method, we addressed this issue by examining contrast sensitivity at five spatial frequencies (1.5–18 cycles per degree) in 718 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). Heritability estimates were modest (14%–38%), whereas individual-specific environmental influences accounted for 62%–86% of the variance. Identifying the types of individual-specific events that impact contrast sensitivity may suggest interventions to modulate this ability and thereby improve overall quality of life as adults age. PMID:17604073

The Ideal Strategy for Cervical Cancer Screening in Japan: Result from the Fukui Cervical Cancer Screening Study.

PubMed

Kurokawa, T; Onuma, T; Shinagawa, A; Chino, Y; Kobayashi, M; Yoshida, Y

2018-05-16

The aims of the Fukui Cervical Cancer Screening (FCCS) study are to determine the frequency of women with high-risk HPV (hrHPV), whether HPV16 or HPV18 (HPV16/18), in the Japanese cancer screening population for the first time and to identify the best strategy for cervical cancer screening in Japan. This study enrolled 7,584 women ≥25 years of age who were undergoing routine screening. All women underwent liquid-based cytology and cobas HPV tests. Women with abnormal cytology, whether hrHPV positive or negative; women with hrHPV positivity with either normal or abnormal cytology; and women randomly selected from women with normal cytology and negative hrHPV negative were referred for colposcopy. The prevalences of hrHPV positivity and HPV16/18 positivity were 6.8% and 1.7%, respectively. The baseline data from the FCCS study showed that the combination of HPV tests and cytology was more sensitive than cytology with respect to the detection of intraepithelial neoplasia grade 2 or worse. However, the specificity (94.1%) of the co-testing strategy that required all women with abnormal cytology or hrHPV positivity to be referred for colposcopy was much lower than that (97.8%) of cytology. The sensitivity and specificity of the co-testing strategy that required only women with abnormal cytology or HPV16/18 positivity to undergo colposcopy were 85.5% and 97.0%, respectively. The baseline data from the FCCS study suggest that a cervical cancer screening strategy in which only women with abnormal cytology or HPV16/18 positivity undergo colposcopy offers a more balanced sensitivity and specificity than other strategies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Predicting motor development in very preterm infants at 12 months' corrected age: the role of qualitative magnetic resonance imaging and general movements assessments.

PubMed

Spittle, Alicia J; Boyd, Roslyn N; Inder, Terrie E; Doyle, Lex W

2009-02-01

The objective of this study was to compare the predictive value of qualitative MRI of brain structure at term and general movements assessments at 1 and 3 months' corrected age for motor outcome at 1 year's corrected age in very preterm infants. Eighty-six very preterm infants (<30 weeks' gestation) underwent MRI at term-equivalent age, were evaluated for white matter abnormality, and had general movements assessed at 1 and 3 months' corrected age. Motor outcome at 1 year's corrected age was evaluated with the Alberta Infant Motor Scale, the Neuro-Sensory Motor Development Assessment, and the diagnosis of cerebral palsy by the child's pediatrician. At 1 year of age, the Alberta Infant Motor Scale categorized 30 (35%) infants as suspicious/abnormal; the Neuro-Sensory Motor Development Assessment categorized 16 (18%) infants with mild-to-severe motor dysfunction, and 5 (6%) infants were classified with cerebral palsy. White matter abnormality at term and general movements at 1 and 3 months significantly correlated with Alberta Infant Motor Scale and Neuro-Sensory Motor Development Assessment scores at 1 year. White matter abnormality and general movements at 3 months were the only assessments that correlated with cerebral palsy. All assessments had 100% sensitivity in predicting cerebral palsy. White matter abnormality demonstrated the greatest accuracy in predicting combined motor outcomes, with excellent levels of specificity (>90%); however, the sensitivity was low. On the other hand, general movements assessments at 1 month had the highest sensitivity (>80%); however, the overall accuracy was relatively low. Neuroimaging (MRI) and functional (general movements) examinations have important complementary roles in predicting motor development of very preterm infants.

Multifocal and pattern-reversal visual evoked potentials vs. automated perimetry frequency-doubling technology matrix in optic neuritis

PubMed Central

Nebbioso, Marcella; Steigerwalt, Robert D; Pecori-Giraldi, Josè; Vingolo, Enzo M

2013-01-01

Background: To compare the usefulness of the traditional pattern-reversal Visual Evoked Potentials (VEP) with multifocal VEP (mfVEP) and Frequency-Doubling Technology (FDT) perimetry in the evaluation of the ocular abnormalities induced by acute or subacute optic neuritis (ON). Materials and Methods: The test results of 24 ON patients were compared with those obtained in 40 normal control subjects. MfVEP recordings were obtained by using an Optoelectronic Stimulator that extracts topographic VEP using a pseudorandom m-sequence stimulus. Receiver operator characteristic (ROC) curves were calculated to determine the sensitivity and specificity of abnormal values. Results: The frequency of the abnormal ocular findings differed in the ON patients according to the used technique. Reduced visual sensitivity was demonstrated in 12 eyes (54.5%) using FDT perimetry; 17 eyes (77.2%) showed decreased amplitude and/or an increase in the implicit time of the P1 wave in mfVEP and 20 eyes (90.9%) showed an abnormal decrease in the amplitude and/or an increase in the latency of the P100 peak at VEP examination. The areas under the ROC curves ranged from 0.743 to 0.935, with VEP having the largest areas. The VEP and mfVEP amplitudes and latencies yielded the greatest sensitivity and specificity. Conclusions: The mfVEP and the FDT perimetry can be used for the evaluation and monitoring of visual impairment in patients with ON. The most sensitive and practical diagnostic tool in patients with ON is, however, the traditional VEP. The mfVEP can be utilized in those cases with doubtful or negative VEP results. PMID:23412522

Morphological abnormalities during early-life development of the estuarine mummichog, Fundulus heteroclitus, as an indicator of androgenic and anti-androgenic endocrine disruption.

PubMed

Boudreau, Monica; Courtenay, Simon C; Maclatchy, Deborah L; Bérubé, Céline H; Hewitt, L Mark; Van Der Kraak, Glen J

2005-03-04

We tested the hypothesis that gross morphological abnormalities are a sensitive indicator of exposure to waterborne androgenic and anti-androgenic compounds during embryonic, larval and juvenile stages of development in the common estuarine killifish, the mummichog (Fundulus heteroclitus; Pisces: Cyprinodontidae). Static exposures with daily renewal were carried out with 10-100,000 ng/L of the androgen agonist, 17alpha-methyltestosterone (MT), or the androgen antagonist, cyproterone acetate (CA), for 60 days post-fertilization (PF) in duplicate exposures. Measured concentrations were 78.4-155.8% of nominal concentrations for MT and 13.5-168.1% for CA. No dose-related or consistent effects of MT or CA were observed before hatch. In 60 days PF juveniles, incidence of skeletal abnormalities (scoliosis, lordosis, head, facial and fin), soft tissue abnormality (anal swelling) and hemorrhaging were significantly increased by MT but only at high concentrations (> or =1000 ng/L). The 10,000 and 100,000 ng/L concentrations of MT produced a wider range of abnormalities than 1000ng/L. Over 90% of fish exposed to 10,000 or 100,000 ng/L were abnormal with an average of over 3.5 abnormalities per fish. CA did not increase the incidence of any type of abnormality. Survival of juveniles to the end of the exposure was reduced by MT at concentrations of 1000 ng/L and greater in the first experiment and at concentrations of 10,000 ng/L and greater in the second experiment. Juvenile length was reduced by high concentrations of MT (> or =10,000 ng/L) in the first experiment and by most concentrations in the second experiment. We conclude that morphological abnormalities in early-life stages of mummichogs are not a sensitive indicator of exposure to androgenic or anti-androgenic waterborne EDSs at environmentally relevant concentrations.

Automatic detection of anomalies in screening mammograms

PubMed Central

2013-01-01

Background Diagnostic performance in breast screening programs may be influenced by the prior probability of disease. Since breast cancer incidence is roughly half a percent in the general population there is a large probability that the screening exam will be normal. That factor may contribute to false negatives. Screening programs typically exhibit about 83% sensitivity and 91% specificity. This investigation was undertaken to determine if a system could be developed to pre-sort screening-images into normal and suspicious bins based on their likelihood to contain disease. Wavelets were investigated as a method to parse the image data, potentially removing confounding information. The development of a classification system based on features extracted from wavelet transformed mammograms is reported. Methods In the multi-step procedure images were processed using 2D discrete wavelet transforms to create a set of maps at different size scales. Next, statistical features were computed from each map, and a subset of these features was the input for a concerted-effort set of naïve Bayesian classifiers. The classifier network was constructed to calculate the probability that the parent mammography image contained an abnormality. The abnormalities were not identified, nor were they regionalized. The algorithm was tested on two publicly available databases: the Digital Database for Screening Mammography (DDSM) and the Mammographic Images Analysis Society’s database (MIAS). These databases contain radiologist-verified images and feature common abnormalities including: spiculations, masses, geometric deformations and fibroid tissues. Results The classifier-network designs tested achieved sensitivities and specificities sufficient to be potentially useful in a clinical setting. This first series of tests identified networks with 100% sensitivity and up to 79% specificity for abnormalities. This performance significantly exceeds the mean sensitivity reported in literature for the unaided human expert. Conclusions Classifiers based on wavelet-derived features proved to be highly sensitive to a range of pathologies, as a result Type II errors were nearly eliminated. Pre-sorting the images changed the prior probability in the sorted database from 37% to 74%. PMID:24330643

Guidelines to identify abnormalities after childhood urinary tract infections: a prospective audit

PubMed Central

Coulthard, Malcolm G; Lambert, Heather J; Vernon, Susan J; Hunter, Elizabeth W; Keir, Michael J

2014-01-01

Objective To compare the childhood urinary tract infection (UTI) guidelines from the Royal College of Physicians (RCP) in 1991 and from National Institute of Health and Care Excellence (NICE) (CG54) in 2007 by measuring their efficiency at detecting urinary tract abnormalities. Design Children with UTIs within the Newcastle Primary Care Trust (population 70 800 children) were referred and imaged according to the RCP guidelines during 2008, and these were compared to the activity that would have been undertaken if we had implemented the CG54 guidelines, including following them through 2011 to identify those with recurrent UTIs. Main outcome measures The numbers of children imaged, the imaging burden and efficiency, and urinary tract abnormalities detected by each guideline. Results Fewer children would have been imaged by CG54 than RCP (150 vs 427), but its sensitivity was lower, at 44% for detecting scarring, 10% for identifying vesicoureteric reflux and 40% for other abnormalities. Overall, it would have only detected one-quarter of the abnormal cases (8 vs 32) and would have missed five of nine children with scarring, including three with multiple lesions and one with renal impairment. Imposing an age restriction of <8 years to the RCP guidelines would reduce its screening rate by 20% and still detect 90% of the abnormalities. Interpretation The CG54 guidelines do not alter the imaging efficiency compared to the RCP guidelines, but they are considerably less sensitive. PMID:24436366

Time-resolved contrast-enhanced MR angiography of the thorax in adults with congenital heart disease.

PubMed

Mohrs, Oliver K; Petersen, Steffen E; Voigtlaender, Thomas; Peters, Jutta; Nowak, Bernd; Heinemann, Markus K; Kauczor, Hans-Ulrich

2006-10-01

The aim of this study was to evaluate the diagnostic value of time-resolved contrast-enhanced MR angiography in adults with congenital heart disease. Twenty patients with congenital heart disease (mean age, 38 +/- 14 years; range, 16-73 years) underwent contrast-enhanced turbo fast low-angle shot MR angiography. Thirty consecutive coronal 3D slabs with a frame rate of 1-second duration were acquired. The mask defined as the first data set was subtracted from subsequent images. Image quality was evaluated using a 5-point scale (from 1, not assessable, to 5, excellent image quality). Twelve diagnostic parameters yielded 1 point each in case of correct diagnosis (binary analysis into normal or abnormal) and were summarized into three categories: anatomy of the main thoracic vessels (maximum, 5 points), sequential cardiac anatomy (maximum, 5 points), and shunt detection (maximum, 2 points). The results were compared with a combined clinical reference comprising medical or surgical reports and other imaging studies. Diagnostic accuracies were calculated for each of the parameters as well as for the three categories. The mean image quality was 3.7 +/- 1.0. Using a binary approach, 220 (92%) of the 240 single diagnostic parameters could be analyzed. The percentage of maximum diagnostic points, the sensitivity, the specificity, and the positive and the negative predictive values were all 100% for the anatomy of the main thoracic vessels; 97%, 87%, 100%, 100%, and 96% for sequential cardiac anatomy; and 93%, 93%, 92%, 88%, and 96% for shunt detection. Time-resolved contrast-enhanced MR angiography provides, in one breath-hold, anatomic and qualitative functional information in adult patients with congenital heart disease. The high diagnostic accuracy allows the investigator to tailor subsequent specific MR sequences within the same session.

fMRI responses to words repeated in a congruous semantic context are abnormal in mild Alzheimer’s disease

PubMed Central

Olichney, John M.; Taylor, Jason R.; Chan, Shiaohui; Yang, Jin-Chen; Stringfellow, Andrew; Hillert, Dieter G.; Simmons, Amanda L.; Salmon, David P.; Iragui-Madoz, Vicente; Kutas, Marta

2010-01-01

Background We adapted an event-related brain potential word repetition paradigm, sensitive to early Alzheimer’s disease (AD), for functional MRI (fMRI). We hypothesized that AD would be associated with reduced differential response to new/old congruous words. Methods Fifteen mild AD patients (mean age = 72.9) and 15 normal elderly underwent 1.5T fMRI during a semantic category decision task. Results We found robust between-groups differences in BOLD response to congruous words. In controls, the New > Old contrast demonstrated larger responses in much of the left-hemisphere (including putative P600 generators: parahippocampal, cingulate, fusiform, perirhinal, middle temporal (MTG) and inferior frontal gyri (IFG)); the Old > New contrast showed modest activation, mainly in right parietal and prefrontal cortex. By contrast, there were relatively few regions of significant New > Old responses in AD patients, mainly in the right-hemisphere, and their Old > New contrast did not demonstrate a right-hemisphere predominance. Across subjects, the spatial extent of New > Old responses in left medial temporal lobe (MTL) correlated with subsequent recall and recognition (r’s ≥ 0.60). In controls, the magnitude of New - Old response in left MTL, fusiform, IFG, MTG, superior temporal and cingulate gyrus correlated with subsequent cued recall and/or recognition (0.51 ≤ r’s ≤ 0.78). Conclusions A distributed network of mostly left-hemisphere structures, which are putative P600 generators, appears important for successful verbal encoding (with New > Old responses to congruous words in normal elderly). This network appears dysfunctional in mild AD patients, as reflected in decreased word repetition effects particularly in left association cortex, paralimbic and MTL structures. PMID:20433856

Impairment of the glymphatic system after diabetes.

PubMed

Jiang, Quan; Zhang, Li; Ding, Guangliang; Davoodi-Bojd, Esmaeil; Li, Qingjiang; Li, Lian; Sadry, Neema; Nedergaard, Maiken; Chopp, Michael; Zhang, Zhenggang

2017-04-01

The glymphatic system has recently been shown to clear brain extracellular solutes and abnormalities in glymphatic clearance system may contribute to both initiation and progression of neurological diseases. Despite that diabetes is known as a risk factor for vascular diseases, little is known how diabetes affects the glymphatic system. The current study is the first investigation of the effect of diabetes on the glymphatic system and the link between alteration of glymphatic clearance and cognitive impairment in Type-2 diabetes mellitus rats. MRI analysis revealed that clearance of cerebrospinal fluid contrast agent Gd-DTPA from the interstitial space was slowed by a factor of three in the hippocampus of Type-2 diabetes mellitus rats compared to the non-DM rats and confirmed by florescence imaging analysis. Cognitive deficits detected by behavioral tests were highly and inversely correlated to the retention of Gd-DTPA contrast and fluorescent tracer in the hippocampus of Type-2 diabetes mellitus rats. Type-2 diabetes mellitus suppresses clearance of interstitial fluid in the hippocampus and hypothalamus, suggesting that an impairment of the glymphatic system contributes to Type-2 diabetes mellitus-induced cognitive deficits. Whole brain MRI provides a sensitive, non-invasive tool to quantitatively evaluate cerebrospinal fluid and interstitial fluid exchange in Type-2 diabetes mellitus and possibly in other neurological disorders, with potential clinical application.

Impairment of the glymphatic system after diabetes

PubMed Central

Zhang, Li; Ding, Guangliang; Davoodi-Bojd, Esmaeil; Li, Qingjiang; Li, Lian; Sadry, Neema; Nedergaard, Maiken; Chopp, Michael; Zhang, Zhenggang

2016-01-01

The glymphatic system has recently been shown to clear brain extracellular solutes and abnormalities in glymphatic clearance system may contribute to both initiation and progression of neurological diseases. Despite that diabetes is known as a risk factor for vascular diseases, little is known how diabetes affects the glymphatic system. The current study is the first investigation of the effect of diabetes on the glymphatic system and the link between alteration of glymphatic clearance and cognitive impairment in Type-2 diabetes mellitus rats. MRI analysis revealed that clearance of cerebrospinal fluid contrast agent Gd-DTPA from the interstitial space was slowed by a factor of three in the hippocampus of Type-2 diabetes mellitus rats compared to the non-DM rats and confirmed by florescence imaging analysis. Cognitive deficits detected by behavioral tests were highly and inversely correlated to the retention of Gd-DTPA contrast and fluorescent tracer in the hippocampus of Type-2 diabetes mellitus rats. Type-2 diabetes mellitus suppresses clearance of interstitial fluid in the hippocampus and hypothalamus, suggesting that an impairment of the glymphatic system contributes to Type-2 diabetes mellitus-induced cognitive deficits. Whole brain MRI provides a sensitive, non-invasive tool to quantitatively evaluate cerebrospinal fluid and interstitial fluid exchange in Type-2 diabetes mellitus and possibly in other neurological disorders, with potential clinical application. PMID:27306755

Brain structural correlates of reward sensitivity and impulsivity in adolescents with normal and excess weight.

PubMed

Moreno-López, Laura; Soriano-Mas, Carles; Delgado-Rico, Elena; Rio-Valle, Jacqueline S; Verdejo-García, Antonio

2012-01-01

Neuroscience evidence suggests that adolescent obesity is linked to brain dysfunctions associated with enhanced reward and somatosensory processing and reduced impulse control during food processing. Comparatively less is known about the role of more stable brain structural measures and their link to personality traits and neuropsychological factors on the presentation of adolescent obesity. Here we aimed to investigate regional brain anatomy in adolescents with excess weight vs. lean controls. We also aimed to contrast the associations between brain structure and personality and cognitive measures in both groups. Fifty-two adolescents (16 with normal weight and 36 with excess weight) were scanned using magnetic resonance imaging and completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), the UPPS-P scale, and the Stroop task. Voxel-based morphometry (VBM) was used to assess possible between-group differences in regional gray matter (GM) and to measure the putative differences in the way reward and punishment sensitivity, impulsivity and inhibitory control relate to regional GM volumes, which were analyzed using both region of interest (ROI) and whole brain analyses. The ROIs included areas involved in reward/somatosensory processing (striatum, somatosensory cortices) and motivation/impulse control (hippocampus, prefrontal cortex). Excess weight adolescents showed increased GM volume in the right hippocampus. Voxel-wise volumes of the second somatosensory cortex (SII) were correlated with reward sensitivity and positive urgency in lean controls, but this association was missed in excess weight adolescents. Moreover, Stroop performance correlated with dorsolateral prefrontal cortex volumes in controls but not in excess weight adolescents. Adolescents with excess weight have structural abnormalities in brain regions associated with somatosensory processing and motivation.

Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor

PubMed Central

Hoi, Pui Man; Hiley, C Robin

2006-01-01

Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2±0.2 μM, Rmax=99.1±3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3±1.6 μM, Rmax=59.2±7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50 nM) (EC50=2.1±0.2 μM, Rmax=58.4±1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 μM for 30 min) shifted the oleamide concentration–response curve ∼30-fold to the right (n=7; P<0.01). Pertussis toxin (400 ng ml−1 for 2 h) caused a two-fold shift in the response curve (EC50=2.2±0.4 μM, Rmax=66.8±4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 μM) significantly inhibited relaxation induced by oleamide (EC50=3.5±0.3 μM, Rmax=75.1±1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 μM), nor the CB2 antagonist, SR144528 (1 μM), had significant effects. O-1918 (10 μM), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KCa) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KCa and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site. PMID:16415907

Uniform apparent contrast noise: A picture of the noise of the visual contrast detection system

NASA Technical Reports Server (NTRS)

Ahumada, A. J., Jr.; Watson, A. B.

1984-01-01

A picture which is a sample of random contrast noise is generated. The noise amplitude spectrum in each region of the picture is inversely proportional to spatial frequency contrast sensitivity for that region, assuming the observer fixates the center of the picture and is the appropriate distance from it. In this case, the picture appears to have approximately the same contrast everywhere. To the extent that contrast detection thresholds are determined by visual system noise, this picture can be regarded as a picture of the noise of that system. There is evidence that, at different eccentricities, contrast sensitivity functions differ only by a magnification factor. The picture was generated by filtering a sample of white noise with a filter whose frequency response is inversely proportional to foveal contrast sensitivity. It was then stretched by a space-varying magnification function. The picture summmarizes a noise linear model of detection and discrimination of contrast signals by referring the model noise to the input picture domain.

Machine learning based brain tumour segmentation on limited data using local texture and abnormality.

PubMed

Bonte, Stijn; Goethals, Ingeborg; Van Holen, Roel

2018-05-07

Brain tumour segmentation in medical images is a very challenging task due to the large variety in tumour shape, position, appearance, scanning modalities and scanning parameters. Most existing segmentation algorithms use information from four different MRI-sequences, but since this is often not available, there is need for a method able to delineate the different tumour tissues based on a minimal amount of data. We present a novel approach using a Random Forests model combining voxelwise texture and abnormality features on a contrast-enhanced T1 and FLAIR MRI. We transform the two scans into 275 feature maps. A random forest model next calculates the probability to belong to 4 tumour classes or 5 normal classes. Afterwards, a dedicated voxel clustering algorithm provides the final tumour segmentation. We trained our method on the BraTS 2013 database and validated it on the larger BraTS 2017 dataset. We achieve median Dice scores of 40.9% (low-grade glioma) and 75.0% (high-grade glioma) to delineate the active tumour, and 68.4%/80.1% for the total abnormal region including edema. Our fully automated brain tumour segmentation algorithm is able to delineate contrast enhancing tissue and oedema with high accuracy based only on post-contrast T1-weighted and FLAIR MRI, whereas for non-enhancing tumour tissue and necrosis only moderate results are obtained. This makes the method especially suitable for high-grade glioma. Copyright © 2018 Elsevier Ltd. All rights reserved.

In vivo imaging of pulmonary nodule and vasculature using endoscopic co-registered optical coherence tomography and autofluorescence imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Pahlevaninezhad, Hamid; Lee, Anthony; Hohert, Geoffrey; Schwartz, Carely; Shaipanich, Tawimas; Ritchie, Alexander J.; Zhang, Wei; MacAulay, Calum E.; Lam, Stephen; Lane, Pierre M.

2016-03-01

Peripheral lung nodules found by CT-scans are difficult to localize and biopsy bronchoscopically particularly for those ≤ 2 cm in diameter. In this work, we present the results of endoscopic co-registered optical coherence tomography and autofluorescence imaging (OCT-AFI) of normal and abnormal peripheral airways from 40 patients using 0.9 mm diameter fiber optic rotary pullback catheter. Optical coherence tomography (OCT) can visualize detailed airway morphology endoscopically in the lung periphery. Autofluorescence imaging (AFI) can visualize fluorescing tissue components such as collagen and elastin, enabling the detection of airway lesions with high sensitivity. Results indicate that AFI of abnormal airways is different from that of normal airways, suggesting that AFI can provide a sensitive visual presentation for rapidly identifying possible sites of pulmonary nodules. AFI can also rapidly visualize in vivo vascular networks using fast scanning parameters resulting in vascular-sensitive imaging with less breathing/cardiac motion artifacts compared to Doppler OCT imaging. It is known that tumor vasculature is structurally and functionally different from normal vessels. Thus, AFI can be potentially used for differentiating normal and abnormal lung vasculature for studying vascular remodeling.

Screening for Chronic Obstructive Pulmonary Disease (COPD) in an Urban HIV Clinic: A Pilot Study

PubMed Central

Kaner, Robert J.; Glesby, Marshall J.

2015-01-01

Abstract Increased smoking and a detrimental response to tobacco smoke in the lungs of HIV/AIDS patients result in an increased risk for COPD. We aimed to determine the predictive value of a COPD screening strategy validated in the general population and to identify HIV-related factors associated with decreased lung function. Subjects at least 35 years of age at an HIV clinic in New York City completed a COPD screening questionnaire and peak flow measurement. Those with abnormal results and a random one-third of normal screens had spirometry. 235 individuals were included and 89 completed spirometry. Eleven (12%) had undiagnosed airway obstruction and 5 had COPD. A combination of a positive questionnaire and abnormal peak flow yielded a sensitivity of 20% (specificity 93%) for detection of COPD. Peak flow alone had a sensitivity of 80% (specificity 80%). Abnormal peak flow was associated with an AIDS diagnosis (p=0.04), lower nadir (p=0.001), and current CD4 counts (p=0.001). Nadir CD4 remained associated in multivariate analysis (p=0.05). Decreased FEV1 (<80% predicted) was associated with lower CD4 count nadir (p=0.04) and detectable current HIV viral load (p=0.01) in multivariate analysis. Questionnaire and peak flow together had low sensitivity, but abnormal peak flow shows potential as a screening tool for COPD in HIV/AIDS. These data suggest that lung function may be influenced by HIV-related factors. PMID:25723842

Dynamic diaschisis: anatomically remote and context-sensitive human brain lesions.

PubMed

Price, C J; Warburton, E A; Moore, C J; Frackowiak, R S; Friston, K J

2001-05-15

Functional neuroimaging was used to investigate how lesions to the Broca's area impair neuronal responses in remote undamaged cortical regions. Four patients with speech output problems, but relatively preserved comprehension, were scanned while viewing words relative to consonant letter strings. In normal subjects, this results in left lateralized activation in the posterior inferior frontal, middle temporal, and posterior inferior temporal cortices. Each patient activated normally in the middle temporal region but abnormally in the damaged posterior inferior frontal cortex and the undamaged posterior inferior temporal cortex. In the damaged frontal region, activity was insensitive to the presence of words but in the undamaged posterior inferior temporal region, activity decreased in the presence of words rather than increasing as it did in the normal individuals. The reversal of responses in the left posterior inferior temporal region illustrate the context-sensitive nature of the abnormality and that failure to activate the left posterior temporal region could not simply be accounted for by insufficient demands on the underlying function. We propose that, in normal individuals, visual word presentation changes the effective connectivity among reading areas and, in patients, posterior temporal responses are abnormal when they depend upon inputs from the damaged inferior frontal cortex. Our results serve to introduce the concept of dynamic diaschisis; the anatomically remote and context-sensitive effects of focal brain lesions. Dynamic diaschisis reveals abnormalities of functional integration that may have profound implications for neuropsychological inference, functional anatomy and, vicariously, cognitive rehabilitation.

Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography.

PubMed

Owen, Joshua M; Gaba, Ron Charles

2016-01-01

The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or <90 cm/s) TIPS velocity, significant velocity rise/fall (>50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance.

Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography

PubMed Central

Owen, Joshua M; Gaba, Ron Charles

2016-01-01

Objectives: The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or <90 cm/s) TIPS velocity, significant velocity rise/fall (>50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Results: Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Conclusion: Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance. PMID:27563495

Pulse oximetry in the evaluation of peripheral vascular disease.

PubMed

Jawahar, D; Rachamalla, H R; Rafalowski, A; Ilkhani, R; Bharathan, T; Anandarao, N

1997-08-01

The role of pulse oximetry in the evaluation of peripheral vascular disease (PVD) was investigated. In addition, the value of elevating the limb to improve the sensitivity of detection of PVD by the pulse oximeter was also determined. Pulse oximetry reading in the toes were obtained in 40 young, healthy volunteers and in 40 randomly selected patients referred to the vascular investigation laboratory over a period of two months. All 40 healthy volunteers had normal pulse oximetry readings. Normal pulse oximetry reading in the toes was defined as > 95% O2 Sat and +/-2 of finger pulse oximetry reading. In all 40 patients, pulse oximetry readings were either normal or not detected at all. Since there was no gradation in decrease in the pulse oximetry reading with severity of disease or with elevation of the patient's lower extremity, an absent or no reading was considered as an abnormal result from the test. The frequency of abnormal pulse oximetry readings increased significantly in groups with abnormal ankle-brachial pressure index (ABPI) and also varied significantly with elevation of the patients' lower limbs. In patients with no PVD detected by Doppler (ABPI > 0.9), pulse oximetry readings were normal in all. However, in patients with moderate PVD (ABPI, 0.5-0.9), 84% of the patients' lower limbs had normal pulse oximetry readings and 16% had an abnormal reading at baseline level (flat). An additional 12% of the lower limbs in this group had an abnormal reading on elevation of the limb to 12 inches. In patients with severe PVD (ABPI < 0.5), 54% of the patients' lower limbs had an abnormal reading at baseline and an additional 23% had an abnormal reading at elevation of the limb to 12 inches. In conclusion, pulse oximetry was not a sensitive test for detecting early PVD.

Evaluation of a Myopic Normative Database for Analysis of Retinal Nerve Fiber Layer Thickness.

PubMed

Biswas, Sayantan; Lin, Chen; Leung, Christopher K S

2016-09-01

Analysis of retinal nerve fiber layer (RNFL) abnormalities with optical coherence tomography in eyes with high myopia has been complicated by high rates of false-positive errors. An understanding of whether the application of a myopic normative database can improve the specificity for detection of RNFL abnormalities in eyes with high myopia is relevant. To evaluate the diagnostic performance of a myopic normative database for detection of RNFL abnormalities in eyes with high myopia (spherical equivalent, -6.0 diopters [D] or less). In this cross-sectional study, 180 eyes with high myopia (mean [SD] spherical equivalent, -8.0 [1.8] D) from 180 healthy individuals were included in the myopic normative database. Another 46 eyes with high myopia from healthy individuals (mean [SD] spherical equivalent, -8.1 [1.8] D) and 74 eyes from patients with high myopia and glaucoma (mean [SD] spherical equivalent, -8.3 [1.9] D) were included for evaluation of specificity and sensitivity. The 95th and 99th percentiles of the mean and clock-hour circumpapillary RNFL thicknesses and the individual superpixel thicknesses of the RNFL thickness map measured by spectral-domain optical coherence tomography were calculated from the 180 eyes with high myopia. Participants were recruited from January 2, 2013, to December 30, 2015. The following 6 criteria of RNFL abnormalities were examined: (1) mean circumpapillary RNFL thickness below the lower 95th or (2) the lower 99th percentile; (3) one clock-hour or more for RNFL thickness below the lower 95th or (4) the lower 99th percentile; and (5) twenty contiguous superpixels or more of RNFL thickness in the RNFL thickness map below the lower 95th or (6) the lower 99th percentile. Specificities and sensitivities for detection of RNFL abnormalities. Of the 46 healthy eyes and 74 eyes with glaucoma studied (from 39 men and 38 women), the myopic normative database showed a higher specificity (63.0%-100%) than did the built-in normative database of the optical coherence tomography instrument (8.7%-87.0%) for detection of RNFL abnormalities across all the criteria examined (differences in specificities between 13.0% [95% CI, 1.1%-24.9%; P = .01] and 54.3% [95% CI, 37.8%-70.9%; P < .001]) except for the criterion of mean RNFL thickness below the lower 99th percentile, in which both normative databases had the same specificities (100%) but the myopic normative database exhibited a higher sensitivity (71.6% vs 86.5%; difference in sensitivities, 14.9% [95% CI, 4.6%-25.1%; P = .002]). The application of a myopic normative database improved the specificity without compromising the sensitivity compared with the optical coherence tomography instrument's built-in normative database for detection of RNFL abnormalities in eyes with high myopia. Inclusion of myopic normative databases should be considered in optical coherence tomography instruments.

Neural mechanisms of oculomotor abnormalities in the infantile strabismus syndrome.

PubMed

Walton, Mark M G; Pallus, Adam; Fleuriet, Jérome; Mustari, Michael J; Tarczy-Hornoch, Kristina

2017-07-01

Infantile strabismus is characterized by numerous visual and oculomotor abnormalities. Recently nonhuman primate models of infantile strabismus have been established, with characteristics that closely match those observed in human patients. This has made it possible to study the neural basis for visual and oculomotor symptoms in infantile strabismus. In this review, we consider the available evidence for neural abnormalities in structures related to oculomotor pathways ranging from visual cortex to oculomotor nuclei. These studies provide compelling evidence that a disturbance of binocular vision during a sensitive period early in life, whatever the cause, results in a cascade of abnormalities through numerous brain areas involved in visual functions and eye movements. Copyright © 2017 the American Physiological Society.

Assessment of contrast sensitivity by Spaeth Richman Contrast Sensitivity Test and Pelli Robson Chart Test in patients with varying severity of glaucoma.

PubMed

Thakur, Sahil; Ichhpujani, Parul; Kumar, Suresh; Kaur, Ravneet; Sood, Sunandan

2018-05-14

This study was designed to assess the efficacy, reliability and repeatability of SPARCS (Spaeth Richman Contrast Sensitivity Test) as compared to the conventional Pelli Robson Chart Test for the assessment of contrast sensitivity in patients with glaucoma. We evaluated 135 eyes of 135 patients who were age and sex matched into three groups (controls, disc suspects and glaucoma) of 45 patients each. The glaucoma subgroup was further divided into subgroups of mild, moderate and severe based on the visual field damage. There was a strong positive correlation between Pelli Robson scores and SPARCS scores (S = 0.807, P < 0.001). Intraclass correlation coefficient (ICC) for Pelli Robson Test was 0.952 and 0.988 for SPARCS. The coefficient of repeatability (COR) for mean SPARCS was 5.65%, while COR of Pelli Robson Test was 12.44%. SPARCS was found to have better repeatability than Pelli Robson Test based on COR values. Pelli Robson score had a sensitivity of 80% and a specificity of 65.6% for detecting glaucoma patients as compared to 84.4% and 70%, respectively, for SPARCS scores. SPARCS is a better alternative to conventional Pelli Robson Chart Test for assessment of contrast sensitivity in patients with glaucoma. Being independent of the effects of literacy and educational status, it offers a universal way to measure contrast sensitivity. It can also be reliably used in patients with varying severity of glaucoma.

The sensitivity and specificity of the neurological examination in polyneuropathy patients with clinical and electrophysiological correlations

PubMed Central

Alabdali, Majed; Alsulaiman, Abdulla; Albulaihe, Hana; Breiner, Ari; Katzberg, Hans D.; Aljaafari, Danah; Lovblom, Leif E.; Bril, Vera

2017-01-01

Introduction Polyneuropathy is one of the most prevalent neurologic disorders. Although several studies explored the role of the neurological examination in polyneuropathy, they were mostly restricted to specific subgroups of patients and have not correlated examination findings with symptoms and electrophysiological results. Objectives To explore the sensitivity and specificity of different neurological examination components in patients with diverse etiologies for polyneuropathy, find the most sensitive combination of examination components for polyneuropathy detection, and correlate examination findings with symptoms and electrophysiological results. Methods Patients with polyneuropathy attending the neuromuscular clinic from 01/2013 to 09/2015 were evaluated. Inclusion criteria included symptomatic polyneuropathy, which was confirmed by electrophysiological studies. 47 subjects with no symptoms or electrophysiological findings suggestive for polyneuropathy, served as controls. Results The total cohort included 312 polyneuropathy patients, with a mean age of 60±14 years. Abnormal examination was found in 95%, most commonly sensory findings (86%). The most common abnormal examination components were impaired ankle reflexes (74%), vibration (73%), and pinprick (72%) sensation. Combining ankle reflex examination with vibration or pinprick perception had the highest sensitivity, of 88%. The specificities of individual examination component were generally high, excluding ankle reflexes (62%), and vibration perception (77%). Abnormal examination findings were correlated with symptomatic weakness and worse electrophysiological parameters. Conclusion The neurological examination is a valid, sensitive and specific tool for diagnosing polyneuropathy, and findings correlate with polyneuropathy severity. Ankle reflex examination combined with either vibration or pinprick sensory testing is the most sensitive combination for diagnosing polyneuropathy, and should be considered minimal essential components of the physical examination in patients with suspected polyneuropathy. PMID:28249029

Evaluation of transcatheter arterial embolization therapy on hepatocellular carcinomas using contrast-enhanced harmonic power Doppler sonography: comparison with CT, power Doppler sonography, and dynamic MRI.

PubMed

Shima, Toshihide; Mizuno, Masayuki; Otsuji, Hideaki; Mizuno, Chiemi; Obata, Hirozumi; Park, Hyohun; Nakajo, Shinobu; Okanoue, Takeshi

2005-09-01

The aim of this study was to assess and compare the sensitivity of power Doppler sonography, contrast-enhanced sonography, plain computed tomography (CT), and dynamic magnetic resonance imaging (MRI) for detecting hepatocellular carcinoma (HCC) nodules incompletely treated with transcatheter arterial embolization (TAE). A total of 63 unresectable HCC nodules were examined in this study. The HCCs were treated with TAE. All patients underwent plain CT, power Doppler sonography, contrast-enhanced harmonic power Doppler sonography, and dynamic MRI 1 week after TAE. The sensitivity of each modality to incompletely treated HCC nodules was compared. Detection of the residual viable HCC on angiography or tumor biopsy was regarded as the gold standard for the diagnosis of incomplete treatment. Twenty-four nodules (38%) were diagnosed as incompletely treated. The sensitivities of plain CT, power Doppler sonography, contrast-enhanced harmonic power Doppler sonography, and dynamic MRI to these incompletely treated nodules were 42% (10/24), 46% (11/24), 88% (21/24), and 79% (19/24), respectively. Eighty percent (19 nodules) of the 24 incompletely treated nodules were located within a depth of less than 8 cm. The sensitivities of plain CT, power Doppler sonography, contrast-enhanced harmonic power Doppler sonography, and dynamic MRI to these superficial incompletely treated nodules were 37% (7/19), 53% (10/19), 100% (19/19), and 74% (14/19), respectively. In contrast, the sensitivities of each modality to deeply located nodules were 60% (3/5), 20% (1/5), 40% (2/5), and 100% (5/5), respectively. Plain CT and power Doppler sonography had a low sensitivity to HCC nodules incompletely treated with TAE. Except for those that were deeply located, contrast-enhanced harmonic sonography showed the highest sensitivity in detecting incompletely treated HCC nodules.

Effects of Retinal Morphology on Contrast Sensitivity and Reading Ability in Neovascular Age-Related Macular Degeneration

PubMed Central

Keane, Pearse A.; Patel, Praveen J.; Ouyang, Yanling; Chen, Fred K.; Ikeji, Felicia; Walsh, Alexander C.; Tufail, Adnan

2010-01-01

Purpose. To investigate the effect of changes in retinal morphology on contrast sensitivity and reading ability in patients with neovascular age-related macular degeneration (AMD) in the Avastin (bevacizumab; Genentech, South San Francisco, CA) for choroidal neovascularization (ABC) Trial. Methods. Contrast sensitivity obtained with Pelli-Robson charts, reading ability assessed with Minnesota Reading charts, and Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) obtained by protocol refraction, were recorded. Raw Stratus optical coherence tomography (OCT; Carl Zeiss Meditec, Inc., Dublin, CA) images were analyzed with the publicly available software OCTOR, which allows precise delineation of any retinal compartment of interest. Thickness and volume were calculated for neurosensory retina, subretinal fluid (SRF), subretinal tissue, and pigment epithelium detachment, and the resulting measurements were correlated with each visual function parameter. Results. One hundred twenty-two patients with newly diagnosed neovascular AMD and enrolled in the ABC Trial, were evaluated. Increased subretinal tissue volume correlated with decreased contrast sensitivity (Pearson's correlation coefficient, r = −0.4944, P = 0.001). A modest correlation was detected between SRF volume and contrast sensitivity (r = −0.2562, P = 0.004). Increased retinal thickness at the foveal center also correlated with decreased visual function (ETDRS VA: r = −0.4530, P < 0.001). Conclusions. The strongest correlation detected between the functional parameters assessed and any of the OCT-derived morphologic parameters was that between decreased contrast sensitivity and increased subretinal tissue. In the future, assessment of contrast sensitivity and reading ability, in combination with quantitative subanalysis of retinal compartments, may lead to the identification of parameters relevant to functional improvement and ultimate prognosis in patients with newly diagnosed neovascular AMD (www.controlled-trials.com number, ISRCTN83325075). PMID:20554607

A contrast-sensitive channelized-Hotelling observer to predict human performance in a detection task using lumpy backgrounds and Gaussian signals

NASA Astrophysics Data System (ADS)

Park, Subok; Badano, Aldo; Gallas, Brandon D.; Myers, Kyle J.

2007-03-01

Previously, a non-prewhitening matched filter (NPWMF) incorporating a model for the contrast sensitivity of the human visual system was introduced for modeling human performance in detection tasks with different viewing angles and white-noise backgrounds by Badano et al. But NPWMF observers do not perform well detection tasks involving complex backgrounds since they do not account for random backgrounds. A channelized-Hotelling observer (CHO) using difference-of-Gaussians (DOG) channels has been shown to track human performance well in detection tasks using lumpy backgrounds. In this work, a CHO with DOG channels, incorporating the model of the human contrast sensitivity, was developed similarly. We call this new observer a contrast-sensitive CHO (CS-CHO). The Barten model was the basis of our human contrast sensitivity model. A scalar was multiplied to the Barten model and varied to control the thresholding effect of the contrast sensitivity on luminance-valued images and hence the performance-prediction ability of the CS-CHO. The performance of the CS-CHO was compared to the average human performance from the psychophysical study by Park et al., where the task was to detect a known Gaussian signal in non-Gaussian distributed lumpy backgrounds. Six different signal-intensity values were used in this study. We chose the free parameter of our model to match the mean human performance in the detection experiment at the strongest signal intensity. Then we compared the model to the human at five different signal-intensity values in order to see if the performance of the CS-CHO matched human performance. Our results indicate that the CS-CHO with the chosen scalar for the contrast sensitivity predicts human performance closely as a function of signal intensity.

Postoperative ocular higher-order aberrations and contrast sensitivity: femtosecond lenticule extraction versus pseudo small-incision lenticule extraction.

PubMed

Tan, Deborah K L; Tay, Wan Ting; Chan, Cordelia; Tan, Donald T H; Mehta, Jodhbir S

2015-03-01

To evaluate and compare changes in contrast sensitivity and ocular higher-order aberrations (HOAs) after femtosecond lenticule extraction (FLEx) and pseudo small-incision lenticule extraction (SMILE). Singapore National Eye Centre, Singapore. Retrospective case series. Patients had femtosecond lenticule extraction (Group 1) or pseudo small-incision lenticule extraction (Group 2) between March 2010 and December 2011. The main outcome measures were manifest refraction, HOAs, and contrast sensitivity 1, 3, 6, and 12 months postoperatively. Fifty-two consecutive patients (102 eyes) were recruited, 21 patients (42 eyes) in Group 1 and the 31 patients (60 eyes) in Group 2. The uncorrected and corrected distance visual acuities were significantly better in Group 2 than in Group 1 at 12 months (P = .032). There was no significant increase in 3rd- or 4th-order aberrations at 1 year and no significant difference between the 2 groups preoperatively or postoperatively. At 1 year, there was a significant increase in mesopic contrast sensitivity in Group 2 at 1.5 cycles per degree (cpd) (P = .008) that was not found in Group 1, and photopic contrast sensitivity at 6.0 cpd was higher in Group 2 (P = .027). These results indicate that refractive lenticule extraction is safe and effective with no significant induction of HOAs or deterioration in contrast sensitivity at 1 year. Induction of HOAs was not significantly different between both variants of refractive lenticule extraction. However, there was significant improvement in photopic contrast sensitivity after pseudo small-incision lenticule extraction, which persisted through 1 year. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Cognition and behavior in pre-pubertal children with Prader-Willi syndrome and associations with sleep-related breathing disorders.

PubMed

Festen, Dederieke A M; Wevers, Maaike; de Weerd, Al W; van den Bossche, Renilde A S; Duivenvoorden, Hugo J; Hokken-Koelega, Anita C S

2008-12-01

Prader-Willi syndrome (PWS) is characterized by hypotonia, hypogonadism, obesity, and short stature. Neurobehavioral abnormalities, cognitive impairment, and sleep-related breathing disorders (SRBD) are common. In the general population associations between neurobehavioral and cognitive abnormalities and SRBD have been found. We investigated cognition, behavior, and SRBD in children with PWS. Thirty-one pre-pubertal PWS children were evaluated (5 with paternal deletion, 14 with maternal disomy, 4 with imprinting-center mutation, and in 8 the defect was not specified). Cognition was assessed by Wechsler scale subtests, and behavior by parent-questionnaires. Polysomnography was performed. Cognition, behavior, and associations with SRBD were evaluated. All cognitive subtests were significantly below O SDS, with the lowest median (interquartile range) scores for the Block design subtest (-2.7 SDS (-3.0 to -0.3)). In 60%, verbal subtests were less affected than performance subtests. Parents reported problem behavior related to "emotions/behavior not adapted to the social situation" and "insensitivity to social information." All children had SRBD, with an Apnea Hypopnea Index of 4.1/hr (2.6-7.9). One performance subtest score was significantly higher in children with better sleep efficiency, and daytime sleepiness was associated with more autistic-like social impairment. In contrast to our expectations, behavior was worse in children with better sleep-related breathing. In pre-pubertal PWS children, cognition is impaired. Neurobehavioral abnormalities are common, particularly autistic-like social impairment. Sleep efficiency was associated with better performance on one of the performance subtests, and neurobehavioral abnormalities were associated with daytime sleepiness. In contrast, we could not confirm a positive association of neurobehavioral abnormalities with SRBD in PWS. Copyright (c) 2008 Wiley-Liss, Inc.

The effect of transcranial direct current stimulation on contrast sensitivity and visual evoked potential amplitude in adults with amblyopia

PubMed Central

Ding, Zhaofeng; Li, Jinrong; Spiegel, Daniel P.; Chen, Zidong; Chan, Lily; Luo, Guangwei; Yuan, Junpeng; Deng, Daming; Yu, Minbin; Thompson, Benjamin

2016-01-01

Amblyopia is a neurodevelopmental disorder of vision that occurs when the visual cortex receives decorrelated inputs from the two eyes during an early critical period of development. Amblyopic eyes are subject to suppression from the fellow eye, generate weaker visual evoked potentials (VEPs) than fellow eyes and have multiple visual deficits including impairments in visual acuity and contrast sensitivity. Primate models and human psychophysics indicate that stronger suppression is associated with greater deficits in amblyopic eye contrast sensitivity and visual acuity. We tested whether transcranial direct current stimulation (tDCS) of the visual cortex would modulate VEP amplitude and contrast sensitivity in adults with amblyopia. tDCS can transiently alter cortical excitability and may influence suppressive neural interactions. Twenty-one patients with amblyopia and twenty-seven controls completed separate sessions of anodal (a-), cathodal (c-) and sham (s-) visual cortex tDCS. A-tDCS transiently and significantly increased VEP amplitudes for amblyopic, fellow and control eyes and contrast sensitivity for amblyopic and control eyes. C-tDCS decreased VEP amplitude and contrast sensitivity and s-tDCS had no effect. These results suggest that tDCS can modulate visual cortex responses to information from adult amblyopic eyes and provide a foundation for future clinical studies of tDCS in adults with amblyopia. PMID:26763954

The effect of transcranial direct current stimulation on contrast sensitivity and visual evoked potential amplitude in adults with amblyopia.

PubMed

Ding, Zhaofeng; Li, Jinrong; Spiegel, Daniel P; Chen, Zidong; Chan, Lily; Luo, Guangwei; Yuan, Junpeng; Deng, Daming; Yu, Minbin; Thompson, Benjamin

2016-01-14

Amblyopia is a neurodevelopmental disorder of vision that occurs when the visual cortex receives decorrelated inputs from the two eyes during an early critical period of development. Amblyopic eyes are subject to suppression from the fellow eye, generate weaker visual evoked potentials (VEPs) than fellow eyes and have multiple visual deficits including impairments in visual acuity and contrast sensitivity. Primate models and human psychophysics indicate that stronger suppression is associated with greater deficits in amblyopic eye contrast sensitivity and visual acuity. We tested whether transcranial direct current stimulation (tDCS) of the visual cortex would modulate VEP amplitude and contrast sensitivity in adults with amblyopia. tDCS can transiently alter cortical excitability and may influence suppressive neural interactions. Twenty-one patients with amblyopia and twenty-seven controls completed separate sessions of anodal (a-), cathodal (c-) and sham (s-) visual cortex tDCS. A-tDCS transiently and significantly increased VEP amplitudes for amblyopic, fellow and control eyes and contrast sensitivity for amblyopic and control eyes. C-tDCS decreased VEP amplitude and contrast sensitivity and s-tDCS had no effect. These results suggest that tDCS can modulate visual cortex responses to information from adult amblyopic eyes and provide a foundation for future clinical studies of tDCS in adults with amblyopia.

Stereo chromatic contrast sensitivity model to blue-yellow gratings.

PubMed

Yang, Jiachen; Lin, Yancong; Liu, Yun

2016-03-07

As a fundamental metric of human visual system (HVS), contrast sensitivity function (CSF) is typically measured by sinusoidal gratings at the detection of thresholds for psychophysically defined cardinal channels: luminance, red-green, and blue-yellow. Chromatic CSF, which is a quick and valid index to measure human visual performance and various retinal diseases in two-dimensional (2D) space, can not be directly applied into the measurement of human stereo visual performance. And no existing perception model considers the influence of chromatic CSF of inclined planes on depth perception in three-dimensional (3D) space. The main aim of this research is to extend traditional chromatic contrast sensitivity characteristics to 3D space and build a model applicable in 3D space, for example, strengthening stereo quality of 3D images. This research also attempts to build a vision model or method to check human visual characteristics of stereo blindness. In this paper, CRT screen was clockwise and anti-clockwise rotated respectively to form the inclined planes. Four inclined planes were selected to investigate human chromatic vision in 3D space and contrast threshold of each inclined plane was measured with 18 observers. Stimuli were isoluminant blue-yellow sinusoidal gratings. Horizontal spatial frequencies ranged from 0.05 to 5 c/d. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. According to the relationship between spatial frequency of inclined plane and horizontal spatial frequency, the chromatic contrast sensitivity characteristics in 3D space have been modeled based on the experimental data. The results show that the proposed model can well predicted human chromatic contrast sensitivity characteristics in 3D space.

The use of intrathecal analgesia and contrast radiography as preoperative diagnostic methods for digital flexor tendon sheath pathology.

PubMed

Fiske-Jackson, A R; Barker, W H J; Eliashar, E; Foy, K; Smith, R K W

2013-01-01

The sensitivity of ultrasonography for the diagnosis of manica flexoria (MF) tears within the digital flexor tendon sheath (DFTS) is lower than for diagnosis of marginal tears of the deep digital flexor tendon (DDFT). Additional diagnostic tools would assist in appropriate decision making for either conservative or surgical management. To evaluate the improvement in lameness of horses with MF or DDFT tears following intrathecal analgesia and to assess the sensitivity and specificity of contrast radiography for the diagnosis of these tears. The case records of horses presented to a referral clinic over a 7-year period that underwent intrathecal diagnostic analgesia, or intrathecal analgesia and contrast radiography, of the DFTS with subsequent tenoscopy were examined. Fifty-three limbs had intrathecal diagnostic analgesia performed and 23 contrast tenograms were assessed in horses undergoing DFTS tenoscopy. Horses with DDFT tears were significantly more likely to respond positively to intrathecal diagnostic analgesia than those with MF tears (P = 0.02). Using contrast radiography, tears of the MF were predicted with an overall sensitivity of 96% and specificity of 80%; marginal tears of the DDFT were predicted with an overall sensitivity of 57% and specificity of 84%. The results of intrathecal analgesia of the DFTS in combination with contrast radiography have a high sensitivity for predicting MF tears. The sensitivity of contrast radiography for predicting tears of the DDFT is lower but the specificity remains high. Contrast radiography performed at the same time as intrathecal analgesia provides useful information regarding the presence of MF tears and DDFT tears, which can assist in the decision of whether to manage the lameness conservatively or with tenoscopic evaluation. © 2012 EVJ Ltd.

A simple infrared-augmented digital photography technique for detection of pupillary abnormalities.

PubMed

Shazly, Tarek A; Bonhomme, G R

2015-03-01

The purpose of the study was to describe a simple infrared photography technique to aid in the diagnosis and documentation of pupillary abnormalities. An unmodified 12-megapixel "point and shoot" digital camera was used to obtain binocular still photos and videos under different light conditions with near-infrared illuminating frames. The near-infrared light of 850 nm allows the capture of clear pupil images in both dim and bright light conditions. It also allows easy visualization of the pupil despite pigmented irides by augmenting the contrast between the iris and the pupil. The photos and videos obtained illustrated a variety of pupillary abnormalities using the aforementioned technique. This infrared-augmented photography technique supplements medical education, and aids in the more rapid detection, diagnosis, and documentation of a wide spectrum of pupillary abnormalities. Its portability and ease of use with minimal training complements the education of trainees and facilitates the establishment of difficult diagnoses.

Clinical and Financial Impact of Ordering an Echocardiogram in Children with Left Axis Deviation on Their Electrocardiogram.

PubMed

Ravi, Prasad; Ashwath, Ravi; Strainic, James; Li, Hong; Steinberg, Jon; Snyder, Christopher

2016-01-01

Left axis deviation (LAD) on the electrocardiogram (ECG) is associated with congenital heart disease (CHD), prompting the clinician to order further testing when evaluating a patient with this finding. The purpose is to (1) compare the physical examination (PE) by a pediatric cardiologist to echocardiogram (ECHO) findings in patients with LAD on resting ECG and (2) assess cost of performing ECHO on all patients with LAD on ECG. An IRB approved, retrospective cohort study was performed on patients with LAD (QRS axis ≥0° to -90°) on ECG between 01/02 and 12/12. age >0.25 and <18 years, non-postoperative, and PE and ECHO by pediatric cardiologist. A decision tree model analyzed cost of ECHO in patients with LAD and normal/abnormal PE. Cost of complete ECHO ($239.00) was obtained from 2014 Medicare reimbursement rates. A total of 146 patients met inclusion criteria with 46.5% (68) having normal PE and ECHO, 1.4% (2) having normal PE and abnormal ECHO, 47.3% (69) having abnormal PE and ECHO, and 4.8% (7) having an abnormal PE and normal ECHO. Sensitivity and specificity of PE for detecting abnormalities in this population was 97% and 90%. Positive and negative predictive value of PE was 91% and 97.5%. In patients with normal PE, the cost to identify an ECHO abnormality was $8365, and $263 for those with abnormal PE. In presence of LAD on ECG, the sensitivity, specificity, and positive and negative predictive values of PE by a pediatric cardiologist are excellent at identifying CHD. Performing an ECHO on patients with LAD on ECG is only cost effective in the presence of an abnormal PE. In the presence of normal PE, there is a possibility of missing incidental structural cardiac disease in approximately 2% if an ECHO is not performed. © 2015 Wiley Periodicals, Inc.

Swimming attenuates d-galactose-induced brain aging via suppressing miR-34a-mediated autophagy impairment and abnormal mitochondrial dynamics.

PubMed

Kou, Xianjuan; Li, Jie; Liu, Xingran; Chang, Jingru; Zhao, Qingxia; Jia, Shaohui; Fan, Jingjing; Chen, Ning

2017-06-01

microRNAs (miRNAs) have been reported to be involved in many neurodegenerative diseases. To explore the regulatory role of miR-34a in aging-related diseases such as Alzheimer's disease (AD) during exercise intervention, we constructed a rat model with d-galactose (d-gal)-induced oxidative stress and cognitive impairment coupled with dysfunctional autophagy and abnormal mitochondrial dynamics, determined the mitigation of cognitive impairment of d-gal-induced aging rats during swimming intervention, and evaluated miR-34a-mediated functional status of autophagy and abnormal mitochondrial dynamics. Meanwhile, whether the upregulation of miR-34a can lead to dysfunctional autophagy and abnormal mitochondrial dynamics was confirmed in human SH-SY5Y cells with silenced miR-34a by the transfection of a miR-34a inhibitor. Results indicated that swimming intervention could significantly attenuate cognitive impairment, prevent the upregulation of miR-34a, mitigate the dysfunctional autophagy, and inhibit the increase of dynamin-related protein 1 (DRP1) in d-gal-induced aging model rats. In contrast, the miR-34a inhibitor in cell model not only attenuated D-gal-induced the impairment of autophagy but also decreased the expression of DRP1 and mitofusin 2 (MFN2). Therefore, swimming training can delay brain aging of d-gal-induced aging rats through attenuating the impairment of miR-34a-mediated autophagy and abnormal mitochondrial dynamics, and miR-34a could be the novel therapeutic target for aging-related diseases such as AD. NEW & NOTEWORTHY In the present study, we have found that the upregulation of miR-34a is the hallmark of aging or aging-related diseases, which can result in dysfunctional autophagy and abnormal mitochondrial dynamics. In contrast, swimming intervention can delay the aging process by rescuing the impaired functional status of autophagy and abnormal mitochondrial dynamics via the suppression of miR-34a. Copyright © 2017 the American Physiological Society.

Chromatic and achromatic monocular deprivation produce separable changes of eye dominance in adults.

PubMed

Zhou, Jiawei; Reynaud, Alexandre; Kim, Yeon Jin; Mullen, Kathy T; Hess, Robert F

2017-11-29

Temporarily depriving one eye of its input, in whole or in part, results in a transient shift in eye dominance in human adults, with the patched eye becoming stronger and the unpatched eye weaker. However, little is known about the role of colour contrast in these behavioural changes. Here, we first show that the changes in eye dominance and contrast sensitivity induced by monocular eye patching affect colour and achromatic contrast sensitivity equally. We next use dichoptic movies, customized and filtered to stimulate the two eyes differentially. We show that a strong imbalance in achromatic contrast between the eyes, with no colour content, also produces similar, unselective shifts in eye dominance for both colour and achromatic contrast sensitivity. Interestingly, if this achromatic imbalance is paired with similar colour contrast in both eyes, the shift in eye dominance is selective, affecting achromatic but not chromatic contrast sensitivity and revealing a dissociation in eye dominance for colour and achromatic image content. On the other hand, a strong imbalance in chromatic contrast between the eyes, with no achromatic content, produces small, unselective changes in eye dominance, but if paired with similar achromatic contrast in both eyes, no changes occur. We conclude that perceptual changes in eye dominance are strongly driven by interocular imbalances in achromatic contrast, with colour contrast having a significant counter balancing effect. In the short term, eyes can have different dominances for achromatic and chromatic contrast, suggesting separate pathways at the site of these neuroplastic changes. © 2017 The Author(s).

A gaze-contingent display to study contrast sensitivity under natural viewing conditions

NASA Astrophysics Data System (ADS)

Dorr, Michael; Bex, Peter J.

2011-03-01

Contrast sensitivity has been extensively studied over the last decades and there are well-established models of early vision that were derived by presenting the visual system with synthetic stimuli such as sine-wave gratings near threshold contrasts. Natural scenes, however, contain a much wider distribution of orientations, spatial frequencies, and both luminance and contrast values. Furthermore, humans typically move their eyes two to three times per second under natural viewing conditions, but most laboratory experiments require subjects to maintain central fixation. We here describe a gaze-contingent display capable of performing real-time contrast modulations of video in retinal coordinates, thus allowing us to study contrast sensitivity when dynamically viewing dynamic scenes. Our system is based on a Laplacian pyramid for each frame that efficiently represents individual frequency bands. Each output pixel is then computed as a locally weighted sum of pyramid levels to introduce local contrast changes as a function of gaze. Our GPU implementation achieves real-time performance with more than 100 fps on high-resolution video (1920 by 1080 pixels) and a synthesis latency of only 1.5ms. Psychophysical data show that contrast sensitivity is greatly decreased in natural videos and under dynamic viewing conditions. Synthetic stimuli therefore only poorly characterize natural vision.

Long lasting effects of daily theta burst rTMS sessions in the human amblyopic cortex.

PubMed

Clavagnier, Simon; Thompson, Benjamin; Hess, Robert F

2013-11-01

It has been reported that a single session of 1 Hz or 10 Hz repetitive transcranial magnetic stimulation (rTMS) of the visual cortex can temporarily improve contrast sensitivity in adults with amblyopia. More recently, continuous theta burst stimulation (cTBS) of the visual cortex has been found to improve contrast sensitivity in observers with normal vision. The aims of this study were to assess whether cTBS of the visual cortex could improve contrast sensitivity in adults with amblyopia and whether repeated sessions of cTBS would lead to more pronounced and/or longer lasting effects. cTBS was delivered to the visual cortex while patients viewed a high contrast stimulus with their non-amblyopic eye. This manipulation was designed to bias the effects of cTBS toward inputs from the amblyopic eye. Contrast sensitivity was measured before and after stimulation. The effects of one cTBS session were measured in five patients and the effects of five consecutive daily sessions were measured in four patients. Three patients were available for follow-up at varying intervals after the final session. cTBS improved amblyopic eye contrast sensitivity to high spatial frequencies (P < 0.05) and there was a cumulative improvement across sessions with asymptotic improvement occurring after 2 daily sessions of stimulation. The contrast sensitivity improvements were stable over a period of up to 78 days. These initial results in a small number of patients indicate the cTBS may allow for enduring visual function improvements in adults with amblyopia. Copyright © 2013 Elsevier Inc. All rights reserved.

Functional changes after treatment of optic pathway paediatric low-grade gliomas

PubMed Central

Magli, A; Forte, R; Cinalli, G; Esposito, F; Parisi, S; Capasso, M; Papparella, A

2013-01-01

Objective To evaluate the functional changes after treatment of paediatric optic pathway gliomas (OPGs). Methods All patients with monofocal OPG seen from January 2004 to January 2011 were included. Best corrected visual acuity (BCVA, LogMAR), contrast sensitivity (Hiding-Heidi low-contrast ‘face' test (HH) and Pelli−Robson (PR) contrast sensitivity test), and the Color Test (Ishihara plate) were obtained. Results Twenty-one patients (10 boys and 11 girls with a mean age of 5.5±4.4 years at diagnosis) were included in the study. Neurofibromatosis was present in four cases. Eighteen patients (85.7%) were treated with initial surgery and three patients (14.3%) with initial chemotherapy. BCVA was 0.67±0.8 LogMAR at baseline and 0.62±0.9 LogMAR at last visit (P=0.41). The Color test was not significantly changed at last visit (P=0.62). Contrast sensitivity with the HH test was 9.1±11.1% at baseline and 3.8±6.4% at last visit (P=0.03). Contrast sensitivity with PR chart was 1.33±0.9log at baseline and 1.05±0.7 log at last visit (P=0.005). A reduction in contrast sensitivity at both tests was significantly greater in patients who relapsed than in patients who did not relapse (P=0.001). Conclusion After the treatment of paediatric optic pathway low-grade gliomas, a reduction in contrast sensitivity during follow-up was observed and may be correlated with tumour relapses. PMID:23970029

Intratumoral genetic heterogeneity in metastatic melanoma is accompanied by variation in malignant behaviors.

PubMed

Anaka, Matthew; Hudson, Christopher; Lo, Pu-Han; Do, Hongdo; Caballero, Otavia L; Davis, Ian D; Dobrovic, Alexander; Cebon, Jonathan; Behren, Andreas

2013-10-11

Intratumoral heterogeneity is a major obstacle for the treatment of cancer, as the presence of even minor populations that are insensitive to therapy can lead to disease relapse. Increased clonal diversity has been correlated with a poor prognosis for cancer patients, and we therefore examined genetic, transcriptional, and functional diversity in metastatic melanoma. Amplicon sequencing and SNP microarrays were used to profile somatic mutations and DNA copy number changes in multiple regions from metastatic lesions. Clonal genetic and transcriptional heterogeneity was also assessed in single cell clones from early passage cell lines, which were then subjected to clonogenicity and drug sensitivity assays. MAPK pathway and tumor suppressor mutations were identified in all regions of the melanoma metastases analyzed. In contrast, we identified copy number abnormalities present in only some regions in addition to homogeneously present changes, suggesting ongoing genetic evolution following metastatic spread. Copy number heterogeneity from a tumor was represented in matched cell line clones, which also varied in their clonogenicity and drug sensitivity. Minor clones were identified based on dissimilarity to the parental cell line, and these clones were the most clonogenic and least sensitive to drugs. Finally, treatment of a polyclonal cell line with paclitaxel to enrich for drug-resistant cells resulted in the adoption of a gene expression profile with features of one of the minor clones, supporting the idea that these populations can mediate disease relapse. Our results support the hypothesis that minor clones might have major consequences for patient outcomes in melanoma.

Scatterer density sensitive tomography utilizing light and ultrasound

NASA Astrophysics Data System (ADS)

Vakili, Ali; Holt, R. Glynn; DiMarzio, Charles A.

2018-02-01

Hybrid imaging modalities are becoming more popular since they utilize the benefit of both optical and ultrasound (US) imaging modalities. They use the contrast based on optical properties and negligible scattering of US waves to extend the depth of imaging. Ultrasound modulated optical tomography (UOT) and acoustic radiation force (ARF) with speckle pattern analysis, both use the idea of utilizing a focused US wave to spatially encode in information in the diffused light. We have previously shown that compared to UOT, ARF regime can result in a stronger signal and the mean irradiance change (MIC) signal can reflect the mechanical and thermal properties of the tissue non-invasively. In addition to the mechanical and thermal properties of the medium, the MIC signal is able to reveal information about the morphology of the medium. A tumor is formed by a group of cancer cells that are result of rounds of successive mutation. Cancer cell grow without control in abnormal shapes. In this study, we have modeled cells with their nuclei, assuming that the scattering events occur at the location of the nuclei of the cells. We have shown that, although the MIC signal is not sensitive to the size of the particle, it can detect the presence of the tumor base on the higher concentration of cells in a tumor.

Visual function of police officers who have undergone refractive surgery.

PubMed

Hovis, Jeffery K; Ramaswamy, Shankaran

2006-11-01

The visual acuity and contrast sensitivity of police recruits and officers was evaluated in both normal and dim illumination conditions to determine whether officers who have had refractive surgery have compromised night vision. The control group consisted of 76 officers and recruits who have not had refractive surgery and the refractive surgery group consisted of 22 officers and recruits who had refractive surgery. Visual acuity and contrast sensitivity were measured under both room illumination and dim illumination. The room illumination test series included high contrast acuity, low contrast acuity and Pelli-Robson contrast sensitivity. The dim illumination test series included high contrast acuity, low contrast acuity, Pelli-Robson contrast sensitivity, license plate number acuity (with and without glare) and the Mesotest. The general findings were that the refractive surgery group had lower acuity scores on low contrast targets in both room and dim light levels along with a reduction in the Mesotest scores with a glare source compared to the control group. Although refractive surgery police recruits and officers had reduced performance on some vision tests, these reductions were small and it is unlikely that their performance on vision related tasks would be compromised, on average. The major concern is the small number of refractive surgery candidates whose results were well outside the range of the non-surgical candidates. Their vision may be unacceptable for policing. Copyright (c) 2006 Wiley-Liss, Inc.

Do common mechanisms of adaptation mediate color discrimination and appearance? Contrast adaptation

NASA Astrophysics Data System (ADS)

Hillis, James M.; Brainard, David H.

2007-08-01

Are effects of background contrast on color appearance and sensitivity controlled by the same mechanism of adaptation? We examined the effects of background color contrast on color appearance and on color-difference sensitivity under well-matched conditions. We linked the data using Fechner's hypothesis that the rate of apparent stimulus change is proportional to sensitivity and examined a family of parametric models of adaptation. Our results show that both appearance and discrimination are consistent with the same mechanism of adaptation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, I.C.; Ko, S.F.; Shieh, C.S.

Ehlers-Danlos syndrome (EDS) includes a group of connective tissue disorders with abnormal collagen metabolism and a diverse clinical spectrum. We report two siblings with EDS who both presented with congenital diaphragmatic hernia (CDH). The elder sister suffered from recurrent diaphragmatic hernia twice and EDS was overlooked initially. Echocardiography as well as contrast-enhanced magnetic resonance angiography (MRA) showed dilatation of the pulmonary artery, and marked elongation and tortuosity of the aorta and its branches. A diagnosis of EDS was eventually established when these findings were coupled with the clinical features of hyperelastic skin. Her younger brother also had similar features. Thismore » report emphasizes that EDS may present as CDH in a small child which could easily be overlooked. Without appropriate surgery, diaphragmatic hernia might occur. Echocardiographic screening is recommended in patients with CDH. Contrast-enhanced MRA can be helpful in delineation of abnormally tortuous aortic great vessels that are an important clue to the early diagnosis of EDS.« less

Sensitivity, specificity, and predictive values of pediatric metabolic syndrome components in relation to adult metabolic syndrome: the Princeton LRC follow-up study.

PubMed

Huang, Terry T-K; Nansel, Tonja R; Belsheim, Allen R; Morrison, John A

2008-02-01

To estimate the sensitivity, specificity, and predictive values of pediatric metabolic syndrome (MetS) components (obesity, fasting glucose, triglycerides, high-density lipoprotein, and blood pressure) at various cutoff points in relation to adult MetS. Data from the National Heart, Lung, and Blood Institute Lipid Research Clinics Princeton Prevalence Study (1973-1976) and the Princeton Follow-up Study (2000-2004) were used to calculate sensitivity, specificity, and positive and negative predictive values for each component at a given cutoff point and for aggregates of components. Individual pediatric components alone showed low to moderate sensitivity, high specificity, and moderate predictive values in relation to adult MetS. When all 5 pediatric MetS components were considered, the presence of at least 1 abnormality had higher sensitivity for adult MetS than individual components alone. When multiple abnormalities were mandatory for MetS, positive predictive value was high and sensitivity was low. Childhood body mass alone showed neither high sensitivity nor high positive predictive value for adult MetS. Considering multiple metabolic variables in childhood can improve the predictive usefulness for adult MetS, compared with each component or body mass alone. MetS variables may be useful for identifying some children who are at risk for prevention interventions.

Prediction of vascular abnormalities on CT angiography in patients with acute headache.

PubMed

Alons, Imanda M E; Goudsmit, Ben F J; Jellema, Korné; van Walderveen, Marianne A A; Wermer, Marieke J H; Algra, Ale

2018-05-09

Patients with acute headache increasingly undergo CT-angiography (CTA) to evaluate underlying vascular causes. The aim of this study is to determine clinical and non-contrast CT (NCCT) criteria to select patients who might benefit from CTA. We retrospectively included patients with acute headache who presented to the emergency department of an academic medical center and large regional teaching hospital and underwent NCCT and CTA. We identified factors that increased the probability of finding a vascular abnormality on CTA, performed multivariable regression analyses and determined discrimination with the c-statistic. A total of 384 patients underwent NCCT and CTA due to acute headache. NCCT was abnormal in 194 patients. Among these, we found abnormalities in 116 cases of which 99 aneurysms. In the remaining 190 with normal NCCT we found abnormalities in 12 cases; four unruptured aneurysms, three cerebral venous thrombosis', two reversible cerebral vasoconstriction syndromes, two cervical arterial dissections and one cerebellar infarction. In multivariable analysis abnormal NCCT, lowered consciousness and presentation within 6 hr of headache onset were independently associated with abnormal CTA. The c-statistic of abnormal NCCT alone was 0.80 (95% CI: 0.75-0.80), that also including the other two variables was 0.84 (95% CI: 0.80-0.88). If NCCT was normal no other factors could help identify patients at risk for abnormalities. In patients with acute headache abnormal NCCT is the strongest predictor of a vascular abnormality on CTA. If NCCT is normal no other predictors increase the probability of finding an abnormality on CTA and diagnostic yield is low. © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.

Electron microscopic diagnosis of human flavivirus encephalitis: use of confocal microscopy as an aid.

PubMed

Chu, C T; Howell, D N; Morgenlander, J C; Hulette, C M; McLendon, R E; Miller, S E

1999-10-01

The distinction between intracranial viral infections and inflammatory conditions requiring immunosuppression is important. Although specific laboratory reagents are readily available for some viruses, diagnosis of arbovirus infection is more difficult. Transmission electron microscopy (TEM) theoretically allows identification of viral particles independent of reagent availability, but it has limited sensitivity. We report two cases of human flavivirus encephalitis diagnosed by TEM. Laser scanning confocal microscopy (LSCM) was used in one case to survey unembedded tissue slices for focal abnormalities, from which fragments smaller than 1 mm2 were excised for epoxy embedding. This facilitated TEM identification of intracytoplasmic, budding, 35-40 nm spherical virus particles, confirmed by serology as St. Louis encephalitis. In contrast to mosquitoes and newborn mice, in which high viral loads are associated with minimal tissue responses, these biopsies showed florid angiodestructive inflammation and microgliosis, with rare virions in necrotic perivascular cells and astrocytes. To our knowledge, this represents the first ultrastructural study of St. Louis encephalitis in humans, indicating the potential value of LSCM-aided TEM.

The accuracy of ultrasound in the diagnosis of congenital abnormalities.

PubMed

Munim, Shama; Nadeem, Salva; Khuwaja, Nadya Ali

2006-01-01

To determine the accuracy of ultrasound in the diagnosis of congenital abnormalities at the Aga Khan University Hospital, Karachi. The data of congenital abnormalities was obtained from the obstetrical database and medical records of all cases complicated by congenital abnormalities, delivering from January 2001 to December 2003 and was reviewed. Antenatal ultrasounds had been performed by operators with different level of experience. In addition this data was retrieved from the termination and Congenital anomaly register. A structured data collection form was used to collect information of different variables of interest. Congenital abnormalities, complicated 2.8% (n=170), of all deliveries, including all cases of termination of pregnancy, stillbirth and live births. Out of the total, 11.6% occurred in women above the age of 35 years. Consanguinity was found in 18.2% cases. Prenatal diagnosis was made in just under half of the cases (48.8%). Central nervous system and renal abnormalities were commonly diagnosed. However, facial defects, heart defects or skeletal defects were more commonly missed. Antenatal ultrasound successfully diagnosed foetal abnormalities in 48.8% of cases, and more than 90% Central Nervous system defects and renal abnormalities. In contrast about a quarter of Cardiac defects and none of the facial defects were detected. Based on these findings we recommend that the Sonologist should incorporate four chamber view of the heart and also look at the face carefully.

Seizure classification in EEG signals utilizing Hilbert-Huang transform

PubMed Central

2011-01-01

Background Classification method capable of recognizing abnormal activities of the brain functionality are either brain imaging or brain signal analysis. The abnormal activity of interest in this study is characterized by a disturbance caused by changes in neuronal electrochemical activity that results in abnormal synchronous discharges. The method aims at helping physicians discriminate between healthy and seizure electroencephalographic (EEG) signals. Method Discrimination in this work is achieved by analyzing EEG signals obtained from freely accessible databases. MATLAB has been used to implement and test the proposed classification algorithm. The analysis in question presents a classification of normal and ictal activities using a feature relied on Hilbert-Huang Transform. Through this method, information related to the intrinsic functions contained in the EEG signal has been extracted to track the local amplitude and the frequency of the signal. Based on this local information, weighted frequencies are calculated and a comparison between ictal and seizure-free determinant intrinsic functions is then performed. Methods of comparison used are the t-test and the Euclidean clustering. Results The t-test results in a P-value < 0.02 and the clustering leads to accurate (94%) and specific (96%) results. The proposed method is also contrasted against the Multivariate Empirical Mode Decomposition that reaches 80% accuracy. Comparison results strengthen the contribution of this paper not only from the accuracy point of view but also with respect to its fast response and ease to use. Conclusion An original tool for EEG signal processing giving physicians the possibility to diagnose brain functionality abnormalities is presented in this paper. The proposed system bears the potential of providing several credible benefits such as fast diagnosis, high accuracy, good sensitivity and specificity, time saving and user friendly. Furthermore, the classification of mode mixing can be achieved using the extracted instantaneous information of every IMF, but it would be most likely a hard task if only the average value is used. Extra benefits of this proposed system include low cost, and ease of interface. All of that indicate the usefulness of the tool and its use as an efficient diagnostic tool. PMID:21609459

Seizure classification in EEG signals utilizing Hilbert-Huang transform.

PubMed

Oweis, Rami J; Abdulhay, Enas W

2011-05-24

Classification method capable of recognizing abnormal activities of the brain functionality are either brain imaging or brain signal analysis. The abnormal activity of interest in this study is characterized by a disturbance caused by changes in neuronal electrochemical activity that results in abnormal synchronous discharges. The method aims at helping physicians discriminate between healthy and seizure electroencephalographic (EEG) signals. Discrimination in this work is achieved by analyzing EEG signals obtained from freely accessible databases. MATLAB has been used to implement and test the proposed classification algorithm. The analysis in question presents a classification of normal and ictal activities using a feature relied on Hilbert-Huang Transform. Through this method, information related to the intrinsic functions contained in the EEG signal has been extracted to track the local amplitude and the frequency of the signal. Based on this local information, weighted frequencies are calculated and a comparison between ictal and seizure-free determinant intrinsic functions is then performed. Methods of comparison used are the t-test and the Euclidean clustering. The t-test results in a P-value < 0.02 and the clustering leads to accurate (94%) and specific (96%) results. The proposed method is also contrasted against the Multivariate Empirical Mode Decomposition that reaches 80% accuracy. Comparison results strengthen the contribution of this paper not only from the accuracy point of view but also with respect to its fast response and ease to use. An original tool for EEG signal processing giving physicians the possibility to diagnose brain functionality abnormalities is presented in this paper. The proposed system bears the potential of providing several credible benefits such as fast diagnosis, high accuracy, good sensitivity and specificity, time saving and user friendly. Furthermore, the classification of mode mixing can be achieved using the extracted instantaneous information of every IMF, but it would be most likely a hard task if only the average value is used. Extra benefits of this proposed system include low cost, and ease of interface. All of that indicate the usefulness of the tool and its use as an efficient diagnostic tool.

Contrast-Enhanced Ultrasound as a New Investigative Tool in Diagnostic Imaging of Muscle Injuries-A Pilot Study Evaluating Conventional Ultrasound, CEUS, and Findings in MRI.

PubMed

Hotfiel, Thilo; Heiss, Rafael; Swoboda, Bernd; Kellermann, Marion; Gelse, Kolja; Grim, Casper; Strobel, Deike; Wildner, Dane

2018-07-01

To emphasize the diagnostic value of contrast-enhanced ultrasound (CEUS) in the imaging of muscle injuries with different degrees of severity by comparing findings to established imaging modalities such as conventional ultrasound and magnetic resonance imaging (MRI). Case series. Institutional study. Conventional ultrasound and CEUS were performed in the Department of Internal Medicine. Magnetic resonance imaging was carried out in the Department of Radiology within the Magnetom Avanto 1.5T and Magnetom Skyra fit 3T (Siemens Healthineers, Erlangen, Germany) and in the Institution of Imaging Diagnostics and Therapy (Magnetom Avanto 1.5T; Siemens, Erlangen, Germany). Fifteen patients who underwent an acute muscle injury were recruited. The appearance and detectable size of muscle injuries were compared between each imaging modality. The injuries were assessed by 3 independent observers and blinded between imaging modalities. All 15 injuries were identified on MRI and CEUS, whereas 10 injuries showed abnormalities in conventional ultrasound. The determination and measurement revealed significant differences between conventional ultrasound and CEUS depending on injury severity. Contrast-enhanced ultrasound revealed an impairment of microcirculation in grade I lesions (corresponding to intramuscular edema observed in MRI), which was not detectable using conventional ultrasound. Our results indicate that performing CEUS seems to be a sensitive additional diagnostic modality in the early assessment of muscle injuries. Our results highlight the advantages of CEUS in the imaging of low-grade lesions when compared with conventional ultrasound, as this was the more accurate modality for identifying intramuscular edema.

Cerebrospinal Fluid (CSF) Neuronal Biomarkers across the Spectrum of HIV Infection: Hierarchy of Injury and Detection

PubMed Central

Peterson, Julia; Gisslen, Magnus; Zetterberg, Henrik; Fuchs, Dietmar; Shacklett, Barbara L.; Hagberg, Lars; Yiannoutsos, Constantin T.; Spudich, Serena S.; Price, Richard W.

2014-01-01

The character of central nervous system (CNS) HIV infection and its effects on neuronal integrity vary with evolving systemic infection. Using a cross-sectional design and archived samples, we compared concentrations of cerebrospinal fluid (CSF) neuronal biomarkers in 143 samples from 8 HIV-infected subject groups representing a spectrum of untreated systemic HIV progression and viral suppression: primary infection; four groups of chronic HIV infection neuroasymptomatic (NA) subjects defined by blood CD4+ T cells of >350, 200–349, 50–199, and <50 cells/µL; HAD; treatment-induced viral suppression; and ‘elite’ controllers. Samples from 20 HIV-uninfected controls were also examined. The neuronal biomarkers included neurofilament light chain protein (NFL), total and phosphorylated tau (t-tau, p-tau), soluble amyloid precursor proteins alpha and beta (sAPPα, sAPPβ) and amyloid beta (Aβ) fragments 1–42, 1–40 and 1–38. Comparison of the biomarker changes showed a hierarchy of sensitivity in detection and suggested evolving mechanisms with progressive injury. NFL was the most sensitive neuronal biomarker. Its CSF concentration exceeded age-adjusted norms in all HAD patients, 75% of NA CD4<50, 40% of NA CD4 50–199, and 42% of primary infection, indicating common neuronal injury with untreated systemic HIV disease progression as well as transiently during early infection. By contrast, only 75% of HAD subjects had abnormal CSF t-tau levels, and there were no significant differences in t-tau levels among the remaining groups. sAPPα and β were also abnormal (decreased) in HAD, showed less marked change than NFL with CD4 decline in the absence of HAD, and were not decreased in PHI. The CSF Aβ peptides and p-tau concentrations did not differ among the groups, distinguishing the HIV CNS injury profile from Alzheimer's disease. These CSF biomarkers can serve as useful tools in selected research and clinical settings for patient classification, pathogenetic analysis, diagnosis and management. PMID:25541953

Differences in neural crest sensitivity to ethanol account for the infrequency of anterior segment defects in the eye compared with craniofacial anomalies in a zebrafish model of fetal alcohol syndrome.

PubMed

Eason, Jessica; Williams, Antionette L; Chawla, Bahaar; Apsey, Christian; Bohnsack, Brenda L

2017-09-01

Ethanol (ETOH) exposure during pregnancy is associated with craniofacial and neurologic abnormalities, but infrequently disrupts the anterior segment of the eye. In these studies, we used zebrafish to investigate differences in the teratogenic effect of ETOH on craniofacial, periocular, and ocular neural crest. Zebrafish eye and neural crest development was analyzed by means of live imaging, TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay, immunostaining, detection of reactive oxygen species, and in situ hybridization. Our studies demonstrated that foxd3-positive neural crest cells in the periocular mesenchyme and developing eye were less sensitive to ETOH than sox10-positive craniofacial neural crest cells that form the pharyngeal arches and jaw. ETOH increased apoptosis in the retina, but did not affect survival of periocular and ocular neural crest cells. ETOH also did not increase reactive oxygen species within the eye. In contrast, ETOH increased ventral neural crest apoptosis and reactive oxygen species production in the facial mesenchyme. In the eye and craniofacial region, sod2 showed high levels of expression in the anterior segment and in the setting of Sod2 knockdown, low levels of ETOH decreased migration of foxd3-positive neural crest cells into the developing eye. However, ETOH had minimal effect on the periocular and ocular expression of transcription factors (pitx2 and foxc1) that regulate anterior segment development. Neural crest cells contributing to the anterior segment of the eye exhibit increased ability to withstand ETOH-induced oxidative stress and apoptosis. These studies explain the rarity of anterior segment dysgenesis despite the frequent craniofacial abnormalities in fetal alcohol syndrome. Birth Defects Research 109:1212-1227, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Cerebrospinal fluid (CSF) neuronal biomarkers across the spectrum of HIV infection: hierarchy of injury and detection.

PubMed

Peterson, Julia; Gisslen, Magnus; Zetterberg, Henrik; Fuchs, Dietmar; Shacklett, Barbara L; Hagberg, Lars; Yiannoutsos, Constantin T; Spudich, Serena S; Price, Richard W

2014-01-01

The character of central nervous system (CNS) HIV infection and its effects on neuronal integrity vary with evolving systemic infection. Using a cross-sectional design and archived samples, we compared concentrations of cerebrospinal fluid (CSF) neuronal biomarkers in 143 samples from 8 HIV-infected subject groups representing a spectrum of untreated systemic HIV progression and viral suppression: primary infection; four groups of chronic HIV infection neuroasymptomatic (NA) subjects defined by blood CD4+ T cells of >350, 200-349, 50-199, and <50 cells/µL; HAD; treatment-induced viral suppression; and 'elite' controllers. Samples from 20 HIV-uninfected controls were also examined. The neuronal biomarkers included neurofilament light chain protein (NFL), total and phosphorylated tau (t-tau, p-tau), soluble amyloid precursor proteins alpha and beta (sAPPα, sAPPβ) and amyloid beta (Aβ) fragments 1-42, 1-40 and 1-38. Comparison of the biomarker changes showed a hierarchy of sensitivity in detection and suggested evolving mechanisms with progressive injury. NFL was the most sensitive neuronal biomarker. Its CSF concentration exceeded age-adjusted norms in all HAD patients, 75% of NA CD4<50, 40% of NA CD4 50-199, and 42% of primary infection, indicating common neuronal injury with untreated systemic HIV disease progression as well as transiently during early infection. By contrast, only 75% of HAD subjects had abnormal CSF t-tau levels, and there were no significant differences in t-tau levels among the remaining groups. sAPPα and β were also abnormal (decreased) in HAD, showed less marked change than NFL with CD4 decline in the absence of HAD, and were not decreased in PHI. The CSF Aβ peptides and p-tau concentrations did not differ among the groups, distinguishing the HIV CNS injury profile from Alzheimer's disease. These CSF biomarkers can serve as useful tools in selected research and clinical settings for patient classification, pathogenetic analysis, diagnosis and management.

The development and initial validation of a sensitive bedside cognitive screening test.

PubMed

Faust, D; Fogel, B S

1989-01-01

Brief bedside cognitive examinations such as the Mini-Mental State Examination are designed to detect delirium and dementia but not more subtle or delineated cognitive deficits. Formal neuropsychological evaluation provides greater sensitivity and detects a wider range of cognitive deficits but is too lengthy for efficient use at the bedside or in epidemiological studies. The authors developed the High Sensitivity Cognitive Screen (HSCS), a 20-minute interview-based test, to identify patients who show disorder on formal neuropsychological evaluation. An initial study demonstrated satisfactory test-retest and interrater reliability. The HSCS was then administered to 60 psychiatric and neurological patients with suspected cognitive deficits but without gross impairment, who also completed formal neuropsychological testing. Results of both tests were independently classified as either normal, borderline, or abnormal. The HSCS correctly classified 93% of patients across the normal-abnormal dichotomy and showed promise for characterizing the extent and severity of cognitive dysfunction.

Direct Regularization From Co-Registered Contrast MRI Improves Image Quality of MRI-Guided Near-Infrared Spectral Tomography of Breast Lesions.

PubMed

Zhang, Limin; Jiang, Shudong; Zhao, Yan; Feng, Jinchao; Pogue, Brian W; Paulsen, Keith D

2018-05-01

An approach using direct regularization from co-registered dynamic contrast enhanced magnetic reson- ance images was used to reconstruct near-infrared spectral tomography patient images, which does not need image segmentation. 20 patients with mammography/ultrasound confirmed breast abnormalities were involved in this paper, and the resulting images indicated that tumor total hemoglobin concentration contrast differentiated malignant from benign cases (p-value = 0.021). The approach prod- uced reconstructed images, which significantly reduced surface artifacts near the source-detector locations (p-value = 4.16e-6).

Abnormal Canine Bone Development Associated with Hypergravity Exposure

NASA Technical Reports Server (NTRS)

Morgan, J. P.; Fisher, G. L.; McNeill, K. L.; Oyama, J.

1979-01-01

Chronic centrifugation of 85- to 92-day-old Beagles at 2.0 x g and 2.6 x g for 26 weeks during the time of active skeletal growth caused skeletal abnormalities in the radius and the ulna of ten of 11 dogs. The pattern of change mimicked that found in naturally occurring and experimentally induced premature distal ulnar physeal closure or delayed growth at this physis. Minimal changes in bone density were detected by sensitive photon absorptiometric techniques. Skeletal abnormalities also were found in five of the six cage-control dogs, although the run-control dogs were radiographically normal.

Ultrasound as a screening test for genitourinary anomalies in children with UTI.

PubMed

Nelson, Caleb P; Johnson, Emilie K; Logvinenko, Tanya; Chow, Jeanne S

2014-03-01

The 2011 American Academy of Pediatrics guidelines state that renal and bladder ultrasound (RBUS) should be performed after initial febrile urinary tract infection (UTI) in a young child, with voiding cystourethrogram (VCUG) performed only if RBUS shows abnormalities. We sought to determine test characteristics and predictive values of RBUS for VCUG findings in this setting. We analyzed 3995 clinical encounters from January 1, 2006 to December 31, 2010 during which VCUG and RBUS were performed for history of UTI. Patients who had previous postnatal genitourinary imaging or history of prenatal hydronephrosis were excluded. Sensitivity, specificity, and predictive values of RBUS for VCUG abnormalities were determined. We identified 2259 patients age <60 months who had UTI as the indication for imaging. RBUS was reported as "normal" in 75%. On VCUG, any vesicoureteral reflux (VUR) was identified in 41.7%, VUR grade >II in 20.9%, and VUR grade >III in 2.8%. Sensitivity of RBUS for any abnormal findings on VCUG ranged from 5% (specificity: 97%) to 28% (specificity: 77%). Sensitivity for VUR grade >III ranged from 18% (specificity: 97%) to 55% (specificity: 77%). Among the 1203 children aged 2 to 24 months imaged after a first febrile UTI, positive predictive value of RBUS was 37% to 47% for VUR grade >II (13% to 24% for VUR grade >III); negative predictive value was 72% to 74% for VUR grade >II (95% to 96% for VUR grade >III). RBUS is a poor screening test for genitourinary abnormalities. RBUS and VCUG should be considered complementary as they provide important, but different, information.

Ultrasound as a Screening Test for Genitourinary Anomalies in Children With UTI

PubMed Central

Johnson, Emilie K.; Logvinenko, Tanya; Chow, Jeanne S.

2014-01-01

BACKGROUND: The 2011 American Academy of Pediatrics guidelines state that renal and bladder ultrasound (RBUS) should be performed after initial febrile urinary tract infection (UTI) in a young child, with voiding cystourethrogram (VCUG) performed only if RBUS shows abnormalities. We sought to determine test characteristics and predictive values of RBUS for VCUG findings in this setting. METHODS: We analyzed 3995 clinical encounters from January 1, 2006 to December 31, 2010 during which VCUG and RBUS were performed for history of UTI. Patients who had previous postnatal genitourinary imaging or history of prenatal hydronephrosis were excluded. Sensitivity, specificity, and predictive values of RBUS for VCUG abnormalities were determined. RESULTS: We identified 2259 patients age <60 months who had UTI as the indication for imaging. RBUS was reported as “normal” in 75%. On VCUG, any vesicoureteral reflux (VUR) was identified in 41.7%, VUR grade >II in 20.9%, and VUR grade >III in 2.8%. Sensitivity of RBUS for any abnormal findings on VCUG ranged from 5% (specificity: 97%) to 28% (specificity: 77%). Sensitivity for VUR grade >III ranged from 18% (specificity: 97%) to 55% (specificity: 77%). Among the 1203 children aged 2 to 24 months imaged after a first febrile UTI, positive predictive value of RBUS was 37% to 47% for VUR grade >II (13% to 24% for VUR grade >III); negative predictive value was 72% to 74% for VUR grade >II (95% to 96% for VUR grade >III). CONCLUSIONS: RBUS is a poor screening test for genitourinary abnormalities. RBUS and VCUG should be considered complementary as they provide important, but different, information. PMID:24515519

Migraine: Multiple Processes, Complex Pathophysiology

PubMed Central

Noseda, Rodrigo; Borsook, David

2015-01-01

Migraine is a common, multifactorial, disabling, recurrent, hereditary neurovascular headache disorder. It usually strikes sufferers a few times per year in childhood and then progresses to a few times per week in adulthood, particularly in females. Attacks often begin with warning signs (prodromes) and aura (transient focal neurological symptoms) whose origin is thought to involve the hypothalamus, brainstem, and cortex. Once the headache develops, it typically throbs, intensifies with an increase in intracranial pressure, and presents itself in association with nausea, vomiting, and abnormal sensitivity to light, noise, and smell. It can also be accompanied by abnormal skin sensitivity (allodynia) and muscle tenderness. Collectively, the symptoms that accompany migraine from the prodromal stage through the headache phase suggest that multiple neuronal systems function abnormally. As a consequence of the disease itself or its genetic underpinnings, the migraine brain is altered structurally and functionally. These molecular, anatomical, and functional abnormalities provide a neuronal substrate for an extreme sensitivity to fluctuations in homeostasis, a decreased ability to adapt, and the recurrence of headache. Advances in understanding the genetic predisposition to migraine, and the discovery of multiple susceptible gene variants (many of which encode proteins that participate in the regulation of glutamate neurotransmission and proper formation of synaptic plasticity) define the most compelling hypothesis for the generalized neuronal hyperexcitability and the anatomical alterations seen in the migraine brain. Regarding the headache pain itself, attempts to understand its unique qualities point to activation of the trigeminovascular pathway as a prerequisite for explaining why the pain is restricted to the head, often affecting the periorbital area and the eye, and intensifies when intracranial pressure increases. PMID:25926442

Quantity and Quality of Vision Using Tinted Filters in Patients with Low Vision Due to Diabetic Retinopathy.

PubMed

Sadeghpour, Naser; Alishiri, Ali Agha; Ajudani, Reza; Khosravi, Mohammad Hossein; Amiri, Mohammad Aghazadeh; Sadeghpour, Omid

2015-01-01

To investigate the effect of tinted filters on visual acuity (VA), contrast sensitivity and patient satisfaction in diabetic retinopathy associated with low vision. In a prospective study, 51 patients with diabetic retinopathy and low vision were assessed. We chose a simple random sampling method and used the patient's files for data collection. LogMAR notations were applied for assessing VA and a contrast sensitivity chart (CSV-1000) was employed for measuring contrast sensitivity. First, measurements were performed without tinted filters and then using them. Appropriate lenses were given to the patients for 2 days, and they were questioned about their satisfaction using them in different places. A total of 20 male and 31 female patients with mean age of 57.3 years participated in the study. With a 527 ± 10 nm filter, mean VA improved significantly (P ≤ 0.05). Using the 527 ± 10 nm and 511 ± 10 nm filters, mean contrast sensitivity was improved significantly at 3 and 6 cycles/degree frequencies (P < 0.05). The effect of other filters on VA and contrast sensitivity was not significant. Patient satisfaction rate was generally high. Tinted filters are able to rehabilitate low-vision patients due to diabetic retinopathy. The 527 ± 10 and 511 ± 10 nm wavelength filters improved contrast sensitivity and the 527 ± 10 nm filter improved VA to some extent. Further investigations are recommended to assess the effect of these filters in patients with other causes of low-vision.

Spherical aberration yielding optimum visual performance: Evaluation of intraocular lenses using adaptive optics simulation

PubMed Central

Werner, John S.; Elliott, Sarah L.; Choi, Stacey S.; Doble, Nathan

2009-01-01

PURPOSE To evaluate the influence of spherical aberration on contrast sensitivity using adaptive optics. SETTING Vision Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California, Davis Medical Center, Sacramento, California, USA. METHODS Contrast sensitivity at 8 cycles per degree was evaluated using an adaptive optics system that permitted aberrations to be measured with a Shack-Hartman wavefront sensor and controlled by a 109 actuator continuous-surface deformable mirror that was at a plane conjugate to the observer’s pupil. Vertical Gabor patches were viewed through a 6.3 mm diameter pupil conjugate aperture. Contrast sensitivity was measured with the deformable mirror set to produce 1 of 5 spherical aberration profiles (−0.2 to +0.2 μm). Contrast sensitivity over the range of spherical aberration was fitted with a polynomial function. RESULTS Three observers (age 21 to 24 years) participated. The measured total mean spherical aberration resulting from the spherical aberration profiles produced by the deformable mirror was between −0.15 μm and +0.25 μm. The peak contrast sensitivity of this function for the 3 observers combined occurred at +0.06 μm of spherical aberration. The peak contrast sensitivity was also achieved with positive spherical aberration for observer (mean 0.09). CONCLUSION There was intersubject variability in the measurements; however, the average visual performance was best with the introduction of a small positive spherical aberration. PMID:19545813

Study of positive and negative feedback sensitivity in psychosis using the Wisconsin Card Sorting Test.

PubMed

Farreny, Aida; Del Rey-Mejías, Ángel; Escartin, Gemma; Usall, Judith; Tous, Núria; Haro, Josep Maria; Ochoa, Susana

2016-07-01

Schizophrenia involves marked motivational and learning deficits that may reflect abnormalities in reward processing. The purpose of this study was to examine positive and negative feedback sensitivity in schizophrenia using computational modeling derived from the Wisconsin Card Sorting Test (WCST). We also aimed to explore feedback sensitivity in a sample with bipolar disorder. Eighty-three individuals with schizophrenia and 27 with bipolar disorder were included. Demographic, clinical and cognitive outcomes, together with the WCST, were considered in both samples. Computational modeling was performed using the R syntax to calculate 3 parameters based on trial-by-trial execution on the WCST: reward sensitivity (R), punishment sensitivity (P), and choice consistency (D). The associations between outcome variables and the parameters were investigated. Positive and negative sensitivity showed deficits, but P parameter was clearly diminished in schizophrenia. Cognitive variables, age, and symptoms were associated with R, P, and D parameters in schizophrenia. The sample with bipolar disorder would show cognitive deficits and feedback abnormalities to a lesser extent than individuals with schizophrenia. Negative feedback sensitivity demonstrated greater deficit in both samples. Idiosyncratic cognitive requirements in the WCST might introduce confusion when supposing model-free reinforcement learning. Negative symptoms of schizophrenia were related to lower feedback sensitivity and less goal-directed patterns of choice. Copyright © 2016 Elsevier Inc. All rights reserved.

Neutral vs positive oral contrast in diagnosing acute appendicitis with contrast-enhanced CT: sensitivity, specificity, reader confidence and interpretation time

PubMed Central

Naeger, D M; Chang, S D; Kolli, P; Shah, V; Huang, W; Thoeni, R F

2011-01-01

Objective The study compared the sensitivity, specificity, confidence and interpretation time of readers of differing experience in diagnosing acute appendicitis with contrast-enhanced CT using neutral vs positive oral contrast agents. Methods Contrast-enhanced CT for right lower quadrant or right flank pain was performed in 200 patients with neutral and 200 with positive oral contrast including 199 with proven acute appendicitis and 201 with other diagnoses. Test set disease prevalence was 50%. Two experienced gastrointestinal radiologists, one fellow and two first-year residents blindly assessed all studies for appendicitis (2000 readings) and assigned confidence scores (1=poor to 4=excellent). Receiver operating characteristic (ROC) curves were generated. Total interpretation time was recorded. Each reader's interpretation with the two agents was compared using standard statistical methods. Results Average reader sensitivity was found to be 96% (range 91–99%) with positive and 95% (89–98%) with neutral oral contrast; specificity was 96% (92–98%) and 94% (90–97%). For each reader, no statistically significant difference was found between the two agents (sensitivities p-values >0.6; specificities p-values>0.08), in the area under the ROC curve (range 0.95–0.99) or in average interpretation times. In cases without appendicitis, positive oral contrast demonstrated improved appendix identification (average 90% vs 78%) and higher confidence scores for three readers. Average interpretation times showed no statistically significant differences between the agents. Conclusion Neutral vs positive oral contrast does not affect the accuracy of contrast-enhanced CT for diagnosing acute appendicitis. Although positive oral contrast might help to identify normal appendices, we continue to use neutral oral contrast given its other potential benefits. PMID:20959365

Diagnostic reliability of 3.0-T MRI for detecting osseous abnormalities of the temporomandibular joint.

PubMed

Sawada, Kunihiko; Amemiya, Toshihiko; Hirai, Shigenori; Hayashi, Yusuke; Suzuki, Toshihiro; Honda, Masahiko; Sisounthone, Johnny; Matsumoto, Kunihito; Honda, Kazuya

2018-01-01

We compared the diagnostic reliability of 3.0-T magnetic resonance imaging (MRI) for detection of osseous abnormalities of the temporomandibular joint (TMJ) with that of the gold standard, cone-beam computed tomography (CBCT). Fifty-six TMJs were imaged with CBCT and MRI, and images of condyles and fossae were independently assessed for the presence of osseous abnormalities. The accuracy, sensitivity, and specificity of 3.0-T MRI were 0.88, 1.0, and 0.73, respectively, in condyle evaluation and 0.91, 0.75, and 0.95 in fossa evaluation. The McNemar test showed no significant difference (P > 0.05) between MRI and CBCT in the evaluation of osseous abnormalities in condyles and fossae. The present results indicate that 3.0-T MRI is equal to CBCT in the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

[Congenital abnormalities of the aorta in children and adolescents].

PubMed

Eichhorn, J G; Ley, S

2007-11-01

Aortic abnormalities are common cardiovascular malformations accounting for 15-20% of all congenital heart disease. Ultrafast CT and MR imaging are noninvasive, accurate and robust techniques that can be used in the diagnosis of aortic malformations. While their sensitivity in detecting vascular abnormalities seems to be as good as that of conventional catheter angiocardiography, at over 90%, they are superior in the diagnosis of potentially life-threatening complications, such as tracheal, bronchial, or esophageal compression. It has been shown that more than 80% of small children with aortic abnormalities benefit directly from the use of noninvasive imaging: either cardiac catheterization is no longer necessary or radiation doses and periods of general anesthesia for interventional catheterization procedures can be much reduced. The most important congenital abnormalities of the aorta in children and adolescents are presented with reference to examples, and the value of CT and MR angiography is documented.

Abnormal laughter-like vocalisations replacing speech in primary progressive aphasia

PubMed Central

Rohrer, Jonathan D.; Warren, Jason D.; Rossor, Martin N.

2009-01-01

We describe ten patients with a clinical diagnosis of primary progressive aphasia (PPA) (pathologically confirmed in three cases) who developed abnormal laughter-like vocalisations in the context of progressive speech output impairment leading to mutism. Failure of speech output was accompanied by increasing frequency of the abnormal vocalisations until ultimately they constituted the patient's only extended utterance. The laughter-like vocalisations did not show contextual sensitivity but occurred as an automatic vocal output that replaced speech. Acoustic analysis of the vocalisations in two patients revealed abnormal motor features including variable note duration and inter-note interval, loss of temporal symmetry of laugh notes and loss of the normal decrescendo. Abnormal laughter-like vocalisations may be a hallmark of a subgroup in the PPA spectrum with impaired control and production of nonverbal vocal behaviour due to disruption of fronto-temporal networks mediating vocalisation. PMID:19435636

Abnormal laughter-like vocalisations replacing speech in primary progressive aphasia.

PubMed

Rohrer, Jonathan D; Warren, Jason D; Rossor, Martin N

2009-09-15

We describe ten patients with a clinical diagnosis of primary progressive aphasia (PPA) (pathologically confirmed in three cases) who developed abnormal laughter-like vocalisations in the context of progressive speech output impairment leading to mutism. Failure of speech output was accompanied by increasing frequency of the abnormal vocalisations until ultimately they constituted the patient's only extended utterance. The laughter-like vocalisations did not show contextual sensitivity but occurred as an automatic vocal output that replaced speech. Acoustic analysis of the vocalisations in two patients revealed abnormal motor features including variable note duration and inter-note interval, loss of temporal symmetry of laugh notes and loss of the normal decrescendo. Abnormal laughter-like vocalisations may be a hallmark of a subgroup in the PPA spectrum with impaired control and production of nonverbal vocal behaviour due to disruption of fronto-temporal networks mediating vocalisation.

Current controversies in prenatal diagnosis 2: Cell-free DNA prenatal screening should be used to identify all chromosome abnormalities.

PubMed

Chitty, Lyn S; Hudgins, Louanne; Norton, Mary E

2018-02-01

Noninvasive prenatal testing (NIPT) using cell-free DNA (cfDNA) from maternal serum has been clinically available since 2011. This technology has revolutionized our ability to screen for the common aneuploidies trisomy 21 (Down syndrome), trisomy 18, and trisomy 13. More recently, clinical laboratories have offered screening for other chromosome abnormalities including sex chromosome abnormalities and copy number variants (CNV) without little published data on the sensitivity, specificity, and positive predictive value. In this debate, the pros and cons of performing prenatal screening via cfDNA for all chromosome abnormalities is discussed. At the time of the debate in 2017, the general consensus was that the literature does not yet support using this technology to screen for all chromosome abnormalities and that education is key for both providers and the patients so that the decision-making process is as informed as possible. © 2018 John Wiley & Sons, Ltd.

Contrast adaptation induced by defocus - a possible error signal for emmetropization?

PubMed

Ohlendorf, Arne; Schaeffel, Frank

2009-01-01

To describe some features of contrast adaptation as induced by imposed positive or negative defocus. To study its time course and selectivity for the sign of the imposed defocus. Contrast adaptation, CA (here referred to as any change in supra-threshold contrast sensitivity) was induced by presenting a movie to the subjects on a computer screen at 1m distance for 10min, while the right eye was defocused by a trial lens (+4D (n=25); -4D (n=10); -2D (n=11 subjects). The PowerRefractor was used to track accommodation binocularly. Contrast sensitivity at threshold was measured by a method of adjustment with a Gabor patch of 1deg angular subtense, filled with 3.22cyc/deg sine wave grating presented on a computer screen at 1m distance on gray background (33cd/m(2)). Supra-threshold contrast sensitivity was quantified by an interocular contrast matching task, in which the subject had to match the contrast of the sine wave grating seen with the right eye with the contrast of a grating with fixed contrast of 0.1. (1) Contrast sensitivity thresholds were not lowered by previous viewing of defocused movies. (2) By wearing positive lenses, the supra-threshold contrast sensitivity in the right eye was raised by about 30% and remained elevated for at least 2min until baseline was reached after about 5min. (3) CA was induced only by positive, but not by negative lenses, even after the distance of the computer screen was taken into account (1m, equivalent to +1D). In five subjects, binocular accommodation was tracked over the full adaptation period. Accommodation appeared to focus the eye not wearing a lens, but short transient switches in focus to the lens wearing eye could not be entirely excluded. Transient contrast adaptation was found at 3.22cyc/deg when positive lenses were worn but not with negative lenses. This asymmetry is intriguing. While it may represent an epiphenomenon of physiological optics, further experiments are necessary to determine whether it could also trace back to differences in CA with defocus of different sign.

Floaters and reduced contrast sensitivity after successful pharmacologic vitreolysis with ocriplasmin.

PubMed

Khoshnevis, Matin; Nguyen-Cuu, Jeannie; Sebag, J

2016-12-01

To describe the onset of floaters and reduction in contrast sensitivity (CS) following successful pharmacologic vitreolysis with ocriplasmin for the treatment of vitreo-macular traction (VMT) in a patient with previously normal CS. A 65-year-old woman with a past ocular history of normal visual acuity (VA = 20/26) and contrast sensitivity (1.81% Weber) presents with a 4-month history of distortions. VA decreased to 20/40 and Optical Coherence Tomography (OCT) demonstrated VMT. Pharmacologic vitreolysis was performed with intravitreal ocriplasmin. Ten weeks later the patient complained of floaters and was found to have a PVD and complete resolution of VMT. VA was still 20/40, but contrast sensitivity decreased by more than 100% to 3.77%Weber. After 6 months of attempted coping, this did not improve, so limited vitrectomy was performed. Post-operative VA = 20/26 and CS improved by 46% from 3.77%W to 2.03%W (normal). and importance: This case highlights a little discussed consequence of PVD induction by successful pharmacologic vitreolysis - the development of clinically significant floaters. The resulting reduction of contrast sensitivity was normalized by limited vitrectomy, strongly suggesting that the detached vitreous was the cause.

Internal noise sources limiting contrast sensitivity.

PubMed

Silvestre, Daphné; Arleo, Angelo; Allard, Rémy

2018-02-07

Contrast sensitivity varies substantially as a function of spatial frequency and luminance intensity. The variation as a function of luminance intensity is well known and characterized by three laws that can be attributed to the impact of three internal noise sources: early spontaneous neural activity limiting contrast sensitivity at low luminance intensities (i.e. early noise responsible for the linear law), probabilistic photon absorption at intermediate luminance intensities (i.e. photon noise responsible for de Vries-Rose law) and late spontaneous neural activity at high luminance intensities (i.e. late noise responsible for Weber's law). The aim of this study was to characterize how the impact of these three internal noise sources vary with spatial frequency and determine which one is limiting contrast sensitivity as a function of luminance intensity and spatial frequency. To estimate the impact of the different internal noise sources, the current study used an external noise paradigm to factorize contrast sensitivity into equivalent input noise and calculation efficiency over a wide range of luminance intensities and spatial frequencies. The impact of early and late noise was found to drop linearly with spatial frequency, whereas the impact of photon noise rose with spatial frequency due to ocular factors.

Abnormal global processing along the dorsal visual pathway in autism: a possible mechanism for weak visuospatial coherence?

PubMed

Pellicano, Elizabeth; Gibson, Lisa; Maybery, Murray; Durkin, Kevin; Badcock, David R

2005-01-01

Frith and Happe (Frith, U., & Happe, F. (1994). Autism: Beyond theory of mind. Cognition, 50, 115-132) argue that individuals with autism exhibit 'weak central coherence': an inability to integrate elements of information into coherent wholes. Some authors have speculated that a high-level impairment might be present in the dorsal visual pathway in autism, and furthermore, that this might account for weak central coherence, at least at the visuospatial level. We assessed the integrity of the dorsal visual pathway in children diagnosed with an autism spectrum disorder (ASD), and in typically developing children, using two visual tasks, one examining functioning at higher levels of the dorsal cortical stream (Global Dot Motion (GDM)), and the other assessing lower-level dorsal stream functioning (Flicker Contrast Sensitivity (FCS)). Central coherence was tested using the Children's Embedded Figures Test (CEFT). Relative to the typically developing children, the children with ASD had shorter CEFT latencies and higher GDM thresholds but equivalent FCS thresholds. Additionally, CEFT latencies were inversely related to GDM thresholds in the ASD group. These outcomes indicate that the elevated global motion thresholds in autism are the result of high-level impairments in dorsal cortical regions. Weak visuospatial coherence in autism may be in the form of abnormal cooperative mechanisms in extra-striate cortical areas, which might contribute to differential performance when processing stimuli as Gestalts, including both dynamic (i.e., global motion perception) and static (i.e., disembedding performance) stimuli.

Effect of Ginkgo biloba on visual field and contrast sensitivity in Chinese patients with normal tension glaucoma: a randomized, crossover clinical trial.

PubMed

Guo, Xinxing; Kong, Xiangbin; Huang, Rui; Jin, Ling; Ding, Xiaohu; He, Mingguang; Liu, Xing; Patel, Mehul Chimanlal; Congdon, Nathan G

2014-01-07

We evaluated the effect of ginkgo biloba extract on visual field defect and contrast sensitivity in a Chinese cohort with normal tension glaucoma. In this prospective, randomized, placebo-controlled crossover study, patients newly diagnosed with normal tension glaucoma, either in a tertiary glaucoma clinic (n = 5) or in a cohort undergoing routine general physical examinations in a primary care clinic (n = 30), underwent two 4-week phases of treatment, separated by a washout period of 8 weeks. Randomization determined whether ginkgo biloba extract (40 mg, 3 times per day) or placebo (identical-appearing tablets) was received first. Primary outcomes were change in contrast sensitivity and mean deviation on 24-2 SITA standard visual field testing, while secondary outcomes included IOP and self-reported adverse events. A total of 35 patients with mean age 63.7 (6.5) years were randomized to the ginkgo biloba extract-placebo (n = 18) or the placebo-ginkgo biloba extract (n = 17) sequence. A total of 28 patients (80.0%, 14 in each group) who completed testing did not differ at baseline in age, sex, visual field mean deviation, contrast sensitivity, IOP, or blood pressure. Changes in visual field and contrast sensitivity did not differ by treatment received or sequence (P > 0.2 for all). Power to have detected a difference in mean defect as large as previously reported was 80%. In contrast to some previous reports, ginkgo biloba extract treatment had no effect on mean defect or contrast sensitivity in this group of normal tension glaucoma patients. (http://www.chictr.org number, ChiCTR-TRC-08000724).

Non-contrast MRI diagnosis of adhesive capsulitis of the shoulder.

PubMed

Chi, Andrew S; Kim, John; Long, Suzanne S; Morrison, William B; Zoga, Adam C

To investigate non-contrast MRI findings of clinical adhesive capsulitis. 31 non-contrast, non-arthrographic, shoulder MRIs were evaluated for coracohumeral ligament thickness, rotator interval infiltration, and axillary recess thickening/edema. In detection of adhesive capsulitis, sensitivity is 76.7% and specificity is 53.3% for coracohumeral ligament thickening, sensitivity is 66.7% and specificity is 55.2% for coracohumeral ligament thickening and rotator interval infiltration, and sensitivity is 23.3% and specificity is 86.7% for coracohumeral ligament thickening, rotator interval infiltration, and axillary recess thickening/edema. Adhesive capsulitis can be accurately diagnosed on non-contrast MRI shoulder examinations with appropriate clinical criteria without direct MR arthrography. Copyright © 2017 Elsevier Inc. All rights reserved.

Sensitivity and specificity of a urinary screening test used in an emergency setting to detect abnormal first trimester pregnancies.

PubMed

Teixeira, João L G; Rabaioli, Paola; Savaris, Ricardo F

2015-01-01

To evaluate the performance of a commercial urinary test to screen for abnormal first trimester pregnancies in women presenting to an emergency room. In this prospective observational cohort, women with a confirmed first trimester pregnancy (gestational age <12 weeks) provided a urine sample for diagnosing the viability of their gestation. Pregnancy viability and location testing were confirmed by ultrasound and/or laparoscopy. From 815 eligible patients for the study, 12 were excluded for not having a confirmed pregnancy (n = 6) or were lost to follow-up (n = 6). A total of 803 patients underwent testing and completed follow-up. The pretest probability of an abnormal pregnancy was 44% (9% for ectopic pregnancy and 35% for miscarriage). The test had the following parameters to identify an abnormal first-trimester pregnancy (sensitivity, 13%; 95% confidence interval [CI], 10-17; specificity, 82%; 95% CI, 78-86; positive predictive value, 36; 95% CI, 28-46; negative predictive value, 54; 95% CI, 50-58; accuracy, 47%; positive likelihood ratio, 0.74; 95% CI, 0.53-1.03; negative likelihood ratio, 1.06; 95% CI, 1-1.12). The reproducibility of the test in our study was high (kappa index between readers, 0.89; 95% CI, 0.77-1). In our emergency setting, we were not able to confirm that the commercial test is adequate to detect or exclude an abnormal first-trimester pregnancy. Copyright © 2015 Elsevier Inc. All rights reserved.

Reduced laser-evoked potential habituation detects abnormal central pain processing in painful radiculopathy patients.

PubMed

Hüllemann, P; von der Brelie, C; Manthey, G; Düsterhöft, J; Helmers, A K; Synowitz, M; Baron, R

2017-05-01

Repetitive painful laser stimuli lead to physiological laser-evoked potential (LEP) habituation, measurable by a decrement of the N2/P2 amplitude. The time course of LEP-habituation is reduced in the capsaicin model for peripheral and central sensitization and in patients with migraine and fibromyalgia. In the present investigation, we aimed to assess the time course of LEP-habituation in a neuropathic pain syndrome, i.e. painful radiculopathy. At the side of radiating pain, four blocks of 25 painful laser stimuli each were applied to the ventral thigh at the L3 dermatome in 27 patients with painful radiculopathy. Inclusion criteria were (1) at least one neurological finding of radiculopathy, (2) low back pain with radiation into the foot and (3) a positive one-sided compression of the L5 and/or S1 root in the MRI. The time course of LEP-habituation was compared to 20 healthy height and age matched controls. Signs of peripheral (heat hyperalgesia) and central sensitization (dynamic mechanical allodynia and hyperalgesia) at the affected L5 or S1 dermatome were assessed with quantitative sensory testing. Painful radiculopathy patients showed decreased LEP-habituation compared to controls. Patients with signs of central sensitization showed a more prominent LEP-habituation decrease within the radiculopathy patient group. Laser-evoked potential habituation is reduced in painful radiculopathy patients, which indicates an abnormal central pain processing. Central sensitization seems to be a major contributor to abnormal LEP habituation. The LEP habituation paradigm might be useful as a clinical tool to assess central pain processing alterations in nociceptive and neuropathic pain conditions. Abnormal central pain processing in neuropathic pain conditions may be revealed with the laser-evoked potential habituation paradigm. In painful radiculopathy patients, LEP-habituation is reduced compared to healthy controls. © 2017 European Pain Federation - EFIC®.

Imaging for Polyps and Leiomyomas in Women With Abnormal Uterine Bleeding: A Systematic Review.

PubMed

Maheux-Lacroix, Sarah; Li, Fiona; Laberge, Philippe Y; Abbott, Jason

2016-12-01

To evaluate the accuracy of saline infusion sonohysterography in comparison with transvaginal ultrasonography for diagnosing polyps and submucosal leiomyomas in women with abnormal uterine bleeding. We searched the databases MEDLINE, EMBASE, CENTRAL, and ClinicalTrials.gov as well as citations and reference lists to the end of November 2015. Two authors screened 5,347 citations for eligibility. We included randomized controlled trials or prospective cohort studies published in English, assessing the accuracy of saline infusion sonohysterography and transvaginal ultrasonography for diagnosing polyps and submucosal leiomyomas in women with abnormal uterine bleeding. We considered studies using histopathologic specimens obtained at either hysteroscopy or hysterectomy as criterion standard. Twenty-five studies were eligible. Two authors extracted data and assessed the quality of included studies. Bivariate random-effects models were used to compare the different tests and evaluate sources of heterogeneity. Saline infusion sonohysterography was superior to transvaginal ultrasonography with pooled sensitivity and specificity of 0.92 and 0.89 compared with 0.64 and 0.90, respectively (P<.001). Transvaginal ultrasound sensitivity for diagnosing polyps was particularly low (0.51). Saline infusion sonohysterography was also compared with hysteroscopy in seven studies and had similar sensitivity but inferior specificity (0.93 and 0.83 compared with 0.95 and 0.90, respectively, P=.007). All three procedures were well-tolerated by women. Saline infusion sonohysterography was successfully completed in 95% of women. Technical variations such as the use of balloon catheters were not found to affect diagnostic accuracy. Transvaginal ultrasonography lacks sensitivity to be used alone to exclude the presence of polyps and leiomyomas in women with abnormal uterine bleeding. Although less specific than hysteroscopy, saline infusion sonohysterography offers a similar detection rate and permits concomitant visualization of the ovaries and myometrium. Cost, convenience, and tolerability of different imaging techniques require further evaluation. PROSPERO International prospective register of systematic reviews, http://www.crd.york.ac.uk/PROSPERO, CRD42016034005.

Evaluation of gastro-oesophageal reflux disease in wheezy infants using 24-h oesophageal combined impedance and pH monitoring.

PubMed

Abdallah, Ahmed; El-Desoky, Tarek; Fathi, Khalid; Fawzi Elkashef, Wagdi; Zaki, Ahmed

2017-06-01

Gastro-oesophageal reflux disease (GERD) is incriminated as a cause of non-asthmatic infantile wheeze. To date, no diagnostic test is considered standard for GERD-related airway reflux diagnosis. Oesophageal combined multiple channel intraluminal impedance and pH (MII-pH) monitoring is proposed to be a sensitive tool for evaluation of all GERD including infantile wheeze. We aimed to determine the GERD prevalence amongst wheezy infants in the first year of life using combined MII-pH versus pH monitoring alone and evaluate the sensitivity and specificity of objective MII-pH monitoring parameters in GERD-associated infantile wheeze diagnosis compared to those of lipid-laden macrophage index (LLMI). Thirty-eight wheezy infants below 1year of age were evaluated for GERD using oesophageal combined MII-pH monitoring and LLMI. Totally, 60.5% of cases had abnormal MII-pH; only 7.9% of them had abnormal pH monitoring. LLMI was significantly higher in wheezy infants with abnormal MII-pH than infants with normal MII-pH monitoring (112±88 versus 70±48; P=0.036). The current definitions of abnormal MII-pH study, reflux index≥10% and distal reflux episodes≥100, had low sensitivity (23%) but high specificity (100% and 96%, respectively) in GERD-related aspiration diagnosis defined by LLMI≥100. Using ROC curves, bolus contact time≥2.4% and proximal reflux episodes≥46 had 61% and 54% sensitivity and 64% and 76% specificity, respectively, in GERD-related aspiration diagnosis. Combined MII-pH is superior to pH monitoring in reflux-associated infantile wheeze diagnosis. Objective data including proximal reflux episodes and bolus contact time should be combined with the current parameters used in reflux-associated infantile wheeze diagnosis. Copyright © 2017 Pan-Arab Association of Gastroenterology. Published by Elsevier B.V. All rights reserved.

A novel non-contrast-enhanced MRA using silent scan for evaluation of brain arteriovenous malformation: A case report and review of literature.

PubMed

Moon, Jin Il; Baek, Hye Jin; Ryu, Kyeong Hwa; Park, Hyun

2017-11-01

Brain arteriovenous malformations (AVMs) are congenital vascular abnormalities involving abnormal connections between arteries and veins. In clinical practice, imaging studies help evaluate feeding arteries, niduses, draining venous systems, and coexisting complications in patients with brain AVM. They also have an impact on decision-making regarding clinical management. We applied a novel non-contrast-enhanced MR angiography (MRA) technique, termed "silent MRA," for evaluating an incidental brain AVM. Here, we describe the clinical case with radiological review and highlight the technical background and clinical usefulness of silent MRA. A 60-year-old woman underwent neuroimaging study including MRA to evaluate intracranial cause of headache. The brain AVM, including its nidus and draining veins, was conspicuously delineated on silent MRA images; these findings correlated well with conventional angiographic findings. The patient did not receive interventional or surgical treatment. The patient is being followed up regularly at the outpatient department. The silent MRA can be a suitable imaging modality for repeated follow-up evaluation for not only brain AVMs but also various intracranial vascular diseases without the use of contrast materials.

Utility of screening ultrasound after first febrile UTI among patients with clinically significant vesicoureteral reflux.

PubMed

Massanyi, Eric Z; Preece, Janae; Gupta, Angela; Lin, Susan M; Wang, Ming-Hsien

2013-10-01

To assess the sensitivity and negative predictive value (NPV) of screening renal and bladder ultrasound (RBUS) after initial febrile urinary tract infection (UTI) among patients with clinically significant vesicoureteral reflux (VUR). A retrospective review was performed of all children <2 years of age who presented with a febrile UTI between 2004 and 2011. The sensitivity and NPV of initial RBUS was calculated among patients who were found to have high-grade (IV-V) VUR. Additionally, initial RBUS among patients with evidence of photopenia on dimercaptosuccinic acid (DMSA) scan or who underwent surgical intervention were reviewed. One hundred forty-four patients with febrile UTI were identified; available RBUS, voiding cystourethrogram (VCUG), and DMSA results for each kidney were reviewed. One hundred fifty-eight kidneys had evidence of VUR on VCUG, and initial RBUS demonstrated abnormality in 25 (sensitivity 0.17). Forty-five kidneys had high-grade VUR and RBUS revealed abnormality in 16 (sensitivity 0.36). One hundred seventy-eight kidneys had no evidence of abnormality on initial RBUS, and 136 (76%) were found to have VUR (NPV 0.24), of which 31 had high-grade VUR (NPV 0.83). Seven kidneys had scarring on DMSA and initial RBUS was normal in 4 (57%). Twelve of 19 patients (63%) who eventually underwent surgical intervention had a normal initial RBUS. RBUS has poor sensitivity and NPV for detecting high-grade VUR in patients <2 years who present with a febrile UTI. A significant number of patients who were diagnosed with high-grade VUR, renal scarring, or underwent surgical correction of VUR had a negative screening RBUS. Copyright © 2013 Elsevier Inc. All rights reserved.

Sensitivity and specificity of General Movements Assessment for diagnostic accuracy of detecting cerebral palsy early in an Australian context.

PubMed

Morgan, Catherine; Crowle, Cathryn; Goyen, Traci-Anne; Hardman, Caroline; Jackman, Michelle; Novak, Iona; Badawi, Nadia

2016-01-01

The aim of this study was to calculate the sensitivity and specificity of the General Movements Assessment (GMA) for estimating diagnostic accuracy in detecting cerebral palsy (CP) in an Australian context by a newly established NSW rater network. A prospective longitudinal cross-sectional study was conducted. The GMA was blind-rated from conventional video by two independent certified raters, blinded to medical history. A third rater resolved disagreements. High-risk population screening for CP using the GMA during the fidgety period (12-20 weeks) was carried out in four neonatal intensive care units and one CP service over a 30-month period (2012-2013). Participants were 259 high-risk infants. Sensitivity and specificity values were calculated with true positives defined as a confirmed diagnosis of CP from a medical doctor. Of the 259 infants assessed, 1-year follow-up data were available for 187. Of these, n = 48 had absent fidgety (high risk for CP), n = 138 had normal fidgety (low risk for CP), and n = 1 had abnormal fidgety (high risk for a neurological disorder). Of the 48 with absent fidgety movements, 39 had received a diagnosis of CP by 18 months and another 6 had an abnormal outcome. Of the n = 138 normal fidgety cases, n = 99 cases had a normal outcome, n = 38 had an abnormal outcome but not CP, and n = 1 had CP. For detecting CP, we had a sensitivity of 98% and specificity of 94%. GMA was feasible in an Australian context and accurately identified CP with a sensitivity and specificity comparable with European standards and published neuroimaging data. © 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Performance of Anal Cytology Compared With High-Resolution Anoscopy and Histology in Women With Lower Anogenital Tract Neoplasia.

PubMed

Albuquerque, Andreia; Sheaff, Michael; Stirrup, Oliver; Cappello, Carmelina; Bowring, Julie; Cuming, Tamzin; de Masi, Anke; Rosenthal, Adam N; Nathan, Mayura

2018-04-05

Information on the performance of anal cytology in women who are high-risk for human papillomavirus-related lesions and the factors that might influence it are largely lacking. Evaluate the performance of anal cytology in women with lower anogenital tract neoplasia. retrospective study including all new referrals of women with a previous history of anogenital neoplasia, from January 2012 to July 2017, with concomitant anal cytology and high-resolution anoscopy with or without biopsies. 636 anal cytology samples and 323 biopsies were obtained from 278 women. Overall sensitivity and specificity of 'any abnormality' on anal cytology to predict 'any abnormality' in histology was 47% (95% CI 41-54%) and 84% (95% CI 73-91%), respectively. For detecting high-grade squamous intraepithelial lesions (HSIL)/cancer, sensitivity was 71% (95% CI 61-79%) and specificity was 73% (95% CI 66-79%). There was a poor concordance between cytological and histological grades (κ=0.147). Cytology had a higher sensitivity to predict HSIL/cancer in immunosuppressed vs. non-immunosuppressed patients (92% vs. 60%, P=0.002). The sensitivity for HSIL detection was higher when two or more quadrants were affected in comparison with only one (86% vs. 57%, P=0.006). A previous history of vulvar HSIL/cancer (OR 1.71, 1.08-2.73; P=0.023), immunosuppression (OR 1.88, 1.17-3.03; P=0.009) and concomitant genital HSIL/cancer (OR 2.51, 1.47-4.29; P=0.001) were risk factors for abnormal cytology. Patient characteristics can influence the performance of anal cytology in women. The sensitivity for detecting anal HSIL/cancer was higher in those immunosuppressed and with more extensive disease.

Antidiabetogenic Effects of Chromium Mitigate Hyperinsulinemia-Induced Cellular Insulin Resistance via Correction of Plasma Membrane Cholesterol Imbalance

PubMed Central

Horvath, Emily M.; Tackett, Lixuan; McCarthy, Alicia M.; Raman, Priya; Brozinick, Joseph T.; Elmendorf, Jeffrey S.

2008-01-01

Previously, we found that a loss of plasma membrane (PM) phosphatidylinositol 4,5-bisphosphate (PIP2)-regulated filamentous actin (F-actin) structure contributes to insulin-induced insulin resistance. Interestingly, we also demonstrated that chromium picolinate (CrPic), a dietary supplement thought to improve glycemic status in insulin-resistant individuals, augments insulin-regulated glucose transport in insulin-sensitive 3T3-L1 adipocytes by lowering PM cholesterol. Here, to gain mechanistic understanding of these separate observations, we tested the prediction that CrPic would protect against insulin-induced insulin resistance by improving PM features important in cytoskeletal structure and insulin sensitivity. We found that insulin-induced insulin-resistant adipocytes display elevated PM cholesterol with a reciprocal decrease in PM PIP2. This lipid imbalance and insulin resistance was corrected by the cholesterol-lowering action of CrPic. The PM lipid imbalance did not impair insulin signaling, nor did CrPic amplify insulin signal transduction. In contrast, PM analyses corroborated cholesterol and PIP2 interactions influencing cytoskeletal structure. Because extensive in vitro study documents an essential role for cytoskeletal capacity in insulin-regulated glucose transport, we next evaluated intact skeletal muscle from obese, insulin-resistant Zucker (fa/fa) rats. Because insulin resistance in these animals likely involves multiple mechanisms, findings that cholesterol-lowering restored F-actin cytoskeletal structure and insulin sensitivity to that witnessed in lean control muscle were striking. Also, experiments using methyl-β-cyclodextrin to shuttle cholesterol into or out of membranes respectively recapitulated the insulin-induced insulin-resistance and protective effects of CrPic on membrane/cytoskeletal interactions and insulin sensitivity. These data predict a PM cholesterol basis for hyperinsulinemia-associated insulin resistance and importantly highlight the reversible nature of this abnormality. PMID:18165437

Inwardly Rectifying K+ Currents in Cultured Oligodendrocytes from Rat Optic Nerve are Insensitive to pH.

PubMed

Pérez-Samartín, Alberto; Garay, Edith; Moctezuma, Juan Pablo H; Cisneros-Mejorado, Abraham; Sánchez-Gómez, María Victoria; Martel-Gallegos, Guadalupe; Robles-Martínez, Leticia; Canedo-Antelo, Manuel; Matute, Carlos; Arellano, Rogelio O

2017-09-01

Inwardly rectifying K + (Kir) channel expression signals at an advanced stage of maturation during oligodendroglial differentiation. Knocking down their expression halts the generation of myelin and produces severe abnormalities in the central nervous system. Kir4.1 is the main subunit involved in the tetrameric structure of Kir channels in glial cells; however, the precise composition of Kir channels expressed in oligodendrocytes (OLs) remains partially unknown, as participation of other subunits has been proposed. Kir channels are sensitive to H + ; thus, intracellular acidification produces Kir current inhibition. Since Kir subunits have differential sensitivity to H + , we studied the effect of intracellular acidification on Kir currents expressed in cultured OLs derived from optic nerves of 12-day-old rats. Unexpectedly, Kir currents in OLs (2-4 DIV) did not change within the pH range of 8.0-5.0, as observed when using standard whole-cell voltage-clamp recording or when preserving cytoplasmic components with the perforated patch-clamp technique. In contrast, low pH inhibited astrocyte Kir currents, which was consistent with the involvement of the Kir4.1 subunit. The H + -insensitivity expressed in OL Kir channels was not intrinsic because Kir cloning showed no difference in the sequence reported for the Kir4.1, Kir2.1, or Kir5.1 subunits. Moreover, when Kir channels were heterologously expressed in Xenopus oocytes they behaved as expected in their general properties and sensitivity to H + . It is therefore concluded that Kir channel H + -sensitivity in OLs is modulated through an extrinsic mechanism, probably by association with a modulatory component or by posttranslational modifications.

Brain Injury in Neonates with Complex Congenital Heart Disease: What Is the Predictive Value of MRI in the Fetal Period?

PubMed

Brossard-Racine, M; du Plessis, A; Vezina, G; Robertson, R; Donofrio, M; Tworetzky, W; Limperopoulos, C

2016-07-01

Brain injury in neonates with congenital heart disease is an important predictor of adverse neurodevelopmental outcome. Impaired brain development in congenital heart disease may have a prenatal origin, but the sensitivity and specificity of fetal brain MR imaging for predicting neonatal brain lesions are currently unknown. We sought to determine the value of conventional fetal MR imaging for predicting abnormal findings on neonatal preoperative MR imaging in neonates with complex congenital heart disease. MR imaging studies were performed in 103 fetuses with confirmed congenital heart disease (mean gestational age, 31.57 ± 3.86 weeks) and were repeated postnatally before cardiac surgery (mean age, 6.8 ± 12.2 days). Each MR imaging study was read by a pediatric neuroradiologist. Brain abnormalities were detected in 17/103 (16%) fetuses by fetal MR imaging and in 33/103 (32%) neonates by neonatal MR imaging. Only 9/33 studies with abnormal neonatal findings were preceded by abnormal findings on fetal MR imaging. The sensitivity and specificity of conventional fetal brain MR imaging for predicting neonatal brain abnormalities were 27% and 89%, respectively. Brain abnormalities detected by in utero MR imaging in fetuses with congenital heart disease are associated with higher risk of postnatal preoperative brain injury. However, a substantial proportion of anomalies on postnatal MR imaging were not present on fetal MR imaging; this result is likely due to the limitations of conventional fetal MR imaging and the emergence of new lesions that occurred after the fetal studies. Postnatal brain MR imaging studies are needed to confirm the presence of injury before open heart surgery. © 2016 by American Journal of Neuroradiology.

An Imaging Biomarker for Assessing Hepatic Function in Patients with Primary Sclerosing Cholangitis.

PubMed

Schulze, Jennifer; Lenzen, Henrike; Hinrichs, Jan B; Ringe, Burckhardt; Manns, Michael P; Wacker, Frank; Ringe, Kristina I

2018-05-15

We aimed to evaluate the potential of hepatobiliary phase magnetic resonance imaging (MRI) as parameter for assessment of hepatocellular function in patients with primary sclerosing cholangitis (PSC). We collected data from 111 patients (83 male, 28 female; median, 44 years old), from March 2012 through March 2016, with a confirmed diagnosis of PSC who underwent MRI evaluation before and after injection (hepatobiliary phase) of a hepatocyte-specific contrast agent (gadoxetate disodium). Signal intensities were measured in each liver segment. Mean relative enhancement values were calculated and correlated with findings from liver functions tests, prognostic scoring systems (model for end-stage liver disease [MELD] score; Mayo risk score; Amsterdam-Oxford-PSC score), abnormalities detected by endoscopic retrograde cholangiopancreatography (using the Amsterdam cholangiographic classification system), and clinical endpoints (liver transplantation, cholangiocarcinoma, liver-related death). Our primary aim was to associate relative enhancement values with liver function and patient outcomes. Most patients had moderate-stage disease and had intermediate levels of risk (median MELD score, 8 and median Mayo score, 0.27). Clinical endpoints were reached by 21 patients (6 developed cholangiocarcinoma, 8 underwent liver transplantation, and 7 patients died). The highest levels of correlations were observed for relative enhancement 20 min after contrast injection and level of alkaline phosphatase (r= -0.636), bilirubin (r= -0.646), albumin (r= 0.538); as well as international normalized ratio (r=0.456); MELD score (r= -0.587); Mayo risk score (r= -0.535), and Amsterdam-Oxford model score (r= -0.595) (P<.0001). Relative enhancement correlated with all clinical endpoints (all P<.05). A cutoff relative enhancement value of 0.65 identified patients with a clinical endpoint with 73.9% sensitivity 92.9% specificity (area under the receiver operating characteristic curve, 0.901; likelihood ratio, 10.34; P<.0001). In an analysis of 111 patients with PSC, we found MRI-measured relative enhancement, using a hepatocyte-specific contrast agent, to identify patients with clinical outcomes with 73.9% sensitivity 92.9% specificity. Long-term, multicenter studies are needed to further evaluate this marker of PSC progression. Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

Positron emission mammography (PEM): Effect of activity concentration, object size, and object contrast on phantom lesion detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacDonald, Lawrence R.; Wang, Carolyn L.; Eissa, Marna

2012-10-15

Purpose: To characterize the relationship between lesion detection sensitivity and injected activity as a function of lesion size and contrast on the PEM (positron emission mammography) Flex Solo II scanner using phantom experiments. Methods: Phantom lesions (spheres 4, 8, 12, 16, and 20 mm diameter) were randomly located in uniform background. Sphere activity concentrations were 3 to 21 times the background activity concentration (BGc). BGc was a surrogate for injected activity; BGc ranged from 0.44-4.1 kBq/mL, corresponding to 46-400 MBq injections. Seven radiologists read 108 images containing zero, one, or two spheres. Readers used a 5-point confidence scale to scoremore » the presence of spheres. Results: Sensitivity was 100% for lesions {>=}12 mm under all conditions except for one 12 mm sphere with the lowest contrast and lowest BGc (60% sensitivity). Sensitivity was 100% for 8 mm spheres when either contrast or BGc was high, and 100% for 4 mm spheres only when both contrast and BGc were highest. Sphere contrast recovery coefficients (CRC) were 49%, 34%, 26%, 14%, and 2.8% for the largest to smallest spheres. Cumulative specificity was 98%. Conclusions: Phantom lesion detection sensitivity depends more on sphere size and contrast than on BGc. Detection sensitivity remained {>=}90% for injected activities as low as 100 MBq, for lesions {>=}8 mm. Low CRC in 4 mm objects results in moderate detection sensitivity even for 400 MBq injected activity, making it impractical to optimize injected activity for such lesions. Low CRC indicates that when lesions <8 mm are observed on PEM images they are highly tracer avid with greater potential of clinical significance. High specificity (98%) suggests that image statistical noise does not lead to false positive findings. These results apply to the 85 mm thick object used to obtain them; lesion detectability should be better (worse) for thinner (thicker) objects based on the reduced (increased) influence of photon attenuation.« less

Assessing Binocular Interaction in Amblyopia and Its Clinical Feasibility

PubMed Central

Kwon, MiYoung; Lu, Zhong-Lin; Miller, Alexandra; Kazlas, Melanie; Hunter, David G.; Bex, Peter J.

2014-01-01

Purpose To measure binocular interaction in amblyopes using a rapid and patient-friendly computer-based method, and to test the feasibility of the assessment in the clinic. Methods Binocular interaction was assessed in subjects with strabismic amblyopia (n = 7), anisometropic amblyopia (n = 6), strabismus without amblyopia (n = 15) and normal vision (n = 40). Binocular interaction was measured with a dichoptic phase matching task in which subjects matched the position of a binocular probe to the cyclopean perceived phase of a dichoptic pair of gratings whose contrast ratios were systematically varied. The resulting effective contrast ratio of the weak eye was taken as an indicator of interocular imbalance. Testing was performed in an ophthalmology clinic under 8 mins. We examined the relationships between our binocular interaction measure and standard clinical measures indicating abnormal binocularity such as interocular acuity difference and stereoacuity. The test-retest reliability of the testing method was also evaluated. Results Compared to normally-sighted controls, amblyopes exhibited significantly reduced effective contrast (∼20%) of the weak eye, suggesting a higher contrast requirement for the amblyopic eye compared to the fellow eye. We found that the effective contrast ratio of the weak eye covaried with standard clincal measures of binocular vision. Our results showed that there was a high correlation between the 1st and 2nd measurements (r = 0.94, p<0.001) but without any significant bias between the two. Conclusions Our findings demonstrate that abnormal binocular interaction can be reliably captured by measuring the effective contrast ratio of the weak eye and quantitative assessment of binocular interaction is a quick and simple test that can be performed in the clinic. We believe that reliable and timely assessment of deficits in a binocular interaction may improve detection and treatment of amblyopia. PMID:24959842

High contrast sensitivity for visually guided flight control in bumblebees.

PubMed

Chakravarthi, Aravin; Kelber, Almut; Baird, Emily; Dacke, Marie

2017-12-01

Many insects rely on vision to find food, to return to their nest and to carefully control their flight between these two locations. The amount of information available to support these tasks is, in part, dictated by the spatial resolution and contrast sensitivity of their visual systems. Here, we investigate the absolute limits of these visual properties for visually guided position and speed control in Bombus terrestris. Our results indicate that the limit of spatial vision in the translational motion detection system of B. terrestris lies at 0.21 cycles deg -1 with a peak contrast sensitivity of at least 33. In the perspective of earlier findings, these results indicate that bumblebees have higher contrast sensitivity in the motion detection system underlying position control than in their object discrimination system. This suggests that bumblebees, and most likely also other insects, have different visual thresholds depending on the behavioral context.

Withaferin A is a Leptin Sensitizer with Strong Anti-Diabetic Properties in Mice

PubMed Central

Lee, Jaemin; Liu, Junli; Feng, Xudong; Salazar Hernández, Mario Andrés; Mucka, Patrick; Ibi, Dorina; Choi, Jae Won; Ozcan, Umut

2018-01-01

The increasing global prevalence of obesity and its associated disorders point to an urgent need for the development of novel and effective therapeutic strategies that induce healthy weight loss. Obesity is characterized by hyperleptinemia and central leptin resistance. In an attempt to identify compounds that could reverse leptin resistance and thus promote weight loss, we analyzed a library of small molecules with mRNA expression profiles similar to that of celastrol, a naturally-occurring compound we previously identified as a leptin sensitizer. By this process we identified another natural compound, withaferin A, that also acts as a leptin sensitizer. We found that withaferin A treatment of diet-induced obese mice resulted in a 20-25% reduction of body weight, while also decreasing obesity-associated abnormalities including hepatic steatosis. Withaferin A marginally affects the body weight of ob/ob and db/db mice, which are both deficient in leptin signaling. In addition, withaferin A, unlike celastrol, has beneficial effects on glucose metabolism independently from its leptin-sensitizing effect. Our results show that the metabolic abnormalities of diet-induced obesity can be mitigated by sensitizing animals to endogenous leptin, and indicate that withaferin A is a potential leptin sensitizer with additional anti-diabetic actions. PMID:27479085

Withaferin A is a leptin sensitizer with strong antidiabetic properties in mice.

PubMed

Lee, Jaemin; Liu, Junli; Feng, Xudong; Salazar Hernández, Mario Andrés; Mucka, Patrick; Ibi, Dorina; Choi, Jae Won; Ozcan, Umut

2016-09-01

The increasing global prevalence of obesity and its associated disorders points to an urgent need for the development of novel and effective therapeutic strategies that induce healthy weight loss. Obesity is characterized by hyperleptinemia and central leptin resistance. In an attempt to identify compounds that could reverse leptin resistance and thus promote weight loss, we analyzed a library of small molecules that have mRNA expression profiles similar to that of celastrol, a naturally occurring compound that we previously identified as a leptin sensitizer. Through this process, we identified another naturally occurring compound, withaferin A, that also acts as a leptin sensitizer. We found that withaferin-A treatment of mice with diet-induced obesity (DIO) resulted in a 20-25% reduction of body weight, while also decreasing obesity-associated abnormalities, including hepatic steatosis. Withaferin-A treatment marginally affected the body weight of ob/ob and db/db mice, both of which are deficient in leptin signaling. In addition, withaferin A, unlike celastrol, has beneficial effects on glucose metabolism that occur independently of its leptin-sensitizing effect. Our results show that the metabolic abnormalities of DIO can be mitigated by sensitizing animals to endogenous leptin, and they indicate that withaferin A is a potential leptin sensitizer with additional antidiabetic actions.

Multimodal noninvasive and invasive imaging of extracranial venous abnormalities indicative of CCSVI: Results of the PREMiSe pilot study

PubMed Central

2013-01-01

Background There is no established noninvasive or invasive diagnostic imaging modality at present that can serve as a ‘gold standard’ or “benchmark” for the detection of the venous anomalies, indicative of chronic cerebrospinal venous insufficiency (CCSVI). We investigated the sensitivity and specificity of 2 invasive vs. 2 noninvasive imaging techniques for the detection of extracranial venous anomalies in the internal jugular veins (IJVs) and azygos vein/vertebral veins (VVs) in patients with multiple sclerosis (MS). Methods The data for this multimodal imaging comparison pilot study was collected in phase 2 of the “Prospective Randomized Endovascular therapy in Multiple Sclerosis” (PREMiSe) study using standardized imaging techniques. Thirty MS subjects were screened initially with Doppler sonography (DS), out of which 10 did not fulfill noninvasive screening procedure requirements on DS that consisted of ≥2 venous hemodynamic extracranial criteria. Accordingly, 20 MS patients with relapsing MS were enrolled into the multimodal diagnostic imaging study. For magnetic resonance venography (MRV), IJVs abnormal findings were considered absent or pinpoint flow, whereas abnormal VVs flow was classified as absent. Abnormalities of the VVs were determined only using non-invasive testing. Catheter venography (CV) was considered abnormal when ≥50% lumen restriction was detected, while intravascular ultrasound (IVUS) was considered abnormal when ≥50% restriction of the lumen or intra-luminal defects or reduced pulsatility was found. Non-invasive and invasive imaging modality comparisons between left, right and total IJVs and between the VVs and azygos vein were performed. Because there is no reliable way of non-invasively assessing the azygos vein, the VVs abnormalities detected by the non-invasive testing were compared to the azygos abnormalities detected by the invasive testing. All image modalities were analyzed in a blinded manner by more than one viewer, upon which consensus was reached. The sensitivity and specificity were calculated using contingency tables denoting the presence or absence of vein-specific abnormality findings between all imaging modalities used individually as the benchmark. Results The sensitivity of CV + IVUS was 68.4% for the right and 90% for the left IJV and 85.7% for the azygos vein/VVs, compared to venous anomalies detected on DS. Compared to the venous anomalies detected on MRV, the sensitivity of CV + IVUS was 71.4% in right and 100% in left IJVs and 100% in the azygos vein/VVs; however, the specificity was 38.5%, 38.9% and 11.8%, respectively. The sensitivity between the two invasive imaging techniques, used as benchmarks, ranged from 72.7% for the right IJV to 90% for the azygos vein but the IVUS showed a higher rate of venous anomalies than the CV. There was excellent correspondence between identifying collateral veins on MRV and CV. Conclusions Noninvasive DS screening for the detection of venous anomalies indicative of CCSVI may be a reliable approach for identifying patients eligible for further multimodal invasive imaging testing of the IJVs. However, the noninvasive screening methods were inadequate to depict the total amount of azygos vein/VVs anomalies identified with invasive testing. This pilot study, with limited sample size, shows that both a non-invasive and invasive multimodal imaging diagnostic approach should be recommended to depict a range of extracranial venous anomalies indicative of CCSVI. However, lack of invasive testing on the study subjects whose results were negative on the DS screening and of healthy controls, limits further generalizibility of our findings. In addition, the findings from the 2 invasive techniques confirmed the existence of severe extracranial venous anomalies that significantly impaired normal blood outflow from the brain in this group of MS patients. PMID:24139135

Imaging Polarimetry in Central Serous Chorioretinopathy

PubMed Central

MIURA, MASAHIRO; ELSNER, ANN E.; WEBER, ANKE; CHENEY, MICHAEL C.; OSAKO, MASAHIRO; USUI, MASAHIKO; IWASAKI, TAKUYA

2006-01-01

PURPOSE To evaluate a noninvasive technique to detect the leakage point of central serous chorioretinopathy (CSR), using a polarimetry method. DESIGN Prospective cohort study. METHODS SETTING Institutional practice. PATIENTS We examined 30 eyes of 30 patients with CSR. MAIN OUTCOME MEASURES Polarimetry images were recorded using the GDx-N (Laser Diagnostic Technologies). We computed four images that differed in their polarization content: a depolarized light image, an average reflectance image, a parallel polarized light image, and a birefringence image. Each polarimetry image was compared with abnormalities seen on fluorescein angiography. RESULTS In all eyes, leakage area could be clearly visualized as a bright area in the depolarized light images. Michelson contrasts for the leakage areas were 0.58 ± 0.28 in the depolarized light images, 0.17 ± 0.11 in the average reflectance images, 0.09 ± 0.09 in the parallel polarized light images, and 0.11 ± 0.21 in the birefringence images from the same raw data. Michelson contrasts in depolarized light images were significantly higher than for the other three images (P < .0001, for all tests, paired t test). The fluid accumulated in the retina was well-visualized in the average and parallel polarized light images. CONCLUSIONS Polarization-sensitive imaging could readily localize the leakage point and area of fluid in CSR. This may assist with the rapid, noninvasive assessment of CSR. PMID:16376644

State-of-the-art magnetic resonance imaging of pancreatic cancer.

PubMed

Schima, Wolfgang; Ba-Ssalamah, Ahmed; Goetzinger, Peter; Scharitzer, Martina; Koelblinger, Claus

2007-12-01

Technical advances of magnetic resonance imaging (MRI), including ultrahigh-field magnetic resonance at 3.0 T, parallel imaging techniques, and multichannel receive coils of the abdomen, have promoted MRI of the pancreas. For adenocarcinoma, which is the most common malignant pancreatic tumor, helical CT has been most often used for detection and staging, but it has limitations in the detection of small cancers 2 cm in diameter or less (sensitivity, 63%). Moreover, it is not very accurate in determining nonresectability, because small liver metastases, peritoneal carcinomatosis, and subtle signs of vascular infiltration may be missed. At ultrahigh field at 3.0 T, gadolinium-enhanced MRI using volume-interpolated 3-dimensional gradient-recalled echo pulse sequences with near-isotropic voxels are very useful for detection of subtle abnormalities. Mangafodipir-enhanced MRI reveals a very high tumor-pancreas contrast, which helps to diagnose small cancers. Contrast-enhanced MRI is a problem-solving tool in case of equivocal CT: it helps to differentiate between cancer and focal pancreatitis. Neuroendocrine carcinoma may present with a spectrum of appearances at MRI, but the primary tumor and liver metastases are hypervascular in approximately 70%. In this article, pancreas imaging protocols for 1.5 and 3.0 T are explained. We present the imaging features of pancreatic cancer and the important questions in staging, which should be addressed by the radiologist.

Barium swallow study in routine clinical practice: a prospective study in patients with chronic cough*,**

PubMed Central

Nin, Carlos Shuler; Marchiori, Edson; Irion, Klaus Loureiro; Paludo, Artur de Oliveira; Alves, Giordano Rafael Tronco; Hochhegger, Daniela Reis; Hochhegger, Bruno

2013-01-01

OBJECTIVE: To assess the routine use of barium swallow study in patients with chronic cough. METHODS: Between October of 2011 and March of 2012, 95 consecutive patients submitted to chest X-ray due to chronic cough (duration > 8 weeks) were included in the study. For study purposes, additional images were obtained immediately after the oral administration of 5 mL of a 5% barium sulfate suspension. Two radiologists systematically evaluated all of the images in order to identify any pathological changes. Fisher's exact test and the chi-square test for categorical data were used in the comparisons. RESULTS: The images taken immediately after barium swallow revealed significant pathological conditions that were potentially related to chronic cough in 12 (12.6%) of the 95 patients. These conditions, which included diaphragmatic hiatal hernia, esophageal neoplasm, achalasia, esophageal diverticulum, and abnormal esophageal dilatation, were not detected on the images taken without contrast. After appropriate treatment, the symptoms disappeared in 11 (91.6%) of the patients, whereas the treatment was ineffective in 1 (8.4%). We observed no complications related to barium swallow, such as contrast aspiration. CONCLUSIONS: Barium swallow improved the detection of significant radiographic findings related to chronic cough in 11.5% of patients. These initial findings suggest that the routine use of barium swallow can significantly increase the sensitivity of chest X-rays in the detection of chronic cough-related etiologies. PMID:24473762

Comparing multifocal VEP and standard automated perimetry in high-risk ocular hypertension and early glaucoma.

PubMed

Fortune, Brad; Demirel, Shaban; Zhang, Xian; Hood, Donald C; Patterson, Emily; Jamil, Annisa; Mansberger, Steven L; Cioffi, George A; Johnson, Chris A

2007-03-01

To compare the diagnostic performance of multifocal visual evoked potential (mfVEP) and standard automated perimetry (SAP), in eyes with high-risk ocular hypertension or early glaucoma. Both eyes of 185 individuals with high-risk ocular hypertension or early glaucoma were evaluated. Subjects ranged in age from 37 to 87 (mean +/- SD: 61 +/- 11 years). Pattern-reversal mfVEPs were obtained by using VERIS (Electro-Diagnostic Imaging, San Mateo, CA) with a four-electrode array and were analyzed with custom software. SAP visual fields (SITA-standard; Carl Zeiss Meditec, Inc., Dublin, CA) were obtained within 22.3 +/- 27.0 days of the mfVEP. Stereo disc photographs and Heidelberg Retina Tomograph (HRT) images were obtained during one visit, which was within 24.8 +/- 50.4 days of the mfVEP and 33.1 +/- 62.9 days of the SAP visual field. Abnormalities on the mfVEP were defined by using a variety of cluster criteria: SAP with pattern standard deviation (PSD) P

Abnormal synergistic effects between Lewis acid-base interaction and halogen bond in F3B···NCX···NCM

NASA Astrophysics Data System (ADS)

Tang, Qingjie; Li, Qingzhong

2015-12-01

An abnormal synergistic effect was found between the Lewis acid-base interaction and halogen bond in triads F3B···NCX···NCM (X and M are halogen atoms), where the strong Lewis acid-base interaction between F3B and NCX has a larger enhancement than the weak halogen bond between NCX and NCM. This is in contrast with the traditional cooperative effect. It is interesting that the alkali-metal substituent as well as the heavier halogen atom play a more remarkable role in the enhancement of the interaction F3B···NCX than that of NCX···NCM, particularly, the alkali-metal substituent makes the abnormal synergistic effect be the traditional cooperative one.

A Sensitive Dynamic and Active Pixel Vision Sensor for Color or Neural Imaging Applications.

PubMed

Moeys, Diederik Paul; Corradi, Federico; Li, Chenghan; Bamford, Simeon A; Longinotti, Luca; Voigt, Fabian F; Berry, Stewart; Taverni, Gemma; Helmchen, Fritjof; Delbruck, Tobi

2018-02-01

Applications requiring detection of small visual contrast require high sensitivity. Event cameras can provide higher dynamic range (DR) and reduce data rate and latency, but most existing event cameras have limited sensitivity. This paper presents the results of a 180-nm Towerjazz CIS process vision sensor called SDAVIS192. It outputs temporal contrast dynamic vision sensor (DVS) events and conventional active pixel sensor frames. The SDAVIS192 improves on previous DAVIS sensors with higher sensitivity for temporal contrast. The temporal contrast thresholds can be set down to 1% for negative changes in logarithmic intensity (OFF events) and down to 3.5% for positive changes (ON events). The achievement is possible through the adoption of an in-pixel preamplification stage. This preamplifier reduces the effective intrascene DR of the sensor (70 dB for OFF and 50 dB for ON), but an automated operating region control allows up to at least 110-dB DR for OFF events. A second contribution of this paper is the development of characterization methodology for measuring DVS event detection thresholds by incorporating a measure of signal-to-noise ratio (SNR). At average SNR of 30 dB, the DVS temporal contrast threshold fixed pattern noise is measured to be 0.3%-0.8% temporal contrast. Results comparing monochrome and RGBW color filter array DVS events are presented. The higher sensitivity of SDAVIS192 make this sensor potentially useful for calcium imaging, as shown in a recording from cultured neurons expressing calcium sensitive green fluorescent protein GCaMP6f.

Biocompatibility of hyaluronic acid hydrogels prepared by porous hyaluronic acid microbeads

NASA Astrophysics Data System (ADS)

Kim, Jin-Tae; Lee, Deuk Yong; Kim, Tae-Hyung; Song, Yo-Seung; Cho, Nam-Ihn

2014-05-01

Hyaluronic acid hydrogels (HAHs) were synthesized by immersing HA microbeads crosslinked with divinyl sulfone in a phosphate buffered saline solution to evaluate the biocompatibility of the gels by means of cytotoxicity, genotoxicity ( in vitro chromosome aberration test, reverse mutation assay, and in vivo micronucleus test), skin sensitization, and intradermal reactivity. The HAHs induced no cytotoxicity or genotoxicity. In guinea pigs treated with grafts and prostheses, no animals died and there were no abnormal clinical signs. The sensitization scores were zero in all guinea pigs after 24 h and 48 h challenge, suggesting that the HAHs had no contact allergic sensitization in the guinea pig maximization test. No abnormal signs were found in New Zealand White rabbits during the 72 h observation period after the injection. There was no difference between the HAHs and negative control mean scores because skin reaction such as erythema or oedema was not observed after injection. Experimental results suggest that the HAHs would be suitable for soft tissue augmentation due to the absence of cytotoxicity, genotoxicity, skin sensitization, and intradermal reactivity.

Mechanisms of Normal and Abnormal Endometrial Bleeding

PubMed Central

Lockwood, Charles J.

2011-01-01

Expression of tissue factor (TF), the primary initiator of coagulation, is enhanced in decidualized human endometrial stromal cells (HESC) during the progesterone-dominated luteal phase. Progesterone also augments a second HESC hemostatic factor, plasminogen activator inhibitor-1 (PAI-1). In contrast, progestins inhibit HESC matrix metalloproteinase (MMP)-1, 3 and 9 expression to stabilize endometrial stromal and vascular extracellular matrix. Through these mechanisms decidualized endometrium is rendered both hemostatic and resistant to excess trophoblast invasion in the mid-luteal phase and throughout gestation to prevent hemorrhage and accreta. In non-fertile cycles, progesterone withdrawal results in decreased HESC TF and PAI-expression and increased MMP activity and inflammatory cytokine production promoting the controlled hemorrhage of menstruation and related tissue sloughing. In contrast to these well ordered biochemical processes, unpredictable endometrial bleeding associated with anovulation reflects absence of progestational effects on TF, PAI-1 and MMP activity as well as unrestrained angiogenesis rendering the endometrium non-hemostatic, proteolytic and highly vascular. Abnormal bleeding associated with long-term progestin-only contraceptives results not from impaired hemostasis but from unrestrained angiogenesis leading to large fragile endometrial vessels. This abnormal angiogenesis reflects progestational inhibition of endometrial blood flow promoting local hypoxia and generation of reactive oxygen species that increase production of angiogenic factors such as vascular endothelial growth factor (VEGF) in HESCs and Angiopoietin-2 (Ang-2) in endometrial endothelial cells while decreasing HESC expression of angiostatic, Ang-1. The resulting vessel fragility promotes bleeding. Aberrant angiogenesis also underlies abnormal bleeding associated with myomas and endometrial polyps however there are gaps in our understanding of this pathology. PMID:21499503

Patterns of pulmonary maturation in normal and abnormal pregnancy.

PubMed

Goldkrand, J W; Slattery, D S

1979-03-01

Fetal pulmonary maturation may be a variable event depending on various feto-maternal environmental and biochemical influences. The patterns of maturation were studied in 211 amniotic fluid samples from 123 patients (normal 55; diabetes 23; Rh sensitization 19; preeclampsia 26). The phenomenon of globule formation from the amniotic fluid lipid extract and is relation to pulmonary maturity was utilized for this analysis. Validation of this technique is presented. A normal curve was constructed from 22 to 42 weeks; gestation and compared to the abnormal pregnancies. Patients with class A, B, and C diabetes and Rh-sensitized pregnancies had delayed pulmonary maturation. Patients with class D diabetes and preclampsia paralleled the normal course of maturation. A discussion of these results and their possible cause is presented.

A temporal examination of co-activated emotion valence networks in schizophrenia and schizotypy

PubMed Central

Cohen, Alex S.; Callaway, Dallas A.; Mitchell, Kyle R.; Larsen, Jeff T.; Strauss, Gregory P.

2016-01-01

Emotional abnormalities are prominent across the schizophrenia spectrum. To better define these abnormalities, we examined state emotional functions across opposing ends of the spectrum, notably in chronic outpatients with schizophrenia (Study 1) and college students with psychometrically defined schizotypy (Study 2). In line with existing studies, we predicted that individuals with schizophrenia would show unusually co-activated positive and negative emotions while college students with schizotypy would show abnormally low positive and abnormally high negative emotions. Drawing from the affective science literature, we employed continuous emotion ratings in response to a dynamic and evocatively “bittersweet” stimulus. Participants included 27 individuals with schizophrenia, 39 individuals with psychometrically defined schizotypy and 26 community and 35 college control participants. Participants continuously rated their state happiness and sadness throughout a six-minute clip from a tragicomic film (i.e., Life is Beautiful). In contrast to expectations as well as the extant literature, there were no state emotional abnormalities noted from either schizophrenia-spectrum group. Of particular note, neither individuals with schizophrenia nor individuals with schizotypy were abnormal in their experience of state negative, positive or coactivated emotions. Conversely, abnormalities in trait emotion were observed in both groups relative to their respective control groups. These results help confirm that the schizophrenia-spectrum is not characterized by deficits in state emotional experience and suggest that sadness is not abnormally co-activated with pleasant emotions. These results are critical for clarifying the “chronometry” of emotional dysfunctions across the schizophrenia-spectrum. PMID:26711714

Sensitivity, Specificity, and Predictive Values of Pediatric Metabolic Syndrome Components in Relation to Adult Metabolic Syndrome: The Princeton LRC Follow-up Study

PubMed Central

Huang, Terry T-K; Nansel, Tonja R.; Belsheim, Allen R.; Morrison, John A.

2008-01-01

Objective To estimate the sensitivity, specificity, and predictive values of pediatric metabolic syndrome (MetS) components (obesity, fasting glucose, triglycerides, high-density lipoprotein, and blood pressure) at various cutoffs in relation to adult MetS. Study design Data from the NHLBI Lipid Research Clinics (LRC) Princeton Prevalence Study (1973–76) and the Princeton Follow-up Study (PFS, 2000-4) were used to calculate sensitivity, specificity, and positive and negative predictive values for each component at a given cutoff, as well as for aggregates of components. Results Individual pediatric components alone showed low to moderate sensitivity, high specificity, and moderate predictive values in relation to adult MetS. When all five pediatric MetS components were considered, the presence of at least one abnormality had higher sensitivity for adult MetS than individual components alone. When multiple abnormalities were mandatory for MetS, positive predictive value was high and sensitivity was low. Childhood body mass alone showed neither high sensitivity nor high positive predictive value for adult MetS. Conclusions Considering multiple metabolic variables in childhood can improve the predictive utility for adult MetS, compared to each component or body mass alone. MetS variables may be useful for identifying some at risk children for prevention interventions. PMID:18206687

Parametric Imaging Of Digital Subtraction Angiography Studies For Renal Transplant Evaluation

NASA Astrophysics Data System (ADS)

Gallagher, Joe H.; Meaney, Thomas F.; Flechner, Stuart M.; Novick, Andrew C.; Buonocore, Edward

1981-11-01

A noninvasive method for diagnosing acute tubular necrosis and rejection would be an important tool for the management of renal transplant patients. From a sequence of digital subtraction angiographic images acquired after an intravenous injection of radiographic contrast material, the parametric images of the maximum contrast, the time when the maximum contrast is reached, and two times the time at which one half of the maximum contrast is reached are computed. The parametric images of the time when the maximum is reached clearly distinguish normal from abnormal renal function. However, it is the parametric image of two times the time when one half of the maximum is reached which provides some assistance in differentiating acute tubular necrosis from rejection.

Chromatic and achromatic visual fields in relation to choroidal thickness in patients with high myopia: A pilot study.

PubMed

García-Domene, M C; Luque, M J; Díez-Ajenjo, M A; Desco-Esteban, M C; Artigas, J M

2018-02-01

To analyse the relationship between the choroidal thickness and the visual perception of patients with high myopia but without retinal damage. All patients underwent ophthalmic evaluation including a slit lamp examination and dilated ophthalmoscopy, subjective refraction, best corrected visual acuity, axial length, optical coherence tomography, contrast sensitivity function and sensitivity of the visual pathways. We included eleven eyes of subjects with high myopia. There are statistical correlations between choroidal thickness and almost all the contrast sensitivity values. The sensitivity of magnocellular and koniocellular pathways is the most affected, and the homogeneity of the sensibility of the magnocellular pathway depends on the choroidal thickness; when the thickness decreases, the sensitivity impairment extends from the center to the periphery of the visual field. Patients with high myopia without any fundus changes have visual impairments. We have found that choroidal thickness correlates with perceptual parameters such as contrast sensitivity or mean defect and pattern standard deviation of the visual fields of some visual pathways. Our study shows that the magnocellular and koniocellular pathways are the most affected, so that these patients have impairment in motion perception and blue-yellow contrast perception. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Normal Visual Acuity and Electrophysiological Contrast Gain in Adults with High-Functioning Autism Spectrum Disorder.

PubMed

Tebartz van Elst, Ludger; Bach, Michael; Blessing, Julia; Riedel, Andreas; Bubl, Emanuel

2015-01-01

A common neurodevelopmental disorder, autism spectrum disorder (ASD), is defined by specific patterns in social perception, social competence, communication, highly circumscribed interests, and a strong subjective need for behavioral routines. Furthermore, distinctive features of visual perception, such as markedly reduced eye contact and a tendency to focus more on small, visual items than on holistic perception, have long been recognized as typical ASD characteristics. Recent debate in the scientific community discusses whether the physiology of low-level visual perception might explain such higher visual abnormalities. While reports of this enhanced, "eagle-like" visual acuity contained methodological errors and could not be substantiated, several authors have reported alterations in even earlier stages of visual processing, such as contrast perception and motion perception at the occipital cortex level. Therefore, in this project, we have investigated the electrophysiology of very early visual processing by analyzing the pattern electroretinogram-based contrast gain, the background noise amplitude, and the psychophysical visual acuities of participants with high-functioning ASD and controls with equal education. Based on earlier findings, we hypothesized that alterations in early vision would be present in ASD participants. This study included 33 individuals with ASD (11 female) and 33 control individuals (12 female). The groups were matched in terms of age, gender, and education level. We found no evidence of altered electrophysiological retinal contrast processing or psychophysical measured visual acuities. There appears to be no evidence for abnormalities in retinal visual processing in ASD patients, at least with respect to contrast detection.

Set-membership fault detection under noisy environment with application to the detection of abnormal aircraft control surface positions

NASA Astrophysics Data System (ADS)

El Houda Thabet, Rihab; Combastel, Christophe; Raïssi, Tarek; Zolghadri, Ali

2015-09-01

The paper develops a set membership detection methodology which is applied to the detection of abnormal positions of aircraft control surfaces. Robust and early detection of such abnormal positions is an important issue for early system reconfiguration and overall optimisation of aircraft design. In order to improve fault sensitivity while ensuring a high level of robustness, the method combines a data-driven characterisation of noise and a model-driven approach based on interval prediction. The efficiency of the proposed methodology is illustrated through simulation results obtained based on data recorded in several flight scenarios of a highly representative aircraft benchmark.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brasch, R.C.; Wesbey, G.E.; Gooding, C.A.

Tissue deposits of hemosiderin, a paramagnetic iron-protein complex, resulted in marked abnormalities of magnetic resonance (MR) spin-echo signal intensity within the viscera of three children with transfusional hemosiderosis and thalassemia major. In all patients the liver and bone marrow demonstrated abnormally low spin-echo intensities and the kidneys and muscles had abnormally high intensities. These observations correlate with in vitro MR observation of ferric (Fe/sup +3/) solutions, in which concentrations of ferric salts greater than 20 mmol yielded higher intensities than did water alone. MR imaging is sensitive to the tissue deposition of hemosiderin, and MR intensity appears to provide amore » rough measure of the amount of iron deposited.« less

Visible Contrast Energy Metrics for Detection and Discrimination

NASA Technical Reports Server (NTRS)

Ahumada, Albert; Watson, Andrew

2013-01-01

Contrast energy was proposed by Watson, Robson, & Barlow as a useful metric for representing luminance contrast target stimuli because it represents the detectability of the stimulus in photon noise for an ideal observer. Like the eye, the ear is a complex transducer system, but relatively simple sound level meters are used to characterize sounds. These meters provide a range of frequency sensitivity functions and integration times depending on the intended use. We propose here the use of a range of contrast energy measures with different spatial frequency contrast sensitivity weightings, eccentricity sensitivity weightings, and temporal integration times. When detection threshold are plotting using such measures, the results show what the eye sees best when these variables are taken into account in a standard way. The suggested weighting functions revise the Standard Spatial Observer for luminance contrast detection and extend it into the near periphery. Under the assumption that the detection is limited only by internal noise, discrimination performance can be predicted by metrics based on the visible energy of the difference images

Lexical stress contrast marking in fluent and non-fluent aphasia in Spanish: The relationship between acoustic cues and compensatory strategies.

PubMed

Baqué, Lorraine

2017-01-01

This study sought to investigate stress production in Spanish by patients with Broca's (BA) and conduction aphasia (CA) as compared to controls. Our objectives were to assess whether: a) there were many abnormal acoustic correlates of stress as produced by patients, b) these abnormalities had a phonetic component and c) ability for articulatory compensation for stress marking was preserved. The results showed abnormal acoustic values in both BA and CA's productions, affecting not only duration but also F0 and intensity cues, and an interaction effect of stress pattern and duration on intensity cubes in BA, but not in CA or controls. The results are interpreted as deriving from two different underlying phenomena: in BA, a compensatory use of intensity as a stress cue in order to avoid 'equal stress'; in CA, related to either a 'subtle phonetic deficit' involving abnormal stress acoustic cue-processing or to 'clear-speech' effects.

Solitary tuberculous brain lesions: 24 new cases and a review of the literature.

PubMed

Psimaras, D; Bonnet, C; Heinzmann, A; Cárdenas, G; Hernández José Luis, S; Tungaria, A; Behari, S; Lacrois, D; Mokhtari, K; Karantoni, E; Sokrab Tag, E; Idris Mohamed, N; Sönmez, G; Caumes, E; Roze, E

2014-01-01

A solitary tuberculous brain lesion (STBL) can be difficult to distinguish from a glioma, metastasis or other infectious disease, especially from a pyogenic brain abscess. We analyzed the clinical characteristics, diagnostic procedures and outcomes of 24 patients with STBL diagnosed in three centers from France, India and Mexico. We also reviewed 92 STBL cases previously reported in the literature. General symptoms were found in 54% of our patients, including enlarged lymph nodes in 20%. Cerebrospinal fluid was typically abnormal, with lymphocytic pleocytosis and a high protein level. The lung CT scan was abnormal in 56% of patients, showing lymphadenopathy or pachipleuritis. Brain MRI or CT was always abnormal, showing contrast-enhanced lesions. Typically, MRI abnormalities were hypointense on T1-weighted sequences, while T2-weighted sequences showed both a peripheral hypersignal and a central hyposignal. The diagnosis was documented microbiologically or supported histologically in 71% of cases. Clinical outcome was good in 83% of cases. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

A quantitative survey of gravity receptor function in mutant mouse strains.

PubMed

Jones, Sherri M; Johnson, Kenneth R; Yu, Heping; Erway, Lawrence C; Alagramam, Kumar N; Pollak, Natasha; Jones, Timothy A

2005-12-01

The purpose of this research was to identify vestibular deficits in mice using linear vestibular evoked potentials (VsEPs). VsEP thresholds, peak latencies, and peak amplitudes from 24 strains with known genetic mutations and 6 inbred background strains were analyzed and descriptive statistics generated for each strain. Response parameters from mutant homozygotes were compared with heterozygote and/or background controls and all strain averages were contrasted to normative ranges. Homozygotes of the following recessive mutations had absent VsEPs at the ages tested: Espn(je), Atp2b2dfw-2J, Spnb4qv-lnd2J, Spnb4qv-3J, Myo7ash1, Tmie(sr), Myo6sv, jc, Pcdh15av-J, Pcdh15av-2J, Pcdh15av-3J, Cdh23v-2J, Sans(js), hr, Kcne1pkr and Pou3f4del. These results suggest profound gravity receptor deficits for these homozygotes, which is consistent with the structural deficits that have been documented for many of these strains. Homozygotes of Catna2cdf, Grid2ho4J, Wnt1sw, qk, and Mbpshi strains and heterozygotes of Grid2lc had measurable VsEPs but one or more response parameters differed from the respective control group (heterozygote or background strain) or were outside normal ranges. For example, qk and Mbpshi homozygotes showed significantly prolonged latencies consistent with the abnormal myelin that has been described for these strains. Prolonged latencies may suggest deficits in neural conduction; elevated thresholds suggest reduced sensitivity, and reduced amplitudes may be suggestive for reduced neural synchrony. One mutation, Otx1jv, had all VsEP response parameters within normal limits--an expected finding because the abnormality in Otxljv is presumably restricted to the lateral semicircular canal. Interestingly, some heterozygote groups also showed abnormalities in one or more VsEP response parameters, suggesting that vestibular dysfunction, although less severe, may be present in some heterozygous animals.

Diagnostic accuracy of 3D-transvaginal ultrasound in detecting uterine cavity abnormalities in infertile patients as compared with hysteroscopy.

PubMed

Apirakviriya, Chayanis; Rungruxsirivorn, Tassawan; Phupong, Vorapong; Wisawasukmongchol, Wirach

2016-05-01

To assess diagnostic accuracy of 3D transvaginal ultrasound (3D-TVS) compared with hysteroscopy in detecting uterine cavity abnormalities in infertile women. This prospective observational cross-sectional study was conducted during the July 2013 to December 2013 study period. Sixty-nine women with infertility were enrolled. In the mid to late follicular phase of each subject's menstrual cycle, 3D transvaginal ultrasound and hysteroscopy were performed on the same day in each patient. Hysteroscopy is widely considered to be the gold standard method for investigation of the uterine cavity. Uterine cavity characteristics and abnormalities were recorded. Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios were evaluated. Hysteroscopy was successfully performed in all subjects. Hysteroscopy diagnosed pathological findings in 22 of 69 cases (31.8%). There were 18 endometrial polyps, 3 submucous myomas, and 1 septate uterus. Three-dimensional transvaginal ultrasound in comparison with hysteroscopy had 84.1% diagnostic accuracy, 68.2% sensitivity, 91.5% specificity, 79% positive predictive value, and 86% negative predictive value. The positive and negative likelihood ratios were 8.01 and 0.3, respectively. 3D-TVS successfully detected every case of submucous myoma and uterine anomaly. For detection of endometrial polyps, 3D-TVS had 61.1% sensitivity, 91.5% specificity, and 83.1% diagnostic accuracy. 3D-TVS demonstrated 84.1% diagnostic accuracy for detecting uterine cavity abnormalities in infertile women. A significant percentage of infertile patients had evidence of uterine cavity pathology. Hysteroscopy is, therefore, recommended for accurate detection and diagnosis of uterine cavity lesion. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

No Association between Cortical Gyrification or Intrinsic Curvature and Attention-deficit/Hyperactivity Disorder in Adolescents and Young Adults.

PubMed

Forde, Natalie J; Ronan, Lisa; Zwiers, Marcel P; Alexander-Bloch, Aaron F; Faraone, Stephen V; Oosterlaan, Jaap; Heslenfeld, Dirk J; Hartman, Catharina A; Buitelaar, Jan K; Hoekstra, Pieter J

2017-01-01

Magnetic resonance imaging (MRI) studies have highlighted subcortical, cortical, and structural connectivity abnormalities associated with attention-deficit/hyperactivity disorder (ADHD). Gyrification investigations of the cortex have been inconsistent and largely negative, potentially due to a lack of sensitivity of the previously used morphological parameters. The innovative approach of applying intrinsic curvature analysis, which is predictive of gyrification pattern, to the cortical surface applied herein allowed us greater sensitivity to determine whether the structural connectivity abnormalities thus far identified at a centimeter scale also occur at a millimeter scale within the cortical surface. This could help identify neurodevelopmental processes that contribute to ADHD. Structural MRI datasets from the NeuroIMAGE project were used [ n = 306 ADHD, n = 164 controls, and n = 148 healthy siblings of individuals with ADHD (age in years, mean(sd); 17.2 (3.4), 16.8 (3.2), and 17.7 (3.8), respectively)]. Reconstructions of the cortical surfaces were computed with FreeSurfer. Intrinsic curvature (taken as a marker of millimeter-scale surface connectivity) and local gyrification index were calculated for each point on the surface (vertex) with Caret and FreeSurfer, respectively. Intrinsic curvature skew and mean local gyrification index were extracted per region; frontal, parietal, temporal, occipital, cingulate, and insula. A generalized additive model was used to compare the trajectory of these measures between groups over age, with sex, scanner site, total surface area of hemisphere, and familiality accounted for. After correcting for sex, scanner site, and total surface area no group differences were found in the developmental trajectory of intrinsic curvature or local gyrification index. Despite the increased sensitivity of intrinsic curvature, compared to gyrification measures, to subtle morphological abnormalities of the cortical surface we found no milimeter-scale connectivity abnormalities associated with ADHD.

Cocaine addiction is associated with abnormal prefrontal function, increased striatal connectivity and sensitivity to monetary incentives, and decreased connectivity outside the human reward circuit.

PubMed

Vaquero, Lucía; Cámara, Estela; Sampedro, Frederic; Pérez de Los Cobos, José; Batlle, Francesca; Fabregas, Josep Maria; Sales, Joan Artur; Cervantes, Mercè; Ferrer, Xavier; Lazcano, Gerardo; Rodríguez-Fornells, Antoni; Riba, Jordi

2017-05-01

Cocaine addiction has been associated with increased sensitivity of the human reward circuit to drug-related stimuli. However, the capacity of non-drug incentives to engage this network is poorly understood. Here, we characterized the functional sensitivity to monetary incentives and the structural integrity of the human reward circuit in abstinent cocaine-dependent (CD) patients and their matched controls. We assessed the BOLD response to monetary gains and losses in 30 CD patients and 30 healthy controls performing a lottery task in a magnetic resonance imaging scanner. We measured brain gray matter volume (GMV) using voxel-based morphometry and white matter microstructure using voxel-based fractional anisotropy (FA). Functional data showed that, after monetary incentives, CD patients exhibited higher activation in the ventral striatum than controls. Furthermore, we observed an inverted BOLD response pattern in the prefrontal cortex, with activity being highest after unexpected high gains and lowest after losses. Patients showed increased GMV in the caudate and the orbitofrontal cortex, increased white matter FA in the orbito-striatal pathway but decreased FA in antero-posterior association bundles. Abnormal activation in the prefrontal cortex correlated with GMV and FA increases in the orbitofrontal cortex. While functional abnormalities in the ventral striatum were inversely correlated with abstinence duration, structural alterations were not. In conclusion, results suggest abnormal incentive processing in CD patients with high salience for rewards and punishments in subcortical structures but diminished prefrontal control after adverse outcomes. They further suggest that hypertrophy and hyper-connectivity within the reward circuit, to the expense of connectivity outside this network, characterize cocaine addiction. © 2016 Society for the Study of Addiction.

Lung clearance index is a repeatable and sensitive indicator of radiological changes in bronchiectasis.

PubMed

Rowan, Stephen A; Bradley, Judy M; Bradbury, Ian; Lawson, John; Lynch, Tom; Gustafsson, Per; Horsley, Alex; O'Neill, Katherine; Ennis, Madeleine; Elborn, J Stuart

2014-03-01

In bronchiectasis there is a need for improved markers of lung function to determine disease severity and response to therapy. To assess whether the lung clearance index is a repeatable and more sensitive indicator of computed tomography (CT) scan abnormalities than spirometry in bronchiectasis. Thirty patients with stable bronchiectasis were recruited and lung clearance index, spirometry, and health-related quality of life measures were assessed on two occasions, 2 weeks apart when stable (study 1). A separate group of 60 patients with stable bronchiectasis was studied on a single visit with the same measurements and a CT scan (study 2). In study 1, the intervisit intraclass correlation coefficient for the lung clearance index was 0.94 (95% confidence interval, 0.89 to 0.97; P < 0.001). In study 2, the mean age was 62 (10) years, FEV1 76.5% predicted (18.9), lung clearance index 9.1 (2.0), and total CT score 14.1 (10.2)%. The lung clearance index was abnormal in 53 of 60 patients (88%) and FEV1 was abnormal in 37 of 60 patients (62%). FEV1 negatively correlated with the lung clearance index (r = -0.51, P < 0.0001). Across CT scores, there was a relationship with the lung clearance index, with little evidence of an effect of FEV1. There were no significant associations between the lung clearance index or FEV1 and health-related quality of life. The lung clearance index is repeatable and a more sensitive measure than FEV1 in the detection of abnormalities demonstrated on CT scan. The lung clearance index has the potential to be a useful clinical and research tool in patients with bronchiectasis.

Is Suppression Just Normal Dichoptic Masking? Suprathreshold Considerations.

PubMed

Reynaud, Alexandre; Hess, Robert F

2016-10-01

Amblyopic patients have a deficit in visual acuity and contrast sensitivity in their amblyopic eye as well as suppression of the amblyopic eye input under binocular viewing conditions. In this study we wanted to assess the origin of the amblyopic suppression by studying the contrast perception of the amblyopic eye at suprathreshold levels under binocular and monocular viewing. Using a suprathreshold contrast matching task in which the reference and target stimuli were presented to different eyes either simultaneously or successively, we measured interocular contrast matching in 10 controls and 11 amblyopes (mean age 35 ± 15; 5 strabismics; 3 anisometropes; 3 mixed). This was then used as an index of the binocular balance across spatial frequency and compared against the contrast sensitivity ratio measured with the same stimuli. We observed that binocular matching becomes more imbalanced at high spatial frequency for amblyopes, compared with controls; that this imbalance did not depend in either group on whether the stimuli were presented simultaneously or successively; and that for both modes of presentation the matching balance correlates well with the interocular contrast sensitivity ratio (mean correlation coefficient of the slopes R = 0.7125). The results from our amblyopes show comparable losses of contrast perception at and above threshold under these binocular viewing conditions across a wide spatial frequency range, much stronger than that observed for our controls. This occurs under conditions in which there should be no dichoptic masking. Furthermore, the matching contrast could be well predicted by the monocular contrast sensitivity. Altogether, this suggests that amblyopic suppression cannot be explained by normal dichoptic masking but rather an attenuation of the input.

Visual resolution and contrast sensitivity in two benthic sharks.

PubMed

Ryan, Laura A; Hart, Nathan S; Collin, Shaun P; Hemmi, Jan M

2016-12-15

Sharks have long been described as having 'poor' vision. They are cone monochromats and anatomical estimates suggest they have low spatial resolution. However, there are no direct behavioural measurements of spatial resolution or contrast sensitivity. This study estimates contrast sensitivity and spatial resolution of two species of benthic sharks, the Port Jackson shark, Heterodontus portusjacksoni, and the brown-banded bamboo shark, Chiloscyllium punctatum, by recording eye movements in response to optokinetic stimuli. Both species tracked moving low spatial frequency gratings with weak but consistent eye movements. Eye movements ceased at 0.38 cycles per degree, even for high contrasts, suggesting low spatial resolution. However, at lower spatial frequencies, eye movements were elicited by low contrast gratings, 1.3% and 2.9% contrast in H portusjacksoni and C. punctatum, respectively. Contrast sensitivity was higher than in other vertebrates with a similar spatial resolving power, which may reflect an adaptation to the relatively low contrast encountered in aquatic environments. Optokinetic gain was consistently low and neither species stabilised the gratings on their retina. To check whether restraining the animals affected their optokinetic responses, we also analysed eye movements in free-swimming C. punctatum We found no eye movements that could compensate for body rotations, suggesting that vision may pass through phases of stabilisation and blur during swimming. As C. punctatum is a sedentary benthic species, gaze stabilisation during swimming may not be essential. Our results suggest that vision in sharks is not 'poor' as previously suggested, but optimised for contrast detection rather than spatial resolution. © 2016. Published by The Company of Biologists Ltd.

Real-Time Palpation Imaging for Improved Detection and Discrimination of Breast Abnormalities

DTIC Science & Technology

2005-07-01

contrasts are also in the range of elastic contrasts in terms of shear storage moduli for 85 Hz shear waves in in vivo MR breast elastography (Sinkus et al... elastography ) may aid the differentiation of benign and malignant solid breast masses .(4-19) This research is based on the fact that benign and malignant...on 445 breast masses of which 42 were discarded based on our exclusion criteria leaving 403 (157 malignant-39.0%; 246 benign-61.0%) lesions as

Brightness discrimination and contrast sensitivity in chronic glaucoma--a clinical study.

PubMed

Teoh, S L; Allan, D; Dutton, G N; Foulds, W S

1990-04-01

The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma.

The effects of longitudinal chromatic aberration and a shift in the peak of the middle-wavelength sensitive cone fundamental on cone contrast

PubMed Central

Rucker, F. J.; Osorio, D.

2009-01-01

Longitudinal chromatic aberration is a well-known imperfection of visual optics, but the consequences in natural conditions, and for the evolution of receptor spectral sensitivities are less well understood. This paper examines how chromatic aberration affects image quality in the middle-wavelength sensitive (M-) cones, viewing broad-band spectra, over a range of spatial frequencies and focal planes. We also model the effects on M-cone contrast of moving the M-cone fundamental relative to the long- and middle-wavelength (L- and M-cone) fundamentals, while the eye is accommodated at different focal planes or at a focal plane that maximizes luminance contrast. When the focal plane shifts towards longer (650 nm) or shorter wavelengths (420 nm) the effects on M-cone contrast are large: longitudinal chromatic aberration causes total loss of M-cone contrast above 10 to 20 c/d. In comparison, the shift of the M-cone fundamental causes smaller effects on M-cone contrast. At 10 c/d a shift in the peak of the M-cone spectrum from 560 nm to 460 nm decreases M-cone contrast by 30%, while a 10 nm blue-shift causes only a minor loss of contrast. However, a noticeable loss of contrast may be seen if the eye is focused at focal planes other than that which maximizes luminance contrast. The presence of separate long- and middle-wavelength sensitive cones therefore has a small, but not insignificant cost to the retinal image via longitudinal chromatic aberration. This aberration may therefore be a factor limiting evolution of visual pigments and trichromatic color vision. PMID:18639571

Diagnostic accuracy of contrast-enhanced computed tomography and contrast-enhanced magnetic resonance imaging of small renal masses in real practice: sensitivity and specificity according to subjective radiologic interpretation.

PubMed

Kim, Jae Heon; Sun, Hwa Yeon; Hwang, Jiyoung; Hong, Seong Sook; Cho, Yong Jin; Doo, Seung Whan; Yang, Won Jae; Song, Yun Seob

2016-10-12

The aim of this study was to investigate the diagnostic accuracy of contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) of small renal masses in real practice. Contrast-enhanced CT and MRI were performed between February 2008 and February 2013 on 68 patients who had suspected small (≤4 cm) renal cell carcinoma (RCC) based on ultrasonographic measurements. CT and MRI radiographs were reviewed, and the findings of small renal masses were re-categorized into five dichotomized scales by the same two radiologists who had interpreted the original images. Receiver operating characteristics curve analysis was performed, and sensitivity and specificity were determined. Among the 68 patients, 60 (88.2 %) had RCC and eight had benign disease. The diagnostic accuracy rates of contrast-enhanced CT and MRI were 79.41 and 88.23 %, respectively. Diagnostic accuracy was greater when using contrast-enhanced MRI because too many masses (67.6 %) were characterized as "4 (probably solid cancer) or 5 (definitely solid cancer)." The sensitivity of contrast-enhanced CT and MRI for predicting RCC were 79.7 and 88.1 %, respectively. The specificities of contrast-enhanced CT and MRI for predicting RCC were 44.4 and 33.3 %, respectively. Fourteen diagnoses (20.5 %) were missed or inconsistent compared with the final pathological diagnoses. One appropriate nephroureterectomy and five unnecessary percutaneous biopsies were performed for RCC. Seven unnecessary partial nephrectomies were performed for benign disease. Although contrast-enhanced CT and MRI showed high sensitivity for detecting small renal masses, specificity remained low.

Unipedal Diagnostic Lymphangiography Followed by Sequential CT Examinations in Patients With Idiopathic Chyluria: A Retrospective Study.

PubMed

Dong, Jian; Xin, Jianfeng; Shen, Wenbin; Chen, Xiaobai; Wen, Tingguo; Zhang, Chunyan; Wang, Rengui

2018-04-01

The objective of our study was to investigate the clinical value of diagnostic lymphangiography followed by sequential CT examinations in patients with idiopathic chyluria. Thirty-six patients with idiopathic chyluria underwent unipedal diagnostic lymphangiography and then underwent sequential CT examinations. The examinations were reviewed separately by two radiologists. Abnormal distribution of contrast medium, lymphourinary leakages, and retrograde flow were noted, and the range and distribution of lymphatic vessel lesions were recorded. The stage of idiopathic chyluria based on CT findings and the stage based on clinical findings were compared. Therapeutic management and follow-up were recorded. Statistical analyses were performed. Compared with CT studies performed after lymphangiography, diagnostic lymphangiography showed a unique capability to depict lymphourinary leakages in three patients. Lymphourinary fistulas and abnormal dilated lymphatic vessels were found in and around kidney in all patients. CT depicted retrograde flow of lymph fluid in 47.2% of patients. The consistency in staging chyluria based on CT findings and clinical findings was fair (κ = 0.455). Twenty-nine patients underwent conservative therapy, and seven underwent surgery. Surgical therapy was superior to conservative management (no recurrence, 85.7% of patients who underwent surgery vs 62.1% of patients who underwent conservative therapy; p = 0.025). From assessing the drainage of contrast medium on unipedal diagnostic lymphangiography and the redistribution of contrast medium on sequential CT examinations, it is possible to detect the existence of lymphourinary fistulas, the precise location of lymphatic anomalies, the distribution of collateral lymphatic vessels, and hydrodynamic pressure abnormality in the lymph circulation in patients with idiopathic chyluria. CT staging of chyluria provides additional information that can be used to guide therapeutic management.

Retinal nerve fibre thickness measured with optical coherence tomography accurately detects confirmed glaucomatous damage.

PubMed

Hood, D C; Harizman, N; Kanadani, F N; Grippo, T M; Baharestani, S; Greenstein, V C; Liebmann, J M; Ritch, R

2007-07-01

To assess the accuracy of optical coherence tomography (OCT) in detecting damage to a hemifield, patients with hemifield defects confirmed on both static automated perimetry (SAP) and multifocal visual evoked potentials (mfVEP) were studied. Eyes of 40 patients with concomitant SAP and mfVEP glaucomatous loss and 25 controls underwent OCT retinal nerve fibre layer (RNFL), mfVEP and 24-2 SAP tests. For the mfVEP and 24-2 SAP, a hemifield was defined as abnormal based upon cluster criteria. On OCT, a hemifield was considered abnormal if one of the five clock hour sectors (3 and 9 o'clock excluded) was at <1% (red) or two were at <5% (yellow). Seventy seven (43%) of the hemifields were abnormal on both mfVEP and SAP tests. The OCT was abnormal for 73 (95%) of these. Only 1 (1%) of the 100 hemifields of the controls was abnormal on OCT. Sensitivity/specificity (one eye per person) was 95/98%. The OCT RNFL test accurately detects abnormal hemifields confirmed on both subjective and objective functional tests. Identifying abnormal hemifields with a criterion of 1 red (1%) or 2 yellow (5%) clock hours may prove useful in clinical practice.

Clinical accuracy of abnormal cell-free fetal DNA results for the sex chromosomes.

PubMed

Scibetta, Emily W; Gaw, Stephanie L; Rao, Rashmi R; Silverman, Neil S; Han, Christina S; Platt, Lawrence D

2017-12-01

To investigate factors associated with abnormal cell-free DNA (cfDNA) results for sex chromosomes (SCs). This is a retrospective cohort study of abnormal cfDNA results for SC at a referral practice from March 2013 to July 2015. Cell-free DNA results were abnormal if they were positive for SC aneuploidy (SCA), inconclusive, or discordant with ultrasound (US) findings. Primary outcome was concordance with karyotype or postnatal evaluation. Of 50 abnormal cfDNA results for SC, 31 patients (62%) were positive for SCA, 13 (26%) were inconclusive, and 6 (12%) were sex discordant on US. Of SCA results, 19 (61%) were reported as 45,X and 12 (39%) were SC trisomy. Abnormal karyotypes were confirmed in 8/23 (35%) of SC aneuploidy and 1/5 (20%) of inconclusive results. Abnormal SC cfDNA results were associated with in vitro fertilization (P = .001) and twins (P < .001). Sex discordance between cfDNA and US was associated with twin gestation (P < .001). In our cohort, abnormal SC cfDNA results were associated with in vitro fertilization and twins. Our results indicate cfDNA for sex prediction in twins of limited utility. Positive predictive value and sensitivity for SC determination were lower than previously reported. © 2017 John Wiley & Sons, Ltd.

Magnetic resonance imaging findings in pediatric bilateral vocal fold dysfunction.

PubMed

Steiner, Joel I; Fink, A Michelle; Berkowitz, Robert G

2013-07-01

We studied the findings of brain magnetic resonance imaging (MRI) in infants with idiopathic congenital bilateral vocal fold dysfunction (CBVFD). We performed a retrospective investigation of a case series. We identified 26 children (14 male, 12 female) over 11 years. Three children were excluded. Thirteen patients required airway interventions, including continuous positive airway pressure (4 patients), endotracheal intubation (1), and tracheostomy (8). The findings on brain MRI were abnormal in 8 patients (35%). Tracheostomy was required in 3 patients (38%) with abnormal MRI findings, as compared with 5 of 15 patients (33%) with normal MRI findings. The MRI abnormalities involved evidence of white matter injury (2), abnormal white matter signal (1), subdural blood (3), cerebral swelling (1), and perisylvian polymicrogyria (1). The cranial ultrasound findings were abnormal in 4 of 11 patients. The MRI findings were abnormal in 2 of 7 children in whom the cranial ultrasound findings were normal, and in 2 of the 4 patients in whom the cranial ultrasound findings were abnormal. The MRI abnormalities were nonspecific; however, they may indicate unrecognized perinatal intracranial injury as being related to CBVFD. In addition, MRI may reveal an underlying structural brain anomaly. Cranial ultrasound has poor sensitivity and specificity. Hence, MRI should be considered as part of the routine assessment of neonates with CBVFD.

A Role for Hypocretin/Orexin in Metabolic and Sleep Abnormalities in a Mouse Model of Non-metastatic Breast Cancer.

PubMed

Borniger, Jeremy C; Walker Ii, William H; Surbhi; Emmer, Kathryn M; Zhang, Ning; Zalenski, Abigail A; Muscarella, Stevie L; Fitzgerald, Julie A; Smith, Alexandra N; Braam, Cornelius J; TinKai, Tial; Magalang, Ulysses J; Lustberg, Maryam B; Nelson, Randy J; DeVries, A Courtney

2018-05-14

We investigated relationships among immune, metabolic, and sleep abnormalities in mice with non-metastatic mammary cancer. Tumor-bearing mice displayed interleukin-6 (IL-6)-mediated peripheral inflammation, coincident with altered hepatic glucose processing and sleep. Tumor-bearing mice were hyperphagic, had reduced serum leptin concentrations, and enhanced sensitivity to exogenous ghrelin. We tested whether these phenotypes were driven by inflammation using neutralizing monoclonal antibodies against IL-6; despite the reduction in IL-6 signaling, metabolic and sleep abnormalities persisted. We next investigated neural populations coupling metabolism and sleep, and observed altered activity within lateral-hypothalamic hypocretin/orexin (HO) neurons. We used a dual HO-receptor antagonist to test whether increased HO signaling was causing metabolic abnormalities. This approach rescued metabolic abnormalities and enhanced sleep quality in tumor-bearing mice. Peripheral sympathetic denervation prevented tumor-induced increases in serum glucose. Our results link metabolic and sleep abnormalities via the HO system, and provide evidence that central neuromodulators contribute to tumor-induced changes in metabolism. Copyright © 2018 Elsevier Inc. All rights reserved.

Cell cycle regulatory gene abnormalities are important determinants of leukemogenesis and disease biology in adult acute lymphoblastic leukemia.

PubMed

Stock, W; Tsai, T; Golden, C; Rankin, C; Sher, D; Slovak, M L; Pallavicini, M G; Radich, J P; Boldt, D H

2000-04-01

To test the hypothesis that cell cycle regulatory gene abnormalities are determinants of clinical outcome in adult acute lymphoblastic leukemia (ALL), we screened lymphoblasts from patients on a Southwest Oncology Group protocol for abnormalities of the genes, retinoblastoma (Rb), p53, p15(INK4B), and p16(INK4A). Aberrant expression occurred in 33 (85%) patients in the following frequencies: Rb, 51%; p16(INK4A), 41%; p53, 26%. Thirteen patients (33%) had abnormalities in 2 or more genes. Outcomes were compared in patients with 0 to 1 abnormality versus patients with multiple abnormalities. The 2 groups did not differ in a large number of clinical and laboratory characteristics. The CR rates for patients with 0 to 1 and multiple abnormalities were similar (69% and 54%, respectively). Patients with 0 to 1 abnormality had a median survival time of 25 months (n = 26; 95% CI, 13-46 months) versus 8 months (n = 13; 95% CI, 4-12 months) for those with multiple abnormalities (P <.01). Stem cells (CD34+lin-) were isolated from adult ALL bone marrows and tested for p16(INK4A) expression by immunocytochemistry. In 3 of 5 patients lymphoblasts and sorted stem cells lacked p16(INK4A) expression. In 2 other patients only 50% of sorted stem cells expressed p16(INK4A). By contrast, p16 expression was present in the CD34+ lin- compartment in 95% (median) of 9 patients whose lymphoblasts expressed p16(INK4A). Therefore, cell cycle regulatory gene abnormalities are frequently present in adult ALL lymphoblasts, and they may be important determinants of disease outcome. The presence of these abnormalities in the stem compartment suggests that they contribute to leukemogenesis. Eradication of the stem cell subset harboring these abnormalities may be important to achieve cure.

Sensitivity of technetium-99m-pyrophosphate scintigraphy in diagnosing cardiac amyloidosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falk, R.H.; Lee, V.W.; Rubinow, A.

1983-03-01

To determine the value of technetium-99m-pyrophosphate myocardial scintigraphy in the diagnosis of amyloid heart disease this procedure was prospectively performed in 20 consecutive patients with biopsy-proven primary amyloidosis. Eleven patients had echocardiographic abnormalities compatible with amyloid cardiomyopathy, 9 of whom had congestive heart failure. Diffuse myocardial pyrophosphate uptake was of equal or greater intensity than that of the ribs in 9 of the 11 patients with echocardiograms suggestive of amyloidosis, but in only 2 of the 9 with normal echocardiograms, despite abnormal electrocardiograms (p less than 0.01). Increased wall thickness measured by M-mode echocardiography correlated with myocardial pyrophosphate uptake (rmore » . 0.68, p less than 0.01). None of 10 control patients with nonamyloid, nonischemic heart disease had a strongly positive myocardial pyrophosphate uptake. Thus, myocardial technetium-99m-pyrophosphate scanning is a sensitive and specific test for the diagnosis of cardiac amyloidosis in patients with congestive heart failure of obscure origin. It does not appear to be of value for the early detection of cardiac involvement in patients with known primary amyloidosis without echocardiographic abnormalities.« less

Spatial contrast sensitivity - Effects of age, test-retest, and psychophysical method

NASA Technical Reports Server (NTRS)

Higgins, Kent E.; Jaffe, Myles J.; Caruso, Rafael C.; Demonasterio, Francisco M.

1988-01-01

Two different psychophysical methods were used to test the spatial contrast sensitivity in normal subjects from five age groups. The method of adjustment showed a decline in sensitivity with increasing age at all spatial frequencies, while the forced-choice procedure showed an age-related decline predominantly at high spatial frequencies. It is suggested that a neural component is responsible for this decline.

Body temperature sensitive micelles for MRI enhancement.

PubMed

Zhu, Xiaolei; Chen, Shizhen; Luo, Qing; Ye, Chaohui; Liu, Maili; Zhou, Xin

2015-06-04

A novel thermo-sensitive micelle contrast agent and its enhancement of MRI contrast with temperature are reported. The morphology changes sharply near 37 °C, resulting in a significant amplification of the CEST signal. This enables detection of small changes in body temperature.

[Acute kidney failure in infectious mononucleosis].

PubMed

Ramelli, G P; Marone, C; Truniger, B

1990-10-27

Overt renal disease is a rare complication of infectious mononucleosis (MI). In contrast, up to 16% of patients with MI have been shown to exhibit abnormalities in urinary sediment. Histological abnormalities--usually interstitial nephritis, and occasionally glomerular lesions--are rather common. Clinical symptoms include in rare cases isolated macrohematuria, occasionally a nephrotic or nephritic syndrome, and more commonly acute renal failure due to rhabdomyolysis, hepatorenal syndrome or acute interstitial nephritis. We report two observations of acute renal failure with a typically benign course and discuss these observations in the light of an updated literature survey of 34 patients.

Electrolyte changes in stroke.

PubMed

Alam, M N; Uddin, M J; Rahman, K M; Ahmed, S; Akhter, M; Nahar, N; Swapan, M K; Alam, M M; Sultana, N; Hallaz, M M; Alam, M M; Uddin, M M; Bari, M S; Israil, M A

2012-10-01

The present study was carried out in the department of Neurology and Medicine, Mymensingh Medical College Hospital, Bangladesh during the period of January 2009 to December 2010 to see the electrolyte changes in stroke. The serum concentration of Na⁺, K⁺, and Cl⁻ were measured in 110 cases during acute period of stroke (55 ischemic and 55 haemorrhagic strokes). Data were analyzed by computer with SPSS programme using 't' test and chi square test. In haemorrhagic stroke, out of 55 patients 29(52.72%) had abnormal sodium level, of them 23(41.8%) had hyponatremia, 6(10.9%) had hypernatremia. In contrast in ischemic stroke 23(41.80%) out of 55 had abnormal sodium level, of them 21(38%) had hyponatremia. The result showed that hyponatremia is almost equally common in both haemorrhagic and ischaemic group without significant difference (p>0.05). The study also revealed that hyponatremia is more common than hypernatremia in both groups. Mean ± SD of age of the haemorrhagic group was 60.80 ± 15.97 while the age of ischaemic group was 59.89 ± 15.84 years. Male, female ratio in haemorrhagic and ischaemic group 1:0.62 and 1:0.89 respectively. Mean ± SD of serum Na⁺, K⁺, Cl⁻ in haemorrhagic group were 136.18 ± 10.5, 3.83 ± 0.65, 97.96 ± 16.74 mmol/L, in ischaemic group 135.08 ± 9.08, 4.00 ± 0.75, 100.27 ± 8.39 mmol/L. The result showed no significant difference in haemorrhagic and ischemic stroke. Hyponatremia, hypokalamia and hyperchloredemia were more common than hypernatremia, hyperkalamia and hyperchloredemia. In haemorrhagic stroke, out of 55 patients, 21(38.18%) had abnormal potassium level, of them 19(34.55%) had hypokalemia, 2(3.63%) had hyperkalemia. In contrasts, in ischemic stroke, 15 out of 55(27.22%) had abnormal potassium level. Of them 12(21.81%) had hypokalemia and 3(5.45%) had hyperkalemia. The finding showed that hypokalemia is almost equally common in both haemorrhagic and ischaemic group without significant difference. The study also revealed that hypokalemia is more common than hyperkalemia in both groups. In haemorrhagic stroke, out of 55 patients 33(60%) had abnormal chloride level. Of them 20(36.4%) had hypochrloridemia, 13(23%) had hyperchrloridemia, in contrast, in ischemic stroke, 40 out of 55(60%) had abnormal chloride level, of them 22(40%) had hypochrloridemia and 18(32.7%) had hyperchrloridemia. The result showed that changes in chloride level after haemorrhagic and ischemic stroke are similar. The result showed hypochrloridemia is more common than hyperchrloridemia in both groups.

Improved sensitivity of computed tomography towards iodine and gold nanoparticle contrast agents via iterative reconstruction methods

PubMed Central

Bernstein, Ally Leigh; Dhanantwari, Amar; Jurcova, Martina; Cheheltani, Rabee; Naha, Pratap Chandra; Ivanc, Thomas; Shefer, Efrat; Cormode, David Peter

2016-01-01

Computed tomography is a widely used medical imaging technique that has high spatial and temporal resolution. Its weakness is its low sensitivity towards contrast media. Iterative reconstruction techniques (ITER) have recently become available, which provide reduced image noise compared with traditional filtered back-projection methods (FBP), which may allow the sensitivity of CT to be improved, however this effect has not been studied in detail. We scanned phantoms containing either an iodine contrast agent or gold nanoparticles. We used a range of tube voltages and currents. We performed reconstruction with FBP, ITER and a novel, iterative, modal-based reconstruction (IMR) algorithm. We found that noise decreased in an algorithm dependent manner (FBP > ITER > IMR) for every scan and that no differences were observed in attenuation rates of the agents. The contrast to noise ratio (CNR) of iodine was highest at 80 kV, whilst the CNR for gold was highest at 140 kV. The CNR of IMR images was almost tenfold higher than that of FBP images. Similar trends were found in dual energy images formed using these algorithms. In conclusion, IMR-based reconstruction techniques will allow contrast agents to be detected with greater sensitivity, and may allow lower contrast agent doses to be used. PMID:27185492

High-resolution contrast-enhanced optical coherence tomography in mice retinae

NASA Astrophysics Data System (ADS)

Sen, Debasish; SoRelle, Elliott D.; Liba, Orly; Dalal, Roopa; Paulus, Yannis M.; Kim, Tae-Wan; Moshfeghi, Darius M.; de la Zerda, Adam

2016-06-01

Optical coherence tomography (OCT) is a noninvasive interferometric imaging modality providing anatomical information at depths of millimeters and a resolution of micrometers. Conventional OCT images limit our knowledge to anatomical structures alone, without any contrast enhancement. Therefore, here we have, for the first time, optimized an OCT-based contrast-enhanced imaging system for imaging single cells and blood vessels in vivo inside the living mouse retina at subnanomolar sensitivity. We used bioconjugated gold nanorods (GNRs) as exogenous OCT contrast agents. Specifically, we used anti-mouse CD45 coated GNRs to label mouse leukocytes and mPEG-coated GNRs to determine sensitivity of GNR detection in vivo inside mice retinae. We corroborated OCT observations with hyperspectral dark-field microscopy of formalin-fixed histological sections. Our results show that mouse leukocytes that otherwise do not produce OCT contrast can be labeled with GNRs leading to significant OCT intensity equivalent to a 0.5 nM GNR solution. Furthermore, GNRs injected intravenously can be detected inside retinal blood vessels at a sensitivity of ˜0.5 nM, and GNR-labeled cells injected intravenously can be detected inside retinal capillaries by enhanced OCT contrast. We envision the unprecedented resolution and sensitivity of functionalized GNRs coupled with OCT to be adopted for longitudinal studies of retinal disorders.

Detection of breast cancer in automated 3D breast ultrasound

NASA Astrophysics Data System (ADS)

Tan, Tao; Platel, Bram; Mus, Roel; Karssemeijer, Nico

2012-03-01

Automated 3D breast ultrasound (ABUS) is a novel imaging modality, in which motorized scans of the breasts are made with a wide transducer through a membrane under modest compression. The technology has gained high interest and may become widely used in screening of dense breasts, where sensitivity of mammography is poor. ABUS has a high sensitivity for detecting solid breast lesions. However, reading ABUS images is time consuming, and subtle abnormalities may be missed. Therefore, we are developing a computer aided detection (CAD) system to help reduce reading time and errors. In the multi-stage system we propose, segmentations of the breast and nipple are performed, providing landmarks for the detection algorithm. Subsequently, voxel features characterizing coronal spiculation patterns, blobness, contrast, and locations with respect to landmarks are extracted. Using an ensemble of classifiers, a likelihood map indicating potential malignancies is computed. Local maxima in the likelihood map are determined using a local maxima detector and form a set of candidate lesions in each view. These candidates are further processed in a second detection stage, which includes region segmentation, feature extraction and a final classification. Region segmentation is performed using a 3D spiral-scanning dynamic programming method. Region features include descriptors of shape, acoustic behavior and texture. Performance was determined using a 78-patient dataset with 93 images, including 50 malignant lesions. We used 10-fold cross-validation. Using FROC analysis we found that the system obtains a lesion sensitivity of 60% and 70% at 2 and 4 false positives per image respectively.

Sensitive biomarkers of alcoholism's effect on brain macrostructure: similarities and differences between France and the United States

PubMed Central

Le Berre, Anne-Pascale; Pitel, Anne-Lise; Chanraud, Sandra; Beaunieux, Hélène; Eustache, Francis; Martinot, Jean-Luc; Reynaud, Michel; Martelli, Catherine; Rohlfing, Torsten; Pfefferbaum, Adolf; Sullivan, Edith V.

2015-01-01

Alcohol consumption patterns and recognition of health outcomes related to hazardous drinking vary widely internationally, raising the question whether these national differences are reflected in brain damage observed in alcoholism. This retrospective analysis assessed variability of alcoholism's effects on brain cerebrospinal fluid (CSF) and white matter volumes between France and the United States (U.S.). MRI data from two French sites (Caen and Orsay) and a U.S. laboratory (SRI/Stanford University) were acquired on 1.5T imaging systems in 287 controls, 165 uncomplicated alcoholics (ALC), and 26 alcoholics with Korsakoff's Syndrome (KS). All data were analyzed at the U.S. site using atlas-based parcellation. Results revealed graded CSF volume enlargement from ALC to KS and white matter volume deficits in KS only. In ALC from France but not the U.S., CSF and white matter volumes correlated with lifetime alcohol consumption, alcoholism duration, and length of sobriety. MRI highlighted CSF volume enlargement in both ALC and KS, serving as a basis for an ex vacuo process to explain correlated gray matter shrinkage. By contrast, MRI provided a sensitive in vivo biomarker of white matter volume shrinkage in KS only, suggesting a specific process sensitive to mechanisms contributing to Wernicke's encephalopathy, the precursor of KS. Identified structural brain abnormalities may provide biomarkers underlying alcoholism's heterogeneity in and among nations and suggest a substrate of gray matter tissue shrinkage. Proposed are hypotheses for national differences in interpreting whether the severity of sequelae observe a graded phenomenon or a continuum from uncomplicated alcoholism to alcoholism complicated by KS. PMID:26157376

Intratumoral genetic heterogeneity in metastatic melanoma is accompanied by variation in malignant behaviors

PubMed Central

2013-01-01

Background Intratumoral heterogeneity is a major obstacle for the treatment of cancer, as the presence of even minor populations that are insensitive to therapy can lead to disease relapse. Increased clonal diversity has been correlated with a poor prognosis for cancer patients, and we therefore examined genetic, transcriptional, and functional diversity in metastatic melanoma. Methods Amplicon sequencing and SNP microarrays were used to profile somatic mutations and DNA copy number changes in multiple regions from metastatic lesions. Clonal genetic and transcriptional heterogeneity was also assessed in single cell clones from early passage cell lines, which were then subjected to clonogenicity and drug sensitivity assays. Results MAPK pathway and tumor suppressor mutations were identified in all regions of the melanoma metastases analyzed. In contrast, we identified copy number abnormalities present in only some regions in addition to homogeneously present changes, suggesting ongoing genetic evolution following metastatic spread. Copy number heterogeneity from a tumor was represented in matched cell line clones, which also varied in their clonogenicity and drug sensitivity. Minor clones were identified based on dissimilarity to the parental cell line, and these clones were the most clonogenic and least sensitive to drugs. Finally, treatment of a polyclonal cell line with paclitaxel to enrich for drug-resistant cells resulted in the adoption of a gene expression profile with features of one of the minor clones, supporting the idea that these populations can mediate disease relapse. Conclusion Our results support the hypothesis that minor clones might have major consequences for patient outcomes in melanoma. PMID:24119551

DNA-dependent protein kinase (DNA-PK)-deficient human glioblastoma cells are preferentially sensitized by Zebularine

PubMed Central

Meador, Jarah A.; Su, Yanrong; Ravanat, Jean-Luc; Balajee, Adayabalam S.

2010-01-01

Brain tumor cells respond poorly to radiotherapy and chemotherapy due to inherently efficient anti-apoptotic and DNA repair mechanisms. This necessitates the development of new strategies for brain cancer therapy. Here, we report that the DNA-demethylating agent Zebularine preferentially sensitizes the killing of human glioblastomas deficient in DNA-dependent protein kinase (DNA-PK). In contrast to DNA-PK-proficient human glioblastoma cells (MO59K), cytotoxicity assay with increasing Zebularine concentrations up to 300 μM resulted in a specific elevation of cell killing in DNA-PK-deficient MO59J cells. Further, an elevated frequency of polyploid cells observed in MO59J cells after Zebularine treatment pointed out a deficiency in mitotic checkpoint control. Existence of mitotic checkpoint deficiency in MO59J cells was confirmed by the abnormal centrosome number observed in Zebularine-treated MO59J cells. Although depletion of DNA methyltransferase 1 by Zebularine occurred at similar levels in both cell lines, MO59J cells displayed increased extent of DNA demethylation detected both at the gene promoter-specific level and at the genome overall level. Consistent with increased sensitivity, deoxy-Zebularine adduct level in the genomic DNA was 3- to 6-fold higher in MO59J than in MO59K cells. Elevated micronuclei frequency observed after Zebularine treatment in MO59J cells indicates the impairment of DNA repair response in MO59J cells. Collectively, our study suggests that DNA-PK is the major determining factor for cellular response to Zebularine. PMID:19933707

Detection of Cardiac Abnormalities from Multilead ECG using Multiscale Phase Alternation Features.

PubMed

Tripathy, R K; Dandapat, S

2016-06-01

The cardiac activities such as the depolarization and the relaxation of atria and ventricles are observed in electrocardiogram (ECG). The changes in the morphological features of ECG are the symptoms of particular heart pathology. It is a cumbersome task for medical experts to visually identify any subtle changes in the morphological features during 24 hours of ECG recording. Therefore, the automated analysis of ECG signal is a need for accurate detection of cardiac abnormalities. In this paper, a novel method for automated detection of cardiac abnormalities from multilead ECG is proposed. The method uses multiscale phase alternation (PA) features of multilead ECG and two classifiers, k-nearest neighbor (KNN) and fuzzy KNN for classification of bundle branch block (BBB), myocardial infarction (MI), heart muscle defect (HMD) and healthy control (HC). The dual tree complex wavelet transform (DTCWT) is used to decompose the ECG signal of each lead into complex wavelet coefficients at different scales. The phase of the complex wavelet coefficients is computed and the PA values at each wavelet scale are used as features for detection and classification of cardiac abnormalities. A publicly available multilead ECG database (PTB database) is used for testing of the proposed method. The experimental results show that, the proposed multiscale PA features and the fuzzy KNN classifier have better performance for detection of cardiac abnormalities with sensitivity values of 78.12 %, 80.90 % and 94.31 % for BBB, HMD and MI classes. The sensitivity value of proposed method for MI class is compared with the state-of-art techniques from multilead ECG.

The Puzzle of Visual Development: Behavior and Neural Limits.

PubMed

Kiorpes, Lynne

2016-11-09

The development of visual function takes place over many months or years in primate infants. Visual sensitivity is very poor near birth and improves over different times courses for different visual functions. The neural mechanisms that underlie these processes are not well understood despite many decades of research. The puzzle arises because research into the factors that limit visual function in infants has found surprisingly mature neural organization and adult-like receptive field properties in very young infants. The high degree of visual plasticity that has been documented during the sensitive period in young children and animals leaves the brain vulnerable to abnormal visual experience. Abnormal visual experience during the sensitive period can lead to amblyopia, a developmental disorder of vision affecting ∼3% of children. This review provides a historical perspective on research into visual development and the disorder amblyopia. The mismatch between the status of the primary visual cortex and visual behavior, both during visual development and in amblyopia, is discussed, and several potential resolutions are considered. It seems likely that extrastriate visual areas further along the visual pathways may set important limits on visual function and show greater vulnerability to abnormal visual experience. Analyses based on multiunit, population activity may provide useful representations of the information being fed forward from primary visual cortex to extrastriate processing areas and to the motor output. Copyright © 2016 the authors 0270-6474/16/3611384-10$15.00/0.

Modelling the dependence of contrast sensitivity on grating area and spatial frequency.

PubMed

Rovamo, J; Luntinen, O; Näsänen, R

1993-12-01

We modelled the human foveal visual system in a detection task as a simple image processor comprising (i) low-pass filtering due to the optical transfer function of the eye, (ii) high-pass filtering of neural origin, (iii) addition of internal neural noise, and (iv) detection by a local matched filter. Its detection efficiency for gratings was constant up to a critical area but then decreased with increasing area. To test the model we measured Michelson contrast sensitivity as a function of grating area at spatial frequencies of 0.125-32 c/deg for simple vertical and circular cosine gratings. In circular gratings luminance was sinusoidally modulated as a function of the radius of the grating field. In agreement with the model, contrast sensitivity at all spatial frequencies increased in proportion to the square-root of grating area at small areas. When grating area exceeded critical area, the increase saturated and contrast sensitivity became independent of area at large grating areas. Spatial integration thus obeyed Piper's law at small grating areas. The critical area of spatial integration, marking the cessation of Piper's law, was constant in solid degrees at low spatial frequencies but inversely proportional to spatial frequency squared at medium and high spatial frequencies. At low spatial frequencies the maximum contrast sensitivity obtainable by spatial integration increased in proportion to spatial frequency but at high spatial frequencies it decreased in proportion to the cube of the increasing spatial frequency. The increase was due to high-pass filtering of neural origin (lateral inhibition) and the decrease was mainly due to the optical transfer function of the eye. Our model explained 95% of the total variance of the contrast sensitivity data.

Longitudinal study of visual function in patients with relapsing-remitting multiple sclerosis with and without a history of optic neuritis.

PubMed

González Gómez, A; García-Ben, A; Soler García, A; García-Basterra, I; Padilla Parrado, F; García-Campos, J M

2017-03-15

The contrast sensitivity test determines the quality of visual function in patients with multiple sclerosis (MS). The purpose of this study is to analyse changes in visual function in patients with relapsing-remitting MS with and without a history of optic neuritis (ON). We conducted a longitudinal study including 61 patients classified into 3 groups as follows: a) disease-free patients (control group); b) patients with MS and no history of ON; and c) patients with MS and a history of unilateral ON. All patients underwent baseline and 6-year follow-up ophthalmologic examinations, which included visual acuity and monocular and binocular Pelli-Robson contrast sensitivity tests. Monocular contrast sensitivity was significantly lower in MS patients with and without a history of ON than in controls both at baseline (P=.00 and P=.01, respectively) and at 6 years (P=.01 and P=.02). Patients with MS and no history of ON remained stable throughout follow-up whereas those with a history of ON displayed a significant loss of contrast sensitivity (P=.01). Visual acuity and binocular contrast sensitivity at baseline and at 6 years was significantly lower in the group of patients with a history of ON than in the control group (P=.003 and P=.002 vs P=.006 and P=.005) and the group with no history of ON (P=.04 and P=.038 vs P=.008 and P=.01). However, no significant differences were found in follow-up results (P=.1 and P=.5). Monocular Pelli-Robson contrast sensitivity test may be used to detect changes in visual function in patients with ON. Copyright © 2017 The Author(s). Publicado por Elsevier España, S.L.U. All rights reserved.

Changes in color vision and contrast sensitivity after descemet membrane endothelial keratoplasty for fuchs endothelial dystrophy.

PubMed

Cabrerizo, Javier; Livny, Eitan; Musa, Fayyaz U; Leeuwenburgh, Paulien; van Dijk, Korine; Melles, Gerrit R J

2014-10-01

The aim of this study is to evaluate contrast sensitivity, color vision, and subjective patient satisfaction after Descemet membrane endothelial keratoplasty (DMEK) in patients with bilateral Fuchs endothelial dystrophy (FED). From a group of 500 DMEK surgeries performed in our center, patients with a history of bilateral FED and unilateral DMEK were identified. A total of 29 patients were included in the study and divided into 2 groups: phakic (n = 12) and pseudophakic unilateral DMEK (n = 17) and their contralateral, untreated FED-affected eye. In addition, a control group of 10 healthy eyes of 10 patients was included. Pelli-Robson contrast sensitivity and Farnsworth-Munsell 100 hue color vision tests were performed. Subjective optical quality was graded with a questionnaire. Compared with untreated FED-affected eyes, best spectacle-corrected visual acuity was higher after DMEK in phakic and pseudophakic eyes (P = 0.030 and P < 0.001, respectively); a similar result was obtained for contrast sensitivity (P < 0.001 and P < 0.001, respectively). Color vision did not differ between untreated FED-affected and DMEK-operated eyes in the phakic group (P = 0.802) and the pseudophakic group (P = 0.227). Subjective optical quality was better in DMEK-operated eyes than in untreated FED-affected eyes in the phakic group (P < 0.001) and in the pseudophakic group (P < 0.001). In FED, DMEK may not only be effective for obtaining a higher visual acuity but particularly improving the contrast sensitivity may also lead to better subjective optical performance. Although frequently mentioned spontaneously by patients, an objective change in color vision could not be substantiated. Hence, quantifying contrast sensitivity before surgery may aid in the decision for surgery, and in the evaluation of surgical outcome.

Diagnosis of non-occlusive acute mesenteric ischemia in the intensive care unit.

PubMed

Bourcier, Simon; Oudjit, Ammar; Goudard, Geoffrey; Charpentier, Julien; Leblanc, Sarah; Coriat, Romain; Gouya, Hervé; Dousset, Bertrand; Mira, Jean-Paul; Pène, Frédéric

2016-12-01

Non-occlusive mesenteric ischemia (NOMI) is a common complication and accounts for a major cause of death in critically ill patients. The diagnosis of NOMI with respect to the eventual indications for surgical treatment is challenging. We addressed the performance of the diagnostic strategy of NOMI in the intensive care unit, with emphasis on contrast-enhanced abdominal CT-scan. This was a retrospective monocenter study. Patients with clinically suspected acute mesenteric ischemia were included if a comprehensive diagnostic workup was carried out including surgical and/or endoscopic digestive explorations. Patients with evidence of occlusive mesenteric ischemia were excluded. A definite diagnosis of NOMI only relied on surgical or endoscopic findings. Abdominal CT-scans were reviewed by two radiologists blinded from the final diagnosis. A diagnosis of NOMI could be definitely confirmed or ruled out through surgical or endoscopic explorations of the digestive tract in 147 patients. With respect to their clinical characteristics, only a history of atrial fibrillation was an independent predictor of NOMI (odds ratio 8.3, 95% confidence interval 2.0-35.2, p = 0.004). Among them, 114 patients (75 with and 39 without NOMI) had previously been subjected to contrast-enhanced abdominal CT-scan. Portal venous gas, pneumatosis intestinalis and, to a lesser extent, abnormal contrast-induced bowel wall enhancement were poorly sensitive, but exhibited good specificities of 95, 85 and 71%, respectively. Nineteen out of 75 patients (25.3%) without any suggestive radiological signs finally exhibited mesenteric ischemia, including ten with intestinal necrosis. The performance of abdominal CT-scan for the diagnosis of NOMI is limited. Radiological signs of advanced-stage ischemia are good predictors of definite mesenteric ischemia, while their absence should not be considered sufficient to rule out the diagnosis.

Role of scintigraphy in urinary tract infection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conway, J.J.

1988-10-01

There is controversy regarding the role of radiological imaging for urinary tract infection (UTI). The gold standard has been the intravenous pyelogram (IVP). Yet, the IVP has a very limited value with only about 25% of children with pyelonephritis demonstrating abnormalities. Ultrasound (US) has recently been advocated as a replacement for the poorly sensitive and poorly specific IVP. However, comparative studies between US and IVP indicate only an equivalent sensitivity and specificity. Cortical scintigraphy with Technetium-99m glucoheptonate (99mTc GH) or 99mTc dimercaptosuccinic acid (99mTc DMSA) has also been advocated as a means of differentiating parenchymal (pyelonephritis) from nonparenchymal (lower UTI)more » involvement in UTI. The clinical presentation may be misleading especially in the infant and child in whom an elevated temperature, flank pain, shaking chills, or an elevated sedimentation rate are often lacking. The clinician attempts to localize the site of infection for it has a direct bearing upon the therapy. A collecting system infection can often be eradicated with a single oral dose of an appropriate antibiotic, whereas renal parenchymal involvement requires IV therapy for an extended interval. Cortical scintigraphy can localize the site of infection with a high degree of accuracy. Recent studies report a sensitivity of 86% and specificity of 81% of pyelonephritis. This is in contrast to the IVP with a sensitivity of only 24% and US with a sensitivity of only 42%. The scintigraphic appearance of parenchymal infection of the kidney is a spectrum of minimal to gross defects reflecting the degree of histologic involvement that spans from a mild infection to frank abscess. Cortical scintigraphy can be used to monitor the evolution of scarring following infection. Cortical scintigraphy with 99mTc DMSA or 99mTc GH is the method of choice for the initial evaluation of UTI. 37 references.« less

Evaluation of the Effects of Conjunctivochalasis Excision on Tear Stability and Contrast Sensitivity

PubMed Central

Qiu, Weiqiang; Zhang, Mingzhou; Xu, Ting; Liu, Ziyuan; Lv, Huibin; Wang, Wei; Li, Xuemin

2016-01-01

Conjunctivochalasis (CCh) disrupts tear flow and damages tear film stability. This study sought to evaluate the tear stability and contrast sensitivity of patients with CCh on whom CCh excision was performed. The study included 39 eyes from 39 patients; all patients had eyes with grade 2 or 3 CCh, underwent CCh excision, and were evaluated before and three months after the surgery. The evaluated variables included the ocular surface disease index (OSDI), the tear break-up time (TBUT), corneal fluorescein staining, corneal surface irregularity, Schirmer’s I test, the tear meniscus area (TMA), and contrast sensitivity. A follow-up of three months was achieved in 36 eyes for 36 patients. All parameters improved significantly after surgery (p < 0.05), except Schirmer’s I test, thus suggesting that CCh excision is an effective method for reconstructing the lower tear meniscus and improving both tear film stability and corneal surface irregularity. The results further demonstrated a simultaneous increase in contrast sensitivity after surgery. PMID:27892479

Clinical and microperimetric predictors of reading speed in low vision patients: a structural equation modeling approach.

PubMed

Giacomelli, Giovanni; Virgili, Gianni; Giansanti, Fabrizio; Sato, Giovanni; Cappello, Ezio; Cruciani, Filippo; Varano, Monica; Menchini, Ugo

2013-06-27

To investigate the simultaneous association of several psychophysical measures with reading ability in patients with mild and moderate low vision attending rehabilitation services. Standard measurements of reading ability (Minnesota Reading [MNREAD] charts), visual acuity (Early Treatment of Diabetic Retinopathy Study [ETDRS] charts), contrast sensitivity (Pelli-Robson charts), reading contrast threshold (Reading Explorer [REX] charts), retinal sensitivity, and fixation stability and localization (Micro Perimeter 1 [MP1] fundus perimetry) were obtained in 160 low vision patients with better eye visual acuity ranging from 0.3 to 1.0 logarithm of the minimum angle of resolution and affected by either age-related macular degeneration or diabetic retinopathy. All variables were moderately associated with reading performance measures (MNREAD reading speed and reading acuity and REX reading contrast threshold), as well as among each other. In a structural equation model, REX reading contrast threshold was highly associated with MNREAD reading speed (standardized coefficient, 0.63) and moderately associated with reading acuity (standardized coefficient, -0.30). REX test also mediated the effects of Pelli-Robson contrast sensitivity (standardized coefficient, 0.44), MP1 fixation eccentricity (standardized coefficient, -0.19), and the mean retinal sensitivity (standardized coefficient, 0.23) on reading performance. The MP1 fixation stability was associated with both MNREAD reading acuity (standardized coefficient, -0.24) and MNREAD reading speed (standardized coefficient, 0.23), while ETDRS visual acuity only affected reading acuity (standardized coefficient, 0.44). Fixation instability and contrast sensitivity loss are key factors limiting reading performance of patients with mild or moderate low vision. REX charts directly assess the impact of text contrast on letter recognition and text navigation and may be a useful aid in reading rehabilitation.

Cervical Cancer Risk for 330,000 Women Undergoing Concurrent HPV Testing and Cervical Cytology in Routine Clinical Practice at a Large Managed Care Organization

PubMed Central

Katki, Hormuzd A.; Kinney, Walter K.; Fetterman, Barbara; Lorey, Thomas; Poitras, Nancy E.; Cheung, Li; Demuth, Franklin; Schiffman, Mark; Wacholder, Sholom; Castle, Philip E.

2011-01-01

Background Concurrent HPV testing and cervical cytology (co-testing) is an approved and promising alternative to cytology alone in women aged 30 and older. However, broad acceptance of co-testing is being hindered by a lack of evidence about its performance in routine clinical practice. We evaluated the safety of three-year screening intervals for women testing HPV-negative with normal cytology (Pap-negative) and assessed the ability of co-testing to identify women at high risk of CIN3+ or cervical cancer over five years. Methods We analyzed five-year cumulative incidence of cervical cancer and cervical intraepithelial neoplasia grade 3 or worse (CIN3+) for 331,818 women aged 30 and older who enrolled in co-testing at Kaiser Permanente Northern California starting 2003-2005 (and had adequate enrollment co-test results) and were followed through December 31, 2009. Findings Five-year cumulative incidence of cancer for all 315,061 HPV-negative women was extremely low (3.8 per 100,000 women per year), only slightly higher than for the 306,969 women who were both HPV-negative and Pap-negative (3.2 per 100,000 women per year), and half the cancer risk of all 319,177 women who were Pap-negative (7.5 per 100,000 women per year). Almost all (99.5%; 313,465) HPV-negative women had either normal cytology or minor abnormalities. Abnormal cytology greatly increased cumulative incidence of CIN3+ over five years for the 16,757 HPV-positive women (12% vs. 5.9%, p<0.0001). In contrast, although statistically significant, abnormal cytology did not increase 5-year CIN3+ risk for HPV-negative women to a substantial level (0.86% vs. 0.16%). 73% of HPV-positive women had no cytologic abnormality (12,208 women). HPV-positive women with no cytologic abnormality experienced 34% of the CIN3+, 29% of the cancers, and 63% of the adenocarcinomas. Interpretation For women aged 30 and older in routine clinical practice, a single negative HPV test sufficed to provide strong reassurance against cervical cancer over five years, demonstrating the safety of 3-year screening intervals for HPV-negative/Pap-negative women and suggesting that five-year intervals may also be safe. Concurrent HPV testing resulted in earlier identification of the women at high risk of cervical cancer, especially adenocarcinoma. HPV testing without adjunctive cytology may be sufficiently sensitive for primary cervical cancer screening. PMID:21684207

Effects of Neonatal Dexamethasone Exposure on Adult Neuropsychiatric Traits in Rats

PubMed Central

Robertson, Donald; Rodger, Jennifer; Martin-Iverson, Mathew T.

2016-01-01

The effects of early life stress in utero or in neonates has long-term consequences on hypothalamic-pituitary-adrenal (HPA) stress axis function and neurodevelopment. These effects extend into adulthood and may underpin a variety of mental illnesses and be related to various developmental and cognitive changes. We examined the potential role of neonatal HPA axis activation on adult psychopathology and dopamine sensitivity in the mature rat using neonatal exposure to the synthetic glucocorticoid receptor agonist and stress hormone, dexamethasone. We utilized a comprehensive battery of assessments for behaviour, brain function and gene expression to determine if elevated early life HPA activation is associated with adult-onset neuropsychiatric traits. Dexamethasone exposure increased startle reactivity under all conditions tested, but decreased sensitivity of sensorimotor gating to dopaminergic disruption–contrasting with what is observed in several neuropsychiatric diseases. Under certain conditions there also appeared to be mild long-term changes in stress and anxiety-related behaviours with neonatal dexamethasone exposure. Electrophysiology revealed that there were no consistent neuropsychiatric abnormalities in auditory processing or resting state brain function with dexamethasone exposure. However, neonatal dexamethasone altered auditory cortex glucocorticoid activation, and auditory cortex synchronization. Our results indicate that neonatal HPA axis activation by dexamethasone alters several aspects of adult brain function and behaviour and may induce long-term changes in emotional stress-reactivity. However, neonatal dexamethasone exposure is not specifically related to any particular neuropsychiatric disease. PMID:27936175

Undercarboxylated osteocalcin is associated with insulin resistance, but not adiponectin, during pregnancy.

PubMed

Srichomkwun, Panudda; Houngngam, Natnicha; Pasatrat, Sophitsachi; Tharavanij, Thipaporn; Wattanachanya, Lalita; Khovidhunkit, Weerapan

2016-07-01

In mice, undercarboxylated osteocalcin (ucOC) improves beta-cell function and insulin sensitivity through adiponectin. In humans, levels of total osteocalcin (OC) and ucOC were negatively correlated with insulin resistance (IR) indices in patients with type 2 diabetes. Whether ucOC plays a role in glucose homeostasis and whether its effect is mediated through adiponectin during pregnancy is unclear. Serum levels of total OC, ucOC, and adiponectin were measured in 130 pregnant women with varying degrees of IR [gestational diabetes mellitus (GDM), n = 74 and non-GDM, n = 56]. In all participants, total OC and ucOC levels were positively correlated with HOMA-IR and HOMA-%B, and negatively correlated with QUICKI. In contrast, adiponectin levels were negatively correlated with HOMA-IR and positively correlated with QUICKI (P < 0.01, both). However, neither total OC nor ucOC was associated with adiponectin. Although none of these markers could help distinguish women with and without GDM, total OC and ucOC levels were significantly higher in non-GDM women who had 1 abnormal OGTT value than those who had all normal OGTT values. Total OC and ucOC levels were significantly correlated with insulin secretion and IR indices, but not adiponectin levels, in pregnant women. Changes in OC might be a sensitive response to increased IR during pregnancy, which was not mediated through adiponectin.

Astrocytes reverted to a neural progenitor-like state with transforming growth factor alpha are sensitized to cancerous transformation

PubMed Central

Dufour, Christelle; Cadusseau, Josette; Varlet, Pascale; Surena, Anne-Laure; De Faria, Giselle P; Dias-Morais, Amelie; Auger, Nathalie; Léonard, Nadine; Daudigeos, Estelle; Dantas-Barbosa, Carmela; Grill, Jacques; Lazar, Vladimir; Dessen, Philippe; Vassal, Gilles; Prevot, Vincent; Sharif, Ariane; Chneiweiss, Hervé; Junier, Marie-Pierre

2009-01-01

Gliomas, the most frequent primitive CNS tumors, have been suggested to originate from astrocytes or from neural progenitors/stem cells. However, the precise identity of the cells at the origin of gliomas remains a matter of debate because no pre-neoplastic state has been yet identified. TGFα, an EGF family member, is frequently over-expressed in the early stages of glioma progression. We previously demonstrated that prolonged exposure of astrocytes to TGFα is sufficient to trigger their reversion to a neural progenitor-like state. To determine whether TGFα de-differentiating effects are associated with cancerous transforming effects, we grafted intra-cerebrally de-differentiated astrocytes. We show that these cells had the same cytogenomic profile as astrocytes, survived in vivo and did not give birth to tumors. When astrocytes de-differentiated with TGFα were submitted to oncogenic stress using gamma irradiation, they acquired cancerous properties: they were immortalized, showed cytogenomic abnormalities, and formed high-grade glioma-like tumors after brain grafting. In contrast, irradiation did not modify the lifespan of astrocytes cultivated in serum-free medium. Addition of TGFα after irradiation did not promote their transformation but decreased their lifespan. These results demonstrate that reversion of mature astrocytes to an embryonic state without genomic manipulation is sufficient to sensitize them to oncogenic stress. PMID:19544474

Color, contrast sensitivity, and the cone mosaic.

PubMed Central

Williams, D; Sekiguchi, N; Brainard, D

1993-01-01

This paper evaluates the role of various stages in the human visual system in the detection of spatial patterns. Contrast sensitivity measurements were made for interference fringe stimuli in three directions in color space with a psychophysical technique that avoided blurring by the eye's optics including chromatic aberration. These measurements were compared with the performance of an ideal observer that incorporated optical factors, such as photon catch in the cone mosaic, that influence the detection of interference fringes. The comparison of human and ideal observer performance showed that neural factors influence the shape as well as the height of the foveal contrast sensitivity function for all color directions, including those that involve luminance modulation. Furthermore, when optical factors are taken into account, the neural visual system has the same contrast sensitivity for isoluminant stimuli seen by the middle-wavelength-sensitive (M) and long-wavelength-sensitive (L) cones and isoluminant stimuli seen by the short-wavelength-sensitive (S) cones. Though the cone submosaics that feed these chromatic mechanisms have very different spatial properties, the later neural stages apparently have similar spatial properties. Finally, we review the evidence that cone sampling can produce aliasing distortion for gratings with spatial frequencies exceeding the resolution limit. Aliasing can be observed with gratings modulated in any of the three directions in color space we used. We discuss mechanisms that prevent aliasing in most ordinary viewing conditions. Images Fig. 1 Fig. 8 PMID:8234313

Human Vision-Motivated Algorithm Allows Consistent Retinal Vessel Classification Based on Local Color Contrast for Advancing General Diagnostic Exams.

PubMed

Ivanov, Iliya V; Leitritz, Martin A; Norrenberg, Lars A; Völker, Michael; Dynowski, Marek; Ueffing, Marius; Dietter, Johannes

2016-02-01

Abnormalities of blood vessel anatomy, morphology, and ratio can serve as important diagnostic markers for retinal diseases such as AMD or diabetic retinopathy. Large cohort studies demand automated and quantitative image analysis of vascular abnormalities. Therefore, we developed an analytical software tool to enable automated standardized classification of blood vessels supporting clinical reading. A dataset of 61 images was collected from a total of 33 women and 8 men with a median age of 38 years. The pupils were not dilated, and images were taken after dark adaption. In contrast to current methods in which classification is based on vessel profile intensity averages, and similar to human vision, local color contrast was chosen as a discriminator to allow artery vein discrimination and arterial-venous ratio (AVR) calculation without vessel tracking. With 83% ± 1 standard error of the mean for our dataset, we achieved best classification for weighted lightness information from a combination of the red, green, and blue channels. Tested on an independent dataset, our method reached 89% correct classification, which, when benchmarked against conventional ophthalmologic classification, shows significantly improved classification scores. Our study demonstrates that vessel classification based on local color contrast can cope with inter- or intraimage lightness variability and allows consistent AVR calculation. We offer an open-source implementation of this method upon request, which can be integrated into existing tool sets and applied to general diagnostic exams.

Postnatal Developmental Trajectories of Neural Circuits in the Primate Prefrontal Cortex: Identifying Sensitive Periods for Vulnerability to Schizophrenia

PubMed Central

Hoftman, Gil D.; Lewis, David A.

2011-01-01

Schizophrenia is a disorder of cognitive neurodevelopment with characteristic abnormalities in working memory attributed, at least in part, to alterations in the circuitry of the dorsolateral prefrontal cortex. Various environmental exposures from conception through adolescence increase risk for the illness, possibly by altering the developmental trajectories of prefrontal cortical circuits. Macaque monkeys provide an excellent model system for studying the maturation of prefrontal cortical circuits. Here, we review the development of glutamatergic and γ-aminobutyric acid (GABA)-ergic circuits in macaque monkey prefrontal cortex and discuss how these trajectories may help to identify sensitive periods during which environmental exposures, such as those associated with increased risk for schizophrenia, might lead to the types of abnormalities in prefrontal cortical function present in schizophrenia. PMID:21505116

Brainstem timing: implications for cortical processing and literacy.

PubMed

Banai, Karen; Nicol, Trent; Zecker, Steven G; Kraus, Nina

2005-10-26

The search for a unique biological marker of language-based learning disabilities has so far yielded inconclusive findings. Previous studies have shown a plethora of auditory processing deficits in learning disabilities at both the perceptual and physiological levels. In this study, we investigated the association among brainstem timing, cortical processing of stimulus differences, and literacy skills. To that end, brainstem timing and cortical sensitivity to acoustic change [mismatch negativity (MMN)] were measured in a group of children with learning disabilities and normal-learning children. The learning-disabled (LD) group was further divided into two subgroups with normal and abnormal brainstem timing. MMNs, literacy, and cognitive abilities were compared among the three groups. LD individuals with abnormal brainstem timing were more likely to show reduced processing of acoustic change at the cortical level compared with both normal-learning individuals and LD individuals with normal brainstem timing. This group was also characterized by a more severe form of learning disability manifested by poorer reading, listening comprehension, and general cognitive ability. We conclude that abnormal brainstem timing in learning disabilities is related to higher incidence of reduced cortical sensitivity to acoustic change and to deficient literacy skills. These findings suggest that abnormal brainstem timing may serve as a reliable marker of a subgroup of individuals with learning disabilities. They also suggest that faulty mechanisms of neural timing at the brainstem may be the biological basis of malfunction in this group.

Synthesis and characterization of a smart contrast agent sensitive to calcium.

PubMed

Dhingra, Kirti; Maier, Martin E; Beyerlein, Michael; Angelovski, Goran; Logothetis, Nikos K

2008-08-07

A novel first-generation Ca2+ sensitive contrast agent, Gd-DOPTRA has been synthesized and characterized. The agent shows approximately 100% relaxivity enhancement upon addition of Ca2+. The agent is selective and sensitive to Ca2+ also in the presence of Mg2+ and Zn2+. The relaxivity studies carried out in physiological fluids prove the prospects of the agent for in vivo measurements.

Agreement of histopathological findings of uterine curettage and hysterectomy specimens in women with abnormal uterine bleeding.

PubMed

Moradan, Sanam; Ghorbani, Raheb; Lotfi, Azita

2017-05-01

To examined the diagnostic value of  dilatation and curettage (D and C) in patients with abnormal uterine bleeding (AUB) by conducting a histopathological examination of endometrial tissues by D and C and hysterectomy. Methods: In this retrospective study, the medical records of 163 women who had been hospitalized  in the Obstetrics and Gynecology Ward, Amir-al-Momenin Hospital, Semnan, Iran between 2010 and 2015 for diagnostic curettage due to  AUB and who had undergone hysterectomy were investigated. The patients' characteristics and histopathologic results of curettage and hysterectomy were extracted, and sensitivity and specificity and positive and negative predictive values of curettage were calculated. Results: The mean ± standard deviation age of the patients was 49.8±7.8 years. The sensitivity values of D and C in the diagnosis of endometrial pathologies was 49.1%, specificity 84.5%, positive 60.5%, and negative predictive 77.5%. The sensitivities of D and C in the diagnosis of various endometrial hyperplasia was 62.5%, disordered proliferative endometrium 36.8%, and endometrial cancer 83.3%. Of 6 patients with endometrial polyps on performing hysterectomy, no patient was diagnosed by curettage. Conclusions: Dilatation and curettage has acceptable sensitivity in the diagnosis of endometrial cancer, low sensitivity in the diagnosis of endometrial hyperplasia, and very low sensitivity in the diagnosis of disordered proliferative endometrium and endometrial polyps.

Agreement of histopathological findings of uterine curettage and hysterectomy specimens in women with abnormal uterine bleeding

PubMed Central

Moradan, Sanam; Ghorbani, Raheb; Lotfi, Azita

2017-01-01

Objectives: To examined the diagnostic value of dilatation and curettage (D&C) in patients with abnormal uterine bleeding (AUB) by conducting a histopathological examination of endometrial tissues by D&C and hysterectomy. Methods: In this retrospective study, the medical records of 163 women who had been hospitalized in the Obstetrics and Gynecology Ward, Amir-al-Momenin Hospital, Semnan, Iran between 2010 and 2015 for diagnostic curettage due to AUB and who had undergone hysterectomy were investigated. The patients’ characteristics and histopathologic results of curettage and hysterectomy were extracted, and sensitivity and specificity and positive and negative predictive values of curettage were calculated. Results: The mean ± standard deviation age of the patients was 49.8±7.8 years. The sensitivity values of D&C in the diagnosis of endometrial pathologies was 49.1%, specificity 84.5%, positive 60.5%, and negative predictive 77.5%. The sensitivities of D&C in the diagnosis of various endometrial hyperplasia was 62.5%, disordered proliferative endometrium 36.8%, and endometrial cancer 83.3%. Of 6 patients with endometrial polyps on performing hysterectomy, no patient was diagnosed by curettage. Conclusions: Dilatation and curettage has acceptable sensitivity in the diagnosis of endometrial cancer, low sensitivity in the diagnosis of endometrial hyperplasia, and very low sensitivity in the diagnosis of disordered proliferative endometrium and endometrial polyps. PMID:28439599

A novel method for assessing contrast sensitivity in the beagle dog is sensitive to age and an antioxidant enriched food.

PubMed

de Rivera, Christina; Boutet, Isabelle; Zicker, Steven C; Milgram, Norton W

2005-03-01

Tasks requiring visual discrimination are commonly used in assessment of canine cognitive function. However, little is known about canine visual processing, and virtually nothing is known about the effects of age on canine visual function. This study describes a novel behavioural method developed to assess one aspect of canine visual function, namely contrast sensitivity. Four age groups (young, middle aged, old, and senior) were studied. We also included a group of middle aged to old animals that had been maintained for at least 4 years on a specially formulated food containing a broad spectrum of antioxidants and mitochondrial cofactors. Performance of this group was compared with a group in the same age range maintained on a control diet. In the first phase, all animals were trained to discriminate between two high contrast shapes. In the second phase, contrast was progressively reduced by increasing the luminance of the shapes. Performance decreased as a function of age, but the differences did not achieve statistical significance, possibly because of a small sample size in the young group. All age groups were able to acquire the initial discrimination, although the two older age groups showed slower learning. Errors increased with decreasing contrast with the maximal number of errors for the 1% contrast shape. Also, all animals on the antioxidant diet learned the task and had significantly fewer errors at the high contrast compared with the animals on the control diet. The initial results suggest that contrast sensitivity deteriorates with age in the canine while form perception is largely unaffected by age.

Functional Nanoparticles for Magnetic Resonance Imaging

PubMed Central

Mao, Xinpei; Xu, Jiadi; Cui, Honggang

2016-01-01

Nanoparticle-based magnetic resonance imaging (MRI) contrast agents have received much attention over the past decade. By virtue of a high payload of magnetic moieties, enhanced accumulation at disease sites, and a large surface area for additional modification with targeting ligands, nanoparticle-based contrast agents offer promising new platforms to further enhance the high resolution and sensitivity of MRI for various biomedical applications. T2* superparamagnetic iron oxide nanoparticles (SPIONs) first demonstrated superior improvement on MRI sensitivity. The prevailing SPION attracted growing interest in the development of refined nanoscale versions of MRI contrast agents. Afterwards, T1-based contrast agents were developed, and became the most studied subject in MRI due to the positive contrast they provide that avoids the susceptibility associated with MRI signal reduction. Recently, chemical exchange saturation transfer (CEST) contrast agents have emerged and rapidly gained popularity. The unique aspect of CEST contrast agents is that their contrast can be selectively turned “on” and “off” by radiofrequency (RF) saturation. Their performance can be further enhanced by incorporating a large number of exchangeable protons into well-defined nanostructure. Besides activatable CEST contrast agents, there is growing interest in developing nanoparticle-based activatable MRI contrast agents responsive to stimuli (pH, enzyme, etc.), which improves sensitivity and specificity. In this review, we summarize the recent development of various types of nanoparticle-based MRI contrast agents, and have focused our discussions on the key advantages of introducing nanoparticles in MRI. PMID:27040463

Reducing Spatial Uncertainty Through Attentional Cueing Improves Contrast Sensitivity in Regions of the Visual Field With Glaucomatous Defects

PubMed Central

Phu, Jack; Kalloniatis, Michael; Khuu, Sieu K.

2018-01-01

Purpose Current clinical perimetric test paradigms present stimuli randomly to various locations across the visual field (VF), inherently introducing spatial uncertainty, which reduces contrast sensitivity. In the present study, we determined the extent to which spatial uncertainty affects contrast sensitivity in glaucoma patients by minimizing spatial uncertainty through attentional cueing. Methods Six patients with open-angle glaucoma and six healthy subjects underwent laboratory-based psychophysical testing to measure contrast sensitivity at preselected locations at two eccentricities (9.5° and 17.5°) with two stimulus sizes (Goldmann sizes III and V) under different cueing conditions: 1, 2, 4, or 8 points verbally cued. Method of Constant Stimuli and a single-interval forced-choice procedure were used to generate frequency of seeing (FOS) curves at locations with and without VF defects. Results At locations with VF defects, cueing minimizes spatial uncertainty and improves sensitivity under all conditions. The effect of cueing was maximal when one point was cued, and rapidly diminished when more points were cued (no change to baseline with 8 points cued). The slope of the FOS curve steepened with reduced spatial uncertainty. Locations with normal sensitivity in glaucomatous eyes had similar performance to that of healthy subjects. There was a systematic increase in uncertainty with the depth of VF loss. Conclusions Sensitivity measurements across the VF are negatively affected by spatial uncertainty, which increases with greater VF loss. Minimizing uncertainty can improve sensitivity at locations of deficit. Translational Relevance Current perimetric techniques introduce spatial uncertainty and may therefore underestimate sensitivity in regions of VF loss. PMID:29600116

Quantitation of MRI sensitivity to quasi-monodisperse microbubble contrast agents for spatially resolved manometry.

PubMed

Bencsik, Martin; Al-Rwaili, Amgad; Morris, Robert; Fairhurst, David J; Mundell, Victoria; Cave, Gareth; McKendry, Jonathan; Evans, Stephen

2013-11-01

The direct in-vivo measurement of fluid pressure cannot be achieved with MRI unless it is done with the contribution of a contrast agent. No such contrast agents are currently available commercially, whilst those demonstrated previously only produced qualitative results due to their broad size distribution. Our aim is to quantitate then model the MR sensitivity to the presence of quasi-monodisperse microbubble populations. Lipid stabilised microbubble populations with mean radius 1.2 ± 0.8 μm have been produced by mechanical agitation. Contrast agents with increasing volume fraction of bubbles up to 4% were formed and the contribution the bubbles bring to the relaxation rate was quantitated. A periodic pressure change was also continuously applied to the same contrast agent, until MR signal changes were only due to bubble radius change and not due to a change in bubble density. The MR data compared favourably with the prediction of an improved numerical simulation. An excellent MR sensitivity of 23 % bar(-1) has been demonstrated. This work opens up the possibility of generating microbubble preparations tailored to specific applications with optimised MR sensitivity, in particular MRI based in-vivo manometry. Copyright © 2012 Wiley Periodicals, Inc.

TOPEX/El Niño Watch - Pacific Ocean Conditions are Split: Cold in East, Hot in West, July 27, 1999

NASA Image and Video Library

1999-08-23

The North Pacific Ocean continues to run hot and cold, with abnormally low sea levels and cool waters in the northeastern Pacific contrasting with unusually high sea levels and warm waters in the northwestern Pacific.

Stress--the battle for hearts and minds: links between depression, stress and ischemic heart disease.

PubMed

Korszun, Ania; Frenneaux, Michael P

2006-09-01

Depression and ischemic heart disease (IHD) are strongly related common disorders. Depression itself is an independent cardiac risk factor and is associated with a two- to threefold increase in IHD mortality. Attention has now shifted to identifying the common underlying mechanisms that could make individuals susceptible to both disorders. Abnormalities that have been implicated in this relationship include abnormal platelet activation, decreased baroreceptor sensitivity and endothelial dysfunction. Depression and IHD both have a high association with environmental stress, and depression is characterized by abnormalities of the stress-hormone axis. This review provides a brief overview of some recent developments in our understanding of the pathophysiological links between stress, depression and IHD.

Modification of YAPE keypoint detection algorithm for wide local contrast range images

NASA Astrophysics Data System (ADS)

Lukoyanov, A.; Nikolaev, D.; Konovalenko, I.

2018-04-01

Keypoint detection is an important tool of image analysis, and among many contemporary keypoint detection algorithms YAPE is known for its computational performance, allowing its use in mobile and embedded systems. One of its shortcomings is high sensitivity to local contrast which leads to high detection density in high-contrast areas while missing detections in low-contrast ones. In this work we study the contrast sensitivity of YAPE and propose a modification which compensates for this property on images with wide local contrast range (Yet Another Contrast-Invariant Point Extractor, YACIPE). As a model example, we considered the traffic sign recognition problem, where some signs are well-lighted, whereas others are in shadows and thus have low contrast. We show that the number of traffic signs on the image of which has not been detected any keypoints is 40% less for the proposed modification compared to the original algorithm.

Association between visual impairment and patient-reported visual disability at different stages of cataract surgery.

PubMed

Acosta-Rojas, E Ruthy; Comas, Mercè; Sala, Maria; Castells, Xavier

2006-10-01

To evaluate the association between visual impairment (visual acuity, contrast sensitivity, stereopsis) and patient-reported visual disability at different stages of cataract surgery. A cohort of 104 patients aged 60 years and over with bilateral cataract was assessed preoperatively, after first-eye surgery (monocular pseudophakia) and after second-eye surgery (binocular pseudophakia). Partial correlation coefficients (PCC) and linear regression models were calculated. In patients with bilateral cataracts, visual disability was associated with visual acuity (PCC = -0.30) and, to a lesser extent, with contrast sensitivity (PCC = 0.16) and stereopsis (PCC = -0.09). In monocular and binocular pseudophakia, visual disability was more strongly associated with stereopsis (PCC = -0.26 monocular and -0.51 binocular) and contrast sensitivity (PCC = 0.18 monocular and 0.34 binocular) than with visual acuity (PCC = -0.18 monocular and -0.18 binocular). Visual acuity, contrast sensitivity and stereopsis accounted for between 17% and 42% of variance in visual disability. The association of visual impairment with patient-reported visual disability differed at each stage of cataract surgery. Measuring other forms of visual impairment independently from visual acuity, such as contrast sensitivity or stereopsis, could be important in evaluating both needs and outcomes in cataract surgery. More comprehensive assessment of the impact of cataract on patients should include measurement of both visual impairment and visual disability.

Interactions between chromatic- and luminance-contrast-sensitive stereopsis mechanisms.

PubMed

Simmons, David R; Kingdom, Frederick A A

2002-06-01

It is well known that chromatic information can assist in solving the stereo correspondence problem. It has also been suggested that there are two independent first-order stereopsis mechanisms, one sensitive to chromatic contrast and the other sensitive to luminance contrast (Vision Research 37 (1997) 1271). Could the effect of chromatic information on stereo correspondence be subserved by interactions between these mechanisms? To address this question, disparity thresholds (1/stereoacuity) were measured using 0.5 cpd Gabor patches. The stimuli possessed different relative amounts of chromatic and luminance contrast which could be correlated or anti-correlated between the eyes. Stereoscopic performance with these compound stimuli was compared to that with purely isoluminant and isochromatic stimuli at different contrasts. It was found that anti-correlated chromatic contrast severely disrupted stereopsis with achromatic stimuli and that anti-correlated luminance contrast severely disrupted stereopsis with chromatic stimuli. Less dramatic, but still significant, was the improvement in stereoacuity obtained using correlated colour and luminance contrast. These data are consistent with there being positive and negative interactions between chromatic and achromatic stereopsis mechanisms that take place after the initial encoding of disparity information, but before the extraction of stereoscopic depth. These interactions can be modelled satisfactorily assuming probability summation of depth sign information between independent mechanisms.

Effect of bevacizumab on radiation necrosis of the brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzalez, Javier; Kumar, Ashok J.; Conrad, Charles A.

Purpose: Because blocking vascular endothelial growth factor (VEGF) from reaching leaky capillaries is a logical strategy for the treatment of radiation necrosis, we reasoned that bevacizumab might be an effective treatment of radiation necrosis. Patients and Methods: Fifteen patients with malignant brain tumors were treated with bevacizumab or bevacizumab combination for their tumor on either a 5 mg/kg/2-week or 7.5 mg/kg/3-week schedule. Radiation necrosis was diagnosed in 8 of these patients on the basis of magnetic resonance imaging (MRI) and biopsy. MRI studies were obtained before treatment and at 6-week to 8-week intervals. Results: Of the 8 patients with radiationmore » necrosis, posttreatment MRI performed an average of 8.1 weeks after the start of bevacizumab therapy showed a reduction in all 8 patients in both the MRI fluid-attenuated inversion-recovery (FLAIR) abnormalities and T1-weighted post-Gd-contrast abnormalities. The average area change in the T1-weighted post-Gd-contrast abnormalities was 48% ({+-}22 SD), and the average change in the FLAIR images was 60% ({+-}18 SD). The average reduction in daily dexamethasone requirements was 8.6 mg ({+-}3.6). Conclusion: Bevacizumab, alone and in combination with other agents, can reduce radiation necrosis by decreasing capillary leakage and the associated brain edema. Our findings will need to be confirmed in a randomized trial to determine the optimal duration of treatment.« less

Emulsifier for intravenous cyclosporin inhibits neurite outgrowth, causes deficits in rapid axonal transport and leads to structural abnormalities in differentiating N1E.115 neuroblastoma.

PubMed

Brat, D J; Windebank, A J; Brimijoin, S

1992-05-01

The emulsifier for cyclosporin in clinical i.v. formulations, Cremophor EL, has recently come into question as a possible source of neurotoxic side effects in immunosuppressant therapy. To address this issue we tested Cremophor EL and cyclosporin on an in vitro neuronal model, the differentiating N1E.115 neuroblastoma cell. In terms of effects on elaboration of neurites by these cells, Cremophor accounted for nearly all the neurotoxicity of clinically formulated cyclosporin. At a concentration of 0.005% (v/v), Cremophor EL halved the number of cells that extended neurites after 48 hr in serum-free medium. Average neurite length was also reduced substantially. Inhibition of neurite outgrowth first became apparent 24 hr after exposure to Cremophor EL. Neurites that did grow in the presence of Cremophor were disfigured by a series of regularly spaced, gross dilatations (beads) filled with large (0.2-0.5 microns) lipid vesicles. Abnormalities of rapid axonal transport were documented in the beaded neurites by means of video-enhanced contrast, differential interference-contrast microscopy. Velocity of retrograde transport remained normal, but the velocity of anterograde transport and the total bidirectional flux of organelles were both reduced. It seems likely that the inhibition of neurite outgrowth, the swellings of the neurites and the abnormalities of transport are interrelated phenomena.

3D non-contrast-enhanced ECG-gated MR angiography of the lower extremities with dual-source radiofrequency transmission at 3.0 T: Intraindividual comparison with contrast-enhanced MR angiography in PAOD patients.

PubMed

Rasper, Michael; Wildgruber, Moritz; Settles, Marcus; Eckstein, Hans-Henning; Zimmermann, Alexander; Reeps, Christian; Rummeny, Ernst J; Huber, Armin M

2016-09-01

To compare prospectively image quality and diagnostic confidence of flow-sensitive 3D turbo spin echo (TSE)-based non-contrast-enhanced MR angiography (NE-MRA) at 3.0 T using dual-source radiofrequency (RF) transmission with contrast-enhanced MRA (CE-MRA) in patients with peripheral arterial occlusive disease (PAOD). After consent was obtained, 35 patients (mean age 69.1 ± 10.6 years) with PAOD stage II-IV underwent NE-MRA followed by CE-MRA. Signal-to-noise ratio and contrast-to-noise ratio were calculated. Subjective image quality was independently assessed by two radiologists and stenosis scoring was performed in 875 arterial segments. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for stenosis classification were calculated using CE-MRA as a reference method. Diagnostic agreement with CE-MRA was evaluated with Cohen's kappa statistics. NE-MRA provided high objective and subjective image quality at all levels of the arterial tree. Sensitivity and specificity for the detection of relevant stenosis was 91 % and 89 %, respectively; the NPV was 96 % and the PPV 78 %. There was good concordance between CE-MRA and NE-MRA in stenosis scoring. 3D electrocardiography (ECG)-gated TSE NE-MRA with patient-adaptive dual-source RF transmission at 3.0 T is a promising alternative for PAOD patients with contraindications for gadolinium-based contrast agents. It offers high sensitivity and NPV values in the detection of clinically relevant arterial stenosis. • Flow-sensitive TSE NE-MRA is a promising technique for PAOD evaluation. • Diagnostic accuracy is comparable to contrast-enhanced MRA. • NE-MRA eliminates the risk of NSF in patients with renal insufficiency. • Costs arising from the use of contrast agents can be avoided.

A time-series study of sick building syndrome: chronic, biotoxin-associated illness from exposure to water-damaged buildings.

PubMed

Shoemaker, Ritchie C; House, Dennis E

2005-01-01

The human health risk for chronic illnesses involving multiple body systems following inhalation exposure to the indoor environments of water-damaged buildings (WDBs) has remained poorly characterized and the subject of intense controversy. The current study assessed the hypothesis that exposure to the indoor environments of WDBs with visible microbial colonization was associated with illness. The study used a cross-sectional design with assessments at five time points, and the interventions of cholestyramine (CSM) therapy, exposure avoidance following therapy, and reexposure to the buildings after illness resolution. The methodological approach included oral administration of questionnaires, medical examinations, laboratory analyses, pulmonary function testing, and measurements of visual function. Of the 21 study volunteers, 19 completed assessment at each of the five time points. Data at Time Point 1 indicated multiple symptoms involving at least four organ systems in all study participants, a restrictive respiratory condition in four participants, and abnormally low visual contrast sensitivity (VCS) in 18 participants. Serum leptin levels were abnormally high and alpha melanocyte stimulating hormone (MSH) levels were abnormally low. Assessments at Time Point 2, following 2 weeks of CSM therapy, indicated a highly significant improvement in health status. Improvement was maintained at Time Point 3, which followed exposure avoidance without therapy. Reexposure to the WDBs resulted in illness reacquisition in all participants within 1 to 7 days. Following another round of CSM therapy, assessments at Time Point 5 indicated a highly significant improvement in health status. The group-mean number of symptoms decreased from 14.9+/-0.8 S.E.M. at Time Point 1 to 1.2+/-0.3 S.E.M., and the VCS deficit of approximately 50% at Time Point 1 was fully resolved. Leptin and MSH levels showed statistically significant improvement. The results indicated that CSM was an effective therapeutic agent, that VCS was a sensitive and specific indicator of neurologic function, and that illness involved systemic and hypothalamic processes. Although the results supported the general hypothesis that illness was associated with exposure to the WDBs, this conclusion was tempered by several study limitations. Exposure to specific agents was not demonstrated, study participants were not randomly selected, and double-blinding procedures were not used. Additional human and animal studies are needed to confirm this conclusion, investigate the role of complex mixtures of bacteria, fungi, mycotoxins, endotoxins, and antigens in illness causation, and characterize modes of action. Such data will improve the assessment of human health risk from chronic exposure to WDBs.

Brightness discrimination and contrast sensitivity in chronic glaucoma--a clinical study.

PubMed Central

Teoh, S L; Allan, D; Dutton, G N; Foulds, W S

1990-01-01

The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma. PMID:2186795

Congenital heart disease in adults: Quantitative and qualitative evaluation of IR FLASH and IR SSFP MRA techniques using a blood pool contrast agent in the steady state and comparison to first pass MRA.

PubMed

Febbo, Jennifer A; Galizia, Mauricio S; Murphy, Ian G; Popescu, Andrada; Bi, Xiaoming; Turin, Alexander; Collins, Jeremy; Markl, Michael; Edelman, Robert R; Carr, James C

2015-10-01

To evaluate magnetic resonance angiography sequences during the contrast steady-state (SS-MRA) using inversion recovery (IR) with fast low-angle shot (IR-FLASH) or steady-state free precession (IR-SSFP) read-outs, following the injection of a blood-pool contrast agent, and compare them to first-pass MR angiography (FP-MRA) in adults with congenital heart disease (CHD). Twenty-three adult patients with CHD who underwent both SS-MRA and FP-MRA using a 1.5-T scanner were retrospectively identified. Signal-to-noise and contrast-to-noise ratios were obtained at eight locations within the aorta and pulmonary vessels.. Image quality and the presence of artifacts were subjectively assessed by two radiologists. The presence of pathology was noted and given a confidence score. There was no difference in vessel dimensions among the sequences. IR-SSFP showed better image quality and fewer artifacts than IR-FLASH and FP-MRA. Confidence scores were significantly higher for SS-MRA compared to FP-MRA. Seven cases (30.4%) had findings detected at SS-MRA that were not detected at FP-MRA, and 2 cases (8.7%) had findings detected by IR-SSFP only. SS-MRA of the thoracic vasculature using a blood pool contrast agent offers superior image quality and reveals more abnormalities compared to standard FP-MRA in adults with CHD, and it is best achieved with an IR-SSFP sequence. These sequences could lead to increased detection rates of abnormalities and provide a simpler protocol image acquisition. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Predicting individual contrast sensitivity functions from acuity and letter contrast sensitivity measurements

PubMed Central

Thurman, Steven M.; Davey, Pinakin Gunvant; McCray, Kaydee Lynn; Paronian, Violeta; Seitz, Aaron R.

2016-01-01

Contrast sensitivity (CS) is widely used as a measure of visual function in both basic research and clinical evaluation. There is conflicting evidence on the extent to which measuring the full contrast sensitivity function (CSF) offers more functionally relevant information than a single measurement from an optotype CS test, such as the Pelli–Robson chart. Here we examine the relationship between functional CSF parameters and other measures of visual function, and establish a framework for predicting individual CSFs with effectively a zero-parameter model that shifts a standard-shaped template CSF horizontally and vertically according to independent measurements of high contrast acuity and letter CS, respectively. This method was evaluated for three different CSF tests: a chart test (CSV-1000), a computerized sine-wave test (M&S Sine Test), and a recently developed adaptive test (quick CSF). Subjects were 43 individuals with healthy vision or impairment too mild to be considered low vision (acuity range of −0.3 to 0.34 logMAR). While each test demands a slightly different normative template, results show that individual subject CSFs can be predicted with roughly the same precision as test–retest repeatability, confirming that individuals predominantly differ in terms of peak CS and peak spatial frequency. In fact, these parameters were sufficiently related to empirical measurements of acuity and letter CS to permit accurate estimation of the entire CSF of any individual with a deterministic model (zero free parameters). These results demonstrate that in many cases, measuring the full CSF may provide little additional information beyond letter acuity and contrast sensitivity. PMID:28006065

Segmentation of ribs in digital chest radiographs

NASA Astrophysics Data System (ADS)

Cong, Lin; Guo, Wei; Li, Qiang

2016-03-01

Ribs and clavicles in posterior-anterior (PA) digital chest radiographs often overlap with lung abnormalities such as nodules, and cause missing of these abnormalities, it is therefore necessary to remove or reduce the ribs in chest radiographs. The purpose of this study was to develop a fully automated algorithm to segment ribs within lung area in digital radiography (DR) for removal of the ribs. The rib segmentation algorithm consists of three steps. Firstly, a radiograph was pre-processed for contrast adjustment and noise removal; second, generalized Hough transform was employed to localize the lower boundary of the ribs. In the third step, a novel bilateral dynamic programming algorithm was used to accurately segment the upper and lower boundaries of ribs simultaneously. The width of the ribs and the smoothness of the rib boundaries were incorporated in the cost function of the bilateral dynamic programming for obtaining consistent results for the upper and lower boundaries. Our database consisted of 93 DR images, including, respectively, 23 and 70 images acquired with a DR system from Shanghai United-Imaging Healthcare Co. and from GE Healthcare Co. The rib localization algorithm achieved a sensitivity of 98.2% with 0.1 false positives per image. The accuracy of the detected ribs was further evaluated subjectively in 3 levels: "1", good; "2", acceptable; "3", poor. The percentages of good, acceptable, and poor segmentation results were 91.1%, 7.2%, and 1.7%, respectively. Our algorithm can obtain good segmentation results for ribs in chest radiography and would be useful for rib reduction in our future study.

Brief Daily Periods of Unrestricted Vision Can Prevent Form-Deprivation Amblyopia

PubMed Central

Wensveen, Janice M.; Harwerth, Ronald S.; Hung, Li-Fang; Ramamirtham, Ramkumar; Kee, Chea-su; Smith, Earl L.

2006-01-01

PURPOSE To characterize how the mechanisms that produce unilateral form-deprivation amblyopia integrate the effects of normal and abnormal vision over time, the effects of brief daily periods of unrestricted vision on the spatial vision losses produced by monocular form deprivation were investigated in infant monkeys. METHODS Beginning at 3 weeks of age, unilateral form deprivation was initiated in 18 infant monkeys by securing a diffuser spectacle lens in front of one eye and a clear plano lens in front of the fellow eye. During the treatment period (18 weeks), three infants wore the diffusers continuously. For the other experimental infants, the diffusers were removed daily and replaced with clear, zero-powered lenses for 1 (n = 5), 2 (n = 6), or 4 (n = 4) hours. Four infants reared with binocular zero-powered lenses and four normally reared monkeys provided control data. RESULTS The degree of amblyopia varied significantly with the daily duration of unrestricted vision. Continuous form deprivation caused severe amblyopia. However, 1 hour of unrestricted vision reduced the degree of amblyopia by 65%, 2 hours reduced the deficits by 90%, and 4 hours preserved near-normal spatial contrast sensitivity. CONCLUSIONS The severely amblyogenic effects of form deprivation in infant primates are substantially reduced by relatively short daily periods of unrestricted vision. The manner in which the mechanisms responsible for amblyopia integrate the effects of normal and abnormal vision over time promotes normal visual development and has important implications for the management of human infants with conditions that potentially cause amblyopia. PMID:16723458

Specificity of abnormal brain volume in major depressive disorder: a comparison with borderline personality disorder.

PubMed

Depping, Malte S; Wolf, Nadine D; Vasic, Nenad; Sambataro, Fabio; Thomann, Philipp A; Christian Wolf, R

2015-03-15

Abnormal brain volume has been frequently demonstrated in major depressive disorder (MDD). It is unclear if these findings are specific for MDD since aberrant brain structure is also present in disorders with depressive comorbidity and affective dysregulation, such as borderline personality disorder (BPD). In this transdiagnostic study, we aimed to investigate if regional brain volume loss differentiates between MDD and BPD. Further, we tested for associations between brain volume and clinical variables within and between diagnostic groups. 22 Females with a DSM-IV diagnosis of MDD, 17 females with a DSM-IV diagnosis of BPD and without comorbid posttraumatic stress disorder, and 22 age-matched female healthy controls (HC) were investigated using magnetic resonance imaging. High-resolution structural data were analyzed using voxel-based morphometry. A significant (p<0.05, cluster-corrected) volume decrease of the anterior cingulate cortex (ACC) was found in MDD compared to HC, as opposed to volume decreases of the amygdala in BPD compared to both HC and MDD. Sensitivity and specificity of regional gray matter volume for a diagnosis of MDD were modest to fair. Amygdala volume was related to depressive symptoms across the entire patient sample. Potential limitations of this study include the modest sample size and the heterogeneous psychotropic drug treatment. ACC volume reduction is more pronounced in MDD with an intermediate degree of volume loss in BPD compared to HC. In contrast, amygdala volume loss is more pronounced in BPD compared to MDD, yet amygdala volume is associated with affective symptom expression in both disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

Physiological Exploration of the Long Term Evolutionary Selection against Expression of N-Glycolylneuraminic Acid in the Brain*♦

PubMed Central

Naito-Matsui, Yuko; Davies, Leela R. L.; Takematsu, Hiromu; Chou, Hsun-Hua; Tangvoranuntakul, Pam; Carlin, Aaron F.; Verhagen, Andrea; Heyser, Charles J.; Yoo, Seung-Wan; Choudhury, Biswa; Paton, James C.; Paton, Adrienne W.; Varki, Nissi M.; Schnaar, Ronald L.; Varki, Ajit

2017-01-01

All vertebrate cell surfaces display a dense glycan layer often terminated with sialic acids, which have multiple functions due to their location and diverse modifications. The major sialic acids in most mammalian tissues are N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), the latter being derived from Neu5Ac via addition of one oxygen atom at the sugar nucleotide level by CMP-Neu5Ac hydroxylase (Cmah). Contrasting with other organs that express various ratios of Neu5Ac and Neu5Gc depending on the variable expression of Cmah, Neu5Gc expression in the brain is extremely low in all vertebrates studied to date, suggesting that neural expression is detrimental to animals. However, physiological exploration of the reasons for this long term evolutionary selection has been lacking. To explore the consequences of forced expression of Neu5Gc in the brain, we have established brain-specific Cmah transgenic mice. Such Neu5Gc overexpression in the brain resulted in abnormal locomotor activity, impaired object recognition memory, and abnormal axon myelination. Brain-specific Cmah transgenic mice were also lethally sensitive to a Neu5Gc-preferring bacterial toxin, even though Neu5Gc was overexpressed only in the brain and other organs maintained endogenous Neu5Gc expression, as in wild-type mice. Therefore, the unusually strict evolutionary suppression of Neu5Gc expression in the vertebrate brain may be explained by evasion of negative effects on neural functions and by selection against pathogens. PMID:28049733

Unc-45 Mutations in Caenorhabditis elegans Implicate a CRO1/She4p-like Domain in Myosin Assembly

PubMed Central

Barral, José M.; Bauer, Christopher C.; Ortiz, Irving; Epstein, Henry F.

1998-01-01

The Caenorhabditis elegans unc-45 locus has been proposed to encode a protein machine for myosin assembly. The UNC-45 protein is predicted to contain an NH2-terminal domain with three tetratricopeptide repeat motifs, a unique central region, and a COOH-terminal domain homologous to CRO1 and She4p. CRO1 and She4p are fungal proteins required for the segregation of other molecules in budding, endocytosis, and septation. Three mutations that lead to temperature-sensitive (ts) alleles have been localized to conserved residues within the CRO1/She4p-like domain, and two lethal alleles were found to result from stop codon mutations in the central region that would prevent translation of the COOH-terminal domain. Electron microscopy shows that thick filament accumulation in vivo is decreased by ∼50% in the CB286 ts mutant grown at the restrictive temperature. The thick filaments that assemble have abnormal structure. Immunofluorescence and immunoelectron microscopy show that myosins A and B are scrambled, in contrast to their assembly into distinct regions at the permissive temperature and in wild type. This abnormal structure correlates with the high degree of instability of the filaments in vitro as reflected by their extremely low yields and shortened lengths upon isolation. These results implicate the UNC-45 CRO1/She4p-like region in the assembly of myosin isoforms in C. elegans and suggest a possible common mechanism for the function of this UCS (UNC-45/CRO1/She4p) protein family. PMID:9832550

Ganglion Cell Loss and Age-Related Visual Loss: A Cortical Pooling Analysis

PubMed Central

SCHMIDT, LAURA A.; LY-SCHROEDER, EMILY; SWANSON, WILLIAM H.

2006-01-01

Purpose To evaluate the ability of the cortical pooling model to predict the effects of random, mild ganglion cell loss, we compared the predictions of the model with the age-related loss and variability in achromatic and chromatic contrast sensitivity. Methods The relative sensitivity to small (0.5°) and large (3.0°) stimuli was compared in older (mean = 67 years, n = 27) and younger (mean = 23 years, n = 32) adults. Contrast sensitivity for modulations along the luminance, equiluminant L-cone, and equiluminant S-cone axes was assessed at the fovea and at four peripheral locations (12°). Results When the stimuli were large, threshold measurements obtained from all participants were reliable and well within the range of modulations along the chromatic axes that could be produced by the phosphors of the CRT. For the large stimuli, neither long- nor short-term variability increased as a function of age. Increasing the size of the stimulus did not decrease the magnitude of the age-related losses when the stimulus was chromatic, and visual losses observed with large chromatic stimuli were not different from those obtained with small achromatic stimuli. Moreover, chromatic contrast sensitivity assessments identified significant visual losses in four individuals who were not identified by achromatic contrast sensitivity assessments and only missed identifying one individual with significant losses in achromatic contrast sensitivity. Conclusions The declines in achromatic and chromatic sensitivity as a function of age (0.4 – 0.7 dB per decade) were similar to those obtained in previous studies of achromatic and chromatic perimetry and are consistent with the loss of retinal ganglion cells reported in histologic studies. The results of this study are consistent with the predictions the cortical pooling model makes for both variability and contrast sensitivity. These findings emphasize that selective visual impairments do not necessarily reflect preferential damage to a single ganglion cell class and that it is important to include the influence of higher cortical processing when quantifying the relation between ganglion cells and visual function. PMID:16840870

Effect of text type on near work-induced contrast adaptation in myopic and emmetropic young adults.

PubMed

Yeo, Anna C H; Atchison, David A; Schmid, Katrina L

2013-02-27

Contrast adaptation has been speculated to be an error signal for emmetropization. Myopic children exhibit higher contrast adaptation than emmetropic children. This study aimed to determine whether contrast adaptation varies with the type of text viewed by emmetropic and myopic young adults. Baseline contrast sensitivity was determined in 25 emmetropic and 25 spectacle-corrected myopic young adults for 0.5, 1.2, 2.7, 4.4, and 6.2 cycles per degree (cpd) horizontal sine wave gratings. The adults spent periods looking at a 6.2 cpd high-contrast horizontal grating and reading lines of English and Chinese text (these texts comprised 1.2 cpd row and 6 cpd stroke frequencies). The effects of these near tasks on contrast sensitivity were determined, with decreases in sensitivity indicating contrast adaptation. Contrast adaptation was affected by the near task (F2,672 = 43.0; P < 0.001). Adaptation was greater for the grating task (0.13 ± 0.17 log unit, averaged across all frequencies) than reading tasks, but there was no significant difference between the two reading tasks (English 0.05 ± 0.13 log unit versus Chinese 0.04 ± 0.13 log unit). The myopic group showed significantly greater adaptation (by 0.04, 0.04, and 0.05 log units for English, Chinese, and grating tasks, respectively) than the emmetropic group (F1,48 = 5.0; P = 0.03). In young adults, reading Chinese text induced similar contrast adaptation as reading English text. Myopes exhibited greater contrast adaptation than emmetropes. Contrast adaptation, independent of text type, might be associated with myopia development.

Sensitive and specific detection of classical scrapie prions in the brain of goats by real-time quaking-induced conversion

USDA-ARS?s Scientific Manuscript database

The real-time quaking-induced conversion (RT-QuIC) is a rapid, specific, and sensitive prion seeding activity detection assay that uses recombinant prion protein (rPrPSen) to detect sub-infectious levels of the abnormal isoforms of the prion protein (PrPSc). Although RT-QuIC has been successfully us...

High resolution laboratory grating-based x-ray phase-contrast CT

NASA Astrophysics Data System (ADS)

Viermetz, Manuel P.; Birnbacher, Lorenz J. B.; Fehringer, Andreas; Willner, Marian; Noel, Peter B.; Pfeiffer, Franz; Herzen, Julia

2017-03-01

Grating-based phase-contrast computed tomography (gbPC-CT) is a promising imaging method for imaging of soft tissue contrast without the need of any contrast agent. The focus of this study is the increase in spatial resolution without loss in sensitivity to allow visualization of pathologies comparable to the convincing results obtained at the synchrotron. To improve the effective pixel size a super-resolution reconstruction based on subpixel shifts involving a deconvolution of the image is applied on differential phase-contrast data. In our study we could achieve an effective pixel sizes of 28mm without any drawback in terms of sensitivity or the ability to measure quantitative data.

Preferred retinal locus in macular disease: characteristics and clinical implications.

PubMed

Greenstein, Vivienne C; Santos, Rodrigo A V; Tsang, Stephen H; Smith, R Theodore; Barile, Gaetano R; Seiple, William

2008-10-01

To investigate the location and fixation stability of preferred retinal locations (PRLs) in patients with macular disease, and the relationship among areas of abnormal fundus autofluorescence, the PRL and visual sensitivity. Fifteen patients (15 eyes) were studied. Seven had Stargardt disease, 1 bull's eye maculopathy, 5 age-related macular degeneration, 1 Best disease, and 1 pattern dystrophy. All tested eyes had areas of abnormal fundus autofluorescence. The PRL was evaluated with fundus photography and the Nidek microperimeter. Visual field sensitivity was measured with the Nidek microperimeter. Of the 15 eyes, 4 had foveal and 11 had eccentric fixation. Eccentric PRLs were above the atrophic lesion and their stability did not depend on the degree of eccentricity from the fovea. Visual sensitivity was markedly decreased in locations corresponding to hypofluorescent areas. Sensitivity was not decreased in hyperfluorescent areas corresponding to flecks but was decreased if hyperfluorescence was in the form of dense annuli. Eccentric PRLs were in the superior retina in regions of normal fundus autofluorescence. Fixation stability was not correlated with the degree of eccentricity from the fovea. To assess the outcomes of treatment trials it is important to use methods that relate retinal morphology to visual function.

Abnormal Pain Modulation in Patients with Spatially Distributed Chronic Pain: Fibromyalgia

PubMed Central

Staud, Roland

2009-01-01

Many chronic pain syndromes including fibromyalgia, irritable bowel syndrome, chronic fatigue syndrome, migraine headache, chronic back pain, and complex regional pain syndrome are associated with hypersensitivity to painful stimuli and with reduced endogenous pain inhibition. These findings suggest that modulation of pain-related information may be related to the onset and/or maintenance of chronic pain. Although pain sensitivity and pain inhibition are normally distributed in the general population, they are not useful as reliable predictors of future pain. The combination of heightened pain sensitivity and reduced pain-inhibition, however, appears to predispose individuals to greater risk for increased acute clinical pain (e.g., postoperative pain). It is unknown at this time whether such pain processing abnormalities may also place individuals at increased risk for chronic pain. Psychophysical methods, including heat sensory and pressure pain testing have become increasingly available and can be used for the evaluation of pain sensitivity and pain inhibition. However, long-term prospective studies in the general population are lacking which could yield insight into the role of heightened pain sensitivity and pain disinhibition for the development of chronic pain disorders like fibromyalgia. PMID:19647141

A System for Controlled Presentation of the Arden Contrast Sensitivity Test.

DTIC Science & Technology

1985-12-01

and Woo,1978); I.?glaucoma (Atkin, et al,1979); amblyopia (Hess,1979); retinal degeneration (Woo and Long,1979); multiple sclerosis (Regan, et al...decrease, contrast sensitivity diminishes, and imaging L shifts to an area covering 12 -15 of the peripheral macula . The theoretical threshold grid

Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

NASA Astrophysics Data System (ADS)

Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

2016-02-01

High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis. Electronic supplementary information (ESI) available: Supplementary Fig. S1-S6. See DOI: 10.1039/c5nr08402d