Science.gov

Sample records for late gadolinium-enhanced mri

  1. Emerging concepts for myocardial late gadolinium enhancement MRI.

    PubMed

    Doltra, Adelina; Amundsen, Brage Hoyem; Gebker, Rolf; Fleck, Eckart; Kelle, Sebastian

    2013-08-01

    Late gadolinium enhancement is a useful tool for scar detection, based on differences in the volume of distribution of gadolinium, an extracellular agent. The presence of fibrosis in the myocardium amenable to be detected with late gadolinium enhancement MRI is found not only in ischemic cardiomyopathy, in which it offers information regarding viability and prognosis, but also in a wide variety of non-ischemic cardiomyopathies. In the following review we will discuss the methodological aspects of gadolinium-based imaging, as well as its applications and anticipated future developments. PMID:23909638

  2. Utility of late gadolinium enhancement in pediatric cardiac MRI.

    PubMed

    Etesami, Maryam; Gilkeson, Robert C; Rajiah, Prabhakar

    2016-07-01

    Late gadolinium enhancement (LGE) cardiac magnetic resonance (MR) imaging sequence is increasingly used in the evaluation of pediatric cardiovascular disorders, and although LGE might be a normal feature at the sites of previous surgeries, it is pathologically seen as a result of extracellular space expansion, either from acute cell damage or chronic scarring or fibrosis. LGE is broadly divided into ischemic and non-ischemic patterns. LGE caused by myocardial infarction occurs in a vascular distribution and always involves the subendocardial portion, progressively involving the outer regions in a waveform pattern. Non-ischemic cardiomyopathies can have a mid-myocardial (either linear or patchy), subepicardial or diffuse subendocardial distribution. Idiopathic dilated cardiomyopathy can have a linear mid-myocardial pattern, while hypertrophic cardiomyopathy can have fine, patchy enhancement in hypertrophied and non-hypertrophied segments as well as right ventricular insertion points. Myocarditis and sarcoidosis have a mid-myocardial or subepicardial pattern of LGE. Fabry disease typically affects the basal inferolateral segment while Danon disease typically spares the septum. Pericarditis is characterized by diffuse or focal pericardial thickening and enhancement. Thrombus, the most common non-neoplastic cardiac mass, is characterized by absence of enhancement in all sequences, while neoplastic masses show at least some contrast enhancement, depending on the pathology. Regardless of the etiology, presence of LGE is associated with a poor prognosis. In this review, we describe the technical modifications required for performing LGE cardiac MR sequence in children, review and illustrate the patterns of LGE in children, and discuss their clinical significance. PMID:26718199

  3. Modified Wideband Three-Dimensional Late Gadolinium Enhancement MRI for Patients with Implantable Cardiac Devices

    PubMed Central

    Rashid, Shams; Rapacchi, Stanislas; Shivkumar, Kalyanam; Plotnik, Adam; Finn, J. Paul; Hu, Peng

    2015-01-01

    Purpose To study the effects of cardiac devices on three-dimensional (3D) late gadolinium enhancement (LGE) MRI and to develop a 3D LGE protocol for implantable cardioverter defibrillator (ICD) patients with reduced image artifacts. Theory and Methods The 3D LGE sequence was modified by implementing a wideband inversion pulse, which reduces hyperintensity artifacts, and by increasing bandwidth of the excitation pulse. The modified wideband 3D LGE sequence was tested in phantoms and evaluated in six volunteers and five patients with ICDs. Results Phantom and in vivo studies results demonstrated extended signal void and ripple artifacts in 3D LGE that were associated with ICDs. The reason for these artifacts was slab profile distortion and the subsequent aliasing in the slice-encoding direction. The modified wideband 3D LGE provided significantly reduced ripple artifacts than 3D LGE with wideband inversion only. Comparison of 3D and 2D LGE images demonstrated improved spatial resolution of the heart using 3D LGE. Conclusion Increased bandwidth of the inversion and excitation pulses can significantly reduce image artifacts associated with ICDs. Our modified wideband 3D LGE protocol can be readily used for imaging patients with ICDs given appropriate safety guidelines are followed. PMID:25772155

  4. Atrial Fibrosis Quantified Using Late Gadolinium Enhancement MRI is Associated With Sinus Node Dysfunction Requiring Pacemaker Implant

    PubMed Central

    Akoum, Nazem; Mcgann, Christopher; Vergara, Gaston; Badger, Troy; Ranjan, Ravi; Mahnkopf, Christian; Kholmovski, Eugene; Macleod, Rob; Marrouche, Nassir

    2015-01-01

    Introduction Sinus node dysfunction (SND) commonly manifests with atrial arrhythmias alternating with sinus pauses and sinus bradycardia. The underlying process is thought to be because of atrial fibrosis. We assessed the value of atrial fibrosis, quantified using Late Gadolinium Enhanced-MRI (LGE-MRI), in predicting significant SND requiring pacemaker implant. Methods Three hundred forty-four patients with atrial fibrillation (AF) presenting for catheter ablation underwent LGE-MRI. Left atrial (LA) fibrosis was quantified in all patients and right atrial (RA) fibrosis in 134 patients. All patients underwent catheter ablation with pulmonary vein isolation with posterior wall and septal debulking. Patients were followed prospectively for 329 ± 245 days. Ambulatory monitoring was instituted every 3 months. Symptomatic pauses and bradycardia were treated with pacemaker implantation per published guidelines. Results The average patient age was 65 ± 12 years. The average wall fibrosis was 16.7 ± 11.1% in the LA, and 5.3 ± 6.4% in the RA. RA fibrosis was correlated with LA fibrosis (R2 = 0.26; P < 0.01). Patients were divided into 4 stages of LA fibrosis (Utah I: <5%, Utah II: 5–20%, Utah III: 20–35%, Utah IV: >35%). Twenty-two patients (mean atrial fibrosis, 23.9%) required pacemaker implantation during follow-up. Univariate and multivariate analysis identified LA fibrosis stage (OR, 2.2) as a significant predictor for pacemaker implantation with an area under the curve of 0.704. Conclusions In patients with AF presenting for catheter ablation, LGE-MRI quantification of atrial fibrosis demonstrates preferential LA involvement. Significant atrial fibrosis is associated with clinically significant SND requiring pacemaker implantation. PMID:21806700

  5. Quantification of fibrosis in infarcted swine hearts by ex vivo late gadolinium-enhancement and diffusion-weighted MRI methods

    NASA Astrophysics Data System (ADS)

    Pop, Mihaela; Ghugre, Nilesh R.; Ramanan, Venkat; Morikawa, Lily; Stanisz, Greg; Dick, Alexander J.; Wright, Graham A.

    2013-08-01

    Many have speculated that MRI signal characteristics can be used to identify regions of heterogeneous infarct associated with an arrhythmogenic substrate; however, direct evidence of this relationship is limited. The aim of this study was to demonstrate the remodelling characteristics of fibrosis by means of histology and high-resolution MR imaging. For this purpose, we performed whole-mount histology in heart samples (n = 9) collected from five swine at six weeks post-infarction and compared the extent of fibrosis in the infarcted areas delineated in these histological images with that obtained ex vivo by MRI using late gadolinium-enhancement (LGE) and diffusion-weighted imaging (DWI) methods. All MR images were obtained at a submillimetre resolution (i.e., voxel size of 0.6×0.6×1.2 mm3). Specifically, in the histology images, we differentiated moderate fibrosis (consisting of a mixture of viable and non-viable myocytes, known as border zone, BZ) from severe fibrosis (i.e., the dense scar). Correspondingly, tissue heterogeneities in the MR images were categorized by a Gaussian mixture model into healthy, BZ and scar. Our results showed that (a) both MRI methods were capable of qualitatively distinguishing sharp edges between dense scar and healthy tissue from regions of heterogeneous BZ; (b) the BZ and dense scar areas had intermediate-to-high increased values of signal intensity in the LGE images and of apparent diffusion coefficient in the DWI, respectively. In addition, as demonstrated by the Picrosirius Red and immunohistochemistry stains, the viable bundles in the BZ were clearly separated by thin collagen strands and had reduced expression of Cx43, whereas the core scar was composed of dense fibrosis. A quantitative analysis demonstrated that the comparison between BZ/scar extent in LGE and DWI to the corresponding areas identified in histology yielded very good correlations (i.e., for the scar identified by LGE, R2 was 0.96 compared to R2 = 0.93 for the

  6. Automatic classification of scar tissue in late gadolinium enhancement cardiac MRI for the assessment of left-atrial wall injury after radiofrequency ablation

    NASA Astrophysics Data System (ADS)

    Perry, Daniel; Morris, Alan; Burgon, Nathan; McGann, Christopher; MacLeod, Robert; Cates, Joshua

    2012-03-01

    Radiofrequency ablation is a promising procedure for treating atrial fibrillation (AF) that relies on accurate lesion delivery in the left atrial (LA) wall for success. Late Gadolinium Enhancement MRI (LGE MRI) at three months post-ablation has proven effective for noninvasive assessment of the location and extent of scar formation, which are important factors for predicting patient outcome and planning of redo ablation procedures. We have developed an algorithm for automatic classification in LGE MRI of scar tissue in the LA wall and have evaluated accuracy and consistency compared to manual scar classifications by expert observers. Our approach clusters voxels based on normalized intensity and was chosen through a systematic comparison of the performance of multivariate clustering on many combinations of image texture. Algorithm performance was determined by overlap with ground truth, using multiple overlap measures, and the accuracy of the estimation of the total amount of scar in the LA. Ground truth was determined using the STAPLE algorithm, which produces a probabilistic estimate of the true scar classification from multiple expert manual segmentations. Evaluation of the ground truth data set was based on both inter- and intra-observer agreement, with variation among expert classifiers indicating the difficulty of scar classification for a given a dataset. Our proposed automatic scar classification algorithm performs well for both scar localization and estimation of scar volume: for ground truth datasets considered easy, variability from the ground truth was low; for those considered difficult, variability from ground truth was on par with the variability across experts.

  7. Patterns of late gadolinium enhancement in Duchenne muscular dystrophy carriers

    PubMed Central

    2014-01-01

    Background This study was designed to assess whether cardiovascular magnetic resonance imaging (CMR) in Duchenne muscular dystrophy carriers (DMDc) may index any cell milieu elements of LV dysfunction and whether this cardiac phenotype may be related to genotype. The null hypothesis was that myocardial fibrosis, assessed by late gadolinium enhancement (LGE), might be similarly accounted for in DMDc and gender and age-matched controls. Methods Thirty DMDc patients had CMR and genotyping with 37 gender and age-matched controls. Systolic and diastolic LV function was assessed by 2D-echocardiography. Results Absolute and percent LGE were higher in muscular symptomatic (sym) than asymptomatic (asy) DMDc (1.77 ± 0.27 vs 0.76 ± 0.17 ml; F = 19.6, p < 0.0001 and 1.86 ± 0.26% vs 0.68 ± 0.17%, F = 22.1, p < 0.0001, respectively). There was no correlation between LGE and age. LGE was seen most frequently in segments 5 and 6; segment 5 was involved in all asy-DMDc. Subepicardial LGE predominated, compared to the mid-myocardial one (11 out of 14 DMDc). LGE was absent in the subendocardium. No correlations were seen between genotyping (type of mutation, gene region and protein domain), confined to the exon’s study, and cardiac phenotype. Conclusions A typical myocardial LGE-pattern location (LV segments 5 and 6) was a common finding in DMDc. LGE was more frequently subepicardial plus midmyocardial in sym-DMDc, with normal LV systolic and diastolic function. No genotype-phenothype correlation was found. PMID:25008475

  8. Late Gadolinium Enhancement Among Survivors of Sudden Cardiac Arrest

    PubMed Central

    Neilan, Tomas G.; Farhad, Hoshang; Mayrhofer, Thomas; Shah, Ravi V.; Dodson, John A.; Abbasi, Siddique A.; Danik, Stephan B.; Verdini, Daniel J.; Tokuda, Michifumi; Tedrow, Usha B.; Jerosch-Herold, Michael; Hoffmann, Udo; Ghoshhajra, Brian B.; Stevenson, William G.; Kwong, Raymond Y.

    2016-01-01

    OBJECTIVES The aim of this study was to describe the role of contrast-enhanced cardiac magnetic resonance (CMR) in the workup of patients with aborted sudden cardiac arrest (SCA) and in the prediction of long-term outcomes. BACKGROUND Myocardial fibrosis is a key substrate for SCA, and late gadolinium enhancement (LGE) on a CMR study is a robust technique for imaging of myocardial fibrosis. METHODS We performed a retrospective review of all survivors of SCA who were referred for CMR studies and performed follow-up for the subsequent occurrence of an adverse event (death and appropriate defibrillator therapy). RESULTS After a workup that included a clinical history, electrocardiogram, echocardiography, and coronary angiogram, 137 patients underwent CMR for workup of aborted SCA (66% male; mean age 56 ± 11 years; left ventricular ejection fraction 43 ± 12%). The presenting arrhythmias were ventricular fibrillation (n = 105 [77%]) and ventricular tachycardia (n = 32 [23%]). Overall, LGE was found in 98 patients (71%), with an average extent of 9.9 ± 5% of the left ventricular myocardium. CMR imaging provided a diagnosis or an arrhythmic substrate in 104 patients (76%), including the presence of an infarct-pattern LGE in 60 patients (44%), noninfarct LGE in 21 (15%), active myocarditis in 14 (10%), hypertrophic cardiomyopathy in 3 (2%), sarcoidosis in 3, and arrhythmogenic cardiomyopathy in 3. In a median follow-up of 29 months (range 18 to 43 months), there were 63 events. In a multivariable analysis, the strongest predictors of recurrent events were the presence of LGE (adjusted hazard ratio: 6.7; 95% CI: 2.38 to 18.85; p < 0.001) and the extent of LGE (hazard ratio: 1.15; 95% CI: 1.11 to 1.19; p < 0.001). CONCLUSIONS Among patients with SCA, CMR with contrast identified LGE in 71% and provided a potential arrhythmic substrate in 76%. In follow-up, both the presence and extent of LGE identified a group at markedly increased risk of future adverse events. PMID

  9. High Sensitivity of Late Gadolinium Enhancement for Predicting Microscopic Myocardial Scarring in Biopsied Specimens in Hypertrophic Cardiomyopathy

    PubMed Central

    Konno, Tetsuo; Hayashi, Kenshi; Fujino, Noboru; Nagata, Yoji; Hodatsu, Akihiko; Masuta, Eiichi; Sakata, Kenji; Nakamura, Hiroyuki; Kawashiri, Masa-aki; Yamagishi, Masakazu

    2014-01-01

    Background Myocardial scarring can be assessed by cardiac magnetic resonance imaging with late gadolinium enhancement and by endomyocardial biopsy. However, accuracy of late gadolinium enhancement for predicting microscopic myocardial scarring in biopsied specimens remains unknown in hypertrophic cardiomyopathy. We investigated whether late gadolinium enhancement in the whole heart reflects microscopic myocardial scarring in the small biopsied specimens in hypertrophic cardiomyopathy. Methods and Results Twenty-one consecutive patients with hypertrophic cardiomyopathy who were examined both by cardiac magnetic resonance imaging and by endomyocardial biopsy were retrospectively studied. The right interventricular septum was the target site for endomyocardial biopsy in all patients. Late gadolinium enhancement in the ventricular septum had an excellent sensitivity (100%) with a low specificity (40%) for predicting microscopic myocardial scarring in biopsied specimens. The sensitivity of late gadolinium enhancement in the whole heart remained 100% with a specificity of 27% for predicting microscopic myocardial scarring in biopsied specimens. Quantitative assessments of fibrosis revealed that the extent of late gadolinium enhancement in the whole heart was the only independent variable related to the microscopic collagen fraction in biopsied specimens (β  =  0.59, 95% confident interval: 0.15 – 1.0, p  =  0.012). Conclusions Although there was a compromise in the specificity, the sensitivity of late gadolinium enhancement was excellent for prediction of microscopic myocardial scarring in hypertrophic cardiomyopathy. Moreover, the severity of late gadolinium enhancement was independently associated with the quantitative collagen fraction in biopsied specimens in hypertrophic cardiomyopathy. These findings indicate that late gadolinium enhancement can reflect both the presence and the extent of microscopic myocardial scarring in the small biopsied specimens in

  10. Late gadolinium enhanced cardiovascular magnetic resonance of lamin A/C gene mutation related dilated cardiomyopathy

    PubMed Central

    2011-01-01

    Background The purpose of this study was to identify early features of lamin A/C gene mutation related dilated cardiomyopathy (DCM) with cardiovascular magnetic resonance (CMR). We characterise myocardial and functional findings in carriers of lamin A/C mutation to facilitate the recognition of these patients using this method. We also investigated the connection between myocardial fibrosis and conduction abnormalities. Methods Seventeen lamin A/C mutation carriers underwent CMR. Late gadolinium enhancement (LGE) and cine images were performed to evaluate myocardial fibrosis, regional wall motion, longitudinal myocardial function, global function and volumetry of both ventricles. The location, pattern and extent of enhancement in the left ventricle (LV) myocardium were visually estimated. Results Patients had LV myocardial fibrosis in 88% of cases. Segmental wall motion abnormalities correlated strongly with the degree of enhancement. Myocardial enhancement was associated with conduction abnormalities. Sixty-nine percent of our asymptomatic or mildly symptomatic patients showed mild ventricular dilatation, systolic failure or both in global ventricular analysis. Decreased longitudinal systolic LV function was observed in 53% of patients. Conclusions Cardiac conduction abnormalities, mildly dilated LV and depressed systolic dysfunction are common in DCM caused by a lamin A/C gene mutation. However, other cardiac diseases may produce similar symptoms. CMR is an accurate tool to determine the typical cardiac involvement in lamin A/C cardiomyopathy and may help to initiate early treatment in this malignant familiar form of DCM. PMID:21689390

  11. Clinical significance of late gadolinium enhancement in patients<20 years of age with hypertrophic cardiomyopathy.

    PubMed

    Smith, Brandon M; Dorfman, Adam L; Yu, Sunkyung; Russell, Mark W; Agarwal, Prachi P; Mahani, Maryam Ghadimi; Lu, Jimmy C

    2014-04-01

    Late gadolinium enhancement (LGE) on cardiovascular magnetic resonance imaging is associated with adverse events in adults with hypertrophic cardiomyopathy (HC). However, limited data exist on the extent and clinical significance of LGE in the pediatric population. In 30 patients (aged 14.1±3.2 years) with clinically diagnosed HC who underwent cardiovascular magnetic resonance imaging from 2007 to 2012, segments with hypertrophy and LGE were identified by 2 experienced readers blinded to outcome. Radial, circumferential, and longitudinal strains were evaluated using feature tracking software. The composite outcome was defined as cardiac death, nonsustained ventricular tachycardia, ventricular fibrillation, or appropriate implantable cardioverter-defibrillator discharge. LGE was present in 17 of 30 patients (57%), all in a midmyocardial pattern, with median 3 segments per patient (interquartile range [IQR] 2 to 5). No LGE was detected in patients without phenotypic hypertrophy. Segments with LGE had decreased radial (basal segments 20.7% vs 70.9%, p=0.01), circumferential (basal segments -23.2% vs -29.3%, p=0.04), and longitudinal strains (basal segments -13.8% vs -20.9%, p=0.04). After median follow-up of 26.9 months (IQR 7.5 to 34.3), 7 patients who had an adverse outcome (5 ventricular tachycardia, 1 appropriate implantable cardioverter-defibrillator discharge, and 1 death) had more segments of LGE (median 4, IQR 2 to 7 vs 0, IQR 0 to 2, p=0.01). One patient without LGE had ventricular tachycardia on exercise test. In conclusion, LGE occurs in a similar pattern in pediatric patients with HC as in adults, associated with hypertrophy, decreased myocardial strain, and adverse clinical outcomes. Further longitudinal studies are necessary to evaluate the rate of development of LGE and relation to outcomes in a larger cohort. PMID:24513464

  12. Compressed sensing for rapid late gadolinium enhanced imaging of the left atrium: A preliminary study.

    PubMed

    Kamesh Iyer, Srikant; Tasdizen, Tolga; Burgon, Nathan; Kholmovski, Eugene; Marrouche, Nassir; Adluru, Ganesh; DiBella, Edward

    2016-09-01

    Current late gadolinium enhancement (LGE) imaging of left atrial (LA) scar or fibrosis is relatively slow and requires 5-15min to acquire an undersampled (R=1.7) 3D navigated dataset. The GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) based parallel imaging method is the current clinical standard for accelerating 3D LGE imaging of the LA and permits an acceleration factor ~R=1.7. Two compressed sensing (CS) methods have been developed to achieve higher acceleration factors: a patch based collaborative filtering technique tested with acceleration factor R~3, and a technique that uses a 3D radial stack-of-stars acquisition pattern (R~1.8) with a 3D total variation constraint. The long reconstruction time of these CS methods makes them unwieldy to use, especially the patch based collaborative filtering technique. In addition, the effect of CS techniques on the quantification of percentage of scar/fibrosis is not known. We sought to develop a practical compressed sensing method for imaging the LA at high acceleration factors. In order to develop a clinically viable method with short reconstruction time, a Split Bregman (SB) reconstruction method with 3D total variation (TV) constraints was developed and implemented. The method was tested on 8 atrial fibrillation patients (4 pre-ablation and 4 post-ablation datasets). Blur metric, normalized mean squared error and peak signal to noise ratio were used as metrics to analyze the quality of the reconstructed images, Quantification of the extent of LGE was performed on the undersampled images and compared with the fully sampled images. Quantification of scar from post-ablation datasets and quantification of fibrosis from pre-ablation datasets showed that acceleration factors up to R~3.5 gave good 3D LGE images of the LA wall, using a 3D TV constraint and constrained SB methods. This corresponds to reducing the scan time by half, compared to currently used GRAPPA methods. Reconstruction of 3D LGE images

  13. Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis

    PubMed Central

    Fontana, Marianna; Pica, Silvia; Reant, Patricia; Abdel-Gadir, Amna; Treibel, Thomas A.; Banypersad, Sanjay M.; Maestrini, Viviana; Barcella, William; Rosmini, Stefania; Bulluck, Heerajnarain; Sayed, Rabya H.; Patel, Ketna; Mamhood, Shameem; Bucciarelli-Ducci, Chiara; Whelan, Carol J.; Herrey, Anna S.; Lachmann, Helen J.; Wechalekar, Ashutosh D.; Manisty, Charlotte H.; Schelbert, Eric B.; Kellman, Peter; Gillmore, Julian D.; Hawkins, Philip N.

    2015-01-01

    Background— The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. Methods and Results— Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1–13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E′, and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3–13.1; P<0.05). Conclusions— There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after

  14. MRI-based Kidney Volume Measurements in ADPKD: Reliability and Effect of Gadolinium Enhancement

    PubMed Central

    Bae, Kyongtae T.; Tao, Cheng; Zhu, Fang; Bost, James E.; Chapman, Arlene B.; Grantham, Jared J.; Torres, Vicente E.; Guay-Woodford, Lisa M.; Meyers, Catherine M.; Bennett, William M.

    2009-01-01

    Background and objectives: To evaluate the inter- and intrareader reliability and the effect of gadolinium enhancement on kidney volume measurements obtained from pre- and postgadolinium T1 MR images in patients with autosomal dominant polycystic kidney disease (ADPKD). Design, setting, participants, & measurements: Twenty subjects were randomly selected with approximately equal frequency from three kidney-size groups. Pre- and postgadolinium 3D T1 (pre-T1, post-T1) MR images were obtained. The stereology method was applied to segment and measure kidney volumes. The measurement process was repeated at two-wk intervals by two radiologists. Reliability was assessed with correlation coefficients. Intra- and inter-reader bias and measure differences were assessed with paired T-tests. The size effect on the pre- and post-T1 measurements was evaluated with one-way ANOVA. Results: The intra- and inter-reader reliability was extremely high in all measurements. No systematic intrareader bias but a small inter-reader bias for the post-T1 measurements was observed. All kidney volumes measured on the pre- and post-T1 images were highly correlated with each other for both readers. The post-T1 volumes were significantly higher than pre-T1 volumes. While the post-pre volume differences were relatively constant across the three kidney-size groups, the post-pre percent volume differences were significantly smaller as the size of the kidney increased. Conclusions: Kidney volume measurements can be made with minimum intra- and inter-reader variability on both pre- and post-T1 MR images. Kidney volumes measured on the pre-T1 were smaller than those on post-T1, and percent differences between pre-T1 and post-T1 kidney volumes decreased with increasing kidney size. PMID:19339416

  15. High CD6 and low chemokine receptor expression on peripheral blood lymphocytes correlates with MRI gadolinium enhancement in MS.

    PubMed

    Jurewicz, Anna; Zaleski, Krzysztof; Domowicz, Malgorzata; Selmaj, Krzysztof

    2014-11-15

    Correlation between gadolinium-enhancing [Gd(+)] lesions on MRI and expression of CD6 molecules and a group of chemokine receptors on peripheral blood (PB) and cerebrospinal fluid (CSF) immune cells was measured in multiple sclerosis (MS) patients. Twenty remitting-relapsing MS patients with (n=10) and without (n=10) Gd(+) lesions entered the study. mRNA and surface expression of CD6 and CCR1, CCR2, CCR3 and CCR5 was measured by immunostaining and flow cytometry. Expression of mRNA and surface staining for CD6 in PB T lymphocytes was increased in Gd(+) compared to Gd(-) patients (p<0.01; p<0.05, respectively). CD6 mRNA correlated with the number and size of Gd(+) lesions (r=0.67, and r=0.65 respectively). mRNA and surface expression for CCR1, CCR2, and CCR3 in PB cells was lower in Gd(+) compared to Gd(-) MS patients (p<0.05, p<0.05). The frequency of cells co-expressing CD6 with CCR1 and CCR5 was low in PB T lymphocytes and high in CSF (p<0.05, p<0.05). These results suggest that Gd(+) correlates with increased expression of CD6 and decreased expression of chemokine receptors on PB T lymphocytes. Co-expression of CD6 with CCR1 and CCR5 predisposes cells for transmigration into CSF. PMID:25242631

  16. Quantitative assessment of intervertebral disc glycosaminoglycan distribution by gadolinium-enhanced MRI in orthopedic patients.

    PubMed

    Vaga, Stefania; Raimondi, Manuela Teresa; Caiani, Enrico Gianluca; Costa, Francesco; Giordano, Carmen; Perona, Franco; Zerbi, Alberto; Fornari, Maurizio

    2008-01-01

    Our hypothesis was that the enhanced MRI of cartilage (dGEMRIC) imaging protocol could be used in patients to quantify the sulfated glycosaminoglycan (sGAG) in intervertebral discs (IVD). To test this hypothesis, 23 patients with degenerative disc pathology scheduled for surgery were studied by a specific dGEMRIC protocol: each patient underwent two MRI scans, before and 3.5 hr after Gd(DTPA)2-injection of a nonconventional dose of 40 mL. Then, T(1PRE-ENH) and T(1POST-ENH) parametric images of the disc were obtained, from which a new index DeltaT(1) of the molecular status of the IVD was computed (T(1PRE-ENH) - T(1POST-ENH)). A total of 31 tissue samples (one or two from each patient) obtained at herniectomy were collected and biochemically analyzed for sGAG content and used as the gold standard for comparison. DeltaT(1) values in correspondence to degenerated sectors were higher (158 +/- 36 ms) compared to normal sectors (80 +/- 13 ms). Linear regression analysis between MRI-derived and biochemistry-derived measurements resulted in a significant correlation (r = 0.73, P < 0.0001). The DeltaT(1) parametric images, calculated using the modified dGEMRIC technique, provided noninvasive quantitative information about sGAG content within discal tissue in vivo, which resulted in agreement with biochemical analysis. The application of this new MRI method could provide diagnostic information for standard treatment of lumbar discopathy and for innovative therapies of regenerative medicine. PMID:18050346

  17. Early recurrence of atrial fibrillation after catheter ablation with left atrial fibrosis identified at cardiac magnetic resonance by late gadolinium enhancement.

    PubMed

    Totaro, Antonio; Casavecchia, Graziapia; Gravina, Matteo; Ieva, Riccardo; Santoro, Francesco; Grimaldi, Massimo; Pellegrino, Pier Luigi; Macarini, Luca; Di Biase, Matteo; Brunetti, Natale Daniele

    2016-08-01

    In patients with atrial fibrillation (AF), extensive atrial tissue fibrosis identified by delayed enhancement magnetic resonance imaging has been associated with early recurrence of AF after catheter ablation. We present a case of a patient with extensive atrial fibrosis and AF recurrence.The study of late gadolinium enhancement with cardiac magnetic resonance imaging in patients with AF could be a valuable noninvasive tool for the selection of patients suitable for successful catheter ablation. PMID:26826170

  18. Late gadolinium enhancement in cardiac amyloidosis: attributable both to interstitial amyloid deposition and subendocardial fibrosis caused by ischemia.

    PubMed

    Hashimura, Hiromi; Ishibashi-Ueda, Hatsue; Yonemoto, Yumiko; Ohta-Ogo, Keiko; Matsuyama, Taka-Aki; Ikeda, Yoshihiko; Morita, Yoshiaki; Yamada, Naoaki; Yasui, Hiroki; Naito, Hiroaki

    2016-06-01

    Gadolinium contrast agents used for late gadolinium enhancement (LGE) distribute in the extracellular space. Global diffuse myocardial LGE pronounced in the subendocardial layers is common in cardiac amyloidosis. However, the pathophysiological basis of these findings has not been sufficiently explained. A 64-year-old man was admitted to our hospital with leg edema and nocturnal dyspnea. Bence Jones protein was positive in the urine, and an endomyocardial and skin biopsy showed light-chain (AL) amyloidosis. He died of ventricular fibrillation 3 months later. 9 days before death, the patient was examined by cardiac magnetic resonance (CMR) imaging on a 3-T system. We acquired LGE data at 2, 5, 10, and 20 min after the injection of gadolinium contrast agents, with a fixed inversion time of 350 ms. Myocardial LGE developed sequentially. The myocardium was diffusely enhanced at 2 min, except for the subendocardium, but LGE had extended to almost the entire left ventricle at 5 min and predominantly localized to the subendocardial region at 10 and 20 min. An autopsy revealed massive and diffused amyloid deposits in perimyocytes throughout the myocardium. Old and recent ischemic findings, such as replacement fibrosis and coagulative myocyte necrosis, were evident in the subendocardium. In the intramural coronary arteries, mild amyloid deposits were present within the subepicardial to the mid layer of the left ventricle, but no stenotic lesions were evident. However, capillaries were obstructed by amyloid deposits in the subendocardium. In conclusion, the late phase of dynamic LGE (at 10 and 20 min) visualized in the subendocardium corresponded to the interstitial amyloid deposition and subendocardial fibrosis caused by ischemia in our patient. PMID:25794983

  19. Characteristics and clinical relevance of late gadolinium enhancement in cardiac magnetic resonance in patients with systemic sclerosis.

    PubMed

    Sano, Makoto; Satoh, Hiroshi; Suwa, Kenichiro; Nobuhara, Mamoru; Saitoh, Takeji; Saotome, Masao; Urushida, Tsuyoshi; Katoh, Hideki; Shimoyama, Kumiko; Suzuki, Daisuke; Ogawa, Noriyoshi; Takehara, Yasuo; Sakahara, Harumi; Hayashi, Hideharu

    2015-11-01

    Cardiac involvement in systemic sclerosis (SSc) is considerably frequent in autopsy, but the early identification is clinically difficult. Recent advantages in cardiac magnetic resonance (CMR) enabled to detect myocardial fibrotic scar as late gadolinium enhancement (LGE). We aimed to examine the prevalence and distribution of LGE in patients with SSc, and associate them with clinical features, electrocardiographic abnormalities and cardiac function. Forty patients with SSc (58 ± 14 years-old, 35 females, limited/diffuse 25/15, disease duration 106 ± 113 months) underwent serological tests, 12-lead electrocardiogram (ECG) and CMR. Seven patients (17.5 %) showed LGE in 26 segments of left ventricle (LV). LGE distributed mainly in the basal to mid inter-ventricular septum and the right ventricular (RV) insertion points, but involved all the myocardial regions. More patients with LGE showed NYHA functional class II and more (71 vs. 21 %, p < 0.05), bundle branch blocks (57 vs. 6 %, p < 0.05), LV ejection fraction (LVEF) < 50 % (72 vs. 6 %, p < 0.01), LV asynergy (43 vs. 0 %, p < 0.01) and RVEF < 40 % (100 vs. 39 %, p < 0.01). There was no difference in disease duration, disease types, or prevalence of positive autoimmune antibodies or high serum NT-proBNP level (>125 pg/ml). When cardiac involvement of SSc was defined as low LVEF, ECG abnormalities or high NT-proBNP, the sensitivity, specificity positive and negative predictive values of LGE were 36, 92, 71 and 72 %, respectively. We could clarify the prevalence and distribution of LGE in Japanese patients with SSc. The presence of LGE was associated with cardiac symptom, conduction disturbance and impaired LV/RV contraction. PMID:24996373

  20. Significance of Late Gadolinium Enhancement at Right Ventricular Attachment to Ventricular Septum in Patients With Hypertrophic Cardiomyopathy.

    PubMed

    Chan, Raymond H; Maron, Barry J; Olivotto, Iacopo; Assenza, Gabriele E; Haas, Tammy S; Lesser, John R; Gruner, Christiane; Crean, Andrew M; Rakowski, Harry; Rowin, Ethan; Udelson, James; Lombardi, Massimo; Tomberli, Benedetta; Spirito, Paolo; Formisano, Francesco; Marra, Martina P; Biagini, Elena; Autore, Camillo; Manning, Warren J; Appelbaum, Evan; Roberts, William C; Basso, Cristina; Maron, Martin S

    2015-08-01

    Cardiovascular magnetic resonance (CMR) with extensive late gadolinium enhancement (LGE) is a novel marker for increased risk for sudden death (SD) in patients with hypertrophic cardiomyopathy (HC). Small focal areas of LGE confined to the region of right ventricular (RV) insertion to ventricular septum (VS) have emerged as a frequent and highly visible CMR imaging pattern of uncertain significance. The aim of this study was to evaluate the prognostic significance of LGE confined to the RV insertion area in patients with HC. CMR was performed in 1,293 consecutive patients with HC from 7 HC centers, followed for 3.4 ± 1.7 years. Of 1,293 patients (47 ± 14 years), 134 (10%) had LGE present only in the anterior and/or inferior areas of the RV insertion to VS, occupying 3.7 ± 2.9% of left ventricular myocardium. Neither the presence nor extent of LGE in these isolated areas was a predictor of adverse HC-related risk, including SD (adjusted hazard ratio 0.82, 95% confidence interval 0.45 to 1.50, p = 0.53; adjusted hazard ratio 1.16/10% increase in LGE, 95% confidence interval 0.29 to 4.65, p = 0.83, respectively). Histopathology in 20 HC hearts show the insertion areas of RV attachment to be composed of a greatly expanded extracellular space characterized predominantly by interstitial-type fibrosis and interspersed disorganized myocyte patterns and architecture. In conclusion, LGE confined to the insertion areas of RV to VS was associated with low risk of adverse events (including SD). Gadolinium pooling in this region of the left ventricle does not reflect myocyte death and repair with replacement fibrosis or scarring. PMID:26026863

  1. Nocturnal Blood Pressure Pattern Affects Left Ventricular Remodeling and Late Gadolinium Enhancement in Patients with Hypertension and Left Ventricular Hypertrophy

    PubMed Central

    Yokota, Hajime; Imai, Yasuko; Tsuboko, Yusuke; Tokumaru, Aya M.; Fujimoto, Hajime; Harada, Kazumasa

    2013-01-01

    Background Left ventricular hypertrophy (LVH) is an independent predictor of cardiac mortality, regardless of its etiology. Previous studies have shown that high nocturnal blood pressure (BP) affects LV geometry in hypertensive patients. It has been suggested that continuous pressure overload affects the development of LVH, but it is unknown whether persistent pressure influences myocardial fibrosis or whether the etiology of LVH is associated with myocardial fibrosis. Comprehensive cardiac magnetic resonance (CMR) including the late gadolinium enhancement (LGE) technique can evaluate both the severity of changes in LV geometry and myocardial fibrosis. We tested the hypothesis that the nocturnal non-dipper BP pattern causes LV remodeling and fibrosis in patients with hypertension and LVH. Methods Forty-seven hypertensive patients with LVH evaluated by echocardiography (29 men, age 73.0±10.4 years) were examined by comprehensive CMR and 24-h ambulatory blood pressure monitoring (ABPM). Results and Conclusions Among the 47 patients, twenty-four had nocturnal non-dipper BP patterns. Patients with nocturnal non-dipper BP patterns had larger LV masses and scar volumes independent of etiologies than those in patients with dipper BP patterns (p = 0.035 and p = 0.015, respectively). There was no significant difference in mean 24-h systolic BP between patients with and without nocturnal dipper BP patterns (p = 0.367). Among hypertensive patients with LVH, the nocturnal non-dipper blood pressure pattern is associated with both LV remodeling and myocardial fibrosis independent of LVH etiology. PMID:23840777

  2. Evaluation of state-of-the-art segmentation algorithms for left ventricle infarct from late Gadolinium enhancement MR images.

    PubMed

    Karim, Rashed; Bhagirath, Pranav; Claus, Piet; Housden, R James; Chen, Zhong; Karimaghaloo, Zahra; Sohn, Hyon-Mok; Lara Rodríguez, Laura; Vera, Sergio; Albà, Xènia; Hennemuth, Anja; Peitgen, Heinz-Otto; Arbel, Tal; Gonzàlez Ballester, Miguel A; Frangi, Alejandro F; Götte, Marco; Razavi, Reza; Schaeffter, Tobias; Rhode, Kawal

    2016-05-01

    Studies have demonstrated the feasibility of late Gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging for guiding the management of patients with sequelae to myocardial infarction, such as ventricular tachycardia and heart failure. Clinical implementation of these developments necessitates a reproducible and reliable segmentation of the infarcted regions. It is challenging to compare new algorithms for infarct segmentation in the left ventricle (LV) with existing algorithms. Benchmarking datasets with evaluation strategies are much needed to facilitate comparison. This manuscript presents a benchmarking evaluation framework for future algorithms that segment infarct from LGE CMR of the LV. The image database consists of 30 LGE CMR images of both humans and pigs that were acquired from two separate imaging centres. A consensus ground truth was obtained for all data using maximum likelihood estimation. Six widely-used fixed-thresholding methods and five recently developed algorithms are tested on the benchmarking framework. Results demonstrate that the algorithms have better overlap with the consensus ground truth than most of the n-SD fixed-thresholding methods, with the exception of the Full-Width-at-Half-Maximum (FWHM) fixed-thresholding method. Some of the pitfalls of fixed thresholding methods are demonstrated in this work. The benchmarking evaluation framework, which is a contribution of this work, can be used to test and benchmark future algorithms that detect and quantify infarct in LGE CMR images of the LV. The datasets, ground truth and evaluation code have been made publicly available through the website: https://www.cardiacatlas.org/web/guest/challenges. PMID:26891066

  3. Quantitative assessment of myocardial fibrosis in an age-related rat model by ex vivo late gadolinium enhancement magnetic resonance imaging with histopathological correlation.

    PubMed

    Beliveau, Pascale; Cheriet, Farida; Anderson, Stasia A; Taylor, Joni L; Arai, Andrew E; Hsu, Li-Yueh

    2015-10-01

    Late gadolinium enhanced (LGE) cardiac magnetic resonance (CMR) imaging can detect the presence of myocardial infarction from ischemic cardiomyopathies (ICM). However, it is more challenging to detect diffuse myocardial fibrosis from non-ischemic cardiomyopathy (NICM) with this technique due to more subtle and heterogeneous enhancement of the myocardium. This study investigates whether high-resolution LGE CMR can detect age-related myocardial fibrosis using quantitative texture analysis with histological validation. LGE CMR of twenty-four rat hearts (twelve 6-week-old and twelve 2-year-old) was performed using a 7T MRI scanner. Picrosirius red was used as the histopathology reference for collagen staining. Fibrosis in the myocardium was quantified with standard deviation (SD) threshold methods from the LGE CMR images and 3D contrast texture maps that were computed from gray level co-occurrence matrix of the CMR images. There was a significant increase of collagen fibers in the aged compared to the young rat histology slices (2.60±0.27 %LV vs. 1.24±0.29 %LV, p<0.01). Both LGE CMR and texture images showed a significant increase of myocardial fibrosis in the elderly compared to the young rats. Fibrosis in the LGE CMR images correlated strongly with histology with the 3 SD threshold (r=0.84, y=0.99x+0.00). Similarly, fibrosis in the contrast texture maps correlated with the histology using the 4 SD threshold (r=0.89, y=1.01x+0.00). High resolution ex-vivo LGE CMR can detect the presence of diffuse fibrosis that naturally developed in elderly rat hearts. Our results suggest that texture analysis may improve the assessment of myocardial fibrosis in LGE CMR images. PMID:26313531

  4. Severe Left Ventricular Hypertrophy, Small Pericardial Effusion, and Diffuse Late Gadolinium Enhancement by Cardiac Magnetic Resonance Suspecting Cardiac Amyloidosis: Endomyocardial Biopsy Reveals an Unexpected Diagnosis

    PubMed Central

    Hofmann, Nina P.; Giusca, Sorin; Klingel, Karin; Nunninger, Peter; Korosoglou, Grigorios

    2016-01-01

    Left ventricular (LV) hypertrophy can be related to a multitude of cardiac disorders, such as hypertrophic cardiomyopathy (HCM), cardiac amyloidosis, and hypertensive heart disease. Although the presence of LV hypertrophy is generally associated with poorer cardiac outcomes, the early differentiation between these pathologies is crucial due to the presence of specific treatment options. The diagnostic process with LV hypertrophy requires the integration of clinical evaluation, electrocardiography (ECG), echocardiography, biochemical markers, and if required CMR and endomyocardial biopsy in order to reach the correct diagnosis. Here, we present a case of a patient with severe LV hypertrophy (septal wall thickness of 23 mm, LV mass of 264 g, and LV mass index of 147 g/m2), severely impaired longitudinal function, and preserved radial contractility (ejection fraction = 55%), accompanied by small pericardial effusion and diffuse late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR). Due to the imaging findings, an infiltrative cardiomyopathy, such as cardiac amyloidosis, was suspected. However, amyloid accumulation was excluded by endomyocardial biopsy, which revealed the presence of diffuse myocardial fibrosis in an advanced hypertensive heart disease. PMID:27247807

  5. Incremental prognostic value of the SYNTAX score to late gadolinium-enhanced magnetic resonance images for patients with stable coronary artery disease.

    PubMed

    Kato, Shingo; Saito, Naka; Kirigaya, Hidekuni; Gyotoku, Daiki; Iinuma, Naoki; Kusakawa, Yuka; Iguchi, Kohei; Nakachi, Tatsuya; Fukui, Kazuki; Futaki, Masaaki; Iwasawa, Tae; Taguri, Masataka; Kimura, Kazuo; Umemura, Satoshi

    2016-06-01

    The prognostic significance of the SYNTAX (Synergy between PCI with Taxus and cardiac surgery) score has recently been demonstrated in patients with stable multivessel or left main coronary artery disease (CAD). The present study determines whether adding the SYNTAX score to Framingham risk score (FRS), left ventricular ejection fraction (LVEF) and presence of myocardial infarction (MI) by late gadolinium enhancement (LGE) magnetic resonance imaging can improve the risk stratification in patients with stable CAD. We calculated the SYNTAX score in 161 patients with stable CAD (mean age: 66 ± 10 years old). During a mean follow-up of 2.3 years, 56 (35 %) of 161 patients developed cardiovascular events defined as cardiovascular death, non-fatal MI, cerebral infarction, unstable angina pectoris, hospitalization due to heart failure and revascularization. Multivariate Cox regression analysis selected triglycerides [hazard ratio (HR): 1.005 (95 % confidence interval (CI): 1.001-1.008), p < 0.008], presence of LGE [HR: 6.329 (95 % CI: 2.662-15.05), p < 0.001] and the SYNTAX score [HR: 1.085 (95 % CI: 1.044-1.127), p < 0.001] as risk factors for future cardiovascular events. Adding the SYNTAX score to FRS, EF and LGE significantly improved the net reclassification index (NRI) [40.4 % (95 % CI: 18.1-54.8 %), p < 0.05] with an increase in C-statistics of 0.089 (from 0.707 to 0.796). An increase in C-statistics and significant improvement of NRI showed that adding the SYNTAX score to the FRS, LVEF and LGE incrementally improved risk stratification in patient with stable CAD. PMID:25904244

  6. Assessment of Lumbar Intervertebral Disc Glycosaminoglycan Content by Gadolinium-Enhanced MRI before and after 21-Days of Head-Down-Tilt Bedrest

    PubMed Central

    Koy, Timmo; Zange, Jochen; Rittweger, Jörn; Pohle-Fröhlich, Regina; Hackenbroch, Matthias; Eysel, Peer; Ganse, Bergita

    2014-01-01

    During spaceflight, it has been shown that intervertebral discs (IVDs) increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6° head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI) scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) protocol before and after bedrest. The outcome measures were T1 and ΔT1. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T1-values of both scans (ΔT1) were computed. ΔT1 is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ΔT1 (p<0.001) after bedrest in all IVDs, and in all areas of the IVDs. The ΔT1-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ΔT1-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T1 before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ΔT1 may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems contradictory to

  7. In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC)

    PubMed Central

    2014-01-01

    Background Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-. Methods The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3 mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1 = 1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180 minutes after injection, and the change in relaxation rate (ΔR1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation. Results The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ΔR1 were similar for double and triple doses of the contrast agent. ΔR1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ΔR1 increased until 90-180 minutes in both the cartilage and the meniscus (p < 0.05), and was lower in the medial than in the lateral meniscus at all time points (p < 0.05). A faster increase in ΔR1 was observed in the vascularized peripheral region of the posterior medial meniscus, than in the avascular central

  8. Dynamic Changes of Edema and Late Gadolinium Enhancement after Acute Myocardial Infarction and Their Relationship to Functional Recovery and Salvage Index

    PubMed Central

    Dall’Armellina, Erica; Karia, Nina; Lindsay, Alistair C.; Karamitsos, Theodoros D.; Ferreira, Vanessa; Robson, Matthew D; Kellman, Peter; Francis, Jane; Forfar, Colin; Prendergast, Bernard; Banning, Adrian P; Channon, Keith M; Kharbanda, Rajesh K; Neubauer, Stefan; Choudhury, Robin P

    2011-01-01

    Background Changes in the myocardium in acute ischemia are dynamic and complex and the characteristics of myocardial tissue on cardiovascular magnetic resonance (CMR) in the acute setting are not fully defined. We investigated changes in edema and late gadolinium enhancement (LGE) with serial imaging early after acute MI, relating these to global and segmental myocardial function at 6 months. Methods and Results CMR scans were performed on 30 patients with ST elevation MI (STEMI) treated by primary PCI at each of 4 time points: 12-48 hours (24H); 5-7 days (1W); 14-17 days (2W); and 6 months (6M). All patients showed edema at 24H. The mean volume of edema (% LV) was 37 ± 16 at 24H and 39 ± 17 at 1W with a reduction to 24 ± 13 (P < 0.01) by 2W. Myocardial segments with edema also had increased signal on LGE at 24H (kappa = 0.77; P < 0.001). The volume of LGE decreased significantly between 24H and 6M (27 ± 15 % vs. 22 ± 12 %; P = 0.002). Of segments showing LGE at 24H, 50% showed resolution by six months. In segments with such a reduction in LGE, 65% also showed improved wall motion (P < 0.0001). The area of LGE measured at 6M correlated more strongly with troponin at 48h (r = 0.9; P < 0.01) than LGE at 24H (r = 0.7). The difference in LGE between 24H and 6M had profound effects on the calculation of salvage index (26 ± 21 % at 24H vs. 42 ± 23 % at 6M; P = 0.02). Conclusions Myocardial edema is maximal and constant over the first week post MI, providing a stable window for the retrospective evaluation of area at risk. By contrast, myocardial areas with high signal intensity in LGE images recede over time with corresponding recovery of function, indicating that acutely detected LGE does not necessarily equate with irreversible injury and may severely underestimate salvaged myocardium. PMID:21447711

  9. MultiContrast Delayed Enhancement (MCODE) improves detection of subendocardial myocardial infarction by late gadolinium enhancement cardiovascular magnetic resonance: a clinical validation study

    PubMed Central

    2012-01-01

    Background Myocardial infarction (MI) documented by late gadolinium enhancement (LGE) has clinical and prognostic importance, but its detection is sometimes compromised by poor contrast between blood and MI. MultiContrast Delayed Enhancement (MCODE) is a technique that helps discriminate subendocardial MI from blood pool by simultaneously providing a T2-weighted image with a PSIR (phase sensitive inversion recovery) LGE image. In this clinical validation study, our goal was to prospectively compare standard LGE imaging to MCODE in the detection of MI. Methods Imaging was performed on a 1.5 T scanner on patients referred for CMR including a LGE study. Prospective comparisons between MCODE and standard PSIR LGE imaging were done by targeted, repeat imaging of slice locations. Clinical data were used to determine MI status. Images at each of multiple time points were read on separate days and categorized as to whether or not MI was present and whether an infarction was transmural or subendocardial. The extent of infarction was scored on a sector-by-sector basis. Results Seventy-three patients were imaged with the specified protocol. The majority were referred for vasodilator perfusion exams and viability assessment (37 ischemia assessment, 12 acute MI, 10 chronic MI, 12 other diagnoses). Forty-six patients had a final diagnosis of MI (30 subendocardial and 16 transmural). MCODE had similar specificity compared to LGE at all time points but demonstrated better sensitivity compared to LGE performed early and immediately before and after the MCODE (p = 0.008 and 0.02 respectively). Conventional LGE only missed cases of subendocardial MI. Both LGE and MCODE identified all transmural MI. Based on clinical determination of MI, MCODE had three false positive MI’s; LGE had two false positive MI’s including two of the three MCODE false positives. On a per sector basis, MCODE identified more infarcted sectors compared to LGE performed immediately prior to MCODE (p < 0

  10. Prevalence, Patterns, and Clinical Predictors of Left Ventricular Late Gadolinium Enhancement in Patients Undergoing Cardiac Magnetic Resonance Prior to Pulmonary Vein Antral Isolation for Atrial Fibrillation

    PubMed Central

    Nance, John W.; Khurram, Irfan M.; Nazarian, Saman; DeWire, Jane; Calkins, Hugh; Zimmerman, Stefan L.

    2015-01-01

    Abstract Cardiac magnetic resonance (CMR) imaging is increasingly used to evaluate patients with atrial fibrillation (AF) before pulmonary vein antral isolation (PVAI). The purpose of this study was to assess the incidence and pattern of left ventricular (LV) late gadolinium enhancement (LGE) in patients undergoing CMR before PVAI and compare the clinical and demographic differences of patients with and without LV LGE. Clinical and demographic data on 62 patients (mean age 61 ± 7.9, 69% male) undergoing CMR before PVAI for AF were collected. Two observers, masked to clinical histories, independently recorded the prevalence, extent (number of myocardial segments), and pattern (subendocardial, midmyocardial, or subepicardial) of LV LGE in each patient. Clinical and demographic predictors of LV LGE were determined using logistic regression. Twenty-three patients (37%) demonstrated LV LGE affecting a mean of 3.0 ± 2.1 myocardial segments. There was no difference in LV ejection fraction between patients with and without LGE, and most (65%) patients with LGE had normal wall motion. Only age (P = 0.04) and a history of congestive heart failure (P = .03) were statistically significant independent predictors of LGE. The most common LGE pattern was midmyocardial, seen in 17 of 23 (74%) patients. Only 4 of 23 (17%) patients had LGE in an “expected” pattern based on clinical history. Of the remaining 19 patients, 4 had known congestive heart failure, 5 nonischemic cardiomyopathy, 4 known coronary artery disease, and 2 prior aortic valve replacement. Six of 23 (26%) patients had no known coronary artery, valvular, or myocardial disease. There is a high prevalence of unexpected LV scar in patients undergoing CMR before PVAI for AF, with most patients demonstrating a nonischemic pattern of LV LGE and no wall motion abnormalities (ie, subclinical disease). The high prevalence of unexpected LGE in these patients may argue for CMR as the modality of choice for

  11. Association of Late Gadolinium Enhancement and Degree of Left Ventricular Hypertrophy Assessed on Cardiac Magnetic Resonance Imaging With Ventricular Tachycardia in Children With Hypertrophic Cardiomyopathy.

    PubMed

    Spinner, Joseph A; Noel, Cory V; Denfield, Susan W; Krishnamurthy, Rajesh; Jeewa, Aamir; Dreyer, William J; Maskatia, Shiraz A

    2016-04-15

    There are limited data on the clinical significance of left ventricular (LV) mass and late gadolinium enhancement (LGE) in pediatric hypertrophic cardiomyopathy (HC). We reviewed cardiovascular magnetic resonance (CMR) studies of children with HC to investigate the associations between the extent and distribution of LGE and LV mass with ventricular tachycardia (VT) in children with HC. A blinded observer reviewed CMR studies for the presence and distribution of LV hypertrophy and LGE using a 17-segment model. The primary outcome was VT. LGE was present 17 of 33 subjects (52%). VT was present on outpatient Holter monitor or exercise stress test in 7 patients, of which 5 patients (71%) had LGE. Each additional segment of LGE was associated with an increase in the odds of VT (odds ratio [OR] 1.4, 95% CI 1.1 to 1.9) and fewer than 5 segments with LGE had 93% specificity for the presence or absence of VT (OR 0.06, 95% CI 0.01 to 0.5). VT was more common in patients with LGE in the apical septal (p = 0.03), basal inferoseptal (p <0.01), and basal inferior (p = 0.04) segments, whereas LGE in more commonly involved segments (midanteroseptal and midinferoseptal) was not associated with VT (p = 0.13, 0.26). Patients with VT had greater LV mass index (76.4 ± 40.4 g/m(2.7) vs 50.9 ± 24.3 g/m(2.7); p = 0.03). Each centimeter of increased maximum LV thickness was associated with increased likelihood of VT (OR 2.9, 95% CI 1.2 to 6.8). In conclusion, in pediatric HC, CMR to evaluate the extent and pattern of LGE, LV mass index, and maximum LV thickness may help to identify children with HC at risk of VT. PMID:26892450

  12. Gadolinium-enhanced magnetic resonance angiography in brain death

    NASA Astrophysics Data System (ADS)

    Luchtmann, M.; Beuing, O.; Skalej, M.; Kohl, J.; Serowy, S.; Bernarding, J.; Firsching, R.

    2014-01-01

    Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

  13. In Vivo Tracking of Phagocytic Immune Cells Using a Dual Imaging Probe with Gadolinium-Enhanced MRI and Near-Infrared Fluorescence.

    PubMed

    Kim, Eun-Joong; Bhuniya, Sankarprasad; Lee, Hyunseung; Kim, Hyun Min; Shin, Weon Sup; Kim, Jong Seung; Hong, Kwan Soo

    2016-04-27

    A novel dual imaging probe for in vivo magnetic resonance imaging (MRI) and optical imaging was developed by combining gadolinium (Gd)-chelating MR probe and a near-infrared (NIR) fluorophore, aza-BODIPY (AB; BODIPY = boron-dipyrromethene). This aza-BODIPY-based bimodal contrast agent (AB-BCA) showed a significant fluorescence emission around the NIR range and an enhanced longitudinal relaxivity in MR modality. The probe was easily delivered to phagocytic cells of the innate immune system, together with macrophages and dendritic cells (DCs), and presented high-performance fluorescence and MR imaging without obvious cytotoxicity. For in vivo visualization of AB-BCA using MRI and optical imaging, bone marrow-derived DCs were labeled and injected into the footpad of mice, and labeled DCs were tracked in vivo. We observed the migration of AB-BCA-labeled DCs into the lymph nodes via lymphatic vessels using NIR fluorescence and T1-weighted MR images. This dual-modality imaging probe was used for noninvasive monitoring of DC migration into lymph nodes and could be useful for investigating advanced cellular immunotherapy. PMID:27058603

  14. Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement.

    PubMed

    Kebed, Kalie Y; Al Adham, Raed I; Bishu, Kalkidan; Askew, J Wells; Klarich, Kyle W; Araoz, Philip A; Foley, Thomas A; Glockner, James F; Nishimura, Rick A; Anavekar, Nandan S

    2014-09-01

    Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness. PMID:25037678

  15. Hypertrophic olivary degeneration with gadolinium enhancement after posterior fossa surgery in a child with medulloblastoma.

    PubMed

    Nowak, Johannes; Alkonyi, Balint; Rutkowski, Stefan; Homola, György A; Warmuth-Metz, Monika

    2014-05-01

    Hypertrophic olivary degeneration (HOD) is a rare transsynaptic form of degeneration occurring secondary to the disruption of the dentato-rubro-olivary pathway ("Guillain-Mollaret triangle"). HOD can be caused by ischemic, hemorrhagic, traumatic, or neoplastic lesions, and it can also occur following posterior fossa surgery. MRI characteristics of HOD include T2 signal increase and hypertrophy. To date, blood–brain barrier disruption has not been reported in HOD. Here, we present the first case of HOD with temporary gadolinium enhancement in a 10-year-old child 7 months after resection of a posterior fossa medulloblastoma. The recognition of gadolinium enhancement as a radiological feature of HOD may help to distinguish between this benign secondary condition and tumor recurrence. PMID:24122017

  16. Delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: pearls and pitfalls

    PubMed Central

    Bittersohl, Bernd; Zilkens, Christoph; Kim, Young-Jo; Werlen, Stefan; Siebenrock, Klaus A.; Mamisch, Tallal C.; Hosalkar, Harish S.

    2011-01-01

    With the increasing advances in hip joint preservation surgery, accurate diagnosis and assessment of femoral head and acetabular cartilage status is becoming increasingly important. Magnetic resonance imaging (MRI) of the hip does present technical difficulties. The fairly thin cartilage lining necessitates high image resolution and high contrast-to-noise ratio (CNR). With MR arthrography (MRA) using intraarticular injected gadolinium, labral tears and cartilage clefts may be better identified through the contrast medium filling into the clefts. However, the ability of MRA to detect varying grades of cartilage damage is fairly limited and early histological and biochemical changes in the beginning of osteoarthritis (OA) cannot be accurately delineated. Traditional MRI thus lacks the ability to analyze the biological status of cartilage degeneration. The technique of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is sensitive to the charge density of cartilage contributed by glycosaminoglycans (GAGs), which are lost early in the process of OA. Therefore, the dGEMRIC technique has a potential to detect early cartilage damage that is obviously critical for decision-making regarding time and extent of intervention for joint-preservation. In the last decade, cartilage imaging with dGEMRIC has been established as an accurate and reliable tool for assessment of cartilage status in the knee and hip joint. This review outlines the current status of dGEMRIC for assessment of hip joint cartilage. Practical modifications of the standard technique including three-dimensional (3D) dGEMRIC and dGEMRIC after intra-articular gadolinium instead of iv-dGEMRIC will also be addressed. PMID:22053252

  17. Delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: pearls and pitfalls.

    PubMed

    Bittersohl, Bernd; Zilkens, Christoph; Kim, Young-Jo; Werlen, Stefan; Siebenrock, Klaus A; Mamisch, Tallal C; Hosalkar, Harish S

    2011-01-01

    With the increasing advances in hip joint preservation surgery, accurate diagnosis and assessment of femoral head and acetabular cartilage status is becoming increasingly important. Magnetic resonance imaging (MRI) of the hip does present technical difficulties. The fairly thin cartilage lining necessitates high image resolution and high contrast-to-noise ratio (CNR). With MR arthrography (MRA) using intraarticular injected gadolinium, labral tears and cartilage clefts may be better identified through the contrast medium filling into the clefts. However, the ability of MRA to detect varying grades of cartilage damage is fairly limited and early histological and biochemical changes in the beginning of osteoarthritis (OA) cannot be accurately delineated. Traditional MRI thus lacks the ability to analyze the biological status of cartilage degeneration. The technique of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is sensitive to the charge density of cartilage contributed by glycosaminoglycans (GAGs), which are lost early in the process of OA. Therefore, the dGEMRIC technique has a potential to detect early cartilage damage that is obviously critical for decision-making regarding time and extent of intervention for joint-preservation. In the last decade, cartilage imaging with dGEMRIC has been established as an accurate and reliable tool for assessment of cartilage status in the knee and hip joint.This review outlines the current status of dGEMRIC for assessment of hip joint cartilage. Practical modifications of the standard technique including three-dimensional (3D) dGEMRIC and dGEMRIC after intra-articular gadolinium instead of iv-dGEMRIC will also be addressed. PMID:22053252

  18. Reproducibility of Gadolinium Enhancement Patterns and Wall Thickness in Hypertrophic Cardiomyopathy

    PubMed Central

    Rodriguez-Granillo, Gaston A.; Deviggiano, Alejandro; Capunay, Carlos; Zan, Macarena C. De; Carrascosa, Patricia

    2016-01-01

    Background Reproducibility data of the extent and patterns of late gadolinium enhancement (LGE) in hypertrophic cardiomyopathy (HCM) is limited. Objective To explore the reproducibility of regional wall thickness (WT), LGE extent, and LGE patterns in patients with HCM assessed with cardiac magnetic resonance (CMR). Methods The extent of LGE was assessed by the number of segments with LGE, and by the total LV mass with LGE (% LGE); and the pattern of LGE-CMR was defined for each segment. Results A total of 42 patients (672 segments) with HCM constituted the study population. The mean WT measurements showed a mean difference between observers of -0.62 ± 1.0 mm (6.1%), with limits of agreement of 1.36 mm; -2.60 mm and intraclass correlation coefficient (ICC) of 0.95 (95% CI 0.93-0.96). Maximum WT measurements showed a mean difference between observers of -0.19 ± 0.8 mm (0.9%), with limits of agreement of 1.32 mm; -1.70 mm, and an ICC of 0.95 (95% CI 0.91-0.98). The % LGE showed a mean difference between observers of -1.17 ± 1.2 % (21%), with limits of agreement of 1.16%; -3.49%, and an ICC of 0.94 (95% CI 0.88-0.97). The mean difference between observers regarding the number of segments with LGE was -0.40 ± 0.45 segments (11%), with limits of agreement of 0.50 segments; -1.31 segments, and an ICC of 0.97 (95% CI 0.94-0.99). Conclusions The number of segments with LGE might be more reproducible than the percent of the LV mass with LGE. PMID:27305110

  19. MRI of the left atrium: predicting clinical outcomes in patients with atrial fibrillation.

    PubMed

    Daccarett, Marcos; McGann, Chris J; Akoum, Nazem W; MacLeod, Rob S; Marrouche, Nassir F

    2011-01-01

    Atrial fibrillation is a significant public health burden, with clinically, epidemiologically and economically significant repercussions. In the last decade, catheter ablation has provided an improvement in morbidity and quality of life, significantly reducing long-term healthcare costs and avoiding recurrences compared with drug therapy. Despite recent progress in techniques, current catheter ablation success rates fall short of expectations. Late gadolinium-enhancement cardiovascular MRI is a well-established tool to image the myocardium and, most specifically, the left atrium. Unique imaging protocols allow for left atrial structural remodeling and fibrosis assessment, which has been demonstrated to correlate with clinical outcomes after catheter ablation, assessment of the individual's risks of thromboembolic events, and effective imaging of patients with left atrial appendage thrombus. Late gadolinium-enhancement MRI aids in the individualized treatment of atrial fibrillation, stratifying recurrence risk and guiding specific ablation strategies. Real-time MRI offers significant safety and effectiveness profiles that would optimize the invasive treatment of atrial fibrillation. PMID:21166532

  20. Unique pattern of late gadolinium enhancement on cardiac magnetic resonance imaging in Duchenne muscular dystrophy

    PubMed Central

    Ganigara, Madhusudan; Sharma, Bharti; Komalla, Ravi Babu; Vyas, Suman Y.; Mannam, Gopichand; Rao, Nitin Krishna

    2016-01-01

    Cardiomyopathy is an important cause of morbidity and mortality in patients with Duchenne muscular dystrophy (DMD). Early recognition of myocardial involvement and initiation of therapy are important for improved outcomes. Cardiac magnetic resonance imaging (CMR) is a sensitive tool in early detection of myocardial fibrosis in these children. PMID:27212861

  1. Unique pattern of late gadolinium enhancement on cardiac magnetic resonance imaging in Duchenne muscular dystrophy.

    PubMed

    Ganigara, Madhusudan; Sharma, Bharti; Komalla, Ravi Babu; Vyas, Suman Y; Mannam, Gopichand; Rao, Nitin Krishna

    2016-01-01

    Cardiomyopathy is an important cause of morbidity and mortality in patients with Duchenne muscular dystrophy (DMD). Early recognition of myocardial involvement and initiation of therapy are important for improved outcomes. Cardiac magnetic resonance imaging (CMR) is a sensitive tool in early detection of myocardial fibrosis in these children. PMID:27212861

  2. [Stress cardiac MRI in management of ischemic heart disease].

    PubMed

    Russel, S; Darmon, S; Vermillet, A; Haziza, F

    2014-11-01

    Stress magnetic cardiac resonance imaging (MRI) development is in progress. Many cardiac imaging technics already known are completed by this safe radiation free exam with a short time acquisition (30minutes) and a good diagnostic performance in particular for patients with three vessels coronary artery diseases. Best indication concerns symptomatic patients unable to exercise with intermediate or high pretest probability. Pharmacological heart stress can be induced with vasodilatators or dobutamine to identify the presence and extent of myocardial ischemia, with high precision to guide coronary vessels revascularization. MRI gives many other interesting informations like heart anatomy, left ventricular function. Myocardial viability can be assessed with study of late gadolinium enhancement or analysis of contractile reserve with low dose of dobutamine. PMID:25281219

  3. Gadolinium-enhanced inner ear magnetic resonance imaging for evaluation of delayed endolymphatic hydrops, including a bilateral case.

    PubMed

    Fukushima, Munehisa; Oya, Ryohei; Akazawa, Hitoshi; Tsuruta, Yukinori; Inohara, Hidenori

    2016-05-01

    Conclusion The data suggests that gadolinium-enhanced inner ear MR imaging is useful for diagnosis of delayed endolymphatic hydrops (DEH) because it is independent of inner ear function, and the size of the affected endolymphatic space is clearly enlarged. Objective This study was performed to semi-quantitatively evaluate the endolymphatic space in patients with all types of DEH using gadolinium-enhanced inner ear magnetic resonance (MR) imaging. Patients and methods Seven patients (age range = 21-77 years; five female, two male) with ipsilateral DEH (n = 5), contralateral DEH (n = 1), and bilateral DEH (n = 1). All patients underwent 3T MR imaging 4 h after intravenous injection of gadolinium. Software was used to determine the size of the endolymphatic space. Pure tone audiometry and caloric testing using an electronystagmogram were carried out. Results One side of the endolymphatic space was dominantly extended in patients with ipsilateral DEH, and both sides of the space were extended in patients with contralateral and bilateral DEH. In patients with ipsilateral DEH, the volume ratio of endolymph to vestibule was 2.5-4.3-times that in the unaffected ear. The volume ratio of endolymph to vestibule was nearly equal in patients with contralateral and bilateral DEH. PMID:26799493

  4. Day of Injury CT and Late MRI Findings: Cognitive Outcome in a Pediatric Sample with Complicated Mild Traumatic Brain Injury

    PubMed Central

    Jantz, Paul B; Farrer, Thomas J.; Abildskov, Tracy J.; Dennis, Maureen; Gerhardt, Cynthia A.; Rubin, Kenneth H.; Stancin, Terry; Taylor, H. Gerry; Vannatta, Kathryn; Yeates, Keith Owen

    2016-01-01

    Objectives Complicated mild traumatic brain injury (mTBI) or cmTBI is based on the presence of visibly identifiable brain pathology on the day-of-injury computed tomography (CT) scan. In a pediatric sample the relation of DOI CT to late MRI findings and neuropsychological outcome was examined. Methods MRI (> 12 months) was obtained in pediatric cmTBI patients and a sample of orthopedically injured (OI) children. Those children with positive imaging findings (MRI+) were quantitatively compared to those without (MRI-) or with the OI sample. Groups were also compared in neurocognitive outcome from WASI subtests and the WISC-IV Processing Speed Index (PSI), along with the Test of Everyday Attention for Children (TEA-Ch) and a parent-rated behavioral functioning measure (ABAS-II). Results Despite the MRI+ group having significantly more DOI CT findings than the MRI-group, no quantitative differences were found. WASI Vocabulary and Matrix Reasoning scores were significantly lower, but not PSI, TEA-Ch or ABAS-II scores. MRI+ and MRI-groups did not differ on these measures. Conclusions Heterogeneity in the occurrence of MRI-identified focal pathology was not associated with uniform changes in quantitative analyses of brain structure in cmTBI. Increased number of DOI CT abnormalities was associated with lowered neuropsychological performance. PMID:26186038

  5. Vertebral body corner oedema vs gadolinium enhancement as biomarkers of active spinal inflammation in ankylosing spondylitis

    PubMed Central

    Wang, Y-X J; Griffith, J F; Deng, M; Li, T K; Tam, L-S; Lee, V W Y; Lee, K K C; Li, E K

    2012-01-01

    Objective To investigate the relative performance of T2 weighted short tau inversion–recovery (STIR) and fat-suppressed T1 weighted gadolinium contrast-enhanced sequences in depicting active inflammatory lesions in ankylosing spondylitis (AS). Methods Whole-spine MRI was performed on 32 patients with AS, who participated in a clinical trial of infliximab treatment, by STIR and contrast-enhanced sequences at baseline and after 30 weeks. The AS spine MRI-activity (ASspiMRI-a) scoring method was used. The images from these two imaging techniques were evaluated separately by two independent readers. Results For the pre-treatment lesion status, the intraclass correlation coefficients comparing STIR readings and contrast-enhanced readings were 0.69±0.23 for Reader 1 and 0.65±0.21 for Reader 2. At baseline, the mean ASspiMRI-a score was 15.4% and 17.7% higher for contrast-enhanced images than for STIR images for Reader 1 and Reader 2, respectively. After infliximab treatment, Reader 1 rated an ASspiMRI-a score reduction of 50.8±33.6% and 25.3±35.3% for STIR images and contrast-enhanced images, respectively, whereas Reader 2 rated an ASspiMRI-a score reduction of 42.4±50.4% and 32.9±35.6% for STIR images and contrast-enhanced images, respectively. Conclusion While both contrast-enhanced and STIR sequences showed sensitivity to change over a short period of time after infliximab treatment, these two sequences may reflect different disease mechanisms. PMID:22595499

  6. Mesenteric circulation: three-dimensional MR angiography with a gadolinium-enhanced multiecho gradient-echo technique.

    PubMed

    Shirkhoda, A; Konez, O; Shetty, A N; Bis, K G; Ellwood, R A; Kirsch, M J

    1997-01-01

    To evaluate the mesenteric circulation with magnetic resonance (MR) angiography, the authors examined 16 individuals (12 patients, four volunteers) with a gadolinium-enhanced, breath-hold, fat-saturated, multiecho, three-dimensional, gradient-echo sequence. Twenty examinations were performed. Grades of 3 or 4 (on a five-point scale [4 = best seen, 0 = not seen]) were applicable to 17 (85%) of 20 MR angiograms obtained in superior mesenteric artery trunks, 15 (75%) in celiac arteries, five (25%) in inferior mesenteric arteries; 15 (75%) of first-order branching, 12 (60%) of second-order branching, and 10 (50%) of third-order branching; 17 (85%) in superior mesenteric veins; and 17 (85%) in portal veins. MR angiography with this technique depicted the mesenteric arterial and venous circulation and the portal vein with excellent resolution in a short time. PMID:8988220

  7. PET/MRI assessment of the infarcted mouse heart

    NASA Astrophysics Data System (ADS)

    Buonincontri, Guido; Methner, Carmen; Krieg, Thomas; Hawkes, Robert C.; Adrian Carpenter, T.; Sawiak, Stephen J.

    2014-01-01

    Heart failure originating from myocardial infarction (MI) is a leading cause of death worldwide. Mouse models of ischaemia and reperfusion injury (I/R) are used to study the effects of novel treatment strategies targeting MI, however staging disease and treatment efficacy is a challenge. Damage and recovery can be assessed on the cellular, tissue or whole-organ scale but these are rarely measured in concert. Here, for the first time, we present data showing measures of injury in infarcted mice using complementary techniques for multi-modal characterisation of the heart. We use in vivo magnetic resonance imaging (MRI) to assess heart function with cine-MRI, hindered perfusion with late gadolinium enhancement imaging and muscular function with displacement encoded with stimulated echoes (DENSE) MRI. These measures are followed by positron emission tomography (PET) with 18-F-fluorodeoxyglucose to assess cellular metabolism. We demonstrate a protocol combining each of these measures for the same animal in the same imaging session and compare how the different markers can be used to quantify cardiac recovery on different scales following injury.

  8. Postmortem MRI: a novel window into the neurobiology of late life cognitive decline.

    PubMed

    Dawe, Robert J; Yu, Lei; Leurgans, Sue E; Schneider, Julie A; Buchman, Aron S; Arfanakis, Konstantinos; Bennett, David A; Boyle, Patricia A

    2016-09-01

    This study tested the hypothesis that indices of brain tissue integrity derived from postmortem magnetic resonance imaging (MRI) are associated with late life decline in cognitive function and dementia, over and above contributions from common age-related neuropathologies. Cerebral hemispheres were obtained from 425 deceased older adults who had undergone 2 or more annual cognitive assessments, which included clinical diagnosis of dementia. Specimens underwent MRI to produce maps of transverse relaxation rate, R2. Voxelwise regression revealed brain regions where R2 was associated with cognitive decline. We then used random effects models to quantify the extent to which R2 accounted for variation in decline, after adjustment for demographics and neuropathologic indices of the 3 most common causes of dementia: Alzheimer's disease, cerebrovascular disease, and Lewy body disease. We additionally tested whether R2 was tied to greater likelihood of clinical diagnosis of Alzheimer's dementia using logistic regression models. During an average of 8.1 years, the mean rate of decline in global cognitive function was 0.13 unit per year (p < 0.0001). The tissue alteration most commonly related to decline was R2 slowing in white matter. Each unit decrease in R2 was associated with an additional 0.053-unit per year steepening of the rate of global cognitive decline (p < 0.001). Furthermore, R2 accounted for 8.4% of the variance in rate of global cognitive decline, above and beyond the 26.5% accounted for by demographics and neuropathologic indices, and 7.1%-11.2% of the variance of the decline rates in episodic, semantic, and working memory and perceptual speed. Alterations in R2 were also related to an increased odds of clinical diagnosis of Alzheimer's dementia (odds ratio = 2.000, 95% confidence interval 1.600, 2.604). Therefore, postmortem MRI indices of brain tissue integrity, particularly in white matter, are useful for elucidating the basis of late life cognitive

  9. Risk stratification for major adverse cardiac events and ventricular tachyarrhythmias by cardiac MRI in patients with cardiac sarcoidosis

    PubMed Central

    Yasuda, Masakazu; Iwanaga, Yoshitaka; Kato, Takao; Izumi, Toshiaki; Inuzuka, Yasutaka; Nakamura, Takashi; Miyaji, Yuki; Kawamura, Takayuki; Ikeguchi, Shigeru; Inoko, Moriaki; Kurita, Takashi; Miyazaki, Shunichi

    2016-01-01

    Background The presence of myocardial fibrosis by cardiac MRI has prognostic value in cardiac sarcoidosis, and localisation may be equally relevant to clinical outcomes. Objective We aimed to analyse cardiac damage and function in detail and explore the relationship with clinical outcomes in patients with cardiac sarcoidosis using cardiac MRI. Methods We included 81 consecutive patients with cardiac sarcoidosis undergoing cardiac MR. Left ventricular mass and fibrosis mass were calculated, and localisation was analysed using a 17-segment model. Participants underwent follow-up through 2015, and the development of major adverse cardiac events including ventricular tachyarrhythmias was recorded. Results Increased left ventricular fibrosis mass was associated with increased prevalence of ventricular tachyarrhythmias (p<0.001). When localisation was defined as the sum of late gadolinium enhancement in the left ventricular basal anterior and basal anteroseptal areas, or the right ventricular area, it was associated with ventricular tachyarrhythmias (p<0.001). Kaplan-Meier analysis during a median follow-up of 22.1 months showed that both the mass and localisation groupings for fibrosis were significantly associated with major adverse cardiac events or ventricular tachyarrhythmias and that when combined, the risk stratification was better than for each variable alone (p<0.001, respectively). By Cox-proportional hazard risk analysis, the localisation grouping was an independent predictor for the both. Conclusions In patients with cardiac sarcoidosis, both fibrosis mass and its localisation to the basal anterior/anteroseptal left ventricle, or right ventricle was associated with the development of major adverse cardiac events or ventricular tachyarrhythmias. Cardiac MR with late gadolinium enhancement may be useful for improving risk stratification in patients with cardiac sarcoidosis. PMID:27547432

  10. Differences in early and late mild cognitive impairment tractography using a diffusion tensor MRI.

    PubMed

    Lee, Seung-Hak; Seo, Jongbum; Lee, Jong-min; Park, Hyunjin

    2014-12-01

    Diffusion tensor MRI tractography is an imaging tool that can provide information of in-vivo neuronal fiber tracts to assess progress for Alzheimer's disease (AD). In an effort to detect early AD progression, we focused on distinguishing subgroups within mild cognitive impairment (MCI): early MCI and late MCI. Tractography was applied not only to white matter regions but also neighboring gray matter regions known to be affected by AD. Nerve fibers touching the hippocampus, thalamus, and amygdala in both hemispheres were extracted to quantify limbic system fiber connectivity. Two fiber extraction algorithms, fiber assignment by continuous tracking and the Runge Kutta approach, were applied to an AD imaging database. We computed the number of fibers touching regions of interest as the imaging feature. The imaging feature could distinguish between the MCI subgroups. It was also significantly correlated with a known genetic marker for AD, the apolipoprotein E epsilon 4 allele. The number of fibers might be a useful imaging biomarker to complement conventional region of interest-based biomarkers for AD research. PMID:25325351

  11. Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

    SciTech Connect

    Deli, Martin; Mateiescu, Serban Busch, Martin; Becker, Jan Garmer, Marietta Groenemeyer, Dietrich

    2013-06-15

    Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 with gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 {+-} 9 min in the gadolinium-enhanced saline solution group and 22 {+-} 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.

  12. Intramyocardial Hemorrhage: An Enigma for Cardiac MRI?

    PubMed Central

    Masselli, Gabriele; Monti, Riccardo; Spreca, Matteo; Gualdi, Gian Franco

    2015-01-01

    Cardiovascular magnetic resonance (CMR) is a useful noninvasive technique for determining the presence of microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH), frequently occurring in patients after reperfused myocardial infarction (MI). MVO, or the so-called no-reflow phenomenon, is associated with adverse ventricular remodeling and a poor prognosis during follow-up. Similarly, IMH is considered a severe damage after revascularization by percutaneous primary coronary intervention (PPCI) or fibrinolysis, which represents a worse prognosis. However, the pathophysiology of IMH is not fully understood and imaging modalities might help to better understand that phenomenon. While, during the past decade, several studies examined the distribution patterns of late gadolinium enhancement with different CMR sequences, the standardized CMR protocol for assessment of IMH is not yet well established. The aim of this review is to evaluate the available literature on this issue, with particular regard to CMR sequences. New techniques, such as positron emission tomography/magnetic resonance imaging (PET/MRI), could be useful tools to explore molecular mechanisms of the myocardial infarction healing process. PMID:25759823

  13. Identification and Acute Targeting of Gaps in Atrial Ablation Lesion Sets using a Real Time MRI System

    PubMed Central

    Ranjan, Ravi; Kholmovski, Eugene G.; Blauer, Joshua; Vijayakumar, Sathya; Volland, Nelly A.; Salama, Mohamed E.; Parker, Dennis L.; MacLeod, Rob; Marrouche, Nassir F.

    2013-01-01

    Background Radiofrequency ablation is routinely used to treat cardiac arrhythmias, but gaps remain in ablation lesion sets, as there is no direct visualization of ablation related changes. In this study we describe using a real time MRI (RT-MRI) system to acutely identify and target gaps leading to a complete and transmural ablation in the atrium. Methods and Results A swine model was used for these studies (n=12). Ablation lesions with a gap were created in the atrium using fluoroscopy and an electro-anatomical system in the first group (n=5). The animal was then moved to a 3 Tesla MRI system where high-resolution late gadolinium enhancement (LGE) MRI was used to identify the gap. Using a RT-MRI catheter navigation and visualization system the gap area was ablated in the MR scanner. In a second group (n=7) ablation lesions with varying gaps in between were created under RT-MRI guidance and gap lengths determined using LGE MR images were correlated with gap length measured from gross pathology. Gaps up to 1.0 mm were identified using gross pathology and 1.4 mm using LGE MRI. Using a RT-MRI system with active catheter navigation gaps can be targeted acutely, leading to lesion sets with no gaps. The correlation coefficient (R2) between gap length identified using MRI and gross pathology was 0.95. Conclusions Real time MRI system can be used to identify and acutely target gaps in atrial ablation lesion sets. Acute targeting of gaps in ablation lesion sets can potentially lead to significant improvement in clinical outcomes. PMID:23071143

  14. Gadolinium Enhanced MR-angiography Results in Patients With Peripheral Arterial Disease: Positive Predictive Value Compared to Surgery

    PubMed Central

    Mirsharifi, Seyed Rasool; Noparast, Morteza; Khazravi, Mona; Ghanaati, Hossein; Shakiba, Majid; Sharifi, Amirsina

    2014-01-01

    Background: Peripheral arterial disease (PAD) represents systematic atherosclerosis of great vessels. PAD affects approximately 10-20 % of patients older than 60 years and is associated with high mortality and morbidity rate debilitating individuals’ life. Objectives: To compare the results of Gadolinium enhanced MR-Angiography and surgery in patients suspected to have peripheral arterial disease. Materials and Methods: In this prospective cohort study, 30 consecutive patients matching the inclusion criteria were enrolled and MR-Angiography was performed prior to surgery for each one. Results: 22 patients were male (73.3%) and the mean age was 60.3 ± 10.6 years in our study group. The most common artery for cut off and run off was superior femoral artery in both assessments. Proximal section of each artery was the most common anatomical section for cut off and run off. There was a same report of cut off artery by MR-Angiography and surgery (kappa coefficient of agreement was 0.96, P value < 0.001) and positive predictive value was 0.97 (95% CI: 0.83-0.99). Conclusions: According to our findings MR-angiography is an appropriate alternative imaging modality for patients suspected to have peripheral arterial disease and it facilitates the early diagnosis proposed by the clinical findings. Also beneficial characteristics of this method such as low exposure to ionizing radiation, repeatability, and low risk of contrast agent-induced nephropathy make it a modality of choice in patients with renal impairment. PMID:25763247

  15. Adaptive Changes in Early and Late Blind: A fMRI Study of Braille Reading

    PubMed Central

    SNYDER, A. Z.; CONTURO, T. E.; AKBUDAK, E.; OLLINGER, J. M.; RAICHLE, M. E.

    2013-01-01

    Braille reading depends on remarkable adaptations that connect the somatosensory system to language. We hypothesized that the pattern of cortical activations in blind individuals reading Braille would reflect these adaptations. Activations in visual (occipital-temporal), frontal-language, and somatosensory cortex in blind individuals reading Braille were examined for evidence of differences relative to previously reported studies of sighted subjects reading print or receiving tactile stimulation. Nine congenitally blind and seven late-onset blind subjects were studied with fMRI as they covertly performed verb generation in response to reading Braille embossed nouns. The control task was reading the nonlexical Braille string “######”. This study emphasized image analysis in individual subjects rather than pooled data. Group differences were examined by comparing magnitudes and spatial extent of activated regions first determined to be significant using the general linear model. The major adaptive change was robust activation of visual cortex despite the complete absence of vision in all subjects. This included foci in peri-calcarine, lingual, cuneus and fusiform cortex, and in the lateral and superior occipital gyri encompassing primary (V1), secondary (V2), and higher tier (VP, V4v, LO and possibly V3A) visual areas previously identified in sighted subjects. Subjects who never had vision differed from late blind subjects in showing even greater activity in occipital-temporal cortex, provisionally corresponding to V5/MT and V8. In addition, the early blind had stronger activation of occipital cortex located contralateral to the hand used for reading Braille. Responses in frontal and parietal cortex were nearly identical in both subject groups. There was no evidence of modifications in frontal cortex language areas (inferior frontal gyrus and dorsolateral prefrontal cortex). Surprisingly, there was also no evidence of an adaptive expansion of the somatosensory or

  16. Review of Source Images is Necessary for the Evaluation of Gadolinium-Enhanced MR Angiography for Renal Artery Stenosis

    SciTech Connect

    Wehrschuetz, M. Aschauer, M.; Portugaller, H.; Stix, A.; Wehrschuetz-Sigl, E.; Hausegger, K.; Ebner, F.

    2004-09-15

    The purpose of this study was to assess interobserver variability and accuracy in the evaluation of renal artery stenosis (RAS) with gadolinium-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in patients with hypertension. The authors found that source images are more accurate than maximum intensity projection (MIP) for depicting renal artery stenosis. Two independent radiologists reviewed MRA and DSA from 38 patients with hypertension. Studies were postprocessed to display images in MIP and source images. DSA was the standard for comparison in each patient. For each main renal artery, percentage stenosis was estimated for any stenosis detected by the two radiologists. To calculate sensitivity, specificity and accuracy, MRA studies and stenoses were categorized as normal, mild (1-39%), moderate (40-69%) or severe ({>=}70%), or occluded. DSA stenosis estimates of 70% or greater were considered hemodynamically significant. Analysis of variance demonstrated that MIP estimates of stenosis were greater than source image estimates for both readers. Differences in estimates for MIP versus DSA reached significance in one reader. The interobserver variance for MIP, source images and DSA was excellent (0.80< {kappa}{<=} 0.90). The specificity of source images was high (97%) but less for MIP (87%); average accuracy was 92% for MIP and 98% for source images. In this study, source images are significantly more accurate than MIP images in one reader with a similar trend was observed in the second reader. The interobserver variability was excellent. When renal artery stenosis is a consideration, high accuracy can only be obtained when source images are examined.

  17. MRI

    MedlinePlus

    ... scan is an imaging test that uses powerful magnets and radio waves to create pictures of the ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  18. Visualising uncertainty: Examining women's views on the role of Magnetic Resonance Imaging (MRI) in late pregnancy.

    PubMed

    Reed, Kate; Kochetkova, Inna; Whitby, Elspeth

    2016-09-01

    Prenatal screening occupies a prominent role within sociological debates on medical uncertainty. A particular issue concerns the limitations of routine screening which tends to be based on risk prediction. Computer assisted visual technologies such as Magnetic Resonance Imaging (MRI) are now starting to be applied to the prenatal realm to assist in the diagnosis of a range of fetal and maternal disorders (from problems with the fetal brain to the placenta). MRI is often perceived in popular and medical discourse as a technology of certainty and truth. However, little is known about the use of MRI as a tool to confirm or refute the diagnosis of a range of disorders in pregnancy. Drawing on qualitative research with pregnant women attending a fetal medicine clinic in the North of England this paper examines the potential role that MRI can play in mediating pregnancy uncertainty. The paper will argue that MRI can create and manage women's feelings of uncertainty during pregnancy. However, while MRI may not always provide women with unequivocal answers, the detailed information provided by MR images combined with the interpretation and communication skills of the radiologist in many ways enables women to navigate the issue. Our analysis of empirical data therefore highlights the value of this novel technological application for women and their partners. It also seeks to stress the merit of taking a productive approach to the study of diagnostic uncertainty, an approach which recognises the concepts dual nature. PMID:27451338

  19. Diagnostic accuracy of late iodine enhancement on cardiac computed tomography with a denoise filter for the evaluation of myocardial infarction.

    PubMed

    Matsuda, Takuya; Kido, Teruhito; Itoh, Toshihide; Saeki, Hideyuki; Shigemi, Susumu; Watanabe, Kouki; Kido, Tomoyuki; Aono, Shoji; Yamamoto, Masaya; Matsuda, Takeshi; Mochizuki, Teruhito

    2015-12-01

    We evaluated the image quality and diagnostic performance of late iodine enhancement (LIE) in dual-source computed tomography (DSCT) with low kilo-voltage peak (kVp) images and a denoise filter for the detection of acute myocardial infarction (AMI) in comparison with late gadolinium enhancement (LGE) magnetic resonance imaging (MRI). The Hospital Ethics Committee approved the study protocol. Before discharge, 19 patients who received percutaneous coronary intervention after AMI underwent DSCT and 1.5 T MRI. Immediately after coronary computed tomography (CT) angiography, contrast medium was administered at a slow injection rate. LIE-CT scans were acquired via dual-energy CT and reconstructed as 100-, 140-kVp, and mixed images. An iterative three-dimensional edge-preserved smoothing filter was applied to the 100-kVp images to obtain denoised 100-kVp images. The mixed, 140-kVp, 100-kVp, and denoised 100-kVp images were assessed using contrast-to-noise ratio (CNR), and their diagnostic performance in comparison with MRI and infarcted volumes were evaluated. Three hundred four segments of 19 patients were evaluated. Fifty-three segments showed LGE in MRI. The median CNR of the mixed, 140-, 100-kVp and denoised 100-kVp images was 3.49, 1.21, 3.57, and 6.08, respectively. The median CNR was significantly higher in the denoised 100-kVp images than in the other three images (P < 0.05). The denoised 100-kVp images showed the highest diagnostic accuracy and sensitivity. The percentage of myocardium in the four CT image types was significantly correlated with the respective MRI findings. The use of a denoise filter with a low-kVp image can improve CNR, sensitivity, and accuracy in LIE-CT. PMID:26202159

  20. A novel method for viability assessment by cinematographic and late contrast enhanced MRI

    NASA Astrophysics Data System (ADS)

    Gao, Gang; Cockshott, Paul W.; Martin, Thomas N.; Foster, John E.; Elliott, Alex; Dargie, Henry; Groenning, Bjoern A.

    2004-04-01

    Using cardiac magnetic resonance (MR) imaging, a combination of late contrast enhanced MR (ceMR) and cinematographic (CINE) images, a myocardial viability score can be derived. At present this score is produced by visual evaluation of wall motion abnormalities in combination with presence or absence of late hyper enhancement (LE) on ceMR. We set out to develop and validate image processing techniques derived from stereo vision capable of reducing the observer dependence and improving accuracy in the diagnosis of viable myocardium.

  1. Fear extinction, persistent disruptive behavior and psychopathic traits: fMRI in late adolescence.

    PubMed

    Cohn, Moran D; van Lith, Koen; Kindt, Merel; Pape, Louise E; Doreleijers, Theo A H; van den Brink, Wim; Veltman, Dick J; Popma, Arne

    2016-07-01

    Children diagnosed with a Disruptive Behavior Disorder (DBD, i.e. Oppositional Defiant Disorder or Conduct Disorder), especially those with psychopathic traits, are at risk of developing persistent and severe antisocial behavior. Reduced fear conditioning has been proposed to underlie persistent antisocial development. However, we have recently shown that both DBD persisters and desisters are characterized by increased fear conditioning compared with healthy controls (HCs). In this study, we investigated whether brain function during fear extinction is associated with DBD subgroup-membership and psychopathic traits. Adolescents from a childhood arrestee cohort (mean age 17.6 years, s.d. 1.4) who met criteria for a DBD diagnosis during previous assessments were re-assessed and categorized as persistent DBD (n = 25) or desistent DBD (n = 25). Functional MRI during the extinction phase of a classical fear-conditioning task was used to compare regional brain function between these subgroups and 25 matched controls. Both DBD persisters and desisters showed hyperreactivity during fear extinction, when compared with HCs. Impulsive-irresponsible psychopathic traits were positively associated with responses in the fear neurocircuitry and mediated the association between neural activation and group membership. These results suggest that fear acquisition and fear extinction deficits may provide an endophenotype for an emotionally hyperreactive subtype of antisocial development. PMID:26048179

  2. Classifying late-onset dementia with MRI: Is arteriosclerotic brain degeneration the most common cause of Alzheimer’s syndrome?

    PubMed Central

    Henry-Feugeas, Marie Cécile; Onen, Fannie; Claeys, Elisabeth Schouman

    2008-01-01

    Our aim was to use early magnetic resonance imaging (MRI) to investigate the causes of cognitive decline in elderly people with mild cognitive impairment (MCI). Baseline structural and flow quantification MR sequences, and clinical and neuropsychological follow-up for at least two years, were performed on 62 elderly subjects with MCI. Of these subjects, 17 progressed to dementia, and 15 of these progressed to dementia of the Alzheimer type (DAT). Conversion to clinically diagnosed DAT was related to six distinct MR profiles, including one profile suggesting severe AD (20% of these converters) and five profiles suggesting severe cerebrovascular dysfunction. Two profiles suggested arteriosclerotic brain degeneration, one profile suggested severe venous windkessel dysfunction, and two suggested marked cerebral hypoperfusion associated with very low craniospinal compliance or marked brain atrophy. As compared with vascular MR type converters, AD MR type converters showed high executive and mobility predementia performances. Severe whole anteromesial temporal atrophy and predominantly left brain atrophy on visual MR analysis was only observed in AD MR type converters. In conclusion, these observations enhance the pathogenic complexity of the Alzheimer syndrome, and suggest that the role of arteriosclerotic brain degeneration in late life dementia is underestimated. PMID:18488889

  3. Molecular MRI enables early and sensitive detection of brain metastases.

    PubMed

    Serres, Sébastien; Soto, Manuel Sarmiento; Hamilton, Alastair; McAteer, Martina A; Carbonell, W Shawn; Robson, Matthew D; Ansorge, Olaf; Khrapitchev, Alexandre; Bristow, Claire; Balathasan, Lukxmi; Weissensteiner, Thomas; Anthony, Daniel C; Choudhury, Robin P; Muschel, Ruth J; Sibson, Nicola R

    2012-04-24

    Metastasis to the brain is a leading cause of cancer mortality. The current diagnostic method of gadolinium-enhanced MRI is sensitive only to larger tumors, when therapeutic options are limited. Earlier detection of brain metastases is critical for improved treatment. We have developed a targeted MRI contrast agent based on microparticles of iron oxide that enables imaging of endothelial vascular cell adhesion molecule-1 (VCAM-1). Our objectives here were to determine whether VCAM-1 is up-regulated on vessels associated with brain metastases, and if so, whether VCAM-1-targeted MRI enables early detection of these tumors. Early up-regulation of cerebrovascular VCAM-1 expression was evident on tumor-associated vessels in two separate murine models of brain metastasis. Metastases were detectable in vivo using VCAM-1-targeted MRI 5 d after induction (<1,000 cells). At clinical imaging resolutions, this finding is likely to translate to detection at tumor volumes two to three orders of magnitude smaller (0.3-3 × 10(5) cells) than those volumes detectable clinically (10(7)-10(8) cells). VCAM-1 expression detected by MRI increased significantly (P < 0.0001) with tumor progression, and tumors showed no gadolinium enhancement. Importantly, expression of VCAM-1 was shown in human brain tissue containing both established metastases and micrometastases. Translation of this approach to the clinic could increase therapeutic options and change clinical management in a substantial number of cancer patients. PMID:22451897

  4. Molecular MRI enables early and sensitive detection of brain metastases

    PubMed Central

    Serres, Sébastien; Soto, Manuel Sarmiento; Hamilton, Alastair; McAteer, Martina A.; Carbonell, W. Shawn; Robson, Matthew D.; Ansorge, Olaf; Khrapitchev, Alexandre; Bristow, Claire; Balathasan, Lukxmi; Weissensteiner, Thomas; Anthony, Daniel C.; Choudhury, Robin P.; Muschel, Ruth J.; Sibson, Nicola R.

    2012-01-01

    Metastasis to the brain is a leading cause of cancer mortality. The current diagnostic method of gadolinium-enhanced MRI is sensitive only to larger tumors, when therapeutic options are limited. Earlier detection of brain metastases is critical for improved treatment. We have developed a targeted MRI contrast agent based on microparticles of iron oxide that enables imaging of endothelial vascular cell adhesion molecule-1 (VCAM-1). Our objectives here were to determine whether VCAM-1 is up-regulated on vessels associated with brain metastases, and if so, whether VCAM-1–targeted MRI enables early detection of these tumors. Early up-regulation of cerebrovascular VCAM-1 expression was evident on tumor-associated vessels in two separate murine models of brain metastasis. Metastases were detectable in vivo using VCAM-1–targeted MRI 5 d after induction (<1,000 cells). At clinical imaging resolutions, this finding is likely to translate to detection at tumor volumes two to three orders of magnitude smaller (0.3–3 × 105 cells) than those volumes detectable clinically (107–108 cells). VCAM-1 expression detected by MRI increased significantly (P < 0.0001) with tumor progression, and tumors showed no gadolinium enhancement. Importantly, expression of VCAM-1 was shown in human brain tissue containing both established metastases and micrometastases. Translation of this approach to the clinic could increase therapeutic options and change clinical management in a substantial number of cancer patients. PMID:22451897

  5. Determining Microvascular Obstruction and Infarct Size with Steady-State Free Precession Imaging Cardiac MRI

    PubMed Central

    Wuest, Wolfgang; Lell, Michael; May, Matthias; Scharf, Michael; Schlundt, Christian; Achenbach, Stephan; Uder, Michael; Schmid, Axel

    2015-01-01

    Purpose In cardiac MRI (cMRI) injection of contrast medium may be performed prior to the acquisition of cine steady-state free precession (SSFP) imaging to speed up the protocol and avoid delay before late Gadolinium enhancement (LGE) imaging. Aim of this study was to evaluate whether a condensed clinical protocol with contrast cine SSFP imaging is able to detect early microvascular obstruction (MO) and determine the infarct size compared to the findings of LGE inversion recovery sequences. Materials and Methods The study complies with the Declaration of Helsinki and was performed following approval by the ethic committee of the University of Erlangen-Nuremberg. Written informed consent was obtained from every patient. 68 consecutive patients (14 females/54 males) with acute ST-elevation myocardial infarction (STEMI) treated by percutaneous coronary revascularization were included in this study. CMRI was performed 6.6±2 days after symptom onset and MO and infarct size in early contrast SSFP cine imaging were compared to LGE imaging. Results MO was detected in 47/68 (69%) patients on cine SSFP and in 41/68 (60%) patients on LGE imaging. In 6 patients MO was found on cine SSFP imaging but was not detectable on LGE imaging. Infarct size on cine SSFP showed a strong agreement to LGE imaging (intraclass correlation coefficient [ICC] of 0.96 for enddiastolic, p<0.001 and 0.96 for endsystolic, p<0.001 respectively). Significant interobserver agreement was found measuring enddiastolic and endsystolic infarct size on cine SSFP imaging (p<0.01). Conclusions In patients after STEMI infarct size and presence of MO can be detected with contrast cine SSFP imaging. This could be an option in patients who are limited in their ability to comply with the demands of a cMRI protocol. PMID:25793609

  6. Adaptive Changes in Early and Late Blind: A fMRI Study of Verb Generation to Heard Nouns

    PubMed Central

    BURTON, H.; SNYDER, A. Z.; DIAMOND, J. B.; RAICHLE, M. E.

    2013-01-01

    Literacy for blind people requires learning Braille. Along with others, we have shown that reading Braille activates visual cortex. This includes striate cortex (V1), i.e., banks of calcarine sulcus, and several higher visual areas in lingual, fusiform, cuneus, lateral occipital, inferior temporal, and middle temporal gyri. The spatial extent and magnitude of magnetic resonance (MR) signals in visual cortex is greatest for those who became blind early in life. Individuals who lost sight as adults, and subsequently learned Braille, still exhibited activity in some of the same visual cortex regions, especially V1. These findings suggest these visual cortex regions become adapted to processing tactile information and that this cross-modal neural change might support Braille literacy. Here we tested the alternative hypothesis that these regions directly respond to linguistic aspects of a task. Accordingly, language task performance by blind persons should activate the same visual cortex regions regardless of input modality. Specifically, visual cortex activity in blind people ought to arise during a language task involving heard words. Eight early blind, six late blind, and eight sighted subjects were studied using functional magnetic resonance imaging (fMRI) during covert generation of verbs to heard nouns. The control task was passive listening to indecipherable sounds (reverse words) matched to the nouns in sound intensity, duration, and spectral content. Functional responses were analyzed at the level of individual subjects using methods based on the general linear model and at the group level, using voxel based ANOVA and t-test analyses. Blind and sighted subjects showed comparable activation of language areas in left inferior frontal, dorsolateral prefrontal, and left posterior superior temporal gyri. The main distinction was bilateral, left dominant activation of the same visual cortex regions previously noted with Braille reading in all blind subjects. The

  7. Grey matter volume increase following electroconvulsive therapy in patients with late life depression: a longitudinal MRI study

    PubMed Central

    Bouckaert, Filip; De Winter, François-Laurent; Emsell, Louise; Dols, Annemieke; Rhebergen, Didi; Wampers, Martien; Sunaert, Stefan; Stek, Max; Sienaert, Pascal; Vandenbulcke, Mathieu

    2016-01-01

    Background The evidence on the mechanisms of action of electroconvulsive therapy (ECT) has grown over the past decades. Recent studies show an ECT-related increase in hippocampal, amygdala and subgenual cortex volume. We examined grey matter volume changes following ECT using voxel-based morphometry (VBM) whole brain analysis in patients with severe late life depression (LLD). Methods Elderly patients with unipolar depression were treated twice weekly with right unilateral ECT until remission on the Montgomery–Åsberg Depression Rating Scale (MADRS) was achieved. Cognition (Mini Mental State Examination) and psychomotor changes (CORE Assessment) were monitored at baseline and 1 week after the last session of ECT. We performed 3 T structural MRI at both time points. We used the VBM8 toolbox in SPM8 to study grey matter volume changes. Paired t tests were used to compare pre- and post-ECT grey matter volume (voxel-level family-wise error threshold p < 0.05) and to assess clinical response. Results Twenty-eight patients (mean age 71.9 ± 7.8 yr, 8 men) participated in our study. Patients received a mean of 11.2 ± 4 sessions of ECT. The remission rate was 78.6%. Cognition, psychomotor agitation and psychomotor retardation improved significantly (p < 0.001). Right- hemispheric grey matter volume was increased in the caudate nucleus, medial temporal lobe (including hippocampus and amygdala), insula and posterior superior temporal regions but did not correlate with MADRS score. Grey matter volume increase in the caudate nucleus region correlated significantly with total CORE Assessment score (r = 0.63; p < 0.001). Limitations Not all participants were medication-free. Conclusion Electroconvulsive therapy in patients with LLD is associated with significant grey matter volume increase, which is most pronounced ipsilateral to the stimulation side. PMID:26395813

  8. A cross-linguistic evaluation of script-specific effects on fMRI lateralization in late second language readers.

    PubMed

    Koyama, Maki S; Stein, John F; Stoodley, Catherine J; Hansen, Peter C

    2014-01-01

    Behavioral and neuroimaging studies have provided evidence that reading is strongly left lateralized, and the degree of this pattern of functional lateralization can be indicative of reading competence. However, it remains unclear whether functional lateralization differs between the first (L1) and second (L2) languages in bilingual L2 readers. This question is particularly important when the particular script, or orthography, learned by the L2 readers is markedly different from their L1 script. In this study, we quantified functional lateralization in brain regions involved in visual word recognition for participants' L1 and L2 scripts, with a particular focus on the effects of L1-L2 script differences in the visual complexity and orthographic depth of the script. Two different groups of late L2 learners participated in an fMRI experiment using a visual one-back matching task: L1 readers of Japanese who learnt to read alphabetic English and L1 readers of English who learnt to read both Japanese syllabic Kana and logographic Kanji. The results showed weaker leftward lateralization in the posterior lateral occipital complex (pLOC) for logographic Kanji compared with syllabic and alphabetic scripts in both L1 and L2 readers of Kanji. When both L1 and L2 scripts were non-logographic, where symbols are mapped onto sounds, functional lateralization did not significantly differ between L1 and L2 scripts in any region, in any group. Our findings indicate that weaker leftward lateralization for logographic reading reflects greater requirement of the right hemisphere for processing visually complex logographic Kanji symbols, irrespective of whether Kanji is the readers' L1 or L2, rather than characterizing additional cognitive efforts of L2 readers. Finally, brain-behavior analysis revealed that functional lateralization for L2 visual word processing predicted L2 reading competency. PMID:24795604

  9. Correlation between MRI and Operative Findings in Bell's Palsy and Ramsay Hunt Syndrome

    PubMed Central

    Kim, In Sup; Shin, Seung-Ho; Kim, Jinna; Lee, Won-Sang

    2007-01-01

    Purpose To investigate the correlation between gadolinium enhanced magnetic resonance image (MRI) results and surgical findings of facial nerves in Bell's palsy and Ramsay Hunt syndrome. Materials and Methods From 1995 to 2004, MRI was performed on 13 patients with Bell's palsy or Ramsay Hunt syndrome, who were offered with surgical decompression of the facial nerve through the middle cranial fossa approach. Gadolinium enhanced MRI was performed on all patients and the enhancement of the facial nerve was evaluated by radiology specialists. Operative findings including the degree of the facial nerve segment swelling were examined. Furthermore, the time interval from the onset of palsy to surgery was evaluated. Results Swelling of facial nerve segments was found in patients with enhanced facial nerves from MRI. The swelling of the facial nerve in the labyrinthine segment in particular was identified in all patients with enhanced labyrinthine segments in MRI. The intraoperative swelling of geniculate ganglion of facial nerve was found in 78% of patients with enhanced facial segment in MRI (p = 0.01). The intraoperative swelling of tympanic segment was observed from fourth to ninth weeks after the onset of palsy. Conclusion MRI enhancement of facial nerves in Bell's palsy and Ramsay Hunt syndrome is associated with the extent of intratemporal lesions of facial nerves, especially in the labyrinthine segment. PMID:18159587

  10. Right ventricular dysfunction: an independent and incremental predictor of cardiac deaths late after acute myocardial infarction.

    PubMed

    Di Bella, Gianluca; Siciliano, Valeria; Aquaro, Giovanni D; De Marchi, Daniele; Rovai, Daniele; Carerj, Scipione; Molinaro, Sabrina; Lombardi, Massimo; Pingitore, Alessandro

    2015-02-01

    Prognostic implication of right ventricular dysfunction and infarction scar in the chronic phase of the myocardial infarction has been little analyzed. In 299 consecutive patients (age 63 ± 11 years) with >3 months old myocardial infarction, we quantified right and left ventricular volumes and ejection fractions by cine cardiac magnetic resonance, and right and left ventricular scar tissue by late gadolinium enhancement. During follow-up (median, 2.4 years) cardiac events (cardiac-related deaths or appropriate intra-cardiac defibrillator shocks) occurred in 21 patients. Right ventricular systolic dysfunction (ejection fraction lower the reference mean values-2 SD) was present in 67 patients (22 %), right ventricular late gadolinium enhancement was observed in 15 patients (5 %). After adjustment for left ventricular end-diastolic volume, wall motion score index, and global extent of late gadolinium enhancement, right ventricular dysfunction was an independent and incremental predictor of cardiac events (p = 0.0053), while right ventricular scar tissue extent was not. Right ventricular dysfunction is an independent and incremental predictor of cardiac events also in the chronic phase of the myocardial infarction. In these patients, right ventricular dysfunction does not necessarily mean right ventricular infarction scar, but likely reflects the effects of hemodynamic and biohumoral factors. PMID:25348657

  11. Accuracy of prediction of infarct-related arrhythmic circuits from image-based models reconstructed from low and high resolution MRI.

    PubMed

    Deng, Dongdong; Arevalo, Hermenegild; Pashakhanloo, Farhad; Prakosa, Adityo; Ashikaga, Hiroshi; McVeigh, Elliot; Halperin, Henry; Trayanova, Natalia

    2015-01-01

    Identification of optimal ablation sites in hearts with infarct-related ventricular tachycardia (VT) remains difficult to achieve with the current catheter-based mapping techniques. Limitations arise from the ambiguities in determining the reentrant pathways location(s). The goal of this study was to develop experimentally validated, individualized computer models of infarcted swine hearts, reconstructed from high-resolution ex-vivo MRI and to examine the accuracy of the reentrant circuit location prediction when models of the same hearts are instead reconstructed from low clinical-resolution MRI scans. To achieve this goal, we utilized retrospective data obtained from four pigs ~10 weeks post infarction that underwent VT induction via programmed stimulation and epicardial activation mapping via a multielectrode epicardial sock. After the experiment, high-resolution ex-vivo MRI with late gadolinium enhancement was acquired. The Hi-res images were downsampled into two lower resolutions (Med-res and Low-res) in order to replicate image quality obtainable in the clinic. The images were segmented and models were reconstructed from the three image stacks for each pig heart. VT induction similar to what was performed in the experiment was simulated. Results of the reconstructions showed that the geometry of the ventricles including the infarct could be accurately obtained from Med-res and Low-res images. Simulation results demonstrated that induced VTs in the Med-res and Low-res models were located close to those in Hi-res models. Importantly, all models, regardless of image resolution, accurately predicted the VT morphology and circuit location induced in the experiment. These results demonstrate that MRI-based computer models of hearts with ischemic cardiomyopathy could provide a unique opportunity to predict and analyze VT resulting for from specific infarct architecture, and thus may assist in clinical decisions to identify and ablate the reentrant circuit(s). PMID

  12. MRI and FDG PET/CT imaging manifestations of cardiac sarcoidosis.

    PubMed

    Lu, Yang; Sweiss, Nadera J

    2015-12-01

    A 52-year-old man had biopsy-proven sarcoidosis of mediastinal lymph nodes. Cardiac sarcoidosis was confirmed on cardiac MRI with typical imaging features as delayed gadolinium enhancement. Follow-up FDG PET/CT with a 3-day pretest diet modification showed suppression of overall myocardial uptake of FDG but with multifocal abnormal FDG uptake in the myocardium regions corresponding to the previous MRI findings. Additional noncardiac active sarcoidosis involving multiple organ and lymph nodes were also visualized on FDG PET/CT. PMID:26544904

  13. Contribution of plexus MRI in the diagnosis of atypical chronic inflammatory demyelinating polyneuropathies.

    PubMed

    Lozeron, Pierre; Lacour, Marie-Christine; Vandendries, Christophe; Théaudin, Marie; Cauquil, Cécile; Denier, Christian; Lacroix, Catherine; Adams, David

    2016-01-15

    Nerve enlargement has early been recognized in CIDP and plexus MRI hypertrophy has been reported in typical CIDP cases. Our aim is to determine plexus MRI value in the diagnosis of CIDP with an initial atypical presentation, which, up to now, has not been demonstrated. Retrospective study of 33 consecutive patients suspected of CIDP. Plexus MRI was performed on the most affected territory (brachial or lumbar). Were assessed: plexus trophicity, T2-STIR signal intensity and gadolinium enhancement. Final CIDP diagnosis was made after comprehensive workup. A histo-radiological correlation was performed. Final CIDP diagnosis was made in 25 (76%) including 21 with initial atypical clinical presentation. Eleven CIDP patients (52%) with initial atypical clinical presentation had abnormal plexus MRI including 9 suggestive of CIDP (43%) and none of the patients with an alternative diagnosis. Hypertrophy of the proximal plexus and/or extraforaminal roots was found in 8 cases and Gadolinium enhancement in 2 cases. Abnormalities were more frequent on brachial (86%) than lumbosacral MRIs (29%) and asymmetrical (72%) and most often associated with histological signs of demyelination. The nerve biopsy was suggestive of CIDP in 9/13 patients with normal MRI. Plexus MRI seems useful in the diagnostic strategy of patients with suspicion of CIDP with atypical presentation. Nerve biopsy remains important when other investigations are inconclusive. PMID:26723995

  14. Clinical and pathophysiological clues of respiratory dysfunction in late-onset Pompe disease: New insights from a comparative study by MRI and respiratory function assessment.

    PubMed

    Gaeta, Michele; Musumeci, Olimpia; Mondello, Stefania; Ruggeri, Paolo; Montagnese, Federica; Cucinotta, Maria; Vinci, Sergio; Milardi, Demetrio; Toscano, Antonio

    2015-11-01

    Respiratory insufficiency commonly develops in patients with Late Onset Pompe Disease (LOPD). It is conceivable that a timely starting of enzyme replacement therapy could avoid this life-threatening complication. Respiratory function in LOPD is commonly evaluated with standard pulmonary tests which do not extensively provide an accurate definition of the muscular pathophysiology. In eleven patients with LOPD and five healthy subjects, we compared pulmonary function results with MRI data, based on scans of the right lung acquired on maximum expiration and inspiration. We observed that variations in the cranio-caudal lung height and of lung areas in inspiration and expiration (lung delta) as well as the area of diaphragmatic movement strongly correlated with pulmonary function results. Moreover, MRI data confirmed that development of respiratory insufficiency in LOPD is mainly due to the diaphragmatic weakness with sparing of the antero-posterior chest expansion related to the activity of the intercostal muscles. These results suggest that respiratory muscle MRI is a quick, useful and reproducible tool for patient management as well as a reliable outcome measure for future LOPD therapeutic trials. PMID:26410244

  15. Comparing the diagnostic accuracy of contrast-enhanced computed tomographic angiography and gadolinium-enhanced magnetic resonance angiography for the assessment of hemodynamically significant transplant renal artery stenosis.

    PubMed

    Gaddikeri, Santhosh; Mitsumori, Lee; Vaidya, Sandeep; Hippe, Daniel S; Bhargava, Puneet; Dighe, Manjiri K

    2014-01-01

    To compare diagnostic accuracy of contrast-enhanced computed tomographic angiography (CTA) and gadolinium-enhanced magnetic resonance angiography (MRA) for the assessment of hemodynamically significant transplant renal artery stenosis (TRAS). After institutional review board approval, records of 27 patients with TRAS confirmed on digital subtraction angiography (DSA) were retrospectively reviewed. A total of 13 patients had MRA and 14 had CTA before DSA. Two board-certified fellowship-trained radiologists, one each from interventional radiology and body imaging blindly reviewed the DSA and CTA or MRA data, respectively. Sensitivity (SN), specificity (SP), positive predictive value, and negative predictive value of MRA and CTA were estimated using 50% stenosis as the detection threshold for significant TRAS. These parameters were compared between modalities using the Fisher exact test. Bias between MRA or CTA imaging and DSA was tested using the Wilcoxon signed-rank test. Two patients were excluded from the MRA group owing to susceptibility artifacts obscuring the TRAS. The correlation between MRA and DSA measurements of stenosis was r = 0.57 (95% CI:-0.02, 0.87; P = 0.052) and between CTA and DSA measurements was r = 0.63 (95% CI: 0.14, 0.87; P = 0.015); the difference between the 2 techniques was not significant (P = 0.7). Both imaging modalities tended to underestimate the degree of stenosis when compared with DSA. MRA group (SN and SP: 56% and 100%, respectively) and CTA group (SN and SP: 81% and 67%, respectively). There were no significant differences in detection performance between modalities (P>0.3 for all measures). We did not find that either modality had any advantage over the other in terms of measuring or detecting significant stenosis. Accordingly, MRA may be preferred over CTA after positive color Doppler ultrasound screening when not contraindicated owing to lack of ionizing radiation or nephrotoxic iodinated contrast. However, susceptibility of

  16. Radiation necrosis of the optic chiasm, optic tract, hypothalamus, and upper pons after radiotherapy for pituitary adenoma, detected by gadolinium-enhanced, T1-weighted magnetic resonance imaging: Case report

    SciTech Connect

    Tachibana, O.; Yamaguchi, N.; Yamashima, T.; Yamashita, J. )

    1990-10-01

    A 26-year-old woman was treated for a prolactin secreting pituitary adenoma by surgery and radiotherapy (5860 rads). Fourteen months later, she developed right hemiparesis and dysarthria. A T1-weighted magnetic resonance imaging scan using gadolinium contrast showed a small, enhanced lesion in the upper pons. Seven months later, she had a sudden onset of loss of vision, and radiation optic neuropathy was diagnosed. A T1-weighted magnetic resonance imaging scan showed widespread gadolinium-enhanced lesions in the optic chiasm, optic tract, and hypothalamus. Magnetic resonance imaging is indispensable for the early diagnosis of radiation necrosis, which is not visualized by radiography or computed tomography.

  17. Can Harry Potter still put a spell on us in a second language? An fMRI study on reading emotion-laden literature in late bilinguals.

    PubMed

    Hsu, Chun-Ting; Jacobs, Arthur M; Conrad, Markus

    2015-02-01

    In this fMRI study we contrasted emotional responses to literary reading in late bilinguals' first or second language. German participants with adequate English proficiency in their second language (L2) English read short text passages from Harry Potter books characterized by a "negative" or "positive" versus "neutral" emotional valence manipulation. Previous studies have suggested that given sufficient L2 proficiency, neural substrates involved in L1 versus L2 do not differ (Fabbro, 2001). On the other hand, the question of attenuated emotionality of L2 language processing is still an open debate (see Conrad, Recio, & Jacobs, 2011). Our results revealed a set of neural structures involved in the processing of emotion-laden literature, including emotion-related amygdala and a set of lateral prefrontal, anterior temporal, and temporo-parietal regions associated with discourse comprehension, high-level semantic integration, and Theory-of-Mind processing. Yet, consistent with post-scan emotion ratings of text passages, factorial fMRI analyses revealed stronger hemodynamic responses to "happy" than to "neutral" in bilateral amygdala and the left precentral cortex that were restricted to L1 reading. Furthermore, multivariate pattern analyses (MVPA) demonstrated better classifiability of differential patterns of brain activity elicited by passages of different emotional content in L1 than in L2 for the whole brain level. Overall, our results suggest that reading emotion-laden texts in our native language provides a stronger and more differentiated emotional experience than reading in a second language. PMID:25305809

  18. PET/MRI for Preoperative Planning in Patients with Soft Tissue Sarcoma: A Technical Report of Two Patients

    PubMed Central

    Loft, Annika; Jensen, Karl Erik; Daugaard, Søren; Petersen, Michael M.

    2013-01-01

    Clinical positron emission tomography (PET)/magnetic resonance imaging (MRI) acquisition protocols may improve the evaluation of soft tissue sarcomas (STS) prior to surgical planning. We examined two patients with lower extremity STS using a Siemens Biograph mMR PET/MRI scanner and the glucose analogue 18F-fluoro-deoxyglucose (FDG). We investigated clinically relevant tumor volumes and evaluated the relations to skeletal periosteum and nerve bundles. The patient scans suggest that FDG PET/MRI improved the edge detection, and invasion of tumor tissue into important adjacent anatomical structures can be evaluated. FDG PET/MRI also provided additional information compared to conventional Gadolinium enhanced MR imaging. The findings were proven by subsequent pathological examination of the resected tumor tissue. In the future, clinical FDG PET/MRI may be an important modality for preoperative planning, including radiation therapy planning in patients with STS. PMID:24368921

  19. Neuroanatomy of Alzheimer's Disease and Late-Life Depression: A Coordinate-Based Meta-Analysis of MRI Studies.

    PubMed

    Boccia, Maddalena; Acierno, Mauro; Piccardi, Laura

    2015-01-01

    Depression and cognitive impairment are both common disorders in elderly people and frequently occur together. Due to the presence of a common set of behavioral and cognitive symptoms, differential diagnosis may become arduous. Neuroimaging may offer a good tool during diagnosis. We performed a coordinate-based meta-analysis to compare gray matter changes in Alzheimer's disease (AD) and late-life depression (LLD). AD and LLD led to brain atrophy in networks only partially overlapping. Both conditions are linked to a reduction of the bilateral hippocampal volume, but AD is correlated with great atrophy in the left anterior hippocampus and bilateral posterior cingulate cortex, while LLD is correlated with great atrophy in the precuneus, superior frontal gyrus, and ventromedial frontal cortex. Present results shed some light on neural underpinnings of AD and LLD and provide new useful evidence for differential diagnosis. PMID:25869784

  20. Visual cortex activation in late-onset, Braille naive blind individuals: An fMRI study during semantic and phonological tasks with heard words

    PubMed Central

    Burton, Harold; McLaren, Donald G.

    2013-01-01

    Visual cortex activity in the blind has been shown in Braille literate people, which raise the question of whether Braille literacy influences cross-modal reorganization. We used fMRI to examine visual cortex activation during semantic and phonological tasks with auditory presentation of words in two late-onset blind individuals who lacked Braille literacy. Multiple visual cortical regions were activated in the Braille naive individuals. Positive BOLD responses were noted in lower tier visuotopic (e.g., V1, V2, VP, and V3) and several higher tier visual areas (e.g., V4v, V8, and BA 37). Activity was more extensive and cross-correlation magnitudes were greater during the semantic compared to the phonological task. These results with Braille naive individuals plausibly suggest that visual deprivation alone induces visual cortex reorganization. Cross-modal reorganization of lower tier visual areas may be recruited by developing skills in attending to selected non-visual inputs (e.g., Braille literacy, enhanced auditory skills). Such learning might strengthen remote connections with multisensory cortical areas. Of necessity, the Braille naive participants must attend to auditory stimulation for language. We hypothesize that learning to attend to non-visual inputs probably strengthens the remaining active synapses following visual deprivation, and thereby, increases cross-modal activation of lower tier visual areas when performing highly demanding non-visual tasks of which reading Braille is just one example. PMID:16198053

  1. Ferumoxytol-enhanced MRI differentiation of meningioma from dural metastases: a pilot study with immunohistochemical observations.

    PubMed

    Hamilton, Bronwyn E; Woltjer, Randall L; Prola-Netto, Joao; Nesbit, Gary M; Gahramanov, Seymur; Pham, Thao; Wagner, Jaime; Neuwelt, Edward A

    2016-09-01

    Malignant dural neoplasms are not reliably distinguished from benign dural neoplasms with contrast-enhanced magnetic resonance imaging (MRI). MRI enhancement in central nervous system (CNS) diseases imaged with ferumoxytol has been attributed to intracellular uptake in macrophages rather than vascular leakage. We compared imaging to histopathology and immunohistochemistry in meningiomas and dural metastases having ferumoxytol-enhanced MRI (FeMRI) and gadolinium-enhanced MRI (GdMRI) in order to correlate enhancement patterns to macrophage presence and vascular state. All patients having extraaxial CNS tumors were retrospectively selected from one of two ongoing FeMRI studies. Enhancement was compared between GdMRI and FeMRI. Diagnoses were confirmed histologically and/or by characteristic imaging. Tumor and vascular histology was reviewed. Immunohistochemical staining for CD68 (a macrophage marker), Connexin-43 (Cx43) (a marker of normal gap junctions), and smooth muscle actin (SMA) as a marker of vascularity, was performed in seven study cases with available tissue. Immunohistochemistry was performed on archival material from 33 subjects outside of the current study as controls: 20 WHO grade I cases of meningioma and 13 metastatic tumors. Metastases displayed marked delayed enhancement on FeMRI, similar to GdMRI. Four patients with dural metastases and one patient with meningioma showed similar enhancement on FeMRI and GdMRI. Five meningiomas with typical enhancement on GdMRI lacked enhancement on FeMRI. Enhancement on FeMRI was better associated with decreased Cx43 expression than intralesional macrophages. These pilot data suggest that FeMRI may better differentiate metastatic disease from meningiomas than GdMRI, and that differences in tumor vasculature rather than macrophage presence could underlie differences in contrast enhancement. PMID:27393348

  2. Delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) of hip joint cartilage in femoroacetabular impingement (FAI): Are pre- and postcontrast imaging both necessary?

    PubMed

    Bittersohl, Bernd; Hosalkar, Harish S; Kim, Young-Jo; Werlen, Stefan; Siebenrock, Klaus A; Mamisch, Tallal C

    2009-12-01

    The purpose of this study was to assess if delayed gadolinium MRI of cartilage using postcontrast T(1) (T(1Gd)) is sufficient for evaluating cartilage damage in femoroacetabular impingement without using noncontrast values (T(10)). T(1Gd) and DeltaR(1) (1/T(1Gd) - 1/T(10)) that include noncontrast T(1) measurements were studied in two grades of osteoarthritis and in a control group of asymptomatic young-adult volunteers. Differences between T(1Gd) and DeltaR(1) values for femoroacetabular impingement patients and volunteers were compared. There was a very high correlation between T(1Gd) and DeltaR(1) in all study groups. In the study cohort with Tonnis grade 0, correlation (r) was -0.95 and -0.89 with Tonnis grade 1 and -0.88 in asymptomatic volunteers, being statistically significant (P < 0.001) for all groups. For both T(1Gd) and DeltaR(1), a statistically significant difference was noted between patients and control group. Significant difference was also noted for both T(1Gd) and DeltaR(1) between the patients with Tonnis grade 0 osteoarthritis and those with grade 1 changes. Our results prove a linear correlation between T(1Gd) and DeltaR(1), suggesting that T(1Gd) assessment is sufficient for the clinical utility of delayed gadolinium MRI of cartilage in this setting and additional time-consuming T(10) evaluation may not be needed. PMID:19859935

  3. A preliminary fMRI study of a novel self-paced written fluency task: observation of left-hemispheric activation, and increased frontal activation in late vs. early task phases

    PubMed Central

    Golestanirad, Laleh; Das, Sunit; Schweizer, Tom A.; Graham, Simon J.

    2015-01-01

    Neuropsychological tests of verbal fluency are very widely used to characterize impaired cognitive function. For clinical neuroscience studies and potential medical applications, measuring the brain activity that underlies such tests with functional magnetic resonance imaging (fMRI) is of significant interest—but a challenging proposition because overt speech can cause signal artifacts, which tend to worsen as the duration of speech tasks becomes longer. In a novel approach, we present the group brain activity of 12 subjects who performed a self-paced written version of phonemic fluency using fMRI-compatible tablet technology that recorded responses and provided task-related feedback on a projection screen display, over long-duration task blocks (60 s). As predicted, we observed robust activation in the left anterior inferior and medial frontal gyri, consistent with previously reported results of verbal fluency tasks which established the role of these areas in strategic word retrieval. In addition, the number of words produced in the late phase (last 30 s) of written phonemic fluency was significantly less (p < 0.05) than the number produced in the early phase (first 30 s). Activation during the late phase vs. the early phase was also assessed from the first 20 s and last 20 s of task performance, which eliminated the possibility that the sluggish hemodynamic response from the early phase would affect the activation estimates of the late phase. The last 20 s produced greater activation maps covering extended areas in bilateral precuneus, cuneus, middle temporal gyrus, insula, middle frontal gyrus and cingulate gyrus. Among these areas, greater activation was observed in the bilateral middle frontal gyrus (Brodmann area BA 9) and cingulate gyrus (BA 24, 32) likely as part of the initiation, maintenance, and shifting of attentional resources. Consistent with previous pertinent fMRI literature involving overt and covert verbal responses, these findings highlight

  4. Head MRI

    MedlinePlus

    ... the head; MRI - cranial; NMR - cranial; Cranial MRI; Brain MRI; MRI - brain; MRI - head ... tell your health care provider if you have: Brain aneurysm clips Certain types of artificial heart valves ...

  5. Imaging of the malignant peripheral nerve sheath tumour with emphasis οn ultrasonography: correlation with MRI.

    PubMed

    Rafailidis, Vasileios; Kaziani, Theodora; Theocharides, Costas; Papanikolaou, Athanasios; Rafailidis, Dimitrios

    2014-09-01

    Malignant peripheral nerve sheath tumours affect 0.001 % of the population. The epithelioid subtype accounts for only 5 % of them. We herein present a patient with a palpable mass on the left calf, which was investigated by ultrasonography, ultrasonographically guided fine-needle biopsy and MRI. Ultrasonography estimated the size of the tumour and evaluated its echotexture. Doppler technique detected characteristic corkscrew-type blood vessel entering in the upper pole of the mass. T1-weighted, fat-suppression and gadolinium-enhanced MRI sequences confirmed ultrasonographic findings. In conclusion, although final diagnosis was established by biopsy, ultrasonography and MRI proved complementary in the characterization of the lesion and planning of surgery. PMID:25177396

  6. Feasibility for mapping cartilage t1 relaxation times in the distal metacarpus3/metatarsus3 of thoroughbred racehorses using delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC): normal cadaver study.

    PubMed

    Carstens, Ann; Kirberger, Robert M; Velleman, Mark; Dahlberg, Leif E; Fletcher, Lizelle; Lammentausta, Eveliina

    2013-01-01

    Osteoarthritis of the metacarpo/metatarsophalangeal joints is one of the major causes of poor performance in horses. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) may be a useful technique for noninvasively quantifying articular cartilage damage in horses. The purpose of this study was to describe dGEMRIC characteristics of the distal metacarpus3/metatarsus3 (Mc3/Mt3) articular cartilage in 20 cadaver specimens collected from normal Thoroughbred horses. For each specimen, T1 relaxation time was measured from scans acquired precontrast and at 30, 60, 120, and 180 min post intraarticular injection of Gd-DTPA(2-) (dGEMRIC series). For each scan, T1 relaxation times were calculated using five regions of interest (sites 1-5) in the cartilage. For all sites, a significant decrease in T1 relaxation times occurred between precontrast scans and 30, 60, 120, and 180 min scans of the dGEMRIC series (P < 0.0001). A significant increase in T1 relaxation times occurred between 60 and 180 min and between 120 and 180 min post Gd injection for all sites. For sites 1-4, a significant increase in T1 relaxation time occurred between 30 and 180 min postinjection (P < 0.05). Sites 1-5 differed significantly among one another for all times (P < 0.0001). Findings from this cadaver study indicated that dGEMRIC using intraarticular Gd-DTPA(2-) is a feasible technique for measuring and mapping changes in T1 relaxation times in equine metacarpo/metatarsophalangeal joint cartilage. Optimal times for postcontrast scans were 60-120 min. Future studies are needed to determine whether these findings are reproducible in live horses. PMID:23551282

  7. Breast imaging with ultrasound tomography: a comparative study with MRI

    NASA Astrophysics Data System (ADS)

    Ranger, Bryan; Littrup, Peter; Duric, Neb; Li, Cuiping; Schmidt, Steven; Lupinacci, Jessica; Myc, Lukasz; Szczepanski, Amy; Rama, Olsi; Bey-Knight, Lisa

    2010-03-01

    The purpose of this study was to investigate the performance of an ultrasound tomography (UST) prototype relative to magnetic resonance (MR) for imaging overall breast anatomy and accentuating tumors relative to background tissue. The study was HIPAA compliant, approved by the Institutional Review Board, and performed after obtaining the requisite informed consent. Twenty-three patients were imaged with MR and the UST prototype. T1 weighted images with fat saturation, with and without gadolinium enhancement, were used to examine anatomical structures and tumors, while T2 weighted images were used to identify cysts. The UST scans generated sound speed, attenuation, and reflection images. A qualitative visual comparison of the MRI and UST images was then used to identify anatomical similarities. A more focused approach that involved a comparison of reported masses, lesion volumes, and breast density was used to quantify the findings from the visual assessment. Our acoustic tomography prototype imaged distributions of fibrous stroma, parenchyma, fatty tissues, and lesions in patterns similar to those seen in the MR images. The range of thresholds required to establish tumor volume equivalency between MRI and UST suggested that a universal threshold for isolating masses relative to background tissue is feasible with UST. UST has demonstrated the ability to visualize and characterize breast tissues in a manner comparable to MRI. Thresholding techniques accentuate masses relative to background anatomy, which may prove clinically useful for early cancer detection.

  8. Cardiac MRI evaluation of myocardial disease.

    PubMed

    Captur, Gabriella; Manisty, Charlotte; Moon, James C

    2016-09-15

    Cardiovascular magnetic resonance (CMR) is a key imaging technique for cardiac phenotyping with a major clinical role. It can assess advanced aspects of cardiac structure and function, scar burden and other myocardial tissue characteristics but there is new information that can now be derived. This can fill many of the gaps in our knowledge with the potential to change thinking, disease classifications and definitions as well as patient care. Established techniques such as the late gadolinium enhancement technique are now embedded in clinical care. New techniques are coming through. Myocardial tissue characterisation techniques, particularly myocardial mapping can precisely measure tissue magnetisation-T1, T2, T2* and also the extracellular volume. These change in disease. Key biological pathways are now open for scrutiny including focal fibrosis (scar) and diffuse fibrosis, inflammation, metabolism and infiltration. Other new areas to engage in where major insights are growing include detailed assessments of myocardial mechanics and performance, spectroscopy and hyperpolarised CMR. In spite of the advances, challenges remain, particularly surrounding utilisation, technical development to improve accuracy, reproducibility and deliverability, and the role of multidisciplinary research to understand the detailed pathological basis of the MR signal changes. Collectively, these new developments are galvanising CMR uptake and having a major translational impact on healthcare globally and it is steadily becoming key imaging tool. PMID:27354273

  9. Use of the functional imaging modalities, f MRI r CBV and PET FDG, alters radiation therapy 3-D treatment planning in patients with malignant gliomas

    SciTech Connect

    Fitzek, M.; Pardo, F.S.; Busierre, M.

    1995-12-31

    Malignant gliomas present one of the most difficult challenges to definitive radiation therapy, not only with respect to local control, but also with respect to clinical functional status. While tumor target volume definitions for malignant gliomas are often based on CT and conventional MRI, the functional imaging modalities, echo planar rCBV (regional cerebral blood volume mapping) and 18F-fluorodeoxyglucose PET, are more sensitive modalities for the detection of neovascularization, perhaps one of the earliest signs of glial tumor initiation and progression. In order to address the clinical utility of functional imaging in radiation therapy 3-D treatment planning, we compared tumor target volume definitions and overall dosimetry in patients either undergoing co-registration of conventional Gadolinium-enhanced MRI, or co-registration of functional imaging modalities, prior to radiation therapy 3-D treatment planning.

  10. Quantitative parametric MRI of articular cartilage: a review of progress and open challenges

    PubMed Central

    Binks, D A; Hodgson, R J; Ries, M E; Foster, R J; Smye, S W; McGonagle, D

    2013-01-01

    With increasing life expectancies and the desire to maintain active lifestyles well into old age, the impact of the debilitating disease osteoarthritis (OA) and its burden on healthcare services is mounting. Emerging regenerative therapies could deliver significant advances in the effective treatment of OA but rely upon the ability to identify the initial signs of tissue damage and will also benefit from quantitative assessment of tissue repair in vivo. Continued development in the field of quantitative MRI in recent years has seen the emergence of techniques able to probe the earliest biochemical changes linked with the onset of OA. Quantitative MRI measurements including T1, T2 and T1ρ relaxometry, diffusion weighted imaging and magnetisation transfer have been studied and linked to the macromolecular structure of cartilage. Delayed gadolinium-enhanced MRI of cartilage, sodium MRI and glycosaminoglycan chemical exchange saturation transfer techniques are sensitive to depletion of cartilage glycosaminoglycans and may allow detection of the earliest stages of OA. We review these current and emerging techniques for the diagnosis of early OA, evaluate the progress that has been made towards their implementation in the clinic and identify future challenges in the field. PMID:23407427

  11. Cartilage Repair Surgery: Outcome Evaluation by Using Noninvasive Cartilage Biomarkers Based on Quantitative MRI Techniques?

    PubMed Central

    Jungmann, Pia M.; Baum, Thomas; Bauer, Jan S.; Karampinos, Dimitrios C.; Link, Thomas M.; Li, Xiaojuan; Trattnig, Siegfried; Rummeny, Ernst J.; Woertler, Klaus; Welsch, Goetz H.

    2014-01-01

    Background. New quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as outcome measures after cartilage repair. Objective. To review the current literature on the use of quantitative MRI biomarkers for evaluation of cartilage repair at the knee and ankle. Methods. Using PubMed literature research, studies on biochemical, quantitative MR imaging of cartilage repair were identified and reviewed. Results. Quantitative MR biomarkers detect early degeneration of articular cartilage, mainly represented by an increasing water content, collagen disruption, and proteoglycan loss. Recently, feasibility of biochemical MR imaging of cartilage repair tissue and surrounding cartilage was demonstrated. Ultrastructural properties of the tissue after different repair procedures resulted in differences in imaging characteristics. T2 mapping, T1rho mapping, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), and diffusion weighted imaging (DWI) are applicable on most clinical 1.5 T and 3 T MR scanners. Currently, a standard of reference is difficult to define and knowledge is limited concerning correlation of clinical and MR findings. The lack of histological correlations complicates the identification of the exact tissue composition. Conclusions. A multimodal approach combining several quantitative MRI techniques in addition to morphological and clinical evaluation might be promising. Further investigations are required to demonstrate the potential for outcome evaluation after cartilage repair. PMID:24877139

  12. Task-based optimization of flip angle for texture analysis in MRI

    NASA Astrophysics Data System (ADS)

    Brand, Jonathan F.; Furenlid, Lars R.; Altbach, Maria I.; Galons, Jean-Phillippe; Bhattacharyya, Achyut; Sharma, Puneet; Bhattacharyya, Tulshi; Bilgin, Ali; Martin, Diego R.

    2016-03-01

    Chronic liver disease is a worldwide health problem, and hepatic fibrosis (HF) is one of the hallmarks of the disease. The current reference standard for diagnosing HF is biopsy followed by pathologist examination, however this is limited by sampling error and carries risk of complications. Pathology diagnosis of HF is based on textural change in the liver as a lobular collagen network that develops within portal triads. The scale of collagen lobules is characteristically on order of 1-5 mm, which approximates the resolution limit of in vivo gadolinium-enhanced magnetic resonance imaging in the delayed phase. We have shown that MRI of formalin fixed human ex vivo liver samples mimic the textural contrast of in vivo Gd-MRI and can be used as MRI phantoms. We have developed local texture analysis that is applied to phantom images, and the results are used to train model observers. The performance of the observer is assessed with the area-under-the-receiveroperator- characteristic curve (AUROC) as the figure of merit. To optimize the MRI pulse sequence, phantoms are scanned with multiple times at a range of flip angles. The flip angle that associated with the highest AUROC is chosen as optimal based on the task of detecting HF.

  13. Network Modeling for Functional Magnetic Resonance Imaging (fMRI) Signals during Ultra-Fast Speech Comprehension in Late-Blind Listeners

    PubMed Central

    Dietrich, Susanne; Hertrich, Ingo; Ackermann, Hermann

    2015-01-01

    In many functional magnetic resonance imaging (fMRI) studies blind humans were found to show cross-modal reorganization engaging the visual system in non-visual tasks. For example, blind people can manage to understand (synthetic) spoken language at very high speaking rates up to ca. 20 syllables/s (syl/s). FMRI data showed that hemodynamic activation within right-hemispheric primary visual cortex (V1), bilateral pulvinar (Pv), and left-hemispheric supplementary motor area (pre-SMA) covaried with their capability of ultra-fast speech (16 syllables/s) comprehension. It has been suggested that right V1 plays an important role with respect to the perception of ultra-fast speech features, particularly the detection of syllable onsets. Furthermore, left pre-SMA seems to be an interface between these syllabic representations and the frontal speech processing and working memory network. So far, little is known about the networks linking V1 to Pv, auditory cortex (A1), and (mesio-) frontal areas. Dynamic causal modeling (DCM) was applied to investigate (i) the input structure from A1 and Pv toward right V1 and (ii) output from right V1 and A1 to left pre-SMA. As concerns the input Pv was significantly connected to V1, in addition to A1, in blind participants, but not in sighted controls. Regarding the output V1 was significantly connected to pre-SMA in blind individuals, and the strength of V1-SMA connectivity correlated with the performance of ultra-fast speech comprehension. By contrast, in sighted controls, not understanding ultra-fast speech, pre-SMA did neither receive input from A1 nor V1. Taken together, right V1 might facilitate the “parsing” of the ultra-fast speech stream in blind subjects by receiving subcortical auditory input via the Pv (= secondary visual pathway) and transmitting this information toward contralateral pre-SMA. PMID:26148062

  14. Heart MRI

    MedlinePlus

    ... severe kidney problems. People have been harmed in MRI machines when they did not remove metal objects from their clothes or when metal objects were left in the room by others. MRI is most often not recommended for traumatic injuries. ...

  15. MRI Scans

    MedlinePlus

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ...

  16. Micro and Macro Pattern Analyses of fMRI Data Support Both Early and Late Interaction of Numerical and Spatial Information

    PubMed Central

    Koten, Jan Willem; Lonnemann, Jan; Willmes, Klaus; Knops, André

    2011-01-01

    Numbers and space are two semantic primitives that interact with each other. Both recruit brain regions along the dorsal pathway, notably parietal cortex. This makes parietal cortex a candidate for the origin of numerical–spatial interaction. The underlying cognitive architecture of the interaction is still under scrutiny. Two classes of explanations can be distinguished. The early interaction approach assumes that numerical and spatial information are integrated into a single representation at a semantic level. A second approach postulates independent semantic representations. Only at the stage of response selection and preparation these two streams interact. In this study we used a numerical landmark task to identify the locus of the interaction between numbers and space. While lying in an MR scanner participants decided on the smaller of two numerical intervals in a visually presented number triplet. The spatial position of the middle number was varied; hence spatial intervals were congruent or incongruent with the numerical intervals. Responses in incongruent trials were slower and less accurate than in congruent trials. By combining across-vertex correlations (micro pattern) with a cluster analysis (macro pattern) we identified large-scale networks that were devoted to number processing, eye movements, and sensory–motor functions. Using support vector classification in different regions of interest along the intraparietal sulcus, the frontal eye fields, and supplementary motor area we were able to distinguish between congruent and incongruent trials in each of the networks. We suggest that the identified networks participate in the integration of numerical and spatial information and that the exclusive assumption of either an early or a late interaction between numerical and spatial information does not do justice to the complex interaction between both dimensions. PMID:22028688

  17. Unsupervised classification of cirrhotic livers using MRI data

    NASA Astrophysics Data System (ADS)

    Lee, Gobert; Kanematsu, Masayuki; Kato, Hiroki; Kondo, Hiroshi; Zhou, Xiangrong; Hara, Takeshi; Fujita, Hiroshi; Hoshi, Hiroaki

    2008-03-01

    Cirrhosis of the liver is a chronic disease. It is characterized by the presence of widespread nodules and fibrosis in the liver which results in characteristic texture patterns. Computerized analysis of hepatic texture patterns is usually based on regions-of-interest (ROIs). However, not all ROIs are typical representatives of the disease stage of the liver from which the ROIs originated. This leads to uncertainties in the ROI labels (diseased or non-diseased). On the other hand, supervised classifiers are commonly used in determining the assignment rule. This presents a problem as the training of a supervised classifier requires the correct labels of the ROIs. The main purpose of this paper is to investigate the use of an unsupervised classifier, the k-means clustering, in classifying ROI based data. In addition, a procedure for generating a receiver operating characteristic (ROC) curve depicting the classification performance of k-means clustering is also reported. Hepatic MRI images of 44 patients (16 cirrhotic; 28 non-cirrhotic) are used in this study. The MRI data are derived from gadolinium-enhanced equilibrium phase images. For each patient, 10 ROIs selected by an experienced radiologist and 7 texture features measured on each ROI are included in the MRI data. Results of the k-means classifier are depicted using an ROC curve. The area under the curve (AUC) has a value of 0.704. This is slightly lower than but comparable to that of LDA and ANN classifiers which have values 0.781 and 0.801, respectively. Methods in constructing ROC curve in relation to k-means clustering have not been previously reported in the literature.

  18. New method for predicting estrogen receptor status utilizing breast MRI texture kinetic analysis

    NASA Astrophysics Data System (ADS)

    Chaudhury, Baishali; Hall, Lawrence O.; Goldgof, Dmitry B.; Gatenby, Robert A.; Gillies, Robert; Drukteinis, Jennifer S.

    2014-03-01

    Magnetic Resonance Imaging (MRI) of breast cancer typically shows that tumors are heterogeneous with spatial variations in blood flow and cell density. Here, we examine the potential link between clinical tumor imaging and the underlying evolutionary dynamics behind heterogeneity in the cellular expression of estrogen receptors (ER) in breast cancer. We assume, in an evolutionary environment, that ER expression will only occur in the presence of significant concentrations of estrogen, which is delivered via the blood stream. Thus, we hypothesize, the expression of ER in breast cancer cells will correlate with blood flow on gadolinium enhanced breast MRI. To test this hypothesis, we performed quantitative analysis of blood flow on dynamic contrast enhanced MRI (DCE-MRI) and correlated it with the ER status of the tumor. Here we present our analytic methods, which utilize a novel algorithm to analyze 20 volumetric DCE-MRI breast cancer tumors. The algorithm generates post initial enhancement (PIE) maps from DCE-MRI and then performs texture features extraction from the PIE map, feature selection, and finally classification of tumors into ER positive and ER negative status. The combined gray level co-occurrence matrices, gray level run length matrices and local binary pattern histogram features allow quantification of breast tumor heterogeneity. The algorithm predicted ER expression with an accuracy of 85% using a Naive Bayes classifier in leave-one-out cross-validation. Hence, we conclude that our data supports the hypothesis that imaging characteristics can, through application of evolutionary principles, provide insights into the cellular and molecular properties of cancer cells.

  19. Musculoskeletal MRI.

    PubMed

    Sage, Jaime E; Gavin, Patrick

    2016-05-01

    MRI has the unique ability to detect abnormal fluid content, and is therefore unparalleled in its role of detection, diagnosis, prognosis, treatment planning and follow-up evaluation of musculoskeletal disease. MRI in companion animals should be considered in the following circumstances: a definitive diagnosis cannot be made on radiographs; a patient is nonresponsive to medical or surgical therapy; prognostic information is desired; assessing surgical margins and traumatic and/or infectious joint and bone disease; ruling out subtle developmental or early aggressive bone lesions. The MRI features of common disorders affecting the shoulder, elbow, stifle, carpal, and tarsal joints are included in this chapter. PMID:26928749

  20. Obstetric MRI.

    PubMed

    Levine, Deborah

    2006-07-01

    Ultrasound is the imaging modality of choice for pregnant patients. However, MRI is increasingly utilized in patients in whom the sonographic diagnosis is unclear. These include maternal conditions unique to pregnancy such as ectopic pregnancy, placenta accreta, and uterine dehiscence. MRI is also being increasingly utilized in the assessment of abdominopelvic pain in pregnancy, in particular in assessment for appendicitis. Fetal MRI is performed to assess central nervous system (CNS) abnormalities and patients who are considering fetal surgery for conditions such as neural tube defects, congenital diaphragmatic hernia, and masses that obstruct the airway. In the future, functional MRI and fetal volumetry may provide additional information that can aid in our care of complicated pregnancies. PMID:16736491

  1. Heart MRI

    MedlinePlus

    ... an imaging method that uses powerful magnets and radio waves to create pictures of the heart. It does ... radiation involved in MRI. The magnetic fields and radio waves used during the scan have not been shown ...

  2. Task-based optimization of flip angle for fibrosis detection in T1-weighted MRI of liver.

    PubMed

    Brand, Jonathan F; Furenlid, Lars R; Altbach, Maria I; Galons, Jean-Philippe; Bhattacharyya, Achyut; Sharma, Puneet; Bhattacharyya, Tulshi; Bilgin, Ali; Martin, Diego R

    2016-07-01

    Chronic liver disease is a worldwide health problem, and hepatic fibrosis (HF) is one of the hallmarks of the disease. The current reference standard for diagnosing HF is biopsy followed by pathologist examination; however, this is limited by sampling error and carries a risk of complications. Pathology diagnosis of HF is based on textural change in the liver as a lobular collagen network that develops within portal triads. The scale of collagen lobules is characteristically in the order of 1 to 5 mm, which approximates the resolution limit of in vivo gadolinium-enhanced magnetic resonance imaging in the delayed phase. We use MRI of formalin-fixed human ex vivo liver samples as phantoms that mimic the textural contrast of in vivo Gd-MRI. We have developed a local texture analysis that is applied to phantom images, and the results are used to train model observers to detect HF. The performance of the observer is assessed with the area-under-the-receiver-operator-characteristic curve (AUROC) as the figure-of-merit. To optimize the MRI pulse sequence, phantoms were scanned with multiple times at a range of flip angles. The flip angle that was associated with the highest AUROC was chosen as optimal for the task of detecting HF. PMID:27446971

  3. Portable MRI

    SciTech Connect

    Espy, Michelle A.

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  4. Battlefield MRI

    SciTech Connect

    Espy, Michelle

    2015-06-01

    Magnetic Resonance Imaging is the best method for non-invasive imaging of soft tissue anatomy, saving countless lives each year. It is regarded as the gold standard for diagnosis of mild to moderate traumatic brain injuries. Furthermore, conventional MRI relies on very high, fixed strength magnetic fields (> 1.5 T) with parts-per-million homogeneity, which requires very large and expensive magnets.

  5. The effect of inflammation and its reduction on brain plasticity in multiple sclerosis: MRI evidence.

    PubMed

    Tomassini, Valentina; d'Ambrosio, Alessandro; Petsas, Nikolaos; Wise, Richard G; Sbardella, Emilia; Allen, Marek; Tona, Francesca; Fanelli, Fulvia; Foster, Catherine; Carnì, Marco; Gallo, Antonio; Pantano, Patrizia; Pozzilli, Carlo

    2016-07-01

    Brain plasticity is the basis for systems-level functional reorganization that promotes recovery in multiple sclerosis (MS). As inflammation interferes with plasticity, its pharmacological modulation may restore plasticity by promoting desired patterns of functional reorganization. Here, we tested the hypothesis that brain plasticity probed by a visuomotor adaptation task is impaired with MS inflammation and that pharmacological reduction of inflammation facilitates its restoration. MS patients were assessed twice before (sessions 1 and 2) and once after (session 3) the beginning of Interferon beta (IFN beta), using behavioural and structural MRI measures. During each session, 2 functional MRI runs of a visuomotor task, separated by 25-minutes of task practice, were performed. Within-session between-run change in task-related functional signal was our imaging marker of plasticity. During session 1, patients were compared with healthy controls. Comparison of patients' sessions 2 and 3 tested the effect of reduced inflammation on our imaging marker of plasticity. The proportion of patients with gadolinium-enhancing lesions reduced significantly during IFN beta. In session 1, patients demonstrated a greater between-run difference in functional MRI activity of secondary visual areas and cerebellum than controls. This abnormally large practice-induced signal change in visual areas, and in functionally connected posterior parietal and motor cortices, was reduced in patients in session 3 compared with 2. Our results suggest that MS inflammation alters short-term plasticity underlying motor practice. Reduction of inflammation with IFN beta is associated with a restoration of this plasticity, suggesting that modulation of inflammation may enhance recovery-oriented strategies that rely on patients' brain plasticity. Hum Brain Mapp 37:2431-2445, 2016. © 2016 Wiley Periodicals, Inc. PMID:26991559

  6. Sea urchin puncture resulting in PIP joint synovial arthritis: case report and MRI study.

    PubMed

    Liram, N; Gomori, M; Perouansky, M

    2000-01-01

    Of the 600 species of sea urchins, approximately 80 may be venomous to humans. The long spined or black sea urchin, Diadema setosum may cause damage by the breaking off of its brittle spines after they penetrate the skin. Synovitis followed by arthritis may be an unusual but apparently not a rare sequel to such injury, when implantation occurs near a joint. In this case report, osseous changes were not seen by plain x-rays. Magnetic resonance imaging (MRI) was used to expose the more salient features of both soft tissue and bone changes of black sea urchin puncture injury 30 months after penetration. In all likelihood, this type of injury may be more common than the existing literature at present suggests. It is believed to be the first reported case in this part of the world as well as the first MRI study describing this type of joint pathology. Local and systemic reactions to puncture injuries from sea urchin spines have been described previously. These may range from mild, local irritation lasting a few days to granuloma formation, infection and on occasions systemic illness. The sea urchin spines are composed of calcium carbonate with proteinaceous covering. The covering tends to cause immune reactions of variable presentation. There are only a handful of reported cases with sea urchin stings on record, none of them from the Red Sea. However, this condition is probably more common than is thought and can present difficulty in diagnosis. In this case report, the inflammation responded well to heat treatment, mobilization and manipulation of the joint in its post acute and chronic stages. As some subtle changes in soft tissues and the changes in bone were not seen either on plain x-rays or ultrasound scan, gadolinium-enhanced MRI was used to unveil the marked changes in the joint. PMID:10689244

  7. Late paternities.

    PubMed

    Cohen, Jean

    2007-06-01

    Late paternities are frequent. Very often these couples ask for medically assisted procreation. In general, it is considered that the couple should not be treated differently from the couple where the father is younger. Recent studies show a certain number of specific risks linked to the late paternities. Doctors and society do not act in the same way towards men and women: a 'sensible age' for women to no longer attempt pregnancy has been set in many countries at 42 years of age, whereas men aged 80 can benefit from IVF attempts and be reimbursed by the state or insurance companies. This is an obvious inequity. PMID:17579995

  8. Comparison of facet joint activity on 99mTc-MDP SPECT/CT with facet joint signal change on MRI with fat suppression

    PubMed Central

    Lehman, Vance T.; Murphy, Robert C.; Schenck, Louis A.; Carter, Rickey E.; Johnson, Geoffrey B.; Kotsenas, Amy L.; Morris, Jonathan M.; Nathan, Mark A.; Wald, John T.; Maus, Timothy P.

    2016-01-01

    PURPOSE We compared signal change on magnetic resonance imaging (MRI) with fat suppression and bone scan activity of lumbar facet joints to determine if these two imaging findings are correlated. METHODS We retrospectively identified all patients who underwent imaging of the lumbar spine for pain evaluation using both technetium-99m methylene disphosphonate single-photon emission computed tomography/computed tomography (99mTc-MDP SPECT/CT) and MRI with at least one fat-suppressed T2- or T1-weighted sequence with gadolinium enhancement within a 180-day interval, at our institution between 1 January 2008 and 19 February 2013. Facet joint activity on 99mTc-MDP SPECT/CT and peri-facet signal change on MRI were rated as normal or increased. Agreement between the two examination types were determined with the κ and prevalence-adjusted bias-adjusted κ (PABAK) statistics. RESULTS This study included 60 patients (28 male, 47%), with a mean age of 49±19.7 years (range, 12–93 years). The κ value indicated no agreement between 99mTc-MDP SPECT/CT and MRI (κ=−0.026; 95% confidence interval: −0.051, 0.000). The PABAK values were fair to high at each spinal level, which suggests that relatively low disease prevalence lowered the κ values. Together, the κ and PABAK values indicate that there is some degree of intermodality agreement, but that it is not consistent. CONCLUSION Overall, facet joint signal change on fat-suppressed MRI did not always correlate with increased 99mTc-MDP SPECT/CT activity. MRI and 99mTc-MDP SPECT/CT for facet joint evaluation should not be considered interchangeable examinations in clinical practice or research. PMID:27035592

  9. Leg MRI scan

    MedlinePlus

    ... imaging - leg; Magnetic resonance imaging - lower extremity; MRI - ankle; Magnetic resonance imaging - ankle; MRI - femur; MRI - leg ... or bone scan Birth defects of the leg, ankle, or foot Bone pain and fever Broken bone ...

  10. MRI Safety during Pregnancy

    MedlinePlus

    ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor wants to perform a magnetic resonance imaging (MRI) exam, there is a possibility that your ...

  11. MRI to delineate the gross tumor volume of nasopharyngeal cancers: which sequences and planes should be used?

    PubMed Central

    Popovtzer, Aron; Ibrahim, Mohannad; Tatro, Daniel; Feng, Felix Y.; Ten Haken, Randall K.; Eisbruch, Avraham

    2014-01-01

    Background Magnetic resonance imaging (MRI) has been found to be better than computed tomography for defining the extent of primary gross tumor volume (GTV) in advanced nasopharyngeal cancer. It is routinely applied for target delineation in planning radiotherapy. However, the specific MRI sequences/planes that should be used are unknown. Methods Twelve patients with nasopharyngeal cancer underwent primary GTV evaluation with gadolinium-enhanced axial T1 weighted image (T1) and T2 weighted image (T2), coronal T1, and sagittal T1 sequences. Each sequence was registered with the planning computed tomography scans. Planning target volumes (PTVs) were derived by uniform expansions of the GTVs. The volumes encompassed by the various sequences/planes, and the volumes common to all sequences/planes, were compared quantitatively and anatomically to the volume delineated by the commonly used axial T1-based dataset. Results Addition of the axial T2 sequence increased the axial T1-based GTV by 12% on average (p = 0.004), and composite evaluations that included the coronal T1 and sagittal T1 planes increased the axial T1-based GTVs by 30% on average (p = 0.003). The axial T1-based PTVs were increased by 20% by the additional sequences (p = 0.04). Each sequence/plane added unique volume extensions. The GTVs common to all the T1 planes accounted for 38% of the total volumes of all the T1 planes. Anatomically, addition of the coronal and sagittal-based GTVs extended the axial T1-based GTV caudally and cranially, notably to the base of the skull. Conclusions Adding MRI planes and sequences to the traditional axial T1 sequence yields significant quantitative and anatomically important extensions of the GTVs and PTVs. For accurate target delineation in nasopharyngeal cancer, we recommend that GTVs be outlined in all MRI sequences/planes and registered with the planning computed tomography scans. PMID:25177248

  12. Classification of cirrhotic liver in Gadolinium-enhanced MR images

    NASA Astrophysics Data System (ADS)

    Lee, Gobert; Uchiyama, Yoshikazu; Zhang, Xuejun; Kanematsu, Masayuki; Zhou, Xiangrong; Hara, Takeshi; Kato, Hiroki; Kondo, Hiroshi; Fujita, Hiroshi; Hoshi, Hiroaki

    2007-03-01

    Cirrhosis of the liver is characterized by the presence of widespread nodules and fibrosis in the liver. The fibrosis and nodules formation causes distortion of the normal liver architecture, resulting in characteristic texture patterns. Texture patterns are commonly analyzed with the use of co-occurrence matrix based features measured on regions-of-interest (ROIs). A classifier is subsequently used for the classification of cirrhotic or non-cirrhotic livers. Problem arises if the classifier employed falls into the category of supervised classifier which is a popular choice. This is because the 'true disease states' of the ROIs are required for the training of the classifier but is, generally, not available. A common approach is to adopt the 'true disease state' of the liver as the 'true disease state' of all ROIs in that liver. This paper investigates the use of a nonsupervised classifier, the k-means clustering method in classifying livers as cirrhotic or non-cirrhotic using unlabelled ROI data. A preliminary result with a sensitivity and specificity of 72% and 60%, respectively, demonstrates the feasibility of using the k-means non-supervised clustering method in generating a characteristic cluster structure that could facilitate the classification of cirrhotic and non-cirrhotic livers.

  13. Assessment of myocardial fibrosis with T1 mapping MRI.

    PubMed

    Everett, R J; Stirrat, C G; Semple, S I R; Newby, D E; Dweck, M R; Mirsadraee, S

    2016-08-01

    Myocardial fibrosis can arise from a range of pathological processes and its presence correlates with adverse clinical outcomes. Cardiac magnetic resonance (CMR) can provide a non-invasive assessment of cardiac structure, function, and tissue characteristics, which includes late gadolinium enhancement (LGE) techniques to identify focal irreversible replacement fibrosis with a high degree of accuracy and reproducibility. Importantly the presence of LGE is consistently associated with adverse outcomes in a range of common cardiac conditions; however, LGE techniques are qualitative and unable to detect diffuse myocardial fibrosis, which is an earlier form of fibrosis preceding replacement fibrosis that may be reversible. Novel T1 mapping techniques allow quantitative CMR assessment of diffuse myocardial fibrosis with the two most common measures being native T1 and extracellular volume (ECV) fraction. Native T1 differentiates normal from infarcted myocardium, is abnormal in hypertrophic cardiomyopathy, and may be particularly useful in the diagnosis of Anderson-Fabry disease and amyloidosis. ECV is a surrogate measure of the extracellular space and is equivalent to the myocardial volume of distribution of the gadolinium-based contrast medium. It is reproducible and correlates well with fibrosis on histology. ECV is abnormal in patients with cardiac failure and aortic stenosis, and is associated with functional impairment in these groups. T1 mapping techniques promise to allow earlier detection of disease, monitor disease progression, and inform prognosis; however, limitations remain. In particular, reference ranges are lacking for T1 mapping values as these are influenced by specific CMR techniques and magnetic field strength. In addition, there is significant overlap between T1 mapping values in healthy controls and most disease states, particularly using native T1, limiting the clinical application of these techniques at present. PMID:27005015

  14. Temporal course of microvascular obstruction after myocardial infarction assessed by MRI

    PubMed Central

    Abanador-Kamper, Nadine; Karamani, Vasiliki; Kamper, Lars; Brinkmann, Hilmar; Haage, Patrick; Seyfarth, Melchior

    2016-01-01

    PURPOSE We aimed to analyze the extent of microvascular obstruction (MO) after the index event compared with the follow-up at a median of three months. METHODS We identified 31 patients with MO after primary percutaneous coronary intervention of acute myocardial infarction by cardiac magnetic resonance imaging. The initial examination was performed after the index event, and 27 patients had the follow-up exam after a median of three months (interquartile range, 2–4 months). In addition, we examined 10 patients without MO after transmural myocardial infarction, as a control group. RESULTS MO disappeared in 23 of 27 patients (85%) in the follow-up and transformed into transmural late gadolinium enhancement. In patients with persistent MO, mean MO size decreased from 2.25% to 1.25%. In patients with MO, mean infarct size decreased significantly from 20.8% to 14.7% (P < 0.001). In the control group, mean infarct size decreased from 12.7% to 10.5% in the follow-up scan (P = 0.137). CONCLUSION MO is significantly reduced during the follow-up after acute myocardial infarction. PMID:26714055

  15. T2-weighted MRI of post-infarct myocardial edema in mice

    PubMed Central

    Beyers, Ronald J.; Smith, R. Scott; Xu, Yaqin; Piras, Bryan A.; Salerno, Michael; Berr, Stuart S.; Meyer, Craig H.; Kramer, Christopher M.; French, Brent A.; Epstein, Frederick H.

    2011-01-01

    T2-weighted, cardiac magnetic resonance imaging (T2w CMR) can be used to noninvasively detect and quantify the edematous region that corresponds to the area at risk (AAR) following myocardial infarction (MI). Previously, CMR has been used to examine structure and function in mice, expediting the study of genetic manipulations. To date, CMR has not been applied to imaging of post-MI AAR in mice. We developed a whole-heart, T2w CMR sequence to quantify the AAR in mouse models of ischemia and infarction. The ΔB0 and ΔB1 environment around the mouse heart at 7 T were measured, and a T2-preparation sequence suitable for these conditions was developed. Both in vivo T2w and late gadolinium enhanced CMR were performed in mice after 20-minute coronary occlusions, resulting in measurements of AAR size of 32.5 ± 3.1 (mean ± SEM) % LV mass, and MI size of 50.1 ± 6.4% AAR size. Excellent interobserver agreement and agreement with histology were also found. This T2w imaging method for mice may allow for future investigations of genetic manipulations and novel therapies affecting the AAR and salvaged myocardium following reperfused MI. PMID:21630350

  16. Resolution of abnormal cardiac MRI T2 signal following immune suppression for cardiac sarcoidosis.

    PubMed

    Crouser, Elliott D; Ruden, Emily; Julian, Mark W; Raman, Subha V

    2016-08-01

    Cardiac MR (CMR) with late gadolinium enhancement is commonly used to detect cardiac damage in the setting of cardiac sarcoidosis. The addition of T2 mapping to CMR was recently shown to enhance cardiac sarcoidosis detection and correlates with increased cardiac arrhythmia risk. This study was conducted to determine if CMR T2 abnormalities and related arrhythmias are reversible following immune suppression therapy. A retrospective study of subjects with cardiac sarcoidosis with abnormal T2 signal on baseline CMR and a follow-up CMR study at least 4 months later was conducted at The Ohio State University from 2011 to 2015. Immune suppression treated participants had a significant reduction in peak myocardial T2 value (70.0±5.5 vs 59.2±6.1 ms, pretreatment vs post-treatment; p=0.017), and 83% of immune suppression treated subjects had objective improvement in cardiac arrhythmias. Two subjects who had received inadequate immune suppression treatment experienced progression of cardiac sarcoidosis. This report indicates that abnormal CMR T2 signal represents an acute inflammatory manifestation of cardiac sarcoidosis that is potentially reversible with adequate immune suppression therapy. PMID:27354042

  17. Magnetic Resonance Imaging (MRI)

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ... Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of safe, painless testing ...

  18. Alpha-tocopherol and MRI Outcomes in Multiple Sclerosis – Association and Prediction

    PubMed Central

    Løken-Amsrud, Kristin I.; Myhr, Kjell-Morten; Bakke, Søren J.; Beiske, Antonie G.; Bjerve, Kristian S.; Bjørnarå, Bård T.; Hovdal, Harald; Lilleås, Finn; Midgard, Rune; Pedersen, Tom; Benth, Jūratė Šaltytė; Torkildsen, Øivind; Wergeland, Stig; Holmøy, Trygve

    2013-01-01

    Objective Alpha-tocopherol is the main vitamin E compound in humans, and has important antioxidative and immunomodulatory properties. The aim of this study was to study alpha-tocopherol concentrations and their relationship to disease activity in Norwegian multiple sclerosis (MS) patients. Methods Prospective cohort study in 88 relapsing-remitting MS (RRMS) patients, originally included in a randomised placebo-controlled trial of omega-3 fatty acids (the OFAMS study), before and during treatment with interferon beta. The patients were followed for two years with repeated 12 magnetic resonance imaging (MRI) scans and nine serum measurements of alpha-tocopherol. Results During interferon beta (IFNB) treatment, each 10 µmol/L increase in alpha-tocopherol reduced the odds (CI 95%) for simultaneous new T2 lesions by 36.8 (0.5–59.8) %, p = 0.048, and for combined unique activity by 35.4 (1.6–57.7) %, p = 0.042, in a hierarchical regression model. These associations were not significant prior to IFNB treatment, and were not noticeably changed by gender, age, body mass index, HLA-DRB1*15, treatment group, compliance, or the concentrations of 25-hydroxyvitamin D, retinol, neutralising antibodies against IFNB, or the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid. The corresponding odds for having new T1 gadolinium enhancing lesions two months later was reduced by 65.4 (16.5–85.7) %, p = 0.019, and for new T2 lesions by 61.0 (12.4–82.6) %, p = 0.023. Conclusion During treatment with IFNB, increasing serum concentrations of alpha-tocopherol were associated with reduced odds for simultaneous and subsequent MRI disease activity in RRMS patients. PMID:23349882

  19. Pyomyositis of Obturator Muscles: Unusual Late Presentation

    PubMed Central

    Soraganvi, Prasad Channappa; Ramakanth, R

    2013-01-01

    Introduction: Pyomyositis of obturator muscles is rare condition. Late presentation with deformities of hip misleads the clinician. Late presentation (6 weeks) of this condition has not been reported earlier. This report highlights this unusual presentation of Pyomyositis of the obturator muscles. Case Report: We are reporting a 14year old female patient presented with limp and pain in hip since 6 weeks. Her hip radiographs were unremarkable. Patient was admitted and MRI done. MRI findings were consistent with obturator pyomyositis. Diagnosis of pyomyositis confirmed by MRI and we performed percutaneous aspiration and drained about 25ml of purulent material mixed with blood. The culture grew Staphylococcus aureus. Patient received intravenous antibiotic for 1week and oral antibiotic for 2weeks. Patient was immobilized in fixed skin traction in Thomas splint for 5days, later gentle mobilization was started. Her condition improved dramatically after aspiration. A follow up MRI done at 3 weeks following aspiration revealed a significant reduction in intramuscular collection of obturator internus and obturator externus. Three weeks following aspiration patient was relieved of the pain and was able to walk normally. At 6 months follow up visit patient was asymptomatic. Conclusion: Late presentation of obturator pyomyositis is rare. We emphasise on careful examination and need for early imaging for diagnosis. Percutaneous drainage results in successful treatment. PMID:27298909

  20. Pelvis MRI scan

    MedlinePlus

    ... The table slides into the middle of the MRI machine. Small devices, called coils, may be placed around ... anxious. Or your provider may suggest an open MRI in which the machine is not as close to the body. Before ...

  1. What Is Chest MRI?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Chest MRI? Chest MRI (magnetic resonance imaging) is a safe, noninvasive ... creates detailed pictures of the structures in your chest, such as your chest wall, heart, and blood ...

  2. Arm MRI scan

    MedlinePlus

    ... arm MRI (magnetic resonance imaging) scan uses strong magnets to create pictures of the upper and lower ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  3. Breast MRI scan

    MedlinePlus

    ... breast MRI may be done in combination with mammography or ultrasound . It is not a replacement for mammography. ... breast screening with MRI as an adjunct to mammography. CA Cancer J Clin . 2007;57:75-89. ...

  4. Lumbar MRI scan

    MedlinePlus

    ... resonance imaging (MRI) scan uses energy from strong magnets to create pictures of the lower part of ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  5. MRI in cranial tuberculosis.

    PubMed

    Just, M; Higer, H P; Betting, O; Bockenheimer, S; Pfannenstiel, P

    1987-11-01

    A case of multiple intracranial tuberculomas is presented. CT and MRI findings are discussed and compared. MRI showed multiple tuberculomas characterised by the same signal intensity as the surrounding brain parenchyma. Differentiation could be achieved only by the perifocal oedema of high signal intensity. Changes of the lesions during chemotherapy were monitored by CT and MRI and the results are presented. PMID:3691545

  6. Effect of in ovo immobilization on development of chick hind-limb articular cartilage: an evaluation using micro-MRI measurement of delayed gadolinium uptake.

    PubMed

    Sawamura, Chigusa; Takahashi, Masaya; McCarthy, Kathryn J; Shen, Zhenxin; Fukai, Naomi; Rodriguez, Edward K; Snyder, Brian D

    2006-12-01

    To examine the effect of immobilization on the development of articular cartilage, we assessed glycosaminoglycan (GAG) content in the chick articular surface by delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Chick embryos were paralyzed by decamethonium bromide (DMB) from day 10 to either day 13 or day 16. The GAG content of the chick knee was compared with that of nonparalyzed chick embryos. Histologic analysis was unable to quantify GAG content; however, dGEMRIC demonstrated that GAG content was higher in the femoral condyles of the nonparalyzed embryos on day 13, and on day 16 the GAG content was lower in both the femoral condyles and the tibial plateaus of the nonparalyzed embryos. These results suggest that paralysis delays embryonic hind-limb development. Osteoblastic activity at the cartilage canal, as demonstrated by staining for alkaline phosphatase (ALP), was present only in the nonparalyzed chick embryos on day 16. The GAG content of the cartilage decreased when the cartilage canals began to form on day 16. The effect of immobilization on hind-limb development was indicated by the differences in the GAG content of the cartilage anlage measured by dGEMRIC in the developing knee joint of paralyzed and nonparalyzed embryonic chicks. PMID:17089363

  7. MRI of the shoulder

    SciTech Connect

    Zlatkin, M.B.; Iannotti, J.P.; Schnall, M.D.

    1991-01-01

    This book reports on the use of magnetic resonance imaging (MRI) in evaluating shoulder disorders. The book gives detailed information on MRI techniques and shoulder anatomy, describes and illustrates MRI findings for a wide range of shoulder disorders, and explains how abnormalities seen on MIR images relate to pathophysiology and clinical signs. Special attention is given to imaging of rotator cuff disease and shoulder instability conditions for which MRI is the imaging procedure of choice. Complementing the text are 365 high-quality scans depicting normal shoulder anatomy and showing the wide variety of pathologic findings encountered in practice.

  8. Improved Fat Water Separation with Water Selective Inversion Pulse for Inversion Recovery Imaging in Cardiac MRI

    PubMed Central

    Havla, Lukas; Basha, Tamer; Rayatzadeh, Hussein; Shaw, Jaime L.; Manning, Warren J.; Reeder, Scott B.; Kozerke, Sebastian; Nezafat, Reza

    2012-01-01

    Purpose To develop an improved chemical shift-based water-fat separation sequence using a water-selective inversion pulse for inversion-recovery 3D contrast-enhanced cardiac MR. Materials and Methods In inversion-recovery sequences, the fat signal is substantially reduced due to the application of a non-selective inversion pulse. Therefore, for simultaneous visualization of water, fat, and myocardial enhancement in inversion-recovery based sequences such as late Gadolinium enhancement imaging, two separate scans are used. To overcome this, the non-selective inversion pulse is replaced with a water-selective inversion pulse. Imaging was performed in phantoms, 9 healthy subjects and 9 patients with suspected arrhythmogenic right ventricular cardiomyopathy plus 1 patient for tumor/mass imaging. In patients, images with conventional turbo-spin echo (TSE) with and without fat saturation were acquired prior to contrast injection for fat assessment. Subjective image scores (1=poor, 4=excellent) were used for image assessment. Results Phantom experiments showed a fat SNR increase between 1.7 to 5.9 times for inversion times of 150 and 300ms, respectively. The water-selective inversion pulse retains the fat signal in contrast-enhanced cardiac MR, allowing improved visualization of fat in the water-fat separated images of healthy subjects with a score of 3.7 ± 0.6. Patient images acquired with the proposed sequence were scored higher when compared with TSE sequence (3.5 ± 0.7 vs. 2.2 ± 0.5, p<0.05). Conclusion The water-selective inversion pulse retains the fat signal in inversion-recovery based contrast-enhanced cardiac MR, allowing simultaneous visualization of water and fat. PMID:22927327

  9. Regression to the Mean and Predictors of MRI Disease Activity in RRMS Placebo Cohorts - Is There a Place for Baseline-to-Treatment Studies in MS?

    PubMed Central

    Stellmann, Jan-Patrick; Stürner, Klarissa Hanja; Young, Kim Lea; Siemonsen, Susanne; Friede, Tim; Heesen, Christoph

    2015-01-01

    Background Gadolinium-enhancing (GD+) lesions and T2 lesions are MRI outcomes for phase-2 treatment trials in relapsing-remitting Multiple Sclerosis (RRMS). Little is known about predictors of lesion development and regression-to-the-mean, which is an important aspect in early baseline-to-treatment trials. Objectives To quantify regression-to-the-mean and identify predictors of MRI lesion development in placebo cohorts. Methods 21 Phase-2 and Phase-3 trials were identified by a systematic literature research. Random-effects meta-analyses were performed to estimate development of T2 and GD+ after 6 months (phase-2) or 2 years (phase-3). Predictors of lesion development were evaluated with mixed-effect meta-regression. Results The mean number of GD+-lesions per scan was similar after 6 months (1.19, 95%CI: 0.87-1.51) and 2 years (1.19, 95%CI: 1.00-1.39). 39% of the patients were without new T2-lesion after 6 month and 19% after 2 years (95%CI: 12-25%). Mean number of baseline GD+-lesions was the best predictor for new lesions after 6 months. Conclusion Baseline GD-enhancing lesions predict evolution of Gd- and T2 lesions after 6 months and might be used to control for regression to the mean effects. Overall, proof-of-concept studies with a baseline to treatment design have to face a regression to 1.2 GD+lesions per scan within 6 months. PMID:25659100

  10. Quantitative metrics of net proliferation and invasion link biological aggressiveness assessed by MRI with hypoxia assessed by FMISO-PET in newly diagnosed glioblastomas.

    PubMed

    Szeto, Mindy D; Chakraborty, Gargi; Hadley, Jennifer; Rockne, Russ; Muzi, Mark; Alvord, Ellsworth C; Krohn, Kenneth A; Spence, Alexander M; Swanson, Kristin R

    2009-05-15

    Glioblastoma multiforme (GBM) are aggressive and uniformly fatal primary brain tumors characterized by their diffuse invasion of the normal-appearing parenchyma peripheral to the clinical imaging abnormality. Hypoxia, a hallmark of aggressive tumor behavior often noted in GBMs, has been associated with resistance to therapy, poorer survival, and more malignant tumor phenotypes. Based on the existence of a set of novel imaging techniques and modeling tools, our objective was to assess a hypothesized quantitative link between tumor growth kinetics [assessed via mathematical models and routine magnetic resonance imaging (MRI)] and the hypoxic burden of the tumor [assessed via positron emission tomography (PET) imaging]. Our biomathematical model for glioma kinetics describes the spatial and temporal evolution of a glioma in terms of concentration of malignant tumor cells. This model has already been proven useful as a novel tool to dynamically quantify the net rates of proliferation (rho) and invasion (D) of the glioma cells in individual patients. Estimates of these kinetic rates can be calculated from routinely available pretreatment MRI in vivo. Eleven adults with GBM were imaged preoperatively with (18)F-fluoromisonidazole (FMISO)-PET and serial gadolinium-enhanced T1- and T2-weighted MRIs to allow the estimation of patient-specific net rates of proliferation (rho) and invasion (D). Hypoxic volumes were quantified from each FMISO-PET scan following standard techniques. To control for tumor size variability, two measures of hypoxic burden were considered: relative hypoxia (RH), defined as the ratio of the hypoxic volume to the T2-defined tumor volume, and the mean intensity on FMISO-PET scaled to the blood activity of the tracer (mean T/B). Pearson correlations between RH and the net rate of cell proliferation (rho) reached significance (P < 0.04). Moreover, highly significant positive correlations were found between biological aggressiveness ratio (rho/D) and both

  11. Implantable medical devices MRI safe.

    PubMed

    Dal Molin, Renzo; Hecker, Bertrand

    2013-01-01

    Pacemakers, ICDs, neurostimulators like deep brain stimulator electrodes, spiral cord stimulators, insulin pumps, cochlear implants, retinal implants, hearing aids, electro cardio gram (ECG) leads, or devices in interventional MRI such as vascular guide wires or catheters are affected by MRI magnetic and electromagnetic fields. Design of MRI Safe medical devices requires computer modeling, bench testing, phantom testing, and animal studies. Implanted medical devices can be MRI unsafe, MRI conditional or MRI safe (see glossary). In the following paragraphs we will investigate how to design implanted medical devices MRI safe. PMID:23739365

  12. Associations between the properties of the cartilage matrix and findings from quantitative MRI in human osteoarthritic cartilage of the knee

    PubMed Central

    Wei, Bo; Du, Xiaotao; Liu, Jun; Mao, Fengyong; Zhang, Xiang; Liu, Shuai; Xu, Yan; Zang, Fengchao; Wang, Liming

    2015-01-01

    The aim of this study was to investigate the associations between the properties of the cartilage matrix and the results of T2 mapping and delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) in human knee osteoarthritic cartilage. Osteochondral samples were harvested from the middle part of the femoral condyle and tibial plateaus of 20 patients with knee osteoarthritis (OA) during total knee arthroplasty. Sagittal T2 mapping, T1pre, and T1Gd were performed using 7.0T magnetic resonance imaging (MRI). Gycosaminoglycan (GAG) distribution was evaluated by OARSI, collagen anisotropy was assessed by polarized light microscopy (PLM), and biochemical analyses measured water, GAG, and collagen content. Associations between properties of the cartilage matrix and T2 and ΔR1 (1/T1Gd-1/T1pre) values were explored using correlation analysis. T2 and ΔR1 values were significantly correlated with the degree of cartilage degeneration (OARSI grade; Ρ = 0.53 and 0.77). T2 values were significantly correlated with water content (r = 0.69; P < 0.001), GAG content (r = -0.43; P < 0.001), and PLM grade (r = 0.47; P < 0.001), but not with collagen content (r = -0.02; P = 0.110). ΔR1 values were significantly correlated with GAG content (r = -0.84; P < 0.001) and PLM grade (r = 0.41; P < 0.001). Taken together, T2 mapping and dGEMRIC results were correlated with the properties of the cartilage matrix in human knee osteoarthritic cartilage. Combination T2 mapping and dGEMRIC represents a potential non-invasive monitoring technique to detect the progress of knee OA. PMID:26097577

  13. In vitro determination of biomechanical properties of human articular cartilage in osteoarthritis using multi-parametric MRI

    NASA Astrophysics Data System (ADS)

    Juras, Vladimir; Bittsansky, Michal; Majdisova, Zuzana; Szomolanyi, Pavol; Sulzbacher, Irene; Gäbler, Stefan; Stampfl, Jürgen; Schüller, Georg; Trattnig, Siegfried

    2009-03-01

    The objective of this study was to evaluate the correlations between MR parameters and the biomechanical properties of naturally degenerated human articular cartilage. Human cartilage explants from the femoral condyles of patients who underwent total knee replacement were evaluated on a micro-imaging system at 3 T. To quantify glycosaminoglycan (GAG) content, delayed gadolinium-enhanced MRI of the cartilage (dGEMRIC) was used. T2 maps were created by using multi-echo, multi-slice spin echo sequences with six echoes: 15, 30, 45, 60, 75, and 90 ms. Data for apparent diffusion constant (ADC) maps were obtained from pulsed gradient spin echo (PGSE) sequences with five b-values: 10.472, 220.0, 627.0, 452.8, 724.5, and 957.7. MR parameters were correlated with mechanical parameters (instantaneous ( I) and equilibrium ( Eq) modulus and relaxation time ( τ)), and the OA stage of each cartilage specimen was determined by histological evaluation of hematoxylin-eosin stained slices. For some parameters, a high correlation was found: the correlation of T1Gd vs Eq ( r = 0.8095), T1Gd vs I/ Eq ( r = -0.8441) and T1Gd vs τ ( r = 0.8469). The correlation of T2 and ADC with selected biomechanical parameters was not statistically significant. In conclusion, GAG content measured by dGEMRIC is highly related to the selected biomechanical properties of naturally degenerated articular cartilage. In contrast, T2 and ADC were unable to estimate these properties. The results of the study imply that some MR parameters can non-invasively predict the biomechanical properties of degenerated articular cartilage.

  14. Towards MRI microarrays.

    PubMed

    Hall, Andrew; Mundell, Victoria J; Blanco-Andujar, Cristina; Bencsik, Martin; McHale, Glen; Newton, Michael I; Cave, Gareth W V

    2010-04-14

    Superparamagnetic iron oxide nanometre scale particles have been utilised as contrast agents to image staked target binding oligonucleotide arrays using MRI to correlate the signal intensity and T(2)* relaxation times in different NMR fluids. PMID:20379545

  15. Sinus MRI scan

    MedlinePlus

    ... Thomsen HS, Reimer P. Intravascular contrast media for radiology, CT, and MRI. In: Adam A, Dixon AK, ... JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. New ...

  16. Knee MRI scan

    MedlinePlus

    ... magnetic resonance imaging) scan uses energy from strong magnets to create pictures of the knee joint and ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  17. Leg MRI scan

    MedlinePlus

    ... resonance imaging) scan of the leg uses strong magnets to create pictures of the leg. This may ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  18. Cervical MRI scan

    MedlinePlus

    ... magnetic resonance imaging) scan uses energy from strong magnets to create pictures of the part of the ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  19. Lumbar MRI scan

    MedlinePlus

    ... may need a lumbar MRI if you have: Low back pain that does not get better after treatment Leg ... spine Injury or trauma to the lower spine Low back pain and a history or signs of cancer Multiple ...

  20. MRI (Magnetic Resonance Imaging)

    MedlinePlus

    ... some MRI exams, intravenous (IV) drugs, such as gadolinium-based contrast agents (GBCAs) are used to change the contrast of the MR image. Gadolinium-based contrast agents are rare earth metals that ...

  1. MRI of the Breast

    MedlinePlus

    ... as a supplemental tool to breast screening with mammography or ultrasound. It may be used to screen ... following diagnosis, or further evaluate abnormalities seen on mammography. Breast MRI does not use ionizing radiation, and ...

  2. Shoulder MRI scan

    MedlinePlus

    ... an imaging test that uses energy from powerful magnets and to create pictures of the shoulder area. ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed in the room ...

  3. Optogenetic Functional MRI.

    PubMed

    Lin, Peter; Fang, Zhongnan; Liu, Jia; Lee, Jin Hyung

    2016-01-01

    The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional magnetic resonance imaging (ofMRI), which is a novel technique that combines the relatively high spatial resolution of high-field fMRI with the precision of optogenetic stimulation. Fiber optics that enable delivery of specific wavelengths of light deep into the brain in vivo are implanted into regions of interest in order to specifically stimulate targeted cell types that have been genetically induced to express light-sensitive trans-membrane conductance channels, called opsins. fMRI is used to provide a non-invasive method of determining the brain's global dynamic response to optogenetic stimulation of specific neural circuits through measurement of the blood-oxygen-level-dependent (BOLD) signal, which provides an indirect measurement of neuronal activity. This protocol describes the construction of fiber optic implants, the implantation surgeries, the imaging with photostimulation and the data analysis required to successfully perform ofMRI. In summary, the precise stimulation and whole-brain monitoring ability of ofMRI are crucial factors in making ofMRI a powerful tool for the study of the connectomics of the brain in both healthy and diseased states. PMID:27167840

  4. Optogenetic Functional MRI

    PubMed Central

    Lin, Peter; Fang, Zhongnan; Liu, Jia; Lee, Jin Hyung

    2016-01-01

    The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional magnetic resonance imaging (ofMRI), which is a novel technique that combines the relatively high spatial resolution of high-field fMRI with the precision of optogenetic stimulation. Fiber optics that enable delivery of specific wavelengths of light deep into the brain in vivo are implanted into regions of interest in order to specifically stimulate targeted cell types that have been genetically induced to express light-sensitive trans-membrane conductance channels, called opsins. fMRI is used to provide a non-invasive method of determining the brain's global dynamic response to optogenetic stimulation of specific neural circuits through measurement of the blood-oxygen-level-dependent (BOLD) signal, which provides an indirect measurement of neuronal activity. This protocol describes the construction of fiber optic implants, the implantation surgeries, the imaging with photostimulation and the data analysis required to successfully perform ofMRI. In summary, the precise stimulation and whole-brain monitoring ability of ofMRI are crucial factors in making ofMRI a powerful tool for the study of the connectomics of the brain in both healthy and diseased states. PMID:27167840

  5. Neuroimaging findings in late-onset schizophrenia and bipolar disorder.

    PubMed

    Hahn, Changtae; Lim, Hyun Kook; Lee, Chang Uk

    2014-03-01

    In recent years, there has been an increasing interest in late-onset mental disorders. Among them, geriatric schizophrenia and bipolar disorder are significant health care risks and major causes of disability. We discussed whether late-onset schizophrenia (LOS) and late-onset bipolar (LOB) disorder can be a separate entity from early-onset schizophrenia (EOS) and early-onset bipolar (EOB) disorder in a subset of late-life schizophrenia or late-life bipolar disorder through neuroimaging studies. A literature search for imaging studies of LOS or LOB was performed in the PubMed database. Search terms used were "(imaging OR MRI OR CT OR SPECT OR DTI OR PET OR fMRI) AND (schizophrenia or bipolar disorder) AND late onset." Articles that were published in English before October 2013 were included. There were a few neuroimaging studies assessing whether LOS and LOB had different disease-specific neural substrates compared with EOS and EOB. These researches mainly observed volumetric differences in specific brain regions, white matter hyperintensities, diffusion tensor imaging, or functional neuroimaging to explore the differences between LOS and LOB and EOS and EOB. The aim of this review was to highlight the neural substrates involved in LOS and LOB through neuroimaging studies. The exploration of neuroanatomical markers may be the key to the understanding of underlying neurobiology in LOS and LOB. PMID:24401535

  6. Radiotherapy planning using MRI

    NASA Astrophysics Data System (ADS)

    Schmidt, Maria A.; Payne, Geoffrey S.

    2015-11-01

    The use of magnetic resonance imaging (MRI) in radiotherapy (RT) planning is rapidly expanding. We review the wide range of image contrast mechanisms available to MRI and the way they are exploited for RT planning. However a number of challenges are also considered: the requirements that MR images are acquired in the RT treatment position, that they are geometrically accurate, that effects of patient motion during the scan are minimized, that tissue markers are clearly demonstrated, that an estimate of electron density can be obtained. These issues are discussed in detail, prior to the consideration of a number of specific clinical applications. This is followed by a brief discussion on the development of real-time MRI-guided RT.

  7. MRI Catheterization in Cardiopulmonary Disease

    PubMed Central

    Rogers, Toby; Ratnayaka, Kanishka

    2014-01-01

    Diagnosis and prognostication in patients with complex cardiopulmonary disease can be a clinical challenge. A new procedure, MRI catheterization, involves invasive right-sided heart catheterization performed inside the MRI scanner using MRI instead of traditional radiographic fluoroscopic guidance. MRI catheterization combines simultaneous invasive hemodynamic and MRI functional assessment in a single radiation-free procedure. By combining both modalities, the many individual limitations of invasive catheterization and noninvasive imaging can be overcome, and additional clinical questions can be addressed. Today, MRI catheterization is a clinical reality in specialist centers in the United States and Europe. Advances in medical device design for the MRI environment will enable not only diagnostic but also interventional MRI procedures to be performed within the next few years. PMID:24394821

  8. Gadofullerene MRI contrast agents.

    PubMed

    Bolskar, Robert D

    2008-04-01

    A promising new class of MRI contrast-enhancing agents with high relaxivities is based on gadolinium-containing metallofullerenes, which are also termed gadofullerenes. Detailed study of the water-proton relaxivity properties and intermolecular nanoclustering behavior of gadofullerene derivatives has revealed valuable information about their relaxivity mechanisms and given a deeper understanding of this new class of paramagnetic contrast agent. Here, the latest findings on water-solubilized gadofullerene materials and how these findings relate to their future applications in MRI are reviewed and discussed. PMID:18373426

  9. Clinical and Radiological Presentations of Late-Onset Spondyloarthritis

    PubMed Central

    Hmamouchi, Ihsane; Bahiri, Rachid; Hajjaj-Hassouni, Najia

    2011-01-01

    The last few years have witnessed considerable progress in the diagnosis and treatment of spondyloarthritis (SpA). Tools are now available for establishing the diagnosis at an early stage, when appropriate treatment may be able to control the inflammatory process, limit the functional impairments, and improve quality of life. Late-onset SpA after the age of 50 years is uncommon. All the spondyloarthritis subgroups are represented in the elderly. Thus, late onset spondyloarthritis is underdiagnosed in favour of other inflammatory disorders that are more frequently observed in the elderly because the clinical or radiological presentations of late-onset spondyloarthritis are modified in the elderly. They deserve further attention because age population is increasing and new criteria for axial SpA including sacroiliitis detected by MRI may help the clinician with diagnosis. Specific studies evaluating the benefit/risk ratio of TNFα-blocking agents in late onset SpA patients are required. PMID:23509636

  10. REVERSIBLE CLINICAL AND MAGNETIC RESONANCE IMAGING FINDINGS IN LATE-ONSET COBALAMIN C DEFECT.

    PubMed

    Gurkas, E; Kartal, A; Aydin, K; Kucukçongar, A; Dilber, C; Ceylaner, S

    2015-01-01

    Cobalamin C (Cbl C) disease is an inborn error of intracellular cobalamin metabolism. Two distinct clinical types are defined according to the age of onset. We describe an 8 year old girl with late-onset Cbl C disease presenting with neuropsychiatric symptoms. Mutation analysis revealed homozygous c.394C>T (p.R132X) mutation in the MMACHC gene. Serial magnetic resonance imaging (MRI) before and after the treatment are provided. MRI of the brain before treatment showed bilateral patchy focal hyperintensities in the white matter and cortical atrophy. After treatment with intramuscular hydroxycobalamin, oral folinic acid, oral betaine, normalization of MRI findings can be achieved in addition to clinical improvement. We present this case to draw attention to the reversibility of clinical and MRI findings in the late onset Cbl C disease after treatment. PMID:26852513

  11. Teratoma - MRI scan (image)

    MedlinePlus

    This MRI scan shows a tumor (teratoma) at the base of the spine (seen on the left lower edge of the screen), located in the sacrum and coccyx (sacrococcygeal) area. Teratomas are present at birth and may contain hair, teeth, and other tissues.

  12. MRI driven magnetic microswimmers.

    PubMed

    Kósa, Gábor; Jakab, Péter; Székely, Gábor; Hata, Nobuhiko

    2012-02-01

    Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach. PMID:22037673

  13. High-quality breast MRI.

    PubMed

    Hendrick, R Edward

    2014-05-01

    Breast magnetic resonance imaging (MRI) demands the competing factors of high spatial resolution, good temporal resolution, high signal-to-noise ratios, and complete bilateral breast coverage. Achieving these competing factors requires modern MRI equipment with high magnetic field strength and homogeneity, high maximum gradient strength with short rise times, dedicated multichannel bilateral breast coils with prone patient positioning, and 3D (volume) gradient-echo MRI pulse sequences with short TR, short TE, high spatial resolution, and reasonably short acquisition times. This article discusses the equipment and pulse sequences needed to achieve high-quality breast MRI and summarizes requirements of the ACR Breast MRI Accreditation Program. PMID:24792656

  14. Complications in late pregnancy.

    PubMed

    Meguerdichian, David

    2012-11-01

    Complications of late pregnancy are managed infrequently in the emergency department and, thus, can pose a challenge when the emergency physician encounters acute presentations. An expert understanding of the anatomic and physiologic changes and possible complications of late pregnancy is vital to ensure proper evaluation and care for both mother and fetus. This article focuses on the late pregnancy issues that the emergency physician will face, from the bleeding and instability of abruptio placentae to the wide spectrum of complications and management strategies encountered with preterm labor. PMID:23137403

  15. Right Ventricular Cardiomyopathy Meeting the Arrhythmogenic Right Ventricular Dysplasia Revised Criteria? Don't Forget Sarcoidosis!

    PubMed Central

    Vasaturo, Sabina; Ploeg, David E.; Buitrago, Guadalupe; Zeppenfeld, Katja; Veselic-Charvat, Maud

    2015-01-01

    A 53-year-old woman was referred for ventricular fibrillation with resuscitation. A CT-angiography showed signs of a right ventricular enlargement without obvious cause. A cardiac MRI demonstrated a dilated and hypokinetic right ventricle with extensive late gadolinium enhancement. Arrhythmogenic right ventricular dysplasia (ARVD) was suspected according to the "revised ARVD task force criteria". An endomyocardial biopsy was inconclusive. The patient developed purulent pericarditis after epicardial ablation therapy and died of toxic shock syndrome. The post-mortem pathologic examination demonstrated sarcoidosis involving the heart, lungs, and thyroid gland. PMID:25995699

  16. Late magnetic resonance imaging and clinical findings in neonates with unilateral lesions on cranial ultrasound.

    PubMed

    Bouza, H; Dubowitz, L M; Rutherford, M; Cowan, F; Pennock, J M

    1994-11-01

    Twenty-two neonates (11 term and 11 preterm) with predominantly unilateral hemispheric lesions on ultrasound were re-examined clinically and by magnetic resonance imaging (MRI) at between two and nine years of age. The aim was to correlate early ultrasound and late MRI findings with the development of hemiplegia. At follow-up, five children were normal and 15 had hemiplegia, which was mild in seven and moderate in 10. The presence or absence of hemiplegia, or its severity, could not be predicted from either early ultrasound or later MRI appearances. PMID:7958513

  17. Chronic neuroborreliosis by B. garinii: an unusual case presenting with epilepsy and multifocal brain MRI lesions.

    PubMed

    Matera, Giovanni; Labate, Angelo; Quirino, Angela; Lamberti, Angelo G; BorzÃ, Giuseppe; Barreca, Giorgio S; Mumoli, Laura; Peronace, Cinzia; Giancotti, Aida; Gambardella, Antonio; FocÃ, Alfredo; Quattrone, Aldo

    2014-07-01

    Late/chronic Lyme neuroborreliosis (LNB) represents a challenging entity whose diagnosis requires a combination of clinical and laboratory findings, surrounded by much controversy. Here we describe a patient who had a peculiar form of late LNB with CNS lesions shown by magnetic resonance imaging (MRI), and epileptic seizures, etiologically diagnosed by conventional and molecular methods. The current case provides evidence that patients presenting with epileptic seizures and MRI-detected multifocal lesions, particularly when a facial palsy has also occurred, should raise the suspicion of LNB, as this diagnosis has important implications for treatment and prognosis. PMID:25180856

  18. MRI of the penis

    PubMed Central

    Kirkham, A

    2012-01-01

    MRI of the penis is an expensive test that is not always superior to clinical examination or ultrasound. However, it shows many of the important structures, and in particular the combination of tumescence from intracavernosal alprostadil, and high-resolution T2 sequences show the glans, corpora and the tunica albuginea well. In this paper we summarise the radiological anatomy and discuss the indications for MRI. For penile cancer, it may be useful in cases where the local stage is not apparent clinically. In priapism, it is an emerging technique for assessing corporal viability, and in fracture it can in most cases make the diagnosis and locate the injury. In some cases of penile fibrosis and Peyronie's disease, it may aid surgical planning, and in complex pelvic fracture may replace or augment conventional urethrography. It is an excellent investigation for the malfunctioning penile prosthesis. PMID:23118102

  19. Occupational exposure in MRI.

    PubMed

    McRobbie, D W

    2012-04-01

    This article reviews occupational exposure in clinical MRI; it specifically considers units of exposure, basic physical interactions, health effects, guideline limits, dosimetry, results of exposure surveys, calculation of induced fields and the status of the European Physical Agents Directive. Electromagnetic field exposure in MRI from the static field B(0), imaging gradients and radiofrequency transmission fields induces electric fields and currents in tissue, which are responsible for various acute sensory effects. The underlying theory and its application to the formulation of incident and induced field limits are presented. The recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Bundesministerium für Arbeit und Soziales and Institute of Electrical and Electronics Engineers limits for incident field exposure are interpreted in a manner applicable to MRI. Field measurements show that exposure from movement within the B(0) fringe field can exceed ICNIRP reference levels within 0.5 m of the bore entrance. Rate of change of field dB/dt from the imaging gradients is unlikely to exceed the new limits, although incident field limits can be exceeded for radiofrequency (RF) exposure within 0.2-0.5 m of the bore entrance. Dosimetric surveys of routine clinical practice show that staff are exposed to peak values of 42 ± 24% of B(0), with time-averaged exposures of 5.2 ± 2.8 mT for magnets in the range 0.6-4 T. Exposure to time-varying fields arising from movement within the B(0) fringe resulted in peak dB/dt of approximately 2 T s(-1). Modelling of induced electric fields from the imaging gradients shows that ICNIRP-induced field limits are unlikely to be exceeded in most situations; however, movement through the static field may still present a problem. The likely application of the limits is discussed with respect to the reformulation of the European Union (EU) directive and its possible implications for MRI. PMID:22457400

  20. [MRI in coma survivors].

    PubMed

    Tshibanda, L; Vanhaudenhuyse, A; Bruno, M A; Boly, M; Soddu, A; Laureys, S; Moonen, G

    2009-01-01

    Traumatic and non-traumatic brain injured disorders of consciousness patients are still challenging for diagnosis, prognosis, ethical and socio-economic reasons. Currently, there remains a high rate of misdiagnosis of the vegetative state (Schnakers, et al. 2009). Recent advances in MRI techniques (diffusion tensor, magnetic resonance spectroscopy and functional imaging) provide data that could improve the diagnostic and prognostic evaluation and management of these patients. PMID:20085015

  1. MRI Anatomy of Schizophrenia

    PubMed Central

    McCarley, Robert W.; Wible, Cynthia G.; Frumin, Melissa; Hirayasu, Yoshio; Levitt, James J.; Fischer, Iris A.; Shenton, Martha E.

    2010-01-01

    Structural magnetic resonance imaging (MRI) data have provided much evidence in support of our current view that schizophrenia is a brain disorder with altered brain structure, and consequently involving more than a simple disturbance in neurotransmission. This review surveys 118 peer–reviewed studies with control group from 1987 to May 1998. Most studies (81%) do not find abnormalities of whole brain/intracranial contents, while lateral ventricle enlargement is reported in 77%, and third ventricle enlargement in 67%. The temporal lobe was the brain parenchymal region with the most consistently documented abnormalities. Volume decreases were found in 62% of 37 studies of whole temporal lobe, and in 81% of 16 studies of the superior temporal gyrus (and in 100% with gray matter separately evaluated). Fully 77% of the 30 studies of the medial temporal lobe reported volume reduction in one or more of its constituent structures (hippocampus, amygdala, parahippocampal gyrus). Despite evidence for frontal lobe functional abnormalities, structural MRI investigations less consistently found abnormalities, with 55% describing volume reduction. It may be that frontal lobe volume changes are small, and near the threshold for MRI detection. The parietal and occipital lobes were much less studied; about half of the studies showed positive findings. Most studies of cortical gray matter (86%) found volume reductions were not diffuse, but more pronounced in certain areas. About two thirds of the studies of subcortical structures of thalamus, corpus callosum and basal ganglia (which tend to increase volume with typical neuroleptics), show positive findings, as do almost all (91%) studies of cavum septi pellucidi (CSP). Most data were consistent with a developmental model, but growing evidence was compatible also with progressive, neurodegenerative features, suggesting a “two– hit” model of schizophrenia, for which a cellular hypothesis is discussed. The relationship of

  2. Predicting and Monitoring Cancer Treatment Response with DW-MRI

    PubMed Central

    Thoeny, Harriet C.; Ross, Brian D.

    2010-01-01

    An imaging biomarker that would provide for an early quantitative metric of clinical treatment response in cancer patients would provide for a paradigm shift in cancer care. Currently, non-image based clinical outcome metrics include morphology, clinical and laboratory parameters however, these are obtained relatively late following treatment. Diffusion-weighted MRI (DW-MRI) holds promise for use as a cancer treatment response biomarker as it is sensitive to macromolecular and microstructural changes which can occur at the cellular level earlier than anatomical changes during therapy. Studies have shown that successful treatment of a many tumor types can be detected using DW-MRI as an early increase in the apparent diffusion coefficient (ADC) values. Additionally, low pre-treatment ADC values of various tumors are often predictive of better outcome. These capabilities, once validated, could provide for an important opportunity to individualize therapy thereby minimizing unnecessary systemic toxicity associated with ineffective therapies with the additional advantage of improving overall patient health care and associated costs. In this report, we provide a brief technical overview of DW-MRI acquisition protocols, quantitative image analysis approaches and review studies which have implemented DW-MRI for the purpose of early prediction of cancer treatment response. PMID:20575076

  3. Molecular MRI approaches to the detection of CNS inflammation.

    PubMed

    Sibson, Nicola R; Anthony, Daniel C; van Kasteren, Sander; Dickens, Alex; Perez-Balderas, Francisco; McAteer, Martina A; Choudhury, Robin P; Davis, Benjamin G

    2011-01-01

    Inflammation is a key component of many neurological diseases, yet our understanding of the contribution of these processes to tissue damage remains poor. For many such diseases, magnetic resonance imaging (MRI) has become the method of choice for clinical diagnosis. However, many of the MRI parameters that enable disease detection, such as passive contrast enhancement across a compromised blood-brain barrier, are weighted towards late-stage disease. Moreover, whilst these methods may report on disease severity, they are not able to provide information on either disease activity or the underlying molecular processes. There is a need, therefore, to develop methods that enable earlier disease detection, potentially long before clinical symptoms become apparent, together with identification of specific molecular processes that may guide specific therapy. This chapter describes the methodology for the synthesis and validation of two novel, functional MRI-detectable probes, based on microparticles of iron oxide (MPIO), which target endothelial adhesion molecules. These contrast agents enable the detection of acute brain inflammation in vivo, at a time when pathology is undetectable by conventional MRI. Such molecular MRI methods are opening new vistas for the acute diagnosis of CNS disease, together with the possibility for individually tailored therapy and earlier, more sensitive assessment of the efficacy of novel therapies. PMID:21279613

  4. MRI Findings in Neuroferritinopathy

    PubMed Central

    Ohta, Emiko; Takiyama, Yoshihisa

    2012-01-01

    Neuroferritinopathy is a neurodegenerative disease which demonstrates brain iron accumulation caused by the mutations in the ferritin light chain gene. On brain MRI in neuroferritinopathy, iron deposits are observed as low-intensity areas on T2WI and as signal loss on T2∗WI. On T2WI, hyperintense abnormalities reflecting tissue edema and gliosis are also seen. Another characteristic finding is the presence of symmetrical cystic changes in the basal ganglia, which are seen in the advanced stages of this disorder. Atrophy is sometimes noted in the cerebellar and cerebral cortices. The variety in the MRI findings is specific to neuroferritinopathy. Based on observations of an excessive iron content in patients with chronic neurologic disorders, such as Parkinson disease and Alzheimer disease, the presence of excess iron is therefore recognized as a major risk factor for neurodegenerative diseases. The future development of multimodal and advanced MRI techniques is thus expected to play an important role in accurately measuring the brain iron content and thereby further elucidating the neurodegenerative process. PMID:21808735

  5. Late-term abortion.

    PubMed

    Epner, J E; Jonas, H S; Seckinger, D L

    1998-08-26

    Recent proposed federal legislation banning certain abortion procedures, particularly intact dilatation and extraction, would modify the US Criminal Code such that physicians performing these procedures would be liable for monetary and statutory damages. Clarification of medical procedures is important because some of the procedures used to induce abortion prior to viability are identical or similar to postviability procedures. This article reviews the scientific and medical information on late-term abortion and late-term abortion techniques and includes data on the prevalence of late-term abortion, abortion-related mortality and morbidity rates, and legal issues regarding fetal viability and the balance of maternal and fetal interests. According to enacted American Medical Association (AMA) policy, the use of appropriate medical terminology is critical in defining late-term abortion procedures, particularly intact dilatation and extraction, which is a variant of but distinct from dilatation and evacuation. The AMA recommends that the intact dilatation and extraction procedure not be used unless alternative procedures pose materially greater risk to the woman and that abortions not be performed in the third trimester except in cases of serious fetal anomalies incompatible with life. Major medical societies are urged to collaborate on clinical guidelines on late-term abortion techniques and circumstances that conform to standards of good medical practice. More research on the advantages and disadvantages of specific abortion procedures would help physicians make informed choices about specific abortion procedures. Expanded ongoing data surveillance systems estimating the prevalence of abortion are also needed. PMID:9728645

  6. Sodium MRI: methods and applications.

    PubMed

    Madelin, Guillaume; Lee, Jae-Seung; Regatte, Ravinder R; Jerschow, Alexej

    2014-05-01

    Sodium NMR spectroscopy and MRI have become popular in recent years through the increased availability of high-field MRI scanners, advanced scanner hardware and improved methodology. Sodium MRI is being evaluated for stroke and tumor detection, for breast cancer studies, and for the assessment of osteoarthritis and muscle and kidney functions, to name just a few. In this article, we aim to present an up-to-date review of the theoretical background, the methodology, the challenges, limitations, and current and potential new applications of sodium MRI. PMID:24815363

  7. Sodium MRI: Methods and applications

    PubMed Central

    Madelin, Guillaume; Lee, Jae-Seung; Regatte, Ravinder R.; Jerschow, Alexej

    2014-01-01

    Sodium NMR spectroscopy and MRI have become popular in recent years through the increased availability of high-field MRI scanners, advanced scanner hardware and improved methodology. Sodium MRI is being evaluated for stroke and tumor detection, for breast cancer studies, and for the assessment of osteoarthritis and muscle and kidney functions, to name just a few. In this article, we aim to present an up-to-date review of the theoretical background, the methodology, the challenges and limitations, and current and potential new applications of sodium MRI. PMID:24815363

  8. Lateness to School Remediation Game

    ERIC Educational Resources Information Center

    Ugwuegbulam, Charles N.; Ibrahim, Haj. Naheed

    2015-01-01

    Primary and secondary school in Nigeria encourage punctuality to school yet a good number of the learners came late to school. This is especially true in the case of day students. Learners who come late to school are usually punished in one way or the other yet the lateness to school phenomenon still persist. Lateness to school behaviour affects…

  9. Late Mitochondrial Acquisition, Really?

    PubMed Central

    Degli Esposti, Mauro

    2016-01-01

    This article provides a timely critique of a recent Nature paper by Pittis and Gabaldón that has suggested a late origin of mitochondria in eukaryote evolution. It shows that the inferred ancestry of many mitochondrial proteins has been incorrectly assigned by Pittis and Gabaldón to bacteria other than the aerobic proteobacteria from which the ancestor of mitochondria originates, thereby questioning the validity of their suggestion that mitochondrial acquisition may be a late event in eukaryote evolution. The analysis and approach presented here may guide future studies to resolve the true ancestry of mitochondria. PMID:27289097

  10. Iron shielded MRI optimization

    NASA Astrophysics Data System (ADS)

    Borghi, C. A.; Fabbri, M.

    1998-09-01

    The design of the main current systems of an actively shielded and of an iron shielded MRI device for nuclear resonance imaging, is considered. The model for the analysis of the magnetic induction produced by the current system, is based on the combination of a Boundary Element technique and of the integration of two Fredholm integral equations of the first and the second kind. The equivalent current magnetization model is used for the calculation of the magnetization produced by the iron shield. High field uniformity in a spherical region inside the device, and a low stray field in the neighborhood of the device are required. In order to meet the design requirements a multi-objective global minimization problem is solved. The minimization method is based on the combination of the filled function technique and the (1+1) evolution strategy algorithm. The multi-objective problem is treated by means of a penalty method. The actively shielded MRI system results to utilize larger amount of conductor and produce higher magnetic energy than the iron shield device. On veut étudier le projet du système des courants principaux d'un MRI à écran en fer et d'un MRI à écran actif. Le modèle d'analyse du champ magnétique produit par le système de courants est basé sur la combinaison d'une technique Boundary Element et de l'intégration de deux équations intégrales de Fredholm de première et de seconde sorte. On utilise pour calculer la magnétisation produite par l'écran en fer le modèle à cou rants de magné ti sa tion équivalents. On exige une élévation uniforme du champ dans une région sphérique au cœur de l'appareil et un bas champ magnétique dispersé à proximité de l'appareil. Dans le but de répondre aux impératifs du projet, on va résoudre un problème multiobjectif de minimisation globale. On utilise une technique de minimisation obtenue par la combinaison des méthodes “Filled Function” et “(1+1) Evolution Strategy”. Le probl

  11. Occupational exposure in MRI

    PubMed Central

    Mcrobbie, D W

    2012-01-01

    This article reviews occupational exposure in clinical MRI; it specifically considers units of exposure, basic physical interactions, health effects, guideline limits, dosimetry, results of exposure surveys, calculation of induced fields and the status of the European Physical Agents Directive. Electromagnetic field exposure in MRI from the static field B0, imaging gradients and radiofrequency transmission fields induces electric fields and currents in tissue, which are responsible for various acute sensory effects. The underlying theory and its application to the formulation of incident and induced field limits are presented. The recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Bundesministerium für Arbeit und Soziales and Institute of Electrical and Electronics Engineers limits for incident field exposure are interpreted in a manner applicable to MRI. Field measurements show that exposure from movement within the B0 fringe field can exceed ICNIRP reference levels within 0.5 m of the bore entrance. Rate of change of field dB/dt from the imaging gradients is unlikely to exceed the new limits, although incident field limits can be exceeded for radiofrequency (RF) exposure within 0.2–0.5 m of the bore entrance. Dosimetric surveys of routine clinical practice show that staff are exposed to peak values of 42±24% of B0, with time-averaged exposures of 5.2±2.8 mT for magnets in the range 0.6–4 T. Exposure to time-varying fields arising from movement within the B0 fringe resulted in peak dB/dt of approximately 2 T s−1. Modelling of induced electric fields from the imaging gradients shows that ICNIRP-induced field limits are unlikely to be exceeded in most situations; however, movement through the static field may still present a problem. The likely application of the limits is discussed with respect to the reformulation of the European Union (EU) directive and its possible implications for MRI. PMID:22457400

  12. Cardiovascular MRI with ferumoxytol.

    PubMed

    Finn, J P; Nguyen, K-L; Han, F; Zhou, Z; Salusky, I; Ayad, I; Hu, P

    2016-08-01

    The practice of contrast-enhanced magnetic resonance angiography (CEMRA) has changed significantly in the span of a decade. Concerns regarding gadolinium (Gd)-associated nephrogenic systemic fibrosis in those with severely impaired renal function spurred developments in low-dose CEMRA and non-contrast MRA as well as efforts to seek alternative MR contrast agents. Originally developed for MR imaging use, ferumoxytol (an ultra-small superparamagnetic iron oxide nanoparticle), is currently approved by the US Food and Drug Administration for the treatment of iron deficiency anaemia in adults with renal disease. Since its clinical availability in 2009, there has been rising interest in the scientific and clinical use of ferumoxytol as an MR contrast agent. The unique physicochemical and pharmacokinetic properties of ferumoxytol, including its long intravascular half-life and high r1 relaxivity, support a spectrum of MRI applications beyond the scope of Gd-based contrast agents. Moreover, whereas Gd is not found in biological systems, iron is essential for normal metabolism, and nutritional iron deficiency poses major public health challenges worldwide. Once the carbohydrate shell of ferumoxytol is degraded, the elemental iron at its core is incorporated into the reticuloendothelial system. These considerations position ferumoxytol as a potential game changer in the field of CEMRA and MRI. In this paper, we aim to summarise our experience with the cardiovascular applications of ferumoxytol and provide a brief synopsis of ongoing investigations on ferumoxytol-enhanced MR applications. PMID:27221526

  13. Speaking with a Single Cerebral Hemisphere: fMRI Language Organization after Hemispherectomy in Childhood

    ERIC Educational Resources Information Center

    Liegeois, Frederique; Connelly, Alan; Baldeweg, Torsten; Vargha-Khadem, Faraneh

    2008-01-01

    Speech-related fMRI activation was examined in six hemispherectomy patients (three left LX, three right RX, four with congenital and two with late-acquired hemiplegia) operated in childhood for the relief of drug-resistant epilepsy. Although the temporal and sensorimotor pattern of activation was similar to that found in neurologically intact…

  14. Late Babylonian Astrology

    NASA Astrophysics Data System (ADS)

    Steele, John M.

    The last five centuries BC saw the development of several new forms of astrology in Babylonia. Key to these new astrological techniques was the invention of the zodiac in about 400 BC. These new forms of astrology include personal horoscopes, astral medicine, and the exploitation of geometrical relationships between the position of heavenly bodies. Several Late Babylonian astrological doctrines were later adopted within Greek astrology.

  15. Microvascular pathology in late-life depression.

    PubMed

    Santos, Micaela; Xekardaki, Aikaterini; Kövari, Enikö; Gold, Gabriel; Bouras, Constantin; Giannakopoulos, Panteleimon

    2012-11-15

    Since the era of Gaupp who introduced the concept of atheroscletic depressive disorder, the concept of late-life depression has been correlated with cerebrovascular comorbidities, microvascular lesions, frontal cortical and subcortical gray and white matter hyperintensities. The predominant neuropsychological deficits concern the domains of planning, organization and abstraction, with executive dysfunction being the predominant finding. MRI studies reveal a higher prevalence of white matter lesions in elderly patients with depression. Molecular mechanisms underlying the disease still remain unclear. Hyperhomocysteinemia has been associated with depression through its toxicity to neurons and blood vessels. Endothelial dysfunction is another possible mechanism referring to the loss of vasodilatation capacity. Inflammatory phenomena, such as increased peripheral leucocytes, elevated CRP and cytokine levels, could play a role in endothelial dysfunction. In this review we will briefly combine findings from neurobiological, epidemiological, structural and post-mortem data. A more complex model in late-life depression combining different modalities could be an elucidating approach to the disease's etiopathogeny in the future. PMID:22687957

  16. Midlife migraine and late-life parkinsonism

    PubMed Central

    Ross, G. Webster; Sigurdsson, Sigurdur; Garcia, Melissa; Gudmundsson, Larus S.; Sveinbjörnsdóttir, Sigurlaug; Wagner, Amy K.; Gudnason, Vilmundur; Launer, Lenore J.

    2014-01-01

    Objective: In the present study, we tested the hypothesis that having migraine in middle age is related to late-life parkinsonism and a related disorder, restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED). Methods: The AGES-Reykjavik cohort (born 1907–1935) has been followed since 1967. Headaches were classified based on symptoms assessed in middle age. From 2002 to 2006, 5,764 participants were reexamined to assess symptoms of parkinsonism, diagnosis of Parkinson disease (PD), family history of PD, and RLS/WED. Results: Subjects with midlife migraine, particularly migraine with aura (MA), were in later life more likely than others to report parkinsonian symptoms (odds ratio [OR]MA = 3.6 [95% CI 2.7–4.8]) and diagnosed PD (ORMA = 2.5 [95% CI 1.2–5.2]). Women with MA were more likely than others to have a parent (ORMA = 2.26 [95% CI 1.3–4.0]) or sibling (ORMA = 1.78 [95% CI 1.1–2.9]) with PD. Late-life RLS/WED was increased for headache generally. Associations were independent of cardiovascular disease and MRI-evident presumed ischemic lesions. Conclusions: These findings suggest there may be a common vulnerability to, or consequences of, migraine and multiple indicators of parkinsonism. Additional genetic and longitudinal observational studies are needed to identify candidate pathways that may account for the comorbid constellation of symptoms. PMID:25230997

  17. fMRI adaptation revisited.

    PubMed

    Larsson, Jonas; Solomon, Samuel G; Kohn, Adam

    2016-07-01

    Adaptation has been widely used in functional magnetic imaging (fMRI) studies to infer neuronal response properties in human cortex. fMRI adaptation has been criticized because of the complex relationship between fMRI adaptation effects and the multiple neuronal effects that could underlie them. Many of the longstanding concerns about fMRI adaptation have received empirical support from neurophysiological studies over the last decade. We review these studies here, and also consider neuroimaging studies that have investigated how fMRI adaptation effects are influenced by high-level perceptual processes. The results of these studies further emphasize the need to interpret fMRI adaptation results with caution, but they also provide helpful guidance for more accurate interpretation and better experimental design. In addition, we argue that rather than being used as a proxy for measurements of neuronal stimulus selectivity, fMRI adaptation may be most useful for studying population-level adaptation effects across cortical processing hierarchies. PMID:26703375

  18. MRI of plants and foods

    NASA Astrophysics Data System (ADS)

    Van As, Henk; van Duynhoven, John

    2013-04-01

    The importance and prospects for MRI as applied to intact plants and to foods are presented in view of one of humanity's most pressing concerns, the sustainable and healthy feeding of a worldwide increasing population. Intact plants and foods have in common that their functionality is determined by complex multiple length scale architectures. Intact plants have an additional level of complexity since they are living systems which critically depend on transport and signalling processes between and within tissues and organs. The combination of recent cutting-edge technical advances and integration of MRI accessible parameters has the perspective to contribute to breakthroughs in understanding complex regulatory plant performance mechanisms. In food science and technology MRI allows for quantitative multi-length scale structural assessment of food systems, non-invasive monitoring of heat and mass transport during shelf-life and processing, and for a unique view on food properties under shear. These MRI applications are powerful enablers of rationally (re)designed food formulations and processes. Limitations and bottlenecks of the present plant and food MRI methods are mainly related to short T2 values and susceptibility artefacts originating from small air spaces in tissues/materials. We envisage cross-fertilisation of solutions to overcome these hurdles in MRI applications in plants and foods. For both application areas we witness a development where MRI is moving from highly specialised equipment to mobile and downscaled versions to be used by a broad user base in the field, greenhouse, food laboratory or factory.

  19. Differential neural mechanisms for early and late prediction error detection.

    PubMed

    Malekshahi, Rahim; Seth, Anil; Papanikolaou, Amalia; Mathews, Zenon; Birbaumer, Niels; Verschure, Paul F M J; Caria, Andrea

    2016-01-01

    Emerging evidence indicates that prediction, instantiated at different perceptual levels, facilitate visual processing and enable prompt and appropriate reactions. Until now, the mechanisms underlying the effect of predictive coding at different stages of visual processing have still remained unclear. Here, we aimed to investigate early and late processing of spatial prediction violation by performing combined recordings of saccadic eye movements and fast event-related fMRI during a continuous visual detection task. Psychophysical reverse correlation analysis revealed that the degree of mismatch between current perceptual input and prior expectations is mainly processed at late rather than early stage, which is instead responsible for fast but general prediction error detection. Furthermore, our results suggest that conscious late detection of deviant stimuli is elicited by the assessment of prediction error's extent more than by prediction error per se. Functional MRI and functional connectivity data analyses indicated that higher-level brain systems interactions modulate conscious detection of prediction error through top-down processes for the analysis of its representational content, and possibly regulate subsequent adaptation of predictive models. Overall, our experimental paradigm allowed to dissect explicit from implicit behavioral and neural responses to deviant stimuli in terms of their reliance on predictive models. PMID:27079423

  20. Differential neural mechanisms for early and late prediction error detection

    PubMed Central

    Malekshahi, Rahim; Seth, Anil; Papanikolaou, Amalia; Mathews, Zenon; Birbaumer, Niels; Verschure, Paul F. M. J.; Caria, Andrea

    2016-01-01

    Emerging evidence indicates that prediction, instantiated at different perceptual levels, facilitate visual processing and enable prompt and appropriate reactions. Until now, the mechanisms underlying the effect of predictive coding at different stages of visual processing have still remained unclear. Here, we aimed to investigate early and late processing of spatial prediction violation by performing combined recordings of saccadic eye movements and fast event-related fMRI during a continuous visual detection task. Psychophysical reverse correlation analysis revealed that the degree of mismatch between current perceptual input and prior expectations is mainly processed at late rather than early stage, which is instead responsible for fast but general prediction error detection. Furthermore, our results suggest that conscious late detection of deviant stimuli is elicited by the assessment of prediction error’s extent more than by prediction error per se. Functional MRI and functional connectivity data analyses indicated that higher-level brain systems interactions modulate conscious detection of prediction error through top-down processes for the analysis of its representational content, and possibly regulate subsequent adaptation of predictive models. Overall, our experimental paradigm allowed to dissect explicit from implicit behavioral and neural responses to deviant stimuli in terms of their reliance on predictive models. PMID:27079423

  1. MRI Meets MPI: a bimodal MPI-MRI tomograph.

    PubMed

    Vogel, Patrick; Lother, Steffen; Rückert, Martin A; Kullmann, Walter H; Jakob, Peter M; Fidler, Florian; Behr, Volker C

    2014-10-01

    While magnetic particle imaging (MPI) constitutes a novel biomedical imaging technique for tracking superparamagnetic nanoparticles in vivo, unlike magnetic resonance imaging (MRI), it cannot provide anatomical background information. Until now these two modalities have been performed in separate scanners and image co-registration has been hampered by the need to reposition the sample in both systems as similarly as possible. This paper presents a bimodal MPI-MRI-tomograph that combines both modalities in a single system.MPI and MRI images can thus be acquired without moving the sample or replacing any parts in the setup. The images acquired with the presented setup show excellent agreement between the localization of the nanoparticles in MPI and the MRI background data. A combination of two highly complementary imaging modalities has been achieved. PMID:25291350

  2. Breast MRI: opportunities and challenges.

    PubMed

    Day, Deborah

    2009-12-01

    In 2007, the American Cancer Society published guidelines for using breast MRI to screen women who were at high risk for breast cancer. Although breast MRI, which is typically used as an adjunctto mammography, is highly sensitive for detecting breast cancers, its use is somewhat controversial for a number of reasons including its cost and lack of specificity. This article describes the indications for breast MRI and discusses the pros and cons of using it to screen women for cancer and evaluate the extent of disease in women who are newly diagnosed. PMID:20092173

  3. Growth Control in Colon Epithelial Cells: Gadolinium Enhances Calcium-Mediated Growth Regulation

    PubMed Central

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K.

    2013-01-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1–5 µM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet. PMID:23008064

  4. Hypoxic-ischaemic encephalopathy: early and late magnetic resonance imaging findings in relation to outcome.

    PubMed Central

    Rutherford, M; Pennock, J; Schwieso, J; Cowan, F; Dubowitz, L

    1996-01-01

    Sixteen infants with hypoxic-ischaemic encephalopathy (HIE) were studied using serial magnetic resonance imaging (MRI) up to the age of 2 years. The infants had regular neurological and developmental assessments. An nuclear magnetic resonance (NMR) score was devised to quantify the early and late MRI findings and a neurological optimality score was used to quantify abnormal neurological signs at the time of the final examination. The follow up MRI score was compared with the neonatal MRI score and the outcome of the child. There was a strong positive correlation between the neonatal and follow up MRI scores and between MRI scores and optimality score. All infants with a normal outcome had patchy white matter abnormalities. All infants with an abnormal outcome had extensive white matter abnormalities. The outcome was most severe in those infants with additional basal ganglia atrophy with or without cyst formation. Infants with mild HIE who are developmentally normal at the age of 2 years do not have normal MRI scans and may be at risk of minor neurological problems by school age. Bilateral basal ganglia abnormalities are associated with severe developmental delay, but infants with mainly white matter and cortical abnormalities have less severe problems despite extensive tissue loss. Images PMID:8976678

  5. Hypoxic-ischaemic encephalopathy: early and late magnetic resonance imaging findings in relation to outcome.

    PubMed

    Rutherford, M; Pennock, J; Schwieso, J; Cowan, F; Dubowitz, L

    1996-11-01

    Sixteen infants with hypoxic-ischaemic encephalopathy (HIE) were studied using serial magnetic resonance imaging (MRI) up to the age of 2 years. The infants had regular neurological and developmental assessments. An nuclear magnetic resonance (NMR) score was devised to quantify the early and late MRI findings and a neurological optimality score was used to quantify abnormal neurological signs at the time of the final examination. The follow up MRI score was compared with the neonatal MRI score and the outcome of the child. There was a strong positive correlation between the neonatal and follow up MRI scores and between MRI scores and optimality score. All infants with a normal outcome had patchy white matter abnormalities. All infants with an abnormal outcome had extensive white matter abnormalities. The outcome was most severe in those infants with additional basal ganglia atrophy with or without cyst formation. Infants with mild HIE who are developmentally normal at the age of 2 years do not have normal MRI scans and may be at risk of minor neurological problems by school age. Bilateral basal ganglia abnormalities are associated with severe developmental delay, but infants with mainly white matter and cortical abnormalities have less severe problems despite extensive tissue loss. PMID:8976678

  6. Late Washing efficiency

    SciTech Connect

    Morrissey, M.F.

    1992-08-31

    Interim Waste Technology has demonstrated the Late Washing concept on the Experimental Laboratory Filter (ELF) at TNX. In two tests, washing reduced the [NO{sub 2}{sup {minus}}] from 0.08 M to approximately 0.01 M on slurries with 2 year equivalent radiation exposures and 9.5 wt. % solids. For both washes, the [NO{sub 2}{sup {minus}}] decreased at rates near theoretical for a constant volume stirred vessel, indicating approximately l00% washing efficiency. Permeate flux was greater than 0.05 gpm/ft{sup 2} for both washes at a transmembrane pressure of 50 psi and flow velocity of 9 ft/sec.

  7. Late embryogenesis abundant proteins

    PubMed Central

    Olvera-Carrillo, Yadira; Reyes, José Luis

    2011-01-01

    Late Embryogenesis Abundant (LEA) proteins accumulate at the onset of seed desiccation and in response to water deficit in vegetative plant tissues. The typical LEA proteins are highly hydrophilic and intrinsically unstructured. They have been classified in different families, each one showing distinctive conserved motifs. In this manuscript we present and discuss some of the recent findings regarding their role in plant adaptation to water deficit, as well as those concerning to their possible function, and how it can be related to their intrinsic structural flexibility. PMID:21447997

  8. Scientists attack European MRI rules

    NASA Astrophysics Data System (ADS)

    Harris, Margaret

    2010-08-01

    A report by the European Science Foundation (ESF) has sharply criticized a European Union (EU) directive on electromagnetic fields, arguing that limits on workers' exposure will have "potentially disastrous" consequences for magnetic resonance imaging (MRI).

  9. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePlus Videos and Cool Tools

    ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary ...

  10. Metalloprotein-based MRI probes

    PubMed Central

    Matsumoto, Yuri; Jasanoff, Alan

    2013-01-01

    Metalloproteins have long been recognized as key determinants of endogenous contrast in magnetic resonance imaging (MRI) of biological subjects. More recently, both natural and engineered metalloproteins have been harnessed as biotechnological tools to probe gene expression, enzyme activity, and analyte concentrations by MRI. Metalloprotein MRI probes are paramagnetic and function by analogous mechanisms to conventional gadolinium or iron oxide-based MRI contrast agents. Compared with synthetic agents, metalloproteins typically offer worse sensitivity, but the possibilities of using protein engineering and targeted gene expression approaches in conjunction with metalloprotein contrast agents are powerful and sometimes definitive strengths. This review summarizes theoretical and practical aspects of metalloprotein-based contrast agents, and discusses progress in the exploitation of these proteins for molecular imaging applications. PMID:23376346

  11. BOLD MRI of the Kidneys

    PubMed Central

    Li, Lu-Ping; Halter, Sarah; Prasad, Pottumarthi V.

    2008-01-01

    Synopsis Oxygenation status plays a major role in renal physiology and pathophysiology and hence has attracted considerable attention in recent years. While much of the early work and a significant amount of present work is based on invasive methods or ex vivo analysis and hence restricted to animal models, BOLD (blood oxygen level dependent) MRI has been shown to extend these findings to humans. BOLD MRI is most useful in monitoring effects of physiological or pharmacological maneuvers. Several teams around the world have demonstrated reproducible data and have illustrated several useful applications. Studies supporting the use of renal BOLD MRI in characterizing disease with prognostic value have also been reported. Here, an overview of the current state-of-the art of renal BOLD MRI is provided. PMID:18926426

  12. MRI/MRS as a surrogate marker for clinical progression in GM1 gangliosidosis.

    PubMed

    Regier, Debra S; Kwon, Hyuk Joon; Johnston, Jean; Golas, Gretchen; Yang, Sandra; Wiggs, Edythe; Latour, Yvonne; Thomas, Sarah; Portner, Cindy; Adams, David; Vezina, Gilbert; Baker, Eva H; Tifft, Cynthia J

    2016-03-01

    Background GM1 gangliosidosis is a lysosomal storage disorder caused by mutations in GLB1, encoding β-galactosidase. The range of severity is from type I infantile disease, lethal in early childhood, to type III adult onset, resulting in gradually progressive neurological symtpoms in adulthood. The intermediate group of patients has been recently classified as having type II late infantile subtype with onset of symptoms at one to three years of age or type II juvenile subtype with symptom onset at 2-10 years. To characterize disease severity and progression, six Late infantile and nine juvenile patients were evaluated using magnetic resonance imaging (MRI), and MR spectroscopy (MRS). Since difficulties with ambulation (gross motor function) and speech (expressive language) are often the first reported symptoms in type II GM1, patients were also scored in these domains. Deterioration of expressive language and ambulation was more rapid in the late infantile patients. Fourteen MRI scans in six Late infantile patients identified progressive atrophy in the cerebrum and cerebellum. Twenty-six MRI scans in nine juvenile patients revealed greater variability in extent and progression of atrophy. Quantitative MRS demonstrated a deficit of N-acetylaspartate in both the late infantile and juvenile patients with greater in the late infantile patients. This correlates with clinical measures of ambulation and expressive language. The two subtypes of type II GM1 gangliosidosis have different clinical trajectories. MRI scoring, quantitative MRS and brain volume correlate with clinical disease progression and may serve as important minimally-invasive outcome measures for clinical trials. © 2015 Wiley Periodicals, Inc. PMID:26646981

  13. Quantitative pharmacologic MRI in mice.

    PubMed

    Perles-Barbacaru, Teodora-Adriana; Procissi, Daniel; Demyanenko, Andrey V; Jacobs, Russell E

    2012-04-01

    Pharmacologic MRI (phMRI) uses functional MRI techniques to provide a noninvasive in vivo measurement of the hemodynamic effects of drugs. The cerebral blood volume change (ΔCBV) serves as a surrogate for neuronal activity via neurovascular coupling mechanisms. By assessing the location and time course of brain activity in mouse mutant studies, phMRI can provide valuable insights into how different behavioral phenotypes are expressed in deferring brain activity response to drug challenge. In this report, we evaluate the utility of three different intravascular ultrasmall superparamagnetic iron oxide (USPIO) contrast agents for phMRI using a gradient-echo technique, with temporal resolution of one min at high magnetic field. The tissue half-life of the USPIOs was studied using a nonlinear detrending model. The three USPIOs are candidates for CBV weighted phMRI experiments, with r(2)/r(1) ratios ≥ 20 and apparent half-lives ≥ 1.5 h at the described doses. An echo-time of about 10 ms or longer results in a functional contrast to noise ratio (fCNR) > 75 after USPIO injection, with negligible decrease between 1.5-2 h. phMRI experiments were conducted at 7 T using cocaine as a psychotropic substance and acetazolamide, a global vasodilator, as a positive control. Cocaine acts as a dopamine-serotonin-norepinephrine reuptake inhibitor, increasing extracellular concentrations of these neurotransmitters, and thus increasing dopaminergic, serotonergic and noradrenergic neurotransmission. phMRI results showed that CBV was reduced in the normal mouse brain after cocaine challenge, with the largest effects in the nucleus accumbens, whereas after acetazolamide, blood volume was increased in both cerebral and extracerebral tissue. PMID:21793079

  14. Is there a place for cardiovascular magnetic resonance conditional devices in systemic inflammatory diseases?

    PubMed

    Mavrogeni, Sophie I; Poulos, George; Sfikakis, Petros P; Kitas, George D; Kolovou, Genovefa; Theodorakis, George

    2016-06-01

    Rhythm disturbances and sudden cardiac death (SCD) are important manifestations of cardiac involvement in systemic inflammatory diseases (SID). The commonest events demanding the implantation of a device include ventricular tachycardia and atrioventricular block, mainly diagnosed in sarcoidosis, systemic lupus erythematosus and scleroderma. In SCD, cardiac magnetic resonance (CMR) identified areas of late gadolinium enhancement (LGE) in 71% and provided an arrhythmic substrate in 76%, while during the follow-up, the extent of LGE identified a subgroup at increased risk for future adverse events. CMR has been successfully used for detection of cardiac disease in SID, including myocarditis, coronary, microvascular and valvular disease. Additionally, SIDs have a higher probability to need MRI scanning of other organs, due to their systemic disease. These reasons support the necessity of an MRI conditional device in SIDs. A broad selection of devices, approved for the MRI environment under defined conditions allows the safe and accurate scanning of SID patients. PMID:26878099

  15. Coaxial waveguide MRI.

    PubMed

    Alt, Stefan; Müller, Marco; Umathum, Reiner; Bolz, Armin; Bachert, Peter; Semmler, Wolfhard; Bock, Michael

    2012-04-01

    As ultrahigh-field MR imaging systems suffer from the standing wave problems of conventional coil designs, the use of antenna systems that generate travelling waves was suggested. As a modification to the original approach, we propose the use of a coaxial waveguide configuration with interrupted inner conductor. This concept can focus the radiofrequency energy to the desired imaging region in the human body and can operate at different Larmor frequencies without hardware modifications, as it is not limited by a lower cut-off frequency. We assessed the potential of the method with a hardware prototype setup that was loaded with a tissue equivalent phantom and operated with imaging areas of different size. Signal and flip angle distributions within the phantom were analyzed, and imaging at different Larmor frequencies was performed. Results were compared to a finite difference time domain simulation of the setup that additionally provides information on the spatial distribution of the specific absorption rate load. Furthermore, simulation results with a human model (virtual family) are presented. It was found that the proposed method can be used for MRI at multiple frequencies, achieving transmission efficiencies similar to other travelling wave approaches but still suffers from several limitations due to the used mode of wave propagation. PMID:22021117

  16. [Late postcontusion secondary glaucoma].

    PubMed

    Chiseliţă, D; Vancea, P; Filiman, O; Brănişteanu, D; Bredetean, M; Poiata, I

    1995-01-01

    The investigation of 33 patients with late postcontusional glaucoma subjected to surgery and followed up for 25 +/- 8.24 months has revealed: the interval accident-surgery is shorter in the close-angle combined forms; the essential mechanisms responsible for glaucoma occurrence are: the alteration of trabecular meshwork (for open-angle glaucoma) and pupillary block (for close angle glaucoma); simple cases required antiglaucoma surgery (trabeculectomy, peripheral iridectomy) and the mixed ones required combined (trabeculectomy, lens extraction, lens implant) or sequential surgeries (antiglaucoma surgery, vitrectomy etc); the glaucomatous process was stopped in 83.4% of the open-angle glaucoma cases and progressed in 23.5% of the close-angle glaucoma cases; the functional improvements post antiglaucoma surgery combined with removal of opacities are lessened by the higher frequency of severe per- and post-operative complication. PMID:7654676

  17. Functional MRI at the Crossroads

    PubMed Central

    Van Horn, John Darrell; Poldrack, Russell A.

    2009-01-01

    Since the observation of the blood oxygenation level dependent (BOLD) effect on measured MR signal in the brain, functional magnetic resonance imaging (fMRI) has rapidly become the tool of choice for exploring brain function in cognitive neuroscience. Although fMRI is an exciting and powerful means to examining the brain in vivo, the field has sometimes permitted itself to believe that patterns of BOLD activity reveal more than it is possible to measure given the method’s spatial and temporal sampling, while concurrently not fully exploring the amount of information it provides. In this article, we examine some of the constraints on the kinds of inferences that can be supported by fMRI. We critique the concept of reverse inference that is often employed to say some cognitive function must be present given activity in a specific region. We review the consideration of functional and effective connectivity that remain infrequently applied in cognitive neuroimaging, highlighting recent thinking on the ways in which functional imaging can be used to characterize inter-regional communication. Recent advances in neuroimaging that make it possible to assess anatomical connectivity using diffusion tensor imaging (DTI) and we discuss how these may inform interpretation of fMRI results. Descriptions of fMRI studies in the media, in some instances, serve to misrepresent fMRI’s capabilities. We comment on how researchers need to faithfully represent fMRI’s promise and limitations in dealing with the media. Finally, as we stand at the crossroads of fMRI research, where one pathway leads toward a rigorous understanding of cognitive operations using fMRI and another leads us to a predictable collection of observations absent of clear insight, we offer our impressions of a fruitful path for future functional imaging research. PMID:19041348

  18. [MRI-guided musculoskeletal biopsy].

    PubMed

    Daecke, W; Libicher, M; Mädler, U; Rumpf, C; Bernd, L

    2003-02-01

    MRI-guided musculoskeletal biopsy has been mentioned to be a minimally invasive method to obtain specimens for diagnostic purposes in bone tumors. To evaluate the viability, to assess the accuracy, and to record possible complications of this method, clinical data of 19 MRI-guided biopsies were analyzed. Interventions were performed on 18 patients (1-78 years) as an outpatient procedure: 15 skeletal and 4 soft tissue biopsies were taken from the pelvis, upper limb,or lower limb. We used T1-weighted gradient echoes (GE) for locating the puncture site and T2-weighted turbo spin echoes (TSE) for visualization of needle position. In 14 of 18 MRI-guided biopsies, a definite histological diagnosis was obtained. According to the pathologist, the inadequate size of the specimen was the main reason for missing the diagnoses in four cases.Long intervention time and inappropriate biopsy tools proved to be the main disadvantages of MRI-guided biopsy, but technical improvement might solve these technical problems in future.A postbiopsy hematoma was the only complication observed. Once technically improved, MRI-guided biopsy could be a precise alternative routine method for musculoskeletal biopsies in future. PMID:12607083

  19. Estimating Motion From MRI Data

    PubMed Central

    OZTURK, CENGIZHAN; DERBYSHIRE, J. ANDREW; MCVEIGH, ELLIOT R.

    2007-01-01

    Invited Paper Magnetic resonance imaging (MRI) is an ideal imaging modality to measure blood flow and tissue motion. It provides excellent contrast between soft tissues, and images can be acquired at positions and orientations freely defined by the user. From a temporal sequence of MR images, boundaries and edges of tissues can be tracked by image processing techniques. Additionally, MRI permits the source of the image signal to be manipulated. For example, temporary magnetic tags displaying a pattern of variable brightness may be placed in the object using MR saturation techniques, giving the user a known pattern to detect for motion tracking. The MRI signal is a modulated complex quantity, being derived from a rotating magnetic field in the form of an induced current. Well-defined patterns can also be introduced into the phase of the magnetization, and could be thought of as generalized tags. If the phase of each pixel is preserved during image reconstruction, relative phase shifts can be used to directly encode displacement, velocity and acceleration. New methods for modeling motion fields from MRI have now found application in cardiovascular and other soft tissue imaging. In this review, we shall describe the methods used for encoding, imaging, and modeling motion fields with MRI. PMID:18958181

  20. Environmentally responsive MRI contrast agents

    PubMed Central

    Davies, Gemma-Louise; Kramberger, Iris; Davis, Jason J.

    2015-01-01

    Biomedical imaging techniques can provide a vast amount of anatomical information, enabling diagnosis and the monitoring of disease and treatment profile. MRI uniquely offers convenient, non-invasive, high resolution tomographic imaging. A considerable amount of effort has been invested, across several decades, in the design of non toxic paramagnetic contrast agents capable of enhancing positive MRI signal contrast. Recently, focus has shifted towards the development of agents capable of specifically reporting on their local biochemical environment, where a switch in image contrast is triggered by a specific stimulus/biochemical variable. Such an ability would not only strengthen diagnosis but also provide unique disease-specific biochemical insight. This feature article focuses on recent progress in the development of MRI contrast switching with molecular, macromolecular and nanoparticle-based agents. PMID:24040650

  1. Modeling late Paleozoic glaciation

    SciTech Connect

    Crowley, T.J.; Baum, S.K. )

    1992-06-01

    Late Paleozoic glaciation on Gondwana is associated with changes in geography, solar luminosity, and estimated CO{sub 2} levels. To assess the relative importance of these boundary conditions, the authors conducted a suite of climate model simulations for the periods before, during, and after peak mid-Carboniferous ({approximately}300 Ma) glaciation (340, 300, and 255 and 225 Ma, respectively). Orbital insolation values favorable for glaciation and interglaciation were used for each time interval. Results indicate that changes in geography cause significant changes in snow area, but the temporal trend is not consistent with the geologic record for glaciation. Combined CO{sub 2}-plus-geography changes yield the best agreement with observations. In addition, interglacial orbital configurations result in almost ice-free conditions for the glacial interval at 300 Ma, at a time of low CO{sub 2}. The large simulated glacial-interglacial snowline fluctuations for Permian-Carboniferous time may explain cyclothem fluctuations at these times. Overall, results support the importance of the CO{sub 2} paradigm, but also indicate that a fuller understanding of past climate change requires consideration of paleogeographic, luminosity, and orbital insolation changes.

  2. Fetal MRI: A pictorial essay

    PubMed Central

    Rathee, Sapna; Joshi, Priscilla; Kelkar, Abhimanyu; Seth, Nagesh

    2016-01-01

    Ultrasonography (USG) is the primary method for antenatal fetal evaluation. However, fetal magnetic resonance imaging (MRI) has now become a valuable adjunct to USG in confirming/excluding suspected abnormalities and in the detection of additional abnormalities, thus changing the outcome of pregnancy and optimizing perinatal management. With the development of ultrafast sequences, fetal MRI has made remarkable progress in recent times. In this pictorial essay, we illustrate a spectrum of structural abnormalities affecting the central nervous system, thorax, genitourinary and gastrointestinal tract, as well as miscellaneous anomalies. Anomalies in twin gestations and placental abnormalities have also been included. PMID:27081224

  3. MRI EVALUATION OF KNEE CARTILAGE

    PubMed Central

    Rodrigues, Marcelo Bordalo; Camanho, Gilberto Luís

    2015-01-01

    Through the ability of magnetic resonance imaging (MRI) to characterize soft tissue noninvasively, it has become an excellent method for evaluating cartilage. The development of new and faster methods allowed increased resolution and contrast in evaluating chondral structure, with greater diagnostic accuracy. In addition, physiological techniques for cartilage assessment that can detect early changes before the appearance of cracks and erosion have been developed. In this updating article, the various techniques for chondral assessment using knee MRI will be discussed and demonstrated. PMID:27022562

  4. [MRI of the pineal gland.

    PubMed

    Langevad, Line; Madsen, Camilla Gøbel; Siebner, Hartwig; Garde, Ellen

    2014-11-10

    The pineal gland (CP) is located centrally in the brain and produces melatonin. Cysts and concrements are frequent findings on MRI but their significance is still unclear. The visualization of CP is difficult due to its location and surrounding structures and so far, no standardized method exists. New studies suggest a correlation between CP-morphology and melatonin secretion as well as a connection between melatonin, disturbed circadian rhythm, and the development of cancer and cardiovascular diseases, underlining the need for a standardized approach to CP on MRI. PMID:25394927

  5. The Raven MRI teaching file

    SciTech Connect

    Lufkin, R.B.; Bradley, W.G. Jr.; Brant-Zawadzki, M.

    1990-01-01

    This book presents individually bound guides for each section of the body, the 1,000 concise and clearly illustrated case files cover neoplastic, non-neoplastic, degenerative, inflammatory, congenital, and acquired disease of the brain, head and neck, spine, musculoskeletal system, cardiovascular system, chest, abdomen, and male and female pelvis. It focuses on specific body regions; one is devoted to pediatric MRI; and one reviews the principles of MRI and identifies frequently encountered artifacts. It contains 100 completed case studies, with high-resolution MR images.

  6. Paramagnetic lanthanide chelates for multicontrast MRI.

    PubMed

    Cakić, Nevenka; Savić, Tanja; Stricker-Shaver, Janice; Truffault, Vincent; Platas-Iglesias, Carlos; Mirkes, Christian; Pohmann, Rolf; Scheffler, Klaus; Angelovski, Goran

    2016-07-28

    The preparation of a paramagnetic chelator that serves as a platform for multicontrast MRI, and can be utilized either as a T1-weighted, paraCEST or (19)F MRI contrast agent is reported. Its europium(iii) complex exhibits an extremely slow water exchange rate which is optimal for the use in CEST MRI. The potential of this platform was demonstrated through a series of MRI studies on tube phantoms and animals. PMID:27291157

  7. Late-adult onset Leigh syndrome.

    PubMed

    McKelvie, Penelope; Infeld, Bernard; Marotta, Rosetta; Chin, Judy; Thorburn, David; Collins, Steven

    2012-02-01

    We report an illustrative case of a 74-year-old man who, in the absence of intercurrent illness, presented with rapid cognitive decline. MRI showed bilateral, symmetrical, high T2-weighted signal in the anterior basal ganglia and medial thalami, extending to the periaqueductal grey matter, basal ganglia and basal frontal lobes. A (18)F-fluorodeoxyglucose-positron emission tomography scan showed widespread reduction of metabolism in the cortex of the frontal, temporal and parietal lobes, posterior cingulate gyrus, precuneus and caudate nuclei, with sparing of the sensorimotor cortex, thalami and lentiform nuclei. A mild vitamin B12 deficiency was found and despite normal thiamine levels, intravenous (IV) thiamine and vitamin B therapy was commenced, with a short course of IV methylprednisolone and tetracycline. Repeat neuropsychological assessment four weeks following treatment revealed increased alertness and interactiveness but significant cognitive decline persisted. Unexpectedly, the patient suffered a transmural anterior myocardial infarction six weeks after presentation and died within 24hours. An a autopsy showed: global reduction in cytochrome oxidase (COX) activity in all skeletal muscles examined; bilateral, symmetrical, hypervascular, focally necrotizing lesions in the substantia nigra, periaqueductal grey matter, superior colliculi, medial thalami anteriorly and posteriorly, as well as in the putamena but the mammillary bodies were not affected. Biochemical analysis of fresh muscle confirmed selective deficiency of complex IV of the oxidative phosphorylation chain. A diagnosis of late-adult onset Leigh syndrome was made. Multiple genetic studies failed to identify the specific underlying mutation. The relevant literature is reviewed. PMID:22273117

  8. Early and Late Onset Sepsis in Late Preterm Infants

    PubMed Central

    Cohen-Wolkowiez, Michael; Moran, Cassandra; Benjamin, Daniel K.; Cotten, C. Michael; Clark, Reese H.; Benjamin, Daniel K.; Smith, P. Brian

    2009-01-01

    Background Preterm birth is increasing worldwide, and late preterm births, which comprise more than 70% of all preterm births, account for much of the increase. Early and late onset sepsis results in significant mortality in extremely preterm infants, but little is known about sepsis outcomes in late preterm infants. Methods This is an observational cohort study of infants < 121 days of age (119,130 infants less than or equal to 3 days of life and 106,142 infants between 4 and 120 days of life) with estimated gestational age at birth between 34 and 36 weeks, admitted to 248 neonatal intensive care units in the United States between 1996 and 2007. Results During the study period, the cumulative incidence of early and late onset sepsis was 4.42 and 6.30 episodes per 1000 admissions, respectively. Gram-positive organisms caused the majority of early and late onset sepsis episodes. Infants with early onset sepsis caused by Gram-negative rods and infants with late onset sepsis were more likely to die than their peers with sterile blood cultures (OR 4.39, 95% CI 1.71–11.23, P=0.002; and OR 3.37, 95% CI 2.35–4.84, P<0.001, respectively). Conclusion Late preterm infants demonstrate specific infection rates, pathogen distribution, and mortality associated with early and late onset sepsis. The results of this study are generalizable to late preterm infants admitted to the special care nursery or neonatal intensive care unit. PMID:19953725

  9. A Sensitive Period for Language in the Visual Cortex: Distinct Patterns of Plasticity in Congenitally versus Late Blind Adults

    ERIC Educational Resources Information Center

    Bedny, Marina; Pascual-Leone, Alvaro; Dravida, Swethasri; Saxe, Rebecca

    2012-01-01

    Recent evidence suggests that blindness enables visual circuits to contribute to language processing. We examined whether this dramatic functional plasticity has a sensitive period. BOLD fMRI signal was measured in congenitally blind, late blind (blindness onset 9-years-old or later) and sighted participants while they performed a sentence…

  10. fMRI Validation of fNIRS Measurements During a Naturalistic Task.

    PubMed

    Noah, J Adam; Ono, Yumie; Nomoto, Yasunori; Shimada, Sotaro; Tachibana, Atsumichi; Zhang, Xian; Bronner, Shaw; Hirsch, Joy

    2015-01-01

    We present a method to compare brain activity recorded with near-infrared spectroscopy (fNIRS) in a dance video game task to that recorded in a reduced version of the task using fMRI (functional magnetic resonance imaging). Recently, it has been shown that fNIRS can accurately record functional brain activities equivalent to those concurrently recorded with functional magnetic resonance imaging for classic psychophysical tasks and simple finger tapping paradigms. However, an often quoted benefit of fNIRS is that the technique allows for studying neural mechanisms of complex, naturalistic behaviors that are not possible using the constrained environment of fMRI. Our goal was to extend the findings of previous studies that have shown high correlation between concurrently recorded fNIRS and fMRI signals to compare neural recordings obtained in fMRI procedures to those separately obtained in naturalistic fNIRS experiments. Specifically, we developed a modified version of the dance video game Dance Dance Revolution (DDR) to be compatible with both fMRI and fNIRS imaging procedures. In this methodology we explain the modifications to the software and hardware for compatibility with each technique as well as the scanning and calibration procedures used to obtain representative results. The results of the study show a task-related increase in oxyhemoglobin in both modalities and demonstrate that it is possible to replicate the findings of fMRI using fNIRS in a naturalistic task. This technique represents a methodology to compare fMRI imaging paradigms which utilize a reduced-world environment to fNIRS in closer approximation to naturalistic, full-body activities and behaviors. Further development of this technique may apply to neurodegenerative diseases, such as Parkinson's disease, late states of dementia, or those with magnetic susceptibility which are contraindicated for fMRI scanning. PMID:26132365

  11. fMRI Validation of fNIRS Measurements During a Naturalistic Task

    PubMed Central

    Noah, J. Adam; Ono, Yumie; Nomoto, Yasunori; Shimada, Sotaro; Tachibana, Atsumichi; Zhang, Xian; Bronner, Shaw; Hirsch, Joy

    2015-01-01

    We present a method to compare brain activity recorded with near-infrared spectroscopy (fNIRS) in a dance video game task to that recorded in a reduced version of the task using fMRI (functional magnetic resonance imaging). Recently, it has been shown that fNIRS can accurately record functional brain activities equivalent to those concurrently recorded with functional magnetic resonance imaging for classic psychophysical tasks and simple finger tapping paradigms. However, an often quoted benefit of fNIRS is that the technique allows for studying neural mechanisms of complex, naturalistic behaviors that are not possible using the constrained environment of fMRI. Our goal was to extend the findings of previous studies that have shown high correlation between concurrently recorded fNIRS and fMRI signals to compare neural recordings obtained in fMRI procedures to those separately obtained in naturalistic fNIRS experiments. Specifically, we developed a modified version of the dance video game Dance Dance Revolution (DDR) to be compatible with both fMRI and fNIRS imaging procedures. In this methodology we explain the modifications to the software and hardware for compatibility with each technique as well as the scanning and calibration procedures used to obtain representative results. The results of the study show a task-related increase in oxyhemoglobin in both modalities and demonstrate that it is possible to replicate the findings of fMRI using fNIRS in a naturalistic task. This technique represents a methodology to compare fMRI imaging paradigms which utilize a reduced-world environment to fNIRS in closer approximation to naturalistic, full-body activities and behaviors. Further development of this technique may apply to neurodegenerative diseases, such as Parkinson’s disease, late states of dementia, or those with magnetic susceptibility which are contraindicated for fMRI scanning. PMID:26132365

  12. Brain Activity During a Motor Learning Task: An fMRI and Skin Conductance Study

    PubMed Central

    MacIntosh, Bradley J.; Mraz, Richard; McIlroy, William E.; Graham, Simon J.

    2016-01-01

    Measuring electrodermal activity (EDA) during fMRI is an effective means of studying the influence of task-related arousal, inferred from autonomic nervous system activity, on brain activation patterns. The goals of this study were: (1) to measure reliable EDA from healthy individuals during fMRI involving an effortful unilateral motor task, (2) to explore how EDA recordings can be used to augment fMRI data analysis. In addition to conventional hemodynamic modeling, skin conductance time series data were used as model waveforms to generate activation images from fMRI data. Activations from the EDA model produced significantly different brain regions from those obtained with a standard hemodynamic model, primarily in the insula and cingulate cortices. Onsets of the EDA changes were synchronous with the hemodynamic model, but EDA data showed additional transient features, such as a decrease in amplitude with time, and helped to provide behavioral evidence suggesting task difficulty decreased with movement repetition. Univariate statistics also confirmed that several brain regions showed early versus late session effects. Partial least squares (PLS) multivariate analysis of EDA and fMRI data provided complimentary, additional insight on how the motor network varied over the course of a single fMRI session. Brain regions identified in this manner included the insula, cingulate gyrus, pre- and postcentral gyri, putamen and parietal cortices. These results suggest that recording EDA during motor fMRI experiments provides complementary information that can be used to improve the fMRI analysis, particularly when behavioral or task effects are difficult to model a priori. PMID:17318835

  13. MRI and low back pain

    MedlinePlus

    ... it is getting worse If you have low back pain but none of the warning signs just mentioned, having an MRI won't lead to better treatment, better pain relief, or a quicker return to activities. You and your doctor may want ...

  14. MRI Biosensors: A Short Primer

    PubMed Central

    Louie, Angelique

    2013-01-01

    Interest in Magnetic Resonance Imaging (MRI) contrast agents for molecular imaging of biological function experienced a surge of excitement approximately 20 years ago with the development of the first activatable contrast agents that could act as biosensors and turn “on” in response to a specific biological activity. This brief tutorial, based on a short course lecture from the 2011 ISMRM meeting, provides an overview of underlying principles governing the design of biosensing contrast agents. We describe mechanisms by which a magnetic resonance imaging (MRI) contrast agent can be made into a sensor for both T1 and T2 types contrast agents. Examples of biological activities that can interact with a contrast agent are discussed using specific examples from the recent literature to illustrate the primary mechanisms of action that have been utilized to achieve activation. MRI sensors for pH, ion binding, enzyme cleavage, and oxidation-reduction are presented. This article is not meant to be an exhaustive review, but an illustrative primer to explain how activation can be achieved for an MRI contrast agent. Chemical exchange saturation transfer (CEST) is not covered as these agents were covered in a separate lecture. PMID:23996662

  15. Volumetric MRI data correlate to disease severity in metachromatic leukodystrophy

    PubMed Central

    Tillema, Jan-Mendelt; Derks, Marloes GM; Pouwels, Petra J W; de Graaf, Pim; van Rappard, Diane F; Barkhof, Frederik; Steenweg, Marjan E; van der Knaap, Marjo S; Wolf, Nicole I

    2015-01-01

    Objective Metachromatic leukodystrophy (MLD) is an inherited lysosomal disorder due to a deficiency in arylsulfatase A with progressive demyelination and neurological decline. This retrospective MRI study investigated the extent of cortical involvement at time of diagnosis, and clinical correlates to both conventional and regional volumetric measures of brain involvement. Methods 3D-T1-weighted MRI scans were used to determine cortical thickness and surface-based cerebral cortical gray matter (GM) and cerebral white matter (WM) volume (GMV and WMV), WM lesions, thalamus, and cerebellum. MRI-MLD severity scores were obtained from FLAIR images. Associations between clinical and imaging data were examined using correlation coefficients. Results Twenty patients with MLD (mean age 13.7 years, range 2–35) and 20 controls (mean age 13.9 years, range 2–40) were included. Compared with control subjects, late-infantile, and juvenile patients (n = 14) had significantly diminished cerebral cortical GMV and thalamus volume (P < 0.05), but did not differ in WMV and cortical thickness. Adult patients (n = 6) showed significantly reduced GMV, WMV and cortical thickness (all P < 0.05). Regional analysis showed statistically significant cortical thinning in the cingulate gyrus and most pronounced thinning with age in the frontal lobe of MLD patients. Intelligence quotient (IQ) correlated with MRI-MLD scores (r = −0.87, P < 0.001). Interpretation Significant cerebral cortical GMV loss is already present in early stages of MLD. IQ correlates with WM severity scores and lesion volume, but not with volumetric measures. In adult presentations, there is more pronounced global atrophy with GMV and WMV loss and accelerated cortical thinning, most prominently in the cingulate gyrus and frontal lobes. PMID:26401514

  16. SU-E-J-03: Characterization of the Precision and Accuracy of a New, Preclinical, MRI-Guided Focused Ultrasound System for Image-Guided Interventions in Small-Bore, High-Field Magnets

    SciTech Connect

    Ellens, N; Farahani, K

    2015-06-15

    Purpose: MRI-guided focused ultrasound (MRgFUS) has many potential and realized applications including controlled heating and localized drug delivery. The development of many of these applications requires extensive preclinical work, much of it in small animal models. The goal of this study is to characterize the spatial targeting accuracy and reproducibility of a preclinical high field MRgFUS system for thermal ablation and drug delivery applications. Methods: The RK300 (FUS Instruments, Toronto, Canada) is a motorized, 2-axis FUS positioning system suitable for small bore (72 mm), high-field MRI systems. The accuracy of the system was assessed in three ways. First, the precision of the system was assessed by sonicating regular grids of 5 mm squares on polystyrene plates and comparing the resulting focal dimples to the intended pattern, thereby assessing the reproducibility and precision of the motion control alone. Second, the targeting accuracy was assessed by imaging a polystyrene plate with randomly drilled holes and replicating the hole pattern by sonicating the observed hole locations on intact polystyrene plates and comparing the results. Third, the practicallyrealizable accuracy and precision were assessed by comparing the locations of transcranial, FUS-induced blood-brain-barrier disruption (BBBD) (observed through Gadolinium enhancement) to the intended targets in a retrospective analysis of animals sonicated for other experiments. Results: The evenly-spaced grids indicated that the precision was 0.11 +/− 0.05 mm. When image-guidance was included by targeting random locations, the accuracy was 0.5 +/− 0.2 mm. The effective accuracy in the four rodent brains assessed was 0.8 +/− 0.6 mm. In all cases, the error appeared normally distributed (p<0.05) in both orthogonal axes, though the left/right error was systematically greater than the superior/inferior error. Conclusions: The targeting accuracy of this device is sub-millimeter, suitable for many

  17. Advances in Clinical PET/MRI Instrumentation.

    PubMed

    Herzog, Hans; Lerche, Christoph

    2016-04-01

    In 2010, the first whole-body PET/MRI scanners installed for clinical use were the sequential Philips PET/MRI with PMT-based, TOF-capable technology and the integrated simultaneous Siemens PET/MRI. Avalanche photodiodes as non-magneto-sensitive readout electronics allowed PET integrated within the MRI. The experiences with these scanners showed that improvements of software aspects, such as attenuation correction, were necessary and that efficient protocols combining optimally PET and MRI must be still developed. In 2014, General Electric issued an integrated PET/MRI with SiPM-based PET detectors, allowing TOF-PET. Looking at the MRI components of current PET/MR imaging systems, primary improvements come from sequences and new coils. PMID:26952724

  18. Peripheral late reactivation of a previously typical monofocal Baló's concentric sclerosis lesion.

    PubMed

    Pique, J; Bonneville, F; Brassat, D; Peaureaux, D; Benaiteau, M; Dumas, H; Fabre, N; Clanet, M; Biotti, D

    2015-07-01

    We report a 41-year-old woman with rapidly progressive left hemiparesis, revealing an inflammatory reactivation of a previously known parietal Baló's concentric sclerosis lesion. The first attack occurred five years before. After a slow recovery following high-dose steroid infusions the patient stabilized. Because of recurrent ataxia and left hemiparesis a new magnetic resonance imaging was performed showing an extension of the initial lesion with a peripheral gadolinium enhancement on T1-weighted images. Such a reactivation pattern of an isolated Baló's concentric sclerosis lesion, occurring some years later, is described for the first time. PMID:26014609

  19. Helping the Habitually Late Student.

    ERIC Educational Resources Information Center

    Bergman, Jerry

    1978-01-01

    The author gives three major reasons for a student being habitually late to class: resistance, disorganization, or unavoidable schedule conflicts. He makes specific suggestions to teachers for dealing with the disorganized and resistant latecomers. (SJL)

  20. Late Blooming or Language Problem?

    MedlinePlus

    ... and Swallowing / Disorders and Diseases Late Blooming or Language Problem? Parents are smart. They listen to their ... or not their child is developing speech and language at a normal rate. If parents think that ...

  1. Adhesions to Mesh after Ventral Hernia Mesh Repair Are Detected by MRI but Are Not a Cause of Long Term Chronic Abdominal Pain

    PubMed Central

    Langbach, Odd; Holmedal, Stein Harald; Grandal, Ole Jacob

    2016-01-01

    Aim. The aim of the present study was to perform MRI in patients after ventral hernia mesh repair, in order to evaluate MRI's ability to detect intra-abdominal adhesions. Materials and Methods. Single-center long term follow-up study of 155 patients operated for ventral hernia with laparoscopic (LVHR) or open mesh repair (OVHR), including analyzing medical records, clinical investigation with patient-reported pain (VAS-scale), and MRI. MRI was performed in 124 patients: 114 patients (74%) after follow-up, and 10 patients referred for late complaints after ventral mesh repair. To verify the MRI-diagnosis of adhesions, laparoscopy was performed after MRI in a cohort of 20 patients. Results. MRI detected adhesions between bowel and abdominal wall/mesh in 60% of the patients and mesh shrinkage in 20–50%. Adhesions were demonstrated to all types of meshes after both LVHR and OVHR with a sensitivity of 70%, specificity of 75%, positive predictive value of 78%, and negative predictive value of 67%. Independent predictors for formation of adhesions were mesh area as determined by MRI and Charlson index. The presence of adhesions was not associated with more pain. Conclusion. MRI can detect adhesions between bowel and abdominal wall in a fair reliable way. Adhesions are formed both after open and laparoscopic hernia mesh repair and are not associated with chronic pain. PMID:26819601

  2. Adhesions to Mesh after Ventral Hernia Mesh Repair Are Detected by MRI but Are Not a Cause of Long Term Chronic Abdominal Pain.

    PubMed

    Langbach, Odd; Holmedal, Stein Harald; Grandal, Ole Jacob; Røkke, Ola

    2016-01-01

    Aim. The aim of the present study was to perform MRI in patients after ventral hernia mesh repair, in order to evaluate MRI's ability to detect intra-abdominal adhesions. Materials and Methods. Single-center long term follow-up study of 155 patients operated for ventral hernia with laparoscopic (LVHR) or open mesh repair (OVHR), including analyzing medical records, clinical investigation with patient-reported pain (VAS-scale), and MRI. MRI was performed in 124 patients: 114 patients (74%) after follow-up, and 10 patients referred for late complaints after ventral mesh repair. To verify the MRI-diagnosis of adhesions, laparoscopy was performed after MRI in a cohort of 20 patients. Results. MRI detected adhesions between bowel and abdominal wall/mesh in 60% of the patients and mesh shrinkage in 20-50%. Adhesions were demonstrated to all types of meshes after both LVHR and OVHR with a sensitivity of 70%, specificity of 75%, positive predictive value of 78%, and negative predictive value of 67%. Independent predictors for formation of adhesions were mesh area as determined by MRI and Charlson index. The presence of adhesions was not associated with more pain. Conclusion. MRI can detect adhesions between bowel and abdominal wall in a fair reliable way. Adhesions are formed both after open and laparoscopic hernia mesh repair and are not associated with chronic pain. PMID:26819601

  3. Integration of DCE-MRI and DW-MRI Quantitative Parameters for Breast Lesion Classification

    PubMed Central

    Fusco, Roberta; Sansone, Mario; Filice, Salvatore; Granata, Vincenza; Catalano, Orlando; Amato, Daniela Maria; Di Bonito, Maurizio; D'Aiuto, Massimiliano; Capasso, Immacolata; Rinaldo, Massimo; Petrillo, Antonella

    2015-01-01

    Objective. The purpose of our study was to evaluate the diagnostic value of an imaging protocol combining dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DW-MRI) in patients with suspicious breast lesions. Materials and Methods. A total of 31 breast lesions (15 malignant and 16 benign proved by histological examination) in 26 female patients were included in this study. For both DCE-MRI and DW-MRI model free and model based parameters were computed pixel by pixel on manually segmented ROIs. Statistical procedures included conventional linear analysis and more advanced techniques for classification of lesions in benign and malignant. Results. Our findings indicated no strong correlation between DCE-MRI and DW-MRI parameters. Results of classification analysis show that combining of DCE parameters or DW-MRI parameter, in comparison of single feature, does not yield a dramatic improvement of sensitivity and specificity of the two techniques alone. The best performance was obtained considering a full combination of all features. Moreover, the classification results combining all features are dominated by DCE-MRI features alone. Conclusion. The combination of DWI and DCE-MRI does not show a potential to dramatically increase the sensitivity and specificity of breast MRI. DCE-MRI alone gave the same performance as in combination with DW-MRI. PMID:26339597

  4. Late effects from hadron therapy

    SciTech Connect

    Blakely, Eleanor A.; Chang, Polly Y.

    2004-06-01

    Successful cancer patient survival and local tumor control from hadron radiotherapy warrant a discussion of potential secondary late effects from the radiation. The study of late-appearing clinical effects from particle beams of protons, carbon, or heavier ions is a relatively new field with few data. However, new clinical information is available from pioneer hadron radiotherapy programs in the USA, Japan, Germany and Switzerland. This paper will review available data on late tissue effects from particle radiation exposures, and discuss its importance to the future of hadron therapy. Potential late radiation effects are associated with irradiated normal tissue volumes at risk that in many cases can be reduced with hadron therapy. However, normal tissues present within hadron treatment volumes can demonstrate enhanced responses compared to conventional modes of therapy. Late endpoints of concern include induction of secondary cancers, cataract, fibrosis, neurodegeneration, vascular damage, and immunological, endocrine and hereditary effects. Low-dose tissue effects at tumor margins need further study, and there is need for more acute molecular studies underlying late effects of hadron therapy.

  5. MRI of Focal Liver Lesions.

    PubMed

    Albiin, Nils

    2012-05-01

    Magnetic resonance imaging, MRI has more advantages than ultrasound, computed tomography, CT, positron emission tomography, PET, or any other imaging modality in diagnosing focal hepatic masses. With a combination of basic T1 and T2 weighted sequences, diffusion weighted imaging, DWI, and hepatobiliary gadolinium contrast agents, that is gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB), most liver lesions can be adequately diagnosed. Benign lesions, as cyst, hemangioma, focal nodular hyperplasia, FNH or adenoma, can be distinguished from malignant lesions. In a non-cirrhotic liver, the most common malignant lesions are metastases which may be hypovascular or hypervascular. In the cirrhotic liver hepatocellular carcinoma, HCC, is of considerable importance. Besides, intrahepatic cholangiocarcinoma and other less common malignancies has to be assessed. In this review, the techniques and typical MRI features are presented as well as the new algorithm issued by American Association for the Study of the Liver Diseases (AASLD). PMID:23049491

  6. Polycatechol Nanoparticle MRI Contrast Agents.

    PubMed

    Li, Yiwen; Huang, Yuran; Wang, Zhao; Carniato, Fabio; Xie, Yijun; Patterson, Joseph P; Thompson, Matthew P; Andolina, Christopher M; Ditri, Treffly B; Millstone, Jill E; Figueroa, Joshua S; Rinehart, Jeffrey D; Scadeng, Miriam; Botta, Mauro; Gianneschi, Nathan C

    2016-02-01

    Amphiphilic triblock copolymers containing Fe(III) -catecholate complexes formulated as spherical- or cylindrical-shaped micellar nanoparticles (SMN and CMN, respectively) are described as new T1-weighted agents with high relaxivity, low cytotoxicity, and long-term stability in biological fluids. Relaxivities of both SMN and CMN exceed those of established gadolinium chelates across a wide range of magnetic field strengths. Interestingly, shape-dependent behavior is observed in terms of the particles' interactions with HeLa cells, with CMN exhibiting enhanced uptake and contrast via magnetic resonance imaging (MRI) compared with SMN. These results suggest that control over soft nanoparticle shape will provide an avenue for optimization of particle-based contrast agents as biodiagnostics. The polycatechol nanoparticles are proposed as suitable for preclinical investigations into their viability as gadolinium-free, safe, and effective imaging agents for MRI contrast enhancement. PMID:26681255

  7. In Vivo Imaging of Stepwise Vessel Occlusion in Cerebral Photothrombosis of Mice by 19F MRI

    PubMed Central

    Kleinschnitz, Christoph; Kampf, Thomas; Jakob, Peter M.; Stoll, Guido

    2011-01-01

    Background 19F magnetic resonance imaging (MRI) was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared 19F MRI with iron-enhanced MRI in mice with photothrombosis (PT) at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation. Methods/Principal Findings Perfluorocarbons (PFC) or superparamagnetic iron oxide particles (SPIO) were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong 19F signal throughout the entire lesion, two hours delayed application resulted in a rim-like 19F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the 19F markers (infarct core/rim) could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage. Conclusion Our study shows that vessel occlusion can be followed in vivo by 19F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement. PMID:22194810

  8. Future perspectives for intraoperative MRI.

    PubMed

    Jolesz, Ferenc A

    2005-01-01

    MRI-guided neurosurgery not only represents a technical challenge but a transformation from conventional hand-eye coordination to interactive navigational operations. In the future, multimodality-based images will be merged into a single model, in which anatomy and pathologic changes are at once distinguished and integrated into the same intuitive framework. The long-term goals of improving surgical procedures and attendant outcomes, reducing costs, and achieving broad use can be achieved with a three-pronged approach: 1. Improving the presentation of preoperative and real-time intraoperative image information 2. Integrating imaging and treatment-related technology into therapy delivery systems 3. Testing the clinical utility of image guidance in surgery The recent focus in technology development is on improving our ability to understand and apply medical images and imaging systems. Areas of active research include image processing, model-based image analysis, model deformation, real-time registration, real-time 3D (so-called "four-dimensional") imaging, and the integration and presentation of image and sensing information in the operating room. Key elements of the technical matrix also include visualization and display platforms and related software for information and display, model-based image understanding, the use of computing clusters to speed computation (ie, algorithms with partitioned computation to optimize performance), and advanced devices and systems for 3D device tracking (navigation). Current clinical applications are successfully incorporating real-time and/or continuously up-dated image-based information for direct intra-operative visualization. In addition to using traditional imaging systems during surgery, we foresee optimized use of molecular marker technology, direct measures of tissue characterization (ie, optical measurements and/or imaging), and integration of the next generation of surgical and therapy devices (including image

  9. How to scan polymer gels with MRI?

    NASA Astrophysics Data System (ADS)

    De Deene, Y.

    2013-06-01

    The absorbed radiation dose fixated in a polymer gel dosimeter can be read out by several methods such as magnetic resonance imaging (MRI), optical CT, X-ray CT and ultrasound with MRI being the first method that was explored. Although MRI was considered as an elegant scanning technique, readily available in most hospitals, it was later found that using a non-optimized imaging protocol may result in unacceptable deviations in the obtained dose distribution. Although most medical physicists have an understanding of the basic principles of magnetic resonance imaging (MRI), the optimization of quantitative imaging sequences and protocols is often perceived as the work of MRI experts. In this paper, we aim at providing the reader with some easy guidelines in how to obtain reliable quantitative MRI maps.

  10. Left Ventricular Aneurysm and Ventricular Tachycardia as Initial Presentation of Cardiac Sarcoidosis

    PubMed Central

    Jmeian, Ashraf; Thawabi, Mohammad; Goldfarb, Irvin; Shamoon, Fayez

    2015-01-01

    Context: Cardiac sarcoidosis (CS) is a rare, potentially fatal disease. It has a wide range of clinical presentations that range from asymptomatic electrocardiogram changes to sudden cardiac death. Ventricular aneurysms and ventricular tachycardia are seen late in the disease, and are rarely the presenting manifestation of the disease. Diagnosis of CS is challenging and often missed or delayed. Case Report: We report a 35-year-old patient who presented with sustained ventricular tachycardia and ST-elevation on electrocardiogram. Cardiac catheterization showed normal coronaries and left ventricular aneurysm. Subsequent 2D-echocardiography showed an infiltrative disease pattern. Cardiac MRI was done and showed late gadolinium enhancement in the septum, apex and lateral wall. The patient was diagnosed with cardiac sarcoidosis and treated with immune suppression and antiarrhythmic agent. In addition underwent AICD implantation. Conclusion: Our case highlights the importance of suspecting cardiac sarcoidosis in young patients presenting with electrocardiogram changes, and present an atypical presentation of this disease. PMID:25839003

  11. MRI Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Resonance Imaging) (Arabic) العربية Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) MRI (Magnetic Resonance Imaging) 核磁共振成像(MRI) - 简体中文 (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (繁體中文) MRI (Magnetic Resonance Imaging) 核磁共振成像( ...

  12. Integrated speech enhancement for functional MRI environment.

    PubMed

    Pathak, Nishank; Milani, Ali A; Panahi, Issa; Briggs, Richard

    2009-01-01

    This paper presents an integrated speech enhancement (SE) method for the noisy MRI environment. We show that the performance of SE system improves considerably when the speech signal dominated by MRI acoustic noise at very low SNR is enhanced in two successive stages using two-channel SE methods followed by a single-channel post processing SE algorithm. Actual MRI noisy speech data are used in our experiments showing the improved performance of the proposed SE method. PMID:19964964

  13. Competitive Advantage of PET/MRI

    PubMed Central

    Jadvar, Hossein; Colletti, Patrick M.

    2013-01-01

    Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. PMID:23791129

  14. Competitive advantage of PET/MRI.

    PubMed

    Jadvar, Hossein; Colletti, Patrick M

    2014-01-01

    Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. PMID:23791129

  15. PET/MRI: challenges, solutions and perspectives.

    PubMed

    Herzog, Hans

    2012-12-01

    Already from the start of PET/CT integrating positron emission tomography (PET) and computed tomography (CT) in one instrument, there have been considerations how to combine PET and magnetic resonance imaging (MRI) so that their complementary abilities can be utilized in a single investigation. Since classical PET electronics fail in an even weak magnetic field and PET signal processing might disturb high-frequency signals of MRI, it soon became clear that new solutions had to be found to avoid mutual interferences. During the last fifteen years a number of different approaches towards PET/MRI for small animal imaging have been developed by research groups which together with their specific features are summarized in this review. Recently, PET/MRI for human imaging became available as well - this time by industrial initiatives. First some prototypes of BrainPET/MRI were developed followed by commercial products for simultaneous and non-simultaneous whole-body PET/MRI. Although only PET/MRI integrated in one scanner offers the full diversity of complementary multiparametric imaging, there are also promising applications of non-simultaneous sequential PET/MRI. While describing the present instrumentation for human PET/MRI, this review discusses the challenges and promises related to this new imaging technology. PMID:22925652

  16. Sparse representation of complex MRI images.

    PubMed

    Nandakumar, Hari Prasad; Ji, Jim

    2008-01-01

    Sparse representation of images acquired from Magnet Resonance Imaging (MRI) has several potential applications. MRI is unique in that the raw images are complex. Complex wavelet transforms (CWT) can be used to produce flexible signal representations when compared to Discrete Wavelet Transform (DWT). In this work, five different schemes using CWT or DWT are tested for sparse representation of MRI images which are in the form of complex values, separate real/imaginary, or separate magnitude/phase. The experimental results on real in-vivo MRI images show that appropriate CWT, e.g., dual-tree CWT (DTCWT), can achieve sparsity better than DWT with similar Mean Square Error. PMID:19162677

  17. Functional MRI and Outcome in Traumatic Coma

    PubMed Central

    Giacino, Joseph T.; Wu, Ona

    2013-01-01

    Advances in task-based functional MRI (fMRI), resting-state fMRI (rs-fMRI), and arterial-spin labeled (ASL) perfusion MRI have occurred at a rapid pace in recent years. These techniques for measuring brain function have great potential to improve the accuracy of prognostication for civilian and military patients with traumatic coma. In addition, fMRI, rs-fMRI, and ASL have provided novel insights into the pathophysiology of traumatic disorders of consciousness, as well as mechanisms of recovery from coma. However, functional neuroimaging techniques have yet to achieve widespread clinical use as prognostic tests for patients with traumatic coma. Rather, a broad spectrum of methodological hurdles currently limits the feasibility of clinical implementation. In this review, we discuss the basic principles of fMRI, rs-fMRI and ASL and their potential applications as prognostic tools for patients with traumatic coma. We also discuss future strategies for overcoming the current barriers to clinical implementation. PMID:23881623

  18. Late-Notice HIE Investigation

    NASA Technical Reports Server (NTRS)

    Hejduk, M. D.

    2016-01-01

    Provide a response to MOWG action item 1410-01: Analyze close approaches which have required mission team action on short notice. Determine why the approaches were identified later in the process than most other events. Method: Performed an analysis to determine whether there is any correlation between late notice event identification and space weather, sparse tracking, or high drag objects, which would allow preventive action to be taken Examined specific late notice events identified by missions as problematic to try to identify root cause and attempt to relate them to the correlation analysis.

  19. Late Silurian plutons in Yucatan

    NASA Astrophysics Data System (ADS)

    Steiner, M. B.; Walker, J. Douglas

    1996-08-01

    U-Pb measurements of zircons from two composite plutons in the Maya Mountains of the Yucatan Block (Belize) give Late Silurian ages. Zircons from one of the five compositional phases of the Mountain Pine Ridge pluton yield an age of 418±3.6 Ma. A second compositional phase gives a minimum age of 404 Ma, and zircons from a third phase, although plagued with high common Pb, yield ages consistent with the other two. Zircons from one compositional phase of the Hummingbird-Mullins River pluton indicate an age of about 410-420 Ma. These data demonstrate that two of the three Maya Mountains plutons residing among the strata of the Late Pennsylvanian through Permian Santa Rosa Group are older than that sedimentation. Although the third pluton was not dated, both the similarity of sedimentary facies patterns adjacent to it to those adjacent to one of the plutons dated as Late Silurian and a published single Rb-Sr age of 428 ± 41 Ma suggest this third pluton also was emergent during Santa Rosa deposition. Thus the new U/Pb dates and other data suggest that all three Maya Mountains plutons pre-date Late Carboniferous sedimentation and that none intrude the Santa Rosa Group. Although very uniform ages of about 230 Ma amongst all plutons, derived from abundant earlier dating by the K-Ar system, led to the conclusion that intrusion mostly had occurred in the Late Triassic, the U-Pb ages (obtained from the same sites as the K-Ar dates) demonstrate that the K-Ar ages do not derive from a Late Triassic intrusive episode. The K-Ar dates probably are a signature of the rifting associated with Pangean breakup and formation of the Gulf of Mexico. In a reconstructed Pangea, the position of the Maya Mountains Late Silurian plutons suggests that the Late Silurian Acadian-Caledonian orogen of eastern North America extended through the region of the future Gulf of Mexico. Finally, the U-Pb ages of the Maya Mountains plutons are the same as those of a group of shocked zircons found in the

  20. The diagnostic value of MRI fistulogram and MRI distal colostogram in patients with anorectal malformations.

    PubMed

    Kavalcova, Lucie; Skaba, Richard; Kyncl, Martin; Rouskova, Blanka; Prochazka, Ales

    2013-08-01

    Contrast fistulogram (FG) and distal pressure colostogram (DPCG) are standard diagnostic methods for the assessment of anorectal malformations. Pelvic magnetic resonance imaging (MRI) earned a place among essential diagnostic methods in preoperative investigations after the Currarino syndrome and a high incidence of associated spinal dysraphism were described. The aim of our study was to evaluate the possibility of substituting FG and DPCG by a modified pelvic MRI, e.g. MRI fistulogram (MRI-FG) and MRI colostogram (MRI-DPCG). The prospective study involved 29 patients with anorectal malformations who underwent a modified pelvic MRI. The length and course of fistulas and rectum, and the presence of sacral anomalies were studied on MRI images and compared with images obtained by radiologic examinations. Modified MRI brought identical results as contrast studies in 25 patients when related to the fistula and rectum length and course. MRI was more accurate for the detection of sacral anomalies. MRI-FG was the only imaging method used in the four most recent patients. The results support the assumption that conventional contrast examinations for the assessment of anorectal malformations can be replaced by MRI, thus reducing the radiation dose. PMID:23932626

  1. [Late-onset depression : Pathophysiology, diagnostics and treatment].

    PubMed

    Notzon, S; Alferink, J; Arolt, V

    2016-09-01

    Late-onset depression (LOD) is defined as depression manifesting for the first time in later life. Up to now, there has been no exact definition of the lower age limit for LOD. Psychopathological symptoms of LOD do not fundamentally differ from depression in other phases of life; however, cognitive deficits are typically more pronounced. The LOD is associated with an increased risk of developing dementia. Imaging studies show reduction in gray matter volume and white matter lesions caused by vascular diseases. The occurrence of depression with vascular lesions of the brain is also referred to as "vascular depression". The diagnostic procedure includes a detailed medical history and the observation of psychopathological changes, physical examination, laboratory tests, electroencephalograph (EEG), electrocardiograph (ECG) and magnetic resonance imaging (MRI) of the head and neuropsychological tests to measure cognitive deficits. Psychotherapy is an effective treatment option. Selective serotonin reuptake inhibitors are the first-line pharmacological therapy. PMID:27531211

  2. Late-onset congenital lateral dermal sinus tract.

    PubMed

    Nishimon, Mari; Shimizu, Yusuke; Ueno, Mari; Iwanami, Akio

    2014-01-01

    Cases of laterally located, congenital dermal sinus tracts are extremely rare, with only six having been reported to date. We describe a case of a 14-year-old girl who developed symptoms of this type of sinus tract at an age that was considerably older than is usually reported. At the age of 12 years, the patient exhibited a purulent discharge from a pit on the right buttock. MRI indicated the presence of two tracts running from the right buttock skin to a cystic lesion that had formed on the right ala of the sacral spine. The lesion was surgically resected and successfully reconstructed using a partial iliocostalis lumborum muscle flap, without any functional morbidity. From our experience, such flaps appear to be appropriate treatment choices for lateral congenital dermal sinus tracts that develop late and result in large defects. PMID:25535223

  3. Late-onset Leigh syndrome with myoclonic epilepsy with ragged-red fibers.

    PubMed

    Monden, Yukifumi; Mori, Masato; Kuwajima, Mari; Goto, Tamako; Yamagata, Takanori; Momoi, Mariko Y

    2013-06-01

    We report the case of a boy with myoclonic epilepsy with ragged-red fibers (MERRF) who had astatic seizures since 2 years of age and later developed ataxia, absence seizures, and myoclonus. Almost homoplasmic A8344G mutation of mitochondrial DNA (m.8344A>G mutation) was detected in lymphocytes. He developed late-onset Leigh syndrome (LS) when he contracted pneumonia at 6 years. He developed bulbar palsy and deep coma. MRI demonstrated lesions in the brainstem, basal ganglia, and cerebral cortex. Three similar cases have been reported; two carried the almost-homoplasmic m.8344A>G mutation in muscle tissue. These suggested that almost homoplastic m.8344A>G mutation developed clinical phenotype of MERRF in the early stage and late-onset Leigh syndrome in the late course of the disease. PMID:22981260

  4. Planetary science: Ubiquitous late veneer

    NASA Astrophysics Data System (ADS)

    Brenan, James

    2012-09-01

    Iron-loving elements are thought to have been added to Mars, Earth and the Moon after core formation. An analysis of meteorites formed in the first two to three million years of Solar System history suggests that a similar late veneer was added elsewhere too.

  5. Late onset globoid cell leukodystrophy.

    PubMed Central

    Grewal, R P; Petronas, N; Barton, N W

    1991-01-01

    A 29 year old male with onset of globoid cell leukodystrophy at age 14 is described. This is the first case of enzymatically confirmed globoid cell leukodystrophy with onset of symptoms after the age of ten. This patient is unique because of the late onset and slow progression and extends the clinical spectrum of globoid cell leukodystrophy. Images PMID:1800646

  6. Early and Late Retirement Exits

    ERIC Educational Resources Information Center

    Brougham, Ruby R.; Walsh, David A.

    2009-01-01

    The current study proposes that personal need fulfillment (relatedness, generativity, identity, growth, and finances) predicts early and late retirement intentions. The personal needs of 160 full-time older employees were measured by personal goals, job satisfactions, job characteristics, and intrinsic motivation. Results suggest that the personal…

  7. Sheehan syndrome: a splinter of the mind.

    PubMed

    Vaphiades, Michael S; Simmons, Debra; Archer, Robert L; Stringer, Warren

    2003-01-01

    A 40-year-old woman presented with headache and diplopia after hypotension from postpartum hemorrhage. A noncontrasted cranial magnetic resonance imaging (MRI) showed an enlarged pituitary with a rim of slight increased signal. A repeat gadolinium-enhanced cranial MRI showed peripheral enhancement of the pituitary gland surrounding an isointense central area consistent with infarction of the pituitary and the clinical diagnosis of Sheehan syndrome. The patient was treated with intravenous hydrocortisone. Immediately after treatment, her symptoms remitted and the examination normalized. One month later, a gadolinium-enhanced cranial MRI was normal. The characteristic appearance of the post-gadolinium enhanced cranial MRI helped confirm the diagnosis of Sheehan syndrome and facilitate early treatment with corticosteroids. PMID:12686307

  8. Optimized Breast MRI Functional Tumor Volume as a Biomarker of Recurrence-Free Survival Following Neoadjuvant Chemotherapy

    PubMed Central

    Jafri, Nazia F.; Newitt, David C.; Kornak, John; Esserman, Laura J.; Joe, Bonnie N.; Hylton, Nola M.

    2015-01-01

    Purpose To evaluate optimal contrast kinetics thresholds for measuring functional tumor volume (FTV) by breast magnetic resonance imaging (MRI) for assessment of recurrence-free survival (RFS). Materials and Methods In this Institutional Review Board (IRB)-approved retrospective study of 64 patients (ages 29–72, median age of 48.6) undergoing neoadjuvant chemotherapy (NACT) for breast cancer, all patients underwent pre-MRI1 and postchemotherapy MRI4 of the breast. Tumor was defined as voxels meeting thresholds for early percent enhancement (PEthresh) and early-to-late signal enhancement ratio (SERthresh); and FTV (PEthresh, SERthresh) by summing all voxels meeting threshold criteria and minimum connectivity requirements. Ranges of PEthresh from 50% to 220% and SERthresh from 0.0 to 2.0 were evaluated. A Cox proportional hazard model determined associations between change in FTV over treatment and RFS at different PE and SER thresholds. Results The plot of hazard ratios for change in FTV from MRI1 to MRI4 showed a broad peak with the maximum hazard ratio and highest significance occurring at PE threshold of 70% and SER threshold of 1.0 (hazard ratio = 8.71, 95% confidence interval 2.86–25.5, P < 0.00015), indicating optimal model fit. Conclusion Enhancement thresholds affect the ability of MRI tumor volume to predict RFS. The value is robust over a wide range of thresholds, supporting the use of FTV as a biomarker. PMID:24347097

  9. LATE-AGE ONSET SCLERODERMA

    PubMed Central

    Manno, Rebecca L.; Wigley, Fredrick M.; Gelber, Allan C.; Hummers, Laura K.

    2011-01-01

    OBJECTIVE Although patients who develop scleroderma (SSc) later in life (≥ 65 years) may express the entire clinical spectrum of disease, we hypothesize that patients with late-age onset incur a different risk for specific organ manifestations of disease compared to those with younger-age onset SSc. METHODS In total, 2300 SSc patients were evaluated between 1990–2009 and reviewed from a university-based Scleroderma Center cohort. Demographic profile, SSc subtype, autoantibody status, Medsger severity scores, pulmonary function tests, echocardiography, and right heart catheterization parameters were compared between late-age versus younger-age onset patients. RESULTS Overall, 2084 (91%) patients developed SSc prior to age 65; whereas 216 (9%) were ≥65 years. Late-age onset patients had a significantly higher proportion of anti-centromere antibodies (42% vs 27%; p=0.001) compared to younger-age onset. Risk of pulmonary hypertension (OR 1.77; 95%CI 1.00, 3.12), muscle weakness (OR 1.85; 95%CI 1.30, 2.64), renal impairment (OR 2.83; 95%CI 1.98, 4.04) and cardiac disease (OR 2.69; 95%CI 1.92, 3.78) was greater among those with late-age onset SSc; although risk of digital ischemia (OR 0.64; 95%CI 0.47, 0.86) was reduced. The cumulative incidence of pulmonary hypertension at 5 years was greater among those with late-age (9%) compared to younger-age (2.5%) onset SSc (log-rank, p<0.001). CONCLUSION These findings suggest that older SSc patients are at greater risk for pulmonary hypertension, renal impairment, cardiac disease, and muscle weakness. Awareness of the distinct risk for specific organ manifestations in SSc, in particular pulmonary hypertension, should guide the care of older SSc patients whose disease begins after age 65 years. PMID:21685299

  10. Pantopaque simulating thrombosed intracranial aneurysms on MRI

    SciTech Connect

    Lidov, M.W.; Silvers, A.R.; Mosesson, R.E.; Stollman, A.L.; Som, P.M.

    1996-03-01

    A patient is presented in whom iophendylate (Pantopaque) within the basal cisterns closely resembled the appearance on MRI of thrombosed aneurysms of the middle cerebral arteries. The sometimes subtle differences between the appearances on MRI of Pantopaque and aneurysmal clot are discussed to permit accurate diagnosis without resorting to more invasive diagnostic tests, such as cerebral angiography. 5 refs., 4 figs.