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Sample records for late gadolinium-enhanced mri

  1. [Studies of three-dimensional cardiac late gadolinium enhancement MRI at 3.0 Tesla].

    PubMed

    Ishimoto, Takeshi; Ishihara, Masaru; Ikeda, Takayuki; Kawakami, Momoe

    2008-12-20

    Cardiac late Gadolinium enhancement MR imaging has been shown to allow assessment of myocardial viability in patients with ischemic heart disease. The current standard approach is a 3D inversion recovery sequence at 1.5 Tesla. The aims of this study were to evaluate the technique feasibility and clinical utility of MR viability imaging at 3.0 Tesla in patients with myocardial infarction and cardiomyopathy. In phantom and volunteer studies, the inversion time required to suppress the signal of interests and tissues was prolonged at 3.0 Tesla. In the clinical study, the average inversion time to suppress the signal of myocardium at 3.0 Tesla with respect to MR viability imaging at 1.5 Tesla was at 15 min after the administration of contrast agent (304.0+/-29.2 at 3.0 Tesla vs. 283.9+/-20.9 at 1.5 Tesla). The contrast between infarction and viable myocardium was equal at both field strengths (4.06+/-1.30 at 3.0 Tesla vs. 4.42+/-1.85 at 1.5 Tesla). Even at this early stage, MR viability imaging at 3.0 Tesla provides high quality images in patients with myocardial infarction. The inversion time is significantly prolonged at 3.0 Tesla. The contrast between infarction and viable myocardium at 3.0 Tesla are equal to 1.5 Tesla. Further investigation is needed for this technical improvement, for clinical evaluation, and for limitations.

  2. 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

  3. 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.

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

    PubMed

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

    2012-02-23

    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.

  5. Dressler's syndrome demonstrated by late gadolinium enhancement cardiovascular magnetic resonance

    PubMed Central

    Steadman, Christopher D; Khoo, Jeffrey; Kovac, Jan; McCann, Gerry P

    2009-01-01

    A 49-year old patient presented late with an anterolateral ST-elevation myocardial infarction and was treated with rescue angioplasty to an occluded left anterior descending artery. Her recovery was complicated by low-grade pyrexia and raised inflammatory markers. Cardiovascular magnetic resonance 5 weeks after the acute presentation showed transmural infarction and global late gadolinium enhancement of the pericardium in keeping with Dressler's syndrome. PMID:19627595

  6. MRI gadolinium enhancement precedes neuroradiological findings in acute necrotizing encephalopathy.

    PubMed

    Yoshida, Takeshi; Tamura, Takuya; Nagai, Yuhki; Ueda, Hiroyuki; Awaya, Tomonari; Shibata, Minoru; Kato, Takeo; Heike, Toshio

    2013-11-01

    We report a 2-year-old Japanese boy with acute necrotizing encephalopathy (ANE) triggered by human herpes virus-6, who presented insightful magnetic resonance imaging (MRI) findings. He was admitted due to impaired consciousness and a convulsion, 2 days after the onset of an upper respiratory infection. At admission, cranial MRI showed marked gadolinium enhancement at the bilateral thalami, brainstem and periventricular white matter without abnormal findings in noncontrast MRI sequences. On the following day, noncontrast computed tomography demonstrated homogeneous low-density lesions in the bilateral thalami and severe diffuse brain edema. The patient progressively deteriorated and died on the 18th day of admission. The pathogenesis of ANE remains mostly unknown, but it has been suggested that hypercytokinemia may play a major role. Overproduced cytokines cause vascular endothelial damage and alter the permeability of the vessel wall in the multiple organs, including the brain. The MRI findings in our case demonstrate that blood-brain barrier permeability was altered prior to the appearance of typical neuroradiological findings. This suggests that alteration of blood-brain barrier permeability is the first step in the development of the brain lesions in ANE, and supports the proposed mechanism whereby hypercytokinemia causes necrotic brain lesions. This is the first report demonstrating MRI gadolinium enhancement antecedent to typical neuroradiological findings in ANE.

  7. Sector-Based Assessment of Infarct Size on Late-Gadolinium-Enhancement MRI in a Mouse Model of Acute Myocardial Infarction.

    PubMed

    Park, Cheongsoo; Park, Eun-Hye; Chang, Kiyuk; Hong, Kwan Soo

    2016-12-02

    Scoring of myocardial infarction (MI) disease extent in cardiac magnetic resonance (CMR) images has been generally presented in terms of area-based infarct size. However, gradual thinning of the infarcted wall and compensatory hypertrophy of the noninfarcted remote wall during left ventricular (LV) remodeling after MI complicate the accuracy of infarct size measurement. In this study, we measured and compared infarct sizes in mice on late gadolinium enhancement (LGE) images using area-, length-, and radial sector-based methods.MI was induced by permanent ligation of the left coronary artery (n = 6). LGE images were acquired 30 minutes after intravenous injection of Gd-DTPA-BMA. Percentages of infarct size (%Area, %Length, and %Sector) on the LGE images were calculated and compared with histological findings.Infarct sizes obtained by an area-based approach were smaller than those obtained by other measurements. The area-based approach underestimated infarct size compared with the length-based approach. Most infarct sizes measured by each method demonstrated a similar trend, with maximum values determined by sector-based measurements using a mean + SD threshold. Spearman's rank correlation coefficients indicated that the 3 measurements were strongly correlated (P < 0.05) to each other. Significant differences and trends were observed between sector-based infarct sizes with different thresholds when 16 or more sectors were used.In conclusion, our study demonstrated that methods used for the histological calculation of infarct size could be applied to CMR analysis. Moreover, our results showed a similar trend to histological assessment. Sector-based CMR approaches can be useful for infarct size measurement.

  8. Late Gadolinium Enhancement in Patients with Nonischemic Dilated Cardiomyopathy.

    PubMed

    Memon, Sarfaraz; Ganga, Harsha V; Kluger, Jeffrey

    2016-07-01

    One-third of all patients with heart failure have nonischemic dilated cardiomyopathy (NIDM). Five-year mortality from NIDM is as high as 20% with sudden cardiac death (SCD) as the cause in 30% of the deaths. Currently, the left ventricular ejection fraction (LVEF) is used as the main criteria to risk stratify patients requiring an implantable cardioverter defibrillator (ICD) to prevent SCD. However, LVEF does not necessarily reflect myocardial propensity for electrical instability leading to ventricular tachycardia (VT) or ventricular fibrillation (VF). Due to the differential risk in various subgroups of patients for arrhythmic death, it is important to identify appropriate patients for ICD implantation so that we can optimize healthcare resources and avoid the complications of ICDs in individuals who are unlikely to benefit. We performed a systematic search and review of clinical trials of NIDM and the use of ICDs and cardiac magnetic resonance imaging with late gadolinium enhancement (LGE) for risk stratification. LGE identifies patients with NIDM who are at high risk for SCD and enables optimized patient selection for ICD placement, while the absence of LGE may reduce the need for ICD implantation in patients with NIDM who are at low risk for future VF/VT or SCD.

  9. Comparison of Ventricular Inducibility with Late Gadolinium Enhancement and Myocardial Inflammation in Endomyocardial Biopsy in Patients with Dilated Cardiomyopathy

    PubMed Central

    Mueller, Karin A. L.; Heck, Christian; Heinzmann, David; Schwille, Johannes; Klingel, Karin; Kandolf, Reinhard; Kramer, Ulrich; Gramlich, Michael; Geisler, Tobias; Gawaz, Meinrad P.

    2016-01-01

    Background Risk stratification of patients with non-ischemic dilated cardiomyopathy remains a matter of debate in the era of device implantation. Objective We investigated associations between histopathological findings, contrast-enhanced cardiac MRI and the inducibility of ventricular tachycardia (VT) or fibrillation (VF) in programmed ventricular stimulation. Methods 56 patients with impaired left ventricular ejection fraction (LVEF≤50%, mean 36.6±10.5%) due to non-ischemic dilated cardiomyopathy underwent cardiac MRI, programmed ventricular stimulation, and endomyocardial biopsy and were retrospectively investigated. Inducibility was defined as sustained mono- or polymorphic VT or unstable VT/VF requiring cardioversion/defibrillation. Primary study endpoint was defined as the occurrence of hemodynamically relevant VT/VF and/or adequate ICD-therapy during follow-up. Results Endomyocardial biopsy detected cardiac fibrosis in 18 (32.1%) patients. Cardiac MRI revealed 35 (62.5%) patients with positive late gadolinium enhancement. VT/VF was induced in ten (17.9%) patients during programmed ventricular stimulation. Monomorphic VT was inducible in 70%, while 20% of patients showed polymorphic VT. One patient (10%) presented with VF. Inducibility correlated significantly with the presence of positive late gadolinium enhancement in cardiac MRI (p<0.01). We could not find a significant association between inducibility and the degree of cardiac inflammation and fibrosis in non-site directed routine right ventricular endomyocardial biopsy. During a mean follow-up of 2.6 years, nine (16.1%) patients reached the primary endpoint. Monomorphic VTs were found in 66.7% patients and were terminated by antitachycardia pacing therapy. One patient with polymorphic VT and two patients with VF received adequate therapy by an ICD-shock. However, inducibility did not correlate with the occurrence of endpoints. Conclusion Inducibilty during programmed ventricular stimulation is

  10. Myocardial late gadolinium enhancement in specific cardiomyopathies by cardiovascular magnetic resonance: a preliminary experience.

    PubMed

    Silva, Caterina; Moon, James C; Elkington, Andrew G; John, Anna S; Mohiaddin, Raad H; Pennell, Dudley J

    2007-12-01

    Late gadolinium enhancement cardiovascular magnetic resonance (CMR) can visualize myocardial interstitial abnormalities. The aim of this study was to assess whether regions of abnormal myocardium can also be visualized by late enhancement gadolinium CMR in the specific cardiomyopathies. A retrospective review of all referrals for gadolinium CMR with specific cardiomyopathy over 20 months. Nine patients with different specific cardiomyopathies were identified. Late enhancement was demonstrated in all patients, with a mean signal intensity of 390 +/- 220% compared with normal regions. The distribution pattern of late enhancement was unlike the subendocardial late enhancement related to coronary territories found in myocardial infarction. The affected areas included papillary muscles (sarcoid), the mid-myocardium (Anderson-Fabry disease, glycogen storage disease, myocarditis, Becker muscular dystrophy) and the global sub-endocardium (systemic sclerosis, Loeffler's endocarditis, amyloid, Churg-Strauss). Focal myocardial late gadolinium enhancement is found in the specific cardiomyopathies, and the pattern is distinct from that seen in infarction. Further systematic studies are warranted to assess whether the pattern and extent of late enhancement may aid diagnosis and prognostic assessment.

  11. Characterizing Prostiva RF treatments of the prostate for BPH with gadolinium-enhanced MRI.

    PubMed

    Huidobro, Christian; Larson, Benjamin; Mynderse, Samuel; Myers, James J; Busel, David; Acevedo, Cristian; Larson, Thayne R; Mynderse, Lance A

    2009-01-18

    Transurethral needle ablation (TUNA) is an accepted and effective therapy for the treatment of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Prostiva (Medtronic, Shoreview, MN) is the newest-generation device, which includes a new needle design and radio frequency (RF) generator. This device creates temperatures of 120 degrees C and necrotic lesions in less than 2.5 min. Using previously described techniques, we analyzed dynamic, gadolinium-enhanced MRIs to characterize the ablative properties of the new Prostiva RF device. Ten men with LUTS due to BPH were treated with the standard Prostiva manufacturer-recommended protocol. The bladder neck and lateral lobes received treatment based on prostate volume and prostatic urethral length. Gadolinium-enhanced MRI sequences were obtained prior to and 1 week post-treatment. Analyze software (Mayo Clinic Biomedical Imaging Resource, Rochester, MN) was used to evaluate MRIs. New gadolinium defects were seen in all patients following Prostiva treatments. All lesions coalesced within the prostate. No defects were seen beyond the prostate, and the urethra was spared in all patients. The mean volume of necrosis was 7.56 cc, representing a mean of 11.28% of total prostate volume. Dynamic, gadolinium-enhanced MRIs demonstrate new vascular defects representing necrosis caused by Prostiva RF therapy of the prostate. The standard Prostiva RF protocol produces lesions that coalesce to create larger lesions in the bladder neck and lateral lobes. Compared to the TUNA Precision Plus device, the ablative lesions appear comparable while produced with a shorter burn time.

  12. Registration of dynamic multiview 2D ultrasound and late gadolinium enhanced images of the heart: Application to hypertrophic cardiomyopathy characterization.

    PubMed

    Betancur, Julián; Simon, Antoine; Halbert, Edgar; Tavard, François; Carré, François; Hernández, Alfredo; Donal, Erwan; Schnell, Frédéric; Garreau, Mireille

    2016-02-01

    Describing and analyzing heart multiphysics requires the acquisition and fusion of multisensor cardiac images. Multisensor image fusion enables a combined analysis of these heterogeneous modalities. We propose to register intra-patient multiview 2D+t ultrasound (US) images with multiview late gadolinium-enhanced (LGE) images acquired during cardiac magnetic resonance imaging (MRI), in order to fuse mechanical and tissue state information. The proposed procedure registers both US and LGE to cine MRI. The correction of slice misalignment and the rigid registration of multiview LGE and cine MRI are studied, to select the most appropriate similarity measure. It showed that mutual information performs the best for LGE slice misalignment correction and for LGE and cine registration. Concerning US registration, dynamic endocardial contours resulting from speckle tracking echocardiography were exploited in a geometry-based dynamic registration. We propose the use of an adapted dynamic time warping procedure to synchronize cardiac dynamics in multiview US and cine MRI. The registration of US and LGE MRI was evaluated on a dataset of patients with hypertrophic cardiomyopathy. A visual assessment of 330 left ventricular regions from US images of 28 patients resulted in 92.7% of regions successfully aligned with cardiac structures in LGE. Successfully-aligned regions were then used to evaluate the abilities of strain indicators to predict the presence of fibrosis. Longitudinal peak-strain and peak-delay of aligned left ventricular regions were computed from corresponding regional strain curves from US. The Mann-Withney test proved that the expected values of these indicators change between the populations of regions with and without fibrosis (p < 0.01). ROC curves otherwise proved that the presence of fibrosis is one factor amongst others which modifies longitudinal peak-strain and peak-delay.

  13. 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

  14. Magnetic resonance imaging of cardiac sarcoidosis: an evaluation of the cardiac segments and layers that exhibit late gadolinium enhancement

    PubMed Central

    Komada, Tomohiro; Suzuki, Kojiro; Ishiguchi, Hiroaki; Kawai, Hisashi; Okumura, Takahiro; Hirashiki, Akihiro; Naganawa, Shinji

    2016-01-01

    ABSTRACT Cardiac sarcoidosis (CS) can cause sudden death, which is the leading cause of mortality in patients with sarcoidosis in Japan. However, it is difficult to diagnose CS because of the lack of a sensitive diagnostic method for the condition. Late gadolinium-enhanced cardiac magnetic resonance (MR) imaging demonstrates improved sensitivity for diagnosing CS. Therefore, it is important to know the late gadolinium-enhancement (LGE) characteristics of CS on cardiac MR images in order to diagnose CS accurately. In this study, we investigated the most common sites of LGE on cardiac MR images in CS. Late gadolinium-enhanced MR images of 9 consecutive patients with CS (obtained between August 2009 and July 2015) were reviewed by two radiologists. The distribution of LGE was evaluated using the American Heart Association 17-segment model of the left ventricle. The LGE in each segment was also classified into 4 patterns according to the myocardial layer in which it occurred (the subepicardial, subendocardial, intramural, and transmural layer patterns). All 9 patients exhibited LGE in their left ventricle, and 70 of 153 (46%) myocardial segments were enhanced. All of the patients displayed LGE in the basal septal wall. The patients' LGE layer patterns were as follows: subepicardial: 40% (28/70), intramural: 30% (21/70), subendocardial: 16% (11/70), and transmural: 14% (10/70). The basal septum wall and subepicardial layer often exhibit LGE on cardiac MR images in CS patients. LGE can be observed in other segments and layers in some cases. PMID:28008199

  15. Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging Post-robotic Radiosurgical Pulmonary Vein Isolation (RRPVI): First Case in the World

    PubMed Central

    Azpiri, Jose; De La Peña, Cuauhtémoc; Cardona, Carlos; Hinojosa, Miguel; Zamarripa, Rafael; Assad, Jose

    2016-01-01

    Pulmonary vein isolation using robotic radiosurgery system CyberKnife is a new non-invasive treatment of atrial fibrillation, currently in clinical phase. Robotic radiosurgical pulmonary vein isolation (RRPVI) uses stereotactic, non-invasive (painless) pinpoint radiation energy delivery to a small, precise area to accomplish ablation. The purpose of this report is to describe the finding of an increase in the enhancement of the left atrium demonstrated with the use of cardiac magnetic resonance imaging using late gadolinium enhancement (LGE-CMR) as a result of RRPVI in the first case in the world in humans using CyberKnife as a treatment for paroxysmal atrial fibrillation (PAF). PMID:27660737

  16. Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging Post-robotic Radiosurgical Pulmonary Vein Isolation (RRPVI): First Case in the World.

    PubMed

    Monroy, Edgar; Azpiri, Jose; De La Peña, Cuauhtémoc; Cardona, Carlos; Hinojosa, Miguel; Zamarripa, Rafael; Assad, Jose

    2016-08-15

    Pulmonary vein isolation using robotic radiosurgery system CyberKnife is a new non-invasive treatment of atrial fibrillation, currently in clinical phase. Robotic radiosurgical pulmonary vein isolation (RRPVI) uses stereotactic, non-invasive (painless) pinpoint radiation energy delivery to a small, precise area to accomplish ablation. The purpose of this report is to describe the finding of an increase in the enhancement of the left atrium demonstrated with the use of cardiac magnetic resonance imaging using late gadolinium enhancement (LGE-CMR) as a result of RRPVI in the first case in the world in humans using CyberKnife as a treatment for paroxysmal atrial fibrillation (PAF).

  17. Gadolinium-enhanced MRI features of acute gouty arthritis on top of chronic gouty involvement in different joints.

    PubMed

    Emad, Yasser; Ragab, Yasser; El-Naggar, Ahmed; El-Shaarawy, Nashwa; Abd-Allah, Mayada A; Gamal, Rania M; Fathy, Ahmed; Hawass, Mona; Rasker, Johannes J

    2015-11-01

    The aims of the current study are to describe gadolinium-enhanced MRI features of an acute flare of established gouty arthritis in different joints and to examine a possible association between serum uric acid and MRI signs indicative of ongoing inflammation and/or structural joint damage as well as association with disease characteristics and laboratory findings. Twenty-seven male patients with established chronic gout agreed to participate, mean age 47.6 years, and mean disease duration in months 43.2 (±31.8). For all patients, detailed demographic, disease characteristics, and laboratory findings were obtained and correlated with MRI findings. In 27 patients with established gout, a total of 50 MRI studies were performed of the following joints: feet joints (n = 23), ankles (n = 18), knees (n = 5), and hand and wrist joints (n = 4). MRI revealed capsular thickening in 19 patients, bone marrow edema (BME) in 15, soft tissue edema (STE) in 20, joint effusion in 21, bone erosions in 17, cartilaginous erosions in 4, and tenosynovitis in 9 cases. In 17 cases, tophaceous lesions were found. Post contrast MRI showed synovial thickening in seven cases. Positive correlations were observed between serum uric acid levels and the following MRI findings: capsular thickening (r = 0.552, p = 0.003), BME (r = 0.668, p ≤ 0.0001), STE (r = 0.559, p = 0.002), and tenosynovitis (r = 0.513, p = 0.006). Using MRI in chronic gout, important features can be detected like BME, minute cartilaginous erosions, and hypertrophic synovial inflammation in post contrast MR images. Serum uric acid (SUA) was positively correlated with capsular thickening, BME, STE, and tenosynovitis.

  18. A novel skeleton based quantification and 3-D volumetric visualization of left atrium fibrosis using late gadolinium enhancement magnetic resonance imaging.

    PubMed

    Ravanelli, Daniele; dal Piaz, Elena Costanza; Centonze, Maurizio; Casagranda, Giulia; Marini, Massimiliano; Del Greco, Maurizio; Karim, Rashed; Rhode, Kawal; Valentini, Aldo

    2014-02-01

    This work presents the results of a new tool for 3-D segmentation, quantification and visualization of cardiac left atrium fibrosis, based on late gadolinium enhancement magnetic resonance imaging (LGE-MRI), for stratifying patients with atrial fibrillation (AF) that are candidates for radio-frequency catheter ablation. In this study 10 consecutive patients suffering AF with different grades of atrial fibrosis were considered. LGE-MRI and magnetic resonance angiography (MRA) images were used to detect and quantify fibrosis of the left atrium using a threshold and 2-D skeleton based approach. Quantification and 3-D volumetric views of atrial fibrosis were compared with quantification and 3-D bipolar voltage maps measured with an electro-anatomical mapping (EAM) system, the clinical reference standard technique for atrial substrate characterization. Segmentation and quantification of fibrosis areas proved to be clinically reliable among all different fibrosis stages. The proposed tool obtains discrepancies in fibrosis quantification less than 4% from EAM results and yields accurate 3-D volumetric views of fibrosis of left atrium. The novel 3-D visualization and quantification tool based on LGE-MRI allows detection of cardiac left atrium fibrosis areas. This noninvasive method provides a clinical alternative to EAM systems for quantification and localization of atrial fibrosis.

  19. Correlation of histological findings with gadolinium enhanced MRI scans during healing of a PHEMA orbital implant in rabbits

    PubMed Central

    Hicks, C.; Morris, I.; Vijayasekaran, S.; Fallon, M.; McAllister, J.; Clayton, A.; Chirila, T.; Crawford, G.; Constable, I.

    1999-01-01

    BACKGROUND/AIMS—To investigate a poly(2-hydroxyethyl methacrylate) (PHEMA) orbital implant with a spongy anterior hemisphere and a smooth gel posterior hemisphere, by histology correlated with magnetic resonance images.
METHODS—Following enucleation, eight rabbits received PHEMA implants to which the muscles were directly sutured, and underwent gadolinium enhanced magnetic resonance imaging (MRI) from 3 to 52 weeks. After the rabbits were killed, the implants were removed, cut in a plane corresponding to the scan, and processed for light and electron microscopy.
RESULTS—All eight rabbits retained their implant to the end of the study period without complications. The scans demonstrated muscle attachment to the anterior half of the implant, and enhancement was seen on injection of gadolinium chelate. Histology confirmed muscle attachment, and cellular and vascular ingrowth. Over time, a transformation from reactive inflammatory to relatively non-vascular scar tissue was seen within the implant. Calcium deposits in one implant were detected by imaging and histology.
CONCLUSION—The implants are readily visualised on MRI. Muscle attachment and fibrovascular ingrowth into the anterior hemisphere are seen, while encapsulation of the posterior hemisphere is minimal. Histological findings confirm the progress of the healing response, with initial inflammation and marked vascularisation, developing later into quiescent scar tissue predominantly of fibroblasts.

 PMID:10216066

  20. [Amyloid beta-related angiitis: brain lesions showing leptomeningeal gadolinium enhancement on MRI and characteristic surgical pathologic features].

    PubMed

    Koike, Yuka; Ouchi, Haruka; Sato, Tomoe; Shimbo, Junsuke; Sato, Aki; Sasaki, Osamu; Shibuya, Hiroyuki; Okamoto, Kouichirou; Kakita, Akiyoshi; Igarashi, Shuichi

    2013-06-01

    Amyloid-β-related angiitis (ABRA) of the CNS occurs in association with vasculitis of small-and medium-sized leptomeningeal arteries. Here, we describe the clinicopathological features of a 76-year-old man with ABRA. The patient suffered progressive truncal oscillation, aphasia, and recent memory disturbance with a subacute disease onset. His cerebrospinal fluid showed a mild increase in protein levels (101 mg/dL) and pleocytosis (8/mm(3)). High-intensity brain lesion were detected on T(2)-weighted and FLAIR MRI scans, and prominent spread of gadolinium enhancement spreading was observed through the sulci of the left occipital and temporal lobes and left cerebellar hemisphere. A biopsy of the left temporal lesion showed a granulomatous and angiodestructive inflammation with infiltration of many CD4(+) T-lymphocytes and multinucleated giant cells and with fibrinoid necrosis of the arterial walls in the subarachnoid space. Immunolabeling for Aβ(1-40) revealed the abundant deposition of this protein in the affected arteries. On the basic of the diagnosis of ABRA, immunosuppressive therapy was conducted, and it ameliorated the clinical course.

  1. Gadolinium Enhanced MRI Assessment of Bone-Patellar Tendon-Bone Graft Harvest on Patellar Vascularity

    PubMed Central

    Jones, Kristofer J.; Lazaro, Lionel E.; Taylor, Samuel; Pardee, Nadine C.; Dyke, Jonathan P.; Hannafin, Jo A.; Warren, Russell F.; Lorich, Dean G.

    2013-01-01

    Objectives: Bone-patellar tendon-bone (BPTB) autograft remains a favored graft source for anterior cruciate ligament (ACL) reconstruction despite problems related to donor-site morbidity. Patellar devascularization has been proposed as a source of anterior knee pain following vascular disruption from traumatic injury (fracture) or surgical procedures involving the patella (total knee arthroplasty); however, no study has investigated the effect of BPTB harvest on patellar vascularity. Recent anatomic studies have suggested that the dominant arterial supply enters the patella through the inferior pole. We hypothesized that BPTB harvest can significantly diminish patellar vascularity following graft harvest. Methods: Nine matched pair cadaveric knee specimens (mean age 47.4 years) were dissected and cannulated at the superficial femoral, anterior tibialis, and posterior tibialis arteries. A single knee was randomly selected to undergo bone graft harvest. The contralateral knee was left intact to serve as a control. Gadolinium (Gd-DPTA) was injected into each knee and MRI signal enhancement was quantified to determine differences in osseous uptake between the two knees. Following MRI assessment, each matched pair was injected with a urethane polymer compound and dissected to correlate vessel disruption with MRI findings. Results: Graft harvest resulted in a mean 31% (range, 7.1-69.5%) decrease in signal enhancement when compared to the matched control. MRI assessment revealed two predominant patterns of vessel entry for the dominant inferior arterial supply. In one pattern, the vessel entered the inferomedial aspect (∼7 o’clock) of the distal patellar pole and was disrupted by bone graft harvest in two matched pairs (2/9, 22%). In the second pattern, the predominant vessel entered further medial (∼8 o’clock) and was not disrupted in 7 matched pairs. The mean decrease in gadolinium uptake following disruption of the predominant vessel measured 56% (range, 42

  2. Free breathing three-dimensional late gadolinium enhancement cardiovascular magnetic resonance using outer volume suppressed projection navigators

    PubMed Central

    Menon, Rajiv G.; Miller, G.W.; Jeudy, Jean; Rajagopalan, Sanjay; Shin, Taehoon

    2017-01-01

    Purpose To develop a free-breathing, 3D late gadolinium enhancement (3D FB-LGE) cardiovascular magnetic resonance (CMR) technique and to compare it with clinically used 2D breath-hold LGE (2D BH-LGE). Methods The proposed 3D FB-LGE method consisted of inversion preparation, inversion delay, fat saturation, outer volume suppression, 1D-projection navigators, and a segmented stack of spirals acquisition. The 3D FB-LGE and 2D BH-LGE scans were performed on 29 cardiac patients. Qualitative analysis and quantitative analysis (in patients with scar) were performed. Results No significant differences were noted between the 3D FB-LGE and 2D BH-LGE datasets in terms of overall image quality score (2D: 4.69 ± 0.60 versus 3D: 4.55 ± 0.51, P = 0.46) and image artifact score (2D: 1.10 ± 0.31 versus 3D: 1.17 ± 0.38; P = 0.63). The average difference in fractional scar volume between the 3D and 2D methods was 1.9 % (n = 5). Acquisition time was significantly shorter for the 3D FB-LGE over 2D BH-LGE by a factor of 2.83 ± 0.77 (P < 0.0001). Conclusions The 3D FB-LGE is a viable option for patients, particularly in acute settings or in patients who are unable to comply with breath-hold instructions. PMID:27122450

  3. 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.

  4. 3D Late Gadolinium Enhancement in a Single Prolonged Breath-hold using Supplemental Oxygenation and Hyperventilation

    PubMed Central

    Roujol, Sébastien; Basha, Tamer A.; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H.; Kissinger, Kraig V.; Goddu, Beth; Berg, Sophie; Manning, Warren J.; Nezafat, Reza

    2013-01-01

    Purpose: To evaluate the feasibility of 3D single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Methods: Breath-hold metrics (breath-hold duration, diaphragmatic/LV position drift, and maximum variation of RR interval) without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (FOV=320×320×100 mm3, resolution=1.6×1.6×5.0 mm3, acceleration rate of 4) and a free breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semi-quantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Results: Supplemental oxygenation and hyperventilation increased the breath-hold duration (35±11 s to 58±21 s, p<0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both p>0.01). LGE images were of similar quality when compared to free breathing acquisitions but with reduced total scan time (85±22 s to 35±6 s, p<0.001). Conclusions: Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. PMID:24186772

  5. Three-dimensional speckle tracking longitudinal strain is related to myocardial fibrosis determined by late-gadolinium enhancement.

    PubMed

    Spartera, Marco; Damascelli, Anna; Mozes, Ferenc; De Cobelli, Francesco; La Canna, Giovanni

    2017-03-15

    Three-dimensional (3D) speckle tracking echocardiography (STE) is a reliable clinical tool for accurate measurements of left ventricular (LV) volumes and ejection fraction (EF). In this prospective study, we sought to identify an association between 3DSTE longitudinal strain abnormalities and areas of late gadolinium enhancement (LGE). In 50 patients (52 ± 18.5 years old) referred to our hospital for clinically indicated CMR, 3D full-volume trans-thoracic acquisitions on apical views were performed within 1 h of CMR, in order to obtain LV volumes and ejection fraction as well as global and segmental peak systolic longitudinal strain. Relative amount of fibrosis was defined based on LGE CMR with grey-scale threshold of 5 standard deviations above the mean signal intensity of the normal remote myocardium. We found a moderate positive correlation between global longitudinal strain (GLS) by 3DSTE and LGE proportion (r = 0.465, p = 0.001). The area under the receiver operating characteristic curve was 0.79. In addition, abnormal GLS could detect LGE-determined myocardial fibrosis with a sensitivity of 84.6%, a specificity of 84.8%, a positive predictive value of 69% and negative predictive value of 93%, considering an optimal GLS cut-off value of - 15.25%. Regarding 3DSTE capacity of localizing segmental LGE involvement, about 70% of LGE-positive segments presented a concomitant longitudinal strain reduction. This prospective study shows that 3DSTE longitudinal deformation is moderately associated with the extent of myocardial fibrosis, with a promising potential role in ruling out prognostically relevant fibrosis as detected by LGE.

  6. 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

  7. 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.

  8. Three-dimensional segmentation of the left ventricle in late gadolinium enhanced MR images of chronic infarction combining long- and short-axis information.

    PubMed

    Wei, Dong; Sun, Ying; Ong, Sim-Heng; Chai, Ping; Teo, Lynette L; Low, Adrian F

    2013-08-01

    Automatic segmentation of the left ventricle (LV) in late gadolinium enhanced (LGE) cardiac MR (CMR) images is difficult due to the intensity heterogeneity arising from accumulation of contrast agent in infarcted myocardium. In this paper, we present a comprehensive framework for automatic 3D segmentation of the LV in LGE CMR images. Given myocardial contours in cine images as a priori knowledge, the framework initially propagates the a priori segmentation from cine to LGE images via 2D translational registration. Two meshes representing respectively endocardial and epicardial surfaces are then constructed with the propagated contours. After construction, the two meshes are deformed towards the myocardial edge points detected in both short-axis and long-axis LGE images in a unified 3D coordinate system. Taking into account the intensity characteristics of the LV in LGE images, we propose a novel parametric model of the LV for consistent myocardial edge points detection regardless of pathological status of the myocardium (infarcted or healthy) and of the type of the LGE images (short-axis or long-axis). We have evaluated the proposed framework with 21 sets of real patient and four sets of simulated phantom data. Both distance- and region-based performance metrics confirm the observation that the framework can generate accurate and reliable results for myocardial segmentation of LGE images. We have also tested the robustness of the framework with respect to varied a priori segmentation in both practical and simulated settings. Experimental results show that the proposed framework can greatly compensate variations in the given a priori knowledge and consistently produce accurate segmentations.

  9. Feature Tracking-Derived Peak Systolic Strain Compared to Late Gadolinium Enhancement in Troponin-Positive Myocarditis: A Case-Control Study.

    PubMed

    Weigand, Justin; Nielsen, James C; Sengupta, Partho P; Sanz, Javier; Srivastava, Shubhika; Uppu, Santosh

    2016-04-01

    Cardiac magnetic resonance (CMR) assesses myocardial involvement in myocarditis (MYO). Current techniques are qualitative, subjective, and prone to interpretation error. Feature tracking (FT) analyzes myocardial strain using CMR and has not been examined in MYO. We hypothesize that regional left ventricular (LV) strain is abnormal in MYO. Regional strain by FT was compared to late gadolinium enhancement (LGE) and troponin leak as measures of myocardial involvement. This single-center, retrospective CMR study reviewed patients with clinical MYO and structurally normal hearts who underwent CMR at our institution. Young adults with normal cardiac anatomy, function, and absent LGE served as controls. MYO patients with documented troponin leak and normal global ejection fraction (EF > 50 %) were included in comparison. FT determined regional myocardial peak systolic strain (pkS) in longitudinal and circumferential distributions. T tests compared strain values between cases and controls. Receiver operating characteristic curves determined pkS values with highest sensitivity and specificity for concurrent troponin leak and LGE. FT was performed on 57 patients: 37 MYO and 20 controls. Twenty-eight cases with normal EF, and 20 control patients were included in final analysis. Nearly all cases with normal function demonstrated abnormal regional pkS (27/28, 96 %). Cases had significantly diminished pkS when compared to controls in all regions except the longitudinal 2C distribution. FT-derived longitudinal and circumferential pkS is sensitive and specific in identifying myocardial involvement, namely the presence of troponin leak and LGE. FT may be a useful adjunctive, objective measure of myocardial involvement in patients with MYO and normal LV function.

  10. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) Shows No Change in Cartilage Structural Composition after Viscosupplementation in Patients with Early-Stage Knee Osteoarthritis

    PubMed Central

    van Tiel, Jasper; Reijman, Max; Bos, Pieter K.; Hermans, Job; van Buul, Gerben M.; Bron, Esther E.; Klein, Stefan; Verhaar, Jan A. N.; Krestin, Gabriel P.; Bierma-Zeinstra, Sita M. A.; Weinans, Harrie; Kotek, Gyula; Oei, Edwin H. G.

    2013-01-01

    Introduction Viscosupplementation with hyaluronic acid (HA) of osteoarthritic (OA) knee joints has a well-established positive effect on clinical symptoms. This effect, however, is only temporary and the working mechanism of HA injections is not clear. It was suggested that HA might have disease modifying properties because of its beneficial effect on cartilage sulphated glycosaminoglycan (sGAG) content. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a highly reproducible, non-invasive surrogate measure for sGAG content and hence composition of cartilage. The aim of this study was to assess whether improvement in cartilage structural composition is detected using dGEMRIC 14 weeks after 3 weekly injections with HA in patients with early-stage knee OA. Methods In 20 early-stage knee OA patients (KLG I-II), 3D dGEMRIC at 3T was acquired before and 14 weeks after 3 weekly injections with HA. To evaluate patient symptoms, the knee injury and osteoarthritis outcome score (KOOS) and a numeric rating scale (NRS) for pain were recorded. To evaluate cartilage composition, six cartilage regions in the knee were analyzed on dGEMRIC. Outcomes of dGEMRIC, KOOS and NRS before and after HA were compared using paired t-testing. Since we performed multiple t-tests, we applied a Bonferroni-Holm correction to determine statistical significance for these analyses. Results All KOOS subscales (‘pain’, ‘symptoms’, ‘daily activities’, ‘sports’ and ’quality of life’) and the NRS pain improved significantly 14 weeks after Viscosupplementation with HA. Outcomes of dGEMRIC did not change significantly after HA compared to baseline in any of the cartilage regions analyzed in the knee. Conclusions Our results confirm previous findings reported in the literature, showing persisting improvement in symptomatic outcome measures in early-stage knee OA patients 14 weeks after Viscosupplementation. Outcomes of dGEMRIC, however, did not change after Viscosupplementation

  11. Evaluation of current algorithms for segmentation of scar tissue from late Gadolinium enhancement cardiovascular magnetic resonance of the left atrium: an open-access grand challenge

    PubMed Central

    2013-01-01

    Background Late Gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging can be used to visualise regions of fibrosis and scarring in the left atrium (LA) myocardium. This can be important for treatment stratification of patients with atrial fibrillation (AF) and for assessment of treatment after radio frequency catheter ablation (RFCA). In this paper we present a standardised evaluation benchmarking framework for algorithms segmenting fibrosis and scar from LGE CMR images. The algorithms reported are the response to an open challenge that was put to the medical imaging community through an ISBI (IEEE International Symposium on Biomedical Imaging) workshop. Methods The image database consisted of 60 multicenter, multivendor LGE CMR image datasets from patients with AF, with 30 images taken before and 30 after RFCA for the treatment of AF. A reference standard for scar and fibrosis was established by merging manual segmentations from three observers. Furthermore, scar was also quantified using 2, 3 and 4 standard deviations (SD) and full-width-at-half-maximum (FWHM) methods. Seven institutions responded to the challenge: Imperial College (IC), Mevis Fraunhofer (MV), Sunnybrook Health Sciences (SY), Harvard/Boston University (HB), Yale School of Medicine (YL), King’s College London (KCL) and Utah CARMA (UTA, UTB). There were 8 different algorithms evaluated in this study. Results Some algorithms were able to perform significantly better than SD and FWHM methods in both pre- and post-ablation imaging. Segmentation in pre-ablation images was challenging and good correlation with the reference standard was found in post-ablation images. Overlap scores (out of 100) with the reference standard were as follows: Pre: IC = 37, MV = 22, SY = 17, YL = 48, KCL = 30, UTA = 42, UTB = 45; Post: IC = 76, MV = 85, SY = 73, HB = 76, YL = 84, KCL = 78, UTA = 78, UTB = 72. Conclusions The study concludes that currently no algorithm is deemed clearly better than

  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. Correlation of left ventricular wall thickness, heart mass, serological parameters and late gadolinium enhancement in cardiovascular magnetic resonance imaging of myocardial inflammation in an experimental animal model of autoimmune myocarditis.

    PubMed

    Kromen, Wolfgang; Korkusuz, Huedayi; Korkusuz, Yuecel; Esters, Philip; Bauer, Ralf W; Huebner, Frank; Lindemayr, Sebastian; Vogl, Thomas J

    2012-12-01

    For a definitive diagnosis of myocarditis, different strategies like analysis of late gadolinium enhancement (LGE) in cardiovascular magnetic resonance imaging (CMR) up to invasive endomyocardial biopsy have been applied. The objective of the study was to investigate inflammatory changes like left ventricular wall thickening and increase of ventricular mass and to quantitatively analyse their correlation with extent and localisation of myocardial damage in CMR and with subsequent changes of serological markers in an animal model of an experimental autoimmune myocarditis (EAM). In the current study, an EAM was induced in 10 male Lewis rats, 10 rats served as control. On day 21, animals were examined with four CMR protocols to assess the extent of LGE in a 12 segment model of the rat heart. Left myocardial wall thickness and mass and histological grade of inflammation were measured to determine localisation and severity of the induced myocarditis. Depending on the CMR sequence, LGE was mostly found in the left anterior (9.6%) and left lateral (8.7%) myocardial wall segments. Wall thickness correlated with the LGE area in CMR imaging and the histopathological severity of myocarditis for the left lateral myocardial wall segment. In a similar way, the heart mass correlated to the extent of LGE for the left lateral segment. We conclude that in our animal model left ventricular wall thickness and mass reflect the severity of myocardial changes in myocarditis and that the EAM rat model is well suited for further investigations of myocarditis.

  14. 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.

  15. Dual Manganese-Enhanced and Delayed Gadolinium-Enhanced MRI Detects Myocardial Border Zone Injury in a Pig Ischemia-Reperfusion Model

    PubMed Central

    Dash, Rajesh; Chung, Jaehoon; Ikeno, Fumiaki; Hahn-Windgassen, Annett; Matsuura, Yuka; Bennett, Mihoko V.; Lyons, Jennifer K.; Teramoto, Tomohiko; Robbins, Robert C.; McConnell, Michael V.; Yeung, Alan C.; Brinton, Todd J.; Harnish, Phillip P.; Yang, Phillip C.

    2011-01-01

    Background Delayed gadolinium (Gd) enhancement MRI (DEMRI) identifies non-viable myocardium, but is non-specific and may overestimate nonviable territory. Manganese (Mn2+)-enhanced MRI (MEMRI) denotes specific Mn2+ uptake into viable cardiomyocytes. We performed a dual-contrast myocardial assessment in a porcine ischemia-reperfusion (IR) model to test the hypothesis that combined DEMRI and MEMRI will identify viable infarct border zone (BZ) myocardium in vivo. Methods and Results Sixty-minute LAD ischemia-reperfusion injury (IR) was induced in 13 adult swine. Twenty-one days post-IR, 3T cardiac MRI was performed. MEMRI was obtained after injection (0.7 cc/kg) of Mn2+ contrast agent (EVP1001-1, Eagle Vision Pharmaceutical Corp.). DEMRI was then acquired after 0.2mmol/kg Gd injection. Left ventricular (LV) mass, infarct, and function were analyzed. Subtraction of MEMRI defect from DEMRI signal identified injured border zone myocardium. Explanted hearts were analyzed by 2,3,5-triphenyltetrazolium chloride (TTC) stain and tissue electron microscopy (TEM) to compare infarct, BZ, and remote myocardium. Average LV ejection fraction was reduced (30±7%). MEMRI and DEMRI infarct volumes correlated with TTC (MEMRI: r=0.78; DEMRI: r=0.75; p<0.004). MEMRI infarct volume percentage was significantly lower than DEMRI (14±4%* vs. 23±4%; *p<0.05). BZ MEMRI SNR was intermediate to remote and core infarct SNR (7.5±2.8* vs. 13.2±3.4 and 2.9±1.6; *p<0.0001), and DEMRI BZ SNR tended to be intermediate to remote and core infarct (8.4±5.4 vs. 3.3±0.6 and 14.3±6.6; p>0.05). TEM analysis exhibited preserved cell structure in BZ cardiomyocytes despite transmural DEMRI enhancement. Conclusions Dual-contrast MEMRI-DEMRI detects BZ viability within DEMRI infarct zones. This approach may identify injured, at-risk myocardium in ischemic cardiomyopathy. PMID:21719779

  16. Complementary Prognostic Values of Stress Myocardial Perfusion and Late Gadolinium Enhancement Imaging by Cardiac Magnetic Resonance in Patients with Known or Suspected Coronary Artery Disease

    PubMed Central

    Steel, Kevin; Broderick, Ryan; Gandla, Vijay; Larose, Eric; Resnic, Frederick; Jerosch-Herold, Michael; Brown, Kenneth A.; Kwong, Raymond Y.

    2009-01-01

    BACKGROUND Recent studies have demonstrated the significant prognostic value of stress CMR myocardial perfusion imaging (CMRMPI). Apart from characterizing reversible perfusion defect (RevPD) from flow-limiting coronary stenosis, CMR late enhancement imaging (LGE) is currently the most sensitive method in detecting subendocardial infarction (MI). We therefore tested the hypothesis that, characterization of these 2 processes from coronary artery disease (CAD) by CMR can provide complementary prognostic values. Methods and Results We performed CMRMPI followed by LGE imaging on 254 patients referred with symptoms of myocardial ischemia. At a median follow up of 17 months, 49 cardiac events (MACE) occurred including 12 cardiac deaths, 16 acute myocardial infarction (MI), and 21 cardiac hospitalizations. RevPD and LGE both maintained a > 3-fold association with cardiac death or acute MI (Death/MI) when adjusted to each other and to the effects of patient age and gender (adjusted HR 3.31, P=0.02 and 3.43, P=0.01, respectively). In patients without a history of MI who had negative RevPD, LGE presence was associated with >11-fold hazards increase to Death/MI. Patients with neither RevPD nor LGE had a 98.1% negative annual event rate for Death/MI. For association with MACE, RevPD was the strongest multivariable variable in the best overall model (HR 10.92, P<0.0001). Conclusions CMR imaging provides robust risk-stratification of patients who presents with symptoms of ischemia. Characterization of RevPD and LGE by CMR provides strong and complementary prognostic implication towards cardiac death or acute MI. PMID:19770399

  17. 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.

  18. Regression of gadolinium-enhanced lesions in patients affected by neurofibromatosis type 1.

    PubMed

    Lucchetta, Marta; Manara, Renzo; Perilongo, Giorgio; Clementi, Maurizio; Trevisson, Eva

    2016-03-01

    Neurofibromatosis type I is a genetic condition with an autosomal dominant transmission characterized by neurocutaneous involvement and a predisposition to tumor development. Central nervous system manifestations include benign areas of dysmyelination and possibly hazardous glial tumors whose clinical management may result challenging. Here, we report on three patients diagnosed with Neurofibromatosis type I whose brain MRI follow-up showed the presence of gadolinium-enhancing lesions which spontaneously regressed. In none of the three cases, the lesions showed any clinical correlate and eventually presented a striking reduction in size while gadolinium enhancement disappeared despite no specific therapy administration during the follow-up. Although their nature remains undetermined, these lesions presented a benign evolution. However, they might be misdiagnosed as potentially life-threatening tumors. Hitherto, a similar behavior has been described only in scattered cases and we believe these findings may be of particular interest for the clinical management of patients affected by neurofibromatosis type I.

  19. Pulmonary fibrosis: tissue characterization using late-enhanced MRI compared with unenhanced anatomic high-resolution CT

    PubMed Central

    Lavelle, Lisa P.; Brady, Darragh; McEvoy, Sinead; Murphy, David; Gibney, Brian; Gallagher, Annika; Butler, Marcus; Shortt, Fionnula; McMullen, Marie; Fabre, Aurelie; Lynch, David A.; Keane, Michael P.; Dodd, Jonathan D.

    2017-01-01

    PURPOSE We aimed to prospectively evaluate anatomic chest computed tomography (CT) with tissue characterization late gadolinium-enhanced magnetic resonance imaging (MRI) in the evaluation of pulmonary fibrosis (PF). METHODS Twenty patients with idiopathic pulmonary fibrosis (IPF) and twelve control patients underwent late-enhanced MRI and high-resolution CT. Tissue characterization of PF was depicted using a segmented inversion-recovery turbo low-angle shot MRI sequence. Pulmonary arterial blood pool nulling was achieved by nulling main pulmonary artery signal. Images were read in random order by a blinded reader for presence and extent of overall PF (reticulation and honeycombing) at five anatomic levels. Overall extent of IPF was estimated to the nearest 5% as well as an evaluation of the ratios of IPF made up of reticulation and honeycombing. Overall grade of severity was dependent on the extent of reticulation and honeycombing. RESULTS No control patient exhibited contrast enhancement on lung late-enhanced MRI. All IPF patients were identified with late-enhanced MRI. Mean signal intensity of the late-enhanced fibrotic lung was 31.8±10.6 vs. 10.5±1.6 for normal lung regions, P < 0.001, resulting in a percent elevation in signal intensity from PF of 204.8%±90.6 compared with the signal intensity of normal lung. The mean contrast-to-noise ratio was 22.8±10.7. Late-enhanced MRI correlated significantly with chest CT for the extent of PF (R=0.78, P = 0.001) but not for reticulation, honeycombing, or coarseness of reticulation or honeycombing. CONCLUSION Tissue characterization of IPF is possible using inversion recovery sequence thoracic MRI. PMID:28067202

  20. Gadolinium-Enhanced Magnetic Resonance Angiography for Pulmonary Embolism

    PubMed Central

    Stein, Paul D.; Chenevert, Thomas L.; Fowler, Sarah E.; Goodman, Lawrence R.; Gottschalk, Alexander; Hales, Charles A.; Hull, Russell D.; Jablonski, Kathleen A.; Leeper, Kenneth V.; Naidich, David P.; Sak, Daniel J.; Sostman, H. Dirk; Tapson, Victor F.; Weg, John G.; Woodard, Pamela K.

    2011-01-01

    Background The accuracy of gadolinium-enhanced magnetic resonance pulmonary angiography and magnetic resonance venography for diagnosing pulmonary embolism has not been determined conclusively. Objective To investigate performance characteristics of magnetic resonance angiography, with or without magnetic resonance venography, for diagnosing pulmonary embolism. Design Prospective, multicenter study from 10 April 2006 to 30 September 2008. (ClinicalTrials.gov registration number: NCT00241826) Setting 7 hospitals and their emergency services. Patients 371 adults with diagnosed or excluded pulmonary embolism. Measurements Sensitivity, specificity, and likelihood ratios were measured by comparing independently read magnetic resonance imaging with the reference standard for diagnosing pulmonary embolism. Reference standard diagnosis or exclusion was made by using various tests, including computed tomographic angiography and venography, ventilation–perfusion lung scan, venous ultra-sonography, D-dimer assay, and clinical assessment. Results Magnetic resonance angiography, averaged across centers, was technically inadequate in 25% of patients (92 of 371). The proportion of technically inadequate images ranged from 11% to 52% at various centers. Including patients with technically inadequate images, magnetic resonance angiography identified 57% (59 of 104) with pulmonary embolism. Technically adequate magnetic resonance angiography had a sensitivity of 78% and a specificity of 99%. Technically adequate magnetic resonance angiography and venography had a sensitivity of 92% and a specificity of 96%, but 52% of patients (194 of 370) had technically inadequate results. Limitation A high proportion of patients with suspected embolism was not eligible or declined to participate. Conclusion Magnetic resonance pulmonary angiography should be considered only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated. Magnetic

  1. Epiphyseal and physeal cartilage: normal gadolinium-enhanced MR imaging.

    PubMed

    Li, Xiaoming; Wang, Renfa; Li, Yonggang; Tang, Lihua; Hu, Junwu; Xu, Anhui

    2005-01-01

    To evaluate the normal appearance of epiphyseal and physeal cartilage on Gadolinium (Gd)-enhanced MR imaging. The appearance and enhancement ratios of 20 proximal and distal femoral epiphyses in 10 normal piglets were analyzed on Gd-enhanced MR images. The correlation of the MR imaging appearance with corresponding histological findings of immature epiphyses was examined. Our results showed that Gd-enhanced MRI could differentiate the differences in enhancement between physeal and epiphyseal cartilage and show vascular canals within the epiphyseal cartilage. Enhanced ratios in the physeal were greater than those in the epiphyseal cartilage (P < 0.005). It is concluded that Gd-enhanced MR imaging reveals epiphyseal vascular canals and shows difference in enhancement of physeal and epiphyseal cartilage.

  2. Late central demyelination after Fischer's syndrome: MRI studies.

    PubMed Central

    Ferrer, X; Ellie, E; Larrivière, M; Deleplanque, B; Lagueny, A; Julien, J

    1993-01-01

    The case of a patient who presented with clinical, electrophysiological, and MRI evidence of central demyelination is described. The patient had been admitted to hospital for Fischer's syndrome a few years previously. The association of these two events suggests that central and peripheral myelinopathy may be related in Fischer's syndrome. PMID:8509787

  3. [Myocarditis in the differential diagnosis of cardiomyopathies. Endomyocardial biopsy or MRI?].

    PubMed

    Besler, C; Schuler, G; Lurz, P

    2015-06-01

    Myocarditis is an inflammatory disease of the heart muscle commonly caused by viral pathogens. Dilated cardiomyopathy is a major long-term sequela of myocarditis and at least in part related to post-viral immune-mediated responses. Establishing a diagnosis of myocarditis represents a major challenge because of the variable clinical picture and the lack of readily available, non-invasive diagnostic tests. In recent years, cardiac magnetic resonance imaging (cMRI) has emerged as a promising additional diagnostic tool in patients with suspected myocarditis: cMRI not only provides important insights into structural and functional abnormalities of the heart but relevant tissue pathologies can also be visualized. The diagnostic accuracy of three tissue criteria, i.e. the edema ratio, early gadolinium enhancement ratio and late gadolinium enhancement, has been characterized in several studies. Endomyocardial biopsy (EMB) is widely considered to be the reference standard for diagnosis of myocarditis. Although limited by sampling error, EMB is the only diagnostic procedure that can be used to confirm myocarditis. Laboratory analyses of EMB may provide information about specific causes of myocarditis and are, at least in part, of prognostic relevance. In a subset of patients the results of EMB may guide therapeutic decision-making. Additional efforts are needed in cardiac imaging, molecular characterization of EMB and evaluation of serum biomarkers to improve the diagnostic work-up in patients with suspected myocarditis and to identify potential novel targets for a cause-specific therapy of myocarditis.

  4. Late enhancement: a new feature in MRI of arrhythmogenic right ventricular cardiomyopathy?

    PubMed

    Hunold, Peter; Wieneke, Heinrich; Bruder, Oliver; Krueger, Ulrich; Schlosser, Thomas; Erbel, Raimund; Barkhausen, Jörg

    2005-01-01

    Aim of the study was to evaluate whether late enhancement (LE) in contrast-enhanced MRI can be used to characterize fibrofatty myocardial replacement in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC). Fifteen patients with suspected ARVC underwent CE-MRI using a 1.5 T scanner. Long and short axis SSFP cine images and T1-weighted fast spin echo images were collected in all patients. After injection of 0.2 mmol/kg Gd-DTPA (Magnevist, Schering, Berlin, Germany), inversion recovery gradient echo images were acquired in long and contiguous short axes to detect myocardial LE indicating areas of fibrous tissue within the myocardium. For definition of ARVC, the ESC Task force criteria were used. In 7 (47%) of 15 patients, ARVC was diagnosed based on the ESC criteria. In all of these 7 patients, MRI showed morphologic or functional criteria of ARVC according to the ESC. LE of the right ventricular myocardium was detected in 5 (71%) of the 7 ARVC patients, additional LE of the left ventricular myocardium in 2 of these patients. None of the 7 patients meeting the ARVC diagnostic criteria had fatty RV infiltration demonstrable by conventional T1-weighted imaging. Eight patients neither showed morphologic criteria of ARVC nor LE. In conclusion, late enhancement can be detected in the right and left ventricular myocardium in some ARVC patients. LE might represent intramyocardial areas of fibrous tissue.

  5. 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.

  6. Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla.

    PubMed

    Kelle, Sebastian; Schlendorf, Kelly; Hirsch, Glenn A; Gerstenblith, Gary; Fleck, Eckart; Weiss, Robert G; Stuber, Matthias

    2010-10-11

    Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd) contrast administration and coronary vessel wall enhancement (LGE) detected by 3T magnetic resonance imaging (MRI) in healthy subjects and patients with coronary artery disease (CAD). Materials and Methods. Four healthy subjects (4 men, mean age 29 ± 3 years and eleven CAD patients (6 women, mean age 61 ± 10 years) were studied on a commercial 3.0 Tesla (T) whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands). T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI) was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd) (0.1 mmol/kg Gd-DTPA). Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3%) segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0%) and at time-interval 3, 29 of 39 evaluable segments (74.4%) were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30-45 minutes after administration of the contrast agent.

  7. Diagnosis of Paracardiac Castleman Disease by Dynamic Gadolinium-Enhanced First Pass Perfusion Magnetic Resonance Imaging

    PubMed Central

    Crean, Andrew; Paul, Narinder; Merchant, Naeem; Singer, Lianne; Provost, Yves

    2008-01-01

    Summary Castleman disease is an uncommon disorder affecting the lymphatic system and is characterised by atypical lymphocyte proliferation. The usual clinical presentation is of a solitary mass lesion, frequently within the thorax. A number of different imaging findings have been reported on CT and MRI. We present a case of paracardiac Castleman disease where the diagnosis was suggested by dramatic enhancement of the tumour mass during a dynamic MR perfusion sequence. To our knowledge this is the first report of the use of a first pass bolus tracking technique in the diagnosis of Castleman disease. PMID:24179362

  8. Language lateralisation in late proficient bilinguals: a lexical decision fMRI study.

    PubMed

    Park, Haeme R P; Badzakova-Trajkov, Gjurgjica; Waldie, Karen E

    2012-04-01

    Approximately half the world's population can now speak more than one language. Understanding the neural basis of language organisation in bilinguals, and whether the cortical networks involved during language processing differ from that of monolinguals, is therefore an important area of research. A main issue concerns whether L2 (second language) is processed using the same neural mechanisms that mediate L1 (first language) processing. Moderating factors include the age of L2 acquisition and the level of proficiency. Here we used a lexical decision task with five conditions during functional magnetic resonance imaging (fMRI) to investigate language processing in eight late proficient bilinguals when using Macedonian (L1) and English (L2). Bilinguals had greater bilateral activation during both L1 and L2 processing, and therefore weaker language lateralisation, compared to matched control English monolinguals. A greater amount of overall activation was also seen in bilinguals, especially during L2 conditions. Late proficient bilinguals living in their L2 environment employ a more extensive neural network than monolinguals when processing their second language.

  9. 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.

  10. Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets.

    PubMed

    Li, Xiaoming; Wang, Renfa; Qi, Jianpin; Tang, Lihua

    2005-01-01

    The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

  11. Three-dimensional gadolinium-enhanced magnetic resonance angiography used as a "one-stop shop'' imaging procedure for venous thromboembolism: a pilot study.

    PubMed

    Obernosterer, Andrea; Aschauer, Manuela; Portugaller, Horst; Köppel, Herwig; Lipp, Rainer W

    2005-01-01

    Pulmonary embolism and deep venous thrombosis are individual manifestations of a single entity, venous thromboembolic disease. This study aimed to assess the feasibility of 3-dimensional gadolinium-enhanced magnetic resonance angiography used as an "one-stop shop'' imaging procedure visualizing both the pulmonary arteries and the deep lower venous system within a single investigation. The inclusion criterion was a proven or excluded venous thromboembolism. Diagnosis was based on an imaging work-up for pulmonary embolism including either perfusion lung scan or contrast-enhanced spiral computed tomography, or both, and an imaging work-up for deep venous thrombosis including either venous color-coded duplex sonography or ascending phlebography, or both. A gadolinium-enhanced "one-stop shop'' magnetic resonance angiography was performed within 24 hours of completed diagnostic imaging work-up for pulmonary embolism and deep venous thrombosis in 20 patients. Results of pulmonary magnetic resonance angiography were concordant with perfusion lung scan and/or computed tomography in 90% of patients. Magnetic resonance angiography results of the deep lower venous system were concordant with venous duplex sonography and/or phlebography in 75% of patients and seemed to be more precise in 25% of patients. The "one-stop shop'' imaging procedure using gadolinium-enhanced magnetic resonance angiography was feasible and proved to offer a reliable and rapid diagnostic approach in thromboembolic disease, sparing patients' exposure to ionizing radiation and iodinated contrast media.

  12. Biventricular apical thrombi demonstrated by contrast-enhanced cardiac MRI following anteroapical STEMI and unsuccessful reperfusion therapy

    PubMed Central

    Keeble, William; VonderMuhll, Isabelle; Paterson, Ian

    2008-01-01

    Contrast-enhanced cardiac magnetic resonance imaging can define the territory and extent of myocardial infarction from patterns of late gadolinium enhancement. Following failure to reperfuse with thrombolytic therapy, a case of myocardial infarction is described in which ongoing symptoms and an electrocardiogram change led to a diagnostic dilemma. Cardiac magnetic resonance imaging confirmed an apical infarction, an aneurysm and acute pericarditis. In addition, late gadolinium enhancement unexpectedly revealed the presence of biventricular apical thrombi. The prevalence of cardiac thrombi and pulmonary emboli may be greater than generally appreciated. PMID:18685749

  13. 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.

  14. Tailored management of atrial fibrillation using a LGE-MRI based model: from the clinic to the electrophysiology laboratory.

    PubMed

    Vergara, Gaston R; Marrouche, Nassir F

    2011-04-01

    Ablation provides a good therapeutic alternative for atrial fibrillation (AF) management; however, its effectiveness relies in adequate patient selection. Late gadolinium enhancement-magnetic resonance imaging (LGE-MRI) allows for atrial arrhythmic substrate, as well as postablation scarring visualization. In this article, we describe a new staging system for AF based on the amount of left atrial enhancement on LGE-MRI (Utah I ≤ 5%, Utah II >5-20%, Utah III > 20-35%, and Utah IV > 35%). On the basis of patient stage, a more tailored approach to AF management can be taken. This includes triaging appropriate candidates for ablation (Utah stages I-III), as well as anticoagulation management based on an increase on the predictive statistics of the CHADS(2). LGE-MRI also allows for ablation lesion characterization. Acute edema, defined as enhancement on T2-weighted MRI images immediately post-AF ablation correlates with low voltage areas but not with LGE-MRI-defined scar. Post-AF ablation LGE-MRI scans show significant heterogeneity in the atrial wall on portions subject to radiofrequency (RF). We have postulated that some of these areas correspond to no-reflow type phenomenon. Postablation LGE-MRI can also help identify breaks in lesion sets and its correlation with conduction recovery has been used successfully to guide redo procedures. Real-time MRI-based ablation system has the potential advantage of tissue lesion visualization during RF delivery. To that end, we have developed a 3-Tesla-based real-time MRI ablation system. We demonstrated the feasibility to safely navigate, pace, and record intracardiac EGMs in the atrial chambers, as well as applying RF energy while directly visualizing lesion formation in real time. 

  15. MRI evaluation of injectable hyaluronic acid-based hydrogel therapy to limit ventricular remodeling after myocardial infarction.

    PubMed

    Dorsey, Shauna M; McGarvey, Jeremy R; Wang, Hua; Nikou, Amir; Arama, Leron; Koomalsingh, Kevin J; Kondo, Norihiro; Gorman, Joseph H; Pilla, James J; Gorman, Robert C; Wenk, Jonathan F; Burdick, Jason A

    2015-11-01

    Injectable biomaterials are an attractive therapy to attenuate left ventricular (LV) remodeling after myocardial infarction (MI). Although studies have shown that injectable hydrogels improve cardiac structure and function in vivo, temporal changes in infarct material properties after treatment have not been assessed. Emerging imaging and modeling techniques now allow for serial, non-invasive estimation of infarct material properties. Specifically, cine magnetic resonance imaging (MRI) assesses global LV structure and function, late-gadolinium enhancement (LGE) MRI enables visualization of infarcted tissue to quantify infarct expansion, and spatial modulation of magnetization (SPAMM) tagging provides passive wall motion assessment as a measure of tissue strain, which can all be used to evaluate infarct properties when combined with finite element (FE) models. In this work, we investigated the temporal effects of degradable hyaluronic acid (HA) hydrogels on global LV remodeling, infarct thinning and expansion, and infarct stiffness in a porcine infarct model for 12 weeks post-MI using MRI and FE modeling. Hydrogel treatment led to decreased LV volumes, improved ejection fraction, and increased wall thickness when compared to controls. FE model simulations demonstrated that hydrogel therapy increased infarct stiffness for 12 weeks post-MI. Thus, evaluation of myocardial tissue properties through MRI and FE modeling provides insight into the influence of injectable hydrogel therapies on myocardial structure and function post-MI.

  16. Contrast-enhanced cardiac MRI before coronary artery bypass surgery: impact of myocardial scar extent on bypass flow.

    PubMed

    Hunold, Peter; Massoudy, Parwis; Boehm, Claudia; Schlosser, Thomas; Nassenstein, Kai; Knipp, Stephan; Eggebrecht, Holger; Thielmann, Matthias; Erbel, Raimund; Jakob, Heinz; Barkhausen, Jörg

    2008-12-01

    The aim of the study was to relate the extent of myocardial late gadolinium enhancement (LGE) in cardiac MRI to intraoperative graft flow in patients undergoing coronary artery bypass graft (CABG) surgery. Thirty-three CAD patients underwent LGE MRI before surgery using an inversion-recovery GRE sequence (turboFLASH). Intraoperative graft flow in Doppler ultrasonography was compared with the scar extent in each coronary vessel territory. One hundred and fourteen grafts were established supplying 86 of the 99 vessel territories. A significant negative correlation was found between scar extent and graft flow (r = -0.4, p < 0.0001). Flow in grafts to territories with no or small subendocardial scar was significantly higher than in grafts to territories with broad nontransmural or transmural scar (75 +/- 39 vs. 38 +/- 26 cc min(-1); p < 0.0001). In summary, the extent of myocardial scar as defined by contrast-enhanced MRI predicts coronary bypass graft flow. Beyond the probability of functional recovery, preoperative MRI might add value to surgery planning by predicting midterm bypass graft patency.

  17. MRI Evaluation of Injectable Hyaluronic Acid-Based Hydrogel Therapy to Limit Ventricular Remodeling after Myocardial Infarction

    PubMed Central

    Dorsey, Shauna M.; McGarvey, Jeremy R.; Wang, Hua; Nikou, Amir; Arama, Leron; Koomalsingh, Kevin J.; Kondo, Norihiro; Gorman, Joseph H.; Pilla, James J.; Gorman, Robert C.; Wenk, Jonathan F.; Burdick, Jason A.

    2015-01-01

    Injectable biomaterials are an attractive therapy to attenuate left ventricular (LV) remodeling after myocardial infarction (MI). Although studies have shown that injectable hydrogels improve cardiac structure and function in vivo, temporal changes in infarct material properties after treatment have not been assessed. Emerging imaging and modeling techniques now allow for serial, non-invasive estimation of infarct material properties. Specifically, cine MRI assesses global LV structure and function, late-gadolinium enhancement (LGE) MRI enables visualization of infarcted tissue to quantify infarct expansion, and spatial modulation of magnetization (SPAMM) tagging provides passive wall motion assessment as a measure of tissue strain, which can all be used to evaluate infarct properties when combined with finite element (FE) models. In this work, we investigated the temporal effects of degradable hyaluronic acid (HA) hydrogels on global LV remodeling, infarct thinning and expansion, and infarct stiffness in a porcine infarct model for 12 weeks post-MI using MRI and FE modeling. Hydrogel treatment led to decreased LV volumes, improved ejection fraction, and increased wall thickness when compared to controls. FE model simulations demonstrated that hydrogel therapy increased infarct stiffness for 12 weeks post-MI. Thus, evaluation of myocardial tissue properties through MRI and FE modeling provides insight into the influence of injectable hydrogel therapies on myocardial structure and function post-MI. PMID:26280951

  18. Functional Imaging: CT and MRI

    PubMed Central

    van Beek, Edwin JR; Hoffman, Eric A

    2008-01-01

    Synopsis Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled MDCT allow for quantification of presence and distribution of parenchymal and airway pathology, Xenon gas can be employed to assess regional ventilation of the lungs and rapid bolus injections of iodinated contrast agent can provide quantitative measure of regional parenchymal perfusion. Advances in magnetic resonance imaging (MRI) of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized helium imaging, which can allow imaging of pulmonary ventilation and .measurement of the size of emphysematous spaces. PMID:18267192

  19. Adaptive changes in early and late blind: a fMRI study of Braille reading.

    PubMed

    Burton, H; Snyder, A Z; Conturo, T E; Akbudak, E; Ollinger, J M; Raichle, M E

    2002-01-01

    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

  20. MRI-Based Classification Models in Prediction of Mild Cognitive Impairment and Dementia in Late-Life Depression

    PubMed Central

    Lebedeva, Aleksandra K.; Westman, Eric; Borza, Tom; Beyer, Mona K.; Engedal, Knut; Aarsland, Dag; Selbaek, Geir; Haberg, Asta K.

    2017-01-01

    Objective: Late-life depression (LLD) is associated with development of different types of dementia. Identification of LLD patients, who will develop cognitive decline, i.e., the early stage of dementia would help to implement interventions earlier. The purpose of this study was to assess whether structural brain magnetic resonance imaging (MRI) in LLD patients can predict mild cognitive impairment (MCI) or dementia 1 year prior to the diagnosis. Methods: LLD patients underwent brain MRI at baseline and repeated clinical assessment after 1-year. Structural brain measurements were obtained using Freesurfer software (v. 5.1) from the T1W brain MRI images. MRI-based Random Forest classifier was used to discriminate between LLD who developed MCI or dementia after 1-year follow-up and cognitively stable LLD. Additionally, a previously established Random Forest model trained on 185 patients with Alzheimer’s disease (AD) vs. 225 cognitively normal elderly from the Alzheimer’s disease Neuroimaging Initiative was tested on the LLD data set (ADNI model). Results: MCI and dementia diagnoses were predicted in LLD patients with 76%/68%/84% accuracy/sensitivity/specificity. Adding the baseline Mini-Mental State Examination (MMSE) scores to the models improved accuracy/sensitivity/specificity to 81%/75%/86%. The best model predicted MCI status alone using MRI and baseline MMSE scores with accuracy/sensitivity/specificity of 89%/85%/90%. The most important region for all the models was right ventral diencephalon, including hypothalamus. Its volume correlated negatively with the number of depressive episodes. ADNI model trained on AD vs. Controls using SV could predict MCI-DEM patients with 67% accuracy. Conclusion: LDD patients developing MCI and dementia can be discriminated from LLD patients remaining cognitively stable with good accuracy based on baseline structural MRI alone. Baseline MMSE score improves prediction accuracy. Ventral diencephalon, including the hypothalamus

  1. MRI-Based Classification Models in Prediction of Mild Cognitive Impairment and Dementia in Late-Life Depression.

    PubMed

    Lebedeva, Aleksandra K; Westman, Eric; Borza, Tom; Beyer, Mona K; Engedal, Knut; Aarsland, Dag; Selbaek, Geir; Haberg, Asta K

    2017-01-01

    Objective: Late-life depression (LLD) is associated with development of different types of dementia. Identification of LLD patients, who will develop cognitive decline, i.e., the early stage of dementia would help to implement interventions earlier. The purpose of this study was to assess whether structural brain magnetic resonance imaging (MRI) in LLD patients can predict mild cognitive impairment (MCI) or dementia 1 year prior to the diagnosis. Methods: LLD patients underwent brain MRI at baseline and repeated clinical assessment after 1-year. Structural brain measurements were obtained using Freesurfer software (v. 5.1) from the T1W brain MRI images. MRI-based Random Forest classifier was used to discriminate between LLD who developed MCI or dementia after 1-year follow-up and cognitively stable LLD. Additionally, a previously established Random Forest model trained on 185 patients with Alzheimer's disease (AD) vs. 225 cognitively normal elderly from the Alzheimer's disease Neuroimaging Initiative was tested on the LLD data set (ADNI model). Results: MCI and dementia diagnoses were predicted in LLD patients with 76%/68%/84% accuracy/sensitivity/specificity. Adding the baseline Mini-Mental State Examination (MMSE) scores to the models improved accuracy/sensitivity/specificity to 81%/75%/86%. The best model predicted MCI status alone using MRI and baseline MMSE scores with accuracy/sensitivity/specificity of 89%/85%/90%. The most important region for all the models was right ventral diencephalon, including hypothalamus. Its volume correlated negatively with the number of depressive episodes. ADNI model trained on AD vs. Controls using SV could predict MCI-DEM patients with 67% accuracy. Conclusion: LDD patients developing MCI and dementia can be discriminated from LLD patients remaining cognitively stable with good accuracy based on baseline structural MRI alone. Baseline MMSE score improves prediction accuracy. Ventral diencephalon, including the hypothalamus

  2. 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.

  3. Leptomeningeal metastasis from gynecologic cancers diagnosed by brain MRI.

    PubMed

    Toyoshima, Masafumi; Tsuji, Keita; Shigeta, Shogo; Tokunaga, Hideki; Ito, Kiyoshi; Watanabe, Yoh; Yoshinaga, Kosuke; Otsuki, Takeo; Niikura, Hitoshi; Yaegashi, Nobuo

    Leptomeningeal metastasis (LM) is rarely observed in gynecologic cancers. As gadolinium-enhanced magnetic resonance imaging (Gd-MRI) is highly effective for diagnosing LM, the aim of this study is to describe the clinical behaviors and outcomes of LM patients who were diagnosed by Gd-MRI. After securing institutional review board approvals, we retrospectively reviewed patient records. Eight patients were found to have LM from gynecological malignancies. Primary tumors included three ovarian cancers, one tubal cancer, one peritoneal cancer, two endometrial cancers, and one cervical cancer. Gd-MRI of the brain and the spine is indicated as the high-priority inspection for the diagnosis of this devastating complication.

  4. Diagnosis of early-stage rheumatoid arthritis: usefulness of unenhanced and gadolinium-enhanced MR images at 3 T.

    PubMed

    Aoki, Takatoshi; Yamashita, Yoshiko; Saito, Kazuyoshi; Tanaka, Yoshiya; Korogi, Yukunori

    2013-01-01

    Forty-one consecutive unclassified arthritis patients with polyarthralgia including wrist joint were evaluated with 3-T MRI as possible early-stage rheumatoid arthritis (RA). After prospective follow-up, 21 of 41 patients fulfilled the American College of Rheumatology (ACR) criteria. Synovitis was detected in all 21 RA patients (sensitivity=100%) with postcontrast MRI and in 14 patients (67%) with unenhanced MRI when none of them fulfilled ACR diagnostic criteria. Fat-suppressed intermediate-weighted fast spin-echo (FSE) image showed high detection rate of synovitis and bone erosion, whereas FIESTA image clearly delineated joint fluid and bone trabeculae. MRI at 3 T is a potentially powerful tool for discriminating and managing early-stage RA patients.

  5. 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.

  6. Late cranial MRI after cranial irradiation in survivors of childhood cancer.

    PubMed

    Pääkkö, E; Talvensaari, K; Pyhtinen, J; Lanning, M

    1994-11-01

    We carried out MRI on 43 survivors of childhood cancer after different treatment protocols with or without cranial radiotherapy. They were free of disease, therapy having been discontinued 2-20 years earlier. Treatment had been for various malignancies, excluding brain tumours; 27 had received cranial irradiation for acute lymphoblastic leukaemia (ALL) or lymphoma. Two asymptomatic young women treated for ALL had falx meningiomas. White matter changes, low intensity foci (representing calcification or old haemorrhage) and heterogeneous intensity focic old haemorrhages) were seen only in patients who had undergone radiotherapy. Because of the possibility of benign, potentially curable brain tumours occurring after cranial irradiation, it may be wise to carry out occasional cranial imaging in the follow-up of these patients. No routine imaging follow-up is needed after chemotherapy alone.

  7. MRI of osteoarthritis: the challenges of definition and quantification.

    PubMed

    Hayashi, Daichi; Guermazi, Ali; Roemer, Frank W

    2012-11-01

    The ability of MRI to visualize the joint as a "whole organ" and to directly and three-dimensionally assess cartilage morphology and composition has given it a crucial role in discovering the natural history of osteoarthritis (OA). Morphological analysis can be semiquantitative or quantitative. Compositional analysis such as delayed gadolinium-enhanced MRI of cartilage and T2 mapping allows quantitative evaluation of tissue ultrastructure and can detect premorphological changes of cartilage and other tissues. Contrast-enhanced MRI can accurately assess the true extent of synovial inflammation. Most MRI-based studies so far have focused on knee OA, but with the availability of new semiquantitative scoring systems for hand and hip OA, studies of these joints have begun to appear. Because of the technical complexity of MRI and ever increasing number of new and sophisticated imaging sequences and protocols, the specific MRI technique in any OA study needs to be carefully tailored to the aims of the study.

  8. A challenging diagnosis of late-onset tumefactive multiple sclerosis associated to cervicodorsal syringomyelia: doubtful CT, MRI, and bioptic findings

    PubMed Central

    Conforti, Renata; Capasso, Raffaella; Galasso, Rosario; Cirillo, Mario; Taglialatela, Gemma; Galasso, Luigi

    2016-01-01

    Abstract Background: Tumefactive multiple sclerosis (MS) is an unusual variant of demyelinating disease characterized by lesions with pseudotumoral appearance on radiological imaging mimicking other space-occupying lesions, such as neoplasms, infections, and infarction. Especially when the patient's medical history is incompatible with MS, the differential diagnosis between these lesions constitutes a diagnostic challenge often requiring histological investigation. An older age at onset makes distinguishing tumefactive demyelinating lesion (TDL) from tumors even more challenging. Methods: We report a case of brain TDL as the initial manifestation of late-onset MS associated with cervico-dorsal syringomyelia. A 66-year-old Caucasian woman with a 15-day history headache was referred to our hospital because of the acute onset of paraphasia. She suffered from noncommunicating syringomyelia associated to basilar impression and she reported a 10-year history of burning dysesthesia of the left side of the chest extended to the internipple line level. Results: Computed tomography (CT) and magnetic resonance imaging (MRI) examinations revealed a left frontal lesion with features suspicious for a tumor. Given the degree of overlap with other pathologic processes, CT and MRI findings failed to provide an unambiguous diagnosis; furthermore, because of the negative cerebrospinal fluid analysis for oligoclonal bands, the absence of other lesions, and the heightened suspicion of neoplasia, the clinicians opted to perform a stereotactic biopsy. Brain specimen analysis did not exclude the possibility of perilesional reactive gliosis and the patient, receiving anitiedemigen therapy, was monthly followed up. In the meanwhile, the second histological opinion of the brain specimen described the absence of pleomorphic glial cells indicating a tumor. These findings were interpreted as destructive inflammatory demyelinating disease and according to the evolution of MRI lesion burden, MS

  9. Gadolinium-enhanced T1-weighted versus T2-weighted imaging of scrotal disorders: is there an indication for MR imaging?

    PubMed

    Müller-Leisse, C; Bohndorf, K; Stargardt, A; Sohn, M; Neuerburg, J; Adam, G; Wein, B; Urhahn, R; Günther, R W

    1994-01-01

    To evaluate the use of gadopentetate dimeglumine in magnetic resonance (MR) imaging of scrotal disorders, the clinical, ultrasound, and MR imaging data of 29 patients (age range, 19-75 years) with various intra- and extratesticular disorders were retrospectively analyzed. T1- and T2-weighted spin-echo images (T1-T2 group) were compared with T1-weighted spin-echo images before and after intravenous administration of gadopentetate dimeglumine (T1-Gd group). A receiver operating characteristic (ROC) analysis of the findings was undertaken. Better contrast between tumor and parenchyma and a clearer demonstration of the tunica albuginea were noted in the T1-T2 group (although not of diagnostic relevance). ROC analysis revealed no differences between the two imaging groups in the diagnosis of tumor, trauma, hydrocele, or hemorrhage; however, epididymitis was diagnosed more easily with contrast enhancement (0.8834 vs 0.7759, P = .04) and the diagnosis of orchitis was expressed more strongly (0.8221 vs 0.7184, P = .17). Four of the five observers were more confident in making the diagnosis with contrast enhancement. With MR imaging, the diagnosis was correctly suggested in three patients in whom clinical and ultrasound data were inconclusive. Gadolinium-enhanced MR imaging gives additional information in scrotal disorders and facilitates diagnosis. It may be helpful when findings at physical examination and ultrasound differ and when plain T1- and T2-weighted images are equivocal.

  10. Emotional perception: Correspondence of early and late event-related potentials with cortical and subcortical functional MRI

    PubMed Central

    Sabatinelli, Dean; Keil, Andreas; Frank, David W.; Lang, Peter J.

    2012-01-01

    Using a picture perception task, here we investigate the relationship of early occipitotemporal and later centroparietal emotion-modulated event-related potentials (ERPs) in one sample to functional magnetic resonance imaging (fMRI) estimates of neural activity in another sample in a replicated experiment. Using this approach, we aimed to link effects found in time-resolved electrocortical measures to specific cerebral structures across individual emotional and nonemotional picture stimuli. The centroparietal late positive potential (LPP) showed covariation with emotion-modulated regions of hemodynamic activation across multiple dorsal and ventral visual cortical structures, while the early occipitotemporal potential was not reliably associated. Subcortical and corticolimbic structures involved in the perception of motivationally relevant stimuli also related to modulation of the LPP, and were modestly associated to the amplitude of the early occipitotemporal potential. These data suggest that early occipitotemporal potentials may reflect multiple sources of modulation including motivational relevance, and supports the perspective that the slow-wave LPP represents aggregate cortical and subcortical structures involved in emotional discrimination. PMID:22560889

  11. Gray matter changes in late life depression--a structural MRI analysis.

    PubMed

    Andreescu, Carmen; Butters, Meryl A; Begley, Amy; Rajji, Tarek; Wu, Minjie; Meltzer, Carolyn C; Reynolds, Charles F; Aizenstein, Howard

    2008-10-01

    Multiple brain morphometric changes have been reported in late-life depression (LLD), mostly in studies comparing volumes of circumscribed brain areas. The aim of our study is to characterize the volumetric changes of multiple gray matter regions in relation to age of onset/duration of illness. We predicted that the association of gray matter volumes with total duration of illness and age of onset would differ depending on whether the region was susceptible to the toxic effects of chronic exposure to cortisol or to the vascular/neurodegenerative changes accompanying prodromal dementia. Seventy-one elderly depressed subjects were studied along with thirty-two comparison subjects. High-resolution T1-weighted brain MRIs were processed using an automated labeling pathway technique. To protect against type-I error, we combined the right and left hemisphere volume data. We sampled 24 regions of interest (ROIs). We used the primary visual cortex volume to normalize for individual variations in brain size. LLD Subjects had smaller volumes than non-depressed subjects in 17 of the 24 examined ROIs. Shorter duration of illness and later age of onset was correlated with smaller volumes of parahippocampal area and parietal inferior area. A later age of onset was also correlated with smaller volumes of several frontal and temporal areas, cingulum, and putamen. Our findings support a dementia prodrome model more strongly than a toxic stress model in this group of subjects. However, it remains likely that both processes as well as other factors contribute to the heterogeneity of volumetric brain changes in LLD.

  12. 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.

  13. FDG PET/CT in Early and Late Stages of SAPHO Syndrome: Two Case Reports With MRI and Bone Scintigraphy Correlation.

    PubMed

    Dong, Aisheng; Bai, Yushu; Cui, Yong; Zhang, Jian; Zuo, Changjing

    2016-04-01

    Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare disease, which may be underdiagnosed or misdiagnosed because of nonspecific clinical and imaging findings. We present 2 cases of SAPHO syndrome with MRI, bone scintigraphy, and FDG PET/CT findings. In case 1 with early-stage disease, the active osteitis showed osteolytic bone destruction with increased FDG uptake. In case 2 with late-stage disease, the inactive bone lesions presented as osteosclerosis with normal FDG uptake. Familiarity with the FDG PET/CT findings of SAPHO syndrome in different stages may be helpful for correct diagnosis.

  14. An experimental study on use of 7T MRI for evaluation of myocardial infarction in SD rats transfected with pcDNA 3.1(+)/VEGF121 plasmid

    PubMed Central

    Zhang, Yan; Tian, Ruiqing; Shen, Xiangchun; Chen, Yushu; Chen, Wei; Gan, Lu; Shen, Guiquan; Ju, Haiyue; Yang, Li; Gao, Fabao

    2016-01-01

    This study aims to build the myocardial infarction model in SD rats transfected with pcDNA 3.1(+)/VEGF121 plasmid and study the effect of the transfection using 7T MRI. Twenty-four male SD rats were randomly divided into 2 groups, pcDNA 3.1(+)/VEGF121 plasmid transfection group (with improved coronary perfusion delivery) and myocardial infarction model group. Cardiac cine magnetic resonance imaging (Cine-MRI), T2-mapping and late gadolinium enhancement (LGE) cardiac imaging were performed at 24 h, 48 h, 72 h and 7 d after myocardial infarction, respectively. The signal intensity, area at risk (AAR), myocardium infarction core (MIC) and salvageable myocardial zone (SMZ) were compared. The hearts were harvested for anatomic characterization, which was related to pathological examination (TTC staining, HE staining, Masson staining and immunohistochemical staining). The Cine-MRI results showed that pcDNA 3.1(+)/VEGF121 plasmid transfection group had higher end-diastolic volume (EDV) with a reduction in MIC and SMZ, as compared with the myocardial infarction model group. MIC, SMZ and AAR of the plasmid transfection declined over time. At 7 d, the two groups did not differ significantly in AAR and T2 value. According to Western Blotting, VEGF was up-regulated, while CaSR and caspase-3 were downregulated in the plasmid transfection group, as compared with the model group. In conclusion, a good treatment effect was achieved by coronary perfusion of pcDNA 3.1(+)/VEGF121 plasmid. 7T CMR sequences provide a non-invasive quantification of the treatment efficacy. However, the assessment of myocardial injury using T2 value and AAR in the presence of edema is less accurate. The myocardial protection of the plasmid transfection group may be related to the inhibition of myocardial apoptosis, vascular endothelial cell (VEC) proliferation and collagen proliferation. The CaSR signaling pathway may contribute to reversing the apoptosis. PMID:27648128

  15. Evaluation of negative fixed-charge density in tissue-engineered cartilage by quantitative MRI and relationship with biomechanical properties.

    PubMed

    Miyata, Shogo; Homma, Kazuhiro; Numano, Tomokazu; Tateishi, Tetsuya; Ushida, Takashi

    2010-07-01

    Applying tissue-engineered cartilage in a clinical setting requires noninvasive evaluation to detect the maturity of the cartilage. Magnetic resonance imaging (MRI) of articular cartilage has been widely accepted and applied clinically in recent years. In this study, we evaluated the negative fixed-charge density (nFCD) of tissue-engineered cartilage using gadolinium-enhanced MRI and determined the relationship between nFCD and biomechanical properties. To reconstruct cartilage tissue, articular chondrocytes from bovine humeral heads were embedded in agarose gel and cultured in vitro for up to 4 weeks. The nFCD of the cartilage was determined using the MRI gadolinium exclusion method. The equilibrium modulus was determined using a compressive stress relaxation test, and the dynamic modulus was determined by a dynamic compression test. The equilibrium compressive modulus and dynamic modulus of the tissue-engineered cartilage increased with an increase in culture time. The nFCD value--as determined with the [Gd-DTPA(2-)] measurement using the MRI technique--increased with culture time. In the regression analysis, nFCD showed significant correlations with equilibrium compressive modulus and dynamic modulus. From these results, gadolinium-enhanced MRI measurements can serve as a useful predictor of the biomechanical properties of tissue-engineered cartilage.

  16. Correlation of Scar in Cardiac MRI and High‐Resolution Contact Mapping of Left Ventricle in a Chronic Infarct Model

    PubMed Central

    THAJUDEEN, ANEES; STEWART, BRIAN; COKIC, IVAN; NAKAGAWA, HIROSHI; SHEHATA, MICHAEL; AMORN, ALLEN M.; KALI, AVINASH; LIU, EZH; HARLEV, DORON; BENNETT, NATHAN; DHARMAKUMAR, ROHAN; CHUGH, SUMEET S.; WANG, XUNZHANG

    2015-01-01

    Background Endocardial mapping for scars and abnormal electrograms forms the most essential component of ventricular tachycardia ablation. The utility of ultra‐high resolution mapping of ventricular scar was assessed using a multielectrode contact mapping system in a chronic canine infarct model. Methods Chronic infarcts were created in five anesthetized dogs by ligating the left anterior descending coronary artery. Late gadolinium‐enhanced magnetic resonance imaging (LGE MRI) was obtained 4.9 ± 0.9 months after infarction, with three‐dimensional (3D) gadolinium enhancement signal intensity maps at 1‐mm and 5‐mm depths from the endocardium. Ultra‐high resolution electroanatomical maps were created using a novel mapping system (Rhythmia Mapping System, Rhythmia Medical/Boston Scientific, Marlborough, MA, USA) Rhythmia Medical, Boston Scientific, Marlborough, MA, USA with an 8.5F catheter with mini‐basket electrode array (64 tiny electrodes, 2.5‐mm spacing, center‐to‐center). Results The maps contained 7,754 ± 1,960 electrograms per animal with a mean resolution of 2.8 ± 0.6 mm. Low bipolar voltage (<2 mV) correlated closely with scar on the LGE MRI and the 3D signal intensity map (1‐mm depth). The scar areas between the MRI signal intensity map and electroanatomic map matched at 87.7% of sites. Bipolar and unipolar voltages, compared in 592 electrograms from four MRI‐defined scar types (endocardial scar, epicardial scar, mottled transmural scar, and dense transmural scar) as well as normal tissue, were significantly different. A unipolar voltage of <13 mV correlated with transmural extension of scar in MRI. Electrograms exhibiting isolated late potentials (ILPs) were manually annotated and ILP maps were created showing ILP location and timing. ILPs were identified in 203 ± 159 electrograms per dog (within low‐voltage areas) and ILP maps showed gradation in timing of ILPs at different locations in the scar. Conclusions Ultra

  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.

  18. Rhesus monkey brain development during late infancy and the effect of phencyclidine: a longitudinal MRI and DTI study.

    PubMed

    Liu, Cirong; Tian, Xiaoguang; Liu, Huilang; Mo, Yin; Bai, Fan; Zhao, Xudong; Ma, Yuanye; Wang, Jianhong

    2015-02-15

    Early brain development is a complex and rapid process, the disturbance of which may cause the onset of brain disorders. Based on longitudinal imaging data acquired from 6 to 16 months postnatal, we describe a systematic trajectory of monkey brain development during late infancy, and demonstrate the influence of phencyclidine (PCP) on this trajectory. Although the general developmental trajectory of the monkey brain was close to that of the human brain, the development in monkeys was faster and regionally specific. Gray matter volume began to decrease during late infancy in monkeys, much earlier than in humans in whom it occurs in adolescence. Additionally, the decrease of gray matter volume in higher-order association regions (the frontal, parietal and temporal lobes) occurred later than in regions for primary functions (the occipital lobe and cerebellum). White matter volume displayed an increasing trend in most brain regions, but not in the occipital lobe, which had a stable volume. In addition, based on diffusion tensor imaging, we found an increase in fractional anisotropy and a decrease in diffusivity, which may be associated with myelination and axonal changes in white matter tracts. Meanwhile, we tested the influence of 14-day PCP treatment on the developmental trajectories. Such treatment tended to accelerated brain maturation during late infancy, although not statistically significant. These findings provide comparative information for the understanding of primate brain maturation and neurodevelopmental disorders.

  19. Free Triiodothyronine Level Correlates with Myocardial Injury and Prognosis in Idiopathic Dilated Cardiomyopathy: Evidence from Cardiac MRI and SPECT/PET Imaging

    PubMed Central

    Wang, Wenyao; Guan, Haixia; Fang, Wei; Zhang, Kuo; Gerdes, A. Martin; Iervasi, Giorgio; Tang, Yi-Da

    2016-01-01

    Thyroid dysfunction is associated with poor prognosis in heart failure, but theories of mechanisms are mainly based on animal experiments, not on human level. We aimed to explore the relation between thyroid function and myocardial injuries in idiopathic dilated cardiomyopathy (IDCM) using cardiac magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and positron emission tomography (PET). Myocardial fibrosis was detected by late gadolinium enhancement (LGE) MRI, and myocardial perfusion/metabolism was evaluated by 99mTc-MIBI SPECT /18F-FDG PET imaging. Across the quartiles of FT3, decreased percentage of segments with LGE and perfusion/metabolism abnormalities were found. As for FT4 and TSH levels, no significant distribution trend of myocardial injuries could be detected. In logistic analysis, FT3 was independently associated with the presence of LGE (OR: 0.140, 95% CI: 0.035–0.567), perfusion abnormalities (OR: 0.172, 95% CI: 0.040–0.738) and metabolism abnormalities (OR: 0.281, 95% CI: 0.081–0.971). After a median follow-up of 46 months, LGE-positive and FT3 < 2.77 pg/mL was identified as the strongest predictor of cardiac events (HR: 8.623, 95% CI: 3.626–16.438). Low FT3 level is associated with myocardial fibrosis and perfusion/metabolism abnormalities in patients with IDCM. The combination of FT3 level and LGE provides useful information for assessing the prognosis of IDCM. PMID:28004791

  20. Molecular MRI of Acute Necrosis with a Novel DNA-Binding Gadolinium Chelate: Kinetics of Cell Death and Clearance in Infarcted Myocardium

    PubMed Central

    Huang, Shuning; Chen, Howard H.; Yuan, Hushan; Dai, Guangping; Schuhle, Daniel T.; Mekkaoui, Choukri; Ngoy, Soeun; Liao, Ronglih; Caravan, Peter; Josephson, Lee; Sosnovik, David E.

    2012-01-01

    Background Current techniques to image cell death in the myocardium are largely non-specific. Here we report the use of a novel DNA-binding gadolinium chelate (Gd-TO) to specifically detect the exposed DNA in acutely necrotic (ruptured) cells in vivo. Methods and Results In vivo MRI was performed in 20 mice with myocardial infarction (MI). The mice were injected with Gd-TO or Gd-DTPA at varying time points post-MI. MRI was performed 2 hours after probe injection, to avoid nonspecific signal from the late gadolinium enhancement effect. Cell rupture (Gd-TO uptake) was present within 2 hours of infarction, but peaked 9–18 hours after the onset of injury. A significant increase in the longitudinal relaxation rate (R1) in the infarct was seen in mice injected with Gd-TO within 48 hours of MI, but not in those injected more than 72 hours post MI (R1 = 1.24 ± 0.08 and 0.92 ± 0.03 s−1, respectively, p < 0.001). Gd-DTPA, unlike Gd-TO, washed completely out of acute infarcts within 2 hours of injection (p < 0.001). The binding of Gd-TO to exposed DNA in acute infarcts was confirmed with fluorescence microscopy. Conclusions Gd-TO specifically binds to acutely necrotic cells and can be used to image the mechanism and chronicity of cell death in injured myocardium. Cell rupture in acute MI begins early but peaks many hours after the onset of injury. The ruptured cells are efficiently cleared by the immune system and are no longer present in the myocardium 72 hours after injury. PMID:21836081

  1. Infarct density distribution by MRI in the porcine model of acute and chronic myocardial infarction as a potential method transferable to the clinic.

    PubMed

    Varga-Szemes, Akos; Simor, Tamas; Lenkey, Zsofia; van der Geest, Rob J; Kirschner, Robert; Toth, Levente; Brott, Brigitta C; Elgavish, Ada; Elgavish, Gabriel A

    2014-06-01

    To study the feasibility of a myocardial infarct (MI) quantification method [signal intensity-based percent infarct mapping (SI-PIM)] that is able to evaluate not only the size, but also the density distribution of the MI. In 14 male swine, MI was generated by 90 min of closed-chest balloon occlusion followed by reperfusion. Seven (n = 7) or 56 (n = 7) days after reperfusion, Gd-DTPA-bolus and continuous-infusion enhanced late gadolinium enhancement (LGE) MRI, and R1-mapping were carried out and post mortem triphenyl-tetrazolium-chloride (TTC) staining was performed. MI was quantified using binary [2 or 5 standard deviation (SD)], SI-PIM and R1-PIM methods. Infarct fraction (IF), and infarct-involved voxel fraction (IIVF) were determined by each MRI method. Bias of each method was compared to the TTC technique. The accuracy of MI quantification did not depend on the method of contrast administration or the age of the MI. IFs obtained by either of the two PIM methods were statistically not different from the IFs derived from the TTC measurements at either MI age. IFs obtained from the binary 2SD method overestimated IF obtained from TTC. IIVF among the three different PIM methods did not vary, but with the binary methods the IIVF gradually decreased with increasing the threshold limit. The advantage of SI-PIM over the conventional binary method is the ability to represent not only IF but also the density distribution of the MI. Since the SI-PIM methods are based on a single LGE acquisition, the bolus-data-based SI-PIM method can effortlessly be incorporated into the clinical image post-processing procedure.

  2. Heart MRI

    MedlinePlus

    Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

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

    PubMed

    Burton, Harold; McLaren, Donald G

    2006-01-09

    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.

  4. The impact of the relaxivity definition on the quantitative measurement of glycosaminoglycans in cartilage by the MRI dGEMRIC method.

    PubMed

    Zheng, Shaokuan; Xia, Yang

    2010-01-01

    The relaxivities (R-values) of the gadolinium diethylene triamine pentaacetic acid (Gd(DTPA)2-) ions in a series of skim-milk solutions at 0-40% milk concentrations were measured using NMR spectroscopy. The R-value was found to be approximately linearly proportional to the concentration of the solid component in the milk solution. Using the R-value at 20% solid component (approximately the solid concentration in bovine nasal cartilage), the glycosaminoglycan concentration in bovine nasal cartilage can be quantified using the MRI delayed gadolinium-enhanced MRI of cartilage method without the customary scaling factor of 2. This finding is also supported by the measurements using 23Na NMR spectroscopy, 23Na inductively coupled plasma analysis, and biochemical assay. The choice of the R-value definition in the MRI delayed gadolinium-enhanced MRI of cartilage method is discussed, and the definition of Gd(DTPA)2- ions as "millimole per volume of tissue (or milk solution for substitution)" should be used.

  5. Head MRI

    MedlinePlus

    ... the head; MRI - cranial; NMR - cranial; Cranial MRI; Brain MRI; MRI - brain; MRI - head ... the test, tell your provider if you have: Brain aneurysm clips An artificial heart valves Heart defibrillator ...

  6. 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

  7. 18F-FDG PET/CT/MRI Fusion Images Showing Cranial and Peripheral Nerve Involvement in Neurolymphomatosis

    PubMed Central

    Trevisan, Ana Carolina; Ribeiro, Fernanda Borges; Itikawa, Emerson Nobuyuki; Alexandre, Leonardo Santos; Pitella, Felipe Arriva; Santos, Antonio Carlos; Simões, Belinda Pinto; Wichert-Ana, Lauro

    2017-01-01

    We report a 56-year-old female patient with non-Hodgkin's diffuse large B cell lymphoma (NHL) who, on magnetic resonance imaging (MRI) with a T1 weighted and gadolinium-enhanced imaging, was found to have thickening and infiltration in 75% of peripheral nerves of the patient and enlargements of cranial nerves, possibly related to lymphomatous infiltration. Subsequent positron emission tomography/computed tomography (PET/CT) using 18F-labeled 2-deoxy-2-fluoro-d-glucose (18F-FDG) showed widespread active involvement of the cervical plexus, bilateral peripheral nerves, right femoral nerve, the parasellar region of the skull, and marked hypermetabolism in the left trigeminal ganglia. This case re-emphasizes that while CT and MRI provide anatomical details, 18F-FDG PET/CT images better delineate the metabolic activity of neurolymphomatosis (NL) in the peripheral and central nervous system. PMID:28242998

  8. 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.

  9. Comparison of CT and MRI brain tumor imaging using a canine glioma model.

    PubMed

    Whelan, H T; Clanton, J A; Wilson, R E; Tulipan, N B

    1988-01-01

    A canine gliosarcoma model was used to study the effectiveness of magnetic resonance imaging (MRI) with gadolinium contrast enhancement in defining the histologic margins of brain tumors. The effectiveness of this technique was compared to conventional computed tomography (CT) using iodinated contrast enhancement. Cultured canine gliosarcoma cells were injected into the left hemisphere of adult mongrel dogs. The dogs developed brain tumors and progressive clinical signs. Serial MRI with and without gadolinium diethylene triamine penta-acetic acid was compared to serial CT with and without sodium iothalamate obtained on the same days. After the final scans, animals were sacrificed; the brains were removed and processed for routine histopathologic study. All tumors were visualized with contrast-enhanced MRI which proved most sensitive. Gadolinium di-ethylene triamine penta-acetic acid caused bright enhancement of tumors in a distribution that consistently corresponded to areas of pathologically proved tumor infiltration. Gross and microscopic autopsy findings correlated better with MRI than with CT which tended to produce poorer resolution and underrepresent the size of viable tumor. Gadolinium-enhanced MRI is more accurate than unenhanced MRI, unenhanced CT, or enhanced CT in defining the histologic margins of tumors.

  10. Single-trial EEG-informed fMRI reveals spatial dependency of BOLD signal on early and late IC-ERP amplitudes during face recognition.

    PubMed

    Wirsich, Jonathan; Bénar, Christian; Ranjeva, Jean-Philippe; Descoins, Médéric; Soulier, Elisabeth; Le Troter, Arnaud; Confort-Gouny, Sylviane; Liégeois-Chauvel, Catherine; Guye, Maxime

    2014-10-15

    Simultaneous EEG-fMRI has opened up new avenues for improving the spatio-temporal resolution of functional brain studies. However, this method usually suffers from poor EEG quality, especially for evoked potentials (ERPs), due to specific artifacts. As such, the use of EEG-informed fMRI analysis in the context of cognitive studies has particularly focused on optimizing narrow ERP time windows of interest, which ignores the rich diverse temporal information of the EEG signal. Here, we propose to use simultaneous EEG-fMRI to investigate the neural cascade occurring during face recognition in 14 healthy volunteers by using the successive ERP peaks recorded during the cognitive part of this process. N170, N400 and P600 peaks, commonly associated with face recognition, were successfully and reproducibly identified for each trial and each subject by using a group independent component analysis (ICA). For the first time we use this group ICA to extract several independent components (IC) corresponding to the sequence of activation and used single-trial peaks as modulation parameters in a general linear model (GLM) of fMRI data. We obtained an occipital-temporal-frontal stream of BOLD signal modulation, in accordance with the three successive IC-ERPs providing an unprecedented spatio-temporal characterization of the whole cognitive process as defined by BOLD signal modulation. By using this approach, the pattern of EEG-informed BOLD modulation provided improved characterization of the network involved than the fMRI-only analysis or the source reconstruction of the three ERPs; the latter techniques showing only two regions in common localized in the occipital lobe.

  11. Response to immunotherapy in CLIPPERS: clinical, MRI, and MRS follow-up.

    PubMed

    Sempere, Angel P; Mola, Santiago; Martin-Medina, Patricia; Bernabeu, Angela; Khabbaz, Elias; Lopez-Celada, Susana

    2013-04-01

    Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a recently defined inflammatory central nervous system disorder responsive to steroids with characteristic magnetic resonance imaging (MRI) features. We report a 69-year-old man presenting with gait ataxia with the characteristic MRI features of CLIPPERS and describe the clinical, MRI, and magnetic resonance spectroscopy (MRS) follow-up after treatment with glucocorticosteroids. Brain and spine MRI showed punctate enhancement peppering the brainstem, cerebellar peduncles, and upper cervical cord. In MRS, the ratio of N-acetyl aspartate to creatine (NAA/Cr) was significantly decreased in the pons and both thalami. An extensive evaluation found no alternative diagnoses. Treatment with steroids led to rapid clinical improvement. Repeat MRI and MRS showed complete resolution of gadolinium-enhancing lesions and recovery of NAA/Cr levels in the pons and thalami. After 1 month of tapering oral steroids, weekly oral methotrexate was started and the patient has remained stable for the past 6 months.

  12. MRI and low back pain

    MedlinePlus

    Backache - MRI; Low back pain - MRI; Lumbar pain - MRI; Back strain - MRI; Lumbar radiculopathy - MRI; Herniated intervertebral disk - MRI; Prolapsed intervertebral disk - MRI; Slipped disk - MRI; Ruptured ...

  13. 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.

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

    PubMed

    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.

  15. Superior MRI outcomes with alemtuzumab compared with subcutaneous interferon β-1a in MS

    PubMed Central

    Fisher, Elizabeth; Brinar, Vesna V.; Cohen, Jeffrey A.; Coles, Alasdair J.; Giovannoni, Gavin; Hartung, Hans-Peter; Havrdova, Eva; Selmaj, Krzysztof W.; Stojanovic, Miroslav; Weiner, Howard L.; Lake, Stephen L.; Margolin, David H.; Thomas, David R.; Panzara, Michael A.; Compston, D. Alastair S.

    2016-01-01

    Objective: To describe detailed MRI results from 2 head-to-head phase III trials, Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis Study I (CARE-MS I; NCT00530348) and Study II (CARE-MS II; NCT00548405), of alemtuzumab vs subcutaneous interferon β-1a (SC IFN-β-1a) in patients with active relapsing-remitting multiple sclerosis (RRMS). Methods: The impact of alemtuzumab 12 mg vs SC IFN-β-1a 44 μg on MRI measures was evaluated in patients with RRMS who were treatment-naive (CARE-MS I) or who had an inadequate response, defined as at least one relapse, to prior therapy (CARE-MS II). Results: Both treatments prevented T2-hyperintense lesion volume increases from baseline. Alemtuzumab was more effective than SC IFN-β-1a on most lesion-based endpoints in both studies (p < 0.05), including decreased risk of new/enlarging T2 lesions over 2 years and gadolinium-enhancing lesions at year 2. Reduced risk of new T1 lesions (p < 0.0001) and gadolinium-enhancing lesion conversion to T1-hypointense black holes (p = 0.0078) were observed with alemtuzumab vs SC IFN-β-1a in CARE-MS II. Alemtuzumab slowed brain volume loss over 2 years in CARE-MS I (p < 0.0001) and II (p = 0.012) vs SC IFN-β-1a. Conclusions: Alemtuzumab demonstrated greater efficacy than SC IFN-β-1a on MRI endpoints in active RRMS. The superiority of alemtuzumab was more prominent during the second year of both studies. These findings complement the superior clinical efficacy of alemtuzumab over SC IFN-β-1a in RRMS. ClinicalTrials.gov identifier: NCT00530348 and NCT00548405. Classification of evidence: The results reported here provide Class I evidence that, for patients with active RRMS, alemtuzumab is superior to SC IFN-β-1a on multiple MRI endpoints. PMID:27590291

  16. 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.

  17. 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.

  18. Three cases of CLIPPERS: a serial clinical, laboratory and MRI follow-up study.

    PubMed

    Kastrup, O; van de Nes, J; Gasser, T; Keyvani, K

    2011-12-01

    The aim of the study was to further determine the pathophysiology, clinical course, MRI-features and response to therapy of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS), which has recently been proposed as a rare chronic inflammatory central nervous system disorder responsive to immunosuppressive therapy. Three patients with this rare entity underwent serial clinical and bimonthly MRI follow-up over a period of up to 16 months. Extensive laboratory work-up and brain biopsy were performed. Intravenous methylprednisolone or oral dexamethasone was administered as treatment, additionally cyclophosphamide in one patient. Clinically, diplopia, nystagmus, ataxia and facial paresthesia were the cardinal symptoms. Magnetic resonance imaging (MRI) disclosed patchy spot-like gadolinium enhancement in a "salt-and-pepper like appearance" in the pons, midbrain and cerebellum, in two cases with thalamic and in the other with spinal involvement. Brain biopsies demonstrated a predominantly angiocentric but also diffuse infiltration pattern by small mature lymphocytes. Treatment with steroids led to rapid clinical improvement and marked resolution of MRI lesions. As discontinuation of steroids led to clinical relapse, one patient was treated with a further course of steroids and the other with steroids and cyclophosphamide as immunosuppressive therapy. This led to stable remission with only mild clinical residue and normalization of MRI. Extensive laboratory and radiological work-up could not identify any other cause of the disease. Of note, in two cases a marked elevation of IgE in serum was found initially and throughout the course. CLIPPERS seems to be a distinct inflammatory central nervous system disorder. It shows characteristic MRI core features. Extrapontine involvement seems to be frequent. Histologically it is characterised by predominantly angiocentric infiltration by small mature lymphocytes. A pathogenetic

  19. Shoulder MRI

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  20. Knee MRI

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  1. Shoulder MRI

    MedlinePlus

    ... of the shoulder uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  2. Knee MRI

    MedlinePlus

    ... of the knee uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  3. Diffuse Infantile Hepatic Hemangioendothelioma With Early Central Enhancement in an Adult: A Case Report of CT and MRI Findings.

    PubMed

    Dong, Aisheng; Dong, Hui; Zuo, Changjing; He, Tianlin

    2015-12-01

    Infantile hepatic hemangioendothelioma (IHH) is the most common vascular tumor of the liver in infancy. Adult with IHH is extremely rare. We presented a diffuse IHH in an adult patient with computed tomography (CT) and magnetic resonance image (MRI) findings.A 39-year-old man was admitted to our hospital because of a 2-year history of abnormal liver function tests and a 7-day history of jaundice. Physical examination revealed enlarged liver. Unenhanced abdominal CT showed enlargement of the liver with diffuse hypodensity. Enhanced CT on the arterial phase revealed multiple centrally enhanced lesions diffusely involved the enlarged liver. The enhanced areas of the lesions became larger on the portal phase and all the lesions became homogeneous enhanced on the delayed phase. These lesions showed heterogeneously hyperintense on T2-weighted image, hypointense on T1-weighted image, and early centrally enhanced on dynamic gadolinium-enhanced MRI, with complete tumor enhancement after 180 s. The patient underwent orthotopic liver transplantation. IHH type 2 was confirmed by pathology. The patient died of tumor recurrence in the liver 4 months after transplantation.Unlike the previously described imaging appearances of IHH, this case showed diffuse nodules with early central enhancement on CT and MRI. Considering the importance of the ability to differentiate IHH from other hepatic tumors, radiologists should be aware of these imaging appearances to establish knowledge of the entire spectrum of IHH.

  4. MRI renaissance.

    PubMed

    Hensley, S

    1997-12-01

    A few years ago, magnetic resonance imaging was healthcare's version of a foreign sports car-flashy, expensive and impractical. Now, after years in the doldrums, sales of MRI systems are roaring back. An aging fleet of MRI scanners due for replacement and a hearty increase in doctors' use of the versatile imaging tools are combining to fuel the surge in demand, vendors and customers say.

  5. Categorization of Pathology Causing Low Back Pain using Magnetic Resonance Imaging (MRI)

    PubMed Central

    Nadhamuni, Kulasekaran; Karthikeyan, T.

    2015-01-01

    Background: Low backache is the most common ailment flooding the orthopaedic clinic. Most of the population at least once seek medical attention for low back ache. Magnetic Resonance Imaging (MRI) is a non invasive, commonly used diagnosing modality and accurate in diagnosing pathology causing low back ache. Aim: To classify and quantify the causes of low back pain referred to radiology department by MRI. Materials and Methods: Patients with back pain referred to radiology department were subjected to single MRI scan after ruling out any contraindications using the following sequences: T1W Turbo Spin Echo, T2W Turbo Spin Echo, Gradient-echo, Myelogram and short TI inversion recovery (STIR), in all imaging planes. Gadolinium enhanced T1W turbo spin echo sequence was used wherever necessary. Results: Data were analysed using Excel 2007, SPSS 14, Students t-test. Degenerative disc diseases were the commonest pathology followed by congenital and traumatic lesions. Neoplastic lesions were the least common. Commonest herniation type being the disc bulge (79%) followed by disc protrusion (15%), disc extrusion (6%) and disc sequestration (<1%). The posterolateral disc herniation as the commonest and foraminal the least. Sacralisation was the most common congenital spinal anomaly, followed by lumbar scoliosis and perineural cyst. There is no sex difference in disc protrusion but male preponderance in disc extrusion with subligmentous extrusion. Conclusion: MRI is useful in classifying the spinal lesions which again influences the treatment modality and clinical outcome. Degenerative disc disease is the single most common category which accounts for most the Low Back Ache for which a preventing strategy should be drafted. PMID:25738056

  6. 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.

  7. MRI (Magnetic Resonance Imaging)

    MedlinePlus

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  8. MRI Safety during Pregnancy

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z MRI Safety During Pregnancy Magnetic resonance imaging (MRI) Illness ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor ...

  9. Battlefield MRI

    DOE PAGES

    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.

  10. Sodium MRI.

    PubMed

    Ouwerkerk, Ronald

    2011-01-01

    Sodium ((23)Na) imaging has a place somewhere between (1)H-MRI and MR spectroscopy (MRS). Like MRS it potentially provides information on metabolic processes, but only one single resonance of ionic (23)Na is observed. Therefore pulse sequences do not need to code for a chemical shift dimension, allowing (23)Na images to be obtained at high resolutions as compared to MRS. In this chapter the biological significance of sodium in the brain will be discussed, as well as methods for observing it with (23)Na-MRI. Many vital cellular processes and interactions in excitable tissues depend on the maintenance of a low intracellular and high extracellular sodium concentration. Healthy cells maintain this concentration gradient at the cost of energy. Leaky cell membranes or an impaired energy metabolism immediately leads to an increase in cytosolic total tissue sodium. This makes sodium a biomarker for ischemia, cancer, excessive tissue activation, or tissue damage as might be caused by ablation therapy. Special techniques allow quantification of tissue sodium for the monitoring of disease or therapy in longitudinal studies or preferential observation of the intracellular component of the tissue sodium. New methods and high-field magnet technology provide new opportunities for (23)Na-MRI in clinical and biomedical research.

  11. 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.

  12. 4D flow imaging with MRI

    PubMed Central

    Stankovic, Zoran; Allen, Bradley D.; Garcia, Julio; Jarvis, Kelly B.

    2014-01-01

    Magnetic resonance imaging (MRI) has become an important tool for the clinical evaluation of patients with cardiovascular disease. Since its introduction in the late 1980s, 2-dimensional phase contrast MRI (2D PC-MRI) has become a routine part of standard-of-care cardiac MRI for the assessment of regional blood flow in the heart and great vessels. More recently, time-resolved PC-MRI with velocity encoding along all three flow directions and three-dimensional (3D) anatomic coverage (also termed ‘4D flow MRI’) has been developed and applied for the evaluation of cardiovascular hemodynamics in multiple regions of the human body. 4D flow MRI allows for the comprehensive evaluation of complex blood flow patterns by 3D blood flow visualization and flexible retrospective quantification of flow parameters. Recent technical developments, including the utilization of advanced parallel imaging techniques such as k-t GRAPPA, have resulted in reasonable overall scan times, e.g., 8-12 minutes for 4D flow MRI of the aorta and 10-20 minutes for whole heart coverage. As a result, the application of 4D flow MRI in a clinical setting has become more feasible, as documented by an increased number of recent reports on the utility of the technique for the assessment of cardiac and vascular hemodynamics in patient studies. A number of studies have demonstrated the potential of 4D flow MRI to provide an improved assessment of hemodynamics which might aid in the diagnosis and therapeutic management of cardiovascular diseases. The purpose of this review is to describe the methods used for 4D flow MRI acquisition, post-processing and data analysis. In addition, the article provides an overview of the clinical applications of 4D flow MRI and includes a review of applications in the heart, thoracic aorta and hepatic system. PMID:24834414

  13. The Role of Cardiac MRI in the Diagnosis and Risk Stratification of Hypertrophic Cardiomyopathy

    PubMed Central

    Maron, Martin S

    2016-01-01

    Hypertrophic cardiomyopathy (HCM), the most common genetic cardiomyopathy, is a disease characterised by substantial heterogeneity. Although the majority of patients with HCM remain asymptomatic with near-normal longevity, a small, but important, subset remain at risk for a wide range of clinical outcomes including sudden death. Cardiovascular magnetic resonance (CMR), with its high spatial resolution and tomographic imaging capability, has emerged as an imaging modality particularly well suited to characterise the phenotypic expression of HCM. CMR helps in the diagnosis of HCM by identifying areas of hypertrophy not well visualised by echocardiography, providing more accurate wall thickness measurements and differentiating HCM from other causes of left ventricular (LV) hypertrophy. CMR has led to the identification of novel subgroups of patients with HCM, including those with LV apical aneurysms (a subgroup at increased risk for ventricular arrhythmias and thromboembolic stroke), as well as abnormalities that contribute to LV outflow obstruction. Additionally, contrast-enhanced CMR with late-gadolinium enhancement (LGE) has recognised patients with extensive LGE (≥15 % LV myocardium) as individuals who may be at increased risk of sudden death, independent of other high-risk features, with implications on management strategies including consideration for primary prevention implantable cardioverter defibrillator therapy. These observations justify an expanded role of CMR in the routine clinical assessment of patients with HCM. PMID:28116085

  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. 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.

  16. Intracranial hypotension: the nonspecific nature of MRI findings.

    PubMed

    Bruera, O C; Bonamico, L; Giglio, J A; Sinay, V; Leston, J A; Figuerola, M L

    2000-01-01

    We present three patients who complained of postural headache related to different types of intracranial hypotension: spontaneous or primary, and secondary, but presenting the same findings on brain magnetic resonance imaging. Diffuse pachymeningeal gadolinium enhancement supports the belief that the enhancement is a nonspecific meningeal reaction to low pressure.

  17. Low incidence of left atrial delayed enhancement with MRI in patients with AF: a single-centre experience

    PubMed Central

    Bois, John P; Glockner, James; Young, Phillip M; Foley, Thomas A; Sheldon, Seth; Newman, Darrell B; Lin, Grace; Packer, Douglas L; Brady, Peter A

    2017-01-01

    Background Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. One potential target for ablation is left atrial (LA) scar (LAS) regions that may be the substrate for re-entry within the atria, thereby sustaining AF. Identification of LAS through LA delayed gadolinium enhancement (LADE) with MRI has been proposed. Objectives We sought to evaluate LADE in patients referred for catheter ablation of AF. Methods Prospective analysis was conducted of consecutive patients who underwent pulmonary vein antrum isolation (PVAI) ablation for AF at a single institution. Patients underwent LADE with MRI to determine LAS regions before ablation. MRI data were analysed independently in accordance with prespecified institutional protocol by two staff cardiac radiologists to whom patient outcomes were masked, and reports of LADE were documented. Where no initial consensus occurred regarding delayed enhancement (DE), a third staff cardiac radiologist independently reviewed the case and had the deciding vote. Results Of the 149 consecutive patients (mean (SD) age, 59 (9) years), AF was persistent in 64 (43%) and paroxysmal in 85 (57%); 45 (30%) had prior ablation. Only five patients (3%) had identifiable DE in LA walls (persistent AF, n=1; paroxysmal AF, n=4). LADE was present in two (4%) of the 45 patients with previous left PVAI. The presence of LADE was not associated with a higher recurrence rate of AF. Conclusions In contrast to previous studies, the finding of DE within LA walls was uncommon and, when present, did not correlate with AF type or risk of AF recurrence. It therefore is of unclear clinical significance. PMID:28123766

  18. Altered spontaneous brain activity pattern in patients with late monocular blindness in middle-age using amplitude of low-frequency fluctuation: a resting-state functional MRI study

    PubMed Central

    Li, Qing; Huang, Xin; Ye, Lei; Wei, Rong; Zhang, Ying; Zhong, Yu-Lin; Jiang, Nan; Shao, Yi

    2016-01-01

    Objective Previous reports have demonstrated significant brain activity changes in bilateral blindness, whereas brain activity changes in late monocular blindness (MB) at rest are not well studied. Our study aimed to investigate spontaneous brain activity in patients with late middle-aged MB using the amplitude of low-frequency fluctuation (ALFF) method and their relationship with clinical features. Methods A total of 32 patients with MB (25 males and 7 females) and 32 healthy control (HC) subjects (25 males and 7 females), similar in age, sex, and education, were recruited for the study. All subjects were performed with resting-state functional magnetic resonance imaging scanning. The ALFF method was applied to evaluate spontaneous brain activity. The relationships between the ALFF signal values in different brain regions and clinical features in MB patients were investigated using correlation analysis. Results Compared with HCs, the MB patients had marked lower ALFF values in the left cerebellum anterior lobe, right parahippocampal gyrus, right cuneus, left precentral gyrus, and left paracentral lobule, but higher ALFF values in the right middle frontal gyrus, left middle frontal gyrus, and left supramarginal gyrus. However, there was no linear correlation between the mean ALFF signal values in brain regions and clinical manifestations in MB patients. Conclusion There were abnormal spontaneous activities in many brain regions including vision and vision-related regions, which might indicate the neuropathologic mechanisms of vision loss in the MB patients. Meanwhile, these brain activity changes might be used as a useful clinical indicator for MB. PMID:27980398

  19. Late results.

    PubMed

    Daly, B D

    1999-08-01

    Pneumonectomy is performed for a number of benign and malignant conditions. It is most commonly performed for lung cancer. Adjuvant and neoadjuvant protocols have increased the number of these operations being performed and the long-term results are improving. Pneumonectomy may also be performed for metastases to lung and for mesothelioma with encouraging results. Some bronchial adenomas require pneumonectomy. Treatment of resistant mycobacteria or the complications of tuberculosis frequently require pneumonectomy. Late bronchopleural fistulae, esophagopleural fistulae, and empyema may occur.

  20. Sinus MRI scan

    MedlinePlus

    ... sinuses. The test is noninvasive. MRI uses powerful magnets and radio waves instead of radiation. Signals from ... in the eyes. Because the MRI contains a magnet, metal-containing objects such as pens, pocketknives, and ...

  1. 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 ...

  2. MRI Safety during Pregnancy

    MedlinePlus

    ... 20 to 40 minutes. top of page Contrast material For some MRI exams, a contrast material called gadolinium will need to be injected into a vein in the arm. While contrast material sometimes improves the MRI images, during pregnancy the ...

  3. A retrospective study: cardiac MRI of fulminant myocarditis in children—can we evaluate the short-term outcomes?

    PubMed Central

    Wang, Haipeng; Zhao, Bin; Jia, Haipeng; Gao, Fei; Zhao, Junyu

    2016-01-01

    Background Fulminant myocarditis (FM) is an inflammatory disease of the myocardium that results in ventricular systolic dysfunction and causes acute-onset heart failure. Cardiac magnetic resonance (CMR) has become the primary noninvasive tool for the diagnosis and evaluation of myocarditis. The aim of our study was to assess the CMR findings at different course of FM and the short-term outcomes of fulminant myocarditis (FM) in children. Methods Eight FM children with CMR examinations were included in our study. Initial baseline CMR was performed 10 days (range, 7–20 days) after onset of FM and follow-up CMR after 55 days (range, 33–75 days). Cardiac morphology and function and myocardial tissue characterization at baseline and follow-up CMR were compared using paired T-test and Mann–Whitney U test. The clinical data and initial CMR findings were also compared to predict short-term outcomes. Results The median age of eight FM children was 8.5 years old (range, 3–14). The initial CMR findings were most common with early gadolinium enhancement (EGE, 100%), followed by signal increasing on T2WI and late gadolinium enhancement (LGE, 87.5%), increased septal thickness (75.0%) and increased left ventricle ejection fraction (LVEF, 50.0%). Only three LGE (37.5%), one signal increasing on T2WI (12.5%) and one increased LVEF (12.5%) were found at follow-up. Statistically significant differences were found between initial and follow-up CMR abnormalities in the septal thickness, left ventricular end-diastolic diameter (LVEDD), end-systolic volume (ESV), LVEF, left ventricular mass, T2 ratio and LGE area (P = 0.011, P = 0.042, P = 0.016, P = 0.001, P = 0.003, P = 0.011, P = 0.020). The children with full recovery performed higher incidence of III° atrioventricular block (AVB, five cases VS 0 case) and smaller LGE area (104.0 ± 14.5 mm2 VS 138.0 ± 25.2 mm2) at baseline CMR. Discussion The CMR findings of FM in children were characteristic and

  4. 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

  5. A Rare Right Ventricular Involvement of Eosinophilic Granulomatosis Demonstrated by Cardiac MRI

    PubMed Central

    Francis, Willington; Aziz Eid Al Kuwari, Maryam A.; Ghareep, Abdel-Naser; Peyrou, Jérôme; Szmigielski, Wojciech

    2016-01-01

    Summary Background Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis with a prevalence rate of seven per million. Cardiac involvement was reported in 20–50%, yet with improved diagnostic methods, the frequency of cardiac involvement is expected to be even higher. It can result in significant morbidity and mortality, accounting for about 50% of death. Cardiac magnetic resonance (CMR) imaging is used to evaluate the myocardium, valves, coronary arteries, pericardium, also to assess cardiac structure and function. Perfusion study allows tissue characterisation with a suggestive pattern of late gadolinium enhancement. Case Report We report a rare case of EGPA in a 54-year-old male patient who presented with fever, sore throat and dizziness. Echocardiography showed a filling defect at the apex of the right ventricle (RV). CMR findings suggested the diagnosis of EGPA by demonstrating an impressive lesion at RV apex with the typical 3-layer appearance and thrombus formation. Post-gadolinium subendocardial hyperenhancement suggested focal involvement at the inferolateral wall of the left ventricle. Computed Tomography (CT) was done to rule out calcific or soft plaques of the coronary arteries, small vessel vasculitis and small aneurysm. CT scan showed a low-attenuation lesion at the inner wall of the right ventricle. In the lungs, bilateral interstitial changes and bilateral cystic bronchiectases were found. Under appropriate treatment, the patient improved clinically. Conclusions It is of crucial importance to perform full cardiac imaging that includes CMR even in asymptomatic patients with suspected EGPA, since early identification of cardiac involvement may allow to apply appropriate therapy and full recovery of the patient. PMID:28058073

  6. 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

  7. 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.

  8. Reliability of Early Magnetic Resonance Imaging (MRI) and Necessity of Repeating MRI in Noncooled and Cooled Infants With Neonatal Encephalopathy.

    PubMed

    Chakkarapani, Elavazhagan; Poskitt, Kenneth J; Miller, Steven P; Zwicker, Jill G; Xu, Qi; Wong, Darren S T; Roland, Elke H; Hill, Alan; Chau, Vann

    2016-04-01

    In cooled newborns with encephalopathy, although late magnetic resonance imaging (MRI) scan (10-14 days of age) is reliable in predicting long-term outcome, it is unknown whether early scan (3-6 days of life) is. We compared the predominant pattern and extent of lesion between early and late MRI in 89 term neonates with neonatal encephalopathy. Forty-three neonates (48%) were cooled. The predominant pattern of lesions and the extent of lesion in the watershed region agreed near perfectly in noncooled (kappa = 0.94; k = 0.88) and cooled (k = 0.89; k = 0.87) infants respectively. There was perfect agreement in the extent of lesion in the basal nuclei in noncooled infants (k = 0.83) and excellent agreement in cooled infants (k = 0.67). Changes in extent of lesions on late MRI occurred in 19 of 89 infants, with higher risk in infants with hypoglycemia and moderate-severe lesions in basal nuclei. In most term neonates with neonatal encephalopathy, early MRI (relative to late scan) robustly predicts the predominant pattern and extent of injury.

  9. 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 ...

  10. MRI of the Breast

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  11. MRI of the Prostate

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  12. MRI of the Chest

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  13. Magnetic Resonance Imaging (MRI)

    MedlinePlus

    ... problems (in men)Path to improved healthIf your primary care doctor determines that you should have an MRI, ... may not apply to everyone. Talk to your family doctor to find out if this information applies to ...

  14. MRI of the Breast

    MedlinePlus

    ... of the breast uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. Manganese enhanced MRI (MEMRI): neurophysiological applications

    PubMed Central

    Inoue, Taeko; Majid, Tabassum; Pautler, Robia G.

    2012-01-01

    Manganese ion (Mn2+) is a calcium (Ca2+) analog that can enter neurons and other excitable cells through voltage gated Ca2+ channels. Mn2+ is also a paramagnetic that shortens the spin-lattice relaxation time constant (T1) of tissues where it has accumulated, resulting in positive contrast enhancement. Mn2+ was first investigated as a magnetic resonance imaging (MRI) contrast agent approximately 20 years ago to assess the toxicity of the metal in rats. In the late 1990s, Alan Koretsky and colleagues pioneered the use of manganese enhanced MRI (MEMRI) towards studying brain activity, tract tracing and enhancing anatomical detail. This review will describe the methodologies and applications of MEMRI in the following areas: monitoring brain activity in animal models, in vivo neuronal tract tracing and using MEMRI to assess in vivo axonal transport rates. PMID:22098448

  19. Molecular fMRI

    PubMed Central

    Bartelle, Benjamin B.; Barandov, Ali

    2016-01-01

    Comprehensive analysis of brain function depends on understanding the dynamics of diverse neural signaling processes over large tissue volumes in intact animals and humans. Most existing approaches to measuring brain signaling suffer from limited tissue penetration, poor resolution, or lack of specificity for well-defined neural events. Here we discuss a new brain activity mapping method that overcomes some of these problems by combining MRI with contrast agents sensitive to neural signaling. The goal of this “molecular fMRI” approach is to permit noninvasive whole-brain neuroimaging with specificity and resolution approaching current optical neuroimaging methods. In this article, we describe the context and need for molecular fMRI as well as the state of the technology today. We explain how major types of MRI probes work and how they can be sensitized to neurobiological processes, such as neurotransmitter release, calcium signaling, and gene expression changes. We comment both on past work in the field and on challenges and promising avenues for future development. SIGNIFICANCE STATEMENT Brain researchers currently have a choice between measuring neural activity using cellular-level recording techniques, such as electrophysiology and optical imaging, or whole-brain imaging methods, such as fMRI. Cellular level methods are precise but only address a small portion of mammalian brains; on the other hand, whole-brain neuroimaging techniques provide very little specificity for neural pathways or signaling components of interest. The molecular fMRI techniques we discuss have particular potential to combine the specificity of cellular-level measurements with the noninvasive whole-brain coverage of fMRI. On the other hand, molecular fMRI is only just getting off the ground. This article aims to offer a snapshot of the status and future prospects for development of molecular fMRI techniques. PMID:27076413

  20. MRI-guided brachytherapy

    PubMed Central

    Tanderup, Kari; Viswanathan, Akila; Kirisits, Christian; Frank, Steven J.

    2014-01-01

    The application of MRI-guided brachytherapy has demonstrated significant growth during the last two decades. Clinical improvements in cervix cancer outcomes have been linked to the application of repeated MRI for identification of residual tumor volumes during radiotherapy. This has changed clinical practice in the direction of individualized dose administration, and mounting evidence of improved clinical outcome with regard to local control, overall survival as well as morbidity. MRI-guided prostate HDR and LDR brachytherapy has improved the accuracy of target and organs-at-risk (OAR) delineation, and the potential exists for improved dose prescription and reporting for the prostate gland and organs at risk. Furthermore, MRI-guided prostate brachytherapy has significant potential to identify prostate subvolumes and dominant lesions to allow for dose administration reflecting the differential risk of recurrence. MRI-guided brachytherapy involves advanced imaging, target concepts, and dose planning. The key issue for safe dissemination and implementation of high quality MRI-guided brachytherapy is establishment of qualified multidisciplinary teams and strategies for training and education. PMID:24931089

  1. 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

  2. Predominant Corticospinal Tract Involvement in a Late Infant with Krabbe Disease

    PubMed Central

    Yoshimura, Ayumi; Kibe, Tetsuya; Irahara, Kaori; Sakai, Norio; Yokochi, Kenji

    2016-01-01

    A case of late-infantile Krabbe disease in a patient who presented with developmental regression and spastic quadriplegia in late infancy is reported. Brain magnetic resonance imaging (MRI) at 11 months of age showed predominant corticospinal tract involvement, which usually appears in adult Krabbe disease. Galactocerebrosidase activity in lymphocytes and skin fibroblasts was very low. Genetic testing revealed compound heterozygous mutations of the galactocerebrosidase (GALC) gene, c.635_646 delinsCTC and c.1901T>C [p.L618S], both of which are known pathogenic mutations. It has been reported that the c.1901T>C [p.L618S] mutation is associated with the late-onset phenotype and, in a past case, a homozygous mutation at this location showed predominant corticospinal tract involvement on MRI. Although further analysis is needed to identify the pathophysiological mechanism, this combination of mutations is likely to be associated with this unusual MRI finding in late-infantile Krabbe disease. Because these types of mutations are common for Japanese patients, it is possible that there are more undiagnosed and late-diagnosed patients of late-infantile Krabbe disease who display limited lesions on MRI. Pediatricians should be aware that patients with late-infantile Krabbe disease can present with predominant corticospinal tract involvement on MRI. PMID:27679535

  3. Multidimensional diffusion MRI

    NASA Astrophysics Data System (ADS)

    Topgaard, Daniel

    2017-02-01

    Principles from multidimensional NMR spectroscopy, and in particular solid-state NMR, have recently been transferred to the field of diffusion MRI, offering non-invasive characterization of heterogeneous anisotropic materials, such as the human brain, at an unprecedented level of detail. Here we revisit the basic physics of solid-state NMR and diffusion MRI to pinpoint the origin of the somewhat unexpected analogy between the two fields, and provide an overview of current diffusion MRI acquisition protocols and data analysis methods to quantify the composition of heterogeneous materials in terms of diffusion tensor distributions with size, shape, and orientation dimensions. While the most advanced methods allow estimation of the complete multidimensional distributions, simpler methods focus on various projections onto lower-dimensional spaces as well as determination of means and variances rather than actual distributions. Even the less advanced methods provide simple and intuitive scalar parameters that are directly related to microstructural features that can be observed in optical microscopy images, e.g. average cell eccentricity, variance of cell density, and orientational order - properties that are inextricably entangled in conventional diffusion MRI. Key to disentangling all these microstructural features is MRI signal acquisition combining isotropic and directional dimensions, just as in the field of multidimensional solid-state NMR from which most of the ideas for the new methods are derived.

  4. Usefulness of cardiac MRI in the prognosis and follow-up of ischemic heart disease.

    PubMed

    Hidalgo, A; Pons-Lladó, G

    2015-01-01

    Cardiac magnetic resonance imaging (MRI) is an important tool that makes it possible to evaluate patients with cardiovascular disease; in addition to infarction and alterations in myocardial perfusion, cardiac MRI is useful for evaluating other phenomena such as microvascular obstruction and ischemia. The main prognostic factors in cardiac MRI are ventricular dysfunction, necrosis in late enhancement sequences, and ischemia in stress sequences. In acute myocardial infarction, cardiac MRI can evaluate the peri-infarct zone and quantify the size of the infarct. Furthermore, cardiac MRI's ability to detect and evaluate microvascular obstruction makes it a fundamental tool for establishing the prognosis of ischemic heart disease. In patients with chronic ischemic heart disease, cardiac MRI can detect ischemia induced by pharmacological stress and can diagnose infarcts that can be missed on other techniques.

  5. Radiotherapy Planning using MRI

    PubMed Central

    Schmidt, Maria A; Payne, Geoffrey S

    2016-01-01

    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 minimised, 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. PMID:26509844

  6. Magnetic Resonance Imaging (MRI) (For Teens)

    MedlinePlus

    ... the MRI table. A specially trained technician (or "tech") operates the MRI machine. He or she may ... can't stay still during MRI. Sometimes MRI techs sedate teens who have trouble relaxing inside the ...

  7. Getting an MRI (For Kids)

    MedlinePlus

    ... Happens in the Operating Room? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) A A A en español Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed ...

  8. Contrast agents for MRI.

    PubMed

    Shokrollahi, H

    2013-12-01

    Contrast agents are divided into two categories. The first one is paramagnetic compounds, including lanthanides like gadolinium, which mainly reduce the longitudinal (T1) relaxation property and result in a brighter signal. The second class consists of super-paramagnetic magnetic nanoparticles (SPMNPs) such as iron oxides, which have a strong effect on the transversal (T2) relaxation properties. SPMNPs have the potential to be utilized as excellent probes for magnetic resonance imaging (MRI). For instance, clinically benign iron oxide and engineered ferrite nanoparticles provide a good MRI probing capability for clinical applications. Furthermore, the limited magnetic property and inability to escape from the reticuloendothelial system (RES) of the used nanoparticles impede their further advancement. Therefore, it is necessary to develop the engineered magnetic nanoparticle probes for the next-generation molecular MRI. Considering the importance of MRI in diagnosing diseases, this paper presents an overview of recent scientific achievements in the development of new synthetic SPMNP probes whereby the sensitive and target-specific observation of biological events at the molecular and cellular levels is feasible.

  9. 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

  10. 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.

  11. Efficacy of subcutaneous interferon β-1a on MRI outcomes in a randomised controlled trial of patients with clinically isolated syndromes

    PubMed Central

    De Stefano, Nicola; Comi, Giancarlo; Kappos, Ludwig; Freedman, Mark S; Polman, Chris H; Uitdehaag, Bernard M J; Hennessy, Brian; Casset-Semanaz, Florence; Lehr, Lorenz; Stubinski, Bettina; Jack, Dominic L; Barkhof, Frederik

    2014-01-01

    Aim The REbif FLEXible dosing in early MS (REFLEX) study compared several brain MRI outcomes in patients presenting with clinically isolated syndromes suggestive of multiple sclerosis and treated with two dose-frequencies of subcutaneous interferon (IFN) β-1a or placebo. Methods Patients were randomised (1:1:1) to IFN β-1a, 44 µg subcutaneously three times a week or once a week, or placebo three times a week for up to 24 months. MRI scans were performed every 3 months, or every 6 months if the patient developed clinically definite multiple sclerosis. End points analysed included: number of combined unique active lesions per patient per scan; numbers and volumes of new T2, T1 hypointense and gadolinium-enhancing (Gd+) lesions per patient per scan; and brain volume. Results 517 patients were randomised (intent-to-treat population: subcutaneous IFN β-1a three times a week, n=171; subcutaneous IFN β-1a once a week, n=175; placebo, n=171). Combined unique active lesions were lower in patients treated with subcutaneous IFN β-1a versus placebo (mean (SD) lesions per patient per scan: three times a week 0.6 (1.15); once a week 1.23 (4.26); placebo 2.70 (5.23); reduction versus placebo: three times a week 81%; once a week 63%; p<0.001) and with three times a week versus once a week (48% reduction; p=0.002). The mean numbers of new T2, T1 hypointense and Gd+ lesions were all significantly lower in the two active treatment arms compared with placebo (p≤0.004 for three times a week or once a week) and in the three times a week group compared with once a week (p≤0.012). Conclusions Both subcutaneous IFN β-1a 44 µg regimens improved MRI outcomes versus placebo, with the three times a week regimen having a more pronounced effect than once a week dosing. Trial registration clinicaltrial.gov identifier, NCT00404352. PMID:24292999

  12. 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

  13. 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

  14. Cyclic generalized projection MRI.

    PubMed

    Sarty, Gordon E

    2015-04-01

    Progress in the development of portable MRI hinges on the ability to use lightweight magnets that have non-uniform magnetic fields. An image encoding method and mathematical procedure for recovering the image from the NMR signal from non-uniform magnets with closed isomagnetic contours is given. Individual frequencies in an NMR signal from an object in a non-uniform magnetic field give rise to integrals of the object along contours of constant magnetic field: generalized projections. With closed isomagnetic field contours a simple, cyclic, direct reconstruction of the image from the generalized projections is possible when the magnet and RF transmit coil are held fixed relative to the imaged object while the RF receive coil moves. Numerical simulations, using the Shepp and Logan mathematical phantom, were completed to show that the mathematical method works and to illustrate numerical limitations. The method is numerically verified and exact reconstruction demonstrated for discrete mathematical image phantoms. Correct knowledge of the RF receive field is necessary or severe image distortions will result. The cyclic mathematical reconstruction method presented here will be useful for portable MRI schemes that use non-uniform magnets with closed isomagnetic contours along with mechanically or electronically moving the RF receive coils.

  15. MRI atlas of ectopic endometriosis.

    PubMed

    Dallaudière, B; Salut, C; Hummel, V; Pouquet, M; Piver, P; Rouanet, J-P; Maubon, A

    2013-03-01

    Ectopic endometriosis is a common condition which is often underdiagnosed, where MRI can help make a diagnosis simply, non-invasively and without irradiation. However, imagery signs of it are enormously polymorphic with a wide range of possible locations. In this paper, we have tried to illustrate comprehensively all its MRI appearances depending on the different locations where it occurs.

  16. MRI findings in Hirayama disease.

    PubMed

    Raval, Monali; Kumari, Rima; Dung, Aldrin Anthony Dung; Guglani, Bhuvnesh; Gupta, Nitij; Gupta, Rohit

    2010-11-01

    The objective of the study was to study the magnetic resonance imaging (MRI) features of Hirayama disease on a 3 Tesla MRI scanner. Nine patients with clinically suspected Hirayama disease were evaluated with neutral position, flexion, contrast-enhanced MRI and fast imaging employing steady-state acquisition (FIESTA) sequences. The spectrum of MRI features was evaluated and correlated with the clinical and electromyography findings. MRI findings of localized lower cervical cord atrophy (C5-C7), abnormal curvature, asymmetric cord flattening, loss of attachment of the dorsal dural sac and subjacent laminae in the neutral position, anterior displacement of the dorsal dura on flexion and a prominent epidural space were revealed in all patients on conventional MRI as well as with the dynamic 3D-FIESTA sequence. Intramedullary hyperintensity was seen in four patients on conventional MRI and on the 3D-FIESTA sequence. Flow voids were seen in four patients on conventional MRI sequences and in all patients with the 3D-FIESTA sequence. Contrast enhancement of the epidural component was noted in all the five patients with thoracic extensions. The time taken for conventional and contrast-enhanced MRI was about 30-40 min, while that for the 3D-FIESTA sequence was 6 min. Neutral and flexion position MRI and the 3D-FIESTA sequence compliment each other in displaying the spectrum of findings in Hirayama disease. A flexion study should form an essential part of the screening protocol in patients with suspected Hirayama disease. Newer sequences such as the 3D-FIESTA may help in reducing imaging time and obviating the need for contrast.

  17. MRI of plants and foods.

    PubMed

    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.

  18. MRI in ocular drug delivery

    PubMed Central

    Li, S. Kevin; Lizak, Martin J.; Jeong, Eun-Kee

    2008-01-01

    Conventional pharmacokinetic methods for studying ocular drug delivery are invasive and cannot be conveniently applied to humans. The advancement of MRI technology has provided new opportunities in ocular drug-delivery research. MRI provides a means to non-invasively and continuously monitor ocular drug-delivery systems with a contrast agent or compound labeled with a contrast agent. It is a useful technique in pharmacokinetic studies, evaluation of drug-delivery methods, and drug-delivery device testing. Although the current status of the technology presents some major challenges to pharmaceutical research using MRI, it has a lot of potential. In the past decade, MRI has been used to examine ocular drug delivery via the subconjunctival route, intravitreal injection, intrascleral injection to the suprachoroidal space, episcleral and intravitreal implants, periocular injections, and ocular iontophoresis. In this review, the advantages and limitations of MRI in the study of ocular drug delivery are discussed. Different MR contrast agents and MRI techniques for ocular drug-delivery research are compared. Ocular drug-delivery studies using MRI are reviewed. PMID:18186077

  19. Postprocessing techniques for gadolinium-enhanced three-dimensional MR angiography.

    PubMed

    Davis, C P; Hany, T F; Wildermuth, S; Schmidt, M; Debatin, J F

    1997-01-01

    Contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography is rapidly gaining acceptance as a versatile noninvasive alternative to conventional angiography. The technique has proved useful in the visualization and assessment of complex pathologic entities in the thoracic and abdominal aorta, renal arteries, pelvic arterial system, and pulmonary arteries. Several postprocessing techniques are available for reformation of the imaging data, including maximum intensity projection (MIP), surface rendering, and virtual intraluminal endoscopy (VIE). MIP and subvolume MIP reconstructions can be produced quickly and are useful for demonstration and archiving purposes. Because of its unique ability to display vessels without overlap, surface rendering is especially useful in depicting diseases that influence either the outer shape of the vessels or their topographic arrangement. VIE allows assessment of the inside of the vascular wall and is helpful in detecting wall-bound thrombus and evaluating the degree of stenosis. Most clinically relevant questions (eg, presence of pulmonary embolism, aortic aneurysm, renal artery stenosis) can be fully answered if analysis is based on MIP and thin multiplanar reformations of contrast-enhanced 3D MR angiograms. In some cases, the use of additional postprocessing techniques enhances diagnostic confidence.

  20. Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

    PubMed

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

    2012-12-01

    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.

  1. Gadolinium-enhanced computed tomography cystogram to diagnose bladder augment rupture in patients with iodine sensitivity.

    PubMed

    Newport, John Paul; Dusseault, Beau N; Butler, Carina; Pais, Vernon M

    2008-05-01

    Anaphylactic reaction to iodinated contrast is a potentially life-threatening complication of diagnostic imaging studies. We report the successful use of gadolinium as an alternative contrast agent for computed tomography cystogram in a patient with a history of anaphylactic reaction to iodinated contrast. This technique allowed us rapidly to diagnose a rupture of her bladder augmentation and pursue operative repair.

  2. 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…

  3. 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.

  4. MRI Technologies in Recent Human Brain Mapping

    NASA Astrophysics Data System (ADS)

    Sasaki, Yuka

    The recent magnetic resonance imaging (MRI) technology and techniques used in human brain mapping are remarkable. They are getting, faster, stronger and better. The advanced MRI technologies and techniques include, but not to limited to, the magnetic resonance imaging at higher magnetic field strengths, diffusion tensor imaging, multimodal neuroimaging, and monkey functional MRI. In this article, these advanced MRI techniques are briefly overviewed.

  5. [Standartization of MRI studies in multiple sclerosis].

    PubMed

    Bryukhov, V V; Krotenkova, I A; Morozova, S N; Krotenkova, M V

    2016-01-01

    The use of magnetic resonance imaging (MRI) in patients with multiple sclerosis has markedly increased in recent years. The main task of the MRI studies after the diagnosis of multiple sclerosis is to assess the dynamics of MRI for determining disease progression and monitoring the efficacy of therapy. In this regard, it is very important to obtain the most identical baseline and follow-up MRI that is possible when a single standard protocol is used. This article presents the protocol of brain MRI and spinal cord MRI and interpretation of MRI studies in patients with multiple sclerosis.

  6. 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…

  7. 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

  8. Arteriovenous fistula complication following MRI

    PubMed Central

    Kirkman, Danielle; Junglee, Naushad; Mullins, Paul; Macdonald, Jamie Hugo

    2012-01-01

    Health professionals should be aware of medical procedures that cause vascular access complications. This case describes a haemodialysis patient who experienced pain, swelling and bruising over a radiocephalic fistula following MRI. Exactly the same signs and symptoms were evident following a second scan performed 3 months later. Plausible explanations include a radio frequency-induced electrical current being formed at the arteriovenous fistula, or varying gradients of the MRI sequence stimulating peripheral nerves, leading to a site of increased tissue stimulation. Of note, a juxta-anastomotic venous stenosis was confirmed by fistulogram 4 days after the second scan, although whether this access failure was due to the MRI scan per se could not be ascertained. Nevertheless, these previously undocumented observations suggest that careful patient and fistula monitoring is required when completing MRI scans in those with an arteriovenous fistula. PMID:22927271

  9. MRI of the Musculoskeletal System

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  10. Magnetic Resonance Imaging (MRI) - Spine

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  12. Magnetic Resonance Imaging (MRI) Safety

    MedlinePlus

    ... radiation. Instead, MRI uses a powerful magnetic field, radio waves, rapidly changing magnetic fields, and a computer to ... in most of the body's tissues. The applied radio waves then cause these protons to produce signals that ...

  13. A tonsillolith seen on MRI.

    PubMed

    el-Sherif, I; Shembesh, F M

    1997-01-01

    A case of a large tonsillolith visualized by magnetic resonance imaging is presented. Although otolaryngologists are well aware of this entity, few radiologists are. The importance of distinguishing tonsilloliths from other structures by MRI is discussed.

  14. Potential Clinical Applications for Spinal Functional MRI

    PubMed Central

    Kornelsen, Jennifer; Mackey, Sean

    2010-01-01

    Functional MRI (fMRI) of the spinal cord is a noninvasive technique for obtaining information regarding spinal cord neuronal function. This article provides a brief overview of recent developments in spinal cord fMRI and outlines potential applications, as well as the limitations that must be overcome, for using spinal fMRI in the clinic. This technique is currently used for research purposes, but significant potential exists for spinal fMRI to become an important clinical tool. PMID:17504642

  15. [Recent advances in newborn MRI].

    PubMed

    Morel, B; Hornoy, P; Husson, B; Bloch, I; Adamsbaum, C

    2014-07-01

    The accurate morphological exploration of the brain is a major challenge in neonatology that advances in magnetic resonance imaging (MRI) can now provide. MRI is the gold standard if an hypoxic ischemic pathology is suspected in a full term neonate. In prematures, the specific role of MRI remains to be defined, secondary to US in any case. We present a state of the art of hardware and software technical developments in MRI. The increase in magnetic field strength (3 tesla) and the emergence of new MRI sequences provide access to new information. They both have positive and negative consequences on the daily clinical data acquisition use. The semiology of brain imaging in full term newborns and prematures is more extensive and complex and thereby more difficult to interpret. The segmentation of different brain structures in the newborn, even very premature, is now available. It is now possible to dissociate the cortex and basal ganglia from the cerebral white matter, to calculate the volume of anatomical structures, which improves the morphometric quantification and the understanding of the normal and abnormal brain development. MRI is a powerful tool to analyze the neonatal brain. The relevance of the diagnostic contribution requires an adaptation of the parameters of the sequences to acquire and of the image processing methods.

  16. Diffusion MRI in the heart

    PubMed Central

    Mekkaoui, Choukri; Reese, Timothy G.; Jackowski, Marcel P.; Bhat, Himanshu

    2015-01-01

    Diffusion MRI provides unique information on the structure, organization, and integrity of the myocardium without the need for exogenous contrast agents. Diffusion MRI in the heart, however, has proven technically challenging because of the intrinsic non‐rigid deformation during the cardiac cycle, displacement of the myocardium due to respiratory motion, signal inhomogeneity within the thorax, and short transverse relaxation times. Recently developed accelerated diffusion‐weighted MR acquisition sequences combined with advanced post‐processing techniques have improved the accuracy and efficiency of diffusion MRI in the myocardium. In this review, we describe the solutions and approaches that have been developed to enable diffusion MRI of the heart in vivo, including a dual‐gated stimulated echo approach, a velocity‐ (M 1) or an acceleration‐ (M 2) compensated pulsed gradient spin echo approach, and the use of principal component analysis filtering. The structure of the myocardium and the application of these techniques in ischemic heart disease are also briefly reviewed. The advent of clinical MR systems with stronger gradients will likely facilitate the translation of cardiac diffusion MRI into clinical use. The addition of diffusion MRI to the well‐established set of cardiovascular imaging techniques should lead to new and complementary approaches for the diagnosis and evaluation of patients with heart disease. © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd. PMID:26484848

  17. High frame rate retrospectively triggered Cine MRI for assessment of murine diastolic function.

    PubMed

    Coolen, Bram F; Abdurrachim, Desiree; Motaal, Abdallah G; Nicolay, Klaas; Prompers, Jeanine J; Strijkers, Gustav J

    2013-03-01

    To assess left ventricular (LV) diastolic function in mice with Cine MRI, a high frame rate (>60 frames per cardiac cycle) is required. For conventional electrocardiography-triggered Cine MRI, the frame rate is inversely proportional to the pulse repetition time (TR). However, TR cannot be lowered at will to increase the frame rate because of gradient hardware, spatial resolution, and signal-to-noise limitations. To overcome these limitations associated with electrocardiography-triggered Cine MRI, in this paper, we introduce a retrospectively triggered Cine MRI protocol capable of producing high-resolution high frame rate Cine MRI of the mouse heart for addressing left ventricular diastolic function. Simulations were performed to investigate the influence of MRI sequence parameters and the k-space filling trajectory in relation to the desired number of frames per cardiac cycle. An optimized protocol was applied in vivo and compared with electrocardiography-triggered Cine for which a high-frame rate could only be achieved by several interleaved acquisitions. Retrospective high frame rate Cine MRI proved superior to the interleaved electrocardiography-triggered protocols. High spatial-resolution Cine movies with frames rates up to 80 frames per cardiac cycle were obtained in 25 min. Analysis of left ventricular filling rate curves allowed accurate determination of early and late filling rates and revealed subtle impairments in left ventricular diastolic function of diabetic mice in comparison with nondiabetic mice.

  18. 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 symptoms 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.

  19. 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

  20. Cortical visual loss in posterior reversible encephalopathy syndrome in late postpartum eclampsia: case series.

    PubMed

    Karuppannasamy, Divya; Vikrant, K; Raghuram, A; Kumaar, T M Sathish

    2014-05-01

    The purpose of this study was to determine the prevalence of visual disturbances in patients with posterior reversible encephalopathy syndrome (PRES) associated with late postpartum eclampsia. We retrospectively reviewed the clinical records of late postpartum eclampsia patients with features of PRES for the presence of visual disturbances and location of radiological abnormalities. We found a higher prevalence of cortical visual loss in patients with PRES associated with late postpartum eclampsia. Bilateral symmetrical vasogenic edema of the parieto-occipital lobe was the most common magnetic resonance imaging (MRI) abnormality noted. No significant differences were observed in the extent of edema in patients with and without visual loss.

  1. 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

  2. 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.

  3. 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

  4. Coping – Late Side Effects

    Cancer.gov

    Cancer treatment can cause late side effects that may not show up for months or years after treatment. These late effects may include heart and lung problems, bone loss, eye and hearing changes, lymphedema, and other problems

  5. 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

  6. [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.

  7. 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

  8. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    MedlinePlus

    ... to 2-Year-Old Magnetic Resonance Imaging (MRI): Brain KidsHealth > For Parents > Magnetic Resonance Imaging (MRI): Brain ... child may be given headphones to listen to music or earplugs to block the noise, and will ...

  9. Early development of arterial spin labeling to measure regional brain blood flow by MRI.

    PubMed

    Koretsky, Alan P

    2012-08-15

    Two major avenues of work converged in the late 1980's and early 1990's to give rise to brain perfusion MRI. The development of anatomical brain MRI quickly had as a major goal the generation of angiograms using tricks to label flowing blood in macroscopic vessels. These ideas were aimed at getting information about microcirculatory flow as well. Over the same time course the development of in vivo magnetic resonance spectroscopy had as its primary goal the assessment of tissue function and in particular, tissue energetics. For this the measurement of the delivery of water to tissue was critical for assessing tissue oxygenation and viability. The measurement of the washin/washout of "freely" diffusible tracers by spectroscopic based techniques pointed the way for quantitative approaches to measure regional blood flow by MRI. These two avenues came together in the development of arterial spin labeling (ASL) MRI techniques to measure regional cerebral blood flow. The early use of ASL to measure brain activation to help verify BOLD fMRI led to a rapid development of ASL based perfusion MRI. Today development and applications of regional brain blood flow measurements with ASL continues to be a major area of activity.

  10. Cervical Spine MRI in Abused Infants.

    ERIC Educational Resources Information Center

    Feldman, Kenneth W.; And Others

    1997-01-01

    This study attempted to use cervical spine magnetic resonance imaging (MRI) to detect cord injury in 12 dead children with head injury from child abuse. Eighty percent of children autopsied had small cervical spine hemorrhages; MRI did not identify them and did not identify cord injury in any child studied, indicating that MRI scans are probably…

  11. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePlus

    ... provides detailed images of blood vessels in the brain—often without the need for contrast material. See the MRA page for more information. MRI can detect stroke at a very early stage by mapping the motion of water molecules in the tissue. ...

  12. Can Dynamic Contrast-Enhanced MRI (DCE-MRI) and Diffusion-Weighted MRI (DW-MRI) Evaluate Inflammation Disease

    PubMed Central

    Zhu, Jianguo; Zhang, Faming; Luan, Yun; Cao, Peng; Liu, Fei; He, Wenwen; Wang, Dehang

    2016-01-01

    Abstract The aim of the study was to investigate diagnosis efficacy of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DW-MRI) in Crohn's disease (CD). To find out the correlations between functional MRI parameters including Ktrans, Kep, Ve, Vp, and apparent diffusion coefficient (ADC) with a serologic biomarker. The relationships between pharmacokinetic parameters and ADC were also studied. Thirty-two patients with CD (22 men, 10 women; mean age: 30.5 years) and 18 healthy volunteers without any inflammatory disease (10 men, 8 women; mean age, 34.11 years) were enrolled into this approved prospective study. Pearson analysis was used to evaluate the correlation between Ktrans, Kep, Ve, Vp, and C-reactive protein (CRP), ADC, and CRP respectively. The diagnostic efficacy of the functional MRI parameters in terms of sensitivity and specificity were analyzed by receiver operating characteristic (ROC) curve analyses. Optimal cut-off values of each functional MRI parameters for differentiation of inflammatory from normal bowel were determined according to the Youden criterion. Mean value of Ktrans in the CD group was significantly higher than that of normal control group. Similar results were observed for Kep and Ve. On the contrary, the ADC value was lower in the CD group than that in the control group. Ktrans and Ve were shown to be correlated with CRP (r = 0.725, P < 0.001; r = 0.533, P = 0.002), meanwhile ADC showed negative correlation with CRP (r = −0.630, P < 0.001). There were negative correlations between the pharmacokinetic parameters and ADC, such as Ktrans to ADC (r = −0.856, P < 0.001), and Ve to ADC (r = −0.451, P = 0.01). The area under the curve (AUC) was 0.994 for Ktrans (P < 0.001), 0.905 for ADC (P < 0.001), 0.806 for Ve (P < 0.001), and 0.764 for Kep (P = 0.002). The cut-off point of the Ktrans was found to be 0.931 min–1. This value provided the best trade-off between

  13. 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

  14. 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

  15. 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.

  16. Never too late.

    PubMed

    1996-11-01

    Motivated by the belief that education has been central to Japan's economic success, Japan International Cooperation Agency (JICA) promotes universal access to quality basic education. In developing countries, school children rarely learn science through experiments. A new JICA training course, the Science Experiment in Primary Education, involved teacher trainers from Bangladesh, Myanmar, Pakistan, and Sri Lanka. Physics, chemistry, biology, geology, and astronomy experiments that require simple, inexpensive materials were taught. Another JICA project in Satkhira, Bangladesh, sought to raise the economic status of women enrolled in a dressmaking program through a year-long evening literacy class at three sites. Elementary school diplomas (available with proof to a local teacher of basic literacy and minimal arithmetic skills) are required in Bangladesh to apply for nongovernmental organization-initiated vocational schools and loans to start businesses in areas such as dressmaking, agriculture, and livestock raising. By late 1993, the female literacy program had expanded to 18 villages.

  17. 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

  18. Pathohistological Evidence of Smoldering Inflammation in Rheumatic Heart Disease with Massive Left Atrial Calcification.

    PubMed

    Shiba, Mikio; Sugano, Yasuo; Ikeda, Yoshihiko; Ishibashi-Ueda, Hatsue; Ohara, Takahiro; Hasegawa, Takuya; Kanzaki, Hideaki; Anzai, Toshihisa

    2016-01-01

    A 74-year-old man, who had a history of a mitral valve replacement for rheumatic heart disease (RHD) 30 years previously, was admitted with progressive heart failure. Massive calcification was observed around the left atrium on multidetector CT, in addition to a late gadolinium enhancement (LGE)-positive layer adjacently outside of the calcification on MRI. He underwent a second mitral valve replacement for the prosthetic valve failure. Pathohistological analyses of a tissue section of the left atrial wall from a surgical specimen revealed lymphocyte and macrophage infiltration that coincided with the LGE-positive layer on MRI, suggesting the existence of sustained active inflammation even after the long period of RHD.

  19. Noninvasive Assessment of Myocardial Viability in a Small Animal Model: Comparison of MRI, SPECT, and PET

    PubMed Central

    Thomas, Daniel; Bal, Harshali; Arkles, Jeffrey; Horowitz, James; Araujo, Luis; Acton, Paul D.; Ferrari, Victor A.

    2010-01-01

    Acute myocardial infarction (AMI) research relies increasingly on small animal models and noninvasive imaging methods such as MRI, single-photon emission computed tomography (SPECT), and positron emission tomography (PET). However, a direct comparison among these techniques for characterization of perfusion, viability, and infarct size is lacking. Rats were studied within 18–24 hr post AMI by MRI (4.7 T) and subsequently (40–48 hr post AMI) by SPECT (99Tc-MIBI) and micro-PET (18FDG). A necrosis-specific MRI contrast agent was used to detect AMI, and a fast low angle shot (FLASH) sequence was used to acquire late enhancement and functional images contemporaneously. Infarcted regions showed late enhancement, whereas corresponding radionuclide images had reduced tracer uptake. MRI most accurately depicted AMI, showing the closest correlation and agreement with triphenyl tetrazolium chloride (TTC), followed by SPECT and PET. In some animals a mismatch of reduced uptake in normal myocardium and relatively increased 18FDG uptake in the infarct border zone precluded conventional quantitative analysis. We performed the first quantitative comparison of MRI, PET, and SPECT for reperfused AMI imaging in a small animal model. MRI was superior to the other modalities, due to its greater spatial resolution and ability to detect necrotic myocardium directly. The observed 18FDG mismatch likely represents variable metabolic conditions between stunned myocardium in the infarct border zone and normal myocardium and supports the use of a standardized glucose load or glucose clamp technique for PET imaging of reperfused AMI in small animals. PMID:18228591

  20. Multimodal MRI of experimental stroke

    PubMed Central

    Duong, Timothy Q

    2014-01-01

    Stroke is the fourth leading cause of death and the leading cause of long-term disability in the United States. Brain imaging data from experimental stroke models and stroke patients have shown that there is often a gradual progression of potentially reversible ischemic injury toward infarction. Reestablishing tissue perfusion and/or treating with neuroprotective drugs in a timely fashion are expected to salvage some ischemic tissues. Diffusion-weighted imaging based on magnetic resonance imaging (MRI) in which contrast is based on water motion can detect ischemic injury within minutes after onsets, whereas computed tomography and other imaging modalities fail to detect stroke injury for at least a few hours. Along with quantitative perfusion imaging, the perfusion-diffusion mismatch which approximates the ischemic penumbra could be imaged non-invasively. This review describes recent progresses in the development and application of multimodal MRI and image analysis techniques to study ischemic tissue at risk in experimental stroke in rats. PMID:24323751

  1. Combination of dynamic (11)C-PIB PET and structural MRI improves diagnosis of Alzheimer's disease.

    PubMed

    Liu, Linwen; Fu, Liping; Zhang, Xi; Zhang, Jinming; Zhang, Xiaojun; Xu, Baixuan; Tian, Jiahe; Fan, Yong

    2015-08-30

    Structural magnetic resonance imaging (sMRI) is an established technique for measuring brain atrophy, and dynamic positron emission tomography with (11)C-Pittsburgh compound B ((11)C-PIB PET) has the potential to provide both perfusion and amyloid deposition information. It remains unclear, however, how to better combine perfusion, amyloid deposition and morphological information extracted from dynamic (11)C-PIB PET and sMRI with the goal of improving the diagnosis of Alzheimer's disease (AD) and mild cognitive impairment (MCI). We adopted a linear sparse support vector machine to build classifiers for distinguishing AD and MCI subjects from cognitively normal (CN) subjects based on different combinations of regional measures extracted from imaging data, including perfusion and amyloid deposition information extracted from early and late frames of (11)C-PIB separately, and gray matter volumetric information extracted from sMRI data. The experimental results demonstrated that the classifier built upon the combination of imaging measures extracted from early and late frames of (11)C-PIB as well as sMRI achieved the highest classification accuracy in both classification studies of AD (100%) and MCI (85%), indicating that multimodality information could aid in the diagnosis of AD and MCI.

  2. Feature extraction for MRI segmentation.

    PubMed

    Velthuizen, R P; Hall, L O; Clarke, L P

    1999-04-01

    Magnetic resonance images (MRIs) of the brain are segmented to measure the efficacy of treatment strategies for brain tumors. To date, no reproducible technique for measuring tumor size is available to the clinician, which hampers progress of the search for good treatment protocols. Many segmentation techniques have been proposed, but the representation (features) of the MRI data has received little attention. A genetic algorithm (GA) search was used to discover a feature set from multi-spectral MRI data. Segmentations were performed using the fuzzy c-means (FCM) clustering technique. Seventeen MRI data sets from five patients were evaluated. The GA feature set produces a more accurate segmentation. The GA fitness function that achieves the best results is the Wilks's lambda statistic when applied to FCM clusters. Compared to linear discriminant analysis, which requires class labels, the same or better accuracy is obtained by the features constructed from a GA search without class labels, allowing fully operator independent segmentation. The GA approach therefore provides a better starting point for the measurement of the response of a brain tumor to treatment.

  3. MRI Biomarkers in Oncology Clinical Trials

    PubMed Central

    Abramson, Richard G.; Arlinghaus, Lori; Dula, Adrienne; Quarles, C. Chad; Stokes, Ashley; Weis, Jared; Whisenant, Jennifer; Chekmenev, Eduard Y.; Zhukov, Igor; Williams, Jason; Yankeelov, Thomas

    2015-01-01

    Quantitative magnetic resonance imaging (MRI) techniques have the ability to quantitatively report various pathophysiological processes associated with cancer. These measures have been shown to provide complementary information to that typically obtained from standard morphologically based criteria (e.g., size) and, furthermore, have been shown to outperform sized based measures in certain applications. In this review, we discuss eight areas of quantitative MRI that are either currently employed in clinical trials, or are emerging as promising techniques for both diagnosing cancer as well as assessing—or even predicting—the response of cancer to various therapies. The currently employed methods include the response evaluation criteria in solid tumors (RECIST), dynamic susceptibility MRI (DSC-MRI), dynamic contrast enhanced MRI (DCE-MRI), and diffusion weighted imaging (DWI). The emerging techniques covered are chemical exchange saturation transfer MRI (CEST-MRI), elastography, hyperpolarized MRI, and multi-parameter MRI. After a brief introduction to each technique, we present a small number of illustrative applications before noting the existing limitations of each method and what must be done to move each to more routine clinical application. PMID:26613873

  4. Late, Late-Onset Group B Streptococcus Cellulitis With Bacteremia.

    PubMed

    Yokouchi, Yukako; Katsumori, Hiroshi; Koike, Yuji

    2016-01-01

    Group B streptococcus (GBS) infection remains a leading cause of serious neonatal and early infantile infection. As the infection often presents with nonspecific symptoms, and is associated with underlying bacteremia, prompt investigation and treatment is required. We report a case of late, late-onset GBS infection with bacteremia in a 94-day-old boy experiencing cellulitis of the left hand. Although late-onset disease or late, late-onset disease has been reported to be common among infants with underlying conditions such as premature birth, immunocompromised status, trauma, or among those using medical devices, no such underlying medical condition predisposed this infant to invasive GBS infection. Recent reports including the present case underscore the risk of GBS infection among previously healthy infants beyond the neonatal period. Thus, clinicians should especially be aware of unusual presentations of GBS invasive disease with bacteremia.

  5. 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

  6. 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…

  7. 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.

  8. Illusory Late Heavy Bombardments

    PubMed Central

    Boehnke, Patrick; Harrison, T. Mark

    2016-01-01

    The Late Heavy Bombardment (LHB), a hypothesized impact spike at ∼3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration. A significant portion of the evidence for the existence of the LHB comes from histograms of 40Ar/39Ar “plateau” ages (i.e., regions selected on the basis of apparent isochroneity). However, due to lunar magmatism and overprinting from subsequent impact events, virtually all Apollo-era samples show evidence for 40Ar/39Ar age spectrum disturbances, leaving open the possibility that partial 40Ar* resetting could bias interpretation of bombardment histories due to plateaus yielding misleadingly young ages. We examine this possibility through a physical model of 40Ar* diffusion in Apollo samples and test the uniqueness of the impact histories obtained by inverting plateau age histograms. Our results show that plateau histograms tend to yield age peaks, even in those cases where the input impact curve did not contain such a spike, in part due to the episodic nature of lunar crust or parent body formation. Restated, monotonically declining impact histories yield apparent age peaks that could be misinterpreted as LHB-type events. We further conclude that the assignment of apparent 40Ar/39Ar plateau ages bears an undesirably high degree of subjectivity. When compounded by inappropriate interpretations of histograms constructed from plateau ages, interpretation of apparent, but illusory, impact spikes is likely. PMID:27621460

  9. Illusory Late Heavy Bombardments.

    PubMed

    Boehnke, Patrick; Harrison, T Mark

    2016-09-27

    The Late Heavy Bombardment (LHB), a hypothesized impact spike at ∼3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration. A significant portion of the evidence for the existence of the LHB comes from histograms of (40)Ar/(39)Ar "plateau" ages (i.e., regions selected on the basis of apparent isochroneity). However, due to lunar magmatism and overprinting from subsequent impact events, virtually all Apollo-era samples show evidence for (40)Ar/(39)Ar age spectrum disturbances, leaving open the possibility that partial (40)Ar* resetting could bias interpretation of bombardment histories due to plateaus yielding misleadingly young ages. We examine this possibility through a physical model of (40)Ar* diffusion in Apollo samples and test the uniqueness of the impact histories obtained by inverting plateau age histograms. Our results show that plateau histograms tend to yield age peaks, even in those cases where the input impact curve did not contain such a spike, in part due to the episodic nature of lunar crust or parent body formation. Restated, monotonically declining impact histories yield apparent age peaks that could be misinterpreted as LHB-type events. We further conclude that the assignment of apparent (40)Ar/(39)Ar plateau ages bears an undesirably high degree of subjectivity. When compounded by inappropriate interpretations of histograms constructed from plateau ages, interpretation of apparent, but illusory, impact spikes is likely.

  10. Managing the chronically late patient.

    PubMed

    Baum, Neil

    2014-01-01

    Every practice has patients who are chronically late. This wrecks havoc with your schedule and makes you less productive. Patients can be trained to respect your time and arrive in the office on time. This article discusses several approaches to managing the chronically late patient.

  11. Anxiety disorders in late life.

    PubMed Central

    Flint, A. J.

    1999-01-01

    OBJECTIVE: To review the epidemiology, clinical characteristics, and treatment of anxiety disorders in late life. QUALITY OF EVIDENCE: Epidemiologic and comorbidity data are derived from well designed random-sample community surveys. There are virtually no controlled data specific to treatment of anxiety in the elderly. Guidelines for treating anxiety disorders in late life, therefore, must be extrapolated from results of randomized controlled trials conducted in younger patients. MAIN MESSAGE: Generalized anxiety disorder and agoraphobia account for most cases of anxiety disorder in late life. Late-onset generalized anxiety is usually associated with depressive illness and, in this situation, the primary pharmacologic treatment is antidepressant medication. Most elderly people with agoraphobia do not give a history of panic attacks; exposure therapy is the preferred treatment for agoraphobia without panic. CONCLUSIONS: Physicians need to make more use of antidepressant medication and behavioural therapy and less use of benzodiazepines in treating anxiety disorders in late life. PMID:10587775

  12. Multiparametric Breast MRI of Breast Cancer

    PubMed Central

    Rahbar, Habib; Partridge, Savannah C.

    2015-01-01

    Synopsis Breast MRI has increased in popularity over the past two decades due to evidence for its high sensitivity for cancer detection. Current clinical MRI approaches rely on the use of a dynamic contrast enhanced (DCE-MRI) acquisition that facilitates morphologic and semi-quantitative kinetic assessments of breast lesions. The use of more functional and quantitative parameters, such as pharmacokinetic features from high temporal resolution DCE-MRI, apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) on diffusion weighted MRI, and choline concentrations on MR spectroscopy, hold promise to broaden the utility of MRI and improve its specificity. However, due to wide variations in approach among centers for measuring these parameters and the considerable technical challenges, robust multicenter data supporting their routine use is not yet available, limiting current applications of many of these tools to research purposes. PMID:26613883

  13. Moyamoya disease: diagnostic accuracy of MRI.

    PubMed

    Yamada, I; Suzuki, S; Matsushima, Y

    1995-07-01

    Our purpose was to evaluate the diagnostic accuracy of MRI in moyamoya disease. We studied 30 patients with this disease, comparing MRI and angiographic findings. The diagnostic value of MRI was evaluated for occlusive lesions, collateral vessels, and parenchymal lesions. In all patients bilateral occlusion or stenosis of the supraclinoid internal carotid artery and proximal anterior and middle cerebral arteries was clearly shown by MRI, and staging of the extent of occlusion agreed with angiographic staging in 44 (73%) of 60 arteries. MRI, particularly coronal images, clearly showed basal cerebral moyamoya vessels in 54 hemispheres, and 45 of a total of 71 large leptomeningeal and transdural collateral vessels were identified. MRI also showed parenchymal lesions in 48 (80%) hemispheres, and the extent of occlusion in the anterior and posterior circulations respectively correlated with white matter and cortical and/or subcortical infarcts.

  14. Brain development in preterm infants assessed using advanced MRI techniques.

    PubMed

    Tusor, Nora; Arichi, Tomoki; Counsell, Serena J; Edwards, A David

    2014-03-01

    Infants who are born preterm have a high incidence of neurocognitive and neurobehavioral abnormalities, which may be associated with impaired brain development. Advanced magnetic resonance imaging (MRI) approaches, such as diffusion MRI (d-MRI) and functional MRI (fMRI), provide objective and reproducible measures of brain development. Indices derived from d-MRI can be used to provide quantitative measures of preterm brain injury. Although fMRI of the neonatal brain is currently a research tool, future studies combining d-MRI and fMRI have the potential to assess the structural and functional properties of the developing brain and its response to injury.

  15. 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.

  16. 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.

  17. Computerized Interpretation of Dynamic Breast MRI

    DTIC Science & Technology

    2005-05-01

    malignant and benign lesions. Keywords: Fuzzy c- means , breast cancer, contrast-enhanced MRI, tumor heterogeneity, computer-aided diag- nosis (CAD) 1...applications. tumor response to therapy[3]. Furthermore, breast MRI can In this paper, we present a fast fuzzy c- means (FCM) based be used for quantitative...use of a fuzzy c- means (FCM) algorithm for the assessment of 3-D tumor extent from contrast-enhanced magnetic resonance images (CE-MRI) of the breast

  18. 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( ...

  19. Late-life attachment.

    PubMed

    Freitas, Mélanie; Rahioui, Hassan

    2017-03-01

    Old age is likely to cause a crisis in one's life because of the vulnerabilities it brings up, acting as stressful elements disrupting the elder's feeling of security. It leads to the activation of what is called his attachment system, consisting in attachment styles and interpersonal emotional regulation strategies. To recover a higher sense of safety, the elder would refer to his attachment figures, that is to say closed people paying attention to him, showing towards him availability and consideration. However older adults particularly see their tolerance threshold lowered, regarding an accumulation of losses (true or symbolic) and stressful events within their lifetime. In a psychological and organic exhaustion phenomenon, the risk is to wear out the interpersonal emotional regulation strategies. These are as much vulnerabilities that may increase psychiatric decompensation, including depression. To resolve the tension of this period and to found a necessary secure feeling, the elder will have to redesign the attachment links previously settled and proceed to adjustments to this new context. The need of relational closeness comes back in the elders' attachment behaviour, counting on attachment figures not only to help their loneliness or dependency, but essentially to support them in a narcissist and affective way. That is why attachment theory enlightens the late life period, such as the new challenges older adults have to face. Many studies recognize its value in understanding the transition to old age, but without proposing conceptualization. We aim first to focus on attachment conception to say how much it is relevant with elderly, and then to describe specific terms of attachment within this population in order to better understand those patients. To finish, we must think about new therapeutic proposals taking into consideration the attachment perspective for a better understanding of old age transition.

  20. MRI of nasopharyngeal adenoid hypertrophy.

    PubMed

    Surov, Alexey; Ryl, Ina; Bartel-Friedrich, Sylvia; Wienke, Andreas; Kösling, Sabrina

    2016-10-01

    Nasopharyngeal adenoid hypertrophy (NAH) is a typical benign lesion. Due to involution, nasopharyngeal lymphatic tissue usually is not found in adults beyond the 30th to 40th year of life. However, occasionally NAH has been recognized after the 50th or 60th year. The aim of this study is to identify the frequency of NAH and to analyze its MRI findings in different age groups. From 2007 to 2011, 6693 MR investigations of the head were performed at our institution. MRI was obtained with a 1.5 T MRI device. NAH was identified in 18.0% of the patients. The frequency of NAH varied from 60.3% to 1.0% in the different age groups. The mean size of NAH was 23.2 ± 4.5 mm in cranio-caudal, 31.1 ± 5.2 mm in left-right, and 14.2 ± 4.1 mm in the anterior-posterior direction. The left-right and cranio-caudal sizes of NAH were largest in the 0-9 age group and decreased with age. On T1-w images most lesions (95.4%) were hypointense in comparison to the adjacent musculature. On T2-w fat-saturated images 82.4% of the lesions were hyperintense. After intravenous administration of contrast medium most lesions showed a slight enhancement (58.6%). Moderate enhancement was seen in 32.4% and a marked enhancement was identified in 9.0%. In the 0-9 age group most lesions showed a slight enhancement. Cysts within NAH were identified in 433 cases (35.9%). The frequency of cysts increased continuously with age, namely from 10.9% to 65.2%.

  1. MRI manifestations of bowler's thumb.

    PubMed

    Showalter, Martha F; Flemming, Donald J; Bernard, Stephanie A

    2011-01-01

    Bowler's thumb is a rare perineural fibrosis involving the ulnar digital nerve of the thumb. Affected patients present with pain, neuropathy, and mass lesion. The condition is caused by chronic repetitive impaction of the ulnar soft tissues of the thumb against the thumbhole of a bowling ball. In our case, MRI showed decreased signal intensity on both T1- and T2-weighted images surrounding an enlarged ulnar digital nerve of the thumb. The findings can be confused with giant-cell tumor of the tendon sheath or peripheral-nerve-sheath tumor.

  2. 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.

  3. MRI: update on technology diffusion and acquisition.

    PubMed

    Hoppszallern, S; Hughes, C; Zimmerman, R A

    1991-04-01

    Over the past three years, magnetic resonance imaging (MRI) has become accepted as a valuable diagnostic tool, and its applications continue to expand. During this time, the number of units installed in the United States doubled. By 1990 about 2,000 MRI units were in place in the United States and nearly 20 percent of the MRI-installed base was mobile, according to a research study conducted by the Hadley Hart Group (Chicago) and Drew Consultants, Inc. (Concord, MA). With the introduction of the prospective payment system, many hospitals were hesitant to spend limited capital on new technology, such as MRI. At the same time, freestanding diagnostic imaging centers were on the rise. Some hospitals and entrepreneurs who foresaw the potential of MRI in health care pioneered its use in the clinical setting. Hospitals began to examine new partnership arrangements and alternative forms of financing, so that they too could offer MRI services. By the end of 1988, the majority of hospitals offering MRI services did not own their own unit and about 40 percent of the hospitals offering MRI services were in a mobile configuration according to the Hadley Hart Group. While the technology has been diffused into 100-bed hospitals via mobile service vendors in some parts of the country, many medium-sized and large hospitals also have entered the MRI services market in this fashion. In the larger hospitals, the patient demand or need for the service often would justify acquisition of MRI, but the expense of the technology, and in many areas restrictive state health planning policies, modified purchase of MRI systems by hospitals. Mobile service vendors offered hospitals a way to startup MRI services in a limited fashion without a major capital expenditure and its associated risk. As hospitals gain experience with mobile MRI and achieve or exceed their early utilization projections, administrators are reevaluating the need to expand services to a full-time fixed site. Early fixed

  4. MRI

    MedlinePlus

    ... sweatpants and a t-shirt). Certain types of metal can cause blurry images. You will lie on ... placed artificial joints Vascular stents Worked with sheet metal in the past (you may need tests to ...

  5. Physics of MRI: a primer.

    PubMed

    Plewes, Donald B; Kucharczyk, Walter

    2012-05-01

    This article is based on an introductory lecture given for the past many years during the "MR Physics and Techniques for Clinicians" course at the Annual Meeting of the ISMRM. This introduction is not intended to be a comprehensive overview of the field, as the subject of magnetic resonance imaging (MRI) physics is large and complex. Rather, it is intended to lay a conceptual foundation by which magnetic resonance image formation can be understood from an intuitive perspective. The presentation is nonmathematical, relying on simple models that take the reader progressively from the basic spin physics of nuclei, through descriptions of how the magnetic resonance signal is generated and detected in an MRI scanner, the foundations of nuclear magnetic resonance (NMR) relaxation, and a discussion of the Fourier transform and its relation to MR image formation. The article continues with a discussion of how magnetic field gradients are used to facilitate spatial encoding and concludes with a development of basic pulse sequences and the factors defining image contrast.

  6. 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 ...

  7. Vaginal bleeding in late pregnancy

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000627.htm Vaginal bleeding in late pregnancy To use the sharing ... JavaScript. One out of 10 women will have vaginal bleeding during their 3rd trimester. At times, it ...

  8. Functional MRI using regularized parallel imaging acquisition.

    PubMed

    Lin, Fa-Hsuan; Huang, Teng-Yi; Chen, Nan-Kuei; Wang, Fu-Nien; Stufflebeam, Steven M; Belliveau, John W; Wald, Lawrence L; Kwong, Kenneth K

    2005-08-01

    Parallel MRI techniques reconstruct full-FOV images from undersampled k-space data by using the uncorrelated information from RF array coil elements. One disadvantage of parallel MRI is that the image signal-to-noise ratio (SNR) is degraded because of the reduced data samples and the spatially correlated nature of multiple RF receivers. Regularization has been proposed to mitigate the SNR loss originating due to the latter reason. Since it is necessary to utilize static prior to regularization, the dynamic contrast-to-noise ratio (CNR) in parallel MRI will be affected. In this paper we investigate the CNR of regularized sensitivity encoding (SENSE) acquisitions. We propose to implement regularized parallel MRI acquisitions in functional MRI (fMRI) experiments by incorporating the prior from combined segmented echo-planar imaging (EPI) acquisition into SENSE reconstructions. We investigated the impact of regularization on the CNR by performing parametric simulations at various BOLD contrasts, acceleration rates, and sizes of the active brain areas. As quantified by receiver operating characteristic (ROC) analysis, the simulations suggest that the detection power of SENSE fMRI can be improved by regularized reconstructions, compared to unregularized reconstructions. Human motor and visual fMRI data acquired at different field strengths and array coils also demonstrate that regularized SENSE improves the detection of functionally active brain regions.

  9. Functional MRI Using Regularized Parallel Imaging Acquisition

    PubMed Central

    Lin, Fa-Hsuan; Huang, Teng-Yi; Chen, Nan-Kuei; Wang, Fu-Nien; Stufflebeam, Steven M.; Belliveau, John W.; Wald, Lawrence L.; Kwong, Kenneth K.

    2013-01-01

    Parallel MRI techniques reconstruct full-FOV images from undersampled k-space data by using the uncorrelated information from RF array coil elements. One disadvantage of parallel MRI is that the image signal-to-noise ratio (SNR) is degraded because of the reduced data samples and the spatially correlated nature of multiple RF receivers. Regularization has been proposed to mitigate the SNR loss originating due to the latter reason. Since it is necessary to utilize static prior to regularization, the dynamic contrast-to-noise ratio (CNR) in parallel MRI will be affected. In this paper we investigate the CNR of regularized sensitivity encoding (SENSE) acquisitions. We propose to implement regularized parallel MRI acquisitions in functional MRI (fMRI) experiments by incorporating the prior from combined segmented echo-planar imaging (EPI) acquisition into SENSE reconstructions. We investigated the impact of regularization on the CNR by performing parametric simulations at various BOLD contrasts, acceleration rates, and sizes of the active brain areas. As quantified by receiver operating characteristic (ROC) analysis, the simulations suggest that the detection power of SENSE fMRI can be improved by regularized reconstructions, compared to unregularized reconstructions. Human motor and visual fMRI data acquired at different field strengths and array coils also demonstrate that regularized SENSE improves the detection of functionally active brain regions. PMID:16032694

  10. MRI endoscopy using intrinsically localized probes

    PubMed Central

    Sathyanarayana, Shashank; Bottomley, Paul A.

    2009-01-01

    Magnetic resonance imaging (MRI) is traditionally performed with fixed externally applied gradient magnetic fields and is hence intrinsically locked to the laboratory frame of reference (FoR). Here a method for high-resolution MRI that employs active, catheter-based, tiny internal probes that utilize the spatial properties of the probe itself for localization is proposed and demonstrated at 3 T. Because these properties are intrinsic to the probe, they move with it, transforming MRI from the laboratory FoR to the FoR of the device itself, analogous to an endoscope. The “MRI endoscope” can utilize loop coils and loopless antennas with modified sensitivity, in combination with adiabatic excitation by the device itself, to restrict the MRI sensitivity to a disk-shaped plane a few mm thick. Excitation with the MRI endoscope limits the eddy currents induced in the sample to an excited volume whose size is orders of magnitude below that excited by a conventional body MRI coil. Heat testing shows maximum local temperature increases of <1 °C during MRI, within regulatory guidelines. The method is demonstrated in a kiwifruit, in intact porcine and rabbit aortas, and in an atherosclerotic human iliac artery specimen, with in-plane resolution as small as 80 μm and 1.5–5 mm slice thickness. PMID:19378751

  11. Validation of Sodium MRI of Intervertebral Disc

    PubMed Central

    Wang, Chenyang; McArdle, Erin; Fenty, Matthew; Witschey, Walter; Elliott, Mark; Sochor, Matthew; Reddy, Ravinder; Borthakur, Arijitt

    2009-01-01

    Study Design This study demonstrated the diagnostic potential of sodium MRI for non-invasive quantification of PG in the intervertebral discs. Objective To determine the existence of a linear correlation between intervertebral disc [Na] measured from sodium MRI and [PG] measurement from DMMB assay. Summary of Background Data Previous studies have shown the possibility of quantifying [Na] in vivo using sodium MRI, however none has shown a direct linear correlation between [Na] measured from sodium MRI and [PG]. Methods 3D sodium MRI images of bovine discs were acquired and converted into [Na] maps. Samples were systematically removed from the discs for DMMB assay. The removal locations were photographically recorded and applied to the [Na] maps to extract the [Na] measurements for comparison. In vivo sodium MRI scans were also carried out on a pair of symptomatic and asymptomatic subjects. Results The linear regression fit of [Na] versus [PG] data yielded a significant linear correlation coefficient of 0.71. The in vivo sodium MRI image of the symptomatic subject showed significant [Na] decrease when compared to that of the asymptomatic subject. Conclusion Sodium MRI's specificity for PG in the intervertebral discs makes it a promising diagnostic tool for the earlier phase of disc degeneration. PMID:20147881

  12. 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.

  13. Anencephaly: MRI findings and pathogenetic theories.

    PubMed

    Calzolari, Ferdinando; Gambi, Beatrice; Garani, Giampaolo; Tamisari, Lalla

    2004-12-01

    We describe the MRI appearances of an anencephalic newborn who survived for 13 h; particularities of this case are male gender and the absence of other associated malformations. Moreover, we discuss the pathogenetic theories of anencephaly, correlating MRI findings with embryological data. An exencephaly-anencephaly sequence due to amnion rupture is hypothesized.

  14. [Anatomic variants of Meckel's cave on MRI].

    PubMed

    Benoudiba, F; Hadj-Rabia, M; Iffenecker, C; Fuerxer, F; Bekkali, F; Francke, J P; Doyon, D

    1998-10-01

    Magnetic resonance imaging (MRI) gives an accurate analysis of Meckel's cave variability. Images were acquired in 50 patients with several sections for anatomical comparison. Using several sections, MRI is a suitable method for better analysis of the trigeminal cistern. The most frequent findings are symmetrical trigeminal cisterns. Expansion of Meckel's cave or its disappearance has pathological significance.

  15. 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.

  16. Use of Cardiac Computed Tomography for Ventricular Volumetry in Late Postoperative Patients with Tetralogy of Fallot

    PubMed Central

    Kim, Ho Jin; Mun, Da Na; Goo, Hyun Woo; Yun, Tae-Jin

    2017-01-01

    Background Cardiac computed tomography (CT) has emerged as an alternative to magnetic resonance imaging (MRI) for ventricular volumetry. However, the clinical use of cardiac CT requires external validation. Methods Both cardiac CT and MRI were performed prior to pulmonary valve implantation (PVI) in 11 patients (median age, 19 years) who had undergone total correction of tetralogy of Fallot during infancy. The simplified contouring method (MRI) and semiautomatic 3-dimensional region-growing method (CT) were used to measure ventricular volumes. Results All volumetric indices measured by CT and MRI generally correlated well with each other, except for the left ventricular end-systolic volume index (LV-ESVI), which showed the following correlations with the other indices: the right ventricular end-diastolic volume index (RV-EDVI) (r=0.88, p<0.001), the right ventricular end-systolic volume index (RV-ESVI) (r=0.84, p=0.001), the left ventricular end-diastolic volume index (LV-EDVI) (r=0.90, p=0.001), and the LV-ESVI (r=0.55, p=0.079). While the EDVIs measured by CT were significantly larger than those measured by MRI (median RV-EDVI: 197 mL/m2 vs. 175 mL/m2, p=0.008; median LV-EDVI: 94 mL/m2 vs. 92 mL/m2, p=0.026), no significant differences were found for the RV-ESVI or LV-ESVI. Conclusion The EDVIs measured by cardiac CT were greater than those measured by MRI, whereas the ESVIs measured by CT and MRI were comparable. The volumetric characteristics of these 2 diagnostic modalities should be taken into account when indications for late PVI after tetralogy of Fallot repair are assessed. PMID:28382264

  17. NMR, MRI, and spectroscopic MRI in inhomogeneous fields

    DOEpatents

    Demas, Vasiliki; Pines, Alexander; Martin, Rachel W; Franck, John; Reimer, Jeffrey A

    2013-12-24

    A method for locally creating effectively homogeneous or "clean" magnetic field gradients (of high uniformity) for imaging (with NMR, MRI, or spectroscopic MRI) both in in-situ and ex-situ systems with high degrees of inhomogeneous field strength. THe method of imaging comprises: a) providing a functional approximation of an inhomogeneous static magnetic field strength B.sub.0({right arrow over (r)}) at a spatial position {right arrow over (r)}; b) providing a temporal functional approximation of {right arrow over (G)}.sub.shim(t) with i basis functions and j variables for each basis function, resulting in v.sub.ij variables; c) providing a measured value .OMEGA., which is an temporally accumulated dephasing due to the inhomogeneities of B.sub.0({right arrow over(r)}); and d) minimizing a difference in the local dephasing angle .phi.({right arrow over (r)},t)=.gamma..intg..sub.0.sup.t{square root over (|{right arrow over (B)}.sub.1({right arrow over (r)},t')|.sup.2+({right arrow over (r)}{right arrow over (G)}.sub.shimG.sub.shim(t')+.parallel.{right arrow over (B)}.sub.0({right arrow over (r)}).parallel..DELTA..omega.({right arrow over (r)},t'/.gamma/).sup.2)}dt'-.OMEGA. by varying the v.sub.ij variables to form a set of minimized v.sub.ij variables. The method requires calibration of the static fields prior to minimization, but may thereafter be implemented without such calibration, may be used in open or closed systems, and potentially portable systems.

  18. Activity-induced manganese-dependent MRI (AIM-MRI) and functional MRI in awake rabbits during somatosensory stimulation

    PubMed Central

    Schroeder, Matthew P.; Weiss, Craig; Procissi, Daniel; Wang, Lei; Disterhoft, John F.

    2015-01-01

    Activity-induced manganese-dependent MRI (AIM-MRI) is a powerful tool to track system-wide neural activity using high resolution, quantitative T1-weighted MRI in animal models and has significant advantages for investigating neural activity over other modalities including BOLD fMRI. With AIM-MRI, Mn2+ ions enter neurons via voltage-gated calcium channels preferentially active during the time of experimental exposure. A broad range of AIM-MRI studies using different species studying different phenomena have been performed, but few of these studies provide a systematic evaluation of the factors influencing the detection of Mn2+ such as dosage and the temporal characteristics of Mn2+ uptake. We identified an optimal dose of Mn2+ (25 mg/kg, s.c.) in order to characterize the time-course of Mn2+ accumulation in active neural regions in the rabbit. T1-weighted MRI and functional MRI were collected 0–3, 6–9, and 24–27 h post-Mn2+ injection while the vibrissae on the right side were vibrated. Significant BOLD activation in the left somatosensory (SS) cortex and left ventral posteromedial (VPM) thalamic nucleus was detected during whisker vibration. T1-weighted signal intensities were extracted from these regions, their corresponding contralateral regions and the visual cortex (to serve as controls). A significant elevation in T1-weighted signal intensity in the left SS cortex (relative to right)was evident 6–9 and 24–27 h post-Mn2+ injection while the left VPM thalamus showed a significant enhancement (relative to the right) only during the 24–27 h session. Visual cortex showed no hemispheric difference at any timepoint. Our results suggest that studies employing AIM-MRI would benefit by conducting experimental manipulations 6–24 h after subcutaneous MnCl2 injections to optimize the concentration of contrast agent in the regions active during the exposure. PMID:26589332

  19. Portable MRI developed at Los Alamos

    SciTech Connect

    Espy, Michelle

    2015-04-22

    Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are

  20. Portable MRI developed at Los Alamos

    ScienceCinema

    Espy, Michelle

    2016-07-12

    Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are

  1. ON THE ANISOTROPIC NATURE OF MRI-DRIVEN TURBULENCE IN ASTROPHYSICAL DISKS

    SciTech Connect

    Murphy, Gareth C.; Pessah, Martin E. E-mail: mpessah@nbi.dk

    2015-04-01

    The magnetorotational instability (MRI) is thought to play an important role in enabling accretion in sufficiently ionized astrophysical disks. The rate at which MRI-driven turbulence transports angular momentum is intimately related to both the strength of the amplitudes of the fluctuations on various scales and the degree of anisotropy of the underlying turbulence. This has motivated several studies to characterize the distribution of turbulent power in spectral space. In this paper we investigate the anisotropic nature of MRI-driven turbulence using a pseudo-spectral code and introduce novel ways for providing a robust characterization of the underlying turbulence. We study the growth of the MRI and the subsequent transition to turbulence via parasitic instabilities, identifying their potential signature in the late linear stage. We show that the general flow properties vary in a quasi-periodic way on timescales comparable to ∼10 inverse angular frequencies, motivating the temporal analysis of its anisotropy. We introduce a 3D tensor invariant analysis to quantify and classify the evolution of the anisotropy of the turbulent flow. This analysis shows a continuous high level of anisotropy, with brief sporadic transitions toward two- and three-component isotropic turbulent flow. This temporal-dependent anisotropy renders standard shell averaging especially when used simultaneously with long temporal averages, inadequate for characterizing MRI-driven turbulence. We propose an alternative way to extract spectral information from the turbulent magnetized flow, whose anisotropic character depends strongly on time. This consists of stacking 1D Fourier spectra along three orthogonal directions that exhibit maximum anisotropy in Fourier space. The resulting averaged spectra show that the power along each of the three independent directions differs by several orders of magnitude over most scales, except the largest ones. Our results suggest that a first

  2. Techniques for Fast Stereoscopic MRI

    PubMed Central

    Guttman, Michael A.; McVeigh, Elliot R.

    2007-01-01

    Stereoscopic MRI can impart 3D perception with only two image acquisitions. This economy over standard multiplanar 3D volume renderings allows faster frame rates, which are needed for real-time imaging applications. Real-time 3D perception may enhance the appreciation of complex anatomical structures, and may improve hand-eye coordination while manipulating a medical device during an image-guided interventional procedure. To this goal, a system is being developed to acquire and display stereoscopic MR images in real-time. A clinically used, fast gradient-recalled echo-train sequence has been modified to produce stereo image pairs. Features have been added for depth cueing, view sharing, and bulk signal suppression. A workstation was attached to a clinical MR scanner for fast data extraction, image reconstruction and stereoscopic image display. PMID:11477636

  3. Combined PET/MRI scanner

    DOEpatents

    Schlyer, David; Woody, Craig L.; Rooney, William; Vaska, Paul; Stoll, Sean; Pratte, Jean-Francois; O'Connor, Paul

    2007-10-23

    A combined PET/MRI scanner generally includes a magnet for producing a magnetic field suitable for magnetic resonance imaging, a radiofrequency (RF) coil disposed within the magnetic field produced by the magnet and a ring tomograph disposed within the magnetic field produced by the magnet. The ring tomograph includes a scintillator layer for outputting at least one photon in response to an annihilation event, a detection array coupled to the scintillator layer for detecting the at least one photon outputted by the scintillator layer and for outputting a detection signal in response to the detected photon and a front-end electronic array coupled to the detection array for receiving the detection signal, wherein the front-end array has a preamplifier and a shaper network for conditioning the detection signal.

  4. Negative MRI versus real disease.

    PubMed

    Weinberg, D A

    1996-01-01

    A 76-year-old diabetic woman presented with progressive binocular vertical diplopia and right eye pain. Examination revealed a pupil-involving partial right third cranial nerve palsy, with development of anisocoria over the course of several hours. MRI of the brain showed no mass lesion. MRA, even with retrospective review of the images, failed to clearly identify a 1 cm right posterior communicating artery aneurysm detected by subsequent conventional cerebral angiography. While MRA has been reported to be highly sensitive in cerebral aneurysm detection at some centers, other investigators have indicated less favorable data. Standardized protocols for data acquisition and meticulous attention to proper post-processing and image interpretation are essential if MRA is to supplant invasive arteriography. Currently, conventional (x-ray) angiography remains the gold standard for aneurysm detection, while MRA possesses excellent potential in this regard.

  5. Massively Parallel MRI Detector Arrays

    PubMed Central

    Keil, Boris; Wald, Lawrence L

    2013-01-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called “ultimate” SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays. PMID:23453758

  6. Feature space analysis of MRI

    NASA Astrophysics Data System (ADS)

    Soltanian-Zadeh, Hamid; Windham, Joe P.; Peck, Donald J.

    1997-04-01

    This paper presents development and performance evaluation of an MRI feature space method. The method is useful for: identification of tissue types; segmentation of tissues; and quantitative measurements on tissues, to obtain information that can be used in decision making (diagnosis, treatment planning, and evaluation of treatment). The steps of the work accomplished are as follows: (1) Four T2-weighted and two T1-weighted images (before and after injection of Gadolinium) were acquired for ten tumor patients. (2) Images were analyed by two image analysts according to the following algorithm. The intracranial brain tissues were segmented from the scalp and background. The additive noise was suppressed using a multi-dimensional non-linear edge- preserving filter which preserves partial volume information on average. Image nonuniformities were corrected using a modified lowpass filtering approach. The resulting images were used to generate and visualize an optimal feature space. Cluster centers were identified on the feature space. Then images were segmented into normal tissues and different zones of the tumor. (3) Biopsy samples were extracted from each patient and were subsequently analyzed by the pathology laboratory. (4) Image analysis results were compared to each other and to the biopsy results. Pre- and post-surgery feature spaces were also compared. The proposed algorithm made it possible to visualize the MRI feature space and to segment the image. In all cases, the operators were able to find clusters for normal and abnormal tissues. Also, clusters for different zones of the tumor were found. Based on the clusters marked for each zone, the method successfully segmented the image into normal tissues (white matter, gray matter, and CSF) and different zones of the lesion (tumor, cyst, edema, radiation necrosis, necrotic core, and infiltrated tumor). The results agreed with those obtained from the biopsy samples. Comparison of pre- to post-surgery and radiation

  7. Intra voxel analysis in MRI

    NASA Astrophysics Data System (ADS)

    Ambrosanio, Michele; Baselice, Fabio; Ferraioli, Giampaolo; Pascazio, Vito

    2014-03-01

    A new application of Compressive Sensing (CS) in Magnetic Resonance Imaging (MRI) field is presented. In particular, first results of the Intra Voxel Analysis (IVA) technique are reported. The idea is to exploit CS peculiarities in order to distinguish different contributions inside the same resolution cell, instead of reconstructing images from not fully sampled k-space acquisition. Applied to MRI field, this means the possibility of estimating the presence of different tissues inside the same voxel, i.e. in one pixel of the obtained image. In other words, the method is the first attempt, as far as we know, of achieving Spectroscopy-like results starting from each pixel of MR images. In particular, tissues are distinguished each others by evaluating their spin-spin relaxation times. Within this manuscript, first results on clinical dataset, in particular a phantom made by aqueous solution and oil and an occipital brain lesion corresponding to a metastatic breast cancer nodule, are reported. Considering the phantom dataset, in particular focusing on the slice where the separation between water and oil occurs, the methodology is able to distinguish the two components with different spin-spin relaxation times. With respect to clinical dataset,focusing on a voxel of the lesion area, the approach is able to detect the presence of two tissues, namely the healthy and the cancer related ones, while in other location outside the lesion only the healthy tissue is detected. Of course, these are the first results of the proposed methodology, further studies on different types of clinical datasets are required in order to widely validate the approach. Although few datasets have been considered, results seem both interesting and promising.

  8. Mapping human preictal and ictal haemodynamic networks using simultaneous intracranial EEG-fMRI

    PubMed Central

    Chaudhary, Umair J.; Centeno, Maria; Thornton, Rachel C.; Rodionov, Roman; Vulliemoz, Serge; McEvoy, Andrew W.; Diehl, Beate; Walker, Matthew C.; Duncan, John S.; Carmichael, David W.; Lemieux, Louis

    2016-01-01

    Accurately characterising the brain networks involved in seizure activity may have important implications for our understanding of epilepsy. Intracranial EEG-fMRI can be used to capture focal epileptic events in humans with exquisite electrophysiological sensitivity and allows for identification of brain structures involved in this phenomenon over the entire brain. We investigated ictal BOLD networks using the simultaneous intracranial EEG-fMRI (icEEG-fMRI) in a 30 year-old male undergoing invasive presurgical evaluation with bilateral depth electrode implantations in amygdalae and hippocampi for refractory temporal lobe epilepsy. One spontaneous focal electrographic seizure was recorded. The aims of the data analysis were firstly to map BOLD changes related to the ictal activity identified on icEEG and secondly to compare different fMRI modelling approaches. Visual inspection of the icEEG showed an onset dominated by beta activity involving the right amygdala and hippocampus lasting 6.4 s (ictal onset phase), followed by gamma activity bilaterally lasting 14.8 s (late ictal phase). The fMRI data was analysed using SPM8 using two modelling approaches: firstly, purely based on the visually identified phases of the seizure and secondly, based on EEG spectral dynamics quantification. For the visual approach the two ictal phases were modelled as ‘ON’ blocks convolved with the haemodynamic response function; in addition the BOLD changes during the 30 s preceding the onset were modelled using a flexible basis set. For the quantitative fMRI modelling approach two models were evaluated: one consisting of the variations in beta and gamma bands power, thereby adding a quantitative element to the visually-derived models, and another based on principal components analysis of the entire spectrogram in attempt to reduce the bias associated with the visual appreciation of the icEEG. BOLD changes related to the visually defined ictal onset phase were revealed in the medial

  9. Mapping human preictal and ictal haemodynamic networks using simultaneous intracranial EEG-fMRI.

    PubMed

    Chaudhary, Umair J; Centeno, Maria; Thornton, Rachel C; Rodionov, Roman; Vulliemoz, Serge; McEvoy, Andrew W; Diehl, Beate; Walker, Matthew C; Duncan, John S; Carmichael, David W; Lemieux, Louis

    2016-01-01

    Accurately characterising the brain networks involved in seizure activity may have important implications for our understanding of epilepsy. Intracranial EEG-fMRI can be used to capture focal epileptic events in humans with exquisite electrophysiological sensitivity and allows for identification of brain structures involved in this phenomenon over the entire brain. We investigated ictal BOLD networks using the simultaneous intracranial EEG-fMRI (icEEG-fMRI) in a 30 year-old male undergoing invasive presurgical evaluation with bilateral depth electrode implantations in amygdalae and hippocampi for refractory temporal lobe epilepsy. One spontaneous focal electrographic seizure was recorded. The aims of the data analysis were firstly to map BOLD changes related to the ictal activity identified on icEEG and secondly to compare different fMRI modelling approaches. Visual inspection of the icEEG showed an onset dominated by beta activity involving the right amygdala and hippocampus lasting 6.4 s (ictal onset phase), followed by gamma activity bilaterally lasting 14.8 s (late ictal phase). The fMRI data was analysed using SPM8 using two modelling approaches: firstly, purely based on the visually identified phases of the seizure and secondly, based on EEG spectral dynamics quantification. For the visual approach the two ictal phases were modelled as 'ON' blocks convolved with the haemodynamic response function; in addition the BOLD changes during the 30 s preceding the onset were modelled using a flexible basis set. For the quantitative fMRI modelling approach two models were evaluated: one consisting of the variations in beta and gamma bands power, thereby adding a quantitative element to the visually-derived models, and another based on principal components analysis of the entire spectrogram in attempt to reduce the bias associated with the visual appreciation of the icEEG. BOLD changes related to the visually defined ictal onset phase were revealed in the medial and

  10. Low-Cost High-Performance MRI

    PubMed Central

    Sarracanie, Mathieu; LaPierre, Cristen D.; Salameh, Najat; Waddington, David E. J.; Witzel, Thomas; Rosen, Matthew S.

    2015-01-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5–3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices. PMID:26469756

  11. Visualizing electromagnetic fields in metals by MRI

    NASA Astrophysics Data System (ADS)

    Chandrashekar, Chandrika Sefcikova; Shellikeri, Annadanesh; Chandrashekar, S.; Taylor, Erika A.; Taylor, Deanne M.

    2017-02-01

    Based upon Maxwell's equations, it has long been established that oscillating electromagnetic (EM) fields incident upon a metal surface, decay exponentially inside the conductor, leading to a virtual absence of EM fields at sufficient depths. Magnetic resonance imaging (MRI) utilizes radiofrequency (r.f.) EM fields to produce images. Here we present a visualization of a virtual EM vacuum inside a bulk metal strip by MRI, amongst several findings. At its simplest, an MRI image is an intensity map of density variations across voxels (pixels) of identical size (=Δ x Δ y Δ z ). By contrast in bulk metal MRI, we uncover that despite uniform density, intensity variations arise from differing effective elemental volumes (voxels) from different parts of the bulk metal. Further, we furnish chemical shift imaging (CSI) results that discriminate different faces (surfaces) of a metal block according to their distinct nuclear magnetic resonance (NMR) chemical shifts, which holds much promise for monitoring surface chemical reactions noninvasively. Bulk metals are ubiquitous, and MRI is a premier noninvasive diagnostic tool. Combining the two, the emerging field of bulk metal MRI can be expected to grow in importance. The findings here may impact further development of bulk metal MRI and CSI.

  12. MRI visualisation by digitally reconstructed radiographs

    NASA Astrophysics Data System (ADS)

    Serrurier, Antoine; Bönsch, Andrea; Lau, Robert; Deserno, Thomas M.

    2015-03-01

    Visualising volumetric medical images such as computed tomography and magnetic resonance imaging (MRI) on picture archiving and communication systems (PACS) clients is often achieved by image browsing in sagittal, coronal or axial views or three-dimensional (3D) rendering. This latter technique requires fine thresholding for MRI. On the other hand, computing virtual radiograph images, also referred to as digitally reconstructed radiographs (DRR), provides in a single two-dimensional (2D) image a complete overview of the 3D data. It appears therefore as a powerful alternative for MRI visualisation and preview in PACS. This study describes a method to compute DRR from T1-weighted MRI. After segmentation of the background, a histogram distribution analysis is performed and each foreground MRI voxel is labeled as one of three tissues: cortical bone, also known as principal absorber of the X-rays, muscle and fat. An intensity level is attributed to each voxel according to the Hounsfield scale, linearly related to the X-ray attenuation coefficient. Each DRR pixel is computed as the accumulation of the new intensities of the MRI dataset along the corresponding X-ray. The method has been tested on 16 T1-weighted MRI sets. Anterior-posterior and lateral DRR have been computed with reasonable qualities and avoiding any manual tissue segmentations. This proof-of-concept holds for research application for use in clinical PACS.

  13. Recommendations for Real-Time Speech MRI

    PubMed Central

    Lingala, Sajan Goud; Sutton, Brad P.; Miquel, Marc E.; Nayak, Krishna S.

    2016-01-01

    Real-time magnetic resonance imaging (RT-MRI) is being increasingly used for speech and vocal production research studies. Several imaging protocols have emerged based on advances in RT-MRI acquisition, reconstruction, and audio-processing methods. This review summarizes the state-of-the-art, discusses technical considerations, and provides specific guidance for new groups entering this field. We provide recommendations for performing RT-MRI of the upper airway. This is a consensus statement stemming from the ISMRM-endorsed Speech MRI summit held in Los Angeles, February 2014. A major unmet need identified at the summit was the need for consensus on protocols that can be easily adapted by researchers equipped with conventional MRI systems. To this end, we provide a discussion of tradeoffs in RT-MRI in terms of acquisition requirements, a priori assumptions, artifacts, computational load, and performance for different speech tasks. We provide four recommended protocols and identify appropriate acquisition and reconstruction tools. We list pointers to open-source software that facilitate implementation. We conclude by discussing current open challenges in the methodological aspects of RT-MRI of speech. PMID:26174802

  14. Low-Cost High-Performance MRI

    NASA Astrophysics Data System (ADS)

    Sarracanie, Mathieu; Lapierre, Cristen D.; Salameh, Najat; Waddington, David E. J.; Witzel, Thomas; Rosen, Matthew S.

    2015-10-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5-3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices.

  15. Language Lateralisation in Late Proficient Bilinguals: A Lexical Decision fMRI Study

    ERIC Educational Resources Information Center

    Park, Haeme R. P.; Badzakova-Trajkov, Gjurgjica; Waldie, Karen E.

    2012-01-01

    Approximately half the world's population can now speak more than one language. Understanding the neural basis of language organisation in bilinguals, and whether the cortical networks involved during language processing differ from that of monolinguals, is therefore an important area of research. A main issue concerns whether L2 (second language)…

  16. Influence of dental materials on dental MRI

    PubMed Central

    Tymofiyeva, O; Vaegler, S; Rottner, K; Boldt, J; Hopfgartner, AJ; Proff, PC; Richter, E-J; Jakob, PM

    2013-01-01

    Objectives: To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based geometric distortion method and to classify the materials from the standpoint of dMRI. Methods: A series of standard dental materials was studied on a 1.5 T MRI system using spin echo and gradient echo pulse sequences and their magnetic susceptibility was estimated using the geometric method. Measurements on samples of dental materials were supported by in vivo examples obtained in dedicated dMRI procedures. Results: The tested materials showed a range of distortion degrees. The following materials were classified as fully compatible materials that can be present even in the tooth of interest: the resin-based sealer AH Plus® (Dentsply, Maillefer, Germany), glass ionomer cement, gutta-percha, zirconium dioxide and composites from one of the tested manufacturers. Interestingly, composites provided by the other manufacturer caused relatively strong distortions and were therefore classified as compatible I, along with amalgam, gold alloy, gold–ceramic crowns, titanium alloy and NiTi orthodontic wires. Materials, the magnetic susceptibility of which differed from that of water by more than 200 ppm, were classified as non-compatible materials that should not be present in the patient’s mouth for any dMRI applications. They included stainless steel orthodontic appliances and CoCr. Conclusions: A classification of the materials that complies with the standard grouping of materials according to their magnetic susceptibility was proposed and adopted for the purposes of dMRI. The proposed classification can serve as a guideline in future dMRI research. PMID:23610088

  17. A Novel MRI Marker for Prostate Brachytherapy

    SciTech Connect

    Frank, Steven J. Stafford, R. Jason; Bankson, James A.; Li Chun; Swanson, David A.; Kudchadker, Rajat J.; Martirosyan, Karen S.

    2008-05-01

    Purpose: Magnetic resonance imaging (MRI) is the optimal imaging modality for the prostate and surrounding critical organ structures. However, on MRI, the titanium radioactive seeds used for brachytherapy appear as black holes (negative contrast) and cannot be accurately localized. We sought to develop an encapsulated contrast agent marker (ECAM) with high-signal intensity on MRI to permit accurate localization of radioactive seeds with MRI during and after prostate brachytherapy. Methods and Materials: We investigated several agents with paramagnetic and superparamagnetic properties. The agents were injected into titanium, acrylic, and glass seeds, which were linked together in various combinations and imaged with MRI. The agent with the greatest T1-weighted signal was tested further in a canine prostate and agarose phantom. Studies were performed on a 1.5-T clinical MRI scanner. Results: The cobalt-chloride complex contrast (C4) agent with stoichiometry (CoCl{sub 2}){sub 0.8}(C{sub 2}H{sub 5}NO{sub 2}){sub 0.2} had the greatest T1-weighted signal (positive contrast) with a relaxivity ratio >1 (r{sub 2}/r{sub 1} = 1.21 {+-} 0.29). Acrylic-titanium and glass-titanium seed strands were clearly visualized with the encapsulated contrast agent marker. Conclusion: We have developed a novel ECAM that permits positive identification of the radioactive seeds used for prostate brachytherapy on MRI. Preclinical in vitro phantom studies and in vivo canine studies are needed to further optimize MRI sequencing techniques to facilitate MRI-based dosimetry.

  18. Synthetic quantitative MRI through relaxometry modelling

    PubMed Central

    Mohammadi, Siawoosh; Weiskopf, Nikolaus

    2016-01-01

    Abstract Quantitative MRI (qMRI) provides standardized measures of specific physical parameters that are sensitive to the underlying tissue microstructure and are a first step towards achieving maps of biologically relevant metrics through in vivo histology using MRI. Recently proposed models have described the interdependence of qMRI parameters. Combining such models with the concept of image synthesis points towards a novel approach to synthetic qMRI, in which maps of fundamentally different physical properties are constructed through the use of biophysical models. In this study, the utility of synthetic qMRI is investigated within the context of a recently proposed linear relaxometry model. Two neuroimaging applications are considered. In the first, artefact‐free quantitative maps are synthesized from motion‐corrupted data by exploiting the over‐determined nature of the relaxometry model and the fact that the artefact is inconsistent across the data. In the second application, a map of magnetization transfer (MT) saturation is synthesized without the need to acquire an MT‐weighted volume, which directly leads to a reduction in the specific absorption rate of the acquisition. This feature would be particularly important for ultra‐high field applications. The synthetic MT map is shown to provide improved segmentation of deep grey matter structures, relative to segmentation using T 1‐weighted images or R 1 maps. The proposed approach of synthetic qMRI shows promise for maximizing the extraction of high quality information related to tissue microstructure from qMRI protocols and furthering our understanding of the interrelation of these qMRI parameters. PMID:27753154

  19. MRI findings in pediatric patients with scurvy.

    PubMed

    Gulko, Edwin; Collins, Lee K; Murphy, Robyn C; Thornhill, Beverly A; Taragin, Benjamin H

    2015-02-01

    In modern times scurvy is a rarely encountered disease caused by ascorbic acid (vitamin C) deficiency. However, sporadic cases of scurvy persist, particularly within the pediatric population. Recent individual case reports highlight an increased incidence of scurvy among patients with autism or developmental delay, with isolated case reports detailing the magnetic resonance imaging (MRI) findings of scurvy in these pediatric populations. We present the MRI findings of scurvy in four patients with autism or developmental delay, and review the literature on MRI findings in pediatric patients with scurvy. Despite its rarity, the radiologist must consider scurvy in a pediatric patient with a restricted diet presenting with arthralgia or myalgia.

  20. Maximum entropy spherical deconvolution for diffusion MRI.

    PubMed

    Alexander, Daniel C

    2005-01-01

    This paper proposes a maximum entropy method for spherical deconvolution. Spherical deconvolution arises in various inverse problems. This paper uses the method to reconstruct the distribution of microstructural fibre orientations from diffusion MRI measurements. Analysis shows that the PASMRI algorithm, one of the most accurate diffusion MRI reconstruction algorithms in the literature, is a special case of the maximum entropy spherical deconvolution. Experiments compare the new method to linear spherical deconvolution, used previously in diffusion MRI, and to the PASMRI algorithm. The new method compares favourably both in simulation and on standard brain-scan data.

  1. Developments in boron magnetic resonance imaging (MRI)

    SciTech Connect

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  2. Nonvisual spatial navigation fMRI lateralizes mesial temporal lobe epilepsy in a patient with congenital blindness.

    PubMed

    Toller, Gianina; Adhimoolam, Babu; Grunwald, Thomas; Huppertz, Hans-Jürgen; König, Kristina; Jokeit, Hennric

    2015-01-01

    Nonvisual spatial navigation functional magnetic resonance imaging (fMRI) may help clinicians determine memory lateralization in blind individuals with refractory mesial temporal lobe epilepsy (MTLE). We report on an exceptional case of a congenitally blind woman with late-onset left MTLE undergoing presurgical memory fMRI. To activate mesial temporal structures despite the lack of visual memory, the patient was requested to recall familiar routes using nonvisual multisensory and verbal cues. Our findings demonstrate the diagnostic value of a nonvisual fMRI task to lateralize MTLE despite congenital blindness and may therefore contribute to the risk assessment for postsurgical amnesia in rare cases with refractory MTLE and accompanying congenital blindness.

  3. Complicated grief in late life

    PubMed Central

    Miller, Mark D.

    2012-01-01

    Complicated grief (CG) is a syndrome that affects 10% to 20% of grievers regardless of age, although proportionally more will face the death of loved ones in late life, CG is characterized by preoccupying and disabling symptoms that can persist for decades such as an inability to accept the death, intense yearning or avoidance, frequent reveries, deep sadness, crying, somatic distress, social withdrawal, and suicidal ideation. This syndrome is distinct from major depression and post-traumatic stress disorder, but CG maybe comorbid with each. This communication will focus on the impact of CG in late life (over age 60) and will include a case vignette for illustrating complicated grief therapy. PMID:22754292

  4. 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.

  5. 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

  6. Chronotype Modulates Language Processing-Related Cerebral Activity during Functional MRI (fMRI)

    PubMed Central

    Warbrick, Tracy; Shah, N. J.

    2015-01-01

    Objective Based on individual daily physiological cycles, humans can be classified as early (EC), late (LC) and intermediate (IC) chronotypes. Recent studies have verified that chronotype-specificity relates to performance on cognitive tasks: participants perform more efficiently when tested in the chronotype-specific optimal time of day than when tested in their non-optimal time. Surprisingly, imaging studies focussing on the underlying neural mechanisms of potential chronotype-specificities are sparse. Moreover, chronotype-specific alterations of language-related semantic processing have been neglected so far. Methods 16 male, healthy ECs, 16 ICs and 16 LCs participated in a fast event-related functional Magnetic Resonance Imaging (fMRI) paradigm probing semantic priming. Subjects read two subsequently presented words (prime, target) and were requested to determine whether the target word was an existing word or a non-word. Subjects were tested during their individual evening hours when homeostatic sleep pressure and circadian alertness levels are high to ensure equal entrainment. Results Chronotype-specificity is associated with task-performance and brain activation. First, ECs exhibited slower reaction times than LCs. Second, ECs showed attenuated BOLD responses in several language-related brain areas, e.g. in the left postcentral gyrus, left and right precentral gyrus and in the right superior frontal gyrus. Additionally, increased BOLD responses were revealed for LCs as compared to ICs in task-related areas, e.g. in the right inferior parietal lobule and in the right postcentral gyrus. Conclusions These findings reveal that even basic language processes are associated with chronotype-specific neuronal mechanisms. Consequently, results might change the way we schedule patient evaluations and/or healthy subjects in e.g. experimental research and adding “chronotype” as a statistical covariate. PMID:26397824

  7. MRI of neuronal plasticity in rodent models.

    PubMed

    Pelled, Galit

    2011-01-01

    Modifications in the behavior and architecture of neuronal networks are well documented to occur in association with learning and memory, as well as following injury. These plasticity mechanisms are crucial to ensure adequate processing of stimuli, and they also dictate the degree of recovery following peripheral or central nervous system injury. Nevertheless, the underlying neuronal mechanisms that determine the degree of plasticity of neuronal pathways are not fully understood. Recent developments in animal-dedicated magnetic resonance imaging (MRI) scanners and related hardware afford a high spatial and temporal resolution, making functional MRI and manganese-enhanced MRI emerging tools for studying reorganization of neuronal pathways in rodent models. Many of the observed changes in neuronal functions in rodent's brains following injury discussed here agree with clinical human fMRI findings. This demonstrates that animal model imaging can have a significant clinical impact in the neuronal plasticity and rehabilitation arenas.

  8. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    MedlinePlus

    ... cause a problem near a strong magnetic field. Electronic devices aren't permitted in the MRI room. ... child may be given headphones to listen to music or earplugs to block the noise, and will ...

  9. Magnetic Resonance Imaging (MRI) (For Parents)

    MedlinePlus

    ... such as eyeglasses, jewelry, belts, or credit cards. Electronic devices are not permitted in the MRI room. ... child may be given headphones to listen to music or earplugs to block the noise and will ...

  10. MRI of the Body (Chest, Abdomen, Pelvis)

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  11. Ultrasound- and MRI-Guided Prostate Biopsy

    MedlinePlus

    ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ... of the body being imaged, send and receive radio waves, producing signals that are detected by the coils. ...

  12. Magnetic Resonance Imaging (MRI): Dynamic Pelvic Floor

    MedlinePlus

    ... noninvasive test that uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  13. Functional lung imaging using hyperpolarized gas MRI.

    PubMed

    Fain, Sean B; Korosec, Frank R; Holmes, James H; O'Halloran, Rafael; Sorkness, Ronald L; Grist, Thomas M

    2007-05-01

    The noninvasive assessment of lung function using imaging is increasingly of interest for the study of lung diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Hyperpolarized gas MRI (HP MRI) has demonstrated the ability to detect changes in ventilation, perfusion, and lung microstructure that appear to be associated with both normal lung development and disease progression. The physical characteristics of HP gases and their application to MRI are presented with an emphasis on current applications. Clinical investigations using HP MRI to study asthma, COPD, cystic fibrosis, pediatric chronic lung disease, and lung transplant are reviewed. Recent advances in polarization, pulse sequence development for imaging with Xe-129, and prototype low magnetic field systems dedicated to lung imaging are highlighted as areas of future development for this rapidly evolving technology.

  14. An fMRI study of language lateralization in children and adults

    PubMed Central

    Szaflarski, Jerzy P.; Holland, Scott K.; Schmithorst, Vincent J.; Byars, Anna W.

    2005-01-01

    Language lateralization in the brain is dependent on family history of handedness, personal handedness, pathology, and other factors. The influence of age on language lateralization is not completely understood. Increasing left lateralization of language with age has been observed in children while the reverse has been noted in healthy young adults. It is not known whether the trend of decreasing language lateralization with age continues in the late decades of life and at what age the inflection in language lateralization trend as a function of age occurs. In this study, we examined the effect of age on language lateralization in 170 healthy right-handed children and adults ages 5 – 67 using functional MRI (fMRI) and a verb generation task. Our findings indicate that language lateralization to the dominant hemisphere increases between the ages 5 and 20 years, plateaus between 20 and 25 years, and slowly decreases between 25 and 70 years. PMID:16035047

  15. 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…

  16. Recent Advances in MRI of Articular Cartilage

    PubMed Central

    Gold, Garry E.; Chen, Christina A.; Koo, Seungbum; Hargreaves, Brian A.; Bangerter, Neal K.

    2010-01-01

    OBJECTIVE MRI is the most accurate noninvasive method available to diagnose disorders of articular cartilage. Conventional 2D and 3D approaches show changes in cartilage morphology. Faster 3D imaging methods with isotropic resolution can be reformatted into arbitrary planes for improved detection and visualization of pathology. Unique contrast mechanisms allow us to probe cartilage physiology and detect changes in cartilage macromolecules. CONCLUSION MRI has great promise as a noninvasive comprehensive tool for cartilage evaluation. PMID:19696274

  17. MRI-powered Actuators for Robotic Interventions

    PubMed Central

    Vartholomeos, Panagiotis; Qin, Lei; Dupont, Pierre E.

    2012-01-01

    This paper presents a novel actuation technology for robotically assisted MRI-guided interventional procedures. Compact and wireless, the actuators are both powered and controlled by the MRI scanner. The design concept and performance limits are described and derived analytically. Simulation and experiments in a clinical MR scanner are used to validate the analysis and to demonstrate the capability of the approach for needle biopsies. The concepts of actuator locking mechanisms and multi-axis control are also introduced. PMID:22287082

  18. Myocardial fibrosis in an veteran endurance athlete

    PubMed Central

    Wilson, Mathew; O'Hanlon, Rory; Prasad, Sanjay; Basavarajaiah, Sandeep; Stephens, Nigel; Senior, Roxy; Shaw, Anthony; Sharma, Sanjay; Whyte, Gregory

    2009-01-01

    This study reports the cardiac structure and function of a lifelong male endurance athlete, who has run over 148 000 miles, who presented with symptoms of chest discomfort, dyspnoea and loss of competitive running performance. Importantly, the athlete documented several periods of regular intensive endurance activity while suffering with flu-like symptoms. Cardiovascular MRI demonstrated a pattern of late gadolinium enhancement, which indicated myocardial scarring as a result of previous myocarditis. Myocarditis is a non-ischaemic inflammatory disease of the myocardium associated with cardiac dysfunction and arrhythmogenic substrate. The clinical course of viral myocarditis is mostly insidious with limited cardiac inflammation and dysfunction. However, as in the present case, overwhelming inflammation may occur in a subset of patients leading to myocardial fibrosis due to recurrent inflammation. PMID:21847425

  19. Fulminant myocarditis owing to high-dose interleukin-2 therapy for metastatic melanoma

    PubMed Central

    Thavendiranathan, P; Verhaert, D; Kendra, K L; Raman, S V

    2011-01-01

    High-dose interleukin-2 (IL-2) therapy may cause acute myocarditis characterised by diffuse myocardial involvement and occasionally fulminant heart failure. Cardiac MRI (CMRI) provides a comprehensive assessment of myocardial function, inflammation and injury in a single examination and has shown value in the diagnosis of myocarditis. We report a case of a 54-year-old male with metastatic melanoma who developed acute severe myocarditis with fulminant heart failure after high-dose IL-2 therapy. CMRI using a combination of T2 weighted imaging and T1 weighted late post-gadolinium enhancement techniques played a key role in establishing the diagnosis. To our knowledge we present the first case report of the combined use of T1 and T2 weighted CMRI techniques to diagnose IL-2 induced myocarditis. PMID:21511746

  20. The PRESTO technique for fMRI

    PubMed Central

    van Gelderen, P.; Duyn, J.H.; Ramsey, N.F.; Liu, G.; Moonen, C.T.W.

    2012-01-01

    In the early days of BOLD fMRI, the acquisition of T2* weighted data was greatly facilitated by rapid scan techniques such as EPI. The latter, however, was only available on a few MRI systems that were equipped with specialized hardware that allowed rapid switching of the imaging gradients. For this reason, soon after the invention of fMRI, the scan technique PRESTO was developed to make rapid T2* weighted scanning available on standard clinical scanning. This method combined echo shifting, which allows for echo times longer than the sequence repetition time, with acquisition of multiple k-space lines per excitation. These two concepts were combined in order to achieve a method fast enough for fMRI, while maintaining a sufficiently long echo time for optimal contrast. PRESTO has been primarily used for 3D scanning, which minimized the contribution of large vessels due to inflow effects. Although PRESTO is still being used today, its appeal has lessened somewhat due to increased gradient performance of modern MRI scanners. Compared to 2D EPI, PRESTO may have somewhat reduced temporal stability, which is a disadvantage for fMRI that may not outweigh the advantage of reduced inflow effects provided by 3D scanning. In this overview, the history of the development of the PRESTO is presented, followed by a qualitative comparison with EPI. PMID:22245350

  1. Emerging MRI methods in rheumatoid arthritis.

    PubMed

    Borrero, Camilo G; Mountz, James M; Mountz, John D

    2011-02-01

    New MRI techniques have been developed to assess not only the static anatomy of synovial hyperplasia, bone changes and cartilage degradation in patients with rheumatoid arthritis (RA), but also the activity of the physiological events that cause these changes. This enables an estimation of the rate of change in the synovium, bone and cartilage as a result of disease activity or in response to therapy. Typical MRI signs of RA in the pre-erosive phase include synovitis, bone marrow edema and subchondral cyst formation. Synovitis can be assessed by T2-weighted imaging, dynamic contrast-enhanced MRI or diffusion tensor imaging. Bone marrow edema can be detected on fluid-sensitive sequences such as short-tau inversion recovery or T2-weighted fast-spin echo sequences. Detection of small bone erosions in the early erosive phase using T1-weighted MRI has sensitivity comparable to CT. Numerous MRI techniques have been developed for quantitative assessment of potentially pathologic changes in cartilage composition that occur before frank morphologic changes. In this Review, we summarize the advances and new directions in the field of MRI, with an emphasis on their current state of development and application in RA.

  2. Diffusion MRI and its role in neuropsychology

    PubMed Central

    Mueller, Bryon A; Lim, Kelvin O; Hemmy, Laura; Camchong, Jazmin

    2015-01-01

    Diffusion Magnetic Resonance Imaging (dMRI) is a popular method used by neuroscientists to uncover unique information about the structural connections within the brain. dMRI is a non-invasive imaging methodology in which image contrast is based on the diffusion of water molecules in tissue. While applicable to many tissues in the body, this review focuses exclusively on the use of dMRI to examine white matter in the brain. In this review, we begin with a definition of diffusion and how diffusion is measured with MRI. Next we introduce the diffusion tensor model, the predominant model used in dMRI. We then describe acquisition issues related to acquisition parameters and scanner hardware and software. Sources of artifacts are then discussed, followed by a brief review of analysis approaches. We provide an overview of the limitations of the traditional diffusion tensor model, and highlight several more sophisticated non-tensor models that better describe the complex architecture of the brain’s white matter. We then touch on reliability and validity issues of diffusion measurements. Finally, we describe examples of ways in which dMRI has been applied to studies of brain disorders and how identified alterations relate to symptomatology and cognition. PMID:26255305

  3. Diffusion MRI and its Role in Neuropsychology.

    PubMed

    Mueller, Bryon A; Lim, Kelvin O; Hemmy, Laura; Camchong, Jazmin

    2015-09-01

    Diffusion Magnetic Resonance Imaging (dMRI) is a popular method used by neuroscientists to uncover unique information about the structural connections within the brain. dMRI is a non-invasive imaging methodology in which image contrast is based on the diffusion of water molecules in tissue. While applicable to many tissues in the body, this review focuses exclusively on the use of dMRI to examine white matter in the brain. In this review, we begin with a definition of diffusion and how diffusion is measured with MRI. Next we introduce the diffusion tensor model, the predominant model used in dMRI. We then describe acquisition issues related to acquisition parameters and scanner hardware and software. Sources of artifacts are then discussed, followed by a brief review of analysis approaches. We provide an overview of the limitations of the traditional diffusion tensor model, and highlight several more sophisticated non-tensor models that better describe the complex architecture of the brain's white matter. We then touch on reliability and validity issues of diffusion measurements. Finally, we describe examples of ways in which dMRI has been applied to studies of brain disorders and how identified alterations relate to symptomatology and cognition.

  4. Advanced flow MRI: emerging techniques and applications.

    PubMed

    Markl, M; Schnell, S; Wu, C; Bollache, E; Jarvis, K; Barker, A J; Robinson, J D; Rigsby, C K

    2016-08-01

    Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented.

  5. Toward correlating functional MRI and EEG sources

    NASA Astrophysics Data System (ADS)

    Singh, Manbir; Khosla, Deepak

    1996-04-01

    Though excellent spatial resolution (on the order of 1 mm) is obtainable in functional MRI (fMRI), its temporal resolution is limited to about 1 second by hemodynamics. On the other hand, magnetoencephalography (MEG) and electroencephalography (EEG) provide millisecond temporal resolution but a relatively crude (on the order of 1 cm) spatial resolution to localized sources. Thus, techniques that could combine the high temporal resolution of MEG or EEG with the high spatial resolution of fMRI would be of great significance in imaging the spatiotemporal distribution of neuronal activation. With the ultimate objective of combining fMRI and EEG activation studies, we have conducted experiments to determine how pixels activated in fMRI correlate with underlying EEG sources in a given subject during visual stimulation. Results of a three-subject study suggest good correlation between the center-of-gravity of activated pixels seen in fMRI and the center-of-gravity of regions localized through EEG measurements.

  6. Simultaneous EEG-fMRI reveals brain networks underlying recognition memory ERP old/new effects.

    PubMed

    Hoppstädter, Michael; Baeuchl, Christian; Diener, Carsten; Flor, Herta; Meyer, Patric

    2015-08-01

    The mapping of event-related potentials (ERP) on functional magnetic resonance imaging (fMRI) data remains difficult as scalp electroencephalography (EEG) is assumed to be largely insensitive to deep brain structures. Simultaneous recordings of EEG and fMRI might be helpful in reconciling surface ERPs with hemodynamic activations in medial temporal lobe structures related to recognition memory. EEG and imaging studies provide evidence for two independent processes underlying recognition memory, namely recollection and familiarity. Recollection reflects the conscious retrieval of contextual information about a specific episode, while familiarity refers to an acontextual feeling of knowing. Both processes were related to two spatiotemporally different ERP effects, namely the early mid-frontal old/new effect (familiarity) and the late parietal old new effect (recollection). We conducted an exploratory simultaneous EEG-fMRI study using a recognition memory paradigm to investigate which brain activations are modulated in relation to the ERP old/new effects. To this end we examined 17 participants in a yes/no recognition task with word stimuli. Single-trial amplitudes of ERP old/new effects were related to the hemodynamic signal in an EEG-informed fMRI analysis for a subset of 12 subjects. FMRI activation in the right dorsolateral prefrontal cortex and the right intraparietal sulcus was associated with the amplitude of the early frontal old/new effect (350-550ms), and activation in the right posterior hippocampus, parahippocampal cortex and retrosplenial cortex was associated with the amplitude of the late parietal old new effect (580-750ms). These results provide the first direct link between electrophysiological and hemodynamic correlates of familiarity and recollection. Moreover, these findings in healthy subjects complement data from intracranial ERP recordings in epilepsy patients and lesion studies in hypoxia patients.

  7. MRI atlas of the brain

    SciTech Connect

    Bradley, W.G. ); Bydder, G. )

    1990-01-01

    Since most radiologists will start from a basic of familiarity with pathophysiology of disease and a knowledge of cross-sectional imaging (at least in the transaxial plane), they are in a good position to recognize and diagnose many of the abnormalities we can currently see with CT. The appearance of these lesions on MRI is the basis for the majority of the images in this book. Chapters on Tumors, Infarcts and Ischemia, Demyelination and Infection. Hydrocephalus, and Pediatrics feature multiple images displaying the MR appearance of many common lesions with minimal associated text. Instead of focusing on pathophysiology, attention is directed to the variable appearance of these disease states using various MR imaging techniques. Although the MR contrast agent, Gadolinium-DTPA, has similar behavior (physiologically) to meglumine diatrizoate in CT, the MR techniques which result in optimal visualization of enhancing lesions are nonintuitive and are discussed. Similarly, the appearance of flowing blood and CSF and hemorrhage does not follow easily from a pre-existing CT base, therefore additional text has been devoted to these subjects.

  8. Gradient-Modulated PETRA MRI.

    PubMed

    Kobayashi, Naoharu; Goerke, Ute; Wang, Luning; Ellermann, Jutta; Metzger, Gregory J; Garwood, Michael

    2015-12-01

    Image blurring due to off-resonance and fast T 2(*) signal decay is a common issue in radial ultrashort echo time MRI sequences. One solution is to use a higher readout bandwidth, but this may be impractical for some techniques like pointwise encoding time reduction with radial acquisition (PETRA), which is a hybrid method of zero echo time and single point imaging techniques. Specifically, PETRA has severe specific absorption rate (SAR) and radiofrequency (RF) pulse peak power limitations when using higher bandwidths in human measurements. In this study, we introduce gradient modulation (GM) to PETRA to reduce image blurring artifacts while keeping SAR and RF peak power low. Tolerance of GM-PETRA to image blurring was evaluated in simulations and experiments by comparing with the conventional PETRA technique. We performed inner ear imaging of a healthy subject at 7T. GM-PETRA showed significantly less image blurring due to off-resonance and fast T2(*) signal decay compared to PETRA. In in vivo imaging, GM-PETRA nicely captured complex structures of the inner ear such as the cochlea and semicircular canals. Gradient modulation can improve the PETRA image quality and mitigate SAR and RF peak power limitations without special hardware modification in clinical scanners.

  9. "MRI Stealth" robot for prostate interventions.

    PubMed

    Stoianovici, Dan; Song, Danny; Petrisor, Doru; Ursu, Daniel; Mazilu, Dumitru; Muntener, Michael; Mutener, Michael; Schar, Michael; Patriciu, Alexandru

    2007-01-01

    The paper reports an important achievement in MRI instrumentation, a pneumatic, fully actuated robot located within the scanner alongside the patient and operating under remote control based on the images. Previous MRI robots commonly used piezoelectric actuation limiting their compatibility. Pneumatics is an ideal choice for MRI compatibility because it is decoupled from electromagnetism, but pneumatic actuators were hardly controllable. This achievement was possible due to a recent technology breakthrough, the invention of a new type of pneumatic motor, PneuStep 1, designed for the robot reported here with uncompromised MRI compatibility, high-precision, and medical safety. MrBot is one of the "MRI stealth" robots today (the second is described in this issue by Zangos et al.). Both of these systems are also multi-imager compatible, being able to operate with the imager of choice or cross-imaging modalities. For MRI compatibility the robot is exclusively constructed of nonmagnetic and dielectric materials such as plastics, ceramics, crystals, rubbers and is electricity free. Light-based encoding is used for feedback, so that all electric components are distally located outside the imager's room. MRI robots are modern, digital medical instruments in line with advanced imaging equipment and methods. These allow for accessing patients within closed bore scanners and performing interventions under direct (in scanner) imaging feedback. MRI robots could allow e.g. to biopsy small lesions imaged with cutting edge cancer imaging methods, or precisely deploy localized therapy at cancer foci. Our robot is the first to show the feasibility of fully automated in-scanner interventions. It is customized for the prostate and operates transperineally for needle interventions. It can accommodate various needle drivers for different percutaneous procedures such as biopsy, thermal ablations, or brachytherapy. The first needle driver is customized for fully automated low

  10. [MRI angiography of the thoracic vessels including coronary arteries: techniques and indications].

    PubMed

    Didier, D

    1999-09-01

    Because it is a non-invasive method, Magnetic Resonance Angiography has more and more indications in the thorax, particularly with the help of use of contrast media. Different types of sequences used (Cine-MR, Gradient-echo 2D and Gadolinium enhanced breath-hold and non breath-hold 3D) are described as well as acquisition parameters and reconstructions from natives images. Post-processing techniques (MIP, MPR, 3D Surface Rendering) and their limitations depending upon the region explored are explained. Major indications (congenital anomalies of the great vessels, aneurysms, dissections, post-operative studies, evaluation of coronary arteries) are illustrated and the role of MRA compared to the other invasive and non invasive modalities is discussed.

  11. Radiation induced currents in MRI RF coils: application to linac/MRI integration

    PubMed Central

    Burke, B; Fallone, B G; Rathee, S

    2010-01-01

    The integration of medical linear accelerators (linac) with magnetic resonance imaging (MRI) systems is advancing the current state of image-guided radiotherapy. The MRI in these integrated units will provide real-time, accurate tumor locations for radiotherapy treatment, thus decreasing geometric margins around tumors and reducing normal tissue damage. In the real-time operation of these integrated systems, the radiofrequency (RF) coils of MRI will be irradiated with radiation pulses from the linac. The effect of pulsed radiation on MRI radio frequency (RF) coils is not known and must be studied. The instantaneous radiation induced current (RIC) in two different MRI RF coils were measured and presented. The frequency spectra of the induced currents were calculated. Some basic characterization of the RIC was also done: isolation of the RF coil component responsible for RIC, dependence of RIC on dose rate, and effect of wax buildup placed on coil on RIC. Both the time and frequency characteristics of the RIC were seen to vary with the MRI RF coil used. The copper windings of the RF coils were isolated as the main source of RIC. A linear dependence on dose rate was seen. The RIC was decreased with wax buildup, suggesting an electronic disequilibrium as the cause of RIC. This study shows a measurable RIC present in MRI RF coils. This unwanted current could be possibly detrimental to the signal to noise ratio in MRI and produce image artifacts. PMID:20071754

  12. Multichannel Compressive Sensing MRI Using Noiselet Encoding

    PubMed Central

    Pawar, Kamlesh; Egan, Gary; Zhang, Jingxin

    2015-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding. PMID:25965548

  13. Multichannel compressive sensing MRI using noiselet encoding.

    PubMed

    Pawar, Kamlesh; Egan, Gary; Zhang, Jingxin

    2015-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding.

  14. Sodium MRI in human heart: a review.

    PubMed

    Bottomley, Paul A

    2016-02-01

    This paper offers a critical review of the properties, methods and potential clinical application of sodium ((23)Na) MRI in human heart. Because the tissue sodium concentration (TSC) in heart is about ~40 µmol/g wet weight, and the (23)Na gyromagnetic ratio and sensitivity are respectively about one-quarter and one-11th of that of hydrogen ((1)H), the signal-to-noise ratio of (23)Na MRI in the heart is about one-6000th of that of conventional cardiac (1)H MRI. In addition, as a quadrupolar nucleus, (23)Na exhibits ultra-short and multi-component relaxation behavior (T1 ~ 30 ms; T2 ~ 0.5-4 ms and 12-20 ms), which requires fast, specialized, ultra-short echo-time MRI sequences, especially for quantifying TSC. Cardiac (23)Na MRI studies from 1.5 to 7 T measure a volume-weighted sum of intra- and extra-cellular components present at cytosolic concentrations of 10-15 mM and 135-150 mM in healthy tissue, respectively, at a spatial resolution of about 0.1-1 ml in 10 min or so. Currently, intra- and extra-cellular sodium cannot be unambiguously resolved without the use of potentially toxic shift reagents. Nevertheless, increases in TSC attributable to an influx of intra-cellular sodium and/or increased extra-cellular volume have been demonstrated in human myocardial infarction consistent with prior animal studies, and arguably might also be seen in future studies of ischemia and cardiomyopathies--especially those involving defects in sodium transport. While technical implementation remains a hurdle, a central question for clinical use is whether cardiac (23)Na MRI can deliver useful information unobtainable by other more convenient methods, including (1)H MRI.

  15. Integration of EEG/MEG with MRI and fMRI in Functional Neuroimaging

    PubMed Central

    Liu, Zhongming; Ding, Lei; He, Bin

    2007-01-01

    EEG and MEG are important functional neuroimaging modalities for studying the temporal dynamics of neural activities and interactions, but the accurate localization of neural activities still remains a challenging problem. Combining EEG/MEG with MRI or/and functional MRI (fMRI) holds promise to significantly increase the spatial resolution of electromagnetic source imaging, and at the same time, allows tracing the rapid neural processes and information pathways within the brain, which cannot be achieved using these modalities in isolation. In this paper, we review some recent progresses in multimodal neuroimaging, with special emphasis on the integration of EEG, MEG with MRI and fMRI. Some examples are shown to illustrate the importance of the combined source analysis in clinical and experimental studies. PMID:16898658

  16. Late colonization of Easter Island.

    PubMed

    Hunt, Terry L; Lipo, Carl P

    2006-03-17

    Easter Island (Rapa Nui) provides a model of human-induced environmental degradation. A reliable chronology is central to understanding the cultural, ecological, and demographic processes involved. Radiocarbon dates for the earliest stratigraphic layers at Anakena, Easter Island, and analysis of previous radiocarbon dates imply that the island was colonized late, about 1200 A.D. Substantial ecological impacts and major cultural investments in monumental architecture and statuary thus began soon after initial settlement.

  17. Monomelic amyotrophy with late progression.

    PubMed

    Rowin, J; Meriggioli, M N; Cochran, E J

    2001-04-01

    Monomelic amyotrophy is a sporadic juvenile-onset disease that presents with gradual onset of weakness and atrophy in the hand muscles unilaterally. Generally, this disease is considered a 'benign' and non-progressive motor neuron disease, which stabilizes within five years of onset. We discuss a case that illustrates that monomelic amyotrophy may rarely exhibit late clinical progression to the lower extremities after a prolonged period of disease stability.

  18. The late-M dwarfs

    NASA Astrophysics Data System (ADS)

    Bessell, M. S.

    1991-02-01

    Far-red spectra and VRIJHK photometry have been obtained for a sample of late-M dwarfs selected on the basis of large reduced red magnitudes from the LHS Catalog. Half of the stars in the three faintest 1 mag bins are late-M stars, the other red stars are metallic-hydride subdwarfs. Relations between various colors for the late-M dwarfs are investigated. Of all the colors I - K most reliably correlates with spectral type. FeH bands near 9900 A are clearly seen in the spectra of all dwarf stars later than M5. Two stars cooler than VB10, and similar in temperature to LHS2924 have been identified; both have H-alpha in emission and appear variable in magnitude and R - I color; one is a flare star. The other stars are of earlier spectral type and resemble W359 and VB8. The observed MI, I - K main sequence is in good agreement with the IG theoretical main sequence of Stringfellow, and the faintest stars could be about 0.09 solar mass red dwarfs or lower mass brown dwarfs.

  19. Biomedical Applications of Sodium MRI In Vivo

    PubMed Central

    Madelin, Guillaume; Regatte, Ravinder R.

    2013-01-01

    In this article, we present an up-to-date overview of the potential biomedical applications of sodium MRI in vivo. Sodium MRI is a subject of increasing interest in translational imaging research as it can give some direct and quantitative biochemical information on the tissue viability, cell integrity and function, and therefore not only help the diagnosis but also the prognosis of diseases and treatment outcomes. It has already been applied in vivo in most of human tissues, such as brain for stroke or tumor detection and therapeutic response, in breast cancer, in articular cartilage, in muscle and in kidney, and it was shown in some studies that it could provide very useful new information not available through standard proton MRI. However, this technique is still very challenging due to the low detectable sodium signal in biological tissue with MRI and hardware/software limitations of the clinical scanners. The article is divided in three parts: (1) the role of sodium in biological tissues, (2) a short review on sodium magnetic resonance, and (3) a review of some studies on sodium MRI on different organs/diseases to date. PMID:23722972

  20. Dental MRI using wireless intraoral coils

    PubMed Central

    Ludwig, Ute; Eisenbeiss, Anne-Katrin; Scheifele, Christian; Nelson, Katja; Bock, Michael; Hennig, Jürgen; von Elverfeldt, Dominik; Herdt, Olga; Flügge, Tabea; Hövener, Jan-Bernd

    2016-01-01

    Currently, the gold standard for dental imaging is projection radiography or cone-beam computed tomography (CBCT). These methods are fast and cost-efficient, but exhibit poor soft tissue contrast and expose the patient to ionizing radiation (X-rays). The need for an alternative imaging modality e.g. for soft tissue management has stimulated a rising interest in dental magnetic resonance imaging (MRI) which provides superior soft tissue contrast. Compared to X-ray imaging, however, so far the spatial resolution of MRI is lower and the scan time is longer. In this contribution, we describe wireless, inductively-coupled intraoral coils whose local sensitivity enables high resolution MRI of dental soft tissue. In comparison to CBCT, a similar image quality with complementary contrast was obtained ex vivo. In-vivo, a voxel size of the order of 250∙250∙500 μm3 was achieved in 4 min only. Compared to dental MRI acquired with clinical equipment, the quality of the images was superior in the sensitive volume of the coils and is expected to improve the planning of interventions and monitoring thereafter. This method may enable a more accurate dental diagnosis and avoid unnecessary interventions, improving patient welfare and bringing MRI a step closer to becoming a radiation-free alternative for dental imaging. PMID:27021387

  1. Dental MRI using wireless intraoral coils

    NASA Astrophysics Data System (ADS)

    Ludwig, Ute; Eisenbeiss, Anne-Katrin; Scheifele, Christian; Nelson, Katja; Bock, Michael; Hennig, Jürgen; von Elverfeldt, Dominik; Herdt, Olga; Flügge, Tabea; Hövener, Jan-Bernd

    2016-03-01

    Currently, the gold standard for dental imaging is projection radiography or cone-beam computed tomography (CBCT). These methods are fast and cost-efficient, but exhibit poor soft tissue contrast and expose the patient to ionizing radiation (X-rays). The need for an alternative imaging modality e.g. for soft tissue management has stimulated a rising interest in dental magnetic resonance imaging (MRI) which provides superior soft tissue contrast. Compared to X-ray imaging, however, so far the spatial resolution of MRI is lower and the scan time is longer. In this contribution, we describe wireless, inductively-coupled intraoral coils whose local sensitivity enables high resolution MRI of dental soft tissue. In comparison to CBCT, a similar image quality with complementary contrast was obtained ex vivo. In-vivo, a voxel size of the order of 250•250•500 μm3 was achieved in 4 min only. Compared to dental MRI acquired with clinical equipment, the quality of the images was superior in the sensitive volume of the coils and is expected to improve the planning of interventions and monitoring thereafter. This method may enable a more accurate dental diagnosis and avoid unnecessary interventions, improving patient welfare and bringing MRI a step closer to becoming a radiation-free alternative for dental imaging.

  2. Transition from Collisionless to Collisional MRI

    SciTech Connect

    Prateek Sharma; Gregory W. Hammett; Eliot Quataert

    2003-07-24

    Recent calculations by Quataert et al. (2002) found that the growth rates of the magnetorotational instability (MRI) in a collisionless plasma can differ significantly from those calculated using MHD. This can be important in hot accretion flows around compact objects. In this paper, we study the transition from the collisionless kinetic regime to the collisional MHD regime, mapping out the dependence of the MRI growth rate on collisionality. A kinetic closure scheme for a magnetized plasma is used that includes the effect of collisions via a BGK operator. The transition to MHD occurs as the mean free path becomes short compared to the parallel wavelength 2*/k(sub)||. In the weak magnetic field regime where the Alfven and MRI frequencies w are small compared to the sound wave frequency k(sub)||c(sub)0, the dynamics are still effectively collisionless even if omega << v, so long as the collision frequency v << k(sub)||c(sub)0; for an accretion flow this requires n less than or approximately equal to *(square root of b). The low collisionality regime not only modifies the MRI growth rate, but also introduces collisionless Landau or Barnes damping of long wavelength modes, which may be important for the nonlinear saturation of the MRI.

  3. Functional MRI applications in epilepsy surgery.

    PubMed

    Beers, Craig A; Federico, Paolo

    2012-05-01

    Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique that has grown rapidly in popularity over the past decade. It is already prevalent in psychology, cognitive and basic neuroscience research and is being used increasingly as a tool for clinical decision-making in epilepsy. It has been used to determine language location and laterality in patients, sometimes eliminating the need for invasive tests. fMRI can been used pre-surgically to guide resection margins, preserving eloquent cortex. Other fMRI paradigms assessing memory, visual and somatosensory systems have limited clinical applications currently, but show great promise. Simultaneous recording of electroencephalogram (EEG) and fMRI has also provided insights into the networks underlying seizure generation and is increasingly being used in epilepsy centres. In this review, we present some of the current clinical applications for fMRI in the pre-surgical assessment of epilepsy patients, and examine a number of new techniques that may soon become clinically relevant.

  4. Low field SQUID MRI devices, components and methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H (Inventor); Hahn, Inseob (Inventor)

    2010-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  5. Low field SQUID MRI devices, components and methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2011-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  6. Low Field Squid MRI Devices, Components and Methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2013-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  7. Low Field Squid MRI Devices, Components and Methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2014-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  8. Information about the Late Effects of Polio

    MedlinePlus

    ... not included. Contact info@post-polio.org. Remember POLIO? Polio (poliomyelitis or infantile paralysis) triggers memories of ... Have you heard about the LATE EFFECTS OF POLIO? In the late 1970s, survivors of polio reported ...

  9. Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

    SciTech Connect

    Frohwein, Lynn J. Schäfers, Klaus P.; Hoerr, Verena; Faber, Cornelius

    2015-07-15

    Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

  10. Late blight – Is resistance futile?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article will provide an overview of late blight resistance research that has been done within the USDA/ARS and the University of Wisconsin-Madison. The article is meant to be an informative look at the history of late blight resistance and the ability of the late blight pathogen to overcome res...

  11. WE-B-BRD-00: MRI for Radiation Oncology

    SciTech Connect

    2015-06-15

    The use of MRI in radiation therapy is rapidly increasing. Applications vary from the MRI simulator, to the MRI fused with CT, and to the integrated MRI+RT system. Compared with the standard MRI QA, a broader scope of QA features has to be defined in order to maximize the benefits of using MRI in radiation therapy. These QA features include geometric fidelity, image registration, motion management, cross-system alignment, and hardware interference. Advanced MRI techniques require a specific type of QA, as they are being widely used in radiation therapy planning, dose calculations, post-implant dosimetry, and prognoses. A vigorous and adaptive QA program is crucial to defining the responsibility of the entire radiation therapy group and detecting deviations from the performance of high-quality treatment. As a drastic departure from CT simulation, MRI simulation requires changes in the work flow of treatment planning and image guidance. MRI guided radiotherapy platforms are being developed and commercialized to take the advantage of the advance in knowledge, technology and clinical experience. This symposium will from an educational perspective discuss the scope and specific issues related to MRI guided radiotherapy. Learning Objectives: Understand the difference between a standard and a radiotherapy-specific MRI QA program. Understand the effects of MRI artifacts (geometric distortion and motion) on radiotherapy. Understand advanced MRI techniques (ultrashort echo, fast MRI including dynamic MRI and 4DMRI, diffusion, perfusion, and MRS) and related QA. Understand the methods to prepare MRI for treatment planning (electron density assignment, multimodality image registration, segmentation and motion management). Current status of MRI guided treatment platforms. Dr. Jihong Wang has a research grant with Elekta-MRL project. Dr. Ke Sheng receives research grants from Varian Medical systems.

  12. Monkey cortex through fMRI glasses.

    PubMed

    Vanduffel, Wim; Zhu, Qi; Orban, Guy A

    2014-08-06

    In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging.

  13. Motion correction in MRI of the brain

    PubMed Central

    Godenschweger, F; Kägebein, U; Stucht, D; Yarach, U; Sciarra, A; Yakupov, R; Lüsebrink, F; Schulze, P; Speck, O

    2016-01-01

    Subject motion in MRI is a relevant problem in the daily clinical routine as well as in scientific studies. Since the beginning of clinical use of MRI, many research groups have developed methods to suppress or correct motion artefacts. This review focuses on rigid body motion correction of head and brain MRI and its application in diagnosis and research. It explains the sources and types of motion and related artefacts, classifies and describes existing techniques for motion detection, compensation and correction and lists established and experimental approaches. Retrospective motion correction modifies the MR image data during the reconstruction, while prospective motion correction performs an adaptive update of the data acquisition. Differences, benefits and drawbacks of different motion correction methods are discussed. PMID:26864183

  14. Plasma MRI Experiments at UW-Madison

    NASA Astrophysics Data System (ADS)

    Flanagan, K.; Clark, M.; Desangles, V.; Siller, R.; Wallace, J.; Weisberg, D.; Forest, C. B.

    2015-11-01

    Experiments for driving Keplerian-like flow profiles on both the Plasma Couette Experiment Upgrade (PCX-U) and the Wisconsin Plasma Astrophysics Laboratory (WiPAL) user facility are described. Instead of driving flow at the boundaries, as is typical in many liquid metal Couette experiments, a global drive is implemented. A large radial current is drawn across a small axial field generating torque across the whole profile. This global electrically driven flow is capable of producing profiles similar to Keplerian flow. PCX-U has been purposely constructed for MRI experiments, while similar experiments on the WiPAL device show the versatility of the user facility and provide a larger plasma volume. Numerical calculations show the predicted parameter spaces for exciting the MRI in these plasmas and the equilibrium flow profiles expected. In both devices, relevant MRI parameters appear to be within reach of typical operating characteristics.

  15. Alternative diagnoses at paediatric appendicitis MRI.

    PubMed

    Moore, M M; Kulaylat, A N; Brian, J M; Khaku, A; Hulse, M A; Engbrecht, B W; Methratta, S T; Boal, D K B

    2015-08-01

    As the utilization of MRI in the assessment for paediatric appendicitis increases in clinical practice, it is important to recognize alternative diagnoses as the cause of abdominal pain. The purpose of this review is to share our institution's experience using MRI in the evaluation of 510 paediatric patients presenting with suspected appendicitis over a 30 month interval (July 2011 to December 2013). An alternative diagnosis was documented in 98/510 (19.2%) patients; adnexal pathology (6.3%, n = 32), enteritis-colitis (6.3%, n = 32), and mesenteric adenitis (2.2%, n = 11) comprised the majority of cases. These common entities and other less frequent illustrative cases obtained during our overall institutional experience with MRI for suspected appendicitis are reviewed.

  16. Motion correction in MRI of the brain

    NASA Astrophysics Data System (ADS)

    Godenschweger, F.; Kägebein, U.; Stucht, D.; Yarach, U.; Sciarra, A.; Yakupov, R.; Lüsebrink, F.; Schulze, P.; Speck, O.

    2016-03-01

    Subject motion in MRI is a relevant problem in the daily clinical routine as well as in scientific studies. Since the beginning of clinical use of MRI, many research groups have developed methods to suppress or correct motion artefacts. This review focuses on rigid body motion correction of head and brain MRI and its application in diagnosis and research. It explains the sources and types of motion and related artefacts, classifies and describes existing techniques for motion detection, compensation and correction and lists established and experimental approaches. Retrospective motion correction modifies the MR image data during the reconstruction, while prospective motion correction performs an adaptive update of the data acquisition. Differences, benefits and drawbacks of different motion correction methods are discussed.

  17. Segmentation of human brain using structural MRI.

    PubMed

    Helms, Gunther

    2016-04-01

    Segmentation of human brain using structural MRI is a key step of processing in imaging neuroscience. The methods have undergone a rapid development in the past two decades and are now widely available. This non-technical review aims at providing an overview and basic understanding of the most common software. Starting with the basis of structural MRI contrast in brain and imaging protocols, the concepts of voxel-based and surface-based segmentation are discussed. Special emphasis is given to the typical contrast features and morphological constraints of cortical and sub-cortical grey matter. In addition to the use for voxel-based morphometry, basic applications in quantitative MRI, cortical thickness estimations, and atrophy measurements as well as assignment of cortical regions and deep brain nuclei are briefly discussed. Finally, some fields for clinical applications are given.

  18. Uterine cirsoid aneurysm: MRI and MRA

    SciTech Connect

    Joja, Ikuo; Asakawa, Mari; Motoyama, Kazumi

    1996-03-01

    Uterine cirsoid aneurysm is uncommon. It is important to make a diagnosis of this disease preoperatively, because repeated curettages may induce life-threatening massive genital bleeding. We present a case of a 51-year-old woman with uterine cirsoid aneurysm in whom MRI and MRA were very useful for the preoperative diagnosis. The radiologic appearances on ultrasonography, CT, conventional SE MRI, MRA, dynamic MRI, and pelvic angiography are presented. Conventional SE T1-weighted and T2-weighted images demonstrated multiple flow voids in the uterus and bilateral adnexal regions. MRA demonstrated a cluster of distinct, tortuous, and coiled vascular channels in the pelvis. MRA could obtain images almost equal to angiography and was considered to be an excellent noninvasive imaging technique for the diagnosis of uterine cirsoid aneurysm. 28 refs., 7 figs

  19. Phantom-based investigation of nonrigid registration constraints in mapping fMRI to anatomical MRI

    NASA Astrophysics Data System (ADS)

    Studholme, Colin; Constable, R. Todd; Duncan, James S.

    2000-06-01

    In previous work we have introduced an approach to improving the registration of EPI fMRI data with anatomical MRI by accounting for differences in magnetic field induced geometric distortion in the two types of MRI acquisition. In particular we began to explore the use of imaging physics based constraints in a non-rigid multi-modality registration algorithm. In this paper we present phantom based experimental work examining the behavior of different non-rigid registration constraints compared to a field map acquisition of the MRI distortion. This acquisition provides a pixel by pixel 'ground truth' estimate of the displacement field within the EPI data. In our registration based approach we employ a B-spline based estimate of the relative geometric distortion with a multi-grid optimization scheme. We maximize the normalized mutual information between the two types of MRI scans to estimate the B-Spline parameters. Using the field map estimates as a gold standard, registration estimates using no additional geometric constraints are compared to those using the spin echo based signal conservation. We also examine the use of logarithmic EPI values in the criteria to provide additional sensitivity in areas of low signal. Results indicate that registration of EPI to conventional MRI incorporating a spin echo distortion model can provide comparable estimates of geometric distortion to those from field mapping data without the need for significant additional acquisitions during each fMRI sequence.

  20. MRI of knee ligament injury and reconstruction.

    PubMed

    Farshad-Amacker, Nadja A; Potter, Hollis G

    2013-10-01

    Knee ligament instability may lead to meniscal and chondral damage, resulting in early osteoarthritis. Due to its superior soft tissue contrast and avoidance of harmful ionizing radiation, MRI has become the most important imaging modality for early recognition of structural defects of the knee joint. This review aims to the understanding of MRI appearances of knee ligament structures associated with knee instability, and to review the common patterns of altered knee mechanics that lead to ligament failure. Normal anatomy of the knee ligaments, pathologic conditions, and postsurgical appearances of the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and posterolateral corner are described.

  1. Stem Cell Therapy: MRI Guidance and Monitoring

    PubMed Central

    Kraitchman, Dara L.; Gilson, Wesley D.; Lorenz, Christine H.

    2011-01-01

    With the recent advances in magnetic resonance (MR) labeling of cellular therapeutics, it is natural that interventional MRI techniques for targeting would be developed. This review provides an overview of the current methods of stem cell labeling and the challenges that are created with respect to interventional MRI administration. In particular, stem cell therapies will require specialized, MR-compatible devices as well as integration of graphical user interfaces with pulse sequences designed for interactive, real-time delivery in many organs. Specific applications that are being developed will be reviewed as well as strategies for future translation to the clinical realm. PMID:18219684

  2. Practical MRI atlas of neonatal brain development

    SciTech Connect

    Barkovich, A.J.; Truwit, C.L.

    1990-01-01

    This book is an anatomical reference for cranial magnetic resonance imaging (MRI) studies in neonates and infants. It contains 122 clear, sharp MRI scans and drawings showing changes in the normal appearance of the brain and skull during development. Sections of the atlas depict the major processes of maturation: brain myelination, development of the corpus callosum, development of the cranial bone marrow, and iron deposition in the brain. High-quality scans illustrate how these changes appear on magnetic resonance images during various stages of development.

  3. Mesentery neurilemmoma: CT, MRI and angiographic findings.

    PubMed

    Lao, Wilson T; Yang, Shih-Hung; Chen, Chi-Long; Chan, Wing P

    2011-01-01

    Mesenteric neurilemmoma is extremely rare. We present a case of a 45-year-old man with mesenteric neurilemmoma, with CT, MRI and angiographic findings. The patient was healthy and had had no symptoms previously. CT and MRI images revealed a 2.2-cm well-defined, soft-tissue mass adjacent to the posterior border of the left lobe of the liver. The tumor mass displayed a heterogenous low signal on T2-weighted image and peripheral enhancement after gadolinium administration. Angiography showed a hypervascular mass beneath the tail of pancreas, which was supplied by small branches of middle splenic artery. Histopathology revealed a mesentery neurilemmoma composed of spindle tumor cells.

  4. In vitro MRI of brain development.

    PubMed

    Rados, Marko; Judas, Milos; Kostović, Ivica

    2006-02-01

    In this review, we demonstrate the developmental appearance, structural features, and reorganization of transient cerebral zones and structures in the human fetal brain using a correlative histological and MRI analysis. The analysis of postmortem aldehyde-fixed specimens (age range: 10 postovulatory weeks to term) revealed that, at 10 postovulatory weeks, the cerebral wall already has a trilaminar appearance and consists of: (1) a ventricular zone of high cell-packing density; (2) an intermediate zone; (3) the cortical plate (in a stage of primary consolidation) with high MRI signal intensity. The anlage of the hippocampus is present as a prominent bulging in the thin limbic telencephalon. The early fetal telencephalon impar also contains the first commissural fibers and fornix bundles in the septal area. The ganglionic eminence is clearly visible as an expanded continuation of the proliferative ventricular zone. The basal ganglia showed an initial aggregation of cells. The most massive fiber system is in the hemispheric stalk, which is in continuity with thalamocortical fibers. During the mid-fetal period (15-22 postovulatory weeks), the typical fetal lamination pattern develops and the cerebral wall consists of the following zones: (a) a marginal zone (visible on MRI exclusively in the hippocampus); (b) the cortical plate with high cell-packing density and high MRI signal intensity; (c) the subplate zone, which is the most prominent zone rich in extracellular matrix and with a very low MRI signal intensity; (d) the intermediate zone (fetal "white matter"); (e) the subventricular zone; (f) the periventricular fiber-rich zone; (g) the ventricular zone. The ganglionic eminence is still a very prominent structure with an intense proliferative activity. During the next period (22-26 postovulatory weeks), there is the developmental peak of transient MRI features, caused by the high content of hydrophyllic extracellular matrix in the subplate zone and the accumulation

  5. Antiviral efficacy of disinfectant solution MRI-1.

    PubMed

    Skinner, G R; Billstrom, M; Randall, S; Buchan, A; Davies, J; Ahmad, A

    1998-01-01

    Disinfectant MRI-1 was prepared by dissolution of non-ionic and ionic detergent in ethanol. The disinfectant inactivated extracellular and intracellular enveloped and non-enveloped viruses including herpes viruses, influenza A and human immunodeficiency disease virus in suspension or on surfaces by pre-exposure or post-exposure to the disinfectant; in addition, cells were disabled as potential hosts for viral infection using concentrations of MRI-1 which were 50-fold less than the operative concentration for disinfection. There was no evidence of in vitro mutagenicity using Salmonella typhimurium or sensitization or other adverse effect in a guinea pig model or in human subjects.

  6. Soft coincidence in late acceleration

    SciTech Connect

    Campo, Sergio del; Herrera, Ramon; Pavon, Diego

    2005-06-15

    We study the coincidence problem of late cosmic acceleration by assuming that the present ratio between dark matter and dark energy is a slowly varying function of the scale factor. As the dark energy component we consider two different candidates, first a quintessence scalar field, and then a tachyon field. In either case analytical solutions for the scale factor, the field, and the potential are derived. Both models show a good fit to the recent magnitude-redshift supernovae data. However, the likelihood contours disfavor the tachyon field model as it seems to prefer a excessively high value for the matter component.

  7. Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

    MedlinePlus

    ... If You Have Questions en español Resonancia magnética: columna lumbar What It Is Magnetic resonance imaging (MRI) ... MORE ON THIS TOPIC Magnetic Resonance Imaging (MRI): Cervical Spine Lumbar Puncture (Spinal Tap) Magnetic Resonance Imaging ( ...

  8. PET/MRI and PET/MRI/SISCOM coregistration in the presurgical evaluation of refractory focal epilepsy.

    PubMed

    Fernández, S; Donaire, A; Serès, E; Setoain, X; Bargalló, N; Falcón, C; Sanmartí, F; Maestro, I; Rumià, J; Pintor, L; Boget, T; Aparicio, J; Carreño, M

    2015-03-01

    We aimed to investigate the usefulness of coregistration of positron emission tomography (PET) and magnetic resonance imaging (MRI) findings (PET/MRI) and of coregistration of PET/MRI with subtraction ictal single-photon emission computed tomography (SPECT) coregistered to MRI (SISCOM) (PET/MRI/SISCOM) in localizing the potential epileptogenic zone in patients with drug-resistant epilepsy. We prospectively included 35 consecutive patients with refractory focal epilepsy whose presurgical evaluation included a PET study. Separately acquired PET and structural MRI images were coregistered for each patient. When possible, ictal SPECT and SISCOM were obtained and coregistered with PET/MRI. The potential location of the epileptogenic zone determined by neuroimaging was compared with the seizure onset zone determined by long-term video-EEG monitoring and with invasive EEG studies in patients who were implanted. Structural MRI showed no lesions in 15 patients. In these patients, PET/MRI coregistration showed a hypometabolic area in 12 (80%) patients that was concordant with seizure onset zone on EEG in 9. In 7 patients without MRI lesions, PET/MRI detected a hypometabolism that was undetected on PET alone. SISCOM, obtained in 25 patients, showed an area of hyperperfusion concordant with the seizure onset zone on EEG in 7 (58%) of the 12 of these patients who had normal MRI findings. SISCOM hyperperfusion was less extensive than PET hypometabolism. A total of 19 patients underwent surgery; 11 of these underwent invasive-EEG monitoring and the seizure onset zone was concordant with PET/MRI in all cases. PET/MRI/SISCOM coregistration, performed in 4 of these patients, was concordant in 3 (75%). After epilepsy surgery, 13 (68%) patients are seizure-free after a mean follow-up of 4.5 years. PET/MRI and PET/MRI/SISCOM coregistration are useful for determining the potential epileptogenic zone and thus for planning invasive EEG studies and surgery more precisely, especially in

  9. PET MRI Coregistration in Intractable Epilepsy and Gray Matter Heterotopia.

    PubMed

    Seniaray, Nikhil; Jain, Anuj

    2017-03-01

    A 25-year-old woman with intractable seizures underwent FDG PET/MRI for seizure focus localization. MRI demonstrated bilateral carpetlike nodular subependymal gray matter and asymmetrical focal dilatation in the right temporal horn. PET/MRI showed increased FDG within subependymal gray matter with significant hypometabolism in right anterior temporal lobe. EEG and ictal semiology confirmed the right temporal seizure origin. This case highlights the importance of identification of gray matter heterotopia on FDG PET/MRI.

  10. Three-dimensional, in vivo MRI with self-gating and image coregistration in the mouse.

    PubMed

    Nieman, Brian J; Szulc, Kamila U; Turnbull, Daniel H

    2009-05-01

    Motion during magnetic resonance imaging (MRI) scans routinely results in undesirable image artifact or blurring. Since high-resolution, three-dimensional (3D) imaging of the mouse requires long scan times for satisfactory signal-to-noise ratio (SNR) and image quality, motion-related artifacts are likely over much of the body and limit applications of mouse MRI. In this investigation, we explored the use of self-gated imaging methods and image coregistration for improving image quality in the presence of motion. Self-gated signal results from a modified 3D gradient-echo sequence showed detection of periodic respiratory and cardiac motion in the adult mouse-with excellent comparison to traditional measurements, sensitivity to respiration-induced tissue changes in the brain, and even detection of embryonic cardiac motion in utero. Serial image coregistration with rapidly-acquired, low-SNR volumes further enabled detection and correction of bulk changes in embryo location during in utero imaging sessions and subsequent reconstruction of high-quality images. These methods, in combination, are shown to expand the range of applications for 3D mouse MRI, enabling late-stage embryonic heart imaging and introducing the possibility of longitudinal developmental studies from embryonic stages through adulthood.

  11. [Left pulmonary agenesis diagnosed late].

    PubMed

    Deleanu, Oana; Pătraşcu, Natalia; Nebunoiu, Ana-Maria; Vintilă, V; Ulmeanu, Ruxandra; Mihălţan, F D

    2010-01-01

    We present the case of a 51 years old female-patient, with severe dextroscoliosis, having like unique symptom progressive dyspnea. The blood samples reveals polycythemia, the radiological exam shows the opacification of 2/3 of the left thorax, the absence of the lung structure in the other 1/3, the deviation of the mediastinum, and dextroscoliosis; the computed tomography reveals the absence of the left lung artery and the left airways, compensatory hyperinflation of the right lung and dilatation of the trunk and right pulmonary artery; the bronchoscopy does not visualize the carina or the left main bronchus, typical for pulmonary agenesis. Echocardiography confirmed the absence of left pulmonary artery and shows mild pulmonary hypertension (systolic pressure in the pulmonary artery of 33 mmHg) with dilatation of the right cavities, but good cinetics. We face a case of pulmonary agenesis lately diagnosed, with modest functional cardiologic implications, limited therapeutic options and good survival, justified by the late appearance of the pulmonary hypertension of low severity and without worsening in time.

  12. Multivariate Granger causality analysis of fMRI data.

    PubMed

    Deshpande, Gopikrishna; LaConte, Stephan; James, George Andrew; Peltier, Scott; Hu, Xiaoping

    2009-04-01

    This article describes the combination of multivariate Granger causality analysis, temporal down-sampling of fMRI time series, and graph theoretic concepts for investigating causal brain networks and their dynamics. As a demonstration, this approach was applied to analyze epoch-to-epoch changes in a hand-gripping, muscle fatigue experiment. Causal influences between the activated regions were analyzed by applying the directed transfer function (DTF) analysis of multivariate Granger causality with the integrated epoch response as the input, allowing us to account for the effects of several relevant regions simultaneously. Integrated responses were used in lieu of originally sampled time points to remove the effect of the spatially varying hemodynamic response as a confounding factor; using integrated responses did not affect our ability to capture its slowly varying affects of fatigue. We separately modeled the early, middle, and late periods in the fatigue. We adopted graph theoretic concepts of clustering and eccentricity to facilitate the interpretation of the resultant complex networks. Our results reveal the temporal evolution of the network and demonstrate that motor fatigue leads to a disconnection in the related neural network.

  13. Perfusion MRI: The Five Most Frequently Asked Clinical Questions

    PubMed Central

    Essig, Marco; Nguyen, Thanh Binh; Shiroishi, Mark S.; Saake, Marc; Provenzale, James M.; Enterline, David S.; Anzalone, Nicoletta; Dörfler, Arnd; Rovira, Àlex; Wintermark, Max; Law, Meng

    2013-01-01

    OBJECTIVE This article addresses questions that radiologists frequently ask when planning, performing, processing, and interpreting MRI perfusion studies in CNS imaging. CONCLUSION Perfusion MRI is a promising tool in assessing stroke, brain tumors, and neurodegenerative diseases. Most of the impediments that have limited the use of perfusion MRI can be overcome to allow integration of these methods into modern neuroimaging protocols. PMID:23971482

  14. [MRI in subacromial pathology. Report of 20 cases].

    PubMed

    Poey, C; Fajadet, P; Pages, M; Chaffai, M A; Lassoued, S; Maquin, P; Fournie, A; Mansat, M; Railhac, J J

    1990-01-01

    The authors report the results of MRI performed in 20 patients presenting clinical symptoms of subacromial pathology. The MRI results are correlated to the results of arthrography or arthro CT scan and also to surgical results. MRI is an excellent technique if a precise protocol with T2 weighted images is respected in order to visualize tears or minor perforations of the supraspinatus muscle.

  15. MRI: Is Gadolinium Safe for People with Kidney Problems?

    MedlinePlus

    ... with kidney problems? I'm scheduled for an MRI and I have kidney problems. Will I be OK having an MRI? Answers from Carl F. Anderson, M.D. It depends on the type of magnetic resonance imaging (MRI) scan you're scheduled to have — an ...

  16. Late veneer and late accretion to the terrestrial planets

    NASA Astrophysics Data System (ADS)

    Brasser, R.; Mojzsis, S. J.; Werner, S. C.; Matsumura, S.; Ida, S.

    2016-12-01

    It is generally accepted that silicate-metal ('rocky') planet formation relies on coagulation from a mixture of sub-Mars sized planetary embryos and (smaller) planetesimals that dynamically emerge from the evolving circum-solar disc in the first few million years of our Solar System. Once the planets have, for the most part, assembled after a giant impact phase, they continue to be bombarded by a multitude of planetesimals left over from accretion. Here we place limits on the mass and evolution of these planetesimals based on constraints from the highly siderophile element (HSE) budget of the Moon. Outcomes from a combination of N-body and Monte Carlo simulations of planet formation lead us to four key conclusions about the nature of this early epoch. First, matching the terrestrial to lunar HSE ratio requires either that the late veneer on Earth consisted of a single lunar-size impactor striking the Earth before 4.45 Ga, or that it originated from the impact that created the Moon. An added complication is that analysis of lunar samples indicates the Moon does not preserve convincing evidence for a late veneer like Earth. Second, the expected chondritic veneer component on Mars is 0.06 weight percent. Third, the flux of terrestrial impactors must have been low (≲10-6 M⊕ Myr-1) to avoid wholesale melting of Earth's crust after 4.4 Ga, and to simultaneously match the number of observed lunar basins. This conclusion leads to an Hadean eon which is more clement than assumed previously. Last, after the terrestrial planets had fully formed, the mass in remnant planetesimals was ∼10-3 M⊕, lower by at least an order of magnitude than most previous models suggest. Our dynamically and geochemically self-consistent scenario requires that future N-body simulations of rocky planet formation either directly incorporate collisional grinding or rely on pebble accretion.

  17. Multiscan MRI-based virtual cystoscopy

    NASA Astrophysics Data System (ADS)

    Chen, Dongqing; Li, Bin; Huang, Wei; Liang, Zach

    2000-04-01

    Computed tomography (CT) based virtual cystoscopy (VC) has been studied as a potential tool for screening bladder cancer. It is accurate in localizing tumor of size larger than 1 cm and less expensive, as compared to fiberoptic cystoscopy. However, it is invasive and difficult to perform due to using Foley catheter for bladder insufflating with air. In a previous work, we investigated a magnetic resonance imaging (MRI) based VC scheme with urine as a natural contrast solution, in which a MRI acquisition protocol and an adaptive segmentation method were utilized. Both bladder lumen and wall were successfully delineated. To suppress motion artifact and insight pathological change on the bladder wall images, a multi-scan MRI scheme was presented in this study. One transverse and another coronal acquisitions of T1-weighted that cover the whole bladder were obtained twice, at one time the bladder is full of urine and at another time it is near the empty. Four bladder volumes extracted from those 4 datasets were registered first using a flexible three- dimensional (3D) registration algorithm. Then, associated 4 lumen surfaces were viewed simultaneously with the help of an interactive 3D visualization system. This MRI-based VC was tested on volunteers and demonstrated the feasibility to mass screening for bladder cancer.

  18. MRI contrast enhancement using Magnetic Carbon Nanoparticles

    NASA Astrophysics Data System (ADS)

    Chaudhary, Rakesh P.; Kangasniemi, Kim; Takahashi, Masaya; Mohanty, Samarendra K.; Koymen, Ali R.; Department of Physics, University of Texas at Arlington Team; University of Texas Southwestern Medical Center Team

    2014-03-01

    In recent years, nanotechnology has become one of the most exciting forefront fields in cancer diagnosis and therapeutics such as drug delivery, thermal therapy and detection of cancer. Here, we report development of core (Fe)-shell (carbon) nanoparticles with enhanced magnetic properties for contrast enhancement in MRI imaging. These new classes of magnetic carbon nanoparticles (MCNPs) are synthesized using a bottom-up approach in various organic solvents, using the electric plasma discharge generated in the cavitation field of an ultrasonic horn. Gradient echo MRI images of well-dispersed MCNP-solutions (in tube) were acquired. For T2 measurements, a multi echo spin echo sequence was performed. From the slope of the 1/T2 versus concentration plot, the R2 value for different CMCNP-samples was measured. Since MCNPs were found to be extremely non-reactive, and highly absorbing in NIR regime, development of carbon-based MRI contrast enhancement will allow its simultaneous use in biomedical applications. We aim to localize the MCNPs in targeted tissue regions by external DC magnetic field, followed by MRI imaging and subsequent photothermal therapy.

  19. Challenges for Molecular Neuroimaging with MRI

    PubMed Central

    Lelyveld, Victor S.; Atanasijevic, Tatjana; Jasanoff, Alan

    2010-01-01

    Magnetic resonance (MRI)-based molecular imaging methods are beginning to have impact in neuroscience. A growing number of molecular imaging agents have been synthesized and tested in vitro, but so far relatively few have been validated in the brains of live animals. Here, we discuss key challenges associated with expanding the repertoire of successful molecular neuroimaging approaches. The difficulty of delivering agents past the blood-brain barrier (BBB) is a particular obstacle to molecular imaging in the central nervous system. We review established and emerging techniques for trans-BBB delivery, including intracranial infusion, BBB disruption, and transporter-related methods. Improving the sensitivity with which MRI-based molecular agents can be detected is a second major challenge. Better sensitivity would in turn reduce the requirements for delivery and alleviate potential side effects. We discuss recent efforts to enhance relaxivity of conventional longitudinal relaxation time (T1) and transverse relaxation time (T2) MRI contrast agents, as well as strategies that involve amplifying molecular signals or reducing endogenous background influences. With ongoing refinement of imaging approaches and brain delivery methods, MRI-based techniques for molecular-level neuroscientific investigation will fall increasingly within reach. PMID:20808721

  20. Diffusion-MRI in neurodegenerative disorders.

    PubMed

    Goveas, Joseph; O'Dwyer, Laurence; Mascalchi, Mario; Cosottini, Mirco; Diciotti, Stefano; De Santis, Silvia; Passamonti, Luca; Tessa, Carlo; Toschi, Nicola; Giannelli, Marco

    2015-09-01

    The ability to image the whole brain through ever more subtle and specific methods/contrasts has come to play a key role in understanding the basis of brain abnormalities in several diseases. In magnetic resonance imaging (MRI), "diffusion" (i.e. the random, thermally-induced displacements of water molecules over time) represents an extraordinarily sensitive contrast mechanism, and the exquisite structural detail it affords has proven useful in a vast number of clinical as well as research applications. Since diffusion-MRI is a truly quantitative imaging technique, the indices it provides can serve as potential imaging biomarkers which could allow early detection of pathological alterations as well as tracking and possibly predicting subtle changes in follow-up examinations and clinical trials. Accordingly, diffusion-MRI has proven useful in obtaining information to better understand the microstructural changes and neurophysiological mechanisms underlying various neurodegenerative disorders. In this review article, we summarize and explore the main applications, findings, perspectives as well as challenges and future research of diffusion-MRI in various neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease and degenerative ataxias.

  1. MRI assessment of bone structure and microarchitecture.

    PubMed

    Chang, Gregory; Boone, Sean; Martel, Dimitri; Rajapakse, Chamith S; Hallyburton, Robert S; Valko, Mitch; Honig, Stephen; Regatte, Ravinder R

    2017-02-06

    Osteoporosis is a disease of weak bone and increased fracture risk caused by low bone mass and microarchitectural deterioration of bone tissue. The standard-of-care test used to diagnose osteoporosis, dual-energy x-ray absorptiometry (DXA) estimation of areal bone mineral density (BMD), has limitations as a tool to identify patients at risk for fracture and as a tool to monitor therapy response. Magnetic resonance imaging (MRI) assessment of bone structure and microarchitecture has been proposed as another method to assess bone quality and fracture risk in vivo. MRI is advantageous because it is noninvasive, does not require ionizing radiation, and can evaluate both cortical and trabecular bone. In this review article, we summarize and discuss research progress on MRI of bone structure and microarchitecture over the last decade, focusing on in vivo translational studies. Single-center, in vivo studies have provided some evidence for the added value of MRI as a biomarker of fracture risk or treatment response. Larger, prospective, multicenter studies are needed in the future to validate the results of these initial translational studies.

  2. In amnio MRI of mouse embryos.

    PubMed

    Roberts, Thomas A; Norris, Francesca C; Carnaghan, Helen; Savery, Dawn; Wells, Jack A; Siow, Bernard; Scambler, Peter J; Pierro, Agostino; De Coppi, Paolo; Eaton, Simon; Lythgoe, Mark F

    2014-01-01

    Mouse embryo imaging is conventionally carried out on ex vivo embryos excised from the amniotic sac, omitting vital structures and abnormalities external to the body. Here, we present an in amnio MR imaging methodology in which the mouse embryo is retained in the amniotic sac and demonstrate how important embryonic structures can be visualised in 3D with high spatial resolution (100 µm/px). To illustrate the utility of in amnio imaging, we subsequently apply the technique to examine abnormal mouse embryos with abdominal wall defects. Mouse embryos at E17.5 were imaged and compared, including three normal phenotype embryos, an abnormal embryo with a clear exomphalos defect, and one with a suspected gastroschisis phenotype. Embryos were excised from the mother ensuring the amnion remained intact and stereo microscopy was performed. Embryos were next embedded in agarose for 3D, high resolution MRI on a 9.4T scanner. Identification of the abnormal embryo phenotypes was not possible using stereo microscopy or conventional ex vivo MRI. Using in amnio MRI, we determined that the abnormal embryos had an exomphalos phenotype with varying severities. In amnio MRI is ideally suited to investigate the complex relationship between embryo and amnion, together with screening for other abnormalities located outside of the mouse embryo, providing a valuable complement to histology and existing imaging methods available to the phenotyping community.

  3. [MRI evaluation of cervicothoracic CSF hypotension].

    PubMed

    Maraval, A; Brugieres, P; Combes, C; Thomas, P; Blanc, R; Gaston, A

    2006-06-01

    We propose studying signs of cervicothoracic CSF hypotension by MRI. Axial T1-weighted GRE sequence with and without saturation bands positioned above and below the selected image plane, MR venography and MR Angiography with contrast administration are helpful to confirm the venous nature of the epidural thickening and to make the differential diagnosis with infectious or neoplastic epiduritis.

  4. Anatomical MRI with an atomic magnetometer.

    PubMed

    Savukov, I; Karaulanov, T

    2013-06-01

    Ultra-low field (ULF) MRI is a promising method for inexpensive medical imaging with various additional advantages over conventional instruments such as low weight, low power, portability, absence of artifacts from metals, and high contrast. Anatomical ULF MRI has been successfully implemented with SQUIDs, but SQUIDs have the drawback of a cryogen requirement. Atomic magnetometers have sensitivity comparable to SQUIDs and can be in principle used for ULF MRI to replace SQUIDs. Unfortunately some problems exist due to the sensitivity of atomic magnetometers to a magnetic field and gradients. At low frequency, noise is also substantial and a shielded room is needed for improving sensitivity. In this paper, we show that at 85 kHz, the atomic magnetometer can be used to obtain anatomical images. This is the first demonstration of any use of atomic magnetometers for anatomical MRI. The demonstrated resolution is 1.1 mm×1.4 mm in about 6 min of acquisition with SNR of 10. Some applications of the method are discussed. We discuss several measures to increase the sensitivity to reach a resolution 1 mm×1 mm.

  5. MRI findings in aphasic status epilepticus.

    PubMed

    Toledo, Manuel; Munuera, Josep; Sueiras, Maria; Rovira, Rosa; Alvarez-Sabín, José; Rovira, Alex

    2008-08-01

    Ictal-MRI studies including diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), and MR-angiography (MRA) in patients with aphasic status epilepticus (ASE) are lacking. In this report, we aim to describe the consequences of the ASE on DWIs and its impact on cerebral circulation. We retrospectively studied eight patients with ASE confirmed by ictal-EEG, who underwent ictal-MRI shortly after well-documented onset (mean time delay 3 h). ASE consisted in fluctuating aphasia, mostly associated with other subtle contralateral neurological signs such as hemiparesia, hemianopia, or slight clonic jerks. In MRI, six patients showed cortical temporoparietal hyperintensity in DWI and four of them had also ipsilateral pulvinar lesions. Five patients showed close spatial hyperperfusion areas matching the DWI lesions and an enhanced blow flow in the middle cerebral artery. Parenchymal lesions and hemodynamic abnormalities were not associated with seizure duration or severity in any case. The resolution of DWI lesions at follow-up MRI depended on the length of the MRIs interval. In patients with ASE, lesions on DWI in the temporo-parietal cortex and pulvinar nucleus combined with local hyperperfusion can be observed, even when they appear distant from the epileptic focus or the language areas.

  6. Toward MRI microimaging of single biological cells

    NASA Astrophysics Data System (ADS)

    Seeber, Derek Allan

    There is a great advantage in signal to noise ratio (SNR) that can be obtained in nuclear magnetic resonance (NMR) on very small samples (having spatial dimensions ˜100 mum or less) if one employs NMR "microcoils" that are of similarly small dimensions. These gains in SNR could enable magnetic resonance imaging (MRI) microscopy with spatial resolutions of ˜1--2 mum, much better than currently available. We report the design and testing of a NMR microcoil receiver apparatus, employing solenoidal microcoils of dimensions of tens to hundreds of microns, using an applied field of 9 Tesla (proton frequency 383 MHz). For the smallest receiver coils we attain sensitivity sufficient to observe proton NMR with SNR one in a single scan applied to ˜10 mum3 (10 fl) water sample, containing 7 x 1011 total proton spins. In addition to the NMR applications, microcoils have been applied to MRI producing images with spatial resolutions as low as 2 mum x 3.5 mum x 14.8 mum on phantom images of rods and beads. This resolution can be further improved. MRI imaging of small sample volumes requires significant hardware modifications and improvements, all of which are discussed. Specifically, MRI microscopy requires very strong (>10 T/m), rapidly switchable triaxial magnetic field gradients. We report the design and construction of such a triaxial gradient system, producing gradient substantially greater than 15 T/m in all three directions, x, y, and z (as high as 50 T/m for the x direction). The gradients are power by a custom designed power supply capable of providing currents in excess of 200 amps and switching times of less than 5 mus corresponding to slew rates of greater that 107 T/m/s. The gradients are adequately uniform (within 5% over a volume of 600 mum3) and sufficient for microcoil MRI of small samples.

  7. Efficient gradient calibration based on diffusion MRI

    PubMed Central

    Teh, Irvin; Maguire, Mahon L.

    2016-01-01

    Purpose To propose a method for calibrating gradient systems and correcting gradient nonlinearities based on diffusion MRI measurements. Methods The gradient scaling in x, y, and z were first offset by up to 5% from precalibrated values to simulate a poorly calibrated system. Diffusion MRI data were acquired in a phantom filled with cyclooctane, and corrections for gradient scaling errors and nonlinearity were determined. The calibration was assessed with diffusion tensor imaging and independently validated with high resolution anatomical MRI of a second structured phantom. Results The errors in apparent diffusion coefficients along orthogonal axes ranged from −9.2% ± 0.4% to + 8.8% ± 0.7% before calibration and −0.5% ± 0.4% to + 0.8% ± 0.3% after calibration. Concurrently, fractional anisotropy decreased from 0.14 ± 0.03 to 0.03 ± 0.01. Errors in geometric measurements in x, y and z ranged from −5.5% to + 4.5% precalibration and were likewise reduced to −0.97% to + 0.23% postcalibration. Image distortions from gradient nonlinearity were markedly reduced. Conclusion Periodic gradient calibration is an integral part of quality assurance in MRI. The proposed approach is both accurate and efficient, can be setup with readily available materials, and improves accuracy in both anatomical and diffusion MRI to within ±1%. Magn Reson Med 77:170–179, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. PMID:26749277

  8. The Effects of Phosphatidylserine and Omega-3 Fatty Acid-Containing Supplement on Late Life Depression

    PubMed Central

    Komori, Teruhisa

    2015-01-01

    Late life depression is often associated with a poor response to antidepressants; therefore an alternative strategy for therapy is required. Although several studies have reported that phosphatidylserine (PS) may be effective for late life depression and that omega-3 fatty acids DHA and EPA have also proven beneficial for many higher mental functions, including depression, no concrete conclusion has been reached. This study was performed to clarify the effect of PS and omega-3 fatty acid-containing supplement for late life depression by not only clinical evaluation but also salivary cortisol levels. Eighteen elderly subjects with major depression were selected for the study. In all, insufficient improvement had been obtained by antidepressant therapy for at least 6 months. The exclusion criteria from prior brain magnetic resonance images (MRI) included the presence of structural MRI findings compatible with stroke or other gross brain lesions or malformations, but not white matter hypersensitivities. They took a supplement containing PS 100 mg, DHA 119 mg and EPA 70 mg three times a day for 12 weeks. The effects of the supplement were assessed using the 17-item Hamilton depression scale (HAM-D17) and the basal levels and circadian rhythm of salivary cortisol. The study adopted them as indices because: salivary cortisol levels are high in patients with depression, their circadian rhythm related to salivary cortisol is often irregular, and these symptoms are alleviated as depression improves. The mean HAM-D17 in all subjects taking the supplement was significantly improved after 12 weeks of taking the supplement. These subjects were divided into 10 non-responders and 8 responders. The basal levels and circadian rhythm of salivary cortisol were normalized in the responders while not in non-responders. PS and omega-3 fatty acids, or other elements of the supplement, may be effective for late life depression, associated with the correction of basal levels and circadian

  9. Late Glacial and Late Holocene Paleohydrology of Central Asia

    NASA Astrophysics Data System (ADS)

    Aichner, B.; Feakins, S. J.; Mischke, S.; Herzschuh, U.; Liu, X.; Rajabov, I.; Wang, Y.; Heinecke, L.

    2013-12-01

    The goal of this study is to deepen the understanding of past climatological, ecological and hydrological changes in Central Asia, by means of organic geochemical proxies and in close cooperation with other work groups providing biological and sedimentological data. We analysed an 8 m sediment core from Lake Karakuli, a small open freshwater lake situated at an altitude of 3,657 m between the massifs of Muztagh Ata (7,546 m) and Kongur Shan (7,719 m) in western China. Additional work is in progress on a 12 m core derived from Lake Karakul in Tajikistan, a large closed saline lake situated in a tectonic graben structure at an altitude of 3,928 m. The distance between the two lakes is 130 km and basal ages of the cores are ca. 4.7 ka BP (China) and ca. 27 ka BP (Tajikistan). The lake catchments may be classified as alpine steppe to alpine deserts with mean annual temperature of ca. 0 °C and mean annual precipitation of ca. 100 mm, respectively. Summer precipitation, associated with the Indian monsoon, accounts for <30% of the annual total, whereas most precipitation is supplied by mid-latitude Westerlies between March and May. In the small Chinese lake long-chain fatty acids (FAs) were mainly attributed to terrestrial sources by compound-specific carbon isotopic analyses. In contrast δ13C values up to -14‰ for abundant mid-chain FAs suggest aquatic origins in the large Lake Karakul. Hydrogen isotopic variability is ca. 15‰ in the mid-Holocene record and ca. 60‰ in the first data derived from the Late Glacial record. In the latter, the most pronounced change from higher to lower δD-values of aquatic biomarkers is tentatively interpreted as change from arid to more humid conditions at the Late Glacial to Holocene transition. Since in Central Asia isotopic variability of precipitation mainly correlates with temperature, we interpret high resolution δD data of terrestrial long-chain FAs in the younger core to mainly reflect mid-Holocene temperature variations

  10. MRI simulation: end-to-end testing for prostate radiation therapy using geometric pelvic MRI phantoms

    NASA Astrophysics Data System (ADS)

    Sun, Jidi; Dowling, Jason; Pichler, Peter; Menk, Fred; Rivest-Henault, David; Lambert, Jonathan; Parker, Joel; Arm, Jameen; Best, Leah; Martin, Jarad; Denham, James W.; Greer, Peter B.

    2015-04-01

    To clinically implement MRI simulation or MRI-alone treatment planning requires comprehensive end-to-end testing to ensure an accurate process. The purpose of this study was to design and build a geometric phantom simulating a human male pelvis that is suitable for both CT and MRI scanning and use it to test geometric and dosimetric aspects of MRI simulation including treatment planning and digitally reconstructed radiograph (DRR) generation. A liquid filled pelvic shaped phantom with simulated pelvic organs was scanned in a 3T MRI simulator with dedicated radiotherapy couch-top, laser bridge and pelvic coil mounts. A second phantom with the same external shape but with an internal distortion grid was used to quantify the distortion of the MR image. Both phantoms were also CT scanned as the gold-standard for both geometry and dosimetry. Deformable image registration was used to quantify the MR distortion. Dose comparison was made using a seven-field IMRT plan developed on the CT scan with the fluences copied to the MR image and recalculated using bulk electron densities. Without correction the maximum distortion of the MR compared with the CT scan was 7.5 mm across the pelvis, while this was reduced to 2.6 and 1.7 mm by the vendor’s 2D and 3D correction algorithms, respectively. Within the locations of the internal organs of interest, the distortion was <1.5 and <1 mm with 2D and 3D correction algorithms, respectively. The dose at the prostate isocentre calculated on CT and MRI images differed by 0.01% (1.1 cGy). Positioning shifts were within 1 mm when setup was performed using MRI generated DRRs compared to setup using CT DRRs. The MRI pelvic phantom allows end-to-end testing of the MRI simulation workflow with comparison to the gold-standard CT based process. MRI simulation was found to be geometrically accurate with organ dimensions, dose distributions and DRR based setup within acceptable limits compared to CT.

  11. Central nervous system MRI and cardiac implantable electronic devices.

    PubMed

    Cadieu, Romain; Peron, Marilyne; Le Ven, Florent; Kerdraon, Sébastien; Boutet, Claire; Mansourati, Jacques; Ben Salem, Douraied

    2017-02-01

    As the population ages and indications for MRI increase, it is estimated that 50 to 75% of patients with a cardiac implantable electronic device (CIED) - pacemaker (PM) or implanted cardiac defibrillator (ICD) - will need an MRI during their CIED's lifetime. Three categories of materials are defined: MRI compatible, MRI non-compatible, and MRI conditional. MRI compatible CIEDs without electrodes have been developed, but do not allow battery changes, so that they are exclusively indicated for patients whose life expectancy is less than that of the battery (6-7years). For MRI conditional CIEDs, all manufacturers publish restrictions. These restrictions can relate to the patient (size, position in the MRI, body temperature), the MRI parameters (magnetic field), or the examination in itself (gradients, specific absorption rate, duration, isocenter). The neuroradiologist can expect to be confronted with the issue of MRI in patients with a CIED. The purpose of this review is to provide them with updated information on MRI and CIEDs.

  12. Skeletal Muscle Magnetic Resonance Imaging of the Lower Limbs in Late-onset Lipid Storage Myopathy with Electron Transfer Flavoprotein Dehydrogenase Gene Mutations

    PubMed Central

    Liu, Xin-Yi; Jin, Ming; Wang, Zhi-Qiang; Wang, Dan-Ni; He, Jun-Jie; Lin, Min-Ting; Fu, Hong-Xia; Wang, Ning

    2016-01-01

    Background: Lipid storage myopathy (LSM) is a genetically heterogeneous group with variable clinical phenotypes. Late-onset multiple acyl-coenzyme A dehydrogenation deficiency (MADD) is a rather common form of LSM in China. Diagnosis and clinical management of it remain challenging, especially without robust muscle biopsy result and genetic detection. As the noninvasion and convenience, muscle magnetic resonance imaging (MRI) is a helpful assistant, diagnostic tool for neuromuscular disorders. However, the disease-specific MRI patterns of muscle involved and its diagnostic value in late-onset MADD have not been systematic analyzed. Methods: We assessed the MRI pattern and fat infiltration degree of the lower limb muscles in 28 late-onset MADD patients, combined with detailed clinical features and gene spectrum. Fat infiltration degree of the thigh muscle was scored while that of gluteus was described as obvious or not. Associated muscular atrophy was defined as obvious muscle bulk reduction. Results: The mean scores were significantly different among the anterior, medial, and posterior thigh muscle groups. The mean of fat infiltration scores on posterior thigh muscle group was significantly higher than either anterior or medial thigh muscle group (P < 0.001). Moreover, the mean score on medial thigh muscle group was significantly higher than that of anterior thigh muscle group (P < 0.01). About half of the patients displayed fat infiltration and atrophy in gluteus muscles. Of 28 patients, 12 exhibited atrophy in medial and/or posterior thigh muscle groups, especially in posterior thigh muscle group. Muscle edema pattern was not found in all the patients. Conclusions: Late-onset MADD patients show a typical muscular imaging pattern of fat infiltration and atrophy on anterior, posterior, and medial thigh muscle groups, with major involvement of posterior thigh muscle group and gluteus muscles and a sparing involvement of anterior thigh compartment. Our findings also

  13. PET/MRI: A luxury or a necessity?

    PubMed

    Carreras-Delgado, J L; Pérez-Dueñas, V; Riola-Parada, C; García-Cañamaque, L

    2016-01-01

    PET/MRI is a new multimodality technique with a promising future in diagnostic imaging. Technical limitations are being overcome. Interference between the two systems (PET and MRI) seems to have been resolved. MRI-based PET attenuation correction can be performed safely. Scan time is acceptable and the study is tolerable, with claustrophobia prevalence similar to that of MRI. Quantification with common parameters, such as Standardized Uptake Value (SUV), shows a fairly good correlation between both systems. However, PET/CT currently provides better results in scan time, scan costs, and patient comfort. Less patient radiation exposure is a big advantage of PET/MRI over PET/CT, which makes it particularly recommended in paediatric and adolescent patients requiring one or more studies. PET/MRI indications are the same as those of PET/CT, given that in cases where MRI is superior to CT, PET/MRI is superior to PET/CT. This superiority is clear in many soft tissue tumours. Moreover, it is common to perform both PET/CT and MRI in neurological diseases, as well as in some tumours, such as breast cancer. A single PET/MRI study replaces both with obvious benefit. MRI also allows other MRI-based PET corrections, such as motion or partial volume effect corrections. The better spatial resolution of MRI allows the transfer of well-defined MRI areas or small volumes of interest to PET image, in order to measure PET biomarkers in these areas. The richness of information of both techniques opens up immense possibilities of synergistic correlation between them.

  14. Intra-Hepatic Spillage of Gallstones as a Late Complication of Laparoscopic Cholecystectomy: MR Imaging Findings

    PubMed Central

    Ragozzino, Alfonso; Puglia, Marta; Romano, Federica; Imbriaco, Massimo

    2016-01-01

    Summary Background Spillage of gallstones in the abdominal cavity may rarely occur during the course of laparoscopic cholecystectomy. Dropped gallstones in the peritoneal and extra-peritoneal cavity are usually asymptomatic. However, they may lead to abscess formation with an estimated incidence of about 0.3%. Common locations of the abscess are in the abdominal wall followed by the intra-abdominal cavity, usually in the sub-hepatic or retro-peritoneum inferior to the sub-hepatic space. Case Report We hereby describe an unusual case of infected spilled gallstones in the right sub-phrenic space, prospectively detected on abdominal MRI performed two years after laparoscopic cholecystectomy, in a patient with only a mild right-sided abdominal complaint. Conclusions This case highlights the role of MRI in suggesting the right diagnosis in cases with vague or even absent symptomatology. In our case the patient’s history together with high quality abdomen MRI allowed the correct diagnosis. Radiologists should be aware of this rare and late onset complication, even after many years from surgery as an incidental finding in almost asymptomatic patients. PMID:27471576

  15. Total-Body Irradiation Produces Late Degenerative Joint Damage in Rats

    PubMed Central

    Hutchinson, Ian D.; Olson, John; Lindburg, Carl A.; Payne, Valerie; Collins, Boyce; Smith, Thomas L.; Munley, Michael T.; Wheeler, Kenneth T.; Willey, Jeffrey S.

    2014-01-01

    Purpose Premature musculoskeletal joint failure is a major source of morbidity among childhood cancer survivors. Radiation effects on synovial joint tissues of the skeleton are poorly understood. Our goal was to assess long-term changes in the knee joint from skeletally mature rats that received total-body irradiation while skeletal growth was ongoing. Materials and Methods 14 week-old rats were irradiated with 1, 3 or 7 Gy total-body doses of 18 MV x-rays. At 53 weeks of age, structural and compositional changes in knee joint tissues (articular cartilage, subchondral bone, and trabecular bone) were characterized using 7T MRI, nanocomputed tomography (nanoCT), microcomputed tomography (microCT), and histology. Results T2 relaxation times of the articular cartilage were lower after exposure to all doses. Likewise, calcifications were observed in the articular cartilage. Trabecular bone microarchitecture was compromised in the tibial metaphysis at 7 Gy. Mild to moderate cartilage erosion was scored in the 3 and 7 Gy rats. Conclusions Late degenerative changes in articular cartilage and bone were observed after total body irradiation in adult rats exposed prior to skeletal maturity. 7T MRI, microCT, nanoCT, and histology identified potential prognostic indicators of late radiation-induced joint damage. PMID:24885745

  16. Isolated Unilateral Tongue Atrophy: A Possible Late Complication of Juxta Cephalic Radiation Therapy.

    PubMed

    Alqahtani, Saeed A; Agha, Caroline; Rothstein, Ted

    2016-07-26

    BACKGROUND Isolated unilateral hypoglossal nerve injury is extremely rare. It may be caused by radiation therapy targeting neoplasms of the cephalic region. CASE REPORT A 51-year-old man with synovial sarcoma of the left upper arm status post extensive radiation therapy in 1980 presented in late 2014 with gradual onset of speech difficulty and difficulty moving his tongue for a couple of weeks. Neurological examination revealed isolated left-sided unilateral tongue atrophy. Postradiation residual extensive cicatrix with erythema over the whole left upper extremity extending to the neck on the affected side was noticed. On head magnetic resonance imaging (MRI) before and after administration of gadolinium, he was found to have asymmetrically fatty striations, atrophy, and fibrosis in the left tongue consistent with radiation toxicity. The patient's tongue weakness persisted without improvement. CONCLUSIONS The diagnosis of unilateral hypoglossal nerve injury is usually difficult. Detailed neurological examinations and thorough investigations including head MRI are very helpful. Previous exposure to radiation therapy is a potential cause of hypoglossal nerve injury. To our knowledge, this is the first case report that presents isolated unilateral tongue atrophy as a late complication of juxta cephalic radiation therapy.

  17. Isolated Unilateral Tongue Atrophy: A Possible Late Complication of Juxta Cephalic Radiation Therapy

    PubMed Central

    Alqahtani, Saeed A.; Agha, Caroline; Rothstein, Ted

    2016-01-01

    Patient: Male, 51 Final Diagnosis: Radiation therapy induced unilateral tongue atrophy Symptoms: — Medication: — Clinical Procedure: EMG Specialty: Neurology Objective: Rare disease Background: Isolated unilateral hypoglossal nerve injury is extremely rare. It may be caused by radiation therapy targeting neoplasms of the cephalic region. Case Report: A 51-year-old man with synovial sarcoma of the left upper arm status post extensive radiation therapy in 1980 presented in late 2014 with gradual onset of speech difficulty and difficulty moving his tongue for a couple of weeks. Neurological examination revealed isolated left-sided unilateral tongue atrophy. Postradiation residual extensive cicatrix with erythema over the whole left upper extremity extending to the neck on the affected side was noticed. On head magnetic resonance imaging (MRI) before and after administration of gadolinium, he was found to have asymmetrically fatty striations, atrophy, and fibrosis in the left tongue consistent with radiation toxicity. The patient’s tongue weakness persisted without improvement. Conclusions: The diagnosis of unilateral hypoglossal nerve injury is usually difficult. Detailed neurological examinations and thorough investigations including head MRI are very helpful. Previous exposure to radiation therapy is a potential cause of hypoglossal nerve injury. To our knowledge, this is the first case report that presents isolated unilateral tongue atrophy as a late complication of juxta cephalic radiation therapy. PMID:27458010

  18. MRI-guided laser interstitial thermal therapy in neuro-oncology: a review of its current clinical applications.

    PubMed

    Rahmathulla, Gazanfar; Recinos, Pablo F; Kamian, Kambiz; Mohammadi, Alireza M; Ahluwalia, Manmeet S; Barnett, Gene H

    2014-01-01

    Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) is a minimally invasive treatment modality with recent increasing use to ablate brain tumors. When originally introduced in the late 1980s, the inability to precisely monitor and control the thermal ablation limited the adoption of LITT in neuro-oncology. Popularized as a means of destroying malignant hepatic and renal metastatic lesions percutaneously, its selective thermal tumor destruction and preservation of adjacent normal tissues have since been optimized for use in neuro-oncology. The progress made in real-time thermal imaging with MRI, laser probe design, and computer algorithms predictive of tissue kill has led to the resurgence of interest in LITT as a means to ablate brain tumors. Current LITT systems offer a surgical option for some inoperable brain tumors. We discuss the origins, principles, current indications, and future directions of MRI-guided LITT in neuro-oncology.

  19. [fMRI study of deliberate deception].

    PubMed

    Kireev, M V; Korotkov, A D; Medvedev, C V

    2012-01-01

    The aim of the present research was to study the deliberate deception. Event related functional magnetic resonance (fMRI) imaging technique was used to assess the changes in functional brain activity by virtue of recording blood oxygen level dependant signal (BOLD-signal). 12 right-handed healthy volunteers aged 19-44 participated in the study. BOLD images were acquired in three different experimental trials. There were deliberate deception, manipulative honest and control truthful trials (catch trials). The main finding of the present study is that the deliberate deception and manipulative honest actions in comparison with instructed truthful responding was characterized by BOLD signal increase within the anterior cingulated cortex (ACC), frontal and parietal areas as well. Comparison of present fMRI data with results demonstrated in our previous research implemented with event related potentials technique points to the involvement of the brain mechanism of error detection to brain processing of deliberate deception.

  20. [CT and MRI of hip arthroplasty].

    PubMed

    Agten, C A; Sutter, R; Pfirrmann, C W A

    2014-07-01

    Metal-induced artifacts impair image quality of computed tomography (CT) and magnetic resonance imaging (MRI) in patients with hip prostheses. Due to new developments in metal artifact reduction both methods can now be used for evaluation of a painful hip prosthesis. Iterative reconstruction algorithms and dual-energy scans are among the newer CT techniques for artifact reduction, while slice-encoding for metal artifact correction (SEMAC) and multi-acquisition variable-resonance image combination (MAVRIC) have introduced substantial improvements for MRI. Loosening of the hip prosthesis, osteolysis from small wear particles and pseudotumors in metal-on-metal prostheses are specific pathologies in patients with total hip arthroplasty. Other causes of painful hip prostheses are infections, fractures, tendinopathies, tendon ruptures, muscle and nerve alterations and heterotopic ossifications.

  1. Scurvy in an autistic child: MRI findings.

    PubMed

    Gongidi, Preetam; Johnson, Craig; Dinan, David

    2013-10-01

    Scurvy results from a deficiency of vitamin C and is rarely seen in the United States. We describe the MRI findings of a case of scurvy in an autistic child with food-avoidant behavior. Advanced imaging is rarely performed in clinically well-understood disease entities such as scurvy. Typical radiographic findings are well described leading to definitive diagnosis, although the findings can be missed or misinterpreted given the rarity of scurvy in daily practice. To our knowledge, MRI features of scurvy in children in the US have been described in only one case report. This case of scurvy in an autistic child with food-avoidant behavior emphasizes that classic nutritional deficiencies, despite their rarity, must be included in the differential diagnosis of at-risk populations.

  2. Optical textile tests MRI patients from afar

    NASA Astrophysics Data System (ADS)

    Gould, Paula

    2008-11-01

    Researchers in Europe have developed a wearable textile fitted with optical sensors that could be used to remotely monitor a patient's breathing patterns while they undergo magnetic resonance imaging (MRI) scans. The new textile will allow medical staff to keep an eye on children and other vulnerable patients who often have to be calmed with sedatives or anaesthetic drugs to keep them still during a scan. The technique will be particularly useful if proposed European Union (EU) legislation that is designed to protect medical staff from being exposed to the high magnetic fields of MRI systems comes into force in 2012. The new rules would prevent nurses from being in the room where the scan is taking place.

  3. Computational approaches to fMRI analysis.

    PubMed

    Cohen, Jonathan D; Daw, Nathaniel; Engelhardt, Barbara; Hasson, Uri; Li, Kai; Niv, Yael; Norman, Kenneth A; Pillow, Jonathan; Ramadge, Peter J; Turk-Browne, Nicholas B; Willke, Theodore L

    2017-02-23

    Analysis methods in cognitive neuroscience have not always matched the richness of fMRI data. Early methods focused on estimating neural activity within individual voxels or regions, averaged over trials or blocks and modeled separately in each participant. This approach mostly neglected the distributed nature of neural representations over voxels, the continuous dynamics of neural activity during tasks, the statistical benefits of performing joint inference over multiple participants and the value of using predictive models to constrain analysis. Several recent exploratory and theory-driven methods have begun to pursue these opportunities. These methods highlight the importance of computational techniques in fMRI analysis, especially machine learning, algorithmic optimization and parallel computing. Adoption of these techniques is enabling a new generation of experiments and analyses that could transform our understanding of some of the most complex-and distinctly human-signals in the brain: acts of cognition such as thoughts, intentions and memories.

  4. Acupressure magnets: a possible MRI hazard.

    PubMed

    Otjen, Jeffrey P; Mallon, Kara; Brown, Julie C

    2015-03-01

    The use of magnets as a component of complementary and alternative medicine is increasingly common. Magnet therapy is used to treat a variety of conditions and often involves tiny magnets adhered to the skin. In auriculotherapy, magnets are placed in specific locations of the ear pinnae which represent particular parts of the body. While generally considered safe, these magnets have the potential to cause imaging problems and serious injury during MRI. We report a case of auriculotherapy magnets which escaped detection despite the use of screening forms and a walk-through metal detector. The magnets caused image artifact but no other patient harm. We recommend updating patient screening practices and educating providers placing therapeutic magnets and performing MRIs of this new potential MRI hazard.

  5. UTE MRI of the Osteochondral Junction

    PubMed Central

    Biswas, Reni; Chen, Karen; Chang, Eric Y.; Chung, Christine B.

    2014-01-01

    The osteochondral junction is composed of numerous tissue components and serves important functions relating to structural stability and proper nutrition in joints such as the knee and spine. Conventional MR techniques have been inadequate at imaging the tissues of the osteochondral junction primarily because of the intrinsically short T2 nature of these tissues, rendering them “invisible” with the standard acquisitions. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal of osteochondral tissues, thereby allowing direct evaluation. This article reviews the anatomy of the osteochondral junction of the knee and the spine, technical aspects of UTE MRI, and the application of UTE MRI for evaluation of the osteochondral junction. PMID:25061547

  6. Automatic cardiac MRI myocardium segmentation using graphcut

    NASA Astrophysics Data System (ADS)

    Kedenburg, Gunnar; Cocosco, Chris A.; Köthe, Ullrich; Niessen, Wiro J.; Vonken, Evert-jan P. A.; Viergever, Max A.

    2006-03-01

    Segmentation of the left myocardium in four-dimensional (space-time) cardiac MRI data sets is a prerequisite of many diagnostic tasks. We propose a fully automatic method based on global minimization of an energy functional by means of the graphcut algorithm. Starting from automatically obtained segmentations of the left and right ventricles and a cardiac region of interest, a spatial model is constructed using simple and plausible assumptions. This model is used to learn the appearance of different tissue types by non parametric robust estimation. Our method does not require previously trained shape or appearance models. Processing takes 30-40s on current hardware. We evaluated our method on 11 clinical cardiac MRI data sets acquired using cine balanced fast field echo. Linear regression of the automatically segmented myocardium volume against manual segmentations (performed by a radiologist) showed an RMS error of about 12ml.

  7. Brain MRI findings in Wernicke encephalopathy.

    PubMed

    Wicklund, Meredith R; Knopman, David S

    2013-08-01

    A 71-year-old woman with myelofibrosis on chemotherapy experienced an acute illness with nausea, vomiting, and diarrhea. Two weeks later, she developed an acute confusional state characterized by disorientation and fluctuating alertness with normal speech and language. Her neurologic examination demonstrated an upper motor neuron pattern of right hemiparesis. She reported double vision though ophthalmoparesis was not appreciated. Her gait was normal. While hospitalized, she developed generalized tonic-clonic seizures. Brain MRI revealed a small area of restricted diffusion of the left precentral gyrus (figure). She was diagnosed with a stroke with secondary seizures; however, as the confusional state resolved, she developed profound retrograde and anterograde amnesia. Review of the brain MRI showed high T2 signal in the medial thalamus and contrast enhancement of the mamillary bodies; a diagnosis of Wernicke-Korsakoff syndrome was entertained and she was started on thiamine replacement. The encephalopathy and hemiparesis resolved though she remains severely amnestic.

  8. Impact of low signal intensity assessed by cine magnetic resonance imaging on detection of poorly viable myocardium in patients with prior myocardial infarction.

    PubMed

    Ota, Shingo; Tanimoto, Takashi; Orii, Makoto; Hirata, Kumiko; Shiono, Yasutsugu; Shimamura, Kunihiro; Matsuo, Yoshiki; Yamano, Takashi; Ino, Yasushi; Kitabata, Hironori; Yamaguchi, Tomoyuki; Kubo, Takashi; Tanaka, Atsushi; Imanishi, Toshio; Akasaka, Takashi

    2015-05-13

    Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) has been established as a modality to detect myocardial infarction (MI). However, the use of gadolinium contrast is limited in patients with advanced renal dysfunction. Although the signal intensity (SI) of infarct area assessed by cine MRI is low in some patients with prior MI, the prevalence and clinical significance of low SI has not been evaluated. The aim of this study was to evaluate how low SI assessed by cine MRI may relate to the myocardial viability in patients with prior MI. Fifty patients with prior MI underwent both cine MRI and LGE-MRI. The left ventricle was divided into 17 segments. The presence of low SI and the wall motion score (WMS) of each segment were assessed by cine MRI. The transmural extent of infarction was evaluated by LGE-MRI. LGE was detected in 329 of all 850 segments (39%). The low SI assessed by cine MRI was detected in 105 of 329 segments with LGE (32%). All segments with low SI had LGE. Of all 329 segments with LGE, the segments with low SI showed greater transmural extent of infarction (78 [72 - 84] % versus 53 [38 - 72] %, P < 0.01), thinner wall (4.0[3.1 - 4.8] mm versus 6.5 [5.2 - 8.1] mm, P < 0.01), and higher WMS (4.0 [4.0 - 4.0] versus 2.0 [2.0 - 3.0], P < 0.01). The low SI assessed by cine MRI may be effective for detecting poorly viable myocardium in patients with prior MI.

  9. Robotic Prostate Biopsy in Closed MRI Scanner

    DTIC Science & Technology

    2009-02-01

    and robot control. The functions of the device will be tested in phantom studies at the Brigham and Women’s Hospital.  Demonstrated integrated...system in 3T MRI at the Brigham and Women’s Hospital. See Reference [3].  Demonstrated needle placement in phantoms under real-time MR image guidance...workflow has been evaluated in phantom studies with accurate visualization and targeting of five out of five 1 cm targets. The paper explains the

  10. Echocardiography as a Screening Test for Myocardial Scarring in Children with Hypertrophic Cardiomyopathy

    PubMed Central

    Nield, Lynne; Dragulescu, Andreea; Benson, Lee

    2016-01-01

    Introduction. Hypertrophic cardiomyopathy (HCM) is burdened with morbidity and mortality including tachyarrhythmias and sudden cardiac death. These complications are attributed in part to the formation of proarrhythmic scars in the myocardium. The presence of extensive LGE is a risk factor for adverse outcomes in HCM. Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (cMRI) is the standard for the noninvasive evaluation of myocardial scars. However, echocardiography represents an attractive screening tool for myocardial scarring. The aim of this study was to compare the suitability of echocardiography to detect myocardial scars to the standard of cMRI-LGE. Methods. The cMRI studies and echocardiograms from 56 consecutive children with HCM were independently evaluated for the presence of cMRI-LGE and echocardiographic evidence of scarring by expert readers. Results. Echocardiography had a high sensitivity (93%) and negative predictive value (94%) in comparison to LGE. The false positive rate was high, leading to a low specificity (37%) and a low positive predictive value (35%). Conclusions. Given the poor specificity and positive predictive value, echocardiography is not a suitable screening test for the presence of myocardial scarring in children with HCM. However, children without echocardiographic evidence of myocardial scarring may not need to undergo cardiac magnetic resonance imaging to “rule in” LGE. PMID:27974896

  11. Early and late abortion methods.

    PubMed

    van Lith, D A; Wittman, R; Keith, L G

    1984-12-01

    This chapter provides a detailed description of 1st and 2nd trimester abortion techniques. In general, low morbidity is facilitated by preoperative diagnosis and evaluation, operator skill, sterile technique, avoidance of trauma, completeness of evacuation, and postoperative care. The 1st trimester technique used by the authors involves predilatation with laminaria, paracervical and intracervical blocks (anesthetic solution, 1% lignocaine with adrenaline), dilatation with either the Hawkin Ambler type or half-sized Pratt dilator, and evacuation with the van Lith or Karman type suction cannula. For 2nd trimester pregnancy termination, the authors use aspirotomy, a technique that combines the classic dilatation and evacuation method with suction curettage. An ergometrine maleate preparation is administered at the start of the procedure to produce sustained contraction of the uterine wall, decrease the chance of perforation, and accelerate the emptying process. Adrenaline in 1% lignocaine is used as a local anesthetic solution. A specially designed crushing forceps decreases the cervical dilatation required. Also presented is a technique for late 2nd trimester (16-20 weeks gestation) abortion that involves prostaglandins or the Finks dilatation and evacuation technique. The complication rate in the authors' unit for 3500 2nd trimester terminations was less than 0.5% but rose after 17 weeks of gestation.

  12. Very late relapse of medulloblastoma.

    PubMed

    Cieślak, Ewa; Kepka, Lucyna; Fijuth, Jacek; Marchel, Andrzej; Kroh, Halina

    2004-01-01

    A case of 47-year-old woman with a local relapse of medulloblastoma 23 years after initial presentation is reported. At the age of 24, the patient underwent resection of medulloblastoma of the right cerebellar lobe, followed by the craniospinal orthovoltage irradiation (3600 R to the brain, and 3000 R to the spinal cord). At the 21st year of follow-up, a second cancer originating in the thyroid gland was diagnosed. Thyroidectomy followed by 131-iodotherapy for the papillary cancer was performed. Two years later she was operated for the recurrence of medulloblastoma at the former site. The patient was unfit for chemotherapy due to poor bone marrow reserve following the previous treatment. The reirradiation of the posterior cranial fossa was performed postoperatively. The patient was given 45 Gy in 25 fractions to the recurred tumour volume with 2 cm margin within 41 days. The treatment was performed by 6 MV photons with conformal technique and noncoplanar beams arrangement. The patient is disease free 15 months after relapse of medulloblastoma. The following problems are discussed: late relapse of medulloblastoma, secondary cancers after craniospinal irradiation, and retreatment of CNS tumours.

  13. Measuring glomerular number from kidney MRI images

    NASA Astrophysics Data System (ADS)

    Thiagarajan, Jayaraman J.; Natesan Ramamurthy, Karthikeyan; Kanberoglu, Berkay; Frakes, David; Bennett, Kevin; Spanias, Andreas

    2016-03-01

    Measuring the glomerular number in the entire, intact kidney using non-destructive techniques is of immense importance in studying several renal and systemic diseases. Commonly used approaches either require destruction of the entire kidney or perform extrapolation from measurements obtained from a few isolated sections. A recent magnetic resonance imaging (MRI) method, based on the injection of a contrast agent (cationic ferritin), has been used to effectively identify glomerular regions in the kidney. In this work, we propose a robust, accurate, and low-complexity method for estimating the number of glomeruli from such kidney MRI images. The proposed technique has a training phase and a low-complexity testing phase. In the training phase, organ segmentation is performed on a few expert-marked training images, and glomerular and non-glomerular image patches are extracted. Using non-local sparse coding to compute similarity and dissimilarity graphs between the patches, the subspace in which the glomerular regions can be discriminated from the rest are estimated. For novel test images, the image patches extracted after pre-processing are embedded using the discriminative subspace projections. The testing phase is of low computational complexity since it involves only matrix multiplications, clustering, and simple morphological operations. Preliminary results with MRI data obtained from five kidneys of rats show that the proposed non-invasive, low-complexity approach performs comparably to conventional approaches such as acid maceration and stereology.

  14. Evolving role of MRI in Crohn's disease.

    PubMed

    Yacoub, Joseph H; Obara, Piotr; Oto, Aytekin

    2013-06-01

    MR enterography is playing an evolving role in the evaluation of small bowel Crohn's disease (CD). Standard MR enterography includes a combination of rapidly acquired T2 sequence, balanced steady-state acquisition, and contrast enhanced T1-weighted gradient echo sequence. The diagnostic performance of these sequences has been shown to be comparable, and in some respects superior, to other small bowel imaging modalities. The findings of CD on MR enterography have been well described in the literature. New and emerging techniques such as diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), cinematography, and magnetization transfer, may lead to improved accuracy in characterizing the disease. These advanced techniques can provide quantitative parameters that may prove to be useful in assessing disease activity, severity, and response to treatment. In the future, MR enterography may play an increasing role in management decisions for patients with small bowel CD; however, larger studies are needed to validate these emerging MRI parameters as imaging biomarkers.

  15. Quantitative fMRI and oxidative neuroenergetics

    PubMed Central

    Hyder, Fahmeed; Rothman, Douglas L.

    2012-01-01

    The discovery of functional magnetic resonance imaging (fMRI) has greatly impacted neuroscience. The blood oxygenation level-dependent (BOLD) signal, using deoxyhemoglobin as an endogenous paramagnetic contrast agent, exposes regions of interest in task-based and resting-state paradigms. However the BOLD contrast is at best a partial measure of neuronal activity, because the functional maps obtained by differencing or correlations ignore the total neuronal activity in the baseline state. Here we describe how studies of brain energy metabolism at Yale, especially with 13C magnetic resonance spectroscopy and related techniques, contributed to development of quantitative functional brain imaging with fMRI by providing a reliable measurement of baseline energy. This narrative takes us on a journey, from molecules to mind, with illuminating insights about neuronal-glial activities in relation to energy demand of synaptic activity. These results, along with key contributions from laboratories worldwide, comprise the energetic basis for quantitative interpretation of fMRI data. PMID:22542993

  16. [Differential diagnosis of parkinsonian syndromes using MRI].

    PubMed

    Mahlknecht, P; Schocke, M; Seppi, K

    2010-10-01

    The differential diagnosis of parkinsonian syndromes is considered one of the most challenging in clinical neurology. Despite published consensus operational criteria for the diagnosis of Parkinson's disease (PD) and the various atypical parkinsonian disorders (APD), such as progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and corticobasal degeneration (CBD), the clinical separation of APDs from PD carries a high rate of misdiagnosis. However, the early differentiation between APD and PD, each characterized by a very different natural history, is crucial for determining the prognosis and choosing a treatment strategy. Despite limitations the various modern magnetic resonance imaging (MRI) techniques have undoubtedly added to the differential diagnosis of neurodegenerative parkinsonism. In clinical practice conventional MRI with visual assessment of T2 and T1-weighted imaging is a well established method for the exclusion of symptomatic parkinsonism due to other pathologies and may also point to the diagnosis of APD. Furthermore, advances in MRI techniques, such as diffusion-weighted imaging (DWI), have enabled abnormalities in the basal ganglia and infratentorial brain structures in APD to be quantitatively illustrated.

  17. Unusual MRI Findings in a Polio Survivor

    PubMed Central

    Kubosawa, Hitoshi; Ishii, Takeshi

    2016-01-01

    A 63-year-old male consulted our institution due to worsening of right hip pain for approximately one month. The patient had no apparent functional disorders besides rigidity of the right ankle secondary to childhood poliomyelitis. Plain radiographs demonstrated narrowing of the right hip joint space. Magnetic resonance imaging (MRI) showed unusual findings in the right gluteus medius muscle, suspecting a malignant musculoskeletal tumor. Further examinations clarified acute inflammation caused by Staphylococcus aureus with no atypia. After treatment, serum inflammatory markers normalized and MRI showed homogeneous fat signal intensity in the muscle, which was consistent with poliomyelitis. Total hip arthroplasty was performed due to progression of osteoarthritis. Intraoperative findings showed flaccidity of the gluteus medius muscle, and histological examination of the specimen also was compatible with poliomyelitis. Postoperatively there was no hip instability and the patient has been able to resume his previous physical activity. To our knowledge, this is the first report regarding polio survivors combined with septic arthritis, and sole MRI examination was unable to lead to the diagnosis. The current patient demonstrates the possibility that the involved muscles in poliomyelitis exist even in asymptomatic regions, which will be helpful for accurate diagnosis and life guidance in polio survivors. PMID:27069705

  18. MRI simulator: a teaching tool for radiology

    NASA Astrophysics Data System (ADS)

    Rundle, Debra A.; Kishore, Sheel; Seshadri, Sridhar B.; Wehrli, Felix W.

    1990-08-01

    The increasing use of magnetic resonance imaging (MRI) as a clinical modality has put an enormous burden on medical institutions to cost-effectively teach Mill scanning techniques to technologists and physicians. Since MRI scanner time is a scarce resource, it would be ideal if the teaching could be effectively performed off-line. In order to meet this goal, the Radiology Department has designed and developed a Magnetic Resonance Imaging Simulator. The Simulator in its current implementation mimics the General Electric Signa scanner's user-interface for image acquisition. The design is general enough to be applied to other MRI scanners. One unique feature of the simulator is its incorporation of an image-synthesis module which permits the user to derive images for any arbitrary combination of pulsing parameters for spin-echo, gradient-echo, and inversion recovery pulse sequences. These images are computed in five seconds. The development platform chosen is a standard Apple Macintosh-Il computer with no specialized hardware peripherals. The user-interface is implemented in HyperCard. All other software development including synthesis and display functions are implemented under the MPW 'C' environment. The scan parameters, demographics and images are tracked using an Oracle database. Images are currently stored on magnetic disk but could be stored on optical media with minimal effort.

  19. Hyperpolarized and inert gas MRI: the future.

    PubMed

    Couch, Marcus J; Blasiak, Barbara; Tomanek, Boguslaw; Ouriadov, Alexei V; Fox, Matthew S; Dowhos, Krista M; Albert, Mitchell S

    2015-04-01

    Magnetic resonance imaging (MRI) is a potentially ideal imaging modality for noninvasive, nonionizing, and longitudinal assessment of disease. Hyperpolarized (HP) agents have been developed in the past 20 years for MR imaging, and they have the potential to vastly improve MRI sensitivity for the diagnosis and management of various diseases. The polarization of nuclear magnetic resonance (NMR)-sensitive nuclei other than (1)H (e.g., (3)He, (129)Xe) can be enhanced by a factor of up to 100,000 times above thermal equilibrium levels, which enables direct detection of the HP agent with no background signal. In this review, a number of HP media applications in MR imaging are discussed, including HP (3)He and (129)Xe lung imaging, HP (129)Xe brain imaging, and HP (129)Xe biosensors. Inert fluorinated gas MRI, which is a new lung imaging technique that does not require hyperpolarization, is also briefly discussed. This technique will likely be an important future direction for the HP gas lung imaging community.

  20. DT-MRI segmentation using graph cuts

    NASA Astrophysics Data System (ADS)

    Weldeselassie, Yonas T.; Hamarneh, Ghassan

    2007-03-01

    An important problem in medical image analysis is the segmentation of anatomical regions of interest. Once regions of interest are segmented, one can extract shape, appearance, and structural features that can be analyzed for disease diagnosis or treatment evaluation. Diffusion tensor magnetic resonance imaging (DT-MRI) is a relatively new medical imaging modality that captures unique water diffusion properties and fiber orientation information of the imaged tissues. In this paper, we extend the interactive multidimensional graph cuts segmentation technique to operate on DT-MRI data by utilizing latest advances in tensor calculus and diffusion tensor dissimilarity metrics. The user interactively selects certain tensors as object ("obj") or background ("bkg") to provide hard constraints for the segmentation. Additional soft constraints incorporate information about both regional tissue diffusion as well as boundaries between tissues of different diffusion properties. Graph cuts are used to find globally optimal segmentation of the underlying 3D DT-MR image among all segmentations satisfying the constraints. We develop a graph structure from the underlying DT-MR image with the tensor voxels corresponding to the graph vertices and with graph edge weights computed using either Log-Euclidean or the J-divergence tensor dissimilarity metric. The topology of our segmentation is unrestricted and both obj and bkg segments may consist of several isolated parts. We test our method on synthetic DT data and apply it to real 2D and 3D MRI, providing segmentations of the corpus callosum in the brain and the ventricles of the heart.

  1. Biomimetic phantom for cardiac diffusion MRI

    PubMed Central

    Teh, Irvin; Zhou, Feng‐Lei; Hubbard Cristinacce, Penny L.; Parker, Geoffrey J.M.

    2015-01-01

    Purpose Diffusion magnetic resonance imaging (MRI) is increasingly used to characterize cardiac tissue microstructure, necessitating the use of physiologically relevant phantoms for methods development. Existing phantoms are generally simplistic and mostly simulate diffusion in the brain. Thus, there is a need for phantoms mimicking diffusion in cardiac tissue. Materials and Methods A biomimetic phantom composed of hollow microfibers generated using co‐electrospinning was developed to mimic myocardial diffusion properties and fiber and sheet orientations. Diffusion tensor imaging was carried out at monthly intervals over 4 months at 9.4T. 3D fiber tracking was performed using the phantom and compared with fiber tracking in an ex vivo rat heart. Results The mean apparent diffusion coefficient and fractional anisotropy of the phantom remained stable over the 4‐month period, with mean values of 7.53 ± 0.16 × 10‐4 mm2/s and 0.388 ± 0.007, respectively. Fiber tracking of the 1st and 3rd eigenvectors generated analogous results to the fiber and sheet‐normal direction respectively, found in the left ventricular myocardium. Conclusion A biomimetic phantom simulating diffusion in the heart was designed and built. This could aid development and validation of novel diffusion MRI methods for investigating cardiac microstructure, decrease the number of animals and patients needed for methods development, and improve quality control in longitudinal and multicenter cardiac diffusion MRI studies. J. MAGN. RESON. IMAGING 2016;43:594–600. PMID:26213152

  2. Late-Onset Langerhans Cell Histiocytosis with Cerebellar Ataxia as an Initial Symptom

    PubMed Central

    Pyun, Jung-Min; Park, Hyeyoung; Moon, Kyung Chul; Jeon, Beomseok

    2016-01-01

    Late-onset progressive cerebellar ataxia is a diagnostic challenge because of a poor correlation between genotype and phenotype, and a broad range of secondary causes that extend beyond the neurological field. We report the case of a 45-year-old woman admitted after 2 years of slowly progressing cerebellar ataxia, dysarthria, and emotional instability. Notably, she was diagnosed with diabetes insipidus at the age of 35. As ‘idiopathic cerebellar ataxia’ was suspected, diagnostic tests, including genetic testing as well as serum and cerebrospinal fluid analyses, and brain magnetic resonance imaging (MRI) were performed. All results were normal except those of MRI, performed 9 months prior to admission, which showed multiple dot-like white matter lesions with unclear cause. On a repeated brain MRI, a new lesion presenting as a 1.5-cm-sized highly enhancing mass attached to the right frontal skull was found. A sharply marginated lytic skull defect was also evident on skull X-ray, which corresponded to the lesion mass. Given these new radiological findings, a systemic review of the patient's medical history for rare secondary causes of cerebellar ataxia was performed, with particular attention to her past ‘diabetes insipidus’. The mass, lytic lesion of the skull, white matter lesion, diabetes insipidus, and cerebellar ataxia all suggested a final diagnosis of Langerhans cell histiocytosis (LCH), which was confirmed histopathologically. This is a rare case of late-onset LCH with an unusual initial symptom which underlines the importance of carefully reviewing the patient's medical history and broadening the search for etiologies beyond the nervous system. PMID:27920713

  3. A personalized history of EEG-fMRI integration.

    PubMed

    Laufs, Helmut

    2012-08-15

    In this personalized review, the history of EEG recorded simultaneously with functional MRI (EEG-fMRI) is summarized. A brief overview is given of the hardware development followed by a discussion of EEG-fMRI applications. The technique's development was clinically motivated in the context of epilepsy. Accordingly, the evolution of studies trying to identify with EEG-fMRI the origin of individual epileptiform discharges up to those revealing general mechanisms of epilepsy syndromes is sketched. In epilepsy centers experienced with the methodology, EEG-fMRI has found its place in the presurgical evaluation of patients. In cognitive neuroscience, the multimodal technique has significantly contributed to the understanding of phenomena of the resting state and neuronal oscillations. While most of the studies discussed relate EEG to fMRI by means of prediction, the development of forward models facilitating the symmetrical 'fusion' of EEG and fMRI data is the subject of current neuro-computational research. Recently, intracranial EEG has been safely recorded during (functional) MRI broadly extending the perspectives for epilepsy and research into neurovascular coupling. EEG-fMRI has evolved into a mature, generally accessible and in principle easily applicable technique, which is a great achievement. Because this at the same time bears the risk of unreflected use, EEG-fMRI safety issues are also highlighted.

  4. MRI-Safe Robot for Endorectal Prostate Biopsy

    PubMed Central

    Stoianovici, Dan; Kim, Chunwoo; Srimathveeravalli, Govindarajan; Sebrecht, Peter; Petrisor, Doru; Coleman, Jonathan; Solomon, Stephen B.; Hricak, Hedvig

    2014-01-01

    This paper reports the development of an MRI-Safe robot for direct (interventional) MRI-guided endorectal prostate biopsy. The robot is constructed of nonmagnetic and electrically nonconductive materials, and is electricity free, using pneumatic actuation and optical sensors. Targeting biopsy lesions of MRI abnormality presents substantial clinical potential for the management of prostate cancer. The paper describes MRI-Safe requirements, presents the kinematic architecture, design and construction of the robot, and a comprehensive set of preclinical tests for MRI compatibility and needle targeting accuracy. The robot has a compact and simple 3 degree-of-freedom (DoF) structure, two for orienting a needle-guide and one to preset the depth of needle insertion. The actual insertion is performed manually through the guide and up to the preset depth. To reduce the complexity and size of the robot next to the patient, the depth setting DoF is remote. Experimental results show that the robot is safe to use in any MRI environment (MRI-Safe). Comprehensive MRI tests show that the presence and motion of the robot in the MRI scanner cause virtually no image deterioration or signal to noise ratio (SNR) change. Robot’s accuracy in bench test, CT-guided in-vitro, MRI-guided in-vitro and animal tests are 0.37mm, 1.10mm, 2.09mm, and 2.58mm respectively. These values are acceptable for clinical use. PMID:25378897

  5. Preoperative and surveillance MR imaging of patients undergoing cytoreductive surgery and heated intraperitoneal chemotherapy

    PubMed Central

    2016-01-01

    MR imaging provides considerable advantages for imaging patients with peritoneal tumor. Its inherently superior contrast resolution compared to CT allows MRI to more accurately depict small peritoneal tumors that are often missed on other imaging tests. Combining different contrast mechanisms including diffusion-weighted (DW) MRI and gadolinium-enhanced MRI provides a powerful tool for preoperative and surveillance imaging in patients being considered for cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC). PMID:26941984

  6. 30 CFR 218.54 - Late payments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Late payments. 218.54 Section 218.54 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR MINERALS REVENUE MANAGEMENT COLLECTION OF MONIES AND PROVISION FOR GEOTHERMAL CREDITS AND INCENTIVES Oil and Gas, General § 218.54 Late...

  7. Cycads: Fossil evidence of late paleozoic origin

    USGS Publications Warehouse

    Mamay, S.H.

    1969-01-01

    Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.

  8. 12 CFR 706.4 - Late charges.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Late charges. 706.4 Section 706.4 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS UNFAIR OR DECEPTIVE ACTS OR PRACTICES § 706.4 Late charges. (a) In connection with collecting a debt arising out of...

  9. 12 CFR 706.4 - Late charges.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Late charges. 706.4 Section 706.4 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS UNFAIR OR DECEPTIVE ACTS OR PRACTICES § 706.4 Late charges. (a) In connection with collecting a debt arising out of...

  10. 12 CFR 706.4 - Late charges.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Late charges. 706.4 Section 706.4 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS UNFAIR OR DECEPTIVE ACTS OR PRACTICES § 706.4 Late charges. (a) In connection with collecting a debt arising out of...

  11. 12 CFR 706.4 - Late charges.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Late charges. 706.4 Section 706.4 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS UNFAIR OR DECEPTIVE ACTS OR PRACTICES § 706.4 Late charges. (a) In connection with collecting a debt arising out of...

  12. 40 CFR 209.16 - Late intervention.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Late intervention. 209.16 Section 209.16 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS... Hearings for Orders Issued Under Section 11(d) of the Noise Control Act § 209.16 Late...

  13. Cycads: fossil evidence of late paleozoic origin.

    PubMed

    Mamay, S H

    1969-04-18

    Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.

  14. 37 CFR 385.4 - Late payments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 385.4 Patents, Trademarks, and Copyrights COPYRIGHT ROYALTY BOARD, LIBRARY OF CONGRESS RATES AND TERMS... AND DISTRIBUTING OF PHYSICAL AND DIGITAL PHONORECORDS Physical Phonorecord Deliveries, Permanent Digital Downloads and Ringtones § 385.4 Late payments. A Licensee shall pay a late fee of 1.5% per...

  15. Late-onset offending: fact or fiction.

    PubMed

    Wiecko, Filip M

    2014-01-01

    This research focuses on a detailed exploration of late-onset offending. Using the National Youth Survey, this work seeks to answer three questions. First, is late-onset offending a real phenomenon? Second, if late onset does exist, is the evidence for it conditioned by how we define crime and delinquency? Finally, is late-onset offending an artifact of measurement methodology? Most literature evidencing late onset relies on official police contact and arrest data. Propensity or control theories in general posit that late onset should not exist. Propensity, namely self-control, should be instilled early in life and if absent, results in early initiation into crime and delinquency. Research in developmental psychology seems to support this notion. The findings from this study indicate that late-onset offending is almost nonexistent when self-reported measures are used leading one to conclude that contemporary evidence for late-onset is heavily conditioned by how we measure crime and delinquency. A comprehensive discussion includes future directions for research, and implications for theory development and methodology.

  16. Late Registration: May It Rest in Peace

    ERIC Educational Resources Information Center

    O'Banion, Terry

    2012-01-01

    Almost every institution of higher education engages in late registration. But evidence is mounting that the practice, originally intended to keep the doors of opportunity open for students as long as possible, wreaks havoc on the ability of colleges to achieve the goals of the emerging completion agenda. Despite best intentions, late registration…

  17. Microtesla MRI with dynamic nuclear polarization

    PubMed Central

    Zotev, Vadim S.; Owens, Tuba; Matlashov, Andrei N.; Savukov, Igor M.; Gomez, John J.; Espy, Michelle A.

    2010-01-01

    Magnetic resonance imaging at microtesla fields is a promising imaging method that combines the pre-polarization technique and broadband signal reception by superconducting quantum interference device (SQUID) sensors to enable in vivo MRI at microtesla-range magnetic fields similar in strength to the Earth magnetic field. Despite significant advances in recent years, the potential of microtesla MRI for biomedical imaging is limited by its insufficient signal-to-noise ratio due to a relatively low sample polarization. Dynamic nuclear polarization (DNP) is a widely used approach that allows polarization enhancement by two-four orders of magnitude without an increase in the polarizing field strength. In this work, the first implementation of microtesla MRI with Overhauser DNP and SQUID signal detection is described. The first measurements of carbon-13 NMR spectra at microtesla fields are also reported. The experiments were performed at the measurement field of 96 microtesla, corresponding to Larmor frequency of 4 kHz for protons and 1 kHz for carbon-13. The Overhauser DNP was carried out at 3.5 –5.7 mT field using rf irradiation at 120 MHz. Objects for imaging included water phantoms and a cactus plant. Aqueous solutions of metabolically relevant sodium bicarbonate, pyruvate, alanine, and lactate, labeled with carbon-13, were used for NMR studies. All the samples were doped with TEMPO free radicals. The Overhauser DNP enabled nuclear polarization enhancement by factor as high as −95 for protons and as high as −200 for carbon-13, corresponding to thermal polarizations at 0.33 T and 1.1 T fields, respectively. These results demonstrate that SQUID-based microtesla MRI can be naturally combined with Overhauser DNP in one system, and that its signal-to-noise performance is greatly improved in this case. They also suggest that microtesla MRI can become an efficient tool for in vivo imaging of hyperpolarized carbon-13, produced by the low-temperature dissolution DNP

  18. An MRI-Compatible Robotic System With Hybrid Tracking for MRI-Guided Prostate Intervention

    PubMed Central

    Krieger, Axel; Iordachita, Iulian I.; Guion, Peter; Singh, Anurag K.; Kaushal, Aradhana; Ménard, Cynthia; Pinto, Peter A.; Camphausen, Kevin; Fichtinger, Gabor

    2012-01-01

    This paper reports the development, evaluation, and first clinical trials of the access to the prostate tissue (APT) II system—a scanner independent system for magnetic resonance imaging (MRI)-guided transrectal prostate interventions. The system utilizes novel manipulator mechanics employing a steerable needle channel and a novel six degree-of-freedom hybrid tracking method, comprising passive fiducial tracking for initial registration and subsequent incremental motion measurements. Targeting accuracy of the system in prostate phantom experiments and two clinical human-subject procedures is shown to compare favorably with existing systems using passive and active tracking methods. The portable design of the APT II system, using only standard MRI image sequences and minimal custom scanner interfacing, allows the system to be easily used on different MRI scanners. PMID:22009867

  19. Preliminary Evaluation of a MRI-compatible Modular Robotic System for MRI-guided Prostate Interventions.

    PubMed

    Song, Sang-Eun; Cho, Nathan; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare; Fichtinger, Gabor; Iordachita, Iulian

    2010-09-26

    Magnetic Resonance Imaging (MRI) guided robotic interventions have been introduced in order to advance prostate cancer detection and treatment. To overcome problems of such robotic interventions, we have been developing a pneumatically actuated MRI-compatible modular robotic system for MRI-guided transperineal prostate intervention and its interventional procedure. For system evaluation, a series of experiments have been conducted and this paper reports a needle insertion experiment using prostate phantom and patient mockup trials. The needle insertion experiment resulted in noticeable consistent error in one direction, which we will investigate further. Nonetheless, patient mockup experiences suggest that the modular robotic system and its interventional procedure are well integrated and implemented in clinical environment.

  20. Preliminary Evaluation of a MRI-compatible Modular Robotic System for MRI-guided Prostate Interventions

    PubMed Central

    Song, Sang-Eun; Cho, Nathan; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare; Fichtinger, Gabor; Iordachita, Iulian

    2010-01-01

    Magnetic Resonance Imaging (MRI) guided robotic interventions have been introduced in order to advance prostate cancer detection and treatment. To overcome problems of such robotic interventions, we have been developing a pneumatically actuated MRI-compatible modular robotic system for MRI-guided transperineal prostate intervention and its interventional procedure. For system evaluation, a series of experiments have been conducted and this paper reports a needle insertion experiment using prostate phantom and patient mockup trials. The needle insertion experiment resulted in noticeable consistent error in one direction, which we will investigate further. Nonetheless, patient mockup experiences suggest that the modular robotic system and its interventional procedure are well integrated and implemented in clinical environment. PMID:21132087

  1. Low-field MRI can be more sensitive than high-field MRI

    NASA Astrophysics Data System (ADS)

    Coffey, Aaron M.; Truong, Milton L.; Chekmenev, Eduard Y.

    2013-12-01

    MRI signal-to-noise ratio (SNR) is the key factor for image quality. Conventionally, SNR is proportional to nuclear spin polarization, which scales linearly with magnetic field strength. Yet ever-stronger magnets present numerous technical and financial limitations. Low-field MRI can mitigate these constraints with equivalent SNR from non-equilibrium ‘hyperpolarization' schemes, which increase polarization by orders of magnitude independently of the magnetic field. Here, theory and experimental validation demonstrate that combination of field independent polarization (e.g. hyperpolarization) with frequency optimized MRI detection coils (i.e. multi-turn coils using the maximum allowed conductor length) results in low-field MRI sensitivity approaching and even rivaling that of high-field MRI. Four read-out frequencies were tested using samples with identical numbers of 1H and 13C spins. Experimental SNRs at 0.0475 T were ∼40% of those obtained at 4.7 T. Conservatively, theoretical SNRs at 0.0475 T 1.13-fold higher than those at 4.7 T were possible despite an ∼100-fold lower detection frequency, indicating feasibility of high-sensitivity MRI without technically challenging, expensive high-field magnets. The data at 4.7 T and 0.0475 T was obtained from different spectrometers with different RF probes. The SNR comparison between the two field strengths accounted for many differences in parameters such as system noise figures and variations in the probe detection coils including Q factors and coil diameters.

  2. WE-G-BRD-09: Novel MRI Compatible Electron Accelerator for MRI-Linac Radiotherapy

    SciTech Connect

    Whelan, B; Keall, P; Gierman, S; Schmerge, J; Holloway, L; Fahrig, R

    2015-06-15

    Purpose: MRI guided radiotherapy is a rapidly growing field; however current linacs are not designed to operate in MRI fringe fields. As such, current MRI- Linac systems require magnetic shielding, impairing MR image quality and system flexibility. Here, we present a bespoke electron accelerator concept with robust operation in in-line magnetic fields. Methods: For in-line MRI-Linac systems, electron gun performance is the major constraint on accelerator performance. To overcome this, we propose placing a cathode directly within the first accelerating cavity. Such a configuration is used extensively in high energy particle physics, but not previously for radiotherapy. Benchmarked computational modelling (CST, Darmstadt, Germany) was employed to design and assess a 5.5 cell side coupled accelerator with a temperature limited thermionic cathode in the first accelerating cell. This simulation was coupled to magnetic fields from a 1T MRI model to assess robustness in magnetic fields for Source to Isocenter Distance between 1 and 2 meters. Performance was compared to a conventional electron gun based system in the same magnetic field. Results: A temperature limited cathode (work function 1.8eV, temperature 1245K, emission constant 60A/K/cm{sup 2}) will emit a mean current density of 24mA/mm{sup 2} (Richardson’s Law). We modeled a circular cathode with radius 2mm and mean current 300mA. Capture efficiency of the device was 43%, resulting in target current of 130 mA. The electron beam had a FWHM of 0.2mm, and mean energy of 5.9MeV (interquartile spread of 0.1MeV). Such an electron beam is suitable for radiotherapy, comparing favourably to conventional systems. This model was robust to operation the MRI fringe field, with a maximum current loss of 6% compared to 85% for the conventional system. Conclusion: The bespoke electron accelerator is robust to operation in in-line magnetic fields. This will enable MRI-Linacs with no accelerator magnetic shielding, and minimise

  3. 19F MRI for quantitative in vivo cell tracking

    PubMed Central

    Srinivas, Mangala; Heerschap, Arend; Ahrens, Eric T.; Figdor, Carl G.; de Vries, I. Jolanda M.

    2010-01-01

    Cellular therapy, including stem cell transplants and dendritic cell vaccines, is typically monitored for dosage optimization, accurate delivery and localization using non-invasive imaging, of which magnetic resonance imaging (MRI) is a key modality. 19F MRI retains the advantages of MRI as an imaging modality, while allowing direct detection of labelled cells for unambiguous identification and quantification, unlike typical metal-based contrast agents. Recent developments in 19F MRI-based in vivo cell quantification, the existing clinical use of 19F compounds and current explosive interest in cellular therapeutics have brought 19F imaging technology closer to clinical application. We review the application of 19F MRI to cell tracking, discussing intracellular 19F labels, cell labelling and in vivo quantification, as well as the potential clinical use of 19F MRI. PMID:20427096

  4. Fundamentals of tracer kinetics for dynamic contrast-enhanced MRI.

    PubMed

    Koh, Tong San; Bisdas, Sotirios; Koh, Dow Mu; Thng, Choon Hua

    2011-12-01

    Tracer kinetic methods employed for quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) share common roots with earlier tracer studies involving arterial-venous sampling and other dynamic imaging modalities. This article reviews the essential foundation concepts and principles in tracer kinetics that are relevant to DCE MRI, including the notions of impulse response and convolution, which are central to the analysis of DCE MRI data. We further examine the formulation and solutions of various compartmental models frequently used in the literature. Topics of recent interest in the processing of DCE MRI data, such as the account of water exchange and the use of reference tissue methods to obviate the measurement of an arterial input, are also discussed. Although the primary focus of this review is on the tracer models and methods for T(1) -weighted DCE MRI, some of these concepts and methods are also applicable for analysis of dynamic susceptibility contrast-enhanced MRI data.

  5. Late-Glacial to Late-holocene Shifts in Global Precipitation Delta(sup 18)O

    NASA Technical Reports Server (NTRS)

    Jasechko, S.; Lechler, A.; Pausata, F.S.R.; Fawcett, P.J.; Gleeson, T.; Cendon, D.I.; Galewsky, J.; LeGrande, A. N.; Risi, C.; Sharp, Z. D.; Welker, J. M.; Werner, M.; Yoshimura, K.

    2015-01-01

    Reconstructions of Quaternary climate are often based on the isotopic content of paleo-precipitation preserved in proxy records. While many paleo-precipitation isotope records are available, few studies have synthesized these dispersed records to explore spatial patterns of late-glacial precipitation delta(sup 18)O. Here we present a synthesis of 86 globally distributed groundwater (n 59), cave calcite (n 15) and ice core (n 12) isotope records spanning the late-glacial (defined as 50,000 to 20,000 years ago) to the late-Holocene (within the past 5000 years). We show that precipitation delta(sup 18)O changes from the late-glacial to the late-Holocene range from -7.1% (delta(sup 18)O(late-Holocene) > delta(sup 18)O(late-glacial) to +1.7% (delta(sup 18)O(late-glacial) > delta(sup 18)O(late-Holocene), with the majority (77) of records having lower late-glacial delta(sup 18)O than late-Holocene delta(sup 18)O values. High-magnitude, negative precipitation delta(sup 18)O shifts are common at high latitudes, high altitudes and continental interiors.

  6. Breast Cancer in the Elderly: Is MRI Helpful?

    PubMed

    Pilewskie, Melissa; Hirsch, Allison; Eaton, Anne; Stempel, Michelle; Gemignani, Mary L

    2015-01-01

    Appropriate use of magnetic resonance imaging (MRI) in elderly breast cancer (BC) patients remains unclear; we sought to identify the indications and implications of MRI use in our elderly BC population. Women 70 years of age or older at first BC diagnosis with an MRI performed at our institution either perioperatively or in follow-up were included from a prospectively maintained database from 2000 to 2010. Univariate logistic regression was used to test associations with disease identified by MRI only (additional ipsilateral, contralateral, or new cancer) following perioperative MRI. 305 BCs were imaged in 286 patients. 133 were imaged with MRI in the perioperative setting alone, 88 had only follow-up MRIs after BC treatment, and 65 had both. Indications for perioperative MRI include: extent of disease evaluation (181; 91%); occult primary (10; 5%); high-risk screening (5; 3%); and abnormal physical exam with negative conventional imaging (2; 1%). Disease identified by MRI only for occult primary cases was 4/10 (40%; 95% confidence interval: 12.2-73.8%) and 14/181 (7.7%; 95% confidence interval: 4.3-12.6%) for perioperative MRIs performed for extent of disease evaluation. Analysis of imaging and tumor characteristics failed to find significant predictors of disease identified by MRI only. A total of 369 post-treatment follow-up MRIs were performed in 148 patients with a median of 2 MRIs per patient (range 1-8), with seven cases of disease identified by MRI only (1.9%; 95% confidence interval: 0.8-3.9%). MRI had the greatest benefit in women presenting with an occult primary cancer and minimal additional benefit in elderly patients with BC undergoing MRI imaging for extent of disease evaluation or in post-treatment surveillance.

  7. CT and MRI in the Evaluation of Thoracic Aortic Diseases

    PubMed Central

    2013-01-01

    Computed tomography (CT) and magnetic resonance imaging (MRI) are the most commonly used imaging examinations to evaluate thoracic aortic diseases because of their high spatial and temporal resolutions, large fields of view, and multiplanar imaging reconstruction capabilities. CT and MRI play an important role not only in the diagnosis of thoracic aortic disease but also in the preoperative assessment and followup after treatment. In this review, the CT and MRI appearances of various acquired thoracic aortic conditions are described and illustrated. PMID:24396601

  8. Cysticercosis of the masseter: MRI and sonographic correlation

    PubMed Central

    Nagarjuna, M; Belaval, V; Shetty, S; Salins, P C

    2015-01-01

    Cysticercal involvement of the masseter is an uncommon manifestation of a relatively common parasitic infestation. Sonographic evaluation of many isolated cases of cysticercosis has been extensively described. However, there are scanty reports on MRI appearance of cysticercal involvement of the masseter. This report presents classical imaging appearance of cysticercal involvement of the masseter on sonography and MRI. The pattern of the disease and MRI appearance of lesions in the masseter, highlighting the role of diffusion-weighted images, are described. PMID:25734242

  9. Mycobacterium Xenopi Found Incidentally on MRI of the Cervical Spine

    DTIC Science & Technology

    2010-01-01

    Mycobacterium Xenopi Found Incidentally on MRI of the Cervical Spine Military Medicine Radiology Corner, Vol. 175. January, 2010 Radiology Corner...Mycobacterium Xenopi Found Incidentally on MRI of the Cervical Spine Guarantor: Chris Walker1 Contributors: Chris Walker; 1 Col Les Folio...Mycobacterium xenopi in her lung. A mass was incidentally noted in the right upper apex on an MRI ordered to evaluate a subluxation seen in her cervical

  10. Adaptive image guided brachytherapy for cervical cancer: A combined MRI-/CT-planning technique with MRI only at first fraction

    PubMed Central

    Nesvacil, Nicole; Pötter, Richard; Sturdza, Alina; Hegazy, Neamat; Federico, Mario; Kirisits, Christian

    2013-01-01

    Purpose To investigate and test the feasibility of adaptive 3D image based BT planning for cervix cancer patients in settings with limited access to MRI, using a combination of MRI for the first BT fraction and planning of subsequent fractions on CT. Material and methods For 20 patients treated with EBRT and HDR BT with tandem/ring applicators two sets of treatment plans were compared. Scenario one is based on the “gold standard” with individual MRI-based treatment plans (applicator reconstruction, target contouring and dose optimization) for two BT applications with two fractions each. Scenario two is based on one initial MRI acquisition with an applicator in place for the planning of the two fractions of the first BT application and reuse of the target contour delineated on MRI for subsequent planning of the second application on CT. Transfer of the target from MRI of the first application to the CT of the second one was accomplished by use of an automatic applicator-based image registration procedure. Individual dose optimization of the second BT application was based on the transferred MRI target volume and OAR structures delineated on CT. DVH parameters were calculated for transferred target structures (virtual dose from MRI/CT plan) and CT-based OAR. The quality of the MRI/CT combination method was investigated by evaluating the CT-based dose distributions on MRI-based target and OAR contours of the same application (real dose from MRI/CT plan). Results The mean difference between the MRI based target volumes (HR CTVMRI2) and the structures transferred from MRI to CT (HR CTVCT2) was −1.7 ± 6.6 cm3 (−2.9 ± 20.4%) with a median of −0.7 cm3. The mean difference between the virtual and the real total D90, based on the MRI/CT combination technique was −1.5 ± 4.3 Gy EQD2. This indicates a small systematic underestimation of the real D90. Conclusions A combination of MRI for first fraction and subsequent CT based planning is feasible and easy

  11. Cholesterol and late-life cognitive decline.

    PubMed

    van Vliet, Peter

    2012-01-01

    High cholesterol levels are a major risk factor for cardiovascular disease, but their role in dementia and cognitive decline is less clear. This review highlights current knowledge on the role of cholesterol in late-life cognitive function, cognitive decline, and dementia. When measured in midlife, high cholesterol levels associate with an increased risk of late-life dementia and cognitive decline. However, when measured in late-life, high cholesterol levels show no association with cognitive function, or even show an inverse relation. Although statin treatment has been shown to associate with a lower risk of dementia and cognitive decline in observational studies, randomized controlled trials show no beneficial effect of statin treatment on late-life cognitive function. Lowering cholesterol levels may impair brain function, since cholesterol is essential for synapse formation and maturation and plays an important role in the regulation of signal transduction through its function as a component of the cell membrane. However, membrane cholesterol also plays a role in the formation and aggregation of amyloid-β. Factors that influence cholesterol metabolism, such as dietary intake, are shown to play a role in late-life cognitive function and the risk of dementia. In conclusion, cholesterol associates with late-life cognitive function, but the association is strongly age-dependent. There is no evidence that treatment with statins in late-life has a beneficial effect on cognitive function.

  12. Late Cenozoic intraplate faulting in eastern Australia

    NASA Astrophysics Data System (ADS)

    Babaahmadi, Abbas; Rosenbaum, Gideon

    2014-12-01

    The intensity and tectonic origin of late Cenozoic intraplate deformation in eastern Australia is relatively poorly understood. Here we show that Cenozoic volcanic rocks in southeast Queensland have been deformed by numerous faults. Using gridded aeromagnetic data and field observations, structural investigations were conducted on these faults. Results show that faults have mainly undergone strike-slip movement with a reverse component, displacing Cenozoic volcanic rocks ranging in ages from ˜31 to ˜21 Ma. These ages imply that faulting must have occurred after the late Oligocene. Late Cenozoic deformation has mostly occurred due to the reactivation of major faults, which were active during episodes of basin formation in the Jurassic-Early Cretaceous and later during the opening of the Tasman and Coral Seas from the Late Cretaceous to the early Eocene. The wrench reactivation of major faults in the late Cenozoic also gave rise to the occurrence of brittle subsidiary reverse strike-slip faults that affected Cenozoic volcanic rocks. Intraplate transpressional deformation possibly resulted from far-field stresses transmitted from the collisional zones at the northeast and southeast boundaries of the Australian plate during the late Oligocene-early Miocene and from the late Miocene to the Pliocene. These events have resulted in the hitherto unrecognized reactivation of faults in eastern Australia.

  13. Current Status of Hybrid PET/MRI in Oncologic Imaging

    PubMed Central

    Rosenkrantz, Andrew B.; Friedman, Kent; Chandarana, Hersh; Melsaether, Amy; Moy, Linda; Ding, Yu-Shin; Jhaveri, Komal; Beltran, Luis; Jain, Rajan

    2016-01-01

    OBJECTIVE This review article explores recent advancements in PET/MRI for clinical oncologic imaging. CONCLUSION Radiologists should understand the technical considerations that have made PET/MRI feasible within clinical workflows, the role of PET tracers for imaging various molecular targets in oncology, and advantages of hybrid PET/MRI compared with PET/CT. To facilitate this understanding, we discuss clinical examples (including gliomas, breast cancer, bone metastases, prostate cancer, bladder cancer, gynecologic malignancy, and lymphoma) as well as future directions, challenges, and areas for continued technical optimization for PET/MRI. PMID:26491894

  14. The role of MRI in musculoskeletal practice: a clinical perspective

    PubMed Central

    Dean Deyle, Gail

    2011-01-01

    This clinical perspective presents an overview of current and potential uses for magnetic resonance imaging (MRI) in musculoskeletal practice. Clinical practice guidelines and current evidence for improved outcomes will help providers determine the situations when an MRI is indicated. The advanced competency standard of examination used by physical therapists will be helpful to prevent overuse of musculoskeletal imaging, reduce diagnostic errors, and provide the appropriate clinical context to pathology revealed on MRI. Physical therapists are diagnostically accurate and appropriately conservative in their use of MRI consistent with evidence-based principles of diagnosis and screening. PMID:22851878

  15. The initial Trinidad experience with Cine MRI in clinical cardiology.

    PubMed

    Thomas, C N; Maharaj, P; Bodapati, S; John, R; Rahaman, R; Henry, R; Brann, S

    2002-03-01

    We describe the initial Trinidad experience with Magnetic Resonance Imaging (MRI) and Cine MRI as a diagnostic tool in clinical cardiology. Six patients from the following categories were referred for Cine MRI evaluation: congenital heart disease, valvular heart disease, aortic diseases, cardiomyopathy and intracardiac mass. All patients underwent echocardiography. MRI and Cine MRI were performed on all patients using a Siemens Magnetom 1.0 Tesla MR system at MRI Trinidad and Tobago Ltd. Selected patients underwent Angiography and/or computed tomography (CT) scanning. Clinical data and images of the six patients evaluated are described. MRI and Cine MRI provided excellent anatomical and functional details of the heart and aorta in five patients with dissection of the aorta, aneurysm of the ascending aorta, suspected left ventricular apical thrombus, infiltrative cardiomyopathy and arrhythmogenic right ventricular dysplasia. Technical difficulty was experienced with one patient who had a congenital defect (common atrium). In this study, Cine MRI provided excellent images in all but one patient. This new noninvasive technique enhanced diagnostic capabilities and facilitated management in patients with certain cardiovascular diseases.

  16. Anisotropic phantom to calibrate high-q diffusion MRI methods

    NASA Astrophysics Data System (ADS)

    Komlosh, M. E.; Benjamini, D.; Barnett, A. S.; Schram, V.; Horkay, F.; Avram, A. V.; Basser, P. J.

    2017-02-01

    A silicon oil-filled glass capillary array is proposed as an anisotropic diffusion MRI phantom. Together with a computational/theoretical pipeline these provide a gold standard for calibrating and validating high-q diffusion MRI experiments. The phantom was used to test high angular resolution diffusion imaging (HARDI) and double pulsed-field gradient (d-PFG) MRI acquisition schemes. MRI-based predictions of microcapillary diameter using both acquisition schemes were compared with results from optical microscopy. This phantom design can be used for quality control and quality assurance purposes and for testing and validating proposed microstructure imaging experiments and the processing pipelines used to analyze them.

  17. MRI findings of benign monomelic amyotrophy of lower limb.

    PubMed

    Hamano, T; Mutoh, T; Hirayama, M; Ito, K; Kimura, M; Aita, T; Kiyosawa, K; Ohtaki, T; Kuriyama, M

    1999-06-01

    We report here magnetic resonance imaging (MRI) findings of two patients with benign monomelic amyotrophy of lower limb. Both subjects showed unilateral amyotrophy of the lower limb with a benign clinical course, and the affected muscles demonstrated neurogenic changes. On T1- and T2-weighted MRI, marked atrophy and increased signal intensity were found mainly in gastrocnemius and soleus muscles. Moreover, MRI examination also revealed that thigh muscles including semitendinosus, semimembranosus, and vastus intermedius and lateralis muscles were involved in one of the patients. We concluded that muscle MRI is very useful for detecting affected muscles, especially deep skeletal muscles in patients with benign monomelic amyotrophy of lower limb.

  18. Early and Late Responses to Ion Irradiation

    NASA Astrophysics Data System (ADS)

    Schulte, Reinhard; Ling, Ted

    Early and late responses to ion beam therapy (IBT) are the result of complex interactions between host, dose volume, and radiobiological factors. Our understanding of these early and late tissue responses has improved greatly with the accumulation of laboratory and clinical experience with proton and heavy ion irradiation. With photon therapy becoming increasingly conformal, many concepts developed for 3D conformal radiotherapy and intensity modulated radiation therapy with photons are also applicable to IBT. This chapter reviews basic concepts and experimental data of early and late tissue responses to protons and ions.

  19. Biodegradable Magnetic Particles for Cellular MRI

    NASA Astrophysics Data System (ADS)

    Nkansah, Michael Kwasi

    Cell transplantation has the potential to treat numerous diseases and injuries. While magnetic particle-enabled, MRI-based cell tracking has proven useful for visualizing the location of cell transplants in vivo, current formulations of particles are either too weak to enable single cell detection or have non-degradable polymer matrices that preclude clinical translation. Furthermore, the off-label use of commercial agents like Feridex®, Bangs beads and ferumoxytol for cell tracking significantly stunts progress in the field, rendering it needlessly susceptible to market externalities. The recent phasing out of Feridex from the market, for example, heightens the need for a dedicated agent specifically designed for MRI-based cell tracking. To this end, we engineered clinically viable, biodegradable particles of iron oxide made using poly(lactide-co-glycolide) (PLGA) and demonstrated their utility in two MRI-based cell tracking paradigms in vivo. Both micro- and nanoparticles (2.1±1.1 μm and 105±37 nm in size) were highly magnetic (56.7-83.7 wt% magnetite), and possessed excellent relaxometry (r2* relaxivities as high as 614.1 s-1mM-1 and 659.1 s -1mM-1 at 4.7 T respectively). Magnetic PLGA micropartides enabled the in vivo monitoring of neural progenitor cell migration to the olfactory bulb in rat brains over 2 weeks at 11.7 T with ˜2-fold greater contrast-to-noise ratio and ˜4-fold better sensitivity at detecting migrated cells in the olfactory bulb than Bangs beads. Highly magnetic PLGA nanoparticles enabled MRI detection (at 11.7 T) of up to 10 rat mesenchymal cells transplanted into rat brain at 100-μm resolution. Highly magnetic PLGA particles were also shown to degrade by 80% in mice liver over 12 weeks in vivo. Moreover, no adverse effects were observed on cellular viability and function in vitro after labeling a wide range of cells. Magnetically labeled rat mesenchymal and neural stem cells retained their ability to differentiate into multiple

  20. Imaging Non-Specific Wrist Pain: Interobserver Agreement and Diagnostic Accuracy of SPECT/CT, MRI, CT, Bone Scan and Plain Radiographs

    PubMed Central

    Huellner, Martin W.; Bürkert, Alexander; Strobel, Klaus; Pérez Lago, María del Sol; Werner, Lennart; Hug, Urs; von Wartburg, Urs; Seifert, Burkhardt; Veit-Haibach, Patrick

    2013-01-01

    Purpose Chronic hand and wrist pain is a common clinical issue for orthopaedic surgeons and rheumatologists. The purpose of this study was 1. To analyze the interobserver agreement of SPECT/CT, MRI, CT, bone scan and plain radiographs in patients with non-specific pain of the hand and wrist, and 2. to assess the diagnostic accuracy of these imaging methods in this selected patient population. Materials and Methods Thirty-two consecutive patients with non-specific pain of the hand or wrist were evaluated retrospectively. All patients had been imaged by plain radiographs, planar early-phase imaging (bone scan), late-phase imaging (SPECT/CT including bone scan and CT), and MRI. Two experienced and two inexperienced readers analyzed the images with a standardized read-out protocol. Reading criteria were lesion detection and localisation, type and etiology of the underlying pathology. Diagnostic accuracy and interobserver agreement were determined for all readers and imaging modalities. Results The most accurate modality for experienced readers was SPECT/CT (accuracy 77%), followed by MRI (56%). The best performing, though little accurate modality for inexperienced readers was also SPECT/CT (44%), followed by MRI and bone scan (38% each). The interobserver agreement of experienced readers was generally high in SPECT/CT concerning lesion detection (kappa 0.93, MRI 0.72), localisation (kappa 0.91, MRI 0.75) and etiology (kappa 0.85, MRI 0.74), while MRI yielded better results on typification of lesions (kappa 0.75, SPECT/CT 0.69). There was poor agreement between experienced and inexperienced readers in SPECT/CT and MRI. Conclusions SPECT/CT proved to be the most helpful imaging modality in patients with non-specific wrist pain. The method was found reliable, providing high interobserver agreement, being outperformed by MRI only concerning the typification of lesions. We believe it is beneficial to integrate SPECT/CT into the diagnostic imaging algorithm of chronic wrist

  1. Replication of Functional MRI Detection of Deception

    PubMed Central

    Kozel, F. Andrew; Laken, Steven J.; Johnson, Kevin A.; Boren, Bryant; Mapes, Kimberly S.; Morgan, Paul S.; George, Mark S.

    2009-01-01

    Background Several studies support the use of fMRI for detecting deception. There have been, however, no reported replications on different scanners or at different locations. In a previous study, deception was accurately detected in at least 90% of the participants in two independent cohorts. This study attempted to replicate those findings using a different scanner and location. Methods Healthy participants 18–50 years of age were recruited from the local community. After providing written informed consent, participants were screened to ensure that they were healthy, not taking any medications, and safe to have an MRI. For the testing paradigm, subjects chose one of two objects (ring or watch) to “steal” and placed it in their locker. Participants were then scanned while being visually presented with a series of questions. Functional MRI analysis was performed in the same manner as described in Kozel et al. 2005. A Chi-Squared test was used to test for a significant difference between the results in the previous study and in this replication study. Results Thirty subjects (20 women, mean age 29.0±6.5 years) were scanned with one subject being noncompliant with the protocol. Twenty-five of twenty-nine (86%) participants were correctly identified when being deceptive. There was no statistical difference between the accuracy rate obtained in this study (25/29) versus the previous study (28/31) (Chi-Squared, χ2=0.246, p=0.6197). Conclusions Our methodology for detecting deception was successfully replicated at a different site suggesting that this methodology is robust and independent of both scanner and location. PMID:19844599

  2. Novel brain MRI abnormalities in Gitelman syndrome

    PubMed Central

    Norbash, Alexander; Vattoth, Surjith

    2015-01-01

    Gitelman syndrome is an autosomal recessive renal tubular disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia and hypocalciuria. The syndrome is caused by a defective thiazide-sensitive sodium chloride co-transporter in the distal convoluted tubules of the kidneys. Gitelman syndrome could be confused with Bartter syndrome; the main differentiating feature is the presence of low urinary calcium excretion in the former. Descriptions of neuroradiological imaging findings associated with Gitelman syndrome are very scarce in the literature and include basal ganglia calcification, idiopathic intracranial hypertension and sclerochoroidal calcification. Cauda equina syndrome-like presentation has been reported, but without any corresponding imaging findings on lumbar spine MRI. We report a 13-year-old male with Gitelman syndrome who presented with altered mental status following a fall and scalp laceration and unremarkable brain CT, followed during hospitalization by somnolence and seizures. Metabolically the patient demonstrated hypokalemia and hypomagnesemia. MRI demonstrated features of encephalopathy including predominantly right-sided cerebral hemispheric signal abnormality and cytotoxic edema, with bilateral symmetric involvement of the thalami, midbrain tegmentum and tectum and cerebellar dentate nuclei. MRI after five months obtained during a later episode of encephalopathy showed resolution of the signal abnormalities with setting in of brain atrophy and also areas of newly developed cytotoxic edema in the left thalamus, bilateral dorsal midbrain and right greater than left dentate nuclei. The described abnormalities, either recurrent or in isolation, have not previously been published in patients with Gitelman syndrome. We believe that the findings are due to alteration of respiratory chain function secondary to the metabolic derangement and hence have a similar imaging appearance as encephalopathy related to mitochondrial cytopathy or

  3. Motion prediction in MRI-guided radiotherapy based on interleaved orthogonal cine-MRI

    NASA Astrophysics Data System (ADS)

    Seregni, M.; Paganelli, C.; Lee, D.; Greer, P. B.; Baroni, G.; Keall, P. J.; Riboldi, M.

    2016-01-01

    In-room cine-MRI guidance can provide non-invasive target localization during radiotherapy treatment. However, in order to cope with finite imaging frequency and system latencies between target localization and dose delivery, tumour motion prediction is required. This work proposes a framework for motion prediction dedicated to cine-MRI guidance, aiming at quantifying the geometric uncertainties introduced by this process for both tumour tracking and beam gating. The tumour position, identified through scale invariant features detected in cine-MRI slices, is estimated at high-frequency (25 Hz) using three independent predictors, one for each anatomical coordinate. Linear extrapolation, auto-regressive and support vector machine algorithms are compared against systems that use no prediction or surrogate-based motion estimation. Geometric uncertainties are reported as a function of image acquisition period and system latency. Average results show that the tracking error RMS can be decreased down to a [0.2; 1.2] mm range, for acquisition periods between 250 and 750 ms and system latencies between 50 and 300 ms. Except for the linear extrapolator, tracking and gating prediction errors were, on average, lower than those measured for surrogate-based motion estimation. This finding suggests that cine-MRI guidance, combined with appropriate prediction algorithms, could relevantly decrease geometric uncertainties in motion compensated treatments.

  4. Motion prediction in MRI-guided radiotherapy based on interleaved orthogonal cine-MRI.

    PubMed

    Seregni, M; Paganelli, C; Lee, D; Greer, P B; Baroni, G; Keall, P J; Riboldi, M

    2016-01-21

    In-room cine-MRI guidance can provide non-invasive target localization during radiotherapy treatment. However, in order to cope with finite imaging frequency and system latencies between target localization and dose delivery, tumour motion prediction is required. This work proposes a framework for motion prediction dedicated to cine-MRI guidance, aiming at quantifying the geometric uncertainties introduced by this process for both tumour tracking and beam gating. The tumour position, identified through scale invariant features detected in cine-MRI slices, is estimated at high-frequency (25 Hz) using three independent predictors, one for each anatomical coordinate. Linear extrapolation, auto-regressive and support vector machine algorithms are compared against systems that use no prediction or surrogate-based motion estimation. Geometric uncertainties are reported as a function of image acquisition period and system latency. Average results show that the tracking error RMS can be decreased down to a [0.2; 1.2] mm range, for acquisition periods between 250 and 750 ms and system latencies between 50 and 300 ms. Except for the linear extrapolator, tracking and gating prediction errors were, on average, lower than those measured for surrogate-based motion estimation. This finding suggests that cine-MRI guidance, combined with appropriate prediction algorithms, could relevantly decrease geometric uncertainties in motion compensated treatments.

  5. Clinical image: MRI during migraine with aura

    SciTech Connect

    McNeal, A.C.

    1996-03-01

    Migraine refers to severe headaches that are usually unilateral, throbbing, and associated with nausea, vomiting, photophobia, and phonophobia. Migraine with aura (formerly called {open_quotes}classic migraine{close_quotes}) consists of the headache preceded or accompanied by neurological dysfunction. This dysfunction (aura) usually involves visual and sensory symptoms. The patient described herein experienced migraine with aura. MRI during and after the attack showed a reversible abnormality of the right posterior cerebral artery, with no parenchymal lesions. This appears to be the first report of abnormal MR vascular imaging during migraine with aura. 10 refs., 2 figs.

  6. Brain Morphometry using MRI in Schizophrenia Patients

    NASA Astrophysics Data System (ADS)

    Abanshina, I.; Pirogov, Yu.; Kupriyanov, D.; Orlova, V.

    2010-01-01

    Schizophrenia has been the focus of intense neuroimaging research. Although its fundamental pathobiology remains elusive, neuroimaging studies provide evidence of abnormalities of cerebral structure and function in patients with schizophrenia. We used morphometry as a quantitative method for estimation of volume of brain structures. Seventy eight right-handed subjects aged 18-45 years were exposed to MRI-examination. Patients were divided into 3 groups: patients with schizophrenia, their relatives and healthy controls. The volumes of interested structures (caudate nucleus, putamen, ventricles, frontal and temporal lobe) were measured using T2-weighted MR-images. Correlations between structural differences and functional deficit were evaluated.

  7. Threats to ultra-high-field MRI

    NASA Astrophysics Data System (ADS)

    Le Bihan, Denis

    2009-08-01

    In 2004 the European Commission (EC) adopted a directive restricting occupational exposure to electromagnetic fields. This directive (2004/40/CE), which examines the possible health risks of the electromagnetic fields from mobile phones, Wi-Fi, Bluetooth and other devices, concluded that upper limits on radiation and applied electromagnetic fields are necessary to prevent workers from suffering any undue acute health effects. But although not initially intended, the biggest impact of the directive could be on magnetic resonance imaging (MRI), which is used in hospitals worldwide to produce images of unrivalled quality of the brain and other soft tissues.

  8. TH-A-BRF-11: Image Intensity Non-Uniformities Between MRI Simulation and Diagnostic MRI

    SciTech Connect

    Paulson, E

    2014-06-15

    Purpose: MRI simulation for MRI-based radiotherapy demands that patients be setup in treatment position, which frequently involves use of alternative radiofrequency (RF) coil configurations to accommodate immobilized patients. However, alternative RF coil geometries may exacerbate image intensity non-uniformities (IINU) beyond those observed in diagnostic MRI, which may challenge image segmentation and registration accuracy as well as confound studies assessing radiotherapy response when MR simulation images are used as baselines for evaluation. The goal of this work was to determine whether differences in IINU exist between MR simulation and diagnostic MR images. Methods: ACR-MRI phantom images were acquired at 3T using a spin-echo sequence (TE/TR:20/500ms, rBW:62.5kHz, TH/skip:5/5mm). MR simulation images were obtained by wrapping two flexible phased-array RF coils around the phantom. Diagnostic MR images were obtained by placing the phantom into a commercial phased-array head coil. Pre-scan normalization was enabled in both cases. Images were transferred offline and corrected for IINU using the MNI N3 algorithm. Coefficients of variation (CV=σ/μ) were calculated for each slice. Wilcoxon matched-pairs and Mann-Whitney tests compared CV values between original and N3 images and between MR simulation and diagnostic MR images. Results: Significant differences in CV were detected between original and N3 images in both MRI simulation and diagnostic MRI groups (p=0.010, p=0.010). In addition, significant differences in CV were detected between original MR simulation and original and N3 diagnostic MR images (p=0.0256, p=0.0016). However, no significant differences in CV were detected between N3 MR simulation images and original or N3 diagnostic MR images, demonstrating the importance of correcting MR simulation images beyond pre-scan normalization prior to use in radiotherapy. Conclusions: Alternative RF coil configurations used in MRI simulation can Result in

  9. A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments.

    PubMed

    Khachaturian, Mark Haig

    2010-01-01

    Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic).

  10. Late Amazonian Glaciations in Utopia Planitia, Mars

    NASA Astrophysics Data System (ADS)

    Osinski, G. R.; Capitan, R. D.; Kerrigan, M.; Barry, N.; Blain, S.

    2012-03-01

    We present evidence from western Utopia Planitia, including lineated valley fill and lobate debris aprons, for widespread glaciations over a large expanse of the northern plains and dichotomy boundary during Late Amazonian times.

  11. 24 CFR 200.88 - Late charge.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement Generally... Requirements for Existing Projects Mortgage Provisions § 200.88 Late charge. The mortgage may provide for...

  12. 24 CFR 200.88 - Late charge.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement Generally... Requirements for Existing Projects Mortgage Provisions § 200.88 Late charge. The mortgage may provide for...

  13. Palaeoclimate: CO2 and late Palaeozoic glaciation

    NASA Astrophysics Data System (ADS)

    Myers, Timothy S.

    2016-11-01

    Large glacial-interglacial fluctuations occurred during the late Palaeozoic. Geochemical and fossil data show these cycles were marked by coincident shifts in the carbon cycle and terrestrial biosphere.

  14. Linking MRI Postprocessing with Magnetic Source Imaging in MRI-negative Epilepsy

    PubMed Central

    Wang, Zhong I.; Alexopoulos, Andreas V.; Jones, Stephen E.; Najm, Imad M.; Ristic, Aleksandar; Wong, Chong; Prayson, Richard; Schneider, Felix; Kakisaka, Yosuke; Wang, Shuang; Bingaman, William; Gonzalez-Martinez, Jorge A.; Burgess, Richard C.

    2015-01-01

    Objective MRI-negative (MRI–) pharmacoresistant focal epilepsy (PFE) patients are most challenging for epilepsy surgical management. This study utilizes a voxel-based MRI postprocessing technique, implemented using a morphometric analysis program (MAP), aiming to facilitate detection of subtle focal cortical dysplasia (FCD) in MRI– patients. Furthermore, the study examines the concordance between MAP-identified regions and localization from magnetic source imaging (MSI). Methods Included in this retrospective study were 25 MRI– surgical patients. MAP was performed on T1-weighted MRI, with comparison to a normal database. The pertinence of MAP+ areas was confirmed by MSI, surgical outcome and pathology. Analyses of MAP and MSI were performed blindly from patients' clinical information and independently from each other. Results The detection rate of subtle changes by MAP was 48% (12/25). Once MAP+ areas were resected, patients were more likely to be seizure-free (p = 0.02). There were no false positives in the 25 age-matched normal controls. Seven patients had a concordant MSI correlate. Patients in whom a concordant area was identified by both MAP and MSI had a significantly higher chance of achieving a seizure-free outcome following complete resection of this area (p = 0.008). In the 9 resected MAP+ areas, pathology revealed FCD type IA in 7 and type IIB in 2. Interpretation MAP shows promise in identifying subtle FCD abnormalities and increasing the diagnostic yield of conventional MRI visual analysis in presurgical evaluation of PFE. Concordant MRI postprocessing and MSI analyses may lead to the noninvasive identification of a structurally and electrically abnormal subtle lesion that can be surgically targeted. PMID:24777960

  15. Voxel-based Morphometric MRI Post-processing in MRI-negative Epilepsies

    PubMed Central

    Wang, ZI; Jones, SE; Jaisani, Z; Najm, IM; Prayson, RA; Burgess, RC; Krishnan, B; Ristic, A; Wong, CH; Bingaman, W; Gonzalez-Martinez, JA; Alexopoulos, AV

    2015-01-01

    Objective In the presurgical workup of MRI-negative (MRI−, or “nonlesional”) pharmacoresistant focal epilepsy (PFE) patients, discovering a previously undetected lesion can drastically change the evaluation and likely improve surgical outcome. Our study utilizes a voxel-based MRI post-processing technique, implemented in a morphometric analysis program (MAP), to facilitate detection of subtle abnormalities in a consecutive cohort of MRI− surgical candidates. Methods Included in this retrospective study was a consecutive cohort of 150 MRI-surgical patients. MAP was performed on T1-weighted MRI, with comparison to a scanner-specific normal database. Review and analysis of MAP were performed blinded to patients’ clinical information. The pertinence of MAP+ areas was confirmed by surgical outcome and pathology. Results MAP showed a 43% positive rate, sensitivity of 0.9 and specificity of 0.67. Overall, patients with MAP+ region completely resected had the best seizure outcomes, followed by the MAP− patients, and patients who had no/partial resection of the MAP+ region had the worst outcome (p<0.001). Subgroup analysis revealed that visually identified subtle findings are more likely correct if also MAP+. False-positive rate in 52 normal controls was 2%. Surgical pathology of the resected MAP+ areas contained mainly non-balloon-cell FCD. Multiple MAP+ regions were present in 7% of patients. Conclusions MAP can be a practical and valuable tool to: (1) guide the search for subtle MRI abnormalities, and (2) confirm visually identified questionable abnormalities in patients with PFE due to suspected FCD. A MAP+ region, when concordant with the patient’s electro-clinical presentation, should provide a legitimate target for surgical exploration. PMID:25807928

  16. Late extrusion of alloplastic orbital floor implants.

    PubMed

    Brown, A E; Banks, P

    1993-06-01

    Complications following the use of alloplastic orbital floor implants are well documented but it is not widely recognised that these can occur many years after initial treatment. Three patients who presented with late extrusion of an implant through the facial skin are reported. This complication occurred 10, 16 and 17 years respectively after treatment of the orbital floor fracture. The tissue reaction to silicone rubber and Teflon inplants is reviewed and the possible cause for this late complication is discussed.

  17. Late-onset Visual Loss in Osteopetrosis

    PubMed Central

    Wangai, Abdul-Majid; Waa, Sheila; Wangai, Maryam; Amayo, Erastus; Olunya, Oluoch

    2011-01-01

    Late-onset visual loss is a complication of nerve entrapment and increased intracranial pressure. We hereby describe the first case in Eastern Africa. A 23 year-old lady presented with sudden blindness, headaches and body weakness. She had previously had treatment for multiple unexplained fractures. Findings of optic nerve entrapment explained this blindness. This case highlights the need to have a high index of suspicion in cases of unexplained fractures with late-onset blindness. PMID:22087385

  18. Assessment of Liver Fibrosis Using Fast Strain-Encoded (FSENC) MRI Driven by Inherent Cardiac Motion

    PubMed Central

    Harouni, Ahmed A.; Gharib, Ahmed M.; Osman, Nael F.; Morse, Caryn; Heller, Theo; Abd-Elmoniem, Khaled Z.

    2014-01-01

    Purpose An external driver-free MRI method for assessment of liver fibrosis offers a promising non-invasive tool for diagnosis and monitoring of liver disease. Lately, the heart’s intrinsic motion and MR tagging have been utilized for the quantification of liver strain. However, MR tagging requires multiple breath-hold acquisitions and substantial post-processing. This work proposes a fast strain-encoded (FSENC) MRI methodology to measure the peak strain (Sp) in the liver’s left lobe, which is in close proximity and caudal to the heart. Additionally, a new method is introduced to measure heart-induced shear wave velocity (SWV) inside the liver. Methods Phantom and in-vivo experiments (11 healthy subjects, and 11 patients with liver fibrosis) were conducted. Reproducibility experiments were performed in seven healthy subjects. Results Peak liver strain Sp significantly decreased in fibrotic liver compared healthy liver (6.46%±2.27% vs. 12.49%±1.76%, P<0.05). Heart-induced SWV significantly increased in patients compared to healthy subjects (0.15±0.04 m/s vs. 0.63±0.32 m/s, P<0.05). Reproducibility analysis yielded no significant difference in Sp (P=0.47) or SWV (P=0.56). Conclusion Accelerated external driver-free noninvasive assessment of left liver lobe strain and shear wave velocity is feasible using strain-encoded MRI. The two measures significantly separate healthy subjects from patients with fibrotic liver. PMID:25081734

  19. Late effects of blood and marrow transplantation.

    PubMed

    Inamoto, Yoshihiro; Lee, Stephanie J

    2017-04-01

    Hematopoietic cell transplantation is a curative treatment for a variety of hematologic diseases. Advances in transplantation technology have reduced early transplant-related mortality and expanded application of transplantation to older patients and to a wider variety of diseases. Management of late effects after transplantation is increasingly important for a growing number of long-term survivors that is estimated to be half a million worldwide. Many studies have shown that transplant survivors suffer from significant late effects that adversely affect morbidity, mortality, working status and quality of life. Late effects include diseases of the cardiovascular, pulmonary, and endocrine systems, dysfunction of the thyroid gland, gonads, liver and kidneys, infertility, iron overload, bone diseases, infection, solid cancer, and neuropsychological effects. The leading causes of late mortality include recurrent malignancy, lung diseases, infection, secondary cancers and chronic graft-versus-host disease. The aim of this review is to facilitate better care of adult transplant survivors by summarizing accumulated evidence, new insights, and practical information about individual late effects. Further research is needed to understand the biology of late effects allowing better prevention and treatment strategies to be developed.

  20. Crossmodal plasticity in the fusiform gyrus of late blind individuals during voice recognition.

    PubMed

    Hölig, Cordula; Föcker, Julia; Best, Anna; Röder, Brigitte; Büchel, Christian

    2014-12-01

    Blind individuals are trained in identifying other people through voices. In congenitally blind adults the anterior fusiform gyrus has been shown to be active during voice recognition. Such crossmodal changes have been associated with a superiority of blind adults in voice perception. The key question of the present functional magnetic resonance imaging (fMRI) study was whether visual deprivation that occurs in adulthood is followed by similar adaptive changes of the voice identification system. Late blind individuals and matched sighted participants were tested in a priming paradigm, in which two voice stimuli were subsequently presented. The prime (S1) and the target (S2) were either from the same speaker (person-congruent voices) or from two different speakers (person-incongruent voices). Participants had to classify the S2 as either coming from an old or a young person. Only in late blind but not in matched sighted controls, the activation in the anterior fusiform gyrus was modulated by voice identity: late blind volunteers showed an increase of the BOLD signal in response to person-incongruent compared with person-congruent trials. These results suggest that the fusiform gyrus adapts to input of a new modality even in the mature brain and thus demonstrate an adult type of crossmodal plasticity.

  1. An asymmetrical relationship between verbal and visual thinking: Converging evidence from behavior and fMRI.

    PubMed

    Amit, Elinor; Hoeflin, Caitlyn; Hamzah, Nada; Fedorenko, Evelina

    2017-03-18

    Humans rely on at least two modes of thought: verbal (inner speech) and visual (imagery). Are these modes independent, or does engaging in one entail engaging in the other? To address this question, we performed a behavioral and an fMRI study. In the behavioral experiment, participants received a prompt and were asked to either silently generate a sentence or create a visual image in their mind. They were then asked to judge the vividness of the resulting representation, and of the potentially accompanying representation in the other format. In the fMRI experiment, participants had to recall sentences or images (that they were familiarized with prior to the scanning session) given prompts, or read sentences and view images, in the control, perceptual, condition. An asymmetry was observed between inner speech and visual imagery. In particular, inner speech was engaged to a greater extent during verbal than visual thought, but visual imagery was engaged to a similar extent during both modes of thought. Thus, it appears that people generate more robust verbal representations during deliberate inner speech compared to when their intent is to visualize. However, they generate visual images regardless of whether their intent is to visualize or to think verbally. One possible interpretation of these results is that visual thinking is somehow primary, given the relatively late emergence of verbal abilities during human development and in the evolution of our species.

  2. Spectral Analysis of Non-ideal MRI Modes: The Effect of Hall Diffusion

    NASA Astrophysics Data System (ADS)

    Mohandas, Gopakumar; Pessah, Martin E.

    2017-03-01

    The effect of magnetic field diffusion on the stability of accretion disks is a problem that has attracted considerable interest of late. In particular, the Hall effect has the potential to bring about remarkable changes in the dynamical behavior of disks that are without parallel. In this paper, we conduct a systematic examination of the linear eigenmodes in a weakly magnetized differentially rotating gas with a special focus on Hall diffusion. We first develop a geometrical representation of the eigenmodes and provide a detailed quantitative description of the polarization properties of the oscillatory modes under the combined influence of the Coriolis and Hall effects. We also analyze the effects of magnetic diffusion on the structure of the unstable modes and derive analytical expressions for the kinetic and magnetic stresses and energy densities associated with the non-ideal magnetorotational instability (MRI). Our analysis explicitly demonstrates that, if the dissipative effects are relatively weak, the kinetic stresses and energies make up the dominant contribution to the total stress and energy density when the equilibrium angular momentum and magnetic field vectors are anti-parallel. This is in sharp contrast to what is observed in the case of the ideal or dissipative MRI. We conduct shearing box simulations and find very good agreement with the results derived from linear theory. Because the modes under consideration are also exact solutions of the nonlinear equations, the unconventional nature of the kinetic and magnetic stresses may have significant implications for the nonlinear evolution in some regions of protoplanetary disks.

  3. Prediction of final infarct volume on subacute MRI by quantifying cerebral edema in ischemic stroke.

    PubMed

    Tipirneni-Sajja, Aaryani; Christensen, Soren; Straka, Matus; Inoue, Manabu; Lansberg, Maarten G; Mlynash, Michael; Bammer, Roland; Parsons, Mark W; Donnan, Geoffrey A; Davis, Stephen M; Albers, Gregory W

    2016-01-01

    Final infarct volume in stroke trials is assessed on images obtained between 30 and 90 days after stroke onset. Imaging at such delayed timepoints is problematic because patients may be lost to follow-up or die before the scan. Obtaining an early assessment of infarct volume on subacute scans avoids these limitations; however, it overestimates true infarct volume because of edema. The aim of this study was to develop a novel approach to quantify edema so that final infarct volumes can be approximated on subacute scans. We analyzed data from 20 stroke patients (median age, 75 years) who had baseline, subacute (fu5d) and late (fu90d) MRI scans. Edema displaces CSF from sulci and ventricles; therefore, edema volume was estimated as change in CSF volume between baseline and spatially coregistered fu5d ADC maps. The median (interquartile range, IQR) estimated edema volume was 13.3 (7.5-37.7) mL. The fu5d lesion volumes correlated well with fu90d infarct volumes with slope: 1.24. With edema correction, fu5d infarct volumes are in close agreement, slope: 0.97 and strongly correlated with actual fu90d volumes. The median (IQR) difference between actual and predicted infarct volumes was 0.1 (-3.0-5.7) mL. In summary, this novel technique for estimation of edema allows final infarct volume to be predicted from subacute MRI.

  4. Application of micro-PIXE, MRI and light microscopy for research in wood science and dendroecology

    NASA Astrophysics Data System (ADS)

    Merela, M.; Pelicon, P.; Vavpetič, P.; Regvar, M.; Vogel-Mikuš, K.; Serša, I.; Poličnik, H.; Pokorny, B.; Levanič, T.; Oven, P.

    2009-06-01

    Beech ( Fagus sylvatica L.) branches were topped and after five months the wound response was analyzed by PIXE, 3D-MRI and light microscopy. From freshly cut and deeply frozen sample 30 μm thick longitudinal-radial tissue sections were prepared for anatomical investigations and micro-PIXE analysis. Light microscopy revealed the structural response to wounding, i.e. occurrence of the reaction zone between the exposed and dehydrated dead tissue and healthy sound wood. The reaction zone was characterized by tylosis in vessels and accumulation of colored deposits in parenchyma cells, fibres and vessels. 3D MRI of a parallel sample showed that the moisture content in the reaction zone was three times higher than in normal healthy wood. Micro-PIXE mapping at margins of compromised wood in beech revealed an increased concentration of potassium in the reaction zone. The increase in the calcium concentration was associated with the dehydrated tissue adjacent to reaction zones. In addition, micro-PIXE was used to determine the elemental distribution in annual tree rings. This may be relevant for retrospective assessment of environmental pollution in wood by measuring yearly increments as a biomonitoring tool. The analysis of European larch ( Larix decidua Mill.) wood revealed a high similarity between optical characteristics (i.e. late versus earlywood) and elemental (e.g. Cl, K, Ca, Mn, Zn) distribution.

  5. Geometric strategies for neuroanatomic analysis from MRI

    PubMed Central

    Duncan, James S.; Papademetris, Xenophon; Yang, Jing; Jackowski, Marcel; Zeng, Xiaolan; Staib, Lawrence H.

    2010-01-01

    In this paper, we describe ongoing work in the Image Processing and Analysis Group (IPAG) at Yale University specifically aimed at the analysis of structural information as represented within magnetic resonance images (MRI) of the human brain. Specifically, we will describe our applied mathematical approaches to the segmentation of cortical and subcortical structure, the analysis of white matter fiber tracks using diffusion tensor imaging (DTI), and the intersubject registration of neuroanatomical (aMRI) data sets. Many of our methods rally around the use of geometric constraints, statistical (MAP) estimation, and the use of level set evolution strategies. The analysis of gray matter structure and connecting white matter paths combined with the ability to bring all information into a common space via intersubject registration should provide us with a rich set of data to investigate structure and variation in the human brain in neuropsychiatric disorders, as well as provide a basis for current work in the development of integrated brain function–structure analysis. PMID:15501099

  6. Syringomyelia associated with adhesive spinal arachnoiditis: MRI.

    PubMed

    Inoue, Y; Nemoto, Y; Ohata, K; Daikokuya, H; Hakuba, A; Tashiro, T; Shakudo, M; Nagai, K; Nakayama, K; Yamada, R

    2001-04-01

    We reviewed the MRI of seven patients with syringomyelia associated with surgically proven adhesive spinal arachnoiditis to describe clinical and MRI findings in this condition. Using 0.5, 1.0 or 1.5 tesla units, we obtained sagittal T1- and T2-weighted spin-echo and axial T1-weighted images. Additional sagittal T2-weighted images were obtained without using motion-artefact suppression. Contrast medium was given intravenously to five patients. The syrinx cavities were thoracic in five cases, cervicothoracic in one, and extended from C4 to L1 in one. No Chiari malformation or craniovertebral junction anomaly was demonstrated. Meningeal thickening was seen on T2-weighted sagittal images only in one case. Cord deformity due to adhesion or displacement due to an associated arachnoid cyst was seen in all cases best demonstrated on axial images. Focal blurring of the syrinx wall on axial images was seen in six patients. Flow voids were seen in the syrinx fluid in all cases on T2-weighted images obtained without motion-artefact suppression. No abnormal contrast enhancement was demonstrated.

  7. MRI in necrotizing fasciitis of the extremities.

    PubMed

    Ali, S Z; Srinivasan, S; Peh, W C G

    2014-01-01

    Necrotizing fasciitis is a life-threatening soft-tissue infection of bacterial origin, which involves mainly the deep fascia. Early recognition of this condition may be hampered by the uncommon nature of the disease and non-specificity of initial clinical signs and symptoms in less fulminant cases, making the role of imaging important. MRI is the most useful imaging modality in the diagnosis of necrotizing fasciitis. The presence of thick (>3 mm) hyperintense signal in the deep fascia (particularly intermuscular fascia) on fat-suppressed T2 weighted or short tau inversion-recovery images is an important marker for necrotizing fasciitis. Contrast enhancement of the thickened necrotic fascia can be variable, with a mixed-pattern of enhancement being more commonly encountered. Involvement of multiple musculofascial compartments increases the likelihood of necrotizing fasciitis. It is important to remember that T2-hyperintense signal in the deep fascia is not specific to necrotizing fasciitis and can also be seen in cases such as non-infective inflammatory fasciitis or muscle tear. In this pictorial essay, we aim to review the MRI findings in necrotizing fasciitis, discuss its limitations and pitfalls and identify differentiating features from non-necrotizing soft-tissue infections, such as cellulitis and infective myositis/pyomyositis, conditions which may clinically mimic necrotizing fasciitis.

  8. Simulation of arthroscopic surgery using MRI data

    NASA Technical Reports Server (NTRS)

    Heller, Geoffrey; Genetti, Jon

    1994-01-01

    With the availability of Magnetic Resonance Imaging (MRI) technology in the medical field and the development of powerful graphics engines in the computer world the possibility now exists for the simulation of surgery using data obtained from an actual patient. This paper describes a surgical simulation system which will allow a physician or a medical student to practice surgery on a patient without ever entering an operating room. This could substantially lower the cost of medial training by providing an alternative to the use of cadavers. This project involves the use of volume data acquired by MRI which are converted to polygonal form using a corrected marching cubes algorithm. The data are then colored and a simulation of surface response based on springy structures is performed in real time. Control for the system is obtained through the use of an attached analog-to-digital unit. A remote electronic device is described which simulates an imaginary tool having features in common with both arthroscope and laparoscope.

  9. MRI for Crohn's Disease: Present and Future

    PubMed Central

    Yoon, Kichul; Chang, Kyu-Tae; Lee, Hong J.

    2015-01-01

    Crohn's disease (CD) is a chronic inflammatory condition with relapsing-remitting behavior, often causing strictures or penetrating bowel damage. Its lifelong clinical course necessitates frequent assessment of disease activity and complications. Computed tomography (CT) enterography has been used as primary imaging modality; however, the concern for radiation hazard limits its use especially in younger population. Magnetic resonance (MR) imaging has advantages of avoiding radiation exposure, lower incidence of adverse events, ability to obtain dynamic information, and good soft-tissue resolution. MR enterography (MRE) with oral contrast agent has been used as primary MR imaging modality of CD with high sensitivity, specificity, and interobserver agreement. The extent of inflammation as well as transmural ulcers and fibrostenotic diseases can be detected with MRE. Novel MR techniques such as diffusion-weighted MRI (DWI), motility study, PET-MRI, and molecular imaging are currently investigated for further improvement of diagnosis and management of CD. MR spectroscopy is a remarkable molecular imaging tool to analyze metabolic profile of CD with human samples such as plasma, urine, or feces, as well as colonic mucosa itself. PMID:26413543

  10. MRI in treatment of adult gliomas.

    PubMed

    Henson, John W; Gaviani, Paola; Gonzalez, R Gilberto

    2005-03-01

    Diffuse astrocytomas of the adult cerebral hemispheres are unique among tumours in human beings in the extent to which their imaging features are related to histopathological characteristics and clinical behaviour. However, understanding is still restricted about the value of imaging features in the measurement of response and of progression in these tumours. The present approach used in clinical trials, which consists of an anatomical measurement of the enhancing tumour on MRI, has many problems, and might not be acceptable as a surrogate endpoint for survival in patients with glioblastoma who are enrolled in clinical trials. Dynamic imaging techniques, such as capillary permeability mapping, are being used in studies of new drugs that target specific molecular features of gliomas; however, the validity of these techniques has not been elucidated. Diffusion imaging can be valuable for fibre-tract mapping to assist surgical planning and might become useful in measuring early response to treatment in densely cellular tumours. Functional imaging techniques can be used to localise motor, sensory, and language-control areas before surgery. Intraoperative MRI has produced improvements in the extent of tumour resection, and molecular imaging is another technique on the horizon, which could come to have a role in clinical trials in the near future. Thus, as a rapidly expanding sphere of investigation, brain-tumour imaging is producing great excitement. The aim of these new techniques is to aid the identification of more effective treatments.

  11. Neuroplasticity and MRI: A perfect match.

    PubMed

    Hamaide, Julie; De Groof, Geert; Van der Linden, Annemie

    2016-05-01

    Numerous studies have illustrated the benefits of physical workout and cognitive exercise on brain function and structure and, more importantly, on decelerating cognitive decline in old age and promoting functional rehabilitation following injury. Despite these behavioral observations, the exact mechanisms underlying these neuroplastic phenomena remain obscure. This gap illustrates the need for carefully designed in-depth studies using valid models and translational tools which allow to uncover the observed events up to the molecular level. We promote the use of in vivo magnetic resonance imaging (MRI) because it is a powerful translational imaging technique able to extract functional, structural, and biochemical information from the entire brain. Advanced processing techniques allow performing voxel-based analyses which are capable of detecting novel loci implicated in specific neuroplastic events beyond traditional regions-of-interest analyses. In addition, its non-invasive character sets it as currently the best global imaging tool for performing dynamic longitudinal studies on the same living subject, allowing thus exploring the effects of experience, training, treatment etc. in parallel to additional measures such as age, cognitive performance scores, hormone levels, and many others. The aim of this review is (i) to introduce how different animal models contributed to extend the knowledge on neuroplasticity in both health and disease, over different life stages and upon various experiences, and (ii) to illustrate how specific MRI techniques can be applied successfully to inform on the fundamental mechanisms underlying experience-dependent or activity-induced neuroplasticity including cognitive processes.

  12. Acute encephalopathy with biphasic seizures and late reduced diffusion associated with staphylococcal toxic shock syndrome caused by burns.

    PubMed

    Yokochi, Takaoki; Sakanishi, Shinpei; Ishidou, Yuuki; Kawano, Go; Matsuishi, Toyojiro; Akita, Yukihiro; Obu, Keizo

    2016-10-01

    We report a case of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) associated with toxic shock syndrome caused by burns. A one-year-old girl was admitted to our hospital for treatment of severe burns. On day 3, she exhibited a fever, generalized rash and multiple organ failure. She was diagnosed with toxic shock syndrome after burns. She had seizures with fever twice on the same day, followed by secondary seizures on day 8 and transient deterioration of the gross motor functions involved in sitting alone and rolling over. On day 9, MRI diffusion-weighted images showed bright tree appearance (BTA). We conclude that she developed AESD.

  13. Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning

    SciTech Connect

    Paulson, Eric S.; Erickson, Beth; Schultz, Chris; Allen Li, X.

    2015-01-15

    Purpose: The use of magnetic resonance imaging (MRI) in radiation oncology is expanding rapidly, and more clinics are integrating MRI into their radiation therapy workflows. However, radiation therapy presents a new set of challenges and places additional constraints on MRI compared to diagnostic radiology that, if not properly addressed, can undermine the advantages MRI offers for radiation treatment planning (RTP). The authors introduce here strategies to manage several challenges of using MRI for virtual simulation in external beam RTP. Methods: A total of 810 clinical MRI simulation exams were performed using a dedicated MRI scanner for external beam RTP of brain, breast, cervix, head and neck, liver, pancreas, prostate, and sarcoma cancers. Patients were imaged in treatment position using MRI-optimal immobilization devices. Radiofrequency (RF) coil configurations and scan protocols were optimized based on RTP constraints. Off-resonance and gradient nonlinearity-induced geometric distortions were minimized or corrected prior to using images for RTP. A multidisciplinary MRI simulation guide, along with window width and level presets, was created to standardize use of MR images during RTP. A quality assurance program was implemented to maintain accuracy and repeatability of MRI simulation exams. Results: The combination of a large bore scanner, high field strength, and circumferentially wrapped, flexible phased array RF receive coils permitted acquisition of thin slice images with high contrast-to-noise ratio (CNR) and image intensity uniformity, while simultaneously accommodating patient setup and immobilization devices. Postprocessing corrections and alternative acquisition methods were required to reduce or correct off-resonance and gradient nonlinearity induced geometric distortions. Conclusions: The methodology described herein contains practical strategies the authors have implemented through lessons learned performing clinical MRI simulation exams. In

  14. ‘Extra-operatve’ MRI (eoMRI) for Brain Tumor Surgery – Initial Results at a Single Institution

    PubMed Central

    Abd-El-Barr, Muhammad M.; Santos, Seth M.; Aglio, Linda S.; Young, Geoffrey S.; Mukundan, Srinivasan; Golby, Alexandra J.; Gormley, William B.; Dunn, Ian F.

    2015-01-01

    Background There is accumulating evidence that extent of resection (EOR) in intrinsic brain tumor surgery prolongs overall survival (OS) and progression-free survival (PFS). One of the strategies to increase EOR is the use of intraoperative MRI (ioMRI). However, considerable infrastructure investment is needed to establish and maintain a sophisticated ioMRI. We report the preliminary results of an extra-operative (eoMRI) protocol, with a focus on safety, feasibility and EOR in intrinsic brain tumor surgery. Methods Ten patients underwent an eoMRI protocol consisting of surgical resection in a conventional operating room followed by an immediate MRI in a clinical MRI scanner while the patient was still under anesthesia. If MRI suggested residual safely resectable tumor, the patient was returned to the operating room. Retrospective volumetric analysis was undertaken to investigate the percentage of tumor resected after first resection and if applicable, after further resection. Results 6 out of 10 (60%) patients were felt to require no further resection after eoMRI. The EOR in these patients was 97.8±1.8%. In the 4 patients who underwent further resection, the EOR during the original surgery was 88.5±9.5% (p =0.04). There was an average of 10.1 % more tumor removed between the first and second surgery. In 3/4 (75%) of patients who returned for further resection, gross total resection of was achieved. Conclusion An eoMRI protocol appears to be a safe and practical method to ensure maximum safe resections in patients with brain tumors and can be performed readily in all centers with MRI capability. PMID:25700968

  15. Clinical oncologic applications of PET/MRI: a new horizon

    PubMed Central

    Partovi, Sasan; Kohan, Andres; Rubbert, Christian; Vercher-Conejero, Jose Luis; Gaeta, Chiara; Yuh, Roger; Zipp, Lisa; Herrmann, Karin A; Robbin, Mark R; Lee, Zhenghong; Muzic, Raymond F; Faulhaber, Peter; Ros, Pablo R

    2014-01-01

    Positron emission tomography/magnetic resonance imaging (PET/MRI) leverages the high soft-tissue contrast and the functional sequences of MR with the molecular information of PET in one single, hybrid imaging technology. This technology, which was recently introduced into the clinical arena in a few medical centers worldwide, provides information about tumor biology and microenvironment. Studies on indirect PET/MRI (use of positron emission tomography/computed tomography (PET/CT) images software fused with MRI images) have already generated interesting preliminary data to pave the ground for potential applications of PET/MRI. These initial data convey that PET/MRI is promising in neuro-oncology and head & neck cancer applications as well as neoplasms in the abdomen and pelvis. The pediatric and young adult oncology population requiring frequent follow-up studies as well as pregnant woman might benefit from PET/MRI due to its lower ionizing radiation dose. The indication and planning of therapeutic interventions and specifically radiation therapy in individual patients could be and to a certain extent are already facilitated by performing PET/MRI. The objective of this article is to discuss potential clinical oncology indications of PET/MRI. PMID:24753986

  16. Lying about Facial Recognition: An fMRI Study

    ERIC Educational Resources Information Center

    Bhatt, S.; Mbwana, J.; Adeyemo, A.; Sawyer, A.; Hailu, A.; VanMeter, J.

    2009-01-01

    Novel deception detection techniques have been in creation for centuries. Functional magnetic resonance imaging (fMRI) is a neuroscience technology that non-invasively measures brain activity associated with behavior and cognition. A number of investigators have explored the utilization and efficiency of fMRI in deception detection. In this study,…

  17. Tracking brain arousal fluctuations with fMRI

    PubMed Central

    Chang, Catie; Leopold, David A.; Schölvinck, Marieke Louise; Mandelkow, Hendrik; Picchioni, Dante; Liu, Xiao; Ye, Frank Q.; Turchi, Janita N.; Duyn, Jeff H.

    2016-01-01

    Changes in brain activity accompanying shifts in vigilance and arousal can interfere with the study of other intrinsic and task-evoked characteristics of brain function. However, the difficulty of tracking and modeling the arousal state during functional MRI (fMRI) typically precludes the assessment of arousal-dependent influences on fMRI signals. Here we combine fMRI, electrophysiology, and the monitoring of eyelid behavior to demonstrate an approach for tracking continuous variations in arousal level from fMRI data. We first characterize the spatial distribution of fMRI signal fluctuations that track a measure of behavioral arousal; taking this pattern as a template, and using the local field potential as a simultaneous and independent measure of cortical activity, we observe that the time-varying expression level of this template in fMRI data provides a close approximation of electrophysiological arousal. We discuss the potential benefit of these findings for increasing the sensitivity of fMRI as a cognitive and clinical biomarker. PMID:27051064

  18. Functional MRI in children: clinical and research applications.

    PubMed

    Leach, James L; Holland, Scott K

    2010-01-01

    Functional MRI has become a critical research tool for evaluating brain function and developmental trajectories in children. Its clinical use in children is becoming more common. This presentation will review the basic underlying physiologic and technical aspects of fMRI, review research applications that have direct clinical relevance, and outline the current clinical uses of this technology.

  19. Simulation of phase contrast MRI of turbulent flow.

    PubMed

    Petersson, Sven; Dyverfeldt, Petter; Gårdhagen, Roland; Karlsson, Matts; Ebbers, Tino

    2010-10-01

    Phase contrast MRI is a powerful tool for the assessment of blood flow. However, especially in the highly complex and turbulent flow that accompanies many cardiovascular diseases, phase contrast MRI may suffer from artifacts. Simulation of phase contrast MRI of turbulent flow could increase our understanding of phase contrast MRI artifacts in turbulent flows and facilitate the development of phase contrast MRI methods for the assessment of turbulent blood flow. We present a method for the simulation of phase contrast MRI measurements of turbulent flow. The method uses an Eulerian-Lagrangian approach, in which spin particle trajectories are computed from time-resolved large eddy simulations. The Bloch equations are solved for each spin for a frame of reference moving along the spins trajectory. The method was validated by comparison with phase contrast MRI measurements of velocity and intravoxel velocity standard deviation (IVSD) on a flow phantom consisting of a straight rigid pipe with a stenosis. Turbulence related artifacts, such as signal drop and ghosting, could be recognized in the measurements as well as in the simulations. The velocity and the IVSD obtained from the magnitude of the phase contrast MRI simulations agreed well with the measurements.

  20. MRI for clinically suspected pediatric appendicitis: case interpretation.

    PubMed

    Moore, Michael M; Brian, James M; Methratta, Sosamma T; Hulse, Michael A; Choudhary, Arabinda K; Eggli, Kathleen D; Boal, Danielle K B

    2014-05-01

    As utilization of MRI for clinically suspected pediatric appendicitis becomes more common, there will be increased focus on case interpretation. The purpose of this pictorial essay is to share our institution's case interpretation experience. MRI findings of appendicitis include appendicoliths, tip appendicitis, intraluminal fluid-debris level, pitfalls of size measurements, and complications including abscesses. The normal appendix and inguinal appendix are also discussed.

  1. Data collection and analysis strategies for phMRI.

    PubMed

    Mandeville, Joseph B; Liu, Christina H; Vanduffel, Wim; Marota, John J A; Jenkins, Bruce G

    2014-09-01

    Although functional MRI traditionally has been applied mainly to study changes in task-induced brain function, evolving acquisition methodologies and improved knowledge of signal mechanisms have increased the utility of this method for studying responses to pharmacological stimuli, a technique often dubbed "phMRI". The proliferation of higher magnetic field strengths and the use of exogenous contrast agent have boosted detection power, a critical factor for successful phMRI due to the restricted ability to average multiple stimuli within subjects. Receptor-based models of neurovascular coupling, including explicit pharmacological models incorporating receptor densities and affinities and data-driven models that incorporate weak biophysical constraints, have demonstrated compelling descriptions of phMRI signal induced by dopaminergic stimuli. This report describes phMRI acquisition and analysis methodologies, with an emphasis on data-driven analyses. As an example application, statistically efficient data-driven regressors were used to describe the biphasic response to the mu-opioid agonist remifentanil, and antagonism using dopaminergic and GABAergic ligands revealed modulation of the mesolimbic pathway. Results illustrate the power of phMRI as well as our incomplete understanding of mechanisms underlying the signal. Future directions are discussed for phMRI acquisitions in human studies, for evolving analysis methodologies, and for interpretative studies using the new generation of simultaneous PET/MRI scanners. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'.

  2. Is joint effusion on MRI specific for haemophilia?

    PubMed

    Foppen, W; van der Schaaf, I C; Witkamp, T D; Fischer, K

    2014-07-01

    Magnetic resonance imaging (MRI) scores for haemophilic arthropathy are useful for evaluation of early and moderate arthropathy. The most recent additive International Prophylaxis Study Group (IPSG) MRI scale for haemophilic arthropathy includes joint effusion. However, it is unknown whether joint effusion is haemophilia specific. Correct interpretation of joint effusion is needed for outcome assessment of prophylactic therapies in haemophilia care. The aim of this study was to compare joint effusion on MRI between young adults with haemophilia and healthy controls. MRI's of both knees and ankles of 26 haemophilic patients (104 joints) and 30 healthy active men (120 joints) were assessed. Scans in both groups were performed in 2009/2010 and 2012 respectively. Joint effusion was measured and scored according to the MRI atlas referred by the IPSG MRI scale for haemophilic arthropathy. Median age of haemophilic patients and healthy controls was 21 and 24 years respectively. In haemophilic patients 23% of knees and 22% of ankles showed joint effusion. Healthy controls had significantly more positive scores for knee effusion (67%, P < 0.01) and a comparable scores for effusion in the ankle (17%). Joint effusion according to criteria of the IPSG MRI scale was observed significantly more often in knees of healthy controls, while findings in ankles were similar. These data suggest that joint effusion in knees and ankles is not haemophilia specific. Inclusion of joint effusion in the MRI scale is expected to reduce its specificity for haemophilic arthropathy.

  3. EEG/functional MRI in epilepsy: The Queen Square Experience.

    PubMed

    Hamandi, Khalid; Salek-Haddadi, Afraim; Fish, David R; Lemieux, Louis

    2004-01-01

    The recording of EEG during functional MRI scanning (EEG/fMRI) has opened up new dimensions in brain research. The simultaneous recording of EEG activity and its temparospatial haemodynamic correlates is a powerful tool in the non-invasive mapping of normal and pathological brain function. The technological constraints imposed by having a conductor (the EEG) within the magnetic environment of the MRI scanner have been sufficiently overcome for high quality EEG recording during MRI. The initial applications of EEG/fMRI were in the study of epileptiform discharges in epilepsy. This has been rapidly followed by studies of normal EEG rhythms and evoked response in healthy subjects. The ability to map brain areas involved in the generation of epileptiform discharges recorded on the surface EEG has been shown using EEG/fMRI in patients with epilepsy. This has potential clinical applications in providing additional localizing information in the pre-surgical workup of epilepsy patients and in gaining a greater understanding of the neurobiology of interictal epileptiform discharges and epileptic seizures. In this review we address the issues in recording EEG during fMRI and review the application of EEG/fMRI in the study of patients with epilepsy at our centre.

  4. Study Design in fMRI: Basic Principles

    ERIC Educational Resources Information Center

    Amaro, Edson, Jr.; Barker, Gareth J.

    2006-01-01

    There is a wide range of functional magnetic resonance imaging (fMRI) study designs available for the neuroscientist who wants to investigate cognition. In this manuscript we review some aspects of fMRI study design, including cognitive comparison strategies (factorial, parametric designs), and stimulus presentation possibilities (block,…

  5. Biparametric versus multiparametric MRI in the diagnosis of prostate cancer

    PubMed Central

    Logager, Vibeke; Baslev, Ingerd; Møller, Jakob M; Hansen, Rasmus Hvass; Thomsen, Henrik S

    2016-01-01

    Background Since multiparametric magnetic resonance imaging (mp-MRI) of the prostate exceeds 30 min, minimizing the evaluation time of significant (Gleason scores > 6) prostate cancer (PCa) would be beneficial. A reduced protocol might be sufficient for the diagnosis. Purpose To study whether a short unenhanced biparametric MRI (bp-MRI) matches mp-MRI in detecting significant PCa. Material and Methods A total of 204 men (median age, 65 years; mean ± SD, 64.1; range 45–75 years; median serum PSA level, 14 ng/mL; range, 2.2–120 ng/mL; median prostate volume, 60 mL; range, 23–263 mL) fulfilled the criteria for being enrolled. They underwent mp-MRI and prostate biopsy from January through June 2014. Of the included patients, 9.3% underwent prostatectomy, 90.7% had TRUS-bx, and 10.8 had MRI-targeted TRUS-bx. Two radiologists separately assessed the mp-MRI examination (T2-weighted [T2W] imaging, diffusion-weighted imaging [DWI], apparent diffusion coefficient map [ADC-map] and dynamic contrast-enhanced imaging [DCE]). Two months later, the bp-MRI version (T2W imaging, DWI, and ADC-map) was evaluated. Results Reader 1: Assessing mp-MRI: 0 false negatives, sensitivity of 1, and specificity 0.04. Assessing bp-MRI: four false negatives, sensitivity of 0.94, and specificity 0.15. Reader 2: Assessing mp-MRI: five false negatives, sensitivity of 0.93, and specificity 0.16. Assessing bp-MRI: three false negatives, sensitivity of 0.96, and specificity 0.15. Intra-reader agreement Cohen’s Kappa (κ) was 0.87 for reader 1 (95% confidence interval [CI], 0.83–0.92) and 0.84 for reader 2 (95% CI 0.78–0.89). Conclusion Bp-MRI is as good as mp-MRI at detecting PCa. A large prospective study seems to be strongly warranted. PMID:27583170

  6. Perspectives of hyperpolarized noble gas MRI beyond 3He

    NASA Astrophysics Data System (ADS)

    Lilburn, David M. L.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2013-04-01

    Nuclear Magnetic Resonance (NMR) studies with hyperpolarized (hp) noble gases are at an exciting interface between physics, chemistry, materials science and biomedical sciences. This paper intends to provide a brief overview and outlook of magnetic resonance imaging (MRI) with hp noble gases other than hp 3He. A particular focus are the many intriguing experiments with 129Xe, some of which have already matured to useful MRI protocols, while others display high potential for future MRI applications. Quite naturally for MRI applications the major usage so far has been for biomedical research but perspectives for engineering and materials science studies are also provided. In addition, the prospects for surface sensitive contrast with hp 83Kr MRI is discussed.

  7. A MRI-COMPATIBLE SYSTEM FOR WHISKER STIMULATION

    PubMed Central

    Li, Limin; Weiss, Craig; Talk, Andrew C.; Disterhoft, John F.; Wyrwicz, Alice M.

    2013-01-01

    We describe here a system for whisker stimulation designed for functional studies in high-field magnetic resonance imaging (MRI) environments. This system, which incorporates real-time optical monitoring of the vibration stimulus, can generate well-controlled and reproducible whisker deflections with amplitudes up to 2 mm and frequencies up to 75 Hz, suitable for functional magnetic resonance imaging (fMRI) studies of animals. Whiskers on either or both sides of the head can be stimulated selectively during fMRI experiments without removing the subject from the magnet. With a user-friendly graphical interface of a computer, a user can conveniently control both the whisker vibration and gating of the MR imager, and synchronize the stimulation with the fMRI acquisition to ensure precise timing of the stimulus presentation. This whisker stimulation system should facilitate a wide variety of fMRI investigations of the neural systems mediating sensory information from the whiskers. PMID:22322316

  8. Alliance for aging research AD biomarkers work group: structural MRI.

    PubMed

    Jack, Clifford R

    2011-12-01

    Biomarkers of Alzheimer's disease (AD) are increasingly important. All modern AD therapeutic trials employ AD biomarkers in some capacity. In addition, AD biomarkers are an essential component of recently updated diagnostic criteria for AD from the National Institute on Aging--Alzheimer's Association. Biomarkers serve as proxies for specific pathophysiological features of disease. The 5 most well established AD biomarkers include both brain imaging and cerebrospinal fluid (CSF) measures--cerebrospinal fluid Abeta and tau, amyloid positron emission tomography (PET), fluorodeoxyglucose (FDG) positron emission tomography, and structural magnetic resonance imaging (MRI). This article reviews evidence supporting the position that MRI is a biomarker of neurodegenerative atrophy. Topics covered include methods of extracting quantitative and semiquantitative information from structural MRI; imaging-autopsy correlation; and evidence supporting diagnostic and prognostic value of MRI measures. Finally, the place of MRI in a hypothetical model of temporal ordering of AD biomarkers is reviewed.

  9. Compressed sensing MRI: a review of the clinical literature

    PubMed Central

    Jaspan, Oren N; Fleysher, Roman

    2015-01-01

    MRI is one of the most dynamic and safe imaging techniques available in the clinic today. However, MRI acquisitions tend to be slow, limiting patient throughput and limiting potential indications for use while driving up costs. Compressed sensing (CS) is a method for accelerating MRI acquisition by acquiring less data through undersampling of k-space. This has the potential to mitigate the time-intensiveness of MRI. The limited body of research evaluating the effects of CS on MR images has been mostly positive with regards to its potential as a clinical tool. Studies have successfully accelerated MRI with this technology, with varying degrees of success. However, more must be performed before its diagnostic efficacy and benefits are clear. Studies involving a greater number radiologists and images must be completed, rating CS based on its diagnostic efficacy. Also, standardized methods for determining optimal imaging parameters must be developed. PMID:26402216

  10. Myocardial Fibrosis as an Early Manifestation of Hypertrophic Cardiomyopathy

    PubMed Central

    Ho, Carolyn Y.; López, Begoña; Coelho-Filho, Otavio R.; Lakdawala, Neal K.; Cirino, Allison L.; Jarolim, Petr; Kwong, Raymond; González, Arantxa; Colan, Steven D.; Seidman, J.G.; Díez, Javier; Seidman, Christine E.

    2011-01-01

    BACKGROUND Myocardial fibrosis is a hallmark of hypertrophic cardiomyopathy and a proposed substrate for arrhythmias and heart failure. In animal models, profibrotic genetic pathways are activated early, before hypertrophic remodeling. Data showing early profibrotic responses to sarcomere-gene mutations in patients with hypertrophic cardiomyopathy are lacking. METHODS We used echocardiography, cardiac magnetic resonance imaging (MRI), and serum biomarkers of collagen metabolism, hemodynamic stress, and myocardial injury to evaluate subjects with hypertrophic cardiomyopathy and a confirmed genotype. RESULTS The study involved 38 subjects with pathogenic sarcomere mutations and overt hypertrophic cardiomyopathy, 39 subjects with mutations but no left ventricular hypertrophy, and 30 controls who did not have mutations. Levels of serum C-terminal propeptide of type I procollagen (PICP) were significantly higher in mutation carriers without left ventricular hypertrophy and in subjects with overt hypertrophic cardiomyopathy than in controls (31% and 69% higher, respectively; P<0.001). The ratio of PICP to C-terminal telopeptide of type I collagen was increased only in subjects with overt hypertrophic cardiomyopathy, suggesting that collagen synthesis exceeds degradation. Cardiac MRI studies showed late gadolinium enhancement, indicating myocardial fibrosis, in 71% of subjects with overt hypertrophic cardiomyopathy but in none of the mutation carriers without left ventricular hypertrophy. CONCLUSIONS Elevated levels of serum PICP indicated increased myocardial collagen synthesis in sarcomere-mutation carriers without overt disease. This profibrotic state preceded the development of left ventricular hypertrophy or fibrosis visible on MRI. (Funded by the National Institutes of Health and others.) PMID:20818890

  11. Network Connectivity in Epilepsy: Resting State fMRI and EEG–fMRI Contributions

    PubMed Central

    Centeno, Maria; Carmichael, David W.

    2014-01-01

    There is a growing body of evidence pointing toward large-scale networks underlying the core phenomena in epilepsy, from seizure generation to cognitive dysfunction or response to treatment. The investigation of networks in epilepsy has become a key concept to unlock a deeper understanding of the disease. Functional imaging can provide valuable information to characterize network dysfunction; in particular resting state fMRI (RS-fMRI), which is increasingly being applied to study brain networks in a number of diseases. In patients with epilepsy, network connectivity derived from RS-fMRI has found connectivity abnormalities in a number of networks; these include the epileptogenic, cognitive and sensory processing networks. However, in majority of these studies, the effect of epileptic transients in the connectivity of networks has been neglected. EEG–fMRI has frequently shown networks related to epileptic transients that in many cases are concordant with the abnormalities shown in RS studies. This points toward a relevant role of epileptic transients in the network abnormalities detected in RS-fMRI studies. In this review, we summarize the network abnormalities reported by these two techniques side by side, provide evidence of their overlapping findings, and discuss their significance in the context of the methodology of each technique. A number of clinically relevant factors that have been associated with connectivity changes are in turn associated with changes in the frequency of epileptic transients. These factors include different aspects of epilepsy ranging from treatment effects, cognitive processes, or transition between different alertness states (i.e., awake–sleep transition). For RS-fMRI to become a more effective tool to investigate clinically relevant aspects of epilepsy it is necessary to understand connectivity changes associated with epileptic transients, those associated with other clinically relevant factors and the interaction between them

  12. MRI-based brain atrophy rates in ADNI phase 2: acceleration and enrichment considerations for clinical trials.

    PubMed

    Hua, Xue; Ching, Christopher R K; Mezher, Adam; Gutman, Boris A; Hibar, Derrek P; Bhatt, Priya; Leow, Alex D; Jack, Clifford R; Bernstein, Matt A; Weiner, Michael W; Thompson, Paul M

    2016-01-01

    The goal of this work was to assess statistical power to detect treatment effects in Alzheimer's disease (AD) clinical trials using magnetic resonance imaging (MRI)-derived brain biomarkers. We used unbiased tensor-based morphometry (TBM) to analyze n = 5,738 scans, from Alzheimer's Disease Neuroimaging Initiative 2 participants scanned with both accelerated and nonaccelerated T1-weighted MRI at 3T. The study cohort included 198 healthy controls, 111 participants with significant memory complaint, 182 with early mild cognitive impairment (EMCI) and 177 late mild cognitive impairment (LMCI), and 155 AD patients, scanned at screening and 3, 6, 12, and 24 months. The statistical power to track brain change in TBM-based imaging biomarkers depends on the interscan interval, disease stage, and methods used to extract numerical summaries. To achieve reasonable sample size estimates for potential clinical trials, the minimal scan interval was 6 months for LMCI and AD and 12 months for EMCI. TBM-based imaging biomarkers were not sensitive to MRI scan acceleration, which gave results comparable with nonaccelerated sequences. ApoE status and baseline amyloid-beta positron emission tomography data improved statistical power. Among healthy, EMCI, and LMCI participants, sample size requirements were significantly lower in the amyloid+/ApoE4+ group than for the amyloid-/ApoE4- group. ApoE4 strongly predicted atrophy rates across brain regions most affected by AD, but the remaining 9 of the top 10 AD risk genes offered no added predictive value in this cohort.

  13. fMRI alignment based on local functional connectivity patterns

    NASA Astrophysics Data System (ADS)

    Jiang, Di; Du, Yuhui; Cheng, Hewei; Jiang, Tianzi; Fan, Yong

    2012-02-01

    In functional neuroimaging studies, the inter-subject alignment of functional magnetic resonance imaging (fMRI) data is a necessary precursor to improve functional consistency across subjects. Traditional structural MRI based registration methods cannot achieve accurate inter-subject functional consistency in that functional units are not necessarily consistently located relative to anatomical structures due to functional variability across subjects. Although spatial smoothing commonly used in fMRI data preprocessing can reduce the inter-subject functional variability, it may blur the functional signals and thus lose the fine-grained information. In this paper we propose a novel functional signal based fMRI image registration method which aligns local functional connectivity patterns of different subjects to improve the inter-subject functional consistency. Particularly, the functional connectivity is measured using Pearson correlation. For each voxel of an fMRI image, its functional connectivity to every voxel in its local spatial neighborhood, referred to as its local functional connectivity pattern, is characterized by a rotation and shift invariant representation. Based on this representation, the spatial registration of two fMRI images is achieved by minimizing the difference between their corresponding voxels' local functional connectivity patterns using a deformable image registration model. Experiment results based on simulated fMRI data have demonstrated that the proposed method is more robust and reliable than the existing fMRI image registration methods, including maximizing functional correlations and minimizing difference of global connectivity matrices across different subjects. Experiment results based on real resting-state fMRI data have further demonstrated that the proposed fMRI registration method can statistically significantly improve functional consistency across subjects.

  14. A review of MRI findings in schizophrenia

    PubMed Central

    Shenton, Martha E.; Dickey, Chandlee C.; Frumin, Melissa; McCarley, Robert W.

    2009-01-01

    After more than 100 years of research, the neuropathology of schizophrenia remains unknown and this is despite the fact that both Kraepelin (1919/1971: Kraepelin,E., 1919/1971. Dementia praecox. Churchill Livingston Inc., New York) and Bleuler (1911/1950: Bleuler, E., 1911/1950. Dementia praecox or the group of schizophrenias. International Universities Press, New York), who first described ‘dementia praecox’ and the ‘ schizophrenias’, were convinced that schizophrenia would ultimately be linked to an organic brain disorder. Alzheimer (1897: Alzheimer, A., 1897. Beitrage zur pathologischen anatomie der hirnrinde und zur anatomischen grundlage einiger psychosen. Monatsschrift fur Psychiarie und Neurologie. 2, 82–120) was the first to investigate the neuropathology of schizophrenia, though he went on to study more tractable brain diseases. The results of subsequent neuropathological studies were disappointing because of conflicting findings. Research interest thus waned and did not flourish again until 1976, following the pivotal computer assisted tomography (CT) finding of lateral ventricular enlargement in schizophrenia by Johnstone and colleagues. Since that time significant progress has been made in brain imaging, particularly with the advent of magnetic resonance imaging (MRI), beginning with the first MRI study of schizophrenia by Smith and coworkers in 1984 (Smith, R.C., Calderon, M., Ravichandran, G.K., et al. (1984). Nuclear magnetic resonance in schizophrenia: A preliminary study. Psychiatry Res. 12, 137–147). MR in vivo imaging of the brain now confirms brain abnormalities in schizophrenia. The 193 peer reviewed MRI studies reported in the current review span the period from 1988 to August, 2000. This 12 year period has witnessed a burgeoning of MRI studies and has led to more definitive findings of brain abnormalities in schizophrenia than any other time period in the history of schizophrenia research. Such progress in defining the

  15. Comparison of dual-echo DSC-MRI- and DCE-MRI-derived contrast agent kinetic parameters.

    PubMed

    Quarles, C Chad; Gore, John C; Xu, Lei; Yankeelov, Thomas E

    2012-09-01

    The application of dynamic susceptibility contrast (DSC) MRI methods to assess brain tumors is often confounded by the extravasation of contrast agent (CA). Disruption of the blood-brain barrier allows CA to leak out of the vasculature leading to additional T(1), T(2) and T(2) relaxation effects in the extravascular space, thereby affecting the signal intensity time course in a complex manner. The goal of this study was to validate a dual-echo DSC-MRI approach that separates and quantifies the T(1) and T(2) contributions to the acquired signal and enables the estimation of the volume transfer constant, K(trans), and the volume fraction of the extravascular extracellular space, v(e). To test the validity of this approach, DSC-MRI- and dynamic contrast enhanced (DCE) MRI-derived K(trans) and v(e) estimates were spatially compared in both 9L and C6 rat brain tumor models. A high degree of correlation (concordance correlation coefficients >0.83, Pearson's r>0.84) and agreement was found between the DSC-MRI- and DCE-MRI-derived measurements. These results indicate that dual-echo DSC-MRI can be used to simultaneously extract reliable DCE-MRI kinetic parameters in brain tumors in addition to conventional blood volume and blood flow metrics.

  16. [Multiparametric MRI. The role of MRI techniques in the diagnosis, staging and follow up of prostate cancer].

    PubMed

    Vilanova, Joan C; Luna-Alcalá, Antonio; Boada, Maria; Barceló, Joaquim

    2015-04-01

    The current diagnosis of prostate cancer based on PSA values and systematic biopsy has limitations in its efficacy of detection and staging. Technical advances on imaging over the last decade, mainly MRI, enable improvements in the strategy of prostate cancer management in diagnosis, staging, follow up and therapy monitoring. MRI enables the combination of morphological (T2 sequences) and, at the same time, functional information by means of the application of sequences such as spectroscopy (SMRI), diffusion and dynamic intravenous contrast (CMRI) in the same study, giving the multiparametric MRI (mpMRI). Currently, it is not necessary to apply all sequences to obtain an mpMR study of optimal efficacy, so that a time shorter than 30 minutes is enough to obtain the necessary information depending on the clinical indication. The main clinical indications of prostatic MRI are a) local, regional or distance staging; b) Detection or guide for diagnostic biopsy for clinical risk suspicion or negative result in previous biopsies; c) active surveillance; and d) therapeutic monitoring. Furthermore, one of the most relevant features of prostate cancer, and a challenge for the mpMRI techniques is to be able to differentiate aggressive and non-significant neoplasias (latent). This update tries to review the current role of mpMRI in the management of prostate cancer using in combination the anatomical (T2) and functional (SMRI, DMRI and CMRI) information. We also describe the European prostate mpMRI guidelines, PI-RADS (Prostate imaging reporting data System).

  17. Epigone migraine vertigo (EMV): a late migraine equivalent.

    PubMed

    Pagnini, P; Vannucchi, P; Giannoni, B; Pecci, R

    2014-02-01

    Migrainous headache is determined by pathogenetic mechanisms that are also able to affect the peripheral and/or central vestibular system, so that vestibular symptoms may substitute and/or present with headache. We are convinced that there can be many different manifestations of vestibular disorders in migrainous patients, representing true different clinical entities due to their different characteristics and temporal relashionship with headache. Based on such considerations, we proposed a classification of vertigo and other vestibular disorders related to migraine, and believe that a particular variant of migraine-related vertigo should be introduced, namely "epigone migraine vertigo" (EMV): this could be a kind of late migraine equivalent, i.e. a kind of vertigo, migrainous in origin, starting late in the lifetime that substitutes, as an equivalent, pre-existing migraine headache. To clarify this particular clinical picture, we report three illustrative clinical cases among 28 patients collected during an observation period of 13 years (November 1991 - November 2004). For all patients, we collected complete personal clinical history. All patients underwent standard neurotological examination, looking for spontaneous-positional, gaze-evoked and caloric induced nystagmus, using an infrared video camera. We also performed a head shaking test (HST) and an head thrust test (HTT). Ocular motility was tested looking at saccades and smooth pursuit. To exclude other significant neurological pathologies, a brain magnetic resonance imaging (MRI) with gadolinium was performed. During the three months after the first visit, patients were invited to keep a diary noting frequency, intensity and duration of vertigo attacks. After that period, we suggested that they use prophylactic treatment with flunarizine (5 mg per day) and/or acetylsalicylic acid (100 mg per day), or propranolol (40 mg twice a day). All patients were again recommended to note in their diary the frequency

  18. Computerized classification of liver disease in MRI using an artificial neural network

    NASA Astrophysics Data System (ADS)

    Zhang, Xuejun; Kanematsu, Masayuki; Fujita, Hiroshi; Hara, Takeshi; Hoshi, Hiroaki

    2001-07-01

    We developed a software named LiverANN based on artificial neural network (ANN) technique for distinguishing the pathologies of focal liver lesions in magnetic resonance (MR) imaging, which helps radiologists integrate the imaging findings with different pulse sequences and raise the diagnostic accuracy even with radiologists inexperienced in liver MR imaging. In each patient, regions of focal liver lesion on T1-weighted, T2-weighted, and gadolinium-enhanced dynamic MR images obtained in the hepatic arterial and equilibrium phases were placed by a radiologist (M.K.), then the program automatically calculated the brightness and homogeneity into numerical data within the selected areas as the input signals to the ANN. The outputs from the ANN were the 5 categories of focal hepatic diseases: liver cyst, cavernous hemangioma, dysplasia, hepatocellular carcinoma, and metastasis. Fifty cases were used for training the ANN, while 30 cases for testing the performance. The result showed that the LiverANN classified 5 types of focal liver lesions with sensitivity of 93%, which demonstrated the ability of ANN to fuse the complex relationships among the image findings with different sequences, and the ANN-based software may provide radiologists with referential opinion during the radiologic diagnostic procedure.

  19. Clinical and laboratory analysis of late-onset glutaric aciduria type I (GA-I) in Uighur: A report of two cases

    PubMed Central

    Zhang, Xiaoying; Luo, Qiong

    2017-01-01

    The aim of the present study was to investigate the clinical, biochemical and genetic mutation characteristics of two cases of late-onset glutaric aciduria type I (GA-I) in Uighur. The clinical data and glutaryl-CoA dehydrogenase (GCDH) genetic test results of two cases of late-onset GA-I in Uighur were collected and analyzed, and reviewed with relevant literature. One patient with late-onset GA-I primarily exhibited clinical intermittent headache, while the other patient was asymptomatic. The urinary organic acid analysis detected a large number of glutaric acid and 3-hydroxy glutaric acid, 3-hydroxy-propionic acid. One patient exhibited white matter degeneration in cranial magnetic resonance imaging (MRI) and the other patient showed no abnormality. The two patients both exhibited c. 1204C >T, p.R402W, heterozygous mutation, and c. 532G >A, p.G178R, heterozygous mutation. Besides central nervous system infectious diseases, patients with clinical headache, cranial MRI-suggested bilateral temporal lobe arachnoid cyst and abnormal signals in the basal ganglia should be highly suspected as late-onset GA-I. Early diagnosis and correct treatment are key to improve its prognosis. PMID:28352331

  20. Single slice US-MRI registration for neurosurgical MRI-guided US

    NASA Astrophysics Data System (ADS)

    Pardasani, Utsav; Baxter, John S. H.; Peters, Terry M.; Khan, Ali R.

    2016-03-01

    Image-based ultrasound to magnetic resonance image (US-MRI) registration can be an invaluable tool in image-guided neuronavigation systems. State-of-the-art commercial and research systems utilize image-based registration to assist in functions such as brain-shift correction, image fusion, and probe calibration. Since traditional US-MRI registration techniques use reconstructed US volumes or a series of tracked US slices, the functionality of this approach can be compromised by the limitations of optical or magnetic tracking systems in the neurosurgical operating room. These drawbacks include ergonomic issues, line-of-sight/magnetic interference, and maintenance of the sterile field. For those seeking a US vendor-agnostic system, these issues are compounded with the challenge of instrumenting the probe without permanent modification and calibrating the probe face to the tracking tool. To address these challenges, this paper explores the feasibility of a real-time US-MRI volume registration in a small virtual craniotomy site using a single slice. We employ the Linear Correlation of Linear Combination (LC2) similarity metric in its patch-based form on data from MNI's Brain Images for Tumour Evaluation (BITE) dataset as a PyCUDA enabled Python module in Slicer. By retaining the original orientation information, we are able to improve on the poses using this approach. To further assist the challenge of US-MRI registration, we also present the BOXLC2 metric which demonstrates a speed improvement to LC2, while retaining a similar accuracy in this context.

  1. Complete fourier direct magnetic resonance imaging (CFD-MRI) for diffusion MRI

    PubMed Central

    Özcan, Alpay

    2013-01-01

    The foundation for an accurate and unifying Fourier-based theory of diffusion weighted magnetic resonance imaging (DW–MRI) is constructed by carefully re-examining the first principles of DW–MRI signal formation and deriving its mathematical model from scratch. The derivations are specifically obtained for DW–MRI signal by including all of its elements (e.g., imaging gradients) using complex values. Particle methods are utilized in contrast to conventional partial differential equations approach. The signal is shown to be the Fourier transform of the joint distribution of number of the magnetic moments (at a given location at the initial time) and magnetic moment displacement integrals. In effect, the k-space is augmented by three more dimensions, corresponding to the frequency variables dual to displacement integral vectors. The joint distribution function is recovered by applying the Fourier transform to the complete high-dimensional data set. In the process, to obtain a physically meaningful real valued distribution function, phase corrections are applied for the re-establishment of Hermitian symmetry in the signal. Consequently, the method is fully unconstrained and directly presents the distribution of displacement integrals without any assumptions such as symmetry or Markovian property. The joint distribution function is visualized with isosurfaces, which describe the displacement integrals, overlaid on the distribution map of the number of magnetic moments with low mobility. The model provides an accurate description of the molecular motion measurements via DW–MRI. The improvement of the characterization of tissue microstructure leads to a better localization, detection and assessment of biological properties such as white matter integrity. The results are demonstrated on the experimental data obtained from an ex vivo baboon brain. PMID:23596401

  2. Validation of the hypercapnic calibrated fMRI method using DOT-fMRI fusion imaging

    PubMed Central

    Yücel, Meryem A.; Evans, Karleyton C.; Selb, Juliette; Huppert, Theodore J.; Boas, David A.; Gagnon, Louis

    2014-01-01

    Calibrated functional Magnetic Resonance Imaging (fMRI) is a widely used method to investigate brain function in terms of physiological quantities such as the cerebral metabolic rate of oxygen (CMRO2). The first and one of the most common methods of fMRI calibration is hypercapnic calibration. This is achieved via simultaneous measures of blood-oxygenation-level dependent (BOLD) and the arterial spin labeling (ASL) signals during a functional task that evokes regional changes in CMRO2. A subsequent acquisition is then required during which the subject inhales carbon dioxide for short periods of time. A calibration constant, typically labeled M, is then estimated from the hypercapnic data and is subsequently used together with the BOLD-ASL recordings to compute evoked changes in CMRO2 during the functional task. The computation of M assumes a constant CMRO2 during the CO2 inhalation, an assumption that has been questioned since the origin of calibrated fMRI. In this study we used Diffuse Optical Tomography (DOT) together with BOLD and ASL – an alternative calibration method that does not require any gas manipulation and therefore no constant CMRO2 assumption - to cross-validate the estimation of M obtained from a traditional hypercapnic calibration. We found a high correlation between the M values (R=0.87, p<0.01) estimated using these two approaches. The findings serve to validate the hypercapnic fMRI calibration technique and suggest that the inter-subject variability routinely obtained for M is reproducible with an alternative method and might therefore reflect inter-subject physiological variability. PMID:25196509

  3. SU-E-J-239: IMRT Planning of Prostate Cancer for a MRI-Linac Based On MRI Only

    SciTech Connect

    Chen, X; Prior, P; Paulson, E; Lawton, C; Li, X

    2014-06-01

    Purpose: : To investigate dosimetric differences between MRI- and CT-based IMRT planning for prostate cancer, the impact of a magnetic field in a MRI-Linac, and to explore the feasibility of IMRT planning based on MRI alone. Methods: IMRT plans were generated based on CT and MRI images acquired on two representative prostate-cancer patients using clinical dose volume constraints. A research planning system (Monaco, Elekta), which employs a Monte Carlo dose engine and includes a perpendicular magnetic field of 1.5T from an MRI-Linac, was used. Bulk electron density assignments based on organ-specific values from ICRU 46 were used to convert MRI (T2) to pseudo CT. With the same beam configuration as in the original CT plan, 5 additional plans were generated based on CT or MRI, with or without optimization (i.e., just recalculation) and with or without the magnetic field. The plan quality in terms of commonly used dose volume (DV) parameters for all plans was compared. The statistical uncertainty on dose was < 1%. Results: For plans with the same contour set but without re-optimization, the DV parameters were different from those for the original CT plan, mostly less than 5% with a few exceptions. These differences were reduced to mostly less than 3% when the plans were re-optimized. For plans with contours from MRI, the differences in the DV parameters varied depending on the difference in the contours as compared to CT. For the optimized plans with contours from MR, the differences for PTV were less than 3%. Conclusion: The prostate IMRT plans based on MRI-only for a MR-Linac were practically similar as compared to the CT plan under the same beam and optimization configuration if the difference on the structure delineation is excluded, indicating the feasibility of using MRI-only for prostate IMRT.

  4. Development and Evaluation of an Actuated MRI-Compatible Robotic System for MRI-Guided Prostate Intervention

    PubMed Central

    Krieger, Axel; Song, Sang-Eun; Cho, Nathan B.; Iordachita, Iulian; Guion, Peter; Fichtinger, Gabor; Whitcomb, Louis L.

    2012-01-01

    This paper reports the design, development, and magnetic resonance imaging (MRI) compatibility evaluation of an actuated transrectal prostate robot for MRI-guided needle intervention in the prostate. The robot performs actuated needle MRI-guidance with the goals of providing (i) MRI compatibility, (ii) MRI-guided needle placement with accuracy sufficient for targeting clinically significant prostate cancer foci, (iii) reducing interventional procedure times (thus increasing patient comfort and reducing opportunity for needle targeting error due to patient motion), (iv) enabling real-time MRI monitoring of interventional procedures, and (v) reducing the opportunities for error that arise in manually actuated needle placement. The design of the robot, employing piezo-ceramic-motor actuated needle guide positioning and manual needle insertion, is reported. Results of a MRI compatibility study show no reduction of MRI signal-to-noise-ratio (SNR) with the motors disabled. Enabling the motors reduces the SNR by 80% without RF shielding, but SNR is only reduced by 40% to 60% with RF shielding. The addition of radio-frequency shielding is shown to significantly reduce image SNR degradation caused by the presence of the robotic device. An accuracy study of MRI-guided biopsy needle placements in a prostate phantom is reported. The study shows an average in-plane targeting error of 2.4 mm with a maximum error of 3.7 mm. These data indicate the system’s needle targeting accuracy is similar to that obtained with a previously reported manually actuated system, and is sufficient to reliably sample clinically significant prostate cancer foci under MRI-guidance. PMID:23326181

  5. Clustered functional MRI of overt speech production.

    PubMed

    Sörös, Peter; Sokoloff, Lisa Guttman; Bose, Arpita; McIntosh, Anthony R; Graham, Simon J; Stuss, Donald T

    2006-08-01

    To investigate the neural network of overt speech production, event-related fMRI was performed in 9 young healthy adult volunteers. A clustered image acquisition technique was chosen to minimize speech-related movement artifacts. Functional images were acquired during the production of oral movements and of speech of increasing complexity (isolated vowel as well as monosyllabic and trisyllabic utterances). This imaging technique and behavioral task enabled depiction of the articulo-phonologic network of speech production from the supplementary motor area at the cranial end to the red nucleus at the caudal end. Speaking a single vowel and performing simple oral movements involved very similar activation of the cortical and subcortical motor systems. More complex, polysyllabic utterances were associated with additional activation in the bilateral cerebellum, reflecting increased demand on speech motor control, and additional activation in the bilateral temporal cortex, reflecting the stronger involvement of phonologic processing.

  6. Functional MRI in awake unrestrained dogs.

    PubMed

    Berns, Gregory S; Brooks, Andrew M; Spivak, Mark

    2012-01-01

    Because of dogs' prolonged evolution with humans, many of the canine cognitive skills are thought to represent a selection of traits that make dogs particularly sensitive to human cues. But how does the dog mind actually work? To develop a methodology to answer this question, we trained two dogs to remain motionless for the duration required to collect quality fMRI images by using positive reinforcement without sedation or physical restraints. The task was designed to determine which brain circuits differentially respond to human hand signals denoting the presence or absence of a food reward. Head motion within trials was less than 1 mm. Consistent with prior reinforcement learning literature, we observed caudate activation in both dogs in response to the hand signal denoting reward versus no-reward.

  7. MRI of paraganglioma of the filum terminale

    SciTech Connect

    Boncoeur-Martel, M.P.; Lesort, A.; Moreau, J.J.; Labrousse, F.; Roche, I.; Bouillet, P.; Pascaud, J.L.; Dupuy, J.P.

    1996-01-01

    Paragangliomas are benign tumors arising from paraganglionic cells of the sympathetic nervous system. They are of neuroectodermal derivation, with the majority occurring in the adrenal medulla. Extraadrenal locations are usually nonfunctioning and mostly observed (90%) in the head and neck region (carotid body or glomus jugulare tumors). Rare reported locations include the mediastinum, retroperitoneum, lungs, duodenum, and bladder. Within the CNS, paragangliomas have been observed in the pineal region, petrous ridge, sella turcica, and spinal canal. Paraganglioma of the cauda equina was first reported, but not recognized as such, in 1970. We know of 10 reports that describe MRI appearance. We present a new case and review the imaging findings of a paraganglioma of the filum terminale. 14 refs., 3 figs.

  8. NMR and MRI apparatus and method

    DOEpatents

    Clarke, John; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Myers, Whittier; McDermott, Robert; ten Haken, Bernard; Pines, Alexander; Trabesinger, Andreas

    2007-03-06

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. Additional signal to noise benefits are obtained by use of a low noise polarization coil, comprising litz wire or superconducting materials. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  9. Basic concepts of advanced MRI techniques.

    PubMed

    Pagani, Elisabetta; Bizzi, Alberto; Di Salle, Francesco; De Stefano, Nicola; Filippi, Massimo

    2008-10-01

    An overview is given of magnetic resonance (MR) techniques sensitized to diffusion, flow, magnetization transfer effect, and local field inhomogeneities induced by physiological changes, that can be viewed, in the clinical practice, as advanced because of their challenging implementation and interpretation. These techniques are known as diffusion-weighted, perfusion, magnetization transfer, functional MRI and MR spectroscopy. An important issue is that they can provide quantitative estimates of structural and functional characteristics that are below the voxel resolution. This review does not deal with the basic concepts of the MR physics and the description of the available acquisition and postprocessing methods, but hopefully provides an adequate background to readers and hence facilitate the understanding of the following clinical contributions.

  10. Precursors and Correlates of Anxiety Trajectories from Late Childhood to Late Adolescence

    ERIC Educational Resources Information Center

    Letcher, Primrose; Sanson, Ann; Smart, Diana; Toumbourou, John W.

    2012-01-01

    The present research employed a prospective, multi-informant design to examine precursors and correlates of differing anxiety profiles from late childhood to late adolescence. The sample consisted of 626 boys and 667 girls who are participants in the Australian Temperament Project, a large, longitudinal, community-based study that has followed…

  11. To see bruxism: a functional MRI study

    PubMed Central

    2015-01-01

    Objective: Since the pathophysiology of bruxism is not clearly understood, there exists no possible treatment. The aim of this study is to investigate the cerebral activation differences between healthy subjects and patients with bruxism on behalf of possible aetiological factors. Methods: 12 healthy subjects and 12 patients with bruxism, a total of 24 right-handed female subjects (aged 20–27 years) were examined using functional MRI during tooth-clenching and resting tasks. Imaging was performed with 3.0-T MRI scanner with a 32-channel head coil. Differences in regional brain activity between patients with bruxism and healthy subjects (control group) were observed with BrainVoyager QX 2.8 (Brain Innovation, Maastricht, Netherlands) statistical data analysis program. Activation maps were created using the general linear model: single study and multistudy multisubject for statistical group analysis. This protocol was approved by the ethics committee of medical faculty of Kirikkale University, Turkey (02/04), based on the guidelines set forth in the Declaration of Helsinki. Results: The group analysis revealed a statistically significant increase in blood oxygenation level-dependent signal of three clusters in the control group (p < 0.005), which may indicate brain regions related with somatognosis, repetitive passive motion, proprioception and tactile perception. These areas coincide with Brodmann areas 7, 31, 39 and 40. It is conceivable that there are differences between healthy subjects and patients with bruxism. Conclusions: Our findings indicate that there was a decrease of cortical activation pattern in patients with bruxism in clenching tasks. This indicates decreased blood flow and activation in regional neuronal activity. Bruxism, as an oral motor disorder concerns dentistry, neurology and psychiatry. These results might improve the understanding and physiological handling of sleep bruxism. PMID:25806864

  12. Novel approaches to low-cost MRI.

    PubMed

    Macovski, A; Conolly, S

    1993-08-01

    This paper presents a combination of speculative approaches, some related to earlier work and some apparently novel, which show great promise in providing a new class of MRI machines that would be considerably less expensive. This class would have advantages and disadvantages as compared to existing MRI, over and above that of low cost. The disadvantages include the apparent inability to perform classic spectroscopy, and limited flexibility in the area of selective excitation. The advantages include a fundamental immunity to inhomogeneity and susceptibility problems, the ability to create a wide class of machines that are designed for specific anatomy-related applications, the ability to design open machines for physician access, and improved capability for high speed imaging. Generic to all of the methods presented are a pulsed polarizing field and an oscillatory read-out bias field. The pulsed field initially polarizes the magnetic moments. Since it is not on during the readout operation it has negligible homogeneity requirements since changes in the field amplitude will merely shade the image intensity. During readout a relatively low bias field is used. To enable the use of a relatively inhomogeneous bias field, an oscillatory field is used that has a zero average value. This prevents any long-term buildup of phase errors due to a frequency error associated with inhomogeneity. Thus the average bias frequency will be determined solely by the frequency rather than the amplitude of the bias field. Three methods are described, all including the above features. The first two involve imaging in the laboratory frame, while the third involves imaging in the rotating frame. The second approach requires no RF excitation and the third approach uses RF bias and gradient signals. Some approaches to slice selection are described.

  13. Bayesian segmentation of brainstem structures in MRI.

    PubMed

    Iglesias, Juan Eugenio; Van Leemput, Koen; Bhatt, Priyanka; Casillas, Christen; Dutt, Shubir; Schuff, Norbert; Truran-Sacrey, Diana; Boxer, Adam; Fischl, Bruce

    2015-06-01

    In this paper we present a method to segment four brainstem structures (midbrain, pons, medulla oblongata and superior cerebellar peduncle) from 3D brain MRI scans. The segmentation method relies on a probabilistic atlas of the brainstem and its neighboring brain structures. To build the atlas, we combined a dataset of 39 scans with already existing manual delineations of the whole brainstem and a dataset of 10 scans in which the brainstem structures were manually labeled with a protocol that was specifically designed for this study. The resulting atlas can be used in a Bayesian framework to segment the brainstem structures in novel scans. Thanks to the generative nature of the scheme, the segmentation method is robust to changes in MRI contrast or acquisition hardware. Using cross validation, we show that the algorithm can segment the structures in previously unseen T1 and FLAIR scans with great accuracy (mean error under 1mm) and robustness (no failures in 383 scans including 168 AD cases). We also indirectly evaluate the algorithm with a experiment in which we study the atrophy of the brainstem in aging. The results show that, when used simultaneously, the volumes of the midbrain, pons and medulla are significantly more predictive of age than the volume of the entire brainstem, estimated as their sum. The results also demonstrate that the method can detect atrophy patterns in the brainstem structures that have been previously described in the literature. Finally, we demonstrate that the proposed algorithm is able to detect differential effects of AD on the brainstem structures. The method will be implemented as part of the popular neuroimaging package FreeSurfer.

  14. Quantitative Analysis of Vortical Blood Flow in the Thoracic Aorta Using 4D Phase Contrast MRI

    PubMed Central

    von Spiczak, Jochen; Crelier, Gerard; Giese, Daniel; Kozerke, Sebastian; Maintz, David; Bunck, Alexander Christian

    2015-01-01

    Introduction Phase contrast MRI allows for the examination of complex hemodynamics in the heart and adjacent great vessels. Vortex flow patterns seem to play an important role in certain vascular pathologies. We propose two- and three-dimensional metrics for the objective quantification of aortic vortex blood flow in 4D phase contrast MRI. Materials and Methods For two-dimensional vorticity assessment, a standardized set of 6 regions-of-interest (ROIs) was defined throughout the course of the aorta. For each ROI, a heatmap of time-resolved vorticity values ω→=∇v→ was computed. Evolution of minimum, maximum, and average values as well as opposing rotational flow components were analyzed. For three-dimensional analysis, vortex core detection was implemented combining the predictor-corrector method with λ2 correction. Strength, elongation, and radial expansion of the detected vortex core were recorded over time. All methods were applied to 4D flow MRI datasets of 9 healthy subjects, 2 patients with mildly dilated aorta, and 1 patient with aortic aneurysm. Results Vorticity quantification in the 6 standardized ROIs enabled the description of physiological vortex flow in the healthy aorta. Helical flow developed early in the ascending aorta (absolute vorticity = 166.4±86.4 s-1 at 12% of cardiac cycle) followed by maximum values in mid-systole in the aortic arch (240.1±45.2 s-1 at 16%). Strength, elongation, and radial expansion of 3D vortex cores escalated in early systole, reaching a peak in mid systole (strength = 241.2±30.7 s-1 at 17%, elongation = 65.1±34.6 mm at 18%, expansion = 80.1±48.8 mm2 at 20%), before all three parameters similarly decreased to overall low values in diastole. Flow patterns were considerably altered in patient data: Vortex flow developed late in mid/end-systole close to the aortic bulb and no physiological helix was found in the aortic arch. Conclusions We have introduced objective measures for quantification of vortical flow in

  15. Bilingual Cognitive Control in Language Switching: An fMRI Study of English-Chinese Late Bilinguals

    PubMed Central

    Ma, Hengfen; Hu, Jiehui; Xi, Jie; Shen, Wen; Ge, Jianqiao; Geng, Feng; Wu, Yuntao; Guo, Jinjin; Yao, Dezhong

    2014-01-01

    The present study explored the bilingual cognitive control mechanism by comparing Chinese-English bilinguals’ language switching in a blocked picture naming paradigm against three baseline conditions, namely the control condition (a fixation cross, low-level baseline), single L1 production (Chinese naming, high-level baseline), and single L2 production (English naming, high-level baseline). Different activation patterns were observed for language switching against different baseline conditions. These results indicate that different script bilingual language control involves a fronto-parietal-subcortical network that extends to the precentral gyrus, the Supplementary Motor Area, the Supra Marginal Gyrus, and the fusiform. The different neural correlates identified across different comparisons supported that bilingual language switching involves high-level cognitive processes that are not specific to language processing. Future studies adopting a network approach are crucial in identifying the functional connectivity among regions subserving language control. PMID:25180974

  16. Relation of Childhood Home Environment to Cortical Thickness in Late Adolescence: Specificity of Experience and Timing

    PubMed Central

    Avants, Brian B.; Hackman, Daniel A.; Betancourt, Laura M.; Lawson, Gwendolyn M.; Hurt, Hallam; Farah, Martha J.

    2015-01-01

    What are the long-term effects of childhood experience on brain development? Research with animals shows that the quality of environmental stimulation and parental nurturance both play important roles in shaping lifelong brain structure and function. Human research has so far been limited to the effects of abnormal experience and pathological development. Using a unique longitudinal dataset of in-home measures of childhood experience at ages 4 and 8 and MRI acquired in late adolescence, we were able to relate normal variation in childhood experience to later life cortical thickness. Environmental stimulation at age 4 predicted cortical thickness in a set of automatically derived regions in temporal and prefrontal cortex. In contrast, age 8 experience was not predictive. Parental nurturance was not predictive at either age. This work reveals an association between childhood experience and later brain structure that is specific relative to aspects of experience, regions of brain, and timing. PMID:26509809

  17. Behavioral and anatomical consequences of early versus late symbol training in macaques

    PubMed Central

    Srihasam, Krishna; Mandeville, Joseph B.; Morocz, Istvan A.; Sullivan, Kevin J.; Livingstone, Margaret S.

    2012-01-01

    Distinct brain regions, reproducible from one person to the next, are specialized for processing different kinds of human expertise, such as face recognition and reading. Here we explore the relationship between age of learning, learning ability, and specialized brain structures. Specifically we ask whether the existence of reproducible cortical domains necessarily means that certain abilities are innate, or innately easily learned, or whether reproducible domains can be formed, or refined, by interactions between genetic programs and common early experience. Functional MRI showed that intensive early, but not late, experience caused the formation of category-selective regions in macaque temporal lobe for stimuli never naturally encountered by monkeys. And behaviorally, early training produced more fluent processing of these stimuli than the same training in adults. One explanation for these results is that in higher cortical areas, as in early sensory areas, experience drives functional clustering and functional clustering determines how that information is processed. PMID:22325210

  18. Fusion of PET and MRI for Hybrid Imaging

    NASA Astrophysics Data System (ADS)

    Cho, Zang-Hee; Son, Young-Don; Kim, Young-Bo; Yoo, Seung-Schik

    Recently, the development of the fusion PET-MRI system has been actively studied to meet the increasing demand for integrated molecular and anatomical imaging. MRI can provide detailed anatomical information on the brain, such as the locations of gray and white matter, blood vessels, axonal tracts with high resolution, while PET can measure molecular and genetic information, such as glucose metabolism, neurotransmitter-neuroreceptor binding and affinity, protein-protein interactions, and gene trafficking among biological tissues. State-of-the-art MRI systems, such as the 7.0 T whole-body MRI, now can visualize super-fine structures including neuronal bundles in the pons, fine blood vessels (such as lenticulostriate arteries) without invasive contrast agents, in vivo hippocampal substructures, and substantia nigra with excellent image contrast. High-resolution PET, known as High-Resolution Research Tomograph (HRRT), is a brain-dedicated system capable of imaging minute changes of chemicals, such as neurotransmitters and -receptors, with high spatial resolution and sensitivity. The synergistic power of the two, i.e., ultra high-resolution anatomical information offered by a 7.0 T MRI system combined with the high-sensitivity molecular information offered by HRRT-PET, will significantly elevate the level of our current understanding of the human brain, one of the most delicate, complex, and mysterious biological organs. This chapter introduces MRI, PET, and PET-MRI fusion system, and its algorithms are discussed in detail.

  19. Polymeric (1) H MRI Probes for Visualizing Tumor In Vivo.

    PubMed

    Kondo, Teruyuki; Kimura, Yu; Yamada, Hisatsugu; Aoyama, Yasuhiro

    2017-04-07

    Magnetic resonance imaging (MRI) has become a prominent non- or low-invasive imaging technique, providing high-resolution, three-dimensional images as well as physiological information about tissues. Low-molecular-weight Gd-MRI contrast agents (CAs), such as Gd-DTPA (DTPA: diethylenetriaminepentaacetic acid), are commonly used in the clinical diagnosis, while macromolecular Gd-MRI CAs have several advantages over low-molecular-weight Gd-MRI CAs, which help minimize the dose of CAs and the risk of side effects. Accordingly, we developed chiral dendrimer Gd-MRI CAs, which showed high r1 values. The association constant values (Ka ) of S-isomeric dendrimer CAs to bovine serum albumin (BSA) were higher than those of R-isomeric dendrimer CAs. Besides, based on a totally new concept, we developed (13) C/(15) N-enriched multiple-resonance NMR/MRI probes, which realized highly selective observation of the probes and analysis of metabolic reactions of interest. This account summarizes our recent study on developing both chiral dendrimer Gd-MRI CAs, and self-traceable (13) C/(15) N-enriched phosphorylcholine polymer probes for early detection of tumors.

  20. Leg muscle involvement in facioscapulohumeral muscular dystrophy assessed by MRI.

    PubMed

    Olsen, David B; Gideon, Peter; Jeppesen, Tina Dysgaard; Vissing, John

    2006-11-01

    Using MRI, we evaluated the degree of involvement of muscles in the lower extremities of 18 unselected patients with facioscapulohumeral muscular dystrophy (FSHD). Findings were correlated with fragment size of the mutated gene, age, disease duration and muscle power. Most affected muscles were the hamstrings followed by the tibialis anterior and the medial gastrocnemius. The vastus-, gluteal- and peroneal muscles were the most unaffected, and the psoas muscle did not show evidence of involvement in any of the investigated subjects. Asymmetric involvement was evident in 15% of the investigated muscles on MRI and 6% on manual muscle strength testing. MRI findings in muscle tended to correlate with disease duration (r = 0.49; p < 0.05), but not with gene fragment size or age. MRI disclosed involvement of muscles performing hip flexion and ankle dorsal flexion that could not be detected by manual muscle strength testing. Otherwise, there was a close correlation (approximately r = 0.75; p < 0.0001) between muscle strength and MRI severity score for other muscle groups. The present study shows that MRI may disclose muscle involvement in FSHD that is not apparent on manual muscle testing, and suggests that MRI of muscle may be an important assessment tool in clinical trials involving patients with FSHD.