bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of single injection liver arterial phase gadolinium enhanced MRI using bolus track real‐time imaging
Authors: Sharma Puneet , Kalb Bobby , Kitajima Hiroumi D. , Salman Khalil N. , Burrow Bobbie , Ray Gaye L. , Martin Diego R. 
Published: December 2010

AbstractPurpose:To measure contrast agent enhancement kinetics in the liver and to further evaluate and develop an optimized gadolinium enhanced MRI using a single injection real‐time bolus‐tracking method for reproducible imaging of the transient arterial‐phase.Materials and Methods:A total of 18 subjects with hypervascular liver lesions were imaged with four dimensional (4D) perfusion scans to measure time‐to‐peak (TTP) delays of arterial (aorta‐celiac axis), liver parenchyma, liver lesion, portal, and hepatic veins. Time delays were calculated from the TTP‐aorta signal, and then related to the gradient echo (GRE) k‐space acquisition design, to determine optimized timing for real‐time bolus‐track triggering methodology. As another measure of significance, 200 clinical patients were imaged with 3D‐GRE using either a fixed time‐interval or by individualized arterial bolus real‐time triggering. Bolus TTP‐aorta was calculated and arterial‐phase acquisitions were compared for accuracy and reproducibility using specific vascular enhancement indicators.Results:The mean bolus transit‐time to peak‐lesion contrast was 8.1 ± 2.7 seconds following arterial detection, compared to 32.1 ± 5.4 seconds from contrast injection, representing a 62.1% reduction in the time‐variability among subjects (N = 18). The real‐time bolus‐triggered technique more consistently captured the targeted arterial phase (94%), compared to the fixed timing technique (73%), representing an expected improvement of timing accuracy in 28% of patients (P = 0.0001389).Conclusion:Our results show detailed timing window analysis required for optimized arterial real‐time bolus‐triggering acquisition of transient arterial phase features of liver lesions, with optimized arterial triggering expected to improve reproducibility in a significant number of patients. J. Magn. Reson. Imaging 2011;33:110–118. © 2010 Wiley‐Liss, Inc.
Relationship between sodium intensity and perfusion deficits in acute ischemic stroke
Authors: Tsang Adrian , Stobbe Robert W. , Asdaghi Negar , Hussain Muhammad S. , Bhagat Yusuf A. , Beaulieu Christian , Emery Derek , Butcher Ken S. 
Published: December 2010

AbstractPurposeTo assess the relationship between sodium signal intensity changes and oligemia, measured with perfusion‐weighted imaging (PWI), in ischemic stroke patients.Materials and MethodsNine ischemic stroke patients (55 ± 13 years), four with follow‐up scans, underwent sodium and proton imaging 4–32 hours after symptom onset. Relative sodium intensity was calculated as the ratio of signal intensities in core (identified as hypertintense lesions on diffusion‐weighted imaging [DWI]) or putative penumbra (PWI‐DWI mismatch) to contralateral homologous regions.ResultsSodium intensity increases in the core were not correlated with the severity of hypoperfusion, measured with either cerebral blood flow (rho = 0.157; P = 0.61) or cerebral blood volume (rho = −0.234; P = 0.44). In contrast, relative sodium intensity was not elevated (4–7 hours 0.96 ± 0.07; 17–32 hours 1.00 ± 0.07) in PWI‐DWI mismatch regions.ConclusionSodium signal intensity cannot be predicted by the degree of hypoperfusion acutely. Sodium intensity also remains unchanged in PWI‐DWI mismatch tissue, indicating preservation of ionic homeostasis. Sodium magnetic resonance imaging (MRI), in conjunction with PWI and DWI, may permit identification of patients with viable tissue, despite an unknown symptom onset time. J. Magn. Reson. Imaging 2011;33:41–47. © 2010 Wiley‐Liss, Inc.
Glenohumeral joint instability
Authors: Omoumi Patrick , Teixeira Pedro , Lecouvet Frédéric , Chung Christine B. 
Published: December 2010

AbstractDue to the configuration of its bony elements, the glenohumeral joint is the most mobile joint of the body, but also an inherently unstable articulation. Stabilization of the joint is linked to a complex balance between static and dynamic soft tissue stabilizers. Because of complex biomechanics, and the existence of numerous classifications and acronyms to describe shoulder instability lesions, this remains a daunting topic for most radiologists. In this article we provide a brief review of the anatomy of the glenohumeral joint, as well as the classifications and the pathogenesis of shoulder instability. Technical aspects related to the available imaging techniques (including computed tomography [CT] arthrography, magnetic resonance imaging [MRI], and MR arthrography) are reviewed. We then describe the imaging findings related to shoulder instability, focusing on those elements that are important to the clinician. J. Magn. Reson. Imaging 2011;33:2–16. © 2010 Wiley‐Liss, Inc.
Effects of postprandial state and mesenteric blood flow on the repeatability of MR elastography in asymptomatic subjects
Authors: Hines Catherine D.G. , Lindstrom Mary J. , Varma Adarsh K. , Reeder Scott B. 
Published: December 2010

AbstractPurposeTo determine the repeatability of stiffness measurements in the liver using MR elastography (MRE) during the fasted and fed states. MRE has gained increased recognition as a noninvasive method to quantify fibrotic changes in the liver. It is well known that eating increases splanchnic blood flow, and fasting status of patients has been recognized as a factor that may affect hepatic stiffness measured with MRE.Materials and MethodsHepatic MRE stiffness and flow through the superior mesenteric vein (SMV) were measured in 12 healthy subjects in fasted and fed states, and measurements were repeated 5 weeks later. A linear mixed effects model was used to estimate the sources of variability in the data, which included day (exams on different days) and subject. Sources were combined to calculate the overall standard deviation of a single MRE measurement.ResultsThe total within‐subject standard deviation of an MRE exam is 8.5% (standard error [SE] = 1.7%) or 9.0% (SE = 1.8%) for fasted and fed states, respectively. No significant differences between fasted/fed state stiffness and no correlation between hepatic stiffness and SMV flow were observed.ConclusionAs seen in this smaller population, healthy subjects scanned in a known fasted or fed state provide repeatable stiffness estimates with no relationship to SMV flow. J. Magn. Reson. Imaging 2011;33:239–244. © 2010 Wiley‐Liss, Inc.
Mapping developmental precentral and postcentral gyral changes in children on magnetic resonance images
Authors: Yang Faguo , Shan Zuyao Y. 
Published: December 2010

AbstractPurposeTo study the shape changes in precentral gyrus (PRG) and postcentral gyrus (PCG) during healthy brain development in childhood.Materials and MethodsMagnetic resonance (MR) images from 20 healthy children scanned twice at 6.3 ± 0.8 and 8.1 ± 0.9 years old were analyzed in this study. The analysis steps included: 1) The PRG and PCG were manually segmented from the MR images of each subject; 2) 3D mesh representing the PRG and PCG were built from the manually segmented images; 3) a series of shape description features were extracted and statistically analyzed by a permutation test method.ResultsThis study showed the following statistically significant findings (P < 0.05): left PCG and PRG are located more posteriorly and superiorly than their right compartments; the hemispheric asymmetry of the PRG in the inferior–superior direction decreased after 2 years; the superior part of the PCG and PRG shifted and rotated to the posterior side of the brain.ConclusionDuring normal pediatric brain development hemispheric asymmetry and shape of PCG and PRG are changed. These findings, together with previous reports in the literature, illustrate a region‐specific brain structure maturation pattern in children and may be related to changing neurocognitive functions. J. Magn. Reson. Imaging 2011;33:62–70. © 2010 Wiley‐Liss, Inc.
Reliability of two techniques for assessing cerebral iron deposits with structural magnetic resonance imaging
Authors: Valdés Hernández Maria C. , Jeong Tina H. , Murray Catherine , Bastin Mark E. , Chappell Francesca M. , Deary Ian J. , Wardlaw Joanna M. 
Published: December 2010

AbstractPurposeTo test the reliability of two computational methods for segmenting cerebral iron deposits (IDs) in the aging brain, given that its measurement in magnetic resonance imaging (MRI) is challenging due to the similar effect produced by other minerals, especially calcium, on T2*‐weighted sequences.Materials and MethodsT1‐, T2*‐weighted, and fluid‐attenuated inversion recovery (FLAIR) MR brain images obtained at 1.5T from 70 subjects in their early 70s who displayed a wide range of brain IDs were analyzed. The first segmentation method used a multispectral approach based on the fusion of two or more structural sequences registered and mapped in the red/green color space followed by Minimum Variance Quantization. The second method employed a combined thresholding, size and shape analysis using T2*‐weighted images augmented with visual information from T1‐weighted data.ResultsBoth segmentation techniques had high intra‐ and interobserver agreement (95% confidence interval [CI] = ± 57 voxels in a range from 0 to 1800), which decreased in subjects with significant microbleeds and/or IDs. However, the thresholding method was more observer dependent in identifying microbleeds and IDs boundaries than the multispectral approach.ConclusionBoth techniques proved to be in agreement and have good intra‐ and interobserver reliability. However, they have limitations, specifically with regard to automation and observer independence, so further work is required to develop fully user‐independent methods of identifying cerebral IDs. J. Magn. Reson. Imaging 2011;33:54–61. © 2010 Wiley‐Liss, Inc.
Cardiac MRI to investigate myocardial scar and coronary venous anatomy using a slow infusion of dimeglumine gadobenate in patients undergoing assessment for cardiac resynchronization therapy
Authors: Duckett Simon G. , Chiribiri Amedeo , Ginks Matthew R. , Sinclair Stephen , Knowles Benjamin R. , Botnar Rene , Carr‐White Gerry S. , Rinaldi Christopher A. , Nagel Eike , Razavi Reza , Schaeffter Tobias 
Published: December 2010

AbstractPurposeTo evaluate a cardiac MR (CMR) examination with slow infusion of a high‐relaxivity contrast agent to visualize coronary venous anatomy (CVA) and myocardial scar in heart failure patients awaiting cardiac resynchronization therapy (CRT).Materials and MethodsFourteen patients awaiting CRT (seven ischemic cardiomyopathy (ICM) and seven non‐ICM) and two with normal LV function underwent CMR on a 1.5 Tesla (T) MR scanner. Dimeglumine‐gadobenate was slowly infused. Bolus arrival in the LV was measured by a dynamic electrocardiogram (ECG) ‐triggered inversion recovery (IR) scan subsequent to starting an ECG‐triggered respiratory‐navigated three‐dimensional (3D) SSFP MR scan with IR preparation to acquire systolic whole‐heart anatomy for vein visualization. Delayed contrast‐enhanced MR scan was performed to assess myocardial scar. CVA obtained by CMR was compared with X‐ray venography in 11 patients. CVA and scar were segmented and registered for visual inspection.ResultsFor all subjects, there was excellent visualization of the CVA. All ICM and one non‐ICM patient showed scar. There was excellent correlation between veins seen by CMR and venography.ConclusionWe have demonstrated that slow infusion protocol of dimeglumine‐gadobenate can be used to assess both CVA and myocardial scar in a single MR examination. Furthermore, an image overlay technique has been used to show the relationship of scar to the CVA. J. Magn. Reson. Imaging 2011;33:87–95. © 2010 Wiley‐Liss, Inc.
Dynamic contrast‐enhanced magnetic resonance imaging and invasive breast cancer: Primary lesion kinetics correlated with axillary lymph node extracapsular extension
Authors: Loiselle Christopher R. , Eby Peter R. , Peacock Sue , Kim Janice N. , Lehman Constance D. 
Published: December 2010

AbstractPurposeTo determine if dynamic contrast‐enhanced (DCE) magnetic resonance imaging (MRI) peak enhancement (PE) of primary breast cancer can predict the presence of lymph node extracapsular extension (LNECE) in patients with axillary metastatic disease.Materials and MethodsIn all, 167 patients treated with radiotherapy for invasive breast cancer from January 1, 2006 to November 1, 2007 were retrospectively identified. Patients with DCE‐MRI and surgical axillary staging were included in this study. PE of primary tumors was compared according to axillary nodal status: negative, positive without LNECE, or positive with LNECE. A receiver operator characteristic curve (ROC) was plotted to determine accuracy of PE to predict LNECE.ResultsForty‐six patients met the study criteria. Thirty‐two (70%) were node‐negative, 9 (19%) were node‐positive without LNECE, and 5 (11%) were node‐positive with LNECE. PE was greater for patients with LNECE (mean 365%) compared to node‐positive patients without LNECE (mean 183%) P = 0.05 and node‐negative patients (mean 144%) P = 0.0012. Area under the ROC curve was 0.93.ConclusionDCE‐MRI PE may be a surrogate marker for LNECE. If validated, DCE‐MRI may provide noninvasive kinetic information informing axillary nodal status for patients who receive chemotherapy prior to surgical axillary staging or forego axillary dissection after a positive sentinel node biopsy. J. Magn. Reson. Imaging 2011;33:96–101. © 2010 Wiley‐Liss, Inc.
Liver methylene fraction by dual‐ and triple‐echo gradient‐echo imaging at 3.0T: Correlation with proton MR spectroscopy and estimation of robustness after SPIO administration
Authors: Guiu Boris , Petit Jean‐Michel , Loffroy Romaric , Aho Serge , Ben Salem Douraied , Masson David , Robin Isabelle , Vergès Bruno , Hillon Patrick , Cercueil Jean‐Pierre , Krausé Denis 
Published: December 2010

AbstractPurposeTo assess the systematic errors in liver methylene fraction (LMF) resulting from fat–fat interference effects with dual‐ and triple‐echo gradient‐recalled‐echo Dual/Triple GRE) sequences and to test the robustness of these sequences after iron overloading.Materials and MethodsForty type‐2 diabetic patients underwent LMF measurement by 3.0T 1H magnetic resonance spectroscopy (corrected for T1 and T2 decays) as the reference standard and liver fat fraction (%Fat) measurement by four Dual/Triple GRE sequences with 20° and 60° flip angle (α), corrected for T1 recovery. The same four sequences were repeated in eight patients after ferumoxide injection. Corrections for systematic errors were determined from the linear regressions (spectroscopy LMF values over Dual/Triple GRE %Fat values). Robustness was tested using Wilcoxon's signed‐rank test.ResultsFat–fat interference effects produced a ∼10% relative systematic error and T2* decay produced a 1.9%–4.2% absolute systematic error in LMF. When comparing before and after ferumoxide, dual‐echo imaging with α = 20° and α = 60°, even when corrected, showed absolute differences of 7.23% [2.81%–10.25%] (P = 0.0117) and 5.65% [1.89%–8.216.8%] (P = 0.0117), respectively; compared to only 1.17% [0.08%–2.83%] (P = 0.0251) and 1.15% [0.37%–2.73%] (P = 0.2626) with triple‐echo imaging and α = 20° and α = 60°, respectively.ConclusionTriple‐echo imaging with α = 60° corrected for both T1 recovery and fat–fat interference effects is robust after superparamagnetic iron oxide (SPIO) administration and can reliably quantify LMF. J. Magn. Reson. Imaging 2011;33:119–127. © 2010 Wiley‐Liss, Inc.
Increased gray matter volume of left pars opercularis in male orchestral musicians correlate positively with years of musical performance
Authors: Abdul‐Kareem Ihssan A. , Stancak Andrej , Parkes Laura M. , Sluming Vanessa 
Published: December 2010

AbstractPurposeTo compare manual volumetry of gray matter (GM) / white matter (WM) of Broca's area subparts: pars opercularis (POP) and pars triangularis (PTR) in both hemispheres between musicians and nonmusician, as it has been shown that these regions are crucial for musical abilities. A previous voxel‐based morphometric (VBM) study conducted in our laboratory reported increased GM density in Broca's area of left hemisphere in male orchestral musicians. Functional segregation of POP/PTR justified separate volumetric analysis of these parts.Materials and MethodsWe used the same cohort for the VBM study. Manual morphometry (stereology) was used to compare volumes between 26/26 right‐handed orchestral musicians/nonmusicians.ResultsAs expected, musicians showed significantly increased GM volume in the Broca's area, specifically in the left POP. No significant results were detected in right POP, left/right PTR GM volumes, and WM volumes for all regions. Results were positively correlated with years of musical performance (r = 0.7, P = 0.0001).ConclusionThis result corroborates the VBM study and is in line with the hypothesis of critical involvement of POP in hearing‐action integration being an integral component of frontoparietotemporal mirror neuron network. We hypothesize that increased size of musicians' left POP represent use‐dependent structural adaptation in response to intensive audiomotor skill acquisition. J. Magn. Reson. Imaging 2011;33:24–32. © 2010 Wiley‐Liss, Inc.
Divergent neural processes specific to the acute and sustained phases of verum and SHAM acupuncture
Authors: Liu Jixin , Qin Wei , Guo Qian , Sun Jinbo , Yuan Kai , Dong Minghao , Liu Peng , Zhang Yi , von Deneen Karen M. , Liu Yijun , Tian Jie 
Published: December 2010

AbstractPurposeTo discuss which brain region potentially functioned and switched between the immediate and delayed response of acupuncture.Materials and MethodsA nonrepeated event‐related functional MRI (fMRI) design was used to investigate the spatial and temporal patterns of acupuncture effects induced by needling an acupoint ST36 (ACU) and a nonmeridian point (SHAM). The standard general linear model was used to detect the immediate neural responses of acupuncture. Graph theory analysis was used to characterize the functional integrated network of the acupuncture delayed effect.ResultsAcupuncture induced significant signal changes in the limbic/paralimbic areas, neocortical regions, brainstem, and cerebellum for immediate effect both in ACU and SHAM. Some of these brain regions showed strong functional connectivity for a delayed effect in ACU. Conjunction analysis showed that the insula played a critical role during the overall process of ACU. No overlapping brain regions were found in SHAM.ConclusionThe findings of this study suggested that the delayed effects may reflect a more significant characteristic underlying acupuncture. Given that the insula as a relay station switched between the immediate and delayed response, it suggested that divergent functional connectivity patterns may mediate the acupuncture‐related effects for ACU and SHAM. J. Magn. Reson. Imaging 2011;33:33–40. © 2010 Wiley‐Liss, Inc.
Diffusion‐weighted imaging of the abdomen at 3.0 Tesla: Image quality and apparent diffusion coefficient reproducibility compared with 1.5 Tesla
Authors: Rosenkrantz Andrew B. , Oei Marcel , Babb James S. , Niver Benjamin E. , Taouli Bachir 
Published: December 2010

AbstractPurposeTo compare single‐shot echo‐planar imaging (SS EPI) diffusion‐weighted MRI (DWI) of abdominal organs between 1.5 Tesla (T) and 3.0T in healthy volunteers in terms of image quality, apparent diffusion coefficient (ADC) values, and ADC reproducibility.Materials and MethodsEight healthy volunteers were prospectively imaged in this HIPAA‐compliant IRB‐approved study. Each subject underwent two consecutive scans at both 1.5 and 3.0T, which included breathhold and free‐breathing DWI using a wide range of b‐values (0 to 800 s/mm2). A blinded observer rated subjective image quality (maximum score= 8), and a separate observer placed regions of interest within the liver, renal cortices, pancreas, and spleen to measure ADC at each field strength. Paired Wilcoxon tests were used to compare abdominal DWI between 1.5T and 3.0T for specific combinations of organs, b‐values, and acquisition techniques.ResultsSubjective image quality was significantly lower at 3.0T for all comparisons (P = 0.0078– 0.0156). ADC values were similar at 1.5T and 3.0T for all assessed organs, except for lower liver ADC at 3.0T using b0‐500‐600 and breathhold technique. ADC reproducibility was moderate at both 1.5T and 3.0T, with no significant difference in coefficient of variation of ADC between field strengths.ConclusionCompared with 1.5T, SS EPI at 3.0T provided generally similar ADC values, however, with worse image quality. Further optimization of abdominal DWI at 3.0T is needed. J. Magn. Reson. Imaging 2011;33:128–135. © 2010 Wiley‐Liss, Inc.
Low‐dose 3D time‐resolved magnetic resonance angiography (MRA) of the supraaortic arteries: Correlation with high spatial resolution 3D contrast‐enhanced MRA
Authors: Lee Youn‐Joo , Laub Gerhard , Jung So‐Lyung , Yoo Won‐Jong , Kim Young‐Joo , Ahn Kook‐Jin , Kim Bum‐soo 
Published: December 2010

AbstractPurposeTo evaluate the feasibility of low‐dose, 3D time‐resolved contrast‐enhanced magnetic resonance angiography (TR‐CEMRA) in the assessment of the supraaortic vessel, and to compare the results with high‐resolution contrast‐enhanced MRA (HR‐CEMRA).Materials and MethodsThis was an Institutional Review Board‐approved retrospective study. Forty‐five consecutive patients underwent contrast‐enhanced 3D TR‐CEMRA and 3D HR‐CEMRA for evaluation of neurovascular disease at 3.0 T. Gadobutrol was administered at a constant dose of 1 mL for TR‐CEMRA (independent of patient weight), and 0.1 mmol/kg for HR‐CEMRA. Two readers evaluated image quality using a four‐point scale (from 0 = excellent to 3 = nondiagnostic), and subsequently graded each stenosis into clinically relevant categories: normal (0%), mild stenosis (<50%), moderate to severe (>50%), and occlusion.ResultsThe overall image quality for low‐dose TR‐CEMRA was in the diagnostic range (median 0, range 0–3). On the grading of stenosis, TR‐CEMRA using the TWIST sequence correlated with HR‐CEMRA (r = 0.668, P < 0.001). In terms of the comparison of TR‐CEMRA with HR‐CEMRA, of the 675 supraaortic arterial segments evaluated for stenosis or occlusion, agreement occurred in 611 of 675 (90.5%), overestimation in 41 of 675 (6.1%), and underestimation 23 of 675 (3.4%).ConclusionTR‐CEMRA achieved by administration of a small contrast dose (1 cc) yields rapid and important functional and anatomical information in the evaluation of supraaortic arteries. Due to limited spatial resolution, TR‐CEMRA at the current parameters has a tendency to overestimate the stenosis of smaller intracranial arteries compared to HR‐CEMRA. J. Magn. Reson. Imaging 2011;33:71–76. © 2010 Wiley‐Liss, Inc.