Bolan P.J.,University of Minnesota |
Bolan P.J.,Center for Magnetic Resonance Research |
Arentsen L.,University of Minnesota |
Sueblinvong T.,University of Minnesota |
And 8 more authors.
Journal of Magnetic Resonance Imaging | Year: 2013
Purpose: To assess the feasibility of using fat-fraction imaging for measuring marrow composition changes over large regions in patients undergoing cancer therapy. Materials and Methods: Thirteen women with gynecologic malignancies who were to receive radiation and/or chemotherapy were recruited for this study. Subjects were imaged on a 3T magnetic resonance (MR) scanner at baseline (after surgery but before radiation or chemotherapy), 6 months, and 12 months after treatment. Water-fat imaging was used to generate high-resolution, 3D signal fat fraction (sFF) maps extending from mid-femur to L3. Treatment changes were assessed by measuring marrow sFF in the L4 vertebra, femoral necks, and control tissues. Results: Pretreatment and 6-month scans were compared in nine women. sFF increased significantly in both the L4 vertebral marrow (P = 0.04) and the femoral necks (P = 0.03), while no significant change was observed in control regions. Qualitatively, chemotherapy changes were more uniform in space, whereas the radiation-induced changes were largest in marrow regions inside and close to the target radiation field. Conclusion: Water-fat MRI is sensitive to changes in red/yellow marrow composition, and can be used for quantitative and qualitative assessment of treatment-induced marrow damage. © 2013 Wiley Periodicals, Inc. Source
Caruyer E.,French Institute for Research in Computer Science and Automation |
Aganj I.,University of Minnesota |
Lenglet C.,University of Minnesota |
Lenglet C.,Center for Magnetic Resonance Research |
And 2 more authors.
Proceedings - International Symposium on Biomedical Imaging | Year: 2011
The orientation distribution function (ODF) can be reconstructed online incrementally from diffusion-weighted MRI with a Kalman filtering framework. This online reconstruction can provide real-time feedback to the practitioner, especially appreciated for long acquisition protocols typical in Q-ball imaging. On top of the Kalman filter, we propose a method to evaluate online the reconstruction accuracy of the estimated ODF in constant solid angle. In addition, monitoring the residuals of the Kalman filter, we design, based on statistical tests, two algorithms for online detection of subject motion. The proposed techniques, tested on real and synthetic data under various experimental conditions, can detect rotation by angle less than 3. © 2011 IEEE. Source
Xiong Q.,Cardiovascular Division |
Xiong Q.,Center for Magnetic Resonance Research |
Ye L.,Cardiovascular Division |
Zhang P.,Cardiovascular Division |
And 10 more authors.
Circulation | Year: 2013
Background-: The use of cells derived from human induced pluripotent stem cells as cellular therapy for myocardial injury has yet to be examined in a large-animal model. Methods and Results-: Immunosuppressed Yorkshire pigs were assigned to 1 of 3 groups: A myocardial infarction group (MI group; distal left anterior descending coronary artery ligation and reperfusion; n=13); a cell-treatment group (MI with 4×10 vascular cells derived from human induced pluripotent stem cells administered via a fibrin patch; n=14); and a normal group (n=15). At 4 weeks, left ventricular structural and functional abnormalities were less pronounced in hearts in the cell-treated group than in MI hearts (P<0.05), and these improvements were accompanied by declines in scar size (10.4±1.6% versus 8.3±1.1%, MI versus cell-treatment group, P<0.05). The cell-treated group displayed a significant increase in vascular density and blood flow (0.83±0.11 and 1.05±0.13 mL·min·g, MI versus cell-treatment group, P<0.05) in the periscar border zone (BZ), which was accompanied by improvements in systolic thickening fractions (infarct zone,-10±7% versus 5±5%; BZ, 7±4% versus 23±6%; P<0.05). Transplantation of vascular cells derived from human induced pluripotent stem cells stimulated c-kit cell recruitment to BZ and the rate of bromodeoxyuridine incorporation in both c-kit cells and cardiomyocytes (P<0.05). Using a magnetic resonance spectroscopic saturation transfer technique, we found that the rate of ATP hydrolysis in BZ of MI hearts was severely reduced, and the severity of this reduction was linearly related to the severity of the elevations of wall stresses (r=0.82, P<0.05). This decline in BZ ATP utilization was markedly attenuated in the cell-treatment group. Conclusions-: Transplantation of vascular cells derived from human induced pluripotent stem cells mobilized endogenous progenitor cells into the BZ, attenuated regional wall stress, stimulated neovascularization, and improved BZ perfusion, which in turn resulted in marked increases in BZ contractile function and ATP turnover rate. © 2013 American Heart Association, Inc. Source
White T.,University of Minnesota |
White T.,Center for Magnetic Resonance Research |
White T.,Erasmus University Rotterdam |
Magnotta V.A.,University of Iowa |
And 19 more authors.
Schizophrenia Bulletin | Year: 2011
Background: Emerging evidence implicates white matter (WM) abnormalities in the pathophysiology of schizophrenia. However, there is considerable heterogeneity in the presentation of WM abnormalities in the existing studies. The object of this study was to evaluate WM integrity in a large sample of patients with first-episode (FE) and chronic schizophrenia in comparison to matched control groups. Our goal was to assess whether WM findings occurred early in the illness or whether these abnormalities developed with the illness over time. Methods: Participants included 114 patients with schizophrenia (31 FE and 83 chronic patients) and 138 matched controls. High-resolution structural and diffusion tensor images were obtained on all participants. Measures of fractional anisotropy (FA) were calculated for the 4 cortical lobes and the cerebellum and brain stem. Results: FA was significant lower in patients vs controls in the whole brain and individually in the frontal, parietal, occipital, and temporal lobes. FA was not significantly different in the brain stem or cerebellum. FA differences were significant only in patients with chronic schizophrenia and not in the FE group. Conclusions: We found global differences in the WM microstructure in patients with chronic but not FE schizophrenia. These findings suggest progressive alterations in WM microstructure. © 2010 The Author. Source
Xiong Q.,Center for Magnetic Resonance Research |
Du F.,Center for Magnetic Resonance Research |
Du F.,University of Minnesota |
Du F.,Harvard University |
And 11 more authors.
Circulation Research | Year: 2011
Rationale: 31P magnetization saturation transfer (MST) experiment is the most widely used method to study ATP metabolism kinetics. However, its lengthy data acquisition time greatly limits the wide biomedical applications in vivo, especially for studies requiring high spatial and temporal resolutions. Objective: We aimed to develop a novel superfast MST method that can accurately quantify ATP production rate constants (kf) through creatine kinase (CK) or ATP synthase (ATPase) with 2 spectra. Methods and Results: The T1nom (T1 nominal) method uses a correction factor to compensate the partially relaxed MST experiments, thus allowing measurement of enzyme kinetics with an arbitrary repetition time and flip angle, which consequently reduces the data acquisition time of a transmurally differentiated CK kf measurement by 91% as compared with the conventional method with spatial localization. The novel T1 method is validated theoretically with numeric simulation, and further verified with in vivo swine hearts, as well as CK and ATPase activities in rat brain at 9.4 Tesla. Importantly, the in vivo data from swine hearts demonstrate, for the first time, that within an observation window of 30 minutes, the inhibition of CK activity by iodoacetamide does not limit left ventricular chamber contractile function. Conclusions: A novel MST method for superfast examination of enzyme kinetics in vivo has been developed and verified theoretically and experimentally. In the in vivo normal heart, redundant multiple supporting systems of myocardial ATP production, transportation, and utilization exist, such that inhibition of one mechanism does not impair the normal left ventricular contractile performance. © 2011 American Heart Association. All rights reserved. Source