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Publications (3)7.19 Total impact

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    ABSTRACT: To determine relative diagnostic value of MR diffusion and perfusion parameters in detection of active small bowel inflammation in patients with Crohn's disease (CD). We reviewed 18 patients with active CD of terminal ileum (TI) who underwent MR enterography (MRE; including dynamic contrast enhanced MRI and diffusion-weighted MRI). Conventional MRI findings of TI were recorded. Regions of interest were drawn over TI and normal ileum to calculate apparent diffusion coefficient (ADC), the volume transfer constant (K(trans)) and the contrast media distribution volume (v(e)). Receiver operating characteristic analysis was used to determine their diagnostic performance. Among conventional MR findings, mural thickening and increased enhancement were present in all actively inflamed small bowel. K(trans), v(e), and ADC values differed significantly between actively inflamed TI and normal ileum (0.92 s(-1) versus 0.36 s(-1); 0.31 versus 0.15 ± 0.08; 0.00198 mm(2)/s versus 0.00311 mm(2)/s; P < 0.001). Area under the curve (AUC) for K(trans), v(e), and ADC values ranged from 0.88 to 0.92 for detection of active inflammation. Combining K(trans) and ADC data provided an AUC value of 0.95. Dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) provide quantitative measures of small bowel inflammation that can differentiate actively inflamed small bowel segments from normal small bowel in CD. DWI provides better sensitivity compared with DCE-MRI and combination of ADC and K(trans) parameters for analysis can potentially improve specificity.
    Journal of Magnetic Resonance Imaging 03/2011; 33(3):615-24. · 2.57 Impact Factor
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    ABSTRACT: The purpose of this study was to test whether an empirical mathematical model (EMM) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can distinguish between benign and malignant breast lesions. A modified clinical protocol was used to improve the sampling of contrast medium uptake and washout. T(1)-weighted DCE magnetic resonance images were acquired at 1.5 T for 22 patients before and after injection of Gd-DTPA. Contrast medium concentration as a function of time was calculated over a small region of interest containing the most rapidly enhancing pixels. Then the curves were fitted with the EMM, which accurately described contrast agent uptake and washout. Results demonstrate that benign lesions had uptake (P<2.0 x 10(-5)) and washout (P<.01) rates of contrast agent significantly slower than those of malignant lesions. In addition, secondary diagnostic parameters, such as time to peak of enhancement, enhancement slope at the peak and curvature at the peak of enhancement, were derived mathematically from the EMM and expressed in terms of primary parameters. These diagnostic parameters also effectively differentiated benign from malignant lesions (P<.03). Conventional analysis of contrast medium dynamics, using a subjective classification of contrast medium kinetics in lesions as "washout," "plateau" or "persistent" (sensitivity=83%, specificity=50% and diagnostic accuracy=72%), was less effective than the EMM (sensitivity=100%, specificity=83% and diagnostic accuracy=94%) for the separation of benign and malignant lesions. In summary, the present research suggests that the EMM is a promising alternative method for evaluating DCE-MRI data with improved diagnostic accuracy.
    Magnetic Resonance Imaging 07/2007; 25(5):593-603. · 2.06 Impact Factor
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    ABSTRACT: To compare conventional fat-suppressed MR images of the breast to images derived from high spectral and spatial resolution MR data. Image quality and the level of fat suppression are compared qualitatively and quantitatively. Women with suspicious breast lesions found on X-ray mammography were imaged on 1.5 Tesla GE SIGNA scanners. High spectral and spatial resolution (HiSS) data were acquired using echo-planar spectroscopic imaging. Images with intensity proportional to the water signal peak height in each voxel were synthesized. Conventional fat-suppressed images were acquired using a frequency selective inversion method. The experimental (HiSS) and conventional images were compared by experienced radiologists to evaluate the quality of fat suppression. In addition, fat suppression and image quality were evaluated quantitatively. Fat suppression, tumor edge delineation, lesion conspicuity, and image texture were improved in the peak height images derived from HiSS data. The results demonstrate that the water peak height images obtained from HiSS data potentially could improve the quality of fat suppression, detection and diagnosis of breast cancer. HiSS allowed detection of lesions and evaluation of lesion morphology prior to contrast media injection. J. Magn. Reson. Imaging 2006. (c) 2006 Wiley-Liss, Inc.
    Journal of Magnetic Resonance Imaging 01/2007; 24(6):1311-5. · 2.57 Impact Factor