Amol Pednekar

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Accurate delineation of the left ventricular myocardial boundaries on cardiac cine magnetic resonance (MR) images is essential for volumetric and functional cardiac analysis. Automated myocardial contour delineation often suffers from misalignment of slices, nonuniform coil sensitivity, blood-flow-related inter- and intraslice intensity inhomogeneities,(More)
Traditional segmentation techniques do not quite meet the challenges posed by inherently fuzzy medical images. Image segmentation based on fuzzy connectedness addresses this problem by attempting to capture both closeness, based on characteristic intensity, and "hanging togetherness," based on intensity homogeneity, of image elements to the target object.(More)
BACKGROUND Radiofrequency (RF) shading artifacts degrade image quality while performing cardiovascular magnetic resonance (CMR) at higher field strengths. In this article, we sought to evaluate the effect of local RF (B1 field) shimming by using a dual-source-transmit RF system for cardiac cine imaging and to systematically evaluate the effect of subject(More)
PURPOSE To evaluate the technical feasibility of two approaches--dual-contrast (DC) cluster analysis, and scout geometry (SG)--for automatic identification of the left ventricular (LV) cavity in short-axis (SA) cine-MR images. MATERIALS AND METHODS The DC algorithm uses Fuzzy C-Means (FCM) cluster analysis of SA images from a black-blood double-inversion(More)
To confirm the feasibility of breath-hold DCE-MRI and DWI at 3T to obtain the intra-abdominal quantitative physiologic parameters, K trans, k ep, and ADC, in patients with untreated pancreatic ductal adenocarcinomas. Diffusion-weighted single-shot echo-planar imaging (DW-SS-EPI) and dynamic contrast-enhanced (DCE) MRI were used for 16 patients with newly(More)
BACKGROUND Cine balanced steady-state free precession (SSFP), the preferred sequence for ventricular function, demands uninterrupted radio frequency (RF) excitation to maintain the steady-state during suspended respiration. This is difficult to accomplish in sedated children. In this work, we validate a respiratory triggered (RT) SSFP sequence that drives(More)
We present an automated left ventricular (LV) myocardial boundary extraction method. Automatic localization of the LV is achieved using a motion map and an expectation maximization algorithm. The myocardial region is then segmented using an intensity-based fuzzy affinity map and the myocardial contours are extracted by cost minimization through a dynamic(More)
Abdominal visceral fat accumulation is one of the most important cardiovascular risk factors. Currently, computed tomography and magnetic resonance images are manually segmented to quantify abdominal fat distribution. The manual delineation of subcutaneous and visceral fat is labor intensive, time consuming, and subject to inter- and intra- observer(More)
In this paper, we present an enhancement of the fuzzy connectedness-based image segmentation method based on dynamic computation of adaptive weights for the homogeneity and the directional gradient energy functions. Adaptive weights enhance the performance and robustness of the conventional fuzzy connectedness-based segmentation while decreasing the degree(More)
PURPOSE To obtain high temporal resolution (HTR) magnetic resonance (MR) steady-state free-precession (SSFP) cine cardiac images by using multichannel radiofrequency (RF) hardware and parallel imaging techniques; to study the effect of temporal resolution; and to compare the derived left ventricular (LV) diastolic filling parameters with echocardiographic(More)