Aziz H. Poonawalla

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PURPOSE To develop an analytical formalism describing how noise and selection of diffusion-weighting scheme propagate through the diffusion tensor imaging (DTI) computational chain into variances of the diffusion tensor elements, and errors in the relative anisotropy (RA) and fractional anisotropy (FA) indices. MATERIALS AND METHODS Singular-value(More)
BACKGROUND Gray matter lesions are known to be common in multiple sclerosis (MS) and are suspected to play an important role in disease progression and clinical disability. A combination of magnetic resonance imaging (MRI) techniques, double-inversion recovery (DIR), and phase-sensitive inversion recovery (PSIR), has been used for detection and(More)
PURPOSE To prospectively perform a direct measurement of fractional anisotropy (FA) and mean diffusivity (MD) in cortical lesions of patients with multiple sclerosis (MS). MATERIALS AND METHODS The study was approved by the institutional review board and was HIPAA compliant; informed consent was obtained. Magnetic resonance (MR) images, including double(More)
BACKGROUND AND OBJECTIVES Based on the application of newer magnetic resonance imaging (MRI) acquisition sequences, the detection of cortical lesions (CL) in multiple sclerosis (MS) has significantly improved. Double inversion recovery (DIR) at 3T has increased the detection sensitivity and classification specificity when combined with phase sensitive(More)
An algorithm for correcting the geometric distortions in the echo planar images and diffusion weighted images is described. In this method the geometric distortion in the echo planar imaging (EPI) data is corrected by non-rigid registration to conventional fast-spin echo (FSE) images. The registration is based on a variant of the Demon's algorithm [10] with(More)
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