Yousef Mazaheri

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A multishot partial-k-space EPI technique is presented and validated by fMRI at high spatial resolution. High-resolution phase maps corrected by phase-encoded reference scans have less off-resonance effects. Phantom studies demonstrate that this method can substantially improve partial-k-space EPI image formation. BOLD fMRI at submillimeter spatial(More)
The 3D TRICKS method for contrast-enhanced, time-resolved MR DSA has been recently described. In this paper, computer simulations are used to investigate the relative frame rate, temporal window, artery-vein temporal separation, contrast-to-noise ratio, and spatial resolution of TRICKS and conventional scans for breath-hold and non-breath-hold applications.(More)
PURPOSE To extend the intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) model to restricted diffusion and to simultaneously quantify the perfusion and restricted diffusion parameters in neck nodal metastases. MATERIALS AND METHODS The non-gaussian (NG)-IVIM model was developed and tested on diffusion-weighted MRI data collected on a(More)
PURPOSE To compare ADC values measured from diffusion-weighted MR (DW-MR) images of the prostate obtained with both endorectal and phased-array coils (ERC+PAC) to those from DW-MRI images obtained with an eight-channel torso phased-array coil (PAC) at 3.0 T. METHODS The institutional review board issued a waiver of informed consent for this(More)
Information theory provides a mathematical framework for analysis of fMRI experiments. By modeling the fMRI experiment as a communication system, various results from information theory can be applied to measure information transfer rate in fMRI experiments. The information transfer rate has important implications for design and analysis of brain-computer(More)
The signal intensity during the dynamic approach to the equilibrium state of longitudinal magnetization is a function of sequence parameters, such as repetition time and flip angle, and depends on tissue characteristics, including longitudinal relaxation time of stationary tissue and the rate of blood inflow. A method is presented to extract information(More)
PURPOSE This study aimed to compare the intraclass correlation coefficients of parameters estimated with stretched exponential and biexponential diffusion models of in vivo diffusion-weighted magnetic resonance imaging (MRI) of the prostate. METHODS After the institutional review board issued a waiver of informed consent for this Health Insurance(More)
PURPOSE To investigate whether tumor volume derived from apparent diffusion coefficient (ADC) maps (VolumeADC) and tumor mean ADC value (ADCmean) are independent predictors of prostate tumor Gleason score (GS). EXPERIMENTAL DESIGN Tumor volume and GS were recorded from whole-mount histopathology for 131 men (median age, 60 years) who underwent endorectal(More)
The sensitivities of phase-difference (PD) and complex-difference (CD) processing strategies to in-plane motion were examined theoretically and experimentally. Errors in velocity and volume flow rate (VFR) estimates were attributed to (a) motion between different velocity encodings and, in the case of segmented k-space acquisition strategies, (b) motion(More)