Abstract: . . .  Analysis of Subtraction Methods in 3D MR DSA for Peripheral Vascular Disease Yuexi Huang, CA Webster, GA Wright Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada Introduction 3D contrast enhanced MR angiography is . . .
. . .  magnitude is Rayleigh distributed. After doing the MIP projection, the mean of the distribution gets bigger, while the deviation gets smaller 4 . Figure 3. Simulation of noise distribution after subtraction- MIPs. The original complex data of a 256 ` 256 ` 60 matrix is Gaussian distributed with zero mean and standard deviation 1.  . . .
. . .  The purpose of subtraction is to improve arterial conspicuity by suppressing veins and background tissues. In arterial regions where there is significant signal both in the mask and new data sets, signal variability is similar in all post-processing methods described here 3 . Specifically, all yield similar vessel intensities, demonstrating the lack of partial volume effects at high resolution. Generally, arterial SNR is degraded by subtraction since signal is removed while noise variance . . .
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