Technical evaluation for MR-venography of lower limb using three-dimensional SMASH

We carried out a technical investigation of lower limb venography by MRI. We initially measured signal intensity under different echo times (TE) and flip angles (FA) using the three-dimensional SMASH method without preparation pulse. Scanning parameters were determined according to agreement of the fat and muscle signals in various TE and FA combinations. We next investigated methods of study. Images were taken in the following order: pre-enhancement, lower-leg arterial phase, lower-leg venous phase, and femoral vein. Contrast medium was infused into a vessel on the back of the hand 30 seconds after obtaining the arterial phase image. Image data were processed by MIP, and we examined the condition of clinical images. The SMASH method with resolved parameters was able to clearly depict vessels including venous aneurysms. It was also useful to determine the orientation of lower-limb veins by obtaining three-dimensional and multidirectional views. Venous images obtained by subtraction technique were useful to diagnose venous thrombosis. We also determined that leg fixation was important in obtaining good venous images by subtraction technique. We also investigated the method of arterial depiction. (author)