Abstract #0088

LI J, CAO K, ZHANG X, SUN Y, TANG L

Purpose The Purpose of this study is to evaluate the predictive and early monitoring value of DW-MRI on therapy outcome of combined chemoradiation in patients with primary carcinoma of the rectum. Materials and Methods Fifteen patients with primary rectal carcinoma (cT3) undergoing preoperative chemoradiation were recruited in the study. Diffusion weighted echo planar imaging was performed weekly on all 15 patients during the course of therapy using a GE 1.5T MR scanner with an 8-channel body phase-array coil. The imaging parameters are: TE/TRminimum/6000 msec, FOV36cm, Matrix128x128 Slicethick5mm, Nex8. Two motion-probing gradients (b=0 and b=1000 sec/mm2) were employed to obtain the diffusion Cweighted images. And SENSE (ASSET) technology was also used to reduce the distortion of EPI. The mean ADC values of the tumor region was calculated at before and 1st, 2nd , 4th week of therapy compared with the postsurgical histopathologic results. Results Patients were divided into two groups ac