Dae Jung Kim MD, Presenter: Nothing to Disclose

Joo Hee Kim, Abstract Co-Author: Nothing to Disclose

Joon Seok Lim MD, Abstract Co-Author: Nothing to Disclose

Jae-Joon Chung MD, Abstract Co-Author: Nothing to Disclose

Jeong-Sik Yu MD, Abstract Co-Author: Nothing to Disclose

Myeong-Jin Kim MD, PhD, Abstract Co-Author: Nothing to Disclose

Ki Whang Kim MD, Abstract Co-Author: Nothing to Disclose

In lower rectal cancer, prediction of sphincter involvement and distance from anal verge are important for sphincter saving surgery and treatment planning. Our study was aimed to assess usefulness of pelvic MR with and without gel filling in patients with lower rectal cancer.

Thirty three patients with histologically proved lower rectal cancer (<8cm from the pectinate line, as determined with sigmoidoscopy or rectal exam) were enrolled, during 4 months. High resolution pelvic MR was performed before and after a rectal distention by 500ml of warm ultrasonic gel. Two radiologists, who were blinded to the study, reviewed each set of axial, coronal and sagittal T2-weighted images using five grade scales: sphincter involvement, circumferential resection margin (CRM) involvement and depiction of the tumor. Two radiologists reviewed with consensus each set of MR images for tumor distance from anal verge and T&N staging.

Among them, 25 patients underwent curative resection with (n=11)/ without (n=14) neoadjuvant chemoradiotherapy. Interobserver agreement (kappa=0.58) was moderate. Tumor depiction scores from MR with gel filling were significantly higher than MR without distention (p<0.001) in two reviewers. Comparing to MR without distension, MR with gel filling revealed no significantly different scales of CRM and sphincter involvement (p>0.05). Distance from anal verge was significantly different between MR with gel filling and rigid endoscopy (t-test, p=0.001). There are no statistically differences between pathologic staging and MR staging with/without gel filling (t-test P>0.05).

MR with gel filling is helpful in tumor depiction, but not in prediction of sphincter involvement in lower rectal cancer. Tumor distance from anal verge was exaggerated by gel filling.

MR with gel filling in lower rectal cancer improved tumor depiction, but there were no differences in tumor staging and prediction of CRM/sphincter involvement between MR with and without gel filling.

Kim, D, Kim, J, Lim, J, Chung, J, Yu, J, Kim, M, Kim, K, Preoperative Evaluation of Lower Rectal Cancer by Pelvic MR with and without Gel Filling.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010200.html