Monitoring early changes in rectal tumor morphology and volume during 5 weeks of preoperative chemoradiotherapy - An evaluation with sequential MRIs.

Purpose: To assess early changes in rectal tumor volume and morphology on sequential MRIs performed during 5 weeks of chemoradiotherapy.

Materials And Methods: Thirteen patients underwent weekly T2W-MRI during 5 weeks of preoperative radiotherapy (total 50 Gy), starting after the first week of radiation. Two radiologists visually evaluated tumor volume and morphology and one reader manually segmented tumors for each time point to quantitatively calculate tumor volumes.