title: JOURNAL CLUB: Preoperative MRI Evaluation of Primary Rectal Cancer: Intrasubject Comparison With and Without Rectal Distention.
abstract: OBJECTIVE
  The aim of this study was to determine whether rectal distention influences the accuracy of MRI for tumor staging and for measuring of maximal extramural depth of tumor spread and distance between tumor and mesorectal fascia (MRF).
  
  
  METHODS
  Fifty patients with rectal carcinoma underwent MRI before and after rectal distention. Both sets of MR images were reviewed by two radiologists. The scores for depiction of the mass (1-4 scale), T and N category, distance from normal rectal wall to MRF, maximal extramural depth of tumor spread, and distance between tumor and MRF were evaluated.
  
  
  RESULTS
  The visualization scores on MR images obtained with the rectum distended were significantly higher than those on images obtained without distention (90% vs 58% for score 4, p < 0.001). The accuracy of T category assessed on distended images was slightly higher than the accuracy on nondistended images (88.6% vs 84.1% for observer 1, 84.1% vs 81.8% for observer 2), but the accuracy of N category was stable. The distance between normal rectal wall and MRF was significantly less on distended images than on nondistended images (p < 0.05). However, there was no significant difference between nondistended and distended images for maximal extramural depth and distance between tumor and MRF (p > 0.05).
  
  
  CONCLUSIONS
  Rectal distention significantly improved visualization of tumors on MR images. It also improved T category assessment to some extent. Although the distance between normal rectal wall and MRF was significantly less with rectal distention than without rectal distention, maximal extramural depth and the distance between tumor and MRF did not vary significantly with or without rectal distention.
authors.affiliation: 1 Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Ye
authors.affiliation: 1 Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: 1 Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Liang
authors.affiliation: 1 Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Han
authors.initials: H
authors.lastname: Ouyang
authors.affiliation: 1 Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Xinming
authors.initials: X
authors.lastname: Zhao
authors.affiliation: 1 Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Chunwu
authors.initials: C
authors.lastname: Zhou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011300:Preoperative Care; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery
keywords: distention; extramural spread; mesorectal fascia; pelvic MRI; rectal cancer