title: Evaluation of gadolinium-enhanced T1-weighted magnetic resonance imaging in the preoperative assessment of local staging in rectal cancer.
abstract: OBJECTIVE
  The aim of this study was to determine whether gadolinium-enhanced T1-weighted magnetic resonance (MR) sequence is beneficial in the preoperative assessment of tumour and nodal staging in patients with primary rectal cancer.
  
  
  METHODS
  Eighty-eight patients with primary rectal cancer underwent preoperative MR imaging, followed by surgical resection. Two radiologists independently reviewed (i) T2-weighted MR images (T2WI); (ii) gadolinium-enhanced T1-weighted MR images (T1 + Gd); (iii) MR combined with T2WI and T1 + Gd for the prediction of tumour and nodal stage compared with histopathologic findings as the end point. Differences in the diagnostic performance of T2WI only, T1 + Gd image only and combined T2WI and T1 + Gd MR images were analyzed by comparing areas under receiver operating characteristic curves (Az) for each reader. Interobserver agreement was also calculated.
  
  
  RESULTS
  There was no significant difference in the Az values of T2WI only, T1 + Gd image only and combined T2WI and T1 + Gd images for the prediction of tumour staging (Az of T2WI, T1 + Gd and combined MR images for reader 1, 0.80, 0.76 and 0.85; reader 2, 0.83, 0.82 and 0.87) and nodal staging (Az for reader 1, 0.73, 0.73 and 0.81; reader 2, 0.79, 0.80 and 0.83). Interobserver agreement for the prediction of tumour staging was moderate to substantial, while only fair agreement was noted for the prediction of nodal staging.
  
  
  CONCLUSIONS
  Gadolinium-enhanced T1-weighted MRI did not increase the diagnostic yield for tumour and nodal staging, and may be omitted in the MR protocol for preoperative assessment of primary rectal cancer.
authors: Department of Diagnostic Radiology, Chang Gung Memorial Hospital, College of Medicine and School of Medical Technology, Chang Gung University, Putz City, Chia-Yi County, Taiwan.
authors: S-Y
authors: SY
authors: Jao
authors: B-Y
authors: BY
authors: Yang
authors: H-H
authors: HH
authors: Weng
authors: C-H
authors: CH
authors: Yeh
authors: L-W
authors: LW
authors: Lee
mesh_terms: D000368:Aged; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011237:Predictive Value of Tests; D011300:Preoperative Care; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D005682:Gadolinium