title: Does gadolinium-based contrast material improve diagnostic accuracy of local invasion in rectal cancer MRI? A multireader study.
abstract: OBJECTIVE. The purpose of this study was to compare reader accuracy and agreement on rectal MRI with and without gadolinium administration in the detection of T4 rectal cancer. MATERIALS AND METHODS. In this study, two radiologists and one fellow independently interpreted all posttreatment MRI studies for patients with locally advanced or recurrent rectal cancer using unenhanced images alone or combined with contrast-enhanced images, with a minimum interval of 4 weeks. Readers evaluated involvement of surrounding structures on a 5-point scale and were blinded to pathology and disease stage. Sensitivity, specificity, negative predictive value, positive predictive value, and AUC were calculated and kappa statistics were used to describe interreader agreement. RESULTS. Seventy-two patients (38 men and 34 women) with a mean age of 61 years (range, 32-86 years) were evaluated. Fifteen patients had 32 organs invaded. Global AUCs without and with gadolinium administration were 0.79 and 0.77, 0.91 and 0.86, and 0.83 and 0.78 for readers 1, 2, and 3, respectively. AUCs before and after gadolinium administration were similar. Kappa values before and after gadolinium administration for pairs of readers ranged from 0.5 to 0.7. CONCLUSION. On the basis of pathology as a reference standard, the use of gadolinium during rectal MRI did not significantly improve radiologists' agreement or ability to detect T4 disease.
authors.affiliation: 1 Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY 10065.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Gollub
authors.forename: Yulia
authors.initials: Y
authors.lastname: Lakhman
authors.forename: Katrina
authors.initials: K
authors.lastname: McGinty
authors.forename: Martin R
authors.initials: MR
authors.lastname: Weiser
authors.forename: Michael
authors.initials: M
authors.lastname: Sohn
authors.forename: Junting
authors.initials: J
authors.lastname: Zheng
authors.forename: Jinru
authors.initials: J
authors.lastname: Shia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D015588:Observer Variation; D012004:Rectal Neoplasms / Q000473:pathology*; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D005682:Gadolinium
keywords: MRI; diagnostic accuracy; gadolinium; reader performance; rectal cancer