The accuracy of Multi-detector row CT for the assessment of tumor invasion of the mesorectal fascia in primary rectal cancer.
OBJECTIVE
To evaluate the accuracy of Multi-detector row CT (MDCT) for the prediction of tumor invasion of the mesorectal fascia (MRF).


METHODS
A total of 35 patients with primary rectal cancer underwent preoperative staging magnetic resonance imaging (MRI) and MDCT. The tumor relationship to the MRF, expressed in 3 categories (1--tumor free MRF = tumor distance > or = 1 mm; 2--threatened = distance < 1 mm; 3--invasion = distance 0 mm) was determined on CT by two observers at patient level and at different anatomical locations. A third expert reader evaluated the MRF tumor relationship on MRI, which served as reference standard. Receiver operating characteristic curves (ROC-curves) and areas under these curves (AUC) were calculated. The inter-observer agreement of CT was determined by using linear weighted kappa statistics.


RESULTS
The AUC of CT for MRF invasion was 0.71 for observer 1 and 0.62 for observer 2. The inter-observer agreement was kappa = 0.34. The performance of CT at mid-high rectal levels was statistically significant better compared to low anterior (obs.1: AUC = 0.88 vs. 0.50; obs 2: AUC = 0.84 vs. 0.31; P < or = 0.040).


CONCLUSIONS
Multi-detector row CT has a poor accuracy for predicting MRF invasion in low-anterior located tumors. The accuracy of CT significantly improves for tumors in the mid-high rectum. There is a high inconsistency among readers.
Vliegen
Roy
R
Department of Radiology, University Hospital of Maastricht, Maastricht, The Netherlands. royvliegen@hetnet.nl
Dresen
Raphaela
R
Beets
Geerard
G
Daniels-Gooszen
Alette
A
Kessels
Alfons
A
van Engelshoven
Jos
J
Beets-Tan
Regina
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D003287:Contrast Media; D005205:Fascia / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000473:pathology*; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media