High-resolution T2-weighted (T2W) oblique plane turbo spin-echo (TSE) MRI for rectal adenocarcinoma staging

PURPOSE: The purpose of this study was to determine the frequency/significance of incorrectly planned oblique T2-weighted (T2W) MRI of rectal adenocarcinoma. METHODS: Eighty-six consecutive patients underwent MRI for rectal cancer staging. Two radiologists evaluated oblique T2W imaging and tumor stage. RESULTS: A total of 71% of middle/high tumors had correctly planned oblique T2W-MRI. Thirteen of 14 low tumors (N=7) or tumors spanning at least two rectal segments (N=7) had incorrectly planned oblique T2W-MRI. The sensitivity/specificity of staging on correct compared to incorrect oblique T2W was: 88.9/50% (R1)/77.8/60% (R2) and 80/100% (R1)/60/80% (R2), (P=.54). Agreement was substantial, K=0.67. CONCLUSIONS: Oblique T2W-MRI is incorrectly performed in low tumors and those spanning multiple rectal segments. In this study, planning errors did not impact staging accuracy.