Contrast optimization for assessment of the colonic wall and lumen in MR colonography.

This report focuses on the optimization of magnetic resonance colonography for combined virtual endoluminal and T2-weighted wall analysis of the colon and demonstrates the potential of the single-shot fast spin-echo (SSFSE) sequence for identifying colorectal pathologies. A 45 degrees flip angle in the three-dimensional spoiled gradient-echo sequence and a TE of 60 msec in the SSFSE sequence in conjunction with a 10 mM gadolinium concentration in the enema results in maximal contrast for the delineation of the colonic lumen in T1-weighted imaging and the colonic wall in T2-weighted imaging. The SSFSE sequence reveals hyperintense signal for inflammatory disease and most polyps exceeding 10 mm in size. It supplements the virtual endoluminal assessment by aiding in the differentiation between mass lesions and fecal matter or residual air.