[The role of CT and MR in assessing the patient operated on for rectal carcinoma: the local recurrence of the disease].

Computed tomography (CT) and magnetic resonance (MR) findings in a series of 27 patients treated surgically for rectal cancer (13 rectal amputations, 8 sphincter-saving resections and 6 with the Hartmann technique) and affected with local recurrence at the time of examination (1989-1993), were retrospectively reviewed. Every detected lesion was studied relative to morphologic features (shape, outline, surrounding tissue involvement, symmetric growth toward the mid-longitudinal plane), patterns of both CT contrast enhancement and MR signal intensity with different acquisition techniques. The most typical patterns of disease recurrence were: a roundish or nodular shape (the whole group of rectal amputations), irregular outline (25 of 27 cases), infiltrative growth (23 of 27), asymmetry (25 of 27), CT enhancement > 20 HU (24 of 27), medium-high MR signal intensity on T2-weighted images (26 of 27 cases). We report on 5 cases with no positive correlation between CT enhancement and MR signal on T2-weighted images, trying to correlate this disagreement with specific histopathologic patterns.