[Value of MR tomography vs. CT in the diagnosis of rectal carcinoma and its recurrence].

The value of NMR tomography for the diagnosis of carcinoma of the rectum and of recurrences has been studied, using a 1.5 Tesla NMR apparatus and comparing the results with high resolution CT. There were five patients with a histologically proven primary tumour, eighteen patients with a recurrence and five patients who had had a rectal carcinoma removed, where there was no evidence of recurrence. By obtaining images in three planes, NMR showed the true tumour extent in all cases and was superior to CT in the diagnosis of the primary tumour (in four patients out of five) and in showing recurrences (in five out of eighteen patients). NMR also had advantages in demonstrating lymph node enlargement in the pelvis, where difficulties are often encountered using CT. Early experience with tissue characterisation indicates that it is possible to diagnose rectal tumours confined to that organ. These are usually missed by CT. CT is superior to NMR in demonstrating destructive lesions in bone. Early clinical experience suggests that NMR is a further advance in the early diagnosis of carcinoma of the rectum and of recurrences.