MRI VERSUS CT IN THE DIAGNOSIS OF NELSONS SYNDROME

The purpose of the study was to evaluate the utility of MRI and CT in the diagnosis of Nelson's syndrome, i.e. pituitary tumours in patients bilaterally adrenalectomized for Gushing's disease. Thirteen patients , followed up for 5-29 years after adrenalectomy were studied. In 6 of them CT and MRI revealed no changes in the pituitary gland. In the re maining 7 patients only three CT scans were suggestive of a pituitary adenoma. MRI studies with administration of gadodiamide confirmed the CT diagnosis of Nelson's tumour in 3 patients and disclosed microadeno mas in a further 4 patients. Neurosurgical treatment in 4 patients con firmed the MRT findings. Additionally CT and MRI examinations were per formed in 5 patients suspected of a recurrent Nelson's tumour 3-11 yea rs after neurosurgery. MRI visualized recurrent adenomas in 3 patients that were not well seen by CT scans. In our experience MRI was more e ffective than CT in the diagnosis of Nelson's syndrome.