COMPARISON OF COMPUTERIZED-TOMOGRAPHY AND MAGNETIC-RESONANCE-IMAGING FOR THE EXAMINATION OF THE PITUITARY-GLAND IN PATIENTS WITH CUSHINGS-DISEASE

OBJECTIVE The vast majority of patients with Cushing's disease have a corticotroph adenoma, the selective removal of which, through the tran ssphenoidal route, has the potential to offer a definitive and complet e cure. This study was designed to compare the diagnostic accuracy of computerized tomography (CT) and magnetic resonance imaging (MRI) to i dentify the presence, evaluate the size, and assess the topographic ch aracteristics of pituitary corticotroph adenomas. METHODS Forty-two pa tients with Cushing's disease were included in this prospective study, of whom 16 were subsequently explored transsphenoidally. Computerized tomography used a CE 12000 CGR apparatus with 1.5-mm coronal slices a nd a 2-mm interslice gap. Magnetic resonance imaging used an MR Max 0. 5T GE apparatus; adjacent 3-mm slices were obtained with a T1-weighted gradient echo before and after gadolinium injection. RESULTS Lesions compatible with an adenoma were identified in 29 patients by MRI and i n 21 patients by CT (69 vs 50%, P < 0.02). Seven macroadenomas were id entified as well by the two methods. Eight of the 22 microadenomas det ected by MRI were not identified by CT. Evidence for intracavernous tu mour extension was found in nine patients: it was more frequently dete cted by MRI (8 patients) than by CT (4 patients). Fourteen patients wi th positive MRI had a pituitary examination: in one case the adenoma c ould not be reached because of purely suprasellar location; of the oth er 13 all were found by the surgeon and the surgical outcome was succe ssful in 12 cases. CONCLUSION MRI is superior to CT for the examinatio n of the pituitary gland in patients with Cushing's disease.