Predictive value of preoperative magnetic resonance imaging of the pituitary for surgical cure in Cushing's disease.

AIM Cushing's disease (CD) is caused by ACTH-secreting pituitary adenoma. Transsphenoidal surgery (TSS) is the treatment of choice. CD diagnosis must be based on biochemical confirmation of hypercortisolemia and visualization of pituitary tumor on magnetic resonance imaging (MRI). Diagnostic problems are associated with equivocal or even normal MRI. In such situations, some neurosurgical centers perform a diagnostic sellar exploration. The purpose of this study was to evaluate the relationship between the results of preoperative MRI of the pituitary and efficacy of TSS for CD. MATERIAL AND METHODS A prospective study enrolling 36 consecutive patients with biochemically confirmed CD operated on and then followed up for at least 18 months. RESULTS 23 of 36 patients (63,9%) were cured. Persistent CD was confirmed in 13 patients (36,1%). A difference was demonstrated between both groups with reference to the preoperative MR findings. In the cured group there was a significantly greater number of patients with precisely visualized pituitary microadenoma whereas in the non-cured group there was a significantly greater number of patients with pituitary macroadenoma or equivocal result of MRI (p=0.036). CONCLUSION Precise localization of corticotroph microadenoma on the preoperative MRI may be considered as one of predictive factors positively prognosticating cure after TSS for CD.