MR imaging of pituitary adenomas treated with the prolactin inhibitor quinagolide

Purpose: To evaluate the volume of micro- and macroadenomas in quinagolide-treated patients with resistance to or intolerance of bromocriptine.Material and Methods: The effect of the prolactin inhibitor quinagolide on the volume of pituitary adenoma was evaluated retrospectively in 11 female patients. Prolactin levels before and after the treatment were also recorded. The indications for quinagolide therapy were side-effects of bromocriptine in 5 cases, a poor response to bromocriptine in 5 cases and both in 1 case. MR imaging with a 1.0-T magnet was performed to determine the volume reduction of the adenomas.Results: The average volume reduction of macroadenomas was 324 mm³ (46%) and that of microadenomas 73 mm³ (57%). The level of prolactin secreted by macroadenomas was reduced by an average of 163 μg/l (65%) and that by microadenomas of 113 μg (73%). In 2 microadenomas and in 1 macroadenoma, signal intensity changed during the treatment in T1-weighted images. In follow-up no changes in signal intensity were seen in 8 adenomas in non-contrast T1-weighted images. A haemorrhagic lesion was seen in 1 macroadenoma before treatment, but it disappeared during treatment.Conclusion: Quinagolide was found to be an effective alternative to bromocriptine in cases with drug intolerance or resistance, and MR imaging a suitable method for the follow-up of macro- and microadenomas.