MR VOLUMETRY FOR MONITORING INTRAMUSCULAR BROMOCRIPTINE TREATMENT IN MACROPROLACTINOMAS

Objective: To assess volumetric changes of pituitary prolactinomas, we applied a threshold-based segmentation algorithm in two patients duri ng intramuscular bromocriptine treatment. Materials and Methods: Tumor volumes were calculated from contiguous slices of a 3D GE sequence an d from conventional SE images. Results: After a single 50 mg i.m. brom ocriptine administration, the prolactinoma volumes decreased by 25 and 35% within 7 and 11 days, respectively. Volume calculations from 3D G E images were more accurate than calculations from 3 mm 2D SE images, especially for smaller tumors. A decrease of prolactinoma size was par alleled by a decrease of serum prolactin levels and correlated with an improvement of visual field and endocrine function in both patients. The end of the bromocriptine effect was indicated by a reincreasing tu mor volume, which was observed after 30 days in the first patient and after 43 days in the second patient. Conclusion: Our results suggest t hat MR volumetry represents a useful tool to monitor changes of prolac tinoma volume during bromocriptine treatment and may improve the clini cal management of these patients.