Analysis of indirect signs of microprolactinoma at MR imaging

Abstract

[eng] Objective: To evaluate the diagnostic reliability/value of microprolactinoma indirect signs at MRI. Methods and material: A prospective study was carried out over 3 years on 26 women with microprolactinoma (MiP group) and 106 healthy female volunteers as a control group. Size, glandular morphology, pituitary stalk inclination and sellar bony floor erosion were measured and a comparative statistical analysis between both groups was performed. Results: Patients from the MiP group showed a significantly bigger glandular size than women in the control group, although the glandular morphology did not present significant differences between both groups. Only 5% of normal glands measured over 7.5 mm in height and none of them reached 9 mm, while up to 42.3% of the MiP group scored over 7.5 mm and 19.2% over 9 mm. Mean stalk inclination for the MiP group was 4.6±3.1° and 3.5±2.7° for the control group with no significant differences. Five microprolactinomas were located on the glandular midline, 11 on the left side and ten on the right side. No relationship between the microadenoma location inside the gland and stalk inclination was found. From 21 microprolactinomas with eccentric location, 17 coincided with the sellar floor excavation; eccentric excavation presented significant differences between both groups, but not the central excavation. Conclusion: From all indirect sings of microprolactinoma analyzed in this study, only a gland height over 9 mm, and an eccentric sellar excavation of at least 3 mm are reliable signs to support its diagnosis.