Volumetric MRI evaluation of pituitary on subjects with nondiseased pituitary and MRI follow-up assessment of microprolactinomas treated with cabergoline

Abstrakt

BACKGROUND: Pituitary microadenomas are one the most common pituitary tumors. Among these, prolactionomas are the most common subtype. Most of the patients present with signs and symptoms of prolactin excess. Dopamine agonists are the treatment of choice for most prolactin secreting adenomas with excellent tolerability and long term efficacy.
OBJECTIVES: To assess the temporal relationship of microprolactinoma regression with treatment of cabergoline in treatment naive patients
To generate the normative data of pituitary volume among individuals having no apparent pituitary disease.
PARTICIPANTS: Patients of newly diagnosed pituitary microprolactinomas started on cabergoline therapy & patients undergoing MRI brain for non-pituitary conditions
STUDY DESIGN: Prospective study & cross-sectional study
METHODS: 52 cases of MRI documented microadenomas with raised serum prolactin were studied during the course of the study which lasted for two years. These patients underwent serial MRI Brain with dedicated pituitary protocol at the start of the diagnosis and then at 4/8/12/18/24 months. Volume of adenomas and serum prolactin (PRL) levels were documented and compared with the baseline values. 152 cases of normal pituitary were studied & volume of gland calculated by Di Chiro & Nelson formula.
RESULTS: The mean volume of microadenoma was 247.31 mm3 +-104.41 mm3 with a mean prolactin level of 162.64 ng/ml +- 101.56 ng/ml at the start with a p-value <- 0.0001. Mean adenoma volume at the 24-month period was 50.35 mm3+- 42.44 ng/ml with a mean prolactin level of 30.0 ng/ml +- 25.09 ng/ml with a p-value of <- 0.0001. There was approx. 79% overall reduction of volume of microadenoma on 24 month follow up. The mean PRL levels at the start of the study were 147.27 ng/ml while as mean levels at 24 months was 20.81 ng/ml. More than 75% red of PRL levels was seen in 88.46% of patients with red of less than 75% red of PRL levels in 11.53 % of the patients at 24 months.
Mean pituitary volume was 277.96 mm3 while 267.74 mm3 & 288.74mm3 respectively for males & females.
CONCLUSION: Cabergoline administered for 12-24 months induced a remarkable tumor volume reduction, a disappearance of clinical syptoms of hyperprolactinemia and reduction of serum prolactin levels with an excellent tolerability & patient compliance.
Maximum pituitary volume is noted in pubertal & adolescent while minimum gland volumes are noted at extremes of age.
IMPLICATION: Cabergoline is very effective with excellent long tern tolerance and acceptable side effect
profile in patients of microprolactinomas with symptoms of hyperprolactinemia.
Glands with convex borders are noted in young age groups while minimum volume glands are noted at extremes of ages.
KEYWORDS: MRI- Magnetic resonance imaging, PRL- prolactin.