ESPE Abstracts

Background: Hypopituitarism in children is a complex condition and its hierarchical evolution at different developmental windows is unpredictable. Magnetic resonance imaging (MRI) is helpful but largely a subjective assessment of anomalies of the hypothalamo-pituitary (H-P) structures. We aimed to test the utility of a quantitative measure of pituitary and stalk in predicting neuroendocrine phenotypes.

Patients and Methods: We recruited 62 patients (28F,34M) with H-P disorders (34 congenital, 28 acquired), followed for 8.0±4.0 years and aged 12.5±2.9 years. We graded neuroendocrine dysfunction by the endocrine morbidity score (EMS) ranging from 0 to 5 (no to 5 pituitary deficits).3T high-resolution volumetric MR brain sequences (T1, T2, CISS) were prospectively acquired to measure Regions of Interest (ROIs):1)Pituitary gland diameters [cranio-caudal (CC) and antero-posterior (AP) on sagittal T1/T2, transverse on coronal T1/T2] and volumes – both indirect (linear measurements) and direct (ROIs),2)Stalk diameters (upper, midpoint, lower on sagittal CISS). Imaging data were compared to those of 25 age- and gender-matched controls (13F,12M, aged 13.6±3.1 years).

Results: 36 had hypopituitarism (EMS≥2, Group1) and 26 had one or no pituitary deficits but may be at risk of evolving endocrinopathies (EMS0-1, Group2). Pituitary diameters [AP (6.3±2.4 vs 8.5±1.6 vs 9.0±1.9 mm, P=0.01) and transverse (10.34±2.8 vs 12.3±2.8 vs 13.6±2.3 mm P=0.01)], indirect volumes (155.6±128.4 mm3 vs 214.2±80.1 vs 395.5±198.1 mm3, <0.0001) and direct volumes (198.7±147.9 vs 349.2±81.4 vs 436.1±225.0 mm3, P<0.001) were lower in Group 1 than in either Group 2 or control. The CC diameter was similar in Group 1 and 2 (4.0±1.6 mm vs 4.0±1.0) but both were lower than in controls (5.8-1.3 mm, P<0.0001). Direct pituitary volumes decreased with increasing EMS (EMS1 351.5±88.7, EMS2 295.6±133.1, EMS3 169.4±200.0, EMS4 130.2±75.7, EMS5 100.3±82.1, P=0.01). Upper, mid, and lower stalk diameters were similar between Group 1 and Group 2 (2.1,1.8,1.7 vs 2.6,2.0,1.7 mm) and did not correlate with increasing EMS. However, the prevalence of observed stalk abnormalities (absent/hypoplastic, interrupted, deviated, thick) increased with higher EMS (EMS0 30.0%, EMS1 46.7%, EMS2 62.5%, EMS3 90.0%, EMS4 87.5%, EMS5 100.0%, P=0.021).

Conclusions: Volumetric assessment of pituitary size may predict the degree of hypopituitarism, whilst linear measurement of pituitary height may be a useful screening tool to identify patients at risk. The degree of stalk slenderness is not additionally predictive, but a qualitative report of any stalk abnormality increases the likelihood of endocrinopathy.