MR-IMAGING IN IDIOPATHIC GROWTH-HORMONE DEFICIENCY

BACKGROUND AND PURPOSE: MR imaging findings of one or more of the foll owing has been suggested to be a sensitive and specific indicator of h ypopituitarism: small anterior pituitary gland, attenuated or absent p ituitary stalk, and ectopic posterior pituitary, We hypothesized that these MR findings would be common in our group of patients with idiopa thic isolated growth hormone deficiency (GHD) or multiple pituitary ho rmone deficiencies (MPHD) and would be a good indicator of the severit y of the hypopituitarism. METHODS: MR images were obtained for 35 pati ents with idiopathic GHD (20 with isolated GHD and 15 with MPHD; age r ange, 2 to 17 years) and analyzed to define one or more of the followi ng triad of abnormalities: 1) small/absent anterior pituitary, 2) trun cated/absent pituitary stalk, and 3) ectopic posterior pituitary, as w ell as for any other associated anomalies. The findings were correlate d with the clinical and biochemical presentation. RESULTS: Pituitary a bnormalities were common in both groups (80% with isolated GHD, 93% wi th MPHD). We found a high frequency of midline CNS malformations, incl uding optic nerve hypoplasia (9%), Chiari type I malformations (20%), and medial deviation of the carotid arteries (37%). Breech delivery, n eonatal hypoglycemia, jaundice, micropenis, or single central incisor occurred equally with both isolated GHD and MPHD, In patients whose pe ak growth hormone level was less than 3 mu g/L (n = 19), 90% had the M R triad, compared with 39% of those with growth hormone levels 3 mu g/ L or greater or less than 8 mu g/L (n = 13) (P < .01). Almost all (92% ) of those with ectopic posterior pituitary had anterior pituitary hei ghts less than -2 SD for age. CONCLUSION: MR abnormalities were common in children with both isolated GHD and MPHD and were closely associat ed with peak growth hormone levels less than 3 mu g/L. The presence of other CNS and clinical findings (eg, single central incisor and micro penis) supports the theory of an embryologic defect as the cause of th e pituitary abnormalities.