Magnetic resonance imaging in growth hormone deficiency: relationship between endocrine function and morphological findings.

Magnetic resonance imaging (MRI) using gadopentetate dimeglumine (Gd-DTPA) improves the delineation of hypothalamic-pituitary structures and facilitates the detection of anatomical abnormalities which are indicators of permanent growth hormone deficiency (GHD). The aim of this study was to determine the frequency of neuroradiological abnormalities in 85 (52 M, 33 F) patients with hereditary or idiopathic forms of isolated GHD (IGHD) or multiple pituitary hormone deficiency (MPHD) and also to investigate the relationship between anatomical findings and hormonal status. Pituitary hypoplasia with absent or thin infundibulum and ectopic posterior pituitary (EPP) were the most frequent findings in 39 patients with MPHD, whereas in 46 patients with IGHD the most frequent finding was pituitary hypoplasia without neuroradiological abnormalities. All patients whose infundibulum was not visualized after Gd-DTPA injection belonged to the MPHD group; therefore, absence of pituitary stalk can be a good indicator of the severity of hormonal deficiencies. Pituitary hypoplasia was found in all patients with familial IGHD. Among patients with abnormalities of the hypothalamic pituitary area on MRI, normal or breech delivery frequency distributed equally. Therefore it seems that mechanical or hypoxic prenatal events cannot be the primary etiological factor in all patients with neuroradiological abnormalities since half of these patients had normal delivery and birth history. The localization of the bright spot of the posterior pituitary at the level of the median eminence, midstalk position or at the end of the infundibulum may suggest a neuronal migration defect which may occur during early embryogenesis. In conclusion, in children with GHD a careful examination of the hypothalamic pituitary area by MRI after enhancement helps to establish the diagnosis and predicts the prognosis.