MR Imaging Detection of Pituitary and Brain Anomalies in Pituitary Dwarfs

Idiophatic deficiency of growth hormone (IGHD) is the most common cause of pituitary dwarfism. Relationship with birth trauma (Shizume et al. 1977) and radiological pituitary abnormalities were reported, even though a clear syndrome was never demonstrated. In 1964 Fisher and Di Chiro reported a high percentage of small sellae in IGHD patients with onset of hypopituitary symptoms before the age of 6 years. This observation was later supported by CT scan (Stanhope et al. 1986;Inoue et al. 1986) that confirmed the high frequency of both sella and pituitary hypopla sia, also associated with the failure in the detection of the pituitary stalk. 1.5 T MR imaging with thin slice (3 mm) T1-weighted images (T1-WI) technique, is the most accurate diagnostic tool in the depiction of the sellar and parasellar anatomy (Fujisawa et al. 1987a). Moreover it is now confidently proven that MR i-maging can differentiate anterior pituitary (adenohypophysis) from posterior pituitary (neurohypophysis) (Colombo et al. 1987). For these reasons it was recently used for a better evaluation of the pituitary anomalies in IGHD patients. The preliminary MR imaging reports (Fujisawa et al. 1987b; Triulzi et al. 1987; di Natale et al. 1987; Kelly et al. 1988) showed a recurrent hypothalamic-hypophyseal abnormality (Fig. 1) that can be summarized as follows: a) severe hypoplasia of both sella and pituitary gland with absence of posterior pituitary hyperintensity; b) absence of the pituitary stalk with evidence of a residual infundibular nodule; c) T1-WI hyperintensity at the level of the residual stalk (posterior pituitary ec topia). In order to evaluate on a large population these preliminary MR findings and to correlate them with the endocrinological data we studied 59 patients with IGHD by MR imaging at 1.5 T.