Magnetic resonance imaging of the brain in idiopathic hypogonadotropic hypogonadism.

Magnetic resonance imaging (MRI) of the pituitary, hypothalamus and olfactory sulci was performed in 40 patients with idiopathic hypogonadotropic hypogonadism (IHH). Twelve of these patients had an impaired sense of smell (Kallmann's syndrome). Sagittal and coronal imaging revealed no morphological abnormalities in the hypothalamic-pituitary region. On axial imaging rudimentary, hypoplastic or aplastic olfactory sulci were found in eight cases. All patients with olfactory sulcal abnormalities had associated hyposmia (one case) or anosmia (seven cases). Structural defects identifiable on MRI were present only in 20 per cent of patients with IHH.