KALLMAN SYNDROME VERSUS IDIOPATHIC HYPOGONADOTROPIC HYPOGONADISM AT MR-IMAGING

PURPOSE: To identify morphologic differences between Kallman syndrome (KS) and idiopathic hypogonadotropic hypogonadism (IHH) and establish a role for magnetic resonance (MR) imaging in these disorders. MATERIA LS AND METHODS: Twenty-eight patients were compared with 10 eugonal ma le volunteers. Eighteen patients had KS (hypogonadotropic hypogonadism with anosmia) and 10 had IHH. All participants underwent hormone anal ysis, a sniff-bottle smell test, and gadolinium-enhanced MR imaging. C hanges in the hypothalamic-hypophyseal region and the rhinencephalon w ere evaluated. RESULTS: MR imaging revealed intracranial morphologic c hanges in all patients on plain T1-weighted sections. Seventeen patien ts with KS demonstrated aplasia of an olfactory bulb; one olfactory su lcus was absent in six, rudimentary in four, and normal in eight. Olfa ctory bulbs were present in all 10 IHH patients and three showed one s lightly hypoplastic bulb. Ten patients with KS and three with IHH show ed an enlarged paranasal sinus system. Further MR findings were simila r. CONCLUSION: MR imaging demonstrates abnormalities of the rhinenceph alon present in KS patients and occasionally absent in IHH patients.