MR EVALUATION OF PATIENTS WITH CONGENITAL HYPOSMIA OR ANOSMIA

OBJECTIVE. The purpose of this study was to evaluate patients with red uced or no sense of smell since birth for sites of abnormality by MR i maging. MATERIALS AND METHODS. Twenty-five patients who reported no ol factory function since birth were evaluated by olfactory testing, sino nasal endoscopy, and MR imaging. Surface coil and head coil images of the olfactory bulbs, olfactory tracts, subfrontal cortex, and temporal lobes in contiguous 3-mm sections were obtained. Two reviewers determ ined unilateral olfactory bulb and tract volumes and temporal lobe vol umes in two separate sessions. Qualitative grading for olfactory bulb, olfactory tract, olfactory sulcus, subfrontal region, hippocampus, an d temporal lobe damage also was performed. RESULTS. The absence of olf actory bulbs and tracts (68-84%) or the presence of hypoplasia (16-32% ) was noted in all cases. Eight individuals had Kallmann's syndrome (h ypogonadotropic hypogonadism with anosmia). Temporal and/or frontal lo be volume loss was noted in five individuals and was mild in all but o ne individual. CONCLUSION, Congenital anosmia or hyposmia appears to b e an olfactory bulb-olfactory tract phenomenon rather than a cerebral process.