MR Evaluation in Patients with Isolated Anosmia Since Birth or Early Childhood

BACKGROUND AND PURPOSE: Anosmias with chromosomal disorders has been well in-vestigated. However, isolated anosmia (IA) has received less attention, although it occurs more frequently. We compared frontobasal structures in patients with IA since birth or early childhood with those in control subjects. METHODS: Imaging findings obtained in 16 patients with IA were compared with those obtained in eight control subjects. Imaging was performed with a standard quadrature head coil at 1.5 T. T1-weighted spin-echo (coronal plane perpendicular to frontal skull base; section thickness, 3 mm; pixels, 0.43 0.39 mm) and sagittal T1-weighted magnetization-prepared rapid gradient-echo (voxels, 1.0 1.0 1.0 mm) sequences were performed. We assessed the length and depth of the olfactory sulcus, olfactory bulb volume, and olfactory sulcus depth in the plane of the posterior tangent through the eyeballs (PPTE). RESULTS: Five patients with IA had bilateral hypoplastic olfactory bulbs. Three patients with IA had hypoplastic olfactory bulbs on the right and aplastic olfactory bulbs on the left. Eight patients with IA had bilaterally aplastic olfactory bulbs. The depth of the olfactory sulcus at the level of the PPTE was smaller in patients with IA than in control subjects. The depth o