Interuncal distance as a measure of hippocampal atrophy: Normative data on axial MR imaging

PURPOSE: To assess the effects of age and gender on the interuncal distance measured from MR images. METHODS: High-field strength MR Images (axial) of 75 volunteers, 21-82 years old and free of neurologic disorders, were used to measure the interuncal distance. RESULTS: The interuncal distance increased with age (r = 0.66, P <.0001). The mean (SD) interuncal distance for all subjects was 21.4 (4) mm with a range of 12 to 29 mm. CONCLUSIONS: The interuncal distance in healthy subjects is unlikely to exceed 30 mm. Our data may be of clinical significance in view of a previous report stating that the interuncal distance may be enlarged in pathologic hippocampal degeneration, such as in patients with Alzheimer disease.