MR APPEARANCE OF THE INTERNAL ARCHITECTURE OF AMMONS HORN

PURPOSE: To determine whether the four subdivisions of Ammon's horn an d six layers of CA1 seen histologically can be demonstrated with MR im aging. METHODS: Specimens of cadaver brains were imaged in a 3.0-T MR imager with a 3.0-cm solenoid coil. The specimens were sectioned, stai ned, and examined histologically. On anatomic sections, the four subdi visions of Ammon's horn and six layers of CA1 were identified. The MR images were then compared with the anatomic sections. RESULTS: Using g eographic characteristics, we identified the four subdivisions of Ammo n's horn. In CA1, the six layers could be identified by variations in signal intensity, width, and location. CONCLUSION: This study suggests that, with MR imaging of sufficiently high resolution, the internal a rchitecture of Ammon's horn may be identified.