QUANTITATION OF NORMAL CANINE HIPPOCAMPUS FORMATION VOLUME - CORRELATION OF MRI WITH GROSS HISTOLOGY

The hippocampal formation possesses an important role in the developme nt and maintenance of shortterm memory, In this study, magnetic resona nce imaging (MRI) and gross histology were used to quantify the volume of the hippocampal formation in canines. High resolution MRI, using 1 mm thick slices and an intraplanar resolution of 0.35 mm was performe d at 2.0 T both in vivo and in vitro following in situ fixation. The v olumes of the hippocampal formations were determined from MR images an d compared to those obtained from one mm thick gross histologic sectio ns. The average volume of the canine hippocampal formation, measured f rom in vivo and in vitro MR images was 476.0+/-79.5 and 467.3+/-53.7 m m(3), respectively, Determined from gross histology, the volume of the hippocampal formation was 463.6+/-24.1 mm(3). Quantitation of the can ine hippocampal formation using in vivo MRI showed good correlation wi th in vitro MRT and histology, verifying the reliability and reproduci bility of in vivo MRT measurements. High resolution MRI using 1 mm thi ck slices through the whole canine hippocampal formation is necessary for accurate volume determination of a structure of this size.