Image Contrast and Hippocampal Volumetric Measurements

The objective was to assess the influence of image contrast on the repeatability of hippocampal measurements. We compared measurements on spoiled GRASS (SPGR) three-dimensional acquisition with measurements on inversion pulse prepared spoiled GRASS (IRSPGR) three-dimensional acquisition. IRSPGR images had a higher grey matter-white matter contrast than SPGR images. Repeated measurements of hippocampi of 13 subjects were performed on both SPGR and IRSPGR images and the standard deviation of the differences of repeated measurements calculated. SD was 239 mm3 for SPGR and 134 mm3 for IRSPGR. Our data suggest that higher image contrast improves the repeatability of hippocampal measurements.