intrarater test-retest coefficient of variation of hippocarnpal volumetric measurements is 1.9%

     Validation studies demonstrate that the intrarater test-retest coefficient of variation of hippocarnpal volumetric measurements is 1.9% with this method (Jack, Bentley, Twomey, & Zinsmeister, 1990). The 3D-image data set of each patient is realigned into an orientation perpendicular to the principal axis of the left hippocarnpal formation. The imaging data are then interpolated in-plane to the equivalent of a 512 x 512 matrix and magnified two times. The voxel size of the fully processed image data is 0.316 mm3. The borders of the hippocampi are manually traced on the workstation screen for each image slice sequentially from posterior to anterior.
     Typically, 40 to 50 imaging slices are measured for each hippocampus. In-plane hippocampal anatomic boundaries are defined to include the CA1 to CA4 sectors of the hippocampus proper, the dentate gyrus, and the subiculum (Jack et al., 1997). The posterior boundary of the hippocampus is determined by the oblique coronal anatomic section, in which the crura of the fornices are defined in full profile.

     Pearson correlation coefficients were calculated between the hippocampal volume measured from MRIs obtained at study entry, as well as the participants' baseline Alzheimer's Disease Assessment Scale-Cognitive portion (ADAS-COG) (Rosen, Mohs, & Davis, 1984) and Clinical Dementia Rating (CDR) Sum of Boxes (Morris, 1997), in order to determine the relationship between hippocampal volume and cognitive and functional performance at baseline.