Measurement of global and regional cerebral volume changes by integrating boundary shifts between registered serial 3D MR scans

Abstract

A measure of regional and global cerebral volume change derived directly from registered repeat MR scans is proposed. This measure, the boundary shift integral (BSI), correlated closely with simulated volume change in brain (r=l.000) and ventricles (r=0.999). The BSI was used to determine brain volume loss in 21 control scan pairs and 11 scan pairs from Alzheimer's disease (AD) patients (1 year scan intervals). Loss in the AD group (mean 34.7cc) was widely separated from that in the control group (mean 1.8cc, SD 3.8cc). In contrast, the difference in segmented brain volumes in the AD group (mean 34.9ce) overlapped considerably with that of the control group (mean -2.9cc, SD 13.4cc). The RMS error between repeated measures of the brain BSI was 1.77cc. The ventricular BSI correlated closely with the difference in segmented ventricular volumes (r=0.997), with mean increases of 0.4ce (controls) and 10.1cc (AD). The BSI is both sensitive and highly reproducible.