Automatic scan prescription for brain MRI.

Diagnostic brain MRI scans are usually performed by trained medical technologists who manually prescribe the position and orientation of a scanning volume. In this study, a fully automatic computer algorithm is described which compensates for variable patient positioning and acquires brain MRI scans in a predefined reference orientation. The method involves acquiring a rapid water-only pilot scan, segmenting the brain surface, and matching it to a reference surface. The inverse matching transformation is then used to adapt a geometric description of the desired scanning volume, defined relative to the reference surface, to the current patient. Both pilot scan and processing are performed within 30 sec. The method was tested in 25 subjects, and consistently recovered orientation differences between the reference and each subject to within +/-5 degrees. Compared to manual prescription, automatic scan prescription promises many potential benefits, including reduced scan times, reproducible scan orientations along anatomically preferable orientations, and better reproducibility for longitudinal studies. Magn Reson Med 45:486-494, 2001.