Two methods for semi-automated quantification of changes in ventricular volume and their use in schizophrenia

Two semi-automated methods for quantification of ventricular volume change from baseline and follow-up magnetic resonance imaging scans have been deve loped. Technique 1 employs direct segmentation of the ventricles from both the scans using thresholding and contour extraction, Technique 2 operates o n difference images produced by voxel based intensity subtraction of the ba seline from the registered follow-up images. Here, all voxels with intensit ies above a noise threshold and in a restricted area are monitored to compu te volumetric changes. In phantom measurements the first technique was accu rate to 0.0046%, the second to 0.167% of the phantom volume. Results from n ormal volunteers was that the average ventricular volume changed by 1.52% a nd 1.54% for images acquired within 9 months using techniques 1 and 2, resp ectively. With schizophrenic patients mean change of 10.78% and 9.43% were found employing the first and second procedures, respectively. All measurem ents agreed with a radiologist's visual grading of the changes. Robust, obj ective, fast, easy-to-use, and fairly accurate procedures have been develop ed and validated to quantify volumetric changes. (C) 1998 Elsevier Science Inc.