Statistics-based approach for aneurysm volume measurements

Purpose: To evaluate the ability of high-resolution MRA to monitor changes in intracranial aneurysm volume, and devise a highly reliable technique for obtaining these measurements. Materials and Methods: To obtain a baseline estimate of the repeatability of MRA scans and validate the statistics-based technique for aneurysm volume measurement, multiple scans were obtained on individual subjects over a period of up to 1 year. These 3D MRA data sets were coregistered and then analyzed using the volumetric analysis of segmented data and the proposed statistical method. Results: It was shown that high-resolution MRA provides highly repeatable data sets. Both methods used for the aneurysm volume measurements showed consistent results. However, the proposed statistical method had lower error and was much less sensitive to the choice of segmentation parameter than the volumetric analysis of segmented data. A change of 1 mm in the average radius of the aneurysm was detectable with the statistics-based technique. Conclusions: This study demonstrates that the statistical method of aneurysm volume measurement in high-resolution MRA allows reliable and accurate assessments of aneurysm volume changes.