Random-grid stereologic volumetry of MR head scans

Point count stereology is a useful tool in obtaining volumetric measures of objects in three-dimensional (3D) images when the segmentation of objects is not feasible. Presently, fixed-grid 3D stereology is being used where a 3D parallelepiped grid is randomly placed for sampling the image space in order to generate test points. Although this is a popular technique, the use of a fixed grid introduces errors in the final estimate in practice and makes the technique inefficient. Random-grid 3D stereology is introduced to improve the efficiency of the volume estimates in stereology. In this manuscript, we prove random-grid stereology as a more consistent technique than fixed-grid stereology and use it for volumetry of the brain and ventricles in magnetic resonance (MR) head scans. We demonstrate superior efficiency and accuracy of random-grid stereology with experiments. Also, the effects of grid sizes, the optimal directions of sectioning the object for volume estimates of the brain and ventricles, and the reliability of the technique are investigated. J. Magn. Reson. Imaging 2000;12:833-841.