An image processing and 3-D display method was developed for MRI of pituitary gland hematomas. MRI was performed with a TOSHIBA MRT-15A resistive magnetic system. The visualized anatomical region was recorded on film in constant slice intervals. Image data were taken with a TV camera and digitized into 256 gray levels on a 512×512 array of points. The boundaries of the pituitary gland, ventricles and brain were extracted by region segmentation. The boundaries of the pituitary gland in 7 sagittal sections and 2 axial sections were displayed three-dimensionally. The boundaries of the brain tumor, ventricles and brain were extracted well by the image processing techniques. This method may provide valuable diagnostic and physiologic information.