Software now provides the ability to perform a variety of image creation and processing functions with CT and MRI image data. With conventional CT or MRI examination, images are obtained in relatively thick slices of 5 or 10 mm. Contiguous CT or MRI slices (there is no gap between images) are obtained and are only 1 to 2 mm thick. After the images are acquired, they are transferred to a computer workstation where all anatomic structures not related to the area of interest are removed from the image. The computer software puts all the slices together to reconstitute the body part in three dimensions. This process is currently utilized for a number of applications including the face, jaw, joints, spine, and brain. The structures can be rotated to permit viewing of all surfaces and resliced in any direction to reveal deep structures or lesions.

33. CT 3-dimensional reconstruction of Egyptian mummy, bird's eye view. Courtesy of the Department of Radiology, UIHC.

Surgeons may use 3-D reconstruction for planning tumor removal, reconstruction of facial and spinal abnormalities, and verifying location of other lesions. Radiation oncology relies heavily on 3-D techniques to orient beams for radiation treatments. Investigators in psychiatry, including Drs. Andreasen, Kathol, and Robinson, are correlating 3-D images of P.E.T. scans with MRI to study brain abnormalities seen in psychiatric patients. Cardiologists and cardiac surgeons are studying heart structures with 3-D techniques.

Dr. Hanna Damasio, UIHC neurologist, utilizes this technology to investigate brain function by correlating a given damaged area of the brain with failures shown on specific neuropsychological tests (for example, the failure to recognize human faces but the capacity to recognize objects). 3-D permits her to pinpoint the location of the damage and obtain as much detail as possible. A special program of Dr. Damasio's allows color coding of grooves (sulci) on the brain surface, so that dots of the same color identify the groove on any projection.

34, 35. CT 3-dimensional reconstructions of the vertebral column. Courtesy of the Department
of Radiology, UIHC