Projected electronic dissection (PED) creates the effect of actually dissecting a tissue structure under examination by operating on a 3-D digitized data set. Advanced computer techniques have made it possible to range through a 3-D MRI (magnetic resonance image) data set in real time. In actual dissection, however, if a portion of a volume is sliced off, is it possible to see both the remaining external surface and any internal surfaces revealed by the removal of superficial layers. PED refers to a technique that displays not only tissue paraenchyma at the level of cut, but also these internal and external surfaces, which can be important both for orientation and diagnosis. Preliminary PED results were obtained on MRI volumetric data set of proton densities of the brain. The initial results suggest that the partial shaded projection technique described offers the prospect of providing a natural way to display and analyze experimental data from the brain and other organ systems with applications in medical diagnosis, the study of anatomy and the planning of surgery.<<ETX>>