3-D Image Processing In Functional Stereotactic Neurosurgery
Giacomo Garibotto, C. Giorgi, U. Cerchiari · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1983
The possibility of analyzing neuroanatomical images (such as in computerized tomography) in a three dimensional form represents a significant improvement in diagnostic accuracy over conventional analysis of 2-D images. Expecially when the task consists in finding correspondences and/or differences between different measures of the same organ, only a 3-D comparison allows reliable results avoiding misregistration errors. In the paper we refer an example of 3-D analysis and representation of cerebral structures in functional stereotactic neurosurgery. This problem is briefly introduced in section 1, with reference to the state of the art and future trends of the medical research. Digital image processing techniques are used to obtain a 3-D description of some diencephalic structures, primarily involved in stereotactic neurosurgery. The input data consist in parallel sections of suitably stained brain slices which are displayed in a stereotactic atlas 11] . The 3-D reconstruction has been accomplished in different steps : at first the contour lines of the cerebral structures have been digitized as a 1-D description of the cerebral structures. Then a contour filling procedure has been implemented to collect these elements in a finite number of regions,labelled by fixed amplitude values (easy discrimination using pseudocolor display).Due to the non-uniform spacing of the atlas sections, three-dimensional interpolation has been performed on such 2-D images. These processing techniques are described in section 2, with examples of application on actual stereotactic data. The main advantage of dealing with neuroanatomical data in 3-D form is the possibility to verify any probe trajector that does not lie in the atlas planes, which is usually the case. Very simple techniques have been developed to evaluate arbitrarily slant sections of the volume as well as to obtain approximate 3-D assonometric display, using standard minicomputer [21 . A brief discussion on these solution is referred in section 3.