Computer Assisted Mapping in Quantitative Analysis of Cerebral Positron Emission Tomograms

An interactive FORTRAN program was developed to provide a time saving mapping procedure with high, largely user-independent reproducibility and flexible adaptation to individual anatomical variations, and discrimination between gray and white matter is in good agreement with theoretical predictions.

Abstract

For quantitative analysis of CT of the brain, an interactive FORTRAN program was developed to provide a time saving mapping procedure with high, largely user-independent reproducibility and flexible adaptation to individual anatomical variations. Program scope and functions are demonstrated, and results obtained in a group of seven normal volunteers are presented for positron emission tomography using the [18F]-2-fluoro-2-deoxy-D-glucose (FDG) method. Basically, the procedure is designed as a two step process: first, a region raw contour is defined geometrically on the basis of local Cartesian or polar coordinates relative to the whole brain contour; second, the final region is delimited within the raw region, in the FDG images according to relative local tissue activity. Although all parameters for mapping a brain slice are stored in a standard parameter file ensuring reproducibility and comparability, interactive control of all steps permits user-guided corrections whenever necessary. Numerical results closely correspond to the data obtained in a previous study of normal subjects with individual manual mapping; discrimination between gray and white matter is in good agreement with theoretical predictions. The program can be easily adapted to other CT techniques.