A system integrated with a 1st generation computed tomography (CT) head [human] scanner was described. With the assistance of an additional program and minimal hardware changes, it was possible to examine specific areas on the preinfusion studies and obtain instantaneous printouts of a number of parameters including mean densities. This measurement technique was then applied to the preinfusion scans of lucent lesions, abscesses and glioblastomas, and dense lesions, recent hemorrhages, some uncalcified meningiomas and some metastatic melanomas. These 5 lesions had characteristic mean attenuation values that seemed to allow classification of each of the 5 entities. Hardware and software changes were described, and practical application of the system was discussed.