Use of automated measurements of mean density as an adjunct to computed tomography

A system integrated with a first-generation computed tomography (CT) head scanner is 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, glioblastomas--as well as "dense" lesions--recent hemorrhages, some uncalcified meningiomas, and some metastatic melanomas. These five lesions had characteristic mean attenuation values that seem to allow classification of each of the five entities. Hardware and software changes are described and practical application of the system is discussed.