Interpretation of the computerized tomographic scan.

Reprint requests to: Dr. M. Banna, Department of Radiology, McMaster University Medical Centre, 1200 Main Street West, Hamilton, Ontario Canada L8S 4J9. INTRODUCTION The principles of computerized tomography have been outlined in a previous publication (Banna and Porteous, 1976). The present paper describes our experience with the scan in various intracranial lesions. Our findings correlate well with others (Davis and Pressman, 1974; Paxton and Ambrose, 1974). In this paper a tissue is described as either of high or low density relative to the surrounding brain. The normal appearances are shown in Figure 1. Intracranial lesions may be broadly classified into two categories. A. High density lesions: These include any type of intracranial calcification, hemorrhage, giant aneurysm, benign tumors such as meningioma, neurofibroma, pituitary adenoma and a minority of malignant intracranial neoplasms. B. Low density lesions: These include all fat containing tumors such as lipoma, cholesteatoma and craniopharyngioma, cystic lesions within or outside the brain, and the majority of malignant neoplasms and cerebral infarctions or edema. Each of these will be separately considered.