DIFFERENTIATION OF NEOPLASTIC FROM NON‐NEOPLASTIC LESIONS IN DOG BRAIN USING QUANTITATIVE CT

Abstract

The uptake and washout of iodinated contrast medium in neoplastic and non‐neoplastic lesions in the dog brin was quantified using computed tomography. The magnitude of tissue contrast enhancement was measured during and up to 15 minutes following an intravenous infusion of contrast medium. Compartmental analysis was used to obtain rate contants for contrast medium movement into and out of brain lesions. In non‐glioma tumors, contrast enhancement was maximum during the infusion and the rate of contrast washout was comparable to that measured in the normal brain. Mixed gliomas also showed maximum enhancement during infusion, but there was no washout of contrast. Contrast enhancement in radiation‐induced brain damage and cystic encephalomalacia secondary to tumor compression continued to increase for 5–15 minutes after infusion; rate constants in these non‐tumor lesions were different from all tumors studied. Hyperthermia‐induced lesions had comparable rate constants for contrast washin and washout. These results indicate that kinetic CT studies provide a non‐invasive measure of permeability differences between lesions, may be useful in differentiating certain types of intracranial lesions, and may provide an effective method for patient follow‐up after treatment.