Contrast enhancement of spontaneous animal CNS tumors with gadolinium DTPA: a correlation of MRI with x-ray CT.

A visual comparison was made between both pre-contrast and post-contrast x-ray computerized tomographic images (X-CT) and magnetic resonance tomographic images (MRI) of spontaneous CNS tumors in three animals. The contrast agents, HypaqueR-76 (X-CT) and Gadolinium DTPA (MRI), were administered as an intravenous bolus injection. The parameters for comparison of pre- and post-contrast features included: lesion discrimination, demarcation, and intensity and pattern of enhancement. Necropsy specimens were included to correlate the anatomic fidelity of scan appearances for each modality and to establish a final diagnosis. There was good visual correlation of the lesion site with both X-CT and MRI. The intensity of lesion enhancement with the contrast reagents was similar for each modality but there were subtle differences in the pattern of enhancement. Overall, MRI in conjunction with the contrast agent Gadolinium DTPA, was as good or better at delineating the presence and extent of CNS tumors than contrast enhanced X-CT. Contrast agents may be necessary to provide increased lesion detectability and delineation when imaging with magnetic resonance.