Measurement of blood‐brain barrier permeability in a tumor model using magnetic resonance imaging with gadolinium‐dtpa

Abstract

Sequential MR imaging with gadolinium‐diethylenetriaminepentaacetic acid (Gd‐DTPA) and sequential measurements of plasma Gd‐DTPA concentration by inductively coupled plasma atomic emission spectroscopy (ICP‐AES) were used to estimate the blood‐to‐tissue transport coefficient (K_i) in the 36B‐10 rat glioma model. For these measurements, tissue Gd‐DTPA concentration was estimated from tumor enhancement by correlation with calibration measurements obtained by ICP‐AES analysis of tumor tissue. The 14 animals for which K_i, was calculated can be grouped into those imaged at 11 days following tumor implantation, at 13‐18 days, and at 20 days. The mean (+SEM) K_i values for these groups were 1.1 + 0.24, 9.2 + 0.8, and 13.4 + 1.7 ml/kg‐min, respectively. These results correspond well with published data obtained by quantitative autoradiography. It is concluded that frequent sequential imaging and a graphical approach to K_i, calculation are promising methods for determining the blood‐to‐tissue transport coefficient noninvasively by contrastenhanced MRI.