MEASUREMENT OF VASCULAR VOLUME IN EXPERIMENTAL RAT-TUMORS BY F-19 MAGNETIC-RESONANCE-IMAGING

RATIONALE AND OBJECTIVES. In-vivo assessment of tumor vascular volume may provide useful information for treatment planning or the assessmen t of treatment effectiveness. The goals of our study were to measure p ercent vascular volume in two experimental tumor sublines using F-19 m agnetic resonance imaging (MRI) and to assess changes in tumor blood v olume with growth. METHODS. An emulsion of perfluorotributylamine (FTB A) was used as a vascular contrast agent for F-19 MRI. The amount of e mulsion in the tumor vasculature was measured by F-19 MRI and used to calculate percent vascular volume. A separate ex-vivo study of vascula r volume was conducted using the dye Hoechst 33342. A total of rive ra ts were studied by MRI and 14 by the ex-vivo method. RESULTS. The rang es of percent vascular volume values measured in the imaging and Hoech st dye studies were 2% to 9% and 1.25 to 7%, respectively. A trend tow ard decreasing percent vascular volume with increasing tumor volume wa s evident in one tumor subline. CONCLUSIONS. The quantitative F-19 MRI technique was effective for measuring percent vascular volume and cha nges in vascular volume with growth.