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 assessment of treatment effectiveness. The goals of our study were to measure percent vascular volume in two experimental tumor sublines using F-19 magnetic resonance imaging (MRI) and to assess changes in tumor blood volume with growth. METHODS. An emulsion of perfluorotributylamine (FTBA) was used as a vascular contrast agent for F-19 MRI. The amount of emulsion in the tumor vasculature was measured by F-19 MRI and used to calculate percent vascular volume. A separate ex-vivo study of vascular volume was conducted using the dye Hoechst 33342. A total of rive rats were studied by MRI and 14 by the ex-vivo method. RESULTS. The ranges of percent vascular volume values measured in the imaging and Hoechst dye studies were 2% to 9% and 1.25 to 7%, respectively. A trend toward decreasing percent vascular volume with increasing tumor volume was evident in one tumor subline. CONCLUSIONS. The quantitative F-19 MRI technique was effective for measuring percent vascular volume and changes in vascular volume with growth.