Comparison of tumor blood by perfusion assessed by dynamic contrast-enhanced MRI with tumor blood supply assessed by invasive imaging

Abstract

Purpose: To evaluate the potential of Gd-DTPA-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for providing high-resolution tumor blood perfusion images. Materials and Methods: Xenografted tumors from two amelanotic human melanoma lines (A-07 and R-18) were used as preclinical models of human cancer. DCE-MRI was performed at a voxel size of 0.5 X 0.2 X 2.0 mm3 with the use of spoiled gradient recalled sequences. We produced tumor images of E·F (where E is the initial extraction fraction, and F is perfusion) by subjecting the DCE-MRI data to Kety analysis, and then compared those images with images of tumor blood supply. We obtained high-resolution tumor blood supply images using the Bioscope silicon strip detector system to measure the uptake of Na99mTcO4 in histological preparations. We assessed the global blood supply by measuring the tumor uptake of three freely diffusible blood flow tracers: 86RbC1, [14C]IAP, and Na99mTcO4. Results: E·F was found to mirror the blood supply well in A-07 and R-18 tumors. The mean E·F differed between the A-07 and R-18 tumors by a factor of ∼1.6, and this difference was similar to the difference in the global blood supply. The intratumor heterogeneity in E·F was significant for tumors of both lines, and this heterogeneity was similar to the intratumor heterogeneity in the blood supply. The Intratumor heterogeneity in the blood supply differed slightly between the A-07 and R-18 tumors, and even this difference was mirrored by the E·F images. Conclusion: E·F images of xenografted tumors reflect blood perfusion. This implies that E·F may be a useful parameter for Improving cancer diagnostics and individualizing cancer treatment. This possibility deserves to be investigated thoroughly in clinical studies. © 2005 Wiley-Liss, Inc.