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MR-derived cerebral blood volume maps: issues regarding histological validation and assessment of tumor angiogenesis. Magn Reson Med 2001 Oct;46(4):735-47 PMID: 11590650

Pubmed ID

11590650

Abstract

In an effort to develop MRI methods for the evaluation of tumor angiogenesis (new blood vessel formation), MRI-derived cerebral blood volume (CBV) information has been compared to histologic measures of microvessel density (MVD). Although MVD is a standard marker of angiogenesis, it is not a direct correlate of the volume measurements made with MRI, and therefore inappropriate for the development and validation of the MR techniques. Therefore, the goal of this study was to develop an approach by which MR measurements of CBV can be directly correlated. To this end, dynamic susceptibility contrast (DSC) MRI experiments were performed in six Fisher rats implanted with 9L gliosarcoma brain tumors. Subsequently, the circulation was perfused with a latex compound (Microfil), after which 50-microm tissue sections were analyzed for vessel count, diameter, and the fraction of area comprised of vessels. The results demonstrate that while fractional area (FA) does not provide a good measure of CBV, FA corrected for section thickness effects does. Whereas the FA in normal brain was found to be 13.03 +/- 1.83% the corrected FA, or fractional volume (FV), was 1.89 +/- 0.39%, a value in agreement with those reported in the literature for normal brain. Furthermore, while no significant difference was found between normal brain and tumor FA (P = 0.55), the difference was significant for FV (P = 0.036), as would be expected. And only with FV does a correlation with the MRI-derived CBV become apparent (r(S) = 0.74). There was strong correlation (r(s) = 0.886) between the tumor / normal blood volume ratios as estimated by each technique, although the MR-ratio (1.56 +/- 0.29) underestimated the histologic-ratio (2.35 +/- 0.75). Thus, the correlation of MRI CBV methods requires a measurement of fractional vessel area and correction of this area for section thickness effects. This new independent correlative measure should enable efficient and accurate progress in the development of MRI methods to evaluate tumor angiogenesis.

Author List

Pathak AP, Schmainda KM, Ward BD, Linderman JR, Rebro KJ, Greene AS

Authors

Andrew S. Greene PhD Interim Vice Chair, Chief, Professor in the Biomedical Engineering department at Medical College of Wisconsin
Kathleen M. Schmainda PhD Professor in the Biophysics department at Medical College of Wisconsin




Scopus

2-s2.0-0034799187   99 Citations

MESH terms used to index this publication - Major topics in bold

Animals
Blood Volume
Brain Neoplasms
Magnetic Resonance Imaging
Male
Mathematics
Neovascularization, Pathologic
Rats
Rats, Inbred F344
jenkins-FCD Prod-331 a335b1a6d1e9c32173c9534e6f6ff51494143916