FN13762 Murine Breast Cancer: Region-by-Region Correlation of First-Pass Perfusion CT Indexes with Histologic Vascular Parameters

To investigate the correlation between first-pass perfusion computed tomographic (CT) indexes and histologic vascular parameters in FN13762 breast cancer in rats by using region-by-region correlation methods.The Animal Care and Use Committee approved this study. FN13762 murine breast cancer cells were implanted in 14 female Fischer 344 rats, and first-pass perfusion CT was performed. CT perfusion maps depicting blood flow, blood volume, mean transit time (MTT), and permeability-surface area (PSA) product were generated by using commercial perfusion software. The entire tumor area was divided into six separate regions on perfusion maps, and the regional perfusion indexes were quantified. Histologic vascular parameters, including microvessel density (MVD), luminal vessel number, luminal vessel area, and luminal vessel perimeter, were measured in the histologic region corresponding to the perfusion maps. Correlation analysis was performed between regional tumor perfusion indexes and histologic vascular parameters of the corresponding tumor region. Additionally, mean perfusion values of the entire tumor were correlated with histologic vascular parameters of the hot spot within the tumor. Among 14 rats, four were excluded from the analysis, and results were based on a final total of 10 rats.In tumors, blood flow, blood volume, and PSA product were significantly higher and MTT was significantly shorter (P < .05 for all) than these values in normal neck muscles. At region-by-region correlation, regional blood flow (r = 0.476), blood volume (r = 0.348), and MTT (r = -0.506) were significantly correlated with MVD in the corresponding tumor region (P < .01 for all). After adjustment for biologic variability between rats, regional blood flow (r = 0.614), blood volume (r = 0.515), MTT (r = -0.524), and PSA product (r = 0.228) remained significantly correlated with MVD in the corresponding tumor region. Correlation analysis between CT perfusion indexes of the entire tumor and histologic vascular parameters of the hot spot did not show significant correlations (P > .05).Regional blood flow, blood volume, and MTT are significantly correlated with MVD in the corresponding tumor region.