Colorectal Tumor Vascularity: Quantitative Assessment with Multidetector CT--Do Tumor Perfusion Measurements Reflect Angiogenesis?

doi:10.1148/radiol.2492071365

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Gastrointestinal Imaging

Colorectal Tumor Vascularity: Quantitative Assessment with Multidetector CT—Do Tumor Perfusion Measurements Reflect Angiogenesis?¹

Vicky Goh, MA, MRCP, FRCR, Steve Halligan, MD, FRCP, FRCR, Frances Daley, MSc, David M. Wellsted, PhD, Thomas Guenther, MD, PhD, and Clive I. Bartram, FRCP, FRCS, FRCR

¹ From the Paul Strickland Scanner Centre (V.G.) and Gray Cancer Institute (F.D.), Mount Vernon Hospital, Northwood, Middlesex, England; Department of Academic Radiology, University College Hospital, 235 Euston Road, Level 2 Podium, London NW1 2BU, England (S.H.); Health Research and Development Support Unit, University of Hertfordshire, Hatfield, England (D.M.W.); and Academic Department of Histopathology (T.G.) and Intestinal Imaging Centre (C.I.B.), St Mark's Hospital, Harrow, England. From the 2006 RSNA Annual Meeting. Received August 7, 2007; revision requested October 29; revision received January 25, 2008; accepted March 26; final version accepted May 19. Supported in part by a pump-priming grant from the Royal College of Radiologists, United Kingdom. Address correspondence to S.H. (e-mail: s.halligan{at}ucl.ac.uk).

Purpose: To establish the relationships between quantitative perfusioncomputed tomography (CT) parameters—specifically, primary tumorblood flow, blood volume, transit time, and permeability surface-areaproduct—and immunohistologic markers of angiogenesis in colorectalcancer.

Materials and Methods: After institutional review board approvaland informed patient consent were obtained for this prospective study,23 patients (11 men, 12 women; mean age, 68.4 years; age range, 34.8–87.1years) with colorectal adenocarcinoma underwent a 65-second perfusionCT examination, and tumor blood flow, blood volume, mean transittime, and permeability surface-area product were determined. Aftersurgery, resected specimens were sectioned and stained immunohistochemicallyto identify CD34 for quantification of microvessel density (MVD),to identify smooth muscle actin for assessment of pericyte coverageindex, to identify vascular endothelial growth factor (VEGF), andto identify glucose transporter protein (GLUT-1). Perfusion CT measurementswere correlated with MVD, pericyte coverage index, VEGF expression,and GLUT-1 expression by using Pearson or Spearman rank correlationanalysis, with significance assigned at the 5% level.

Results: Mean blood flow, blood volume, transit time, and permeabilitysurface-area product values were 72.1 mL/min/100 g of tissue ±28.4 (standard deviation), 6.2 mL/100 g of tissue ± 1.4, 9.3seconds ± 3.9, and 13.9 mL/min/100 g of tissue ± 3.2,respectively. Blood volume (r = 0.59, P = .002) and permeabilitysurface-area product (r = 0.46, P = .03) correlated positively withMVD, but blood flow (r = 0.27, P = .22) and transit time (r = –0.18,P = .44) did not. There were no significant associations betweenany perfusion CT parameter and pericyte coverage index (r $≤$ 0.36,P > .05), VEGF score ( ${rho}$ $≤$ 0.30, P $≥$ .15), or GLUT-1 score ( ${rho}$ <0.21, P $≥$ .33).

Conclusion: Tumor permeability surface-area product and blood volumecorrelate positively with MVD and may reflect the microvascularityof colorectal tumors.