Quantitative tumor perfusion assessment with multidetector CT: are measurements from two commercial software packages interchangeable?

Abstract

To prospectively determine the level of agreement between tumor blood volume and permeability measurements obtained with two commercially available perfusion computed tomographic (CT) software packages. This study was performed with institutional review board approval; informed consent was obtained from all participants. A total of 44 patients (24 men, 20 women; mean age, 68 years; range, 28-87 years) with proved colorectal cancer were examined prospectively with multi-detector row CT. A 65-second tumor perfusion study was performed after intravenous bolus injection of contrast material. Tumor blood volume and permeability were determined with two methods: adiabatic approximation of distributed parameter analysis and Patlak analysis. Agreement between the results was determined by using Bland-Altman statistics. Within-patient variation was determined by using analysis of variance. The mean values for permeability and blood volume, respectively, were 13.9 mL x 100 mL(-1) x min(-1) +/- 3.7 (standard deviation) and 6.1 mL/100 mL +/- 1.5, as calculated with distributed parameter analysis, and 17.4 mL x 100 mL(-1) x min(-1) +/- 7.3 and 10.1 mL/100 mL +/- 4.2, as calculated with Patlak analysis. The mean difference and 95% limits of agreement, respectively, were -3.6 mL x 100 mL(-1) x min(-1) and -18.4 to 11.2 mL x 100 mL(-1) x min(-1) for permeability and -3.9 mL/100 mL and -10.9 to 3.0 mL/100 mL for blood volume. The coefficient of variation was 37.4% for permeability and 46.5% for blood volume. There was disagreement between the methods used to estimate tumor vascularity, which indicated the measurement techniques were not directly interchangeable.