Objective: To determine the effect of acquisition time on quantitative colorectal cancer perfusion measurement. Methods: Dynamic contrast-enhanced computed tomography (CT) was performed prospectively in 10 patients with histologically proven colorectal cancer using 4-detector row CT (Lightspeed Plus; GE Healthcare Technologies, Waukesha, WI). Tumor blood flow, blood volume, mean transit time, and permeability were assessed for 3 acquisition times (45, 65, and 130 seconds). Mean values for all 4 perfusion parameters for each acquisition time were compared using the paired t test. Results: Significant differences in permeability values were noted between acquisitions of 45 seconds and 65 and 130 seconds, respectively (P = 0.02, P = 0.007). There was no significant difference for values of blood volume, blood flow, and mean transit time between any of the acquisition times. Conclusions: Scan acquisitions of 45 seconds are too short for reliable permeability measurement in the abdomen. Longer acquisition times are required.
