What is CT Perfusion?

Perfusion is the delivery of blood through the arterial system and capillaries to the tissue and it can be calculated by various techniques with different units. In large vessels, blood flow is measured as a velocity, but in the capillary bed perfusion is calculated as the volume of blood delivered to a volume of tissue at a given time (mL/min/100 mL) [5].

CT Perfusion requires administration of iodine contrast and dynamic image acquisition covering the structures of interest. In the absence of image artifacts, there is a linear correlation between the measured x-ray attenuation and the iodine concentration, which makes the mathematical modeling straightforward. By subtracting the initial unenhanced image, it is possible to create tissue attenuation curves voxel by voxel. It is important to take into consideration that iodine contrast is not a strict intravascular agent, so the enhancement represents both intravascular contrast and contrast in the extracellular space.