What is the state-of-the-art method to calculate intravascular perfusion parameters in contrast-enhanced CT?
I want to create perfusion metric maps of the pulmonary vascular tree, but, in literature, it isn‘t clear to me which is the „state-of-the-art“ method for this. My target metrics are blood flow, blood volume and mean transit time.
I understand that, in the field of blood kinetics, the choice falls between two types of methods:
- Deconvolution-based methods - a one-compartment model is assumed with an input and an output flow. The compartment represents a region in space enclosing perfused tissue and its respective capillary vasculature. The input represents blood being supplied by an artery, and the output, blood being drained to a vein. In practice, the compartment is an ROI of voxels in organ tissue, the input an ROI in a major artery, and the output an ROI in a major vein. Through Fick‘s principle it was derived that the mentioned metrics can be calculated from the impulse response, which is obtained by the deconvolution of the concentration curve (average pixel time-intensity in ROI) of the arterial ROI (arterial input function) and the tissue‘s ROI.
- Non-deconvolution-based methods - metrics get calculated directly from the concentration curves, as derived by the conservation of mass principle applied to a bolus passing through an ROI of interest. Here, there is a bolus being supplied into and drained out of an interest volume. As above, the supply is an artery and the drain is a vein. Blood flow then gets calculated by the maximum slope method, and blood volume gets calculated by the ratio of the areas under curve of the arterial and venous concentration curves.
Repeating both methods for a number of ROIs yields metric maps. However, they always assume an arterial and venous input and output, as well as a compartment where the blood gets „deposited and withdrawn“.
Is it reasonable at all to use the same rationale for vessels? More precisely, the curve concentration of an initial segment of the vessel would serve as input, a second segment as compartment, and a third segment as output. And repeating this procedure would eventually lead to mapping the entire vessel tree. I haven‘t seen this applied in literature - am I missing some important assumption that‘s unreasonable in the intravascular case?
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source https://www.reddit.com/r/Radiology/comments/roliup/what_is_the_stateoftheart_method_to_calculate/
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