Although knowledge about the myocardial mass (in grams) of the different territories belonging to the major coronary arteries, is of clinical importance to estimate risk of coronary interventions (PCI, CABG) and to determine area of necrosis after myocardial infarction, no invasive methodology has been available so far for reliable assessment of mass.~Especially in the setting of percutaneous coronary intervention (PCI), it would be valuable to have information about the absolute and relative myocardial mass distal to the location where the intervention is planned. Such information is valuable for risk estimation and can also be helpful in multivessel disease to determine the most adequate way of revascularization.~Both MRI and CT scanning have claimed to be able to estimate myocardial mass non-invasively, but by the lack of any gold standard, none of these methods could be validated in vivo so far.~A relatively new development in CT technology is the calculation of fractional flow reserve (FFR) by CT scanning, according to a sophisticated algorithm developed by Heartflow Inc. One of the baseline assumptions in that algorithm is that myocardial mass is proportional to resting blood flow, which seems a plausible assumption from a rational physiological point of view.~More recently, invasive calculation of absolute blood flow has become possible as well as resistance measurement of the (microcirculation of the) myocardium.~Using that invasive technology (explained in the appendix to this protocol), it can be assumed that measuring absolute maximum blood flow in a coronary artery as well as fractional flow reserve for different territories or for different spots within one major coronary artery, provides a basis for relative mass calculation. The background for performing the present study is to compare these mass calculations by CT scanning and by invasive measurements, thereby corroborating both methods.
The background for performing the present study is to compare the mass calculations by CT scanning and by invasive absolute blood flow measurements and thereby corroborating both methods.