Pulsatile coronary flow determination by digital angiography.

A new angiographic method to calculate absolute coronary arterial blood flow and its cyclic variations as a function of time, has been designed and evaluated. The method combines densitometric analysis of spatial and temporal aspects concerning the contrast propagation through the arterial system from digital images, and is based on applying the concept of conservation of contrast material in successive images. It requires a standard arteriographic procedure. In simulations with both constant as well as pulsatile flow through a coronary arterial phantom, an excellent agreement with electromagnetic flow measurements was demonstrated (r = 0.993 and r = 0.982, respectively). Preliminary clinical results show, that the method yields reproducible assessment of coronary flow patterns after repeated injections in a patient. In a coronary artery bypass graft, coronary flow patterns in a baseline and a drug-induced hyperemic state were obtained. A consistent coronary flow reserve value was determined after repeated examinations. The method has been shown to be feasible in clinical applications, uncomplicated and fast, but requires further animal and clinical validation in order to determine the possible applications, limitations and accuracy.