<title>Densitometric determination of the flow distribution in the bifurcation of the left coronary artery</title>

Abstract

The long term goal of this research is to determine the clinical relevance of stenosis. Where most QCA algorithms calculate the decrease in lumen from one angiocardiogram, we seek to determine directly the influence of the stenosis on the blood flow. The method uses only a slightly different clinical approach as compared to 'traditional' noninterventional catheterizations. Instead of injecting a steady flow of contrast agent, we propose to inject a string of small droplets. The resulting string of droplets will enable us to estimate the relative blood flow by measuring their time of arrival in some designated regions. Repeating the same procedure after administering a vasodilative drug, we obtain a relative decrease (or less increase) in blood flow in one of the two distal branches of the bifurcation due to the presence of stenosis. From the resulting X-ray image sequence multiple frames are selected, and the information is combined to find the relative blood velocity. The conclusion is that it is possible to use sequences of images instead of just one image to calculate quantitative results. Major problems to overcome are the respiratoryand heart-motions, and differences in acquisition parameters between runs. The usefulness of the new method in real clinical applications and the coherence with other measures are currently under trial.

X-ray videodensitometric methods for blood flow and velocity measurement: A critical review of literature

“…The resulting bolus transport time method, usually known as mean bolus transport time, was used to determine blood flow in human internal carotid arteries, 26,28 in porcine 61 and human intracranial aneurysms, 28 in canine 62,63 and human coronary arteries, 30,[64][65][66]67 in major canine 32,46,47,[68][69][70][71][72][73] and human arteries, 15,31,35,59,[74][75][76][77][78][79][80] in in vitro flow phantoms 26,31,32,35,41,60,69,70,74,79,[81][82][83][84] and for measurement of canine 85,86 and human regional coronary blood flow ͑myocardial perfusion͒. 37,40,[86][87]…”

Digital densitometric determination of relative coronary flow distributions

“…However, the correctness of the method has not been evaluated yet. it must also be noted that the method may incorrectly yield a negative outcome when both arteries distal to the bifurcation exhibit stenoses (SCHRIJVER et al, 1999). …”

“…where the subscripts rb and lb denote right branch and left branch, respectively (SCHRIJVER, 1999). it should be noted in eqn 2 that it is assumed that the cross-sectional areas in the left and the right branch, Alb and A,.b, respectively, are the same.…”

Coronaries, x-ray imaged, clinical development

“…However, the correctness of the method has not been evaluated yet. It must also be noted that the method may incorrectly yield a negative outcome when both arteries distal to the bifurcation exhibit stenoses (Schrijver, 1999).…”

“…where the subscripts rb and lb denote right branch and left branch respectively (Schrijver, 1999). It should be noted in Equation 13.2 that it is assumed that the cross-sectional areas in the left and the right branch, A lb and A rb respectively, are the same.…”