ABSOLUTE VOLUMETRIC CORONARY BLOOD-FLOW MEASUREMENT WITH DIGITAL SUBTRACTION ANGIOGRAPHY

The problems associated with visual interpretation of coronary arterio grams have been well-documented. There is a need for more physiologic means of assessing coronary artery stenosis during routine coronary ar teriography. Volumetric coronary blood flow assessed as a function of time can be a valuable aid in the analysis of functional significance of arterial obstruction. A volumetric coronary blood flow measurement technique was investigated in a swine animal model using phase matched temporal subtraction images. The left anterior descending (LAD) coron ary artery of swine animal models were instrumented with an ultrasound flow probe (US) and a vascular occluder producing stenosis. Contrast material injections (2-4 ml/sec for 3 sec) were made into the left cor onary ostium during image acquisition. Phase-matched temporal subtract ion (DSA) images were used to measure volumetric coronary blood flow i n the LAD. In addition, a technique for automatic estimation of iodine calibration slope was also investigated. In 49 independent comparison s, the mean coronary blood flow (FPA) correlated extremely well with t he mean US flow (FPA = 0.92US + 1.42 ml/min, r = 0.99, standard error of estimate (SEE) = 4.32 ml/min). Further more, the automatic iodine c alibration technique was shown to be very accurate. In conclusion, acc urate volumetric coronary blood flow measurements can be made before t he onset of significant changes in coronary blood flow due to contrast injection.