Visual interpretation of the x-ray coronary arteriogram is today the gold standard for defining the pathoanatomy in coronary heart disease. There are inherent limitations, however, in this method of interpretation. In particular, arterial flow rates are needed to estimate the degree of regional insufficiency of blood supply. Despite the arteriogram's central role it permits only indirect and crude estimates of flow rates. Efforts to use the 'time-of-flight' method to estimate x-ray dye flow rates have not been successful clinically. The procedure is complex and has been limited to the less informative projective images. This proposal is to implement a direct automated measurement technique to evaluate regional muscle perfusion in 3-D. The new technique utilizes the x-ray projection angiographic data. However, rather than reconstructing in 3-D the initial phase of the injection of the contrast dye, the late portion of the injection is reconstructed. This late phase exhibits large pulsatile levels of contrast dye in the sponge-like muscle. From the pulsatile rates of clearance and re-supply of the dye, and the magnitude of these pulses, relative flow rates and muscular contractility are computed in 3-D. These important cardiac parameters have been elusive so far. Their measurement constitutes an important innovation for the goal of this effort to improve the choice of therapy in coronary heart disease and immediate decision while doing PTCA.
