Evaluation of coronary anatomy using high-speed volumetric computed tomographic scanning

Although coronary angiography involves minimal risk, it is sufficiently invasive that symptoms suggestive of myocardial ischemia are usually needed before the procedure is indicated, and presymptomatic patients in an at-risk group generally do not undergo catheterization. A practical method for obtaining coronary anatomy is computed tomographic (CT) scanning of contrast-filled coronary arteries. To visualize the epicardial coronary branches, a 3-dimensional (volume) CT image must be generated that contains the entire coronary tree, and the volume must be scanned fast enough to minimize image blurring and distortion due to cardiac motion. These features are available with the dynamic spatial reconstructor (DSR). In this report, we describe our initial use of the DSR to evaluate coronary anatomy from a single selective contrast medium injection into the left coronary artery. The DSR is a prototype instrument (Fig. 1) capable of scanning a 3-dimensional volume 21.5 cm in length and in diameter in 0.01 second and at a rate of 60 times/s. It contains 14 x-ray sources with 14 corresponding video based imaging chains. The x-ray tubes and image chains are mounted on a rotating turret (15 rpm) and are pulsed sequentially to provide 12-degree increments in viewing angle around the semicircular scanning arc. Detailed description of the DSR has been provided in previous studies.^1-3.