Cardiac computed tomography

Diseases of the heart and blood vessels represent one of the most challenging problems for advanced diagnostic imaging systems. Not only do these diseases represent the major medical problem of our time in terms of death, acute and chronic illness, and disability, but cardiac diagnosis involves complex technical difficulties due to rapid motion and the complex structure of the heart and cardiovascular system. Computerized-tomographic scanning is potentially an ideal cardiac imaging modality since CT is a cross-sectional imaging method with potentially very high resolution. Currently available CT scanners have exposure speeds in the range of 1-5 s, a speed that is inadequate for the majority of cardiovascular imaging applications. Nevertheless, a variety of limited CT scanning techniques have been successfully applied to selected imaging problems. These methods involve the use of contrast media injected into the blood combined with either dynamic CT scanning or gated CT scanning. Currently advanced CT scanners permit visualization of major coronary arteries, imaging of normal and ischemic myocardium, and quantitation of the volumes of the major cardiac chambers. Fast, multiple-slice CT scanners are actively under development. No-motion, electronic scanning using scanning electron-beam techniques represents a promising approach to high-speed fully three-dimensional CT scanning. The CVCT scanner, under development at the University of California, San Francisco, will image up to 8 contiguous slices at a rate of 36-54 images per second. The technical feasibility of the CVCT has been demonstrated using a testbed simulation of the scanning-beam configuration. The completed prototype scanner is expected to be available for testing early in 1983.