Current status of mechanical computed tomography in cardiac imaging.

Mechanical computed tomography (CT) scanners have undergone significant improvements in their ability to perform cardiac imaging. Previously limited by cardiac motion artifacts and slow acquisition speeds, newer-generation scanners are able to obtain multiple slices with a temporal resolution of <100 msec, minimizing motion artifacts to levels comparable to electron-beam computed tomography (EBCT). This is done using various approaches, including (1) prospective and retrospective electrocardiographic gating, (2) multislice detectors, and (3) partial and segmented reconstruction algorithms. The major CT manufacturers are putting significant resources into protocol optimization and cardiac applications development, including coronary calcium quantification, functional analysis, and coronary CT angiography. Given the rapid pace of development, higher in-plane and z-axis spatial resolution, and superior signal-to-noise ratio of mechanical scanners, it is evident that they will be capable of performing cardiac imaging with a quality approaching or possibly surpassing that of existing EBCT scanners. This article summarizes the current status of mechanical CT scanners in cardiac imaging.