Computed tomography: Overview

Abstract

The development of computed tomography (CT), resulting in widespread clinical use of CT scanning by the early 1980s, was a major breakthrough in clinical diagnosis across multiple fields. The primary advantage of CT was the ability to obtain thin cross-sectional axial images, with improved spatial resolution over ultrasound, nuclear medicine, and magnetic resonance imaging. This imaging avoided super-position of three-dimensional (3D) structures onto a planar 2D representation, as is the problem with conventional projection X-ray (fluoroscopy). CT images, which are inherently digital and thus quite robust, are amenable to 3D computer reconstruction, allowing for ultimately nearly an infinite number of projections. From a cardiac perspective, the increased spatial resolution is the reason for its increase in sensitivity for atherosclerosis, plaque detection, and coronary artery disease (CAD). With CT, smaller objects can be seen with better image quality. Localization of structures (in any plane) is more accurate and easier with tomography than with projection imaging like fluoroscopy. The exceptional contrast resolution of CT (ability to differentiate fat, air, tissue, and water), allows visualization of more than the lumen or stent, but rather the plaque, artery wall, and other cardiac and noncardiac structures simultaneously. © 2010 Springer-Verlag London Limited.