Fundamentals of multichannel CT.

Abstract

Multichannel computed tomography (MCCT) has created a technical revolution in CT scanning. Following the introduction of single-channel helical scanning in 1989, 4-channel systems were introduced in 1998 and 16-channel systems in 2002. The core of this new technique is the X-ray detector array design, which allows for multiple simultaneous registration of slice information during gantry rotation. This design allows for faster scanning and acquisition of thinner slice widths. The high-speed scanning also minimizes motion artifacts. The ability to scan with very thin slice thickness creates a scanned volume with isotropic voxels. This allows for two- and three-dimensional reconstructions with similar resolution as the source images. MCCT also allows for higher X-ray tube currents, which create better penetration of metallic orthopedic fixation devices. Musculoskeletal imaging benefits from MCCT because large anatomic areas may be covered with thin slices. When needed, high tube currents can be applied for scanning areas of interest in the presence of metal. Thin slice acquisition allows isotropic viewing, which we use routinely.