Multi-detector row CT: principles and practice for abdominal applications.

Abdominal imaging with multi-detector row computed tomography (CT) can be performed during short breath holds. On 16-channel multi-detector row CT scanners, the effective detector row thickness, depending on the manufacturer, is typically 1.0-1.5 mm, which results in a beam collimation of 16-24 mm. At a gantry rotation speed of 0.5 second and a pitch of 1, the table travel speed will be 32-48 mm/sec. At a smaller effective detector row thickness and a narrower beam collimation, a slightly higher pitch may be needed to obtain short-breath-hold CT scans. Typically, transverse scans are viewed at a reconstructed section thickness of 3-5 mm, with thinner sections used for CT angiography and whenever off-axial reformations are obtained. The radiologic technique should be optimized according to the transverse section thickness used for interpretation, and the contrast material administration protocol should be optimized according to the clinical problem, with the scanning triggered for enhancement of a target organ.