Investigation by Computed Tomography and Magnetic Resonance

Abstract

The first CT scanners produced axial data only, and each image took minutes to acquire and reconstruct. Recent advances have resulted in spiral or helical scanning, which generate a volume of data (see Chakraborty S, Nakielny R A, Surgery 2002; 20(10): i-ii). This means that images can be reconstructed in any plane. The latest version of this is the multislice scanner, which enables a reduction in time of scanning, section thickness and respiratory mis-registration. Reformats in coronal and sagittal planes are now possible with resolution equal to the axial source images and even non-planar reformats are possible. The whole of the chest, abdomen and pelvis can be imaged in less than 1 minute. An added advantage is the ability to obtain optimal opacification of vessels with intravenously administered contrast medium, producing angiograms of equal quality to conventional angiography. Multislice scanning generates a very large number of sections, making it impractical to image every section. Hence, most imaging departments review the images from workstations and produce only selected hard-copy. This implies a requirement for closer contact between clinicians and radiologists.