Important things about helical CT

Spiral computer tomography (CT) is the latest advance of technology in CT. The main principle of spiral CT is continuous rotation of the system X-ray tube-detector and continuous algorithms so called linear interpolation. The most important variable parameters are collimation, table feed, pitch factor, increment and scanning time. Optimal scan timing after contrast medium injection assures excellent vascular enhancement The authors describe the direct influence of variable parameters on the quality of multiplanar reconstruction and CT angiography by direct measurements on phantom. They advice to note the important variable parameters of each spiral CT examination on the hard copy to enable good reproducibility of the study. They discuss the drawbacks and advantages of spiral CT. (authors)