HELICAL CT - PRACTICAL CONSIDERATIONS AND POTENTIAL PITFALLS

Helical (spiral) computed tomography (CT) is having a dramatic impact on body imaging. Unlike conventional CT, helical CT provides continued volumetric acquisition as the patient moves through the gantry. Advan tages of helical CT include dramatically shortened examination times, improved visibility of vascular structures; better enhancement of pare nchymal organs, the capability for retrospective imaging and three-dim ensional (3D) vascular studies, and potential reduction in use of cont rast material. However, helical CT requires one to be more cognizant o f the relationship between contrast material administration and scanni ng, since the optimal temporal window for detection of disease can be missed. Factors unique-to helical technology can produce artifacts, wh ich one must be aware of when interpreting helically generated scans. Many of these artifacts relate to accentuation of vascular or parenchy mal enhancement. Others occur during production of high-quality 3D ima ges. Additional artifacts are sure to be identified with increased exp erience with helical CT.