Evaluation of computed tomography in oncology.

An evaluation was made of 1343 CT scans performed at The Princell Margaret Hospital using a 20-second body scanner. Six patient groups were defined according to the clinician's objective in ordering the scan, and to the relevance of symptoms to the region scanned. Computer-assisted analysis revealed that only by dividing patients into categories using three parameters (scan region, primary diagnosis and clinician's objective) did significant differences in the ratio of normal to abnormal CT scan results become apparent. Very specific groups of patients for whom CT is a low-yield procedure could be identified; nevertheless, further investigation showed that a normal CT result was of benefit in the management of these patients. The overall use of CT was efficacious and low diagnostic yield alone is not a sufficient measure of inappropriate use of CT.