Evaluation of ultrafast CT scanning of the adult abdomen.

Abstract

Various measures of image quality were compared from adult abdomen scans obtained with a subsecond computed tomographic (CT) scanner (Imatron Ultrafast C-100) and a conventional third-generation whole-body scanner (GE9800). Forty images from 13 patients scanned within 2 hours of each other on both scanners were evaluated with techniques standardized as much as possible for CT exposure factors and contrast enhancement. Two observers in consensus evaluated matched anatomic levels using standard window width and level settings. Each image was graded on a scale of 1 (worst) to 5 (best) for spatial resolution, image noise, and presence and type of artifacts. Overall image quality also was graded. Averaged scores were compared between the two scanners. In all categories, scores were slightly higher for the GE9800. However, the differences in spatial resolution, presence of artifacts, overall image quality were not significant using the sign test. There was a significant difference, in favor of the GE9800, in image noise. The types of artifacts differed; the GE9800 produced more motion artifacts from bowel and surgical clips and the Imatron C-100 produced more rib shadow artifacts projecting on the liver and spleen. While the GE9800 produced abdominal images of slightly superior quality in adults, the Imatron Ultrafast C-100 was shown to produce images suitable for routine abdominal imaging in adults.