Thoracic spiral CT: influence of subsecond gantry rotation on image quality.


Journal Article

PURPOSE: To determine if the lower milliampere second setting and shorter acquisition time of subsecond spiral computed tomography (CT) affects the image quality of thoracic CT scans. MATERIALS AND METHODS: In 92 consecutive outpatients referred for thoracic CT, spiral CT (120 kV, 292 mA) was performed with 1-second (n = 45) or 0.75-second (n = 47) scanning time. An equal percentage of patients (70%) in each group received intravenous contrast medium. At six mediastinal and six lung zones, degradation due to motion and noise, respectively, were graded independently on a four-point scale by three blinded radiologists. Statistically significant differences were determine with a two-tailed test. RESULTS: Mediastinal image quality was significantly better on 0.75-second scans than on 1-seconds scans (P < .001). Regions with the greatest improvement in image quality were around the aortic root, cardiac ventricles, and aortic arch. Lung image quality was also better on 0.75-second scans than on 1-second scans (P = .04). On 0.75- and 1-second scans, respectively, motion-related artifacts were found to degrade image quality 6.2 and 8.7 times more than noise-related artifacts in the mediastinum and 2.6 and 3.9 times more in the lungs. CONCLUSION: Subsecond spiral CT is associated with improved clarity and diminished motion artifacts on mediastinal and pulmonary images when compared with 1-second spiral CT.

Full Text

Duke Authors

Cited Authors

  • Rubin, GD; Leung, AN; Robertson, VJ; Stark, P

Published Date

  • September 1998

Published In

Volume / Issue

  • 208 / 3

Start / End Page

  • 771 - 776

PubMed ID

  • 9722858

Pubmed Central ID

  • 9722858

International Standard Serial Number (ISSN)

  • 0033-8419

Digital Object Identifier (DOI)

  • 10.1148/radiology.208.3.9722858


  • eng

Conference Location

  • United States