Thoracic spiral CT: Influence of subsecond gantry rotation on image quality

Geoffrey D. Rubin, Ann N. Leung, Valerie J. Robertson, Paul Stark

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


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 determined with a two-tailed t test. RESULTS: Mediastinal image quality was significantly better on 0.75-second scans than on 1-second 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.

Original languageEnglish (US)
Pages (from-to)771-776
Number of pages6
Issue number3
StatePublished - Sep 1998
Externally publishedYes


  • Computed tomography (CT), artifact
  • Computed tomography (CT), technology
  • Lung, CT
  • Mediastinum, CT

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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