title: Image quality, contrast enhancement, and radiation dose of ECG-triggered high-pitch CT versus non-ECG-triggered standard-pitch CT of the thoracoabdominal aorta.
abstract: OBJECTIVE
  We sought to compare image quality, contrast enhancement, and radiation dose in patients undergoing ECG-triggered high-pitch helical CT or non-ECG-synchronized helical CT of the thoracoabdominal aorta.
  
  
  METHODS
  We retrospectively assessed data from 101 consecutive patients (81 men, 20 women; mean age, 71 ± 11 [SD] years) undergoing clinically indicated CT angiography (CTA) of the thoracoabdominal aorta on a dual-source scanner using either the ECG-triggered high-pitch helical mode (group 1, n = 52) or non-ECG-synchronized standard-pitch helical mode (group 2, n = 49) during the arterial phase. Two independent readers assessed image quality, noise, and contrast enhancement throughout the thoracoabdominal aorta. Scanner-reported dose-length product values were used to estimate effective dose values.
  
  
  RESULTS
  Image quality at the root-proximal ascending level was higher in group 1 (mean ± SD, 2.81 ± 0.40) than in group 2 (1.22 ± 0.47; p < 0.0001), with similar quality for both groups noted at other levels. Group 1 scans displayed higher image noise at all levels. The groups received a similar volume of contrast material (p = 0.77), and similar percentages of cases with acceptable contrast enhancement (> 250 HU) were noted in the two groups. The estimated radiation burden was significantly lower in group 1 (mean ± SD, 5.4 ± 1.8 mSv) than in group 2 (14.4 ± 5.1 mSv; p < 0.0001).
  
  
  CONCLUSIONS
  Imaging of the thoracoabdominal aorta with ECG-triggered high-pitch CTA provides higher quality images of the aortic root and ascending aorta with sufficient contrast enhancement and decreased estimated radiation dose compared with non-ECG-synchronized standard-pitch helical CT.
authors.affiliation: Imaging Institute, Cardiovascular Section, Cleveland Clinic, OH 44195, USA. bolenm@ccf.org
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bolen
authors.forename: Zoran B
authors.initials: ZB
authors.lastname: Popovic
authors.forename: Navdeep
authors.initials: N
authors.lastname: Tandon
authors.forename: Scott D
authors.initials: SD
authors.lastname: Flamm
authors.forename: Paul
authors.initials: P
authors.lastname: Schoenhagen
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Halliburton
mesh_terms: D000368:Aged; D000792:Angiography / Q000379:methods*; D001018:Aortic Diseases / Q000000981:diagnostic imaging*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D003287:Contrast Media; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D011829:Radiation Dosage; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide