Low dose dual-source CT angiography of the thoracic aorta

Cormac Farrelly*, Amir Davarpanah, Aoife N. Keeling, John Sheehan, Ann Ragin, Vahid Yaghmai, James C. Carr

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


The purpose of this study was to investigate the effects of a prospective ECG-gated, low kilovoltage and low mAs protocol on image quality and radiation dose when acquiring CT angiography of the thoracic aorta (CTTA). Sixty patients with a body mass index (BMI) of less than 30 and a heart rate of less than 100 beats per minute (bpm) were included in the study. Thirty consecutive patients were examined with retrospective ECG-gating and standard parameters (group A) (120 kVp, 340 reference effective mAs).The next thirty (group B) were examined with prospective ECG-gating, 100 kVp and 170 mAs. Quantitative analysis included measurements of image resolution of the thoracic aorta at three levels, mean attenuation in the aorta and signal to noise ratio (SNR). Qualitative analysis assessed image artifact and graded image quality on five point scales. Effective radiation doses were estimated. The radiation dose of group A was 26.2 ± 6.0 mSv (mean ± standard deviation). For group B it was 2.9 ± 0.5 mSv (P < 0.001). Mean aortic attenuation was significantly higher in group B than group A (487 ± 100 Hu and 372 ± 74 Hu) (P < 0.01).SNR was significantly higher in group A (21.7 ± 5.7 compared to 14.5 ± 5.3) (P < 0.01). Image resolution was significantly higher in group B at all measured anatomical levels (P < 0.01). There was no significant difference in the final subjective scores between group A and group B (Mann-Whitney U = 438, P = 0.79). High quality low dose CTTA is clinically achievable, in patients with a BMI less than 30 and a heart rate less than 100 bpm, using a prospective ECG-gated, low kilovoltage, low mAs technique.

Original languageEnglish (US)
Pages (from-to)1025-1034
Number of pages10
JournalInternational Journal of Cardiovascular Imaging
Issue number7
StatePublished - Oct 2011


  • CT angiography
  • Computed
  • Dual source CT
  • Low dose
  • Prospective gating
  • Thoracic aorta
  • Tomography

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Radiology Nuclear Medicine and imaging


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