The International Journal of Cardiovascular Imaging

, Volume 27, Issue 7, pp 1025–1034 | Cite as

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
Original Paper

Abstract

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.

Keywords

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

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Copyright information

© Springer Science+Business Media, B.V. 2010

Authors and Affiliations

  • Cormac Farrelly
    • 1
  • Amir Davarpanah
    • 1
  • Aoife N. Keeling
    • 1
  • John Sheehan
    • 1
  • Ann Ragin
    • 1
  • Vahid Yaghmai
    • 1
  • James C. Carr
    • 1
  1. 1.Department of Radiology, Cardiovascular Imaging SectionNorthwestern UniversityChicagoUSA

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