Low radiation and low-contrast dose pulmonary CT angiography: Comparison of 80 kVp/60 ml and 100 kVp/80 ml protocols

Clin Radiol. 2012 Sep;67(9):833-9. doi: 10.1016/j.crad.2011.11.016. Epub 2012 Jun 8.


Aim: To determine the image quality and diagnostic performance of an optimized pulmonary computed tomography angiography (CTA) protocol in terms of radiation and contrast volume saving.

Materials and methods: Seventy consecutive patients weighting ≤80 kg with clinical suspicion of pulmonary embolism (PE) were prospectively enrolled. Two pulmonary CTA protocols (group A: n = 35, 80 kV/60 ml; group B: n = 35, 100 kV/80 ml) were compared. The presence of PE, image quality parameters [contrast attenuation, contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR)] and effective radiation dose (mSv) were assessed.

Results: PE was found in 11 patients (five of group A, six of group B). The total mean attenuation of the pulmonary arteries was significantly higher in group A (362.4 ± 100.2 HU) than in group B (262.4 ± 134.3 HU), whereas the CNR and SNR did not differ statistically (14.8 ± 7.4 and 16.3 ± 7.5 for group A and 12.5 ± 8.6 and 13.8 ± 9.1 for group B, respectively). The estimated effective radiation dose was significantly lower in group A (1.1 ± 0.7 mSv) than in group B (2.7 ± 1.2 mSv).

Conclusion: In individuals weighting ≤80 kg, the evaluated pulmonary CTA protocol allows similar image quality to be achieved as compared with the conventional pulmonary CTA protocol while reducing radiation exposure by 60% and contrast media volume by 25%.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Clinical Protocols / classification*
  • Contrast Media*
  • Diagnosis, Differential
  • Female
  • Guidelines as Topic
  • Humans
  • Iohexol*
  • Male
  • Middle Aged
  • Observer Variation
  • Prospective Studies
  • Pulmonary Artery / diagnostic imaging*
  • Pulmonary Embolism / diagnostic imaging*
  • Radiation Dosage*
  • Signal-To-Noise Ratio
  • Tomography, X-Ray Computed / methods*


  • Contrast Media
  • Iohexol