Computed tomography angiography of the carotid arteries at low kV settings: a prospective randomised trial assessing radiation dose and diagnostic confidence

Eur Radiol. 2011 Nov;21(11):2434-44. doi: 10.1007/s00330-011-2188-1. Epub 2011 Jun 28.


Objective: To assess radiation dose and diagnostic image quality of a low-dose (80 kV) versus a standard-dose (120 kV) protocol for computed tomography angiography (CTA) of the supra-aortic arteries.

Methods: 64-slice CTA of the supra-aortic arteries was performed in 42 consecutive patients using randomly either 80 or 120 kV at 300 absolute mAs. Intravascular attenuation values, contrast-to-noise (CNR) and signal-to-noise ratio (SNR) measurements were performed at three levels. Two readers assessed image quality by using a four-point scale. The effective dose (ED) was calculated to assess the differences in radiation exposure.

Results: Intravascular attenuation values at 80 kV were higher in the common carotid artery, the carotid bifurcation and the internal carotid artery (p < 0.001). CNR and SNR differed at the internal carotid artery, with higher values in the 80-kV group (p > 0.05). Both readers revealed a significantly better image quality at 120 kV only at the common carotid artery (p < 0.001; p = 0.007). Mean ED was significantly lower at 80-kV (1.23 ± 0.09 vs. 3.99 ± 0.33 mSv; p < 0.001).

Conclusion: Tube voltage reduction to 80 kV in CTA of the supra-aortic arteries allows for significant radiation dose reduction but has limitations at the level of the common carotid artery.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Algorithms
  • Angiography / methods*
  • Aorta / pathology*
  • Carotid Arteries / pathology*
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Middle Aged
  • Prospective Studies
  • Radiometry / methods*
  • Tomography, X-Ray Computed / methods*