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

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%.

CITA DEL ARTÍCULO Clin Radiol. 2012 Jun 8