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 CIA protocol while reducing radiation exposure by 60% and contrast media volume by 25%. (C) 2012 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.