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Advanced scanners lowered radiation exposure during CT angiography
Use of advanced dual-source CT scanners was associated with significantly reduced radiation exposure among patients evaluated for CAD, pulmonary embolism and other CV conditions, without a negative impact on image quality, researchers reported in the Journal of Cardiovascular CT.
The prospective, multicenter, controlled study utilized scan data collected from patients who underwent CT angiography using 64-slice scanners (control group, n=1,097) and CT angiography using 128-slice dual-source scanners with prospectively triggered and high-pitch spiral scan modes (study group, n=988). The patients were from nine centers and the data analyzed were gathered from April 2011 to March 2012. The cohort included 1,051 patients evaluated for CAD (509 in the control group; 542 in the study group), 528 for pulmonary embolism (267 in the control group; 261 in the study group), 419 for aortic disease (268 in the control group; 151 in the study group) and 87 to rule all three conditions (53 in the control group; 34 in the study group).
The primary endpoint was total radiation dose. Other evaluated factors included quantitative and semi-quantitative measures of image quality. The researchers noted that no “best practice” guidelines were provided and no recommendations were given to improve image quality or reduce radiation dose, in order to assess results in real-world practice.
Use of advanced scanners was associated with significantly lower median dose-length product compared with the control group (260 mGy/cm vs. 669 mGy/cm; P<.0001). This dose reduction was observed regardless of whether patients were evaluated for CAD, pulmonary embolism, aortic disease or triple rule-out (P<.001 for all). Median volume CT dose index was also significantly lower in the advanced scanner group compared with the control group (9.1 mGy vs. 24 mGy; P<.001).
Image quality was not significantly different with use of the different scanners.
Within the advanced scanner group, 472 patients were evaluated using the high-pitch mode. Researchers observed a significant difference in median dose between those evaluated via high-pitch mode vs. those who were not (2.4 mSv vs. 5.1 mSv; P<.001).
Factors associated with achieving the target dose-length product of <360 mGy/cm and effective dose <5 mSv on multivariable step-down logistic regression analysis included use of a scanner capable of high-pitch mode (OR=16.4; 95% CI, 11.64-23.11), BMI <30 kg/m2 (OR=1.62; 95% CI, 1.13-2.31) and tube potential of 100 kV or lower (OR=4.21; 95% CI, 2.92-6.08).
“This multicenter, ‘real-world’ study demonstrates that use of advanced, second-generation dual-source CT scanners with high-pitch scanning capability results in significant radiation dose reduction in patients undergoing routine thoracic CT angiography, without compromising diagnostic image quality,” the researchers concluded. “… This study has important implications for radiation safety in real-world clinical practice of cardiovascular CT.”
Disclosure: The researchers report no relevant financial disclosures.