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Ultra-low-dose sequential computed tomography for quantitative lung aeration assessment-a translational study
Lorenzo Ball1,2,3, Anja Braune4, Francesco Corradi5
1Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Largo Rosanna Benzi 8, Genoa, Italy. lorenzo.ball@edu.unige.it.
Intensive Care Medicine Experimental
|April 6, 2017
Summary
Reduced radiation exposure in lung CT scans is possible using fewer slices and lower tube current. This method maintains quantitative analysis accuracy, offering a significant dose reduction comparable to X-rays.
Area of Science:
- Radiology
- Medical Imaging
- Pulmonary Medicine
Background:
- Quantitative computed tomography (CT) is crucial for assessing lung aeration in critically ill patients.
- Conventional CT protocols involve significant radiation exposure.
- Optimizing CT protocols for reduced radiation while maintaining diagnostic accuracy is essential.
Purpose of the Study:
- To evaluate a novel CT scanning protocol combining a reduced number of slices and lower tube current.
- To compare the quantitative analysis of lung aeration and radiation exposure with conventional CT methods.
- To assess the feasibility of extrapolating quantitative data from sparse CT slices.
Main Methods:
- Three CT protocols were tested in pigs with induced lung injury: standard spiral (180 mAs), sequential (20mm slice distance, 180 mAs), and sequential (20mm slice distance, 50 mAs).
- Retrospective analysis of spiral CT scans from critically ill patients using extracted subsets of equally spaced slices.
- Bland-Altman analysis was used to assess agreement between CT protocols.
Main Results:
- In pigs, sequential protocols showed good concordance with spiral scans, with minimal bias (≤1.9%) and agreement (≤±6.5%).
- Radiation dose was reduced by up to 97% with sequential protocols (0.09-0.21 mSv) compared to standard spiral (2.3 mSv), with minimal impact on quantitative analysis.
- In patients, quantitative lung aeration analysis from sparse slices (1mm interleaved by 20mm) showed excellent concordance (bias <1%, agreement ≤2.2%) with full spiral scans.
Conclusions:
- Combining sequential scanning with low tube current in CT significantly reduces radiation exposure without compromising quantitative lung aeration analysis.
- This optimized protocol achieves radiation doses comparable to chest X-ray, making it suitable for critically ill patients.
- Lung aeration analysis in patients can be reliably extrapolated from a subset of thin, equally spaced CT slices.