New motion-correction algorithm improves CCTA image quality

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Standard (a) and motion-corrected (b) coronary computed tomography angiography reconstructions of a male patient with a heart rate of 78 beats/min. Motion correction improves image quality in three-dimensional reconstruction (left panel), multiplanar reconstruction (middle panel), and transaxial slices (right panel) in the right coronary artery, which was mainly affected by motion artifact (arrows).
Source: (Academic Radiology 2014;21:312-317)

A novel, vendor-specific, motion-corrected reconstruction algorithm has been shown to improve image quality and interpretability of prospectively electrocardiogram (ECG)-triggered low-dose coronary CT angiography (CCTA) regardless of insufficient heart rate control, according to a study published in the March issue of Academic Radiology.

Though CCTA noninvasively evaluates coronary artery disease (CAD) with high accuracy, motion artifacts are a major limitation of the tool. This is a particular issue when prospective ECG-triggering protocols are used to reduce radiation dose because of insufficient heart rate control.

“Recently, a novel, vendor-specific, motion-correction algorithm has been shown to improve image quality, interpretability, and diagnostic accuracy in patients undergoing CCTA without heart rate control by integrating vessel path and velocity from multiple adjacent cardiac phases to restore the vessel lumen,” wrote the study’s lead author, Tobias A. Fuchs, MD, of the University Hospital Zurich in Switzerland, and colleagues. “However, because of the use of retrospective gating, mean radiation dose was more than 13 mSv, which is substantially higher than with prospective ECG triggering with values averaging 2 mSv in daily clinical use.”

The researchers assessed the impact of the algorithm on coronary image quality and interpretability while using the lowest possible padding for prospectively ECG-triggered low-dose CCTA. This was then compared to conventional reconstructions in patients with insufficient heart rate control despite β-blockade. The study’s population included 40 patients overall. Two blinded observers assessed the image quality using a four point Likert scale and the fraction of interpretable segments with motion correction versus standard reconstruction.

The image reconstruction with motion correction increased median coronary artery image quality score in comparison to standard reconstruction. Motion-corrected reconstruction significantly improved the overall interpretability of coronary arteries with a ten percent increase. The application of motion correction reclassified uninterpretable to interpretable images in six patients. The estimated mean effective radiation dose was 2.3 mSv.

“Our results are the first to document the impact of a novel motion-correction method on image quality of low-dose CCTA with prospective ECG triggering,” wrote Fuchs and colleagues. “In patients undergoing CCTA, despite insufficient heart rate control, the combination of data acquisition with enlarged padding and a new reconstruction algorithm yielded a significant improvement in image quality and interpretability.”