Effect of the Second-generation Motion Correction Algorithm on Coronary Artery Calcium Scoring

The second-generation motion correction algorithm, Snapshot Freeze 2.0 (SSF2), is designed to suppress coronary artery motion in cardiac CT angiography. This study aimed to evaluate whether SSF2 improves unenhanced CT images and to compare the coronary artery calcium score (CACS) values reconstructed with and without SSF2.

One hundred nineteen patients with coronary artery calcium (CACS >0) were enrolled in this study. Unenhanced CT for CACS was performed with a phase window limited to 75% of the R-R interval, using 120 kVp and automatic tube current modulation. CACS values were measured on images with and without SSF2, and absolute differences were calculated. Two radiologists assessed the overall image quality, focusing on coronary artery motion, using a 4-point scale (1=uninterpretable, 4=no motion artifacts).

The absolute differences in CACS for patients with heart rates of 60-95 bpm (n=85) were larger than those with heart rates of up to 59 bpm (n=21) or above 95 bpm (n=13) (median: 10.6, range: 0.1 to 171.2; median: 9.3, range: 0.8 to 31.8; median: 6.0, range: 1.6 to 43.4, respectively). In patients with heart rates of 60 to 95 bpm, SSF2 improved image quality scores ( P <0.001); however, for heart rates of up to 59 bpm or above 95 bpm, the improvements were not significant ( P =0.18 and 0.10, respectively).

SSF2 reduces motion artifacts in the coronary arteries on unenhanced CT and significantly alters the CACS values. A more accurate calcification assessment is anticipated with SSF2, especially in patients with heart rates of 60 to 95 bpm.