Improving cardiac computed tomography angiography image quality and diagnostic confidence for atrial fibrillation after left atrial appendage closure using a second-generation whole-heart motion correction algorithm.

Background: Left atrial appendage (LAA) closure is a key stroke prevention strategy for non-valvular atrial fibrillation (AF). Cardiac computed tomography angiography (CTA) has emerged as an effective non-invasive alternative to transesophageal echocardiography for follow-up assessment. However, image quality and diagnostic confidence are often compromised by device-related artifacts and cardiac motion, highlighting the need for advanced motion correction techniques such as Snapshot Freeze 2 (SSF2), a second-generation whole-heart algorithm. The effects of SSF2 on patients with LAA closure have not yet been examined. Thus, this study sought to examine the ability of SSF2 to improve cardiac CTA image quality and diagnostic confidence for AF after LAA closure. Methods: This retrospective study included 42 LAA closure patients who underwent single-heartbeat cardiac CTA on a 16-cm detector computed tomography scanner. The images were reconstructed using the standard reconstruction method (SRM), the first-generation Snapshot Freeze 1 (SSF1), and SSF2. Two experienced radiologists assessed the image artifacts caused by the LAA (at the proximal, central, and distal regions), boundaries, visualization clarity, and diagnostic confidence for LAA closures using a five-point scale. Regions of interest (ROIs) were placed in three areas of LAA closures with heavy artifacts to measure the standard deviation (SD). The Friedman test with a post-hoc analysis was used to compare the quantitative and qualitative results. All the continuous variables are presented as mean ± SD or median (interquartile range), while the subjective image scores are expressed as median (interquartile range) unless otherwise specified. Results: In relation to the quantitative assessment, SSF2 had the smallest SD values, while the SRM had the largest SD values. SSF2 had significantly lower (better) artifact scores for the proximal, central, and distal regions of the LAA [1 (0-1), 1 (0-1), 1 (0-1), respectively] than the SRM [2 (1-2), 2 (1-3), 1 (0-3)] and SSF1 [1 (1-2), 2 (1-3), 1 (0-2)], as well as better scores for the LAA closure boundaries [4 (4-5)] and LAA visualization [4 (4-5)] than the SRM [3 (2-4) and 3 (3-4)] and SSF1 [4 (3-4) and 4 (3-4)], respectively. Excellent diagnostic confidence (i.e., scores of four or greater) was achieved in 30.9%, 52.4%, and 90.5% of the cases using the SRM, SSF1, and SSF2, respectively. Conclusions: SSF2 significantly reduces the artifacts caused by LAA closure, and improves image quality, visualization, and diagnostic confidence in cardiac CTA of patients with LAA closure, compared with the SRM and SSF1. This could improve both the detection of device-related complications and patient management.