Effect of Snapshot Freeze on Cardiac CT Image Quality

Aims:

To investigate the motion correction algorithm Snapshot-Freeze(SSF) compared to standard reconstruction(STD) in patients randomized to receive beta-blockers(BB) or no beta-blockers(non-BB) before coronary CT angiography (CCTA), and to investigate if SSF can replace BB.

Methods:

The study included 140 consecutively recruited patients scheduled to CCTA to rule out coronary artery disease.

The inclusion criteria were: age ≥ 18 years, Glomerular filtration rate ≥ 60 mL/min, Heart Rate between 60 and 85 bpm before the scan. The exclusion criteria were: irregular heart rhythm or history of allergic reaction to contrast agents. Patients were randomized to the BB group or the non-BB group. The trial complied with the Declaration of Helsinki and was approved by the local ethics committee. Written informed consent was obtained from all patients.

Image quality score:

The evaluation was performed according to the Likert score as follows: 1: excellent, no motion artifacts, clear delineation of the segments; 2: good, minor artifacts, mild blurring of the segment; 3: adequate, moderate artifacts, moderate blurring without structure discontinuity; and 4: poor and non-diagnostic, with doubling or discontinuity in the course of the segments, preventing evaluation or producing vessel structures that were not differentiable. In cases where the image quality was less than excellent (Likert score 2-4), the readers noted the reason(s) for the observed artifact.

Statistical analyses:

Quantitative variables were expressed as mean ± standard deviation, and categorical values as frequencies or percentages. Values from the Likert score were dichotomized to excellent vs. non-excellent (Likert score 1 vs. 2-4), and diagnostic vs. non-diagnostic (Likert score 1-3 vs. 4). McNemar's test was performed to test categorical variables separately per-vessel and per-patient level. Analyses for all segments were calculated by the Wilcoxon signed-rank test.