Impact of left atrial enlargement on image quality in coronary computed tomography angiography

Abstract

PurposeTo assess the associations between simple measurements of left atrial (LA) size and image quality of coronary computed tomography angiography (CCTA). Materials and methodsFour hundred and nineteen patients who underwent CCTA were retrospectively examined. Image quality was measured by coronary artery attenuation and contrast-to-noise ratio (CNR) of the proximal coronary artery (mean values of right coronary artery and left main trunk). LA transverse (LA-TRA) and anterior-posterior (LA-AP) diameter were measured on non-contrast CT images of the chest. The relationships of coronary attenuation and CNR with LA diameters were assessed by Pearson's correlation or Spearman's rank correlation coefficient and multivariate linear regression analysis. Receiver operating characteristic curves were used to assess the predictive value of LA diameters for image quality. ResultsBoth coronary artery attenuation value and CNR were independently correlated with LA-AP diameter (r = −0.38, for artery attenuation; r = −0.16, for CNR, both p < 0.001), and LA-TRA diameter (r = −0.2, p < 0.001, for artery attenuation; r = −0.11, p = 0.02, for CNR), respectively. With a cutoff value of 34 mm, the LA-AP diameter had a sensitivity of 85.2%, a specificity of 68.4% and an area under curve (AUC) of 0.77 for prediction of insufficient image quality (coronary artery attenuation less than 326 Hounsfield units). ConclusionCoronary artery attenuation and CNR in CCTA decreased with larger LA size.