A fast and reproducible method to estimate left atrial volume using cardiac computed tomography

Purpose: The purpose of this study was to do better than the simple maximal axial area (MAreaax) and to validate simple, fast and robust orthogonal methods for determining the left atrium volume (LAV) with cardiac CT (CCT). Material and methods: A total of 60 patients who underwent CTT were retrospectively included. There were 30 men and 30 women with a mean age of 59 +/- 12 (SD) years (range: 27-80 years), using four methods to assess LAV beyond the MAreaax: two orthogonal methods requiring the measurements of axial, coronal and sagittal planes of 3 diameters LAV(3diam) or 3 area LAV(3Areas); Area-length biplane method LAV(biplane); and volumetric method LAV(volumetric) using a semi-automated tool that served as the reference standard. The orthogonal methods were applied on contrast-enhanced (IV+) and unenhanced (IV-) CCT images. Comparisons were performed using Pearson correlation test (r) and Bland-Altman analysis. Inter and intra-observer variability were assessed using intraclass correlation coefficient (ICC) with a two-way mixed-effects model. Results: On IV+ CCT, LAV(biplane), LAV3diam-(IV)+, LAV(3Areas-IV)+ underestimated LAV (-15 +/- 1.99 mL; 21 +/- 1.37 mL;-15 +/- 1.98 mL; all P < 0.001). LAV(3diam-IV+), LAV(3Areas-IV+) better correlated with reference standard (r = 0.97 and 0.98) than LAVbiplane (r = 0.79) as well as MAreaax (r = 0.90). Estimating LAV on IV further showed high correlation against the reference (r = 0.93 and 0.95 for LAV(3diam-IV-) and LAV(3Areass-IV-), respectively). Intra-and inter-observer ICC increased from LAV(volumetric) (2.43% and 3.09%); LAV(3Areas-IV+) (3.04 and 3.30%); LAV(3Areas-IV-) (3.34 and 4.23%), LAV(3diam-IV+) (3.36 and 5.11%); LAV(3diam-IV-)(5.16 and 6.90%); to LAV(biplane) (9.65 and 10.28%). Conclusions: Better than MArea(ax), orthogonal methods using either diameter or surface are fast and reproducible methods to assess LAV on CCT when performed with or without intravenous administration of contrast material. (C) 2021 Societe francaise de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Automated summary

This study aimed to validate the advantages of using orthogonal methods to measure left atrium volume and compare them with the simple maximal axial area. The results showed that the orthogonal methods, especially 3 diameters LAV and 3 areas LAV, had better correlation with the reference standard and higher reproducibility.