To assess the feasibility and reliability of the use of artificial intelligence post-processing to calculate the RV:LV diameter ratio on computed tomography pulmonary angiography (CTPA) and to investigate its prognostic value in patients with acute PE.
Single-centre, retrospective study of 101 consecutive patients with CTPA-proven acute PE. RV and LV volumes were segmented on 1-mm contrast-enhanced axial slices and maximal ventricular diameters were derived for RV:LV ratio using automated post-processing software (IMBIO LLC, USA) and compared to manual analysis in two observers, via intraclass coefficient correlation analysis. Each CTPA report was analysed for mention of the RV:LV ratio and compared to the automated RV:LV ratio. Thirty-day all-cause mortality post-CTPA was recorded.
Automated RV:LV analysis was feasible in 87% (n = 88). RV:LV ratios ranged from 0.67 to 2.43, with 64% (n = 65) > 1.0. There was very strong agreement between manual and automated RV:LV ratios (ICC = 0.83, 0.77–0.88). The use of automated analysis led to a change in risk stratification in 45% of patients (n = 40). The AUC of the automated measurement for the prediction of all-cause 30-day mortality was 0.77 (95% CI: 0.62–0.99).
The RV:LV ratio on CTPA can be reliably measured automatically in the majority of real-world cases of acute PE, with perfect reproducibility. The routine use of this automated analysis in clinical practice would add important prognostic information in patients with acute PE.
• Automated calculation of the right ventricle to left ventricle ratio was feasible in the majority of patients and demonstrated perfect intraobserver variability.
• Automated analysis would have added important prognostic information and altered risk stratification in the majority of patients.
• The optimal cut-off value for the automated right ventricle to left ventricle ratio was 1.18, with a sensitivity of 100% and specificity of 54% for the prediction of 30-day mortality.
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Computed tomography pulmonary angiography
Intraclass coefficient correlation
Right ventricle to left ventricle
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The scientific guarantor of this publication is Jonathan CL Rodrigues.
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Bland-Altman plots showing agreement analysis for intra-observer measurements for rater 1, rater 2 and automated software and for inter-observer measurements between rater 1 / rater 2, automated software / rater 1 and automated software / rater 2. (PDF 344 kb)
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Foley, R.W., Glenn-Cox, S., Rossdale, J. et al. Automated calculation of the right ventricle to left ventricle ratio on CT for the risk stratification of patients with acute pulmonary embolism. Eur Radiol (2021). https://doi.org/10.1007/s00330-020-07605-y
- Artificial intelligence
- Pulmonary embolism
- Computed tomography pulmonary angiography
- Right ventricle to left ventricle ratio