Open Access

ARTICLE

Cardiothoracic Ratio for Assessment of Ventricular Volumes and Function in Patients with Repaired Tetralogy of Fallot

Jacob PL Ho¹, Carol WK Ng², Wilfred HS Wong³, Yiu-fai Cheung^1,3,*

1 Department of Paediatrics and Adolescent Medicine, Hong Kong Children’s Hospital, Hong Kong SAR, China
2 Department of Radiology, Hong Kong Children’s Hospital, Hong Kong SAR, China
3 Department of Paediatrics and Adolescent Medicine, School of Clinical Medicine, The University of Hong Kong, Hong Kong SAR, China

* Corresponding Author: Yiu-fai Cheung. Email:

Congenital Heart Disease 2025, 20(2), 201-211. https://doi.org/10.32604/chd.2025.063217

Received 08 January 2025; Accepted 13 March 2025; Issue published 30 April 2025

Abstract

Background: The role of cardiothoracic ratio (CTR) from the chest radiograph for assessment of ventricular enlargement and function in repaired tetralogy of Fallot (TOF) is conflicting. This study aimed to determine the associations between CTR and cardiac magnetic resonance (CMR)-derived ventricular volumes and indices of ventricular function in adolescents and young adults with repaired TOF. Methods: The CTR and CMR findings, performed within 12 months of each other, were reviewed in 76 patients aged 22.1 ± 6.4 years. Associations between CTR and CMR parameters including right (RV) and left ventricular (LV) volumes and ejection fraction were determined. Diagnostic accuracies of CTR in identifying moderate to severe RV or LV dilation were assessed by calculation of area under the receiver operator characteristic curves (AUC). Results: Patients with normal CTR and those with increased CTR > 0.5 had similar right and left ventricular volumes, ejection fraction, and pulmonary regurgitant fraction (all p > 0.05). There were no significant correlations between CTR and RV end-diastolic (r = 0.06, p = 0.65) and end-systolic (r = 0.06, p = 0.65) volumes, LV end-diastolic (r = 0.23, p = 0.08) and end-systolic (r = 0.18, p = 0.16) volumes, and LV (r = −0.07, p = 0.60) and RV (r < −0.01, p = 0.97) ejection fraction. The CTR failed to distinguish between patients with moderate to severe RV (AUC 0.50) or LV (AUC 0.46) dilation from patients without ventricular dilation. Conclusions: The CTR based on the chest radiograph failed to reflect dilation or reduced ejection fraction of either the right or the left ventricle in adolescents and young adults with repaired TOF.

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