Diagnostic imaging modalities in Dyspnoea and suspected acute heart failure: a systematic review with Meta-analysis.

Background: Early identification of pulmonary congestion in patients with dyspnoea is critical for managing acute heart failure. However, the optimal imaging modality remains uncertain. We compared chest radiography, lung ultrasound, computed tomography (CT), and remote dielectric sensing (ReDS) for detecting acute heart failure. Methods: We conducted a preregistered systematic review and meta-analysis of prospective observational studies in adults with dyspnoea. Medline, Embase, LILACS, and Web of Science were searched on April 9, 2025. Two reviewers independently screened studies, extracted data, and assessed bias. Sensitivity and specificity were pooled using bivariate random-effects models. Comparative performance was assessed by Bayesian network meta-analysis with weakly informative priors. Results: We included 95 studies (15,132 patients). Lung ultrasound was evaluated in 78 studies (11,790 patients), chest radiography in 30 (5966), CT in two (368), and ReDS in six (525). Some studies evaluated multiple modalities. Pooled sensitivity and specificity were 0.87 (95%CI: 0.82-0.90) and 0.89 (0.85-0.91) for lung ultrasound, 0.65 (0.58-0.72) and 0.91 (0.87-0.94) for chest radiography, 0.73 (0.53-0.87) and 0.73 (0.58-0.84) for ReDS. CT was not included in bivariate modelling because data were sparse; Bayesian network estimates were sensitivity 0.76 (95%CrI 0.62-0.86) and specificity 0.94 (0.88-0.97). CT and lung ultrasound each had >95% posterior probability of higher sensitivity than chest radiography and higher specificity than both chest radiography and ReDS. Conclusion: Lung ultrasound may serve as a first-line bedside modality. A normal chest radiograph cannot reliably exclude acute heart failure. CT showed high specificity based on limited evidence. The role of ReDS remains uncertain.