Comparative Diagnostic and Prognostic Utility of Non-Invasive MR, 4D-Flow CMR, CT, and Transthoracic echocardiography (TTE) in Pulmonary Hypertension: A Systematic Review

Background: Accurate prognostication and risk stratification in pulmonary hypertension (PH), particularly pulmonary arterial hypertension (PAH), remain critical yet challenging. With the evolution of noninvasive imaging, modalities such as echocardiography, cardiac magnetic resonance (CMR), 4D-flow CMR, and computed tomography (CT) have shown promise in assessing right ventricular (RV) structure and function and predicting clinical outcomes.

Purpose: This systematic review aims to evaluate the diagnostic accuracy and prognostic value of advanced non-invasive imaging techniques in sensitivity, specificity, AUC, and mortality outcomes.

Methods: Following PRISMA guidelines, seven high-quality studies published between 2021 and 2025 were included. These studies employed imaging modalities across diverse international populations. QUADAS-2 was used to assess risk of bias. Outcomes of interest were sensitivity, specificity, AUC, and mortality.

Results: CMR and 4D-flow CMR showed superior diagnostic accuracy (AUC up to 0.91) and strong associations with RV end-systolic volume, VO₂, and ventilatory efficiency. CT-derived RV/LV ratios and echocardiographic strain markers emerged as independent predictors of MACE (Major Adverse Cardiovascular Events) and mortality. Consistency in follow-up timing and methodological rigor across studies strengthened the reliability of findings.

Conclusion: Advanced imaging biomarkers from echocardiography, CMR, and CT demonstrate significant prognostic utility in PH. Integration of these modalities into clinical pathways could enhance early diagnosis, risk stratification, and therapeutic monitoring. Standardization of imaging protocols remains a necessary next step for global application.