Diagnostic performance of computed tomographic angiography-based planimetry for the assessment of mitral stenosis

PURPOSE: Mitral stenosis (MS) remains diagnostically challenging, particularly in degenerative disease, where echocardiographic parameters are often unreliable. Computed tomography (CT) planimetry has been validated for other valvular diseases, but is not established for MS. This study evaluated the feasibility and diagnostic performance of CT planimetry in patients with MS compared with echocardiographic parameters. METHODS: We retrospectively analyzed 85 patients (mean age 79 ± 7.8 years, 63.5% female), who underwent ECG-gated cardiac CT within 90 days of a transthoracic echocardiography with a mean mitral transvalvular pressure gradient (MPG) ≥ 5 mmHg between 2019 and 2024. Patients with severe mitral regurgitation, mechanical valves, valve-in-valve procedures, prior edge-to-edge repair, or inadequate image quality were excluded. RESULTS: CT planimetry of mitral valve area (MVA) was feasible and showed high interobserver agreement (intraclass correlation coefficient 0.983, 95% CI 0.960;0.993). CT-derived MVA correlated inversely with MPG (rho - 0.60, 95% CI -0.73;-0.42) and moderately with echocardiographic planimetry (rho 0.58, 95% CI 0.29;0.78), particularly in degenerative and native valve subgroups. Correlations with pressure half-time (PHT)-derived MVA were weak and inconsistent (rho 0.32, 95% CI -0.01;0.60). CONCLUSION: Computed tomography planimetry showed significant correlations with MPG and echocardiographic planimetry, but not with the indirect estimation of MVA by PHT. It proved to be a feasible and highly reproducible tool for assessing MVA in MS and therefore may serve as a complementary method in cases with inconclusive or technically limited echocardiographic findings.