Mitral Stenosis in the Multimodality Imaging Era: Pitfalls, Stress Echocardiography, and Integrated Therapeutic Assessment

Background/Objectives: Mitral stenosis (MS) remains a clinically relevant condition worldwide, with rheumatic and degenerative aetiologies contributing to a broad spectrum of disease. Accurate assessment of MS severity is essential for clinical decision-making but is often challenged by technical limitations, complex hemodynamic interactions, and the heterogeneous anatomical characteristics of different MS aetiologies. This review aims to provide a comprehensive overview of the contemporary multimodality imaging assessment of MS, with particular emphasis on the pitfalls of conventional transthoracic echocardiography (TTE), the incremental value of advanced imaging modalities, and their integration into diagnostic and therapeutic decision-making. Methods: A targeted narrative review of the literature was conducted focusing on multimodality imaging approaches and their integration into clinical practice. Particular emphasis was placed on TTE parameters, three-dimensional (3D) TTE, stress echocardiography, transoesophageal echocardiography (TOE), cardiac computed tomography (cCT), and cardiac magnetic resonance (CMR), highlighting their complementary roles in anatomical characterization, hemodynamic assessment, procedural planning, and clinical decision-making. Results: Conventional 2D TTE remains the cornerstone for MS evaluation; however, widely used parameters such as mean transmitral gradient (TMG) and pressure half-time (PHT) are highly load-dependent and may lead to misclassification of disease severity in the presence of altered hemodynamic conditions (e.g., tachycardia, atrial fibrillation (AF), or reduced cardiac output). Although direct planimetry remains the anatomical reference standard, its accuracy may be limited by operator dependency, calcification, and complex valve geometry. In this context, three-dimensional TTE (3D TTE) provides incremental value by enabling more accurate visualization of the mitral valve (MV) orifice and improving measurement reproducibility. Stress TTE plays a key role in patients with discordant symptoms or borderline resting findings by unmasking clinically significant disease during exercise. In selected patients, TOE, cCT, and CMR provide complementary information for the evaluation of complex valve morphology, mitral annular calcification (MAC), ventricular remodelling, and procedural planning, particularly in degenerative mitral stenosis (DMS) and candidates for transcatheter interventions. Conclusions: The evaluation of MS requires an integrated, multiparametric, multimodality imaging approach. Combining conventional TTE with stress imaging and complementary advanced modalities improves diagnostic accuracy, facilitates patient selection for intervention, and supports individualized clinical decision-making, particularly in patients with complex anatomy or discordant imaging findings.