Quantifying Mitral Regurgitation
Mitral regurgitation (MR) or mitral insufficiency (MI) is quantified easily by cardiac magnetic resonance imaging. MR appears as one or more flow jets originating from the mitral valve and projecting into the left ventricle. Typically, the jets are holosystolic, easily discernible on a 3-chamber, long-axis view, and are best visualized on imaging sequences with longer echo times (TE) (Fig.).
To quantify regurgitant volume when isolated regurgitation (i.e., when no other regurgitant lesions or intracardiac shunts are present) is evident, the following calculations may be employed:
- The difference between left ventricular stroke volume (LVSV, ml) and forward flow (Qs or Qp, ml); and/or
- The difference between LVSV (ml) and right ventricular stroke volume (RVSV, ml).
MR severity may be determined as categorized below (Tb.).
|Tb. Regurgitation Severity|
|Degree of regurgitant||Regurgitant volume (ml)||Regurgitant fraction (%)|
|Regurgitant volumes are measured directly (ml). Regurgitant fraction (%)= volume of MR (ml)/LVSV (ml)|