Quantifying Tricuspid Regurgitation
Tricuspid regurgitation (TR) or tricuspid insufficiency (TI) may be quantified by cardiac magnetic resonance imaging. TR appears as one or more flow jets emanating from the tricuspid valve and projecting into the right ventricle. The jets often are holosystolic and readily apparent on the 4-chamber, long-axis view. They are best visualized on imaging sequences with longer echo times (Fig.). 
To quantify regurgitant volume when isolated regurgitation (i.e., when no other regurgitant lesions or intracardiac shunts are present) is extant, the following calculations may be employed:
- The difference between right ventricular stroke volume (RVSV, ml) and forward flow (Qs or Qp, ml); and/or
- The difference between RVSV and left ventricular stroke volume (LVSV, ml).
TR severity may be determined as categorized below (Tb.).
| Tb. Regurgitation Severity | ||
| Degree of regurgitation | Regurgitant volume (ml) | Regurgitant fraction (%) |
| Mild | <30 | <30 |
| Moderate | 30-59 | 30-50 |
| Severe | ≥60 | >50 |
| Regurgitant volumes are measured directly. Regurgitant fraction (%)= volume of TR (ml)/RVSV (ml) | ||
