In imaging, which prolapse pattern is most commonly associated with a centrally directed MR jet?

• A. Anterior leaflet prolapse
• B. Posterior leaflet prolapse
• C. Normal valve without prolapse
• D. Both leaflets prolapse

Answer: (D)

Jet direction on color Doppler reflects where the regurgitant orifice sits. When both mitral leaflets prolapse, the coaptation failure is central, creating a regurgitant opening that’s located near the middle of the valve. This central orifice produces a jet that projects toward the center of the left atrium rather than toward a specific wall. If only one leaflet prolapses, the orifice is off to one side, resulting in an eccentric jet directed toward the opposite atrial wall (anterior leaflet → jet toward posterior wall; posterior leaflet → jet toward anterior wall). Thus, a centrally directed MR jet most commonly occurs with bileaflet prolapse.