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Pulmonary valve

The pulmonary valve is a semilunar cardiac valve located at the junction of the right ventricle and pulmonary trunk. It consists of three cusps—the anterior, right, and left cusps—without chordae tendineae or papillary muscles. The valve opens during systole to allow ejection of blood into the pulmonary trunk and closes during diastole to prevent regurgitation into the right ventricle. Its anatomy and function are crucial in congenital heart disease, pulmonary hypertension, and pre- or post-surgical imaging evaluation.

Synonyms

  • Pulmonic valve

  • Right semilunar valve

  • Valve of pulmonary trunk

Function

  • Opens during right ventricular systole for blood ejection into pulmonary circulation

  • Closes during diastole to prevent backflow into the right ventricle

  • Ensures unidirectional blood flow

  • Contributes to right ventricular outflow dynamics and pressure regulation

MRI Appearance

T1-weighted images:

  • Valve cusps appear as thin, hypointense structures in the right ventricular outflow tract

  • Blood flow produces a signal void (black lumen)

  • Limited role in dynamic evaluation

T2-weighted images:

  • Cusps remain low signal intensity compared to surrounding myocardium

  • Abnormal turbulent flow (e.g., stenosis or regurgitation) may appear as signal voids within the lumen

Cine MRI (T2-weighted / SSFP sequences):

  • Provides real-time dynamic imaging of valve motion

  • Clearly demonstrates systolic opening and diastolic closure

  • Useful for detecting stenosis, regurgitation, leaflet thickening, or restricted motion

  • Quantifies flow velocity, regurgitant fraction, and stroke volume with phase-contrast sequences

T1 Post-Contrast (Gadolinium-enhanced):

  • Enhances visualization of the valve annulus and adjacent great vessels

  • Cusps typically show minimal enhancement

  • Abnormal enhancement may suggest fibrosis, pannus formation, or infective endocarditis

CT Appearance

Non-contrast CT:

  • Pulmonary valve cusps are thin and poorly visualized

  • Calcifications (rare compared to the aortic valve) may be detected

Contrast-enhanced CT (CT Angiography):

  • Excellent for evaluating the valve annulus, cusps, and right ventricular outflow tract

  • Detects congenital anomalies (e.g., bicuspid valve), stenosis, regurgitation, prosthetic valve integrity

  • Multiplanar reconstructions allow precise preoperative planning and post-procedure assessment

MRI images

Pulmonary Valve anatomy MRI image

CT image

Pulmonary valve anatomy MRI axial image -img-00000-00000