Topics

Topic

design image
Valve of coronary sinus

The valve of the coronary sinus, also known as the Thebesian valve, is a semicircular fold of endocardium located at the orifice of the coronary sinus where it opens into the right atrium, between the inferior vena cava and the tricuspid valve.

The valve is highly variable in size, shape, and prominence. In most individuals, it appears as a small crescent-shaped flap that partially covers the coronary sinus opening, preventing regurgitation of blood into the coronary sinus during atrial contraction. In some cases, it may be large and fenestrated, and in rare cases it can completely cover the coronary sinus ostium, which may complicate procedures such as cardiac resynchronization therapy (CRT) lead placement or retrograde cardioplegia delivery.

Synonyms

  • Thebesian valve

  • Coronary sinus valve

  • Valve of coronary sinus ostium

Function

  • Prevents regurgitation of right atrial blood into the coronary sinus during atrial systole

  • Maintains unidirectional venous return from the cardiac veins into the right atrium

  • Serves as an anatomical landmark during right atrial procedures and imaging

  • Can influence catheter access to the coronary sinus in interventional cardiology

T1-weighted images:

  • Appears as a thin, low-signal flap at the ostium of the coronary sinus in the right atrium

  • Coronary sinus lumen shows signal void due to venous blood flow

T2-weighted images:

  • Valve remains a thin hypointense structure against the hyperintense blood pool

  • Best seen in high-resolution cardiac MRI planes of the right atrium

STIR (Short Tau Inversion Recovery):

  • Fat suppression helps delineate the valve against surrounding atrial tissue

  • May highlight associated edema or fibrosis if present in pathology

T1 Post-Contrast (Gadolinium-enhanced):

  • Valve itself shows little to no enhancement (thin fibrous tissue)

  • Coronary sinus lumen enhances strongly with contrast, highlighting the valve as a filling defect

MRI Non-Contrast Cardiac-Gated 3D Coronary Imaging:

  • Valve of the coronary sinus can be seen as a small, low-signal flap at the venous ostium

  • Useful for anatomical mapping before CRT device placement or complex atrial interventions

CT Appearance

Non-contrast CT:

  • Difficult to visualize directly due to its thin structure

  • Coronary sinus is identifiable as a tubular soft tissue density in the atrioventricular groove

CT Coronary Angiography (CCTA):

  • Valve may be seen as a thin crescentic filling defect at the ostium of the coronary sinus

  • Contrast opacifies the coronary sinus lumen, highlighting the valve as a thin flap

  • Particularly important for pre-procedural planning in CRT lead insertion, ablation therapy, and venous mapping

CT image

Valve of coronary sinus anatomy CT axial image -img-00000-00000

MRI image

Valve of coronary sinus MRI axial image