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Aortic valve

The aortic valve is a semilunar valve located between the left ventricle and the ascending aorta. It is composed of three cusps: the left coronary cusp, right coronary cusp, and non-coronary cusp, each attached to the fibrous aortic annulus. The valve opens during systole to allow ejection of oxygenated blood into the systemic circulation and closes during diastole to prevent regurgitation into the left ventricle.

Anatomically, the left and right coronary cusps give rise to the coronary arteries from the corresponding sinuses of Valsalva. The aortic valve is supported by the fibrous skeleton of the heart and functions in coordination with the mitral valve to maintain unidirectional blood flow.

Clinically, it is commonly involved in aortic stenosis, aortic regurgitation, congenital bicuspid aortic valve (BAV), infective endocarditis, and prosthetic valve complications.

Synonyms

  • Aortic semilunar valve

  • Valve of aorta

  • Cuspidal valve of aorta

Function

  • Opens during ventricular systole to permit blood flow from left ventricle to aorta

  • Closes during diastole to prevent backflow into left ventricle

  • Maintains systemic circulation and cardiac efficiency

  • Plays a central role in hemodynamic stability

MRI Appearance

T1-weighted images:

  • Valve leaflets appear as thin hypointense structures at the LVOT–aortic junction

  • Blood pool is hyperintense with contrast, hypointense without

T2 Cine (Cardiac-gated SSFP):

  • Provides dynamic visualization of valve opening and closing during cardiac cycle

  • Normal valve shows tricuspid configuration with thin, mobile leaflets

  • Pathology:

    • Aortic stenosis: restricted cusp motion, reduced orifice area

    • Aortic regurgitation: incomplete coaptation of cusps, retrograde flow jets

    • Bicuspid valve: two cusps with asymmetrical opening

T1 Post-Contrast (Gadolinium-enhanced):

  • Valve leaflets enhance poorly (fibrous tissue)

  • Perivalvular abscesses, pannus formation, or prosthetic valve complications may enhance

  • First-pass perfusion helps visualize retrograde flow in aortic regurgitation

MRI Non-Contrast 3D Cardiac-Gated Imaging:

  • ECG-gated, whole-heart 3D MRI provides high-resolution structural visualization of the aortic root and valve without contrast

  • Identifies number of cusps, annular morphology, and leaflet thickening/calcification

  • Useful in congenital anomalies (BAV), pre-surgical planning, and patients with renal dysfunction

MRA (Magnetic Resonance Angiography):

  • Contrast-enhanced MRA delineates the aortic root, ascending aorta, and coronary artery origins

  • Indirectly useful for assessing valve function and associated vascular pathology

CT Appearance

CT Coronary Angiography (CCTA):

  • Gold-standard non-invasive modality for valve morphology and calcification

  • Demonstrates valve anatomy, cusp number (tricuspid vs bicuspid), leaflet thickening, and calcification

  • Accurately quantifies aortic valve calcium score (important for TAVI/TAVR planning)

  • Assesses aortic annulus, root dimensions, coronary ostia, and ascending aorta

  • Cine CCTA allows dynamic assessment of valve motion and regurgitant flow

MRI image

Aortic valve MRI image

CT image

Aortic valve anatomy CT axial image -img-00000-00000_00001