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Aortic sinus

The aortic sinuses (also called sinuses of Valsalva) are three dilated pockets located in the aortic root immediately above the cusps of the aortic valve. Each sinus corresponds to one of the three cusps: right coronary sinus, left coronary sinus, and non-coronary sinus. The right and left coronary arteries originate from their respective sinuses, while the non-coronary sinus does not give rise to a coronary artery. The aortic sinuses play a crucial role in valve dynamics by allowing proper cusp separation during systole and facilitating valve closure during diastole. They also serve as the origin of the coronary circulation.

Synonyms

  • Sinuses of Valsalva

  • Aortic root sinuses

  • Aortic bulb

Function

  • Facilitate efficient opening and closing of the aortic valve cusps

  • Reduce mechanical stress on valve leaflets during systole and diastole

  • Allow formation of eddies of blood flow that aid valve closure

  • Serve as the origin of the right and left coronary arteries

  • Maintain coronary perfusion during diastole

MRI Appearance

T1-weighted images:

  • Aortic sinuses appear as low signal vascular lumens (flow voids)

  • Surrounding fat provides contrast, while aortic wall is low to intermediate signal

T2-weighted images:

  • Flowing blood remains a signal void

  • Pathology (e.g., sinus of Valsalva aneurysm, thrombus) may appear as hyperintense regions within the dilatation

Cine MRI (SSFP sequences):

  • Provides dynamic visualization of valve cusps and sinus expansion

  • Demonstrates blood flow vortices within the sinuses during systole and diastole

  • Useful for assessing valve function, regurgitation, aneurysm expansion, or dissection involving the root

T1 Post-Contrast (Gadolinium-enhanced):

  • Lumen enhances brightly and homogeneously

  • Aneurysms or pathological outpouchings are well-demonstrated

  • Abnormal mural enhancement may indicate inflammation, thrombus, or dissection flap

CT Appearance

Non-contrast CT:

  • Aortic sinuses appear as part of the aortic root contour

  • Calcifications of valve cusps or sinus walls appear hyperdense

  • Sinus of Valsalva aneurysms may be identified as dilatations

Contrast-enhanced CT (CT Angiography):

  • Provides excellent definition of aortic root anatomy, coronary artery origins, and valve relationship

  • Demonstrates aneurysms, dissection flaps, thrombus, or dilation

  • Essential for preoperative planning in valve replacement, TAVI, or aneurysm repair

  • Multiplanar and 3D reconstructions give precise spatial relationship of sinuses to coronary ostia

MRI images

CT image

Aortic sinus anatomy ct axial image -img-00000-00000

MRI image

Aortic sinus anatomy MRI coronal image -img-00000-00000