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Topic

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Ascending aorta

The ascending aorta is the first section of the thoracic aorta, arising from the aortic valve annulus at the left ventricle. It extends upward and slightly forward within the pericardial sac, ending at the origin of the brachiocephalic artery, where it continues as the aortic arch. The ascending aorta is divided into the aortic root (containing the aortic valve, sinuses of Valsalva, and coronary artery origins) and the tubular ascending aorta. Its elastic wall accommodates systolic ejection, maintaining continuous blood flow into systemic circulation.

Synonyms

  • Thoracic ascending aorta

  • Proximal aorta

  • Aortic root and tubular ascending aorta

Function

  • Carries oxygenated blood from the left ventricle to the systemic circulation

  • Gives rise to the right and left coronary arteries at the aortic root

  • Provides elastic recoil to maintain diastolic pressure and forward flow

  • Serves as the starting point of the systemic arterial tree

MRI Appearance

T1-weighted images:

  • Flowing blood produces a signal void (black lumen)

  • Aortic wall is a thin, hypointense rim relative to surrounding mediastinal fat

  • Useful for identifying aortic dimensions and wall pathology

T2-weighted images:

  • Lumen appears as signal void due to flow; surrounding mediastinum shows bright fat

  • Wall edema, intramural hematoma, or inflammation may appear as hyperintense thickening

Cine MRI (SSFP / cine T2 sequences):

  • Provides real-time dynamic imaging of aortic root motion and valve function

  • Excellent for measuring aortic diameter during cardiac cycle

  • Detects aortic regurgitation, dissection flap motion, aneurysm expansion, and flow dynamics

T1 Post-Contrast (Gadolinium-enhanced / MRA):

  • Lumen demonstrates homogeneous bright enhancement

  • Essential for identifying aneurysms, dissection, coarctation, or mural thrombus

  • High-resolution MRA provides accurate vascular mapping for preoperative assessment

CT Appearance

Non-contrast CT:

  • Ascending aorta appears as a tubular soft tissue density anterior to the pulmonary trunk and right atrium

  • Calcifications in aortic wall or valve annulus appear hyperdense

  • Intramural hematomas can appear as high-attenuation crescentic wall thickening

Contrast-enhanced CT (CT Angiography):

  • Provides excellent delineation of lumen, wall, and branching vessels

  • Gold standard for detecting aortic aneurysm, dissection, ulceration, or post-surgical graft integrity

  • Multiplanar and 3D reconstructions allow accurate measurement of aortic diameters and surgical planning

MRI images

Ascending aorta anatomy MRI coronal image -img-00000-00000

CT image

Ascending aorta anatomy CT axial image -img-00000-00000

CT image

Ascending aorta Anatomy, Location and Imaging Appearance CT anatomy image -img-00000-00000