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Descending thoracic aorta

The descending thoracic aorta is the continuation of the aortic arch, beginning at the level of the T4 vertebra (left of midline) and extending to the aortic hiatus of the diaphragm at T12, where it becomes the abdominal aorta. It lies posterior to the left lung and pleura, anterior to the vertebral column, and descends slightly to the left of the midline. The vessel gives off numerous branches, including the posterior intercostal arteries, subcostal arteries, bronchial arteries, and esophageal branches, which supply the thoracic wall, lungs, and esophagus.

Synonyms

  • Thoracic aorta (descending portion)

  • Pars thoracica aortae

  • Distal thoracic aorta

Function

  • Conveys oxygenated blood from the heart to the thoracic organs and body wall

  • Supplies branches to the esophagus, lungs, pericardium, and intercostal spaces

  • Serves as the main conduit between the aortic arch and abdominal aorta

  • Plays a role in systemic blood pressure regulation and flow distribution

MRI Appearance

T1-weighted images:

  • Flowing blood appears as a signal void (black lumen) in non-contrast sequences

  • Aortic wall appears as a thin low-signal rim against hyperintense mediastinal fat

  • Cine MRI can outline the aortic contour dynamically

T2-weighted images:

  • Lumen demonstrates signal void from blood flow

  • Wall pathology (dissection flap, mural thrombus, intramural hematoma) may appear as high-signal intensity areas

  • Useful for detecting aortic wall edema or intramural hematoma

Cine MRI (SSFP sequences):

  • Provides dynamic imaging of blood flow and wall motion

  • Demonstrates aortic pulsation, flow turbulence in aneurysms, or stenosis

  • Combined with phase-contrast imaging, allows quantification of flow and pressure gradients

T1 Post-Contrast (Gadolinium-enhanced):

  • Lumen shows intense homogeneous enhancement

  • Defines true and false lumens in aortic dissection

  • Detects aneurysm, stenosis, or mural irregularities with high sensitivity

CT Appearance

Non-contrast CT:

  • Aorta appears as a tubular high-density structure with soft-tissue attenuation lumen

  • Calcifications in the wall are well seen as hyperdense foci

  • Useful for detecting intramural hematoma and wall calcification

Contrast-enhanced CT (CT Angiography):

  • Gold standard for evaluating the thoracic aorta

  • Provides high-resolution imaging of the aortic lumen, wall, branches, and pathology

  • Excellent for diagnosing aortic dissection, aneurysm, stenosis, trauma, or vascular malformations

  • Multiplanar and 3D reconstructions enable precise preoperative and interventional planning

MRI image

Descending thoracic aorta mri axial

MRI image

Descending thoracic aorta MRI coronal image -img-00000-00000

CT image

Descending thoracic aorta anatomy ct axial image -img-00000-00000

X Ray image

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