Imaging Pearls ❯ Chest ❯ Aorta and Anatomy
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- “The IMA is an elastic artery which arises from the subclavian artery. In adults the diameter of the IMA varies from 1.9 to 2.6 mm, with a wall thickness of 180 to 430 microns. The intima consists of endothelium with some neointima, which is seen in up to 50% of cases and rarely (13%) is there a substantial neointima which is greater than the medial thickness. The media consists of discreet lamellae of collagen and smooth muscle cells (SMCs) that are located between the elastic layers and are aligned circumferentially. The number of elastic layers varies from 7 to 11, depending upon the thickness of the wall of the IMA. The adventitia has been shown to possess very few vasa vasorum.”
Why is the mammary artery so special and what protects it from atherosclerosis?
Fumiyuki Otsuka, Kazuyuki Yahagi, Kenichi Sakakura, Renu Virmani
Ann Cardiothorac Surg 2013;2(4):519-526
- “The IMA is an elastic artery which arises from the subclavian artery. In adults the diameter of the IMA varies from 1.9 to 2.6 mm, with a wall thickness of 180 to 430 microns. The intima consists of endothelium with some neointima, which is seen in up to 50% of cases and rarely (13%) is there a substantial neointima which is greater than the medial thickness. The media consists of discreet lamellae of collagen and smooth muscle cells (SMCs) that are located between the elastic layers and are aligned circumferentially. The number of elastic layers varies from 7 to 11, depending upon the thickness of the wall of the IMA. The adventitia has been shown to possess very few vasa vasorum.”
Why is the mammary artery so special and what protects it from atherosclerosis?
Fumiyuki Otsuka, Kazuyuki Yahagi, Kenichi Sakakura, Renu Virmani
Ann Cardiothorac Surg 2013;2(4):519-526
- “Thoracic endovascular aortic repair (TEVAR) has evolved as an alternative to open repair for a range of aortic pathology. The earliest endovascular repairs were limited to descending thoracic aortic pathology, but growing experience has resulted in the use of stents in the ascending aorta and aortic arch. This review presents the current literature pertaining to thoracic endoluminal stent repair, with emphasis on the role of intravenous contrast-enhanced multidetector computed tomography, the primary cross-sectional imaging modality used in these patients. Radiologists play an integral role in patient selection, procedural planning, and postprocedural follow-up.”
Thoracic endovascular aortic repair: literature review with emphasis on the role of multidetector computed tomography
Johnson PT, Black JH, Zimmerman SL, Fishman EK
Semin Ultrasound CT MR 2012 Jun; 33(3):247-64 - “This review presents the current literature pertaining to thoracic endoluminal stent repair, with emphasis on the role of intravenous contrast-enhanced multidetector computed tomography, the primary cross-sectional imaging modality used in these patients. Radiologists play an integral role in patient selection, procedural planning, and postprocedural follow-up.”
Thoracic endovascular aortic repair: literature review with emphasis on the role of multidetector computed tomography
Johnson PT, Black JH, Zimmerman SL, Fishman EK
Semin Ultrasound CT MR 2012 Jun; 33(3):247-64
- “C” - Double aortic arch
- Rare anomaly caused by persistence (to varying degree) of the fetal double aortic arch system.
- The ascending aorta divides into two arches that pass to either side of the esophagus and trachea and reunite to form the descending aorta.
- Form of complete vascular ring, resulting in noncardiac morbidity, but rarely associated with intracardiac defects.
- The descending aorta is usually on the left side.
- Most commonly, one arch is dominant, whereas the other may be of small caliber or represented by a fibrous band - “A” - Right AA with mirror image branching
The mirror-image type of the right aortic arch (left brachiocephalic trunk, right common carotid and subclavian arteries) is almost always associated with congenital heart disease, especially the cyanotic type. - “B” - Right AA with aberrant left subclavian artery
- Right aortic arch is an uncommon anatomical anomaly that occurs in <0.1% of the population.
- The most common type is the right aortic arch with an aberrant left subclavian artery
- The vessels originate in the following order: left common carotid, right common carotid, right subclavian, and left subclavian artery.
- Symptoms may arise from vascular ring formation as congenital heart disease is rare in this variant. - “D” - Left AA with aberrant right subclavian artery
- The right subclavian artery is the last branch of the aortic arch in l% of individuals.
- It courses to the right behind the esophagus in 80% of these cases, between the esophagus
and trachea in 15%, and anterior to the trachea or mainstem bronchus in 5%.
- A retroesophageal course may be the cause of so-called dysphagia lusoria.
- Another variant - aberrant right brachiocephalic artery is rare - Vascular Ring Hierarchy
- If abnormal combination of derivatives of the aortic arch system results in encirclement of
the trachea and the esophagus it is often referred to as “vascular ring”.
- International Congeital Heart Surgery Nomenclature And Database Committee
Classification:
- Double aortic arch
- Right arch dominant
- Left arch dominant
- Balanced arches
- Right aortic arch–left ligamentum
- Mirror-image branching
- Retroesophageal left subclavian artery
- Circumflex aorta
- Pulmonary artery sling - Normal Anatomy
- Predominant human anatomy is a left aortic arch with three great vessels; first, the
brachiocephalic trunk, then the left common carotid artery and finally the subclavian artery.
This pattern occurs in 65-80% of the cases.
- A common brachiocephalic trunk, so-called “bovine trunk”, in which both common carotid
arteries and the right subclavian artery arise from a single trunk off the arch, occurs in 10 to
22% of individuals and accounts for more than two thirds of all arch vessel anomalies. - Double Aortic Arch: Facts
- Most common symptomatic vascular aortic arch
- The right arch is larger , posterior, ad more cephalad than the left arch in two thirds of patients and the descending aorta is usually contralateral to the dominant arch
- Trachea compression is common
- Descending aortic diverticulum (Kommerell) is not uncommon - Aberrant left subclavian artery: facts
- Left subclavian arise as last arch vessel and crosses right to left (patient has right sided arch) and posterior to the esophagus
- Bulblike dilatation of abberrant subclavian can occur and is called diverticulum of Kommerell
- When large the diverticulum of Kommerell can cause symptoms of dysphagia - Aortic Arch Anomalies
- Aberrant left subclavian artery
- Mirror image branching
- Right aortic arch with left descending aorta
- Right aortic arch with aberrant branchiocephalic artery
- Right aortic arch with isolated left subclavian artery
- Double aortic arch
- Cervical aortic arch - Anomalies of the Aortic Arch: facts
- Frequency ranges from 0.5% to 3%
- Most patients asymptomatic though others may have dysphagia, dyspnea, hypertension or congestive heart failure
- Right aortic arch occurs in 0.1% of adults
- There are 6 paired arteries arising from the aortic sac during embryogenesis with the fourth left arch forming the aortic arch - CT of the Bronchial Arteries
- The bronchial arteries arise directly from the descending aorta and supply blood to the airways, esophagus and lymph nodes
- The left bronchial arteries arise from the anterior surface of the aorta or the concavity of the arch
- The right bronchial arteries arise from the posterolateral aspect of the thoracic aorta - Massive Hemoptysis: Common Etiologies
- Pulmonary TB
- Bronchogenic carcinoma
- Cystic fibrosis
- Aspergillosis Lung abscess
- Pneumonia
- Pulmonary artery aneurysm