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Anatomy and Anatomic Variants
What are some common anatomic variants of peripheral arterial system.
a. Absence of anterior or posterior tibial arteries (5% of individuals).
b. High origin of radial artery from the axillary or brachial artery (17% of patients).
c. Persistent sciatic artery (normal fetal branch of internal iliac artery that continues into lower extremity).
What is the most common arch anomaly? What percentage of the population present with this anatomic variant?
a. Left arch with aberrant right subclavian artery.
b. 2% of population.
What are the most common congenital aorta arch anomalies seen in an adult vascular radiology practice?
Left-sided (normal) arch with aberrant right subclavian artery. Pseudocoarctation (aortic kink) of thoracic aorta.
What is a diverticulum of Kommerell?
Dilation at origin of aberrant right subclavian artery. May impress esophagus, resulting in dysphagia.
What is a pseudocoarctation (aortic kink)?
Mild form of coarctation, hemodynamically insignificant stenosis. Infolding occurs near ligamentum arteriosum. Pressure gradient across the kink less than 10 mm Hg.
What is the most common site for upper-extremity atherosclerotic involvement? How may these patients present?
Proximal left subclavian artery can result in subclavian steal.
What/Where is the most common aneurysm outside of aorta and iliac arteries?
Splenic artery aneurysm.
A left SVC occurs in ______ of the population and descends through the left mediastinum anteriorly to join the _______, which drains into the RA
b. coronary sinus
What can lead to azygos continuation of the IVC?
Absence of intrahepatic portion of the IVC. Failure of right subcardinal vein to anastomose with hepatic veins. Hepatic veins drain into RA. Renal and iliac veins drain via azygos and hemiazygos veins into SVC.
Describe the characteristics of a retroaortic left renal vein and a circumaortic left renal vein.
a. Retroaortic left renal vein (2%) crosses behind aorta.
b. Both retroaortic and preaortic renal veins form the circumaortic left renal vein (8%).
What is the coronary vein portosystemic shunt pathway?
The coronary vein portpsystemic shunt communicates with the azygos system in the submucosa of the distal esophagus and gastric cardia.
The femoral vein is a continuation of the popliteal vein at the ______.
What are the three (3) collateral communications of mesenteric arteries?
Marginal artery of Drummond:
- Anastomosis between right colic, right and left branches of middle colic, and left colic arteries. Found along mesenteric border of colon. Important collateral supply in IMA occlusions.
Arc of Riolan:
- Variable communication between SMA and IMA. Located more centrally than marginal artery.
Arc of Buehler:
- Short, ventral artery between main celiac and SMA. Persistent fetal communication.
What are the most common traumatic aortic injury sites?
Proximal ascending aorta. Just beyond left subclavian (aortic isthmus). Just above the level of the diaphragm.
What are the keys to help distinguish a ductus bump from a contour abnormality at the aortic isthmus (5)?
a.Ductus bump is very smooth and convex without acute margins.
b. Aortic tear has acute margins and irregularly shaped.
c. May have associated Luminal narrowing. Persistence of contrast in the outpouching.
d. Double densities.
e. Intimal flap.
Where do posttraumatic thoracic aortic aneurysms most often occur?