Left Subclavian Artery
When your doctor orders a CT scan, or other imaging study, you might see “left subclavian artery” mentioned in the radiology report. This important blood vessel plays an important role in supplying blood to your left arm and parts of your brain. This article will discuss what radiologists look for when examining this artery so that you can better understand your medical imaging reports.
What Is the Left Subclavian Artery
The left subclavian artery is one of the major blood vessels that branches directly from your aorta, the body’s main artery. Located in your chest, this artery runs beneath your left collarbone and extends toward your left arm. Think of it as a highway that carries oxygen-rich blood from your heart to your left shoulder, arm, and hand.
This artery also gives rise to several smaller branches that supply blood to parts of your brain, neck muscles, and chest wall. The vertebral artery, which helps supply your brain stem and cerebellum, branches off from the left subclavian artery early in its course.
How the Left Subclavian Artery Appears on Medical Imaging
On chest X-rays, the left subclavian artery typically appears as part of the mediastinal silhouette, the shadow created by structures in the middle of your chest. Radiologists look for its normal position and any unusual widening or irregularities in its outline.
CT scans provide much more detailed images of the left subclavian artery. With contrast dye, this artery lights up clearly, allowing doctors to see its exact shape, size, and any potential blockages or abnormalities.
Special MRI sequences called MR angiography can create detailed pictures of this blood vessel, showing how blood flows through it.
Common Left Subclavian Artery Findings on Radiology Reports
When radiologists examine the left subclavian artery, they look for several key features. Normal findings include appropriate size, smooth walls, and proper positioning relative to other chest structures.
Atherosclerosis represents one of the most common abnormal findings. This condition involves plaque buildup inside the artery walls, which can narrow the vessel and reduce blood flow. On imaging, atherosclerosis may appear as calcified deposits or areas where the artery wall looks thickened or irregular.
Subclavian steal syndrome is another condition that imaging can detect. This occurs when blockage in the subclavian artery causes blood to flow backward through the vertebral artery, potentially reducing blood supply to the brain. Doppler ultrasound studies can show this reversed blood flow pattern.
Left Subclavian Artery Stenosis and Blockages
Stenosis means narrowing of the artery, and it can occur in the left subclavian artery due to various causes. Atherosclerosis is the most common reason, but other conditions like arteritis or external compression can also cause narrowing.
On CT angiography, stenosis appears as areas where the artery diameter is reduced compared to normal segments. Radiologists measure the degree of narrowing as a percentage, with significant stenosis typically defined as 50% or greater reduction in diameter.
Complete blockage or occlusion of the left subclavian artery may show up as an area where no contrast flows through the vessel. In these cases, the body often develops collateral circulation, where smaller arteries expand to carry blood around the blocked area.
Subclavian Artery Aneurysms on Imaging Studies
An aneurysm is an abnormal bulging or enlargement of an artery wall. Left subclavian artery aneurysms are relatively uncommon but can be serious if they grow large or rupture.
On imaging, aneurysms appear as focal enlargements of the artery. CT scans are good at showing the exact size and shape of aneurysms, while also revealing any surrounding inflammation or compression of nearby structures.
Anatomical Variations of the Left Subclavian Artery
Some people are born with anatomical variations in how their subclavian artery connects to the aorta. The most common variation is an aberrant right subclavian artery, but occasionally the left subclavian artery may have an unusual origin or course.
These variations usually don’t cause symptoms but can be important for surgeons to know about before certain procedures. Radiologists carefully note these anatomical differences in their reports.
Trauma and the Left Subclavian Artery
Chest trauma from car accidents, falls, or other injuries can damage the left subclavian artery. CT scans performed after trauma often include special attention to this vessel, looking for signs of injury like bleeding around the artery or disruption of its normal appearance.
Blunt trauma can cause the artery to tear or develop a pseudoaneurysm, where blood leaks out but is contained by surrounding tissues. These injuries require prompt recognition and treatment to prevent life-threatening complications.
When Additional Testing Is Needed
Sometimes initial imaging raises questions about the left subclavian artery that require additional tests. If a chest X-ray shows an unusual mediastinal contour, a CT scan with contrast might be ordered for better visualization.
Doppler ultrasound studies can assess blood flow through the subclavian artery and detect problems like stenosis or steal syndrome. This non-invasive test uses sound waves to create images and measure blood velocity.
Conventional angiography, where contrast dye is injected directly into arteries through a catheter, provides the most detailed images of the subclavian artery. This test is usually reserved for cases where treatment might be needed or when other imaging methods don’t provide clear answers.
Treatment Implications of Left Subclavian Artery Findings
The findings on imaging studies of the left subclavian artery directly influence treatment decisions. Mild atherosclerosis might be managed with medications and lifestyle changes, while severe stenosis could require angioplasty or surgical bypass.
Radiologists typically note this finding when there’s significant narrowing that could affect blood flow to the arm or brain, as this often indicates the need for vascular specialist consultation and possible intervention.
Conclusion
Understanding what radiologists look for when examining the left subclavian artery on imaging studies helps patients become more informed participants in their healthcare. Whether the findings show normal anatomy, atherosclerosis, stenosis, or other conditions, clear communication between radiologists, referring physicians, and patients ensures appropriate follow-up and treatment. If your radiology report mentions the left subclavian artery, don’t hesitate to ask your doctor to explain the findings and their significance. Early detection and proper management of subclavian artery problems can prevent serious complications.
References
- https://pubs.rsna.org/doi/full/10.1148/rg.220064
- https://www.verywellhealth.com/subclavian-artery-5094725
- https://ajronline.org/doi/10.2214/AJR.15.15685