8. Digital subtraction arteriogram (DSA)

8. Digital subtraction arteriogram (DSA) — neck, AP projection

For a digital subtraction arteriogram, a digital image of the region is created both before and after the injection of contrast into the appropriate blood vessel. The first image is then digitally subtracted from the second, leaving only the image of the contrast-filled blood vessels, which is usually displayed as a positive print of the traditional radiographic image.

The first part of the subclavian artery lies medial to the scalenus anterior muscle. Its branches include the internal thoracic and vertebral arteries, and the thyrocervical trunk. The second part of the subclavian artery lies posterior to the scalenus anterior muscle. In this patient it gives rise to the descending scapular artery.

The common carotid artery extends superiorly from the root of the neck to the upper border of the thyroid cartilage, at which point it bifurcates into the internal and external carotid arteries.