How to read a CT angiogram (CTA) of the Head and Neck
With increasing ability to image vascular phenomena, such as stroke and vascular malformations, through the use of very efficient and high speed computed tomography scanner (CT), we now have the ability to perform angiographic imaging of large segments of the body at one time. This has led to an explosion of vascular imaging of the head and neck to look for a variety of pathologies, including stroke, vascular malformations, and other vascular abnormalities. Every starting radiology resident needs a firm foundation in how to interpret these images.
Because there are a ton of images and a ton of structures that you need to look at, you really need a regimented approach, or search pattern, to use as you look through the images. In this video, I teach you how to look at a CT angiogram of the head and neck from start to finish so you can learn how to do it yourself. There are interactive examples that you can follow along on the vascular capstone page.
In this video, we go through a normal example.
I divide the study into the CTA of the neck, which I review first, and the CTA of the head, which I review second. My pattern goes as follows:
I first like to look at all the nonvascular structures to make sure I’m not missing anything. I look at the lungs, the thyroid, the soft tissues of the neck (particularly to look for lymph nodes or mucosal masses), and the brain. I use a soft tissue window to look at these. Then I go back through with a bone window to look at the bones.
For the vessels of the neck, I use an approach that first does anterior vessels and then posterior vessels, moving from right to left. I follow the right common carotid artery through the bifurcation, and then follow the internal carotid to the skull base. I then repeat this pattern for the left carotid system. Then, I start from the right vertebral origin and follow it up to the skull base. Then the left vertebral artery. Once I’m finished, I restart at the skull base.
For the vessels of the head, I follow a similar approach. I first follow the right ICA through the carotid terminus and then follow the right middle cerebral artery (MCA) and anterior cerebral artery(ACA). Once finished, I return to the skull base and repeat this pattern on the left. I then move to the posterior circulation, where I first follow the right vertebral artery, the basilar artery, and the right posterior cerebral artery (PCA). Then I repeat it on the left. My final search is to quickly look at the deep venous sinuses.
While others may have a different strategy, the most important part is to have a strategy and stick to it. This pattern of dividing the study into discrete sections will help you see all the findings and describe them accurately when reading cases on your own.
See all of the search pattern videos on the Search Pattern Playlist.