Vascular Imaging of the Head and Neck – Case A

This case is the first of four cases that go with the vascular capstone course. On that page, there is a scrollable case that you can go through to teach you how to approach a CTA of the head in a real patient.

This case is an 80 year-old woman who presented with altered mental status. Take a look and see what you think before continuing on.

The patient in this case has subarachnoid and parenchymal hemorrhage on a noncontrast CT. Because aneurysms and vascular malformations are possible causes of subarachnoid hemorrhage, we proceeded with vascular imaging, or a CT angiogram of the head, to look for aneurysms or other possible vascular causes. Remember, for an intracranial hemorrhage you don’t need the CTA of the neck because these don’t commonly have any pathology that can explain intracranial hemorrhage.

On the CTA, you see multiple abnormal outpouchings of the intracranial vessels, otherwise known as an aneurysm. Intracranial aneurysms are abnormal outpouchings of the vessels thatt contain all the layers of the vessel wall (true aneurysms). They have a risk of rupture of several percent per year, and can be treated with surgical clipping or endovascular methods such as coils. Remember, it is common for patients to have more than one aneurysm, as is seen in this case.

Once you’ve finished this video, I recommend going back to the vascular capstone course, where you can review the other browseable cases with explanations. The capstone overview is here, if you’d like to see all the cases and videos.

Or, see all of the vascular capstone videos in the vascular imaging capstone playlist.

Vascular Imaging of the Head and Neck – Pathology

This lecture is the third part of a capstone course we have for our 4th year medical students. In the first lecture, we discussed general concepts about how to approach vascular imaging of the head and neck, including angiography, CT angiography, MR angiography, and ultrasound. The second part of the lecture covers a general search pattern for vascular imaging of the head and neck on a CT angiogram. To see more about this course, check out the full vascular capstone page. It contains interactive cases that you can scroll on your own as well as some additional videos explaining them.

In this lecture, we welcome back our special guest, Dr. Cynthia Wu, who is going to go over some of the common pathologies you might encounter on vascular imaging of the head and neck.

Common pathologies

There are a few common pathologies you might be looking for on vascular imaging of the head and neck, including aneurysm, thrombosis, dissection, and vascular malformations. Read on to learn more about each one.

Aneurysms

Aneurysms are abnormal outpouchings of the vessels. Sometimes they contain all the layers of the vessel wall (true aneurysms) or may be contained ruptures of one or more of the walls (false aneurysms, or pseudoaneurysms). Most intracranial aneurysms are true aneurysms while aneurysms in the neck are pseudoaneurysms.

Thrombosis

Thrombosis is occlusion of a vessel secondary to a blood clot. This is most commonly seen or suspected in the setting of a stroke, and can arise from rupture of an atherosclerotic plaque or from transmission of a thrombus more proximal in the circulation, such as from a cardiac valve or in the internal carotid artery. Most of the time, a thrombus will appear as abrupt severe narrowing or truncation of a vessel.

Thrombosis can also occur in veins, such as the dural venous sinuses. Venous thrombus will more commonly appear as a central filling defect.

Dissection

Dissection is a tear or injury to the lining of the artery, or intima. In this case, then blood goes into the space between the layers of the vessel wall, an area known as the false lumen. When the vessel is large enough, this vessel may fill with contrast on the injection, but in smaller vessels this may thrombose and be seen as a smooth tapering or narrowing of the vessel that can even result in occlusion. You can also sometimes get irregular enlargement of the vessel past it, or pseudoaneurysm.

Vascular malformations

Arteriovenous malformations, or AVMs, are abnormal clusters of vessels which have abnormal connections between the terminal arteries and veins. This results in a shunt, or passage of blood from an artery to a vein without a terminal capillary bed. Arteries and veins then are enlarged and at higher risk of rupture. The Spetzler Martin grading system is a grading system used to rate the risk of surgical mortality on resection which can help guide management.

What’s next?

Once you’ve finished this video, I recommend moving on to the next section of the vascular capstone, where you can review individual browseable cases with explanations. The capstone overview is here, if you’d like to see all the cases and videos.

Or, see all of the vascular capstone videos in the vascular imaging capstone playlist.

Introduction to Vascular Imaging of the Head and Neck

This lecture is the first part of a capstone course we have for our 4th year medical students about how to approach vascular imaging of the head and neck, including angiography, CT angiography, MR angiography, and ultrasound. To see more about this course, check out the full vascular capstone page. It contains interactive cases that you can scroll on your own as well as some additional videos explaining them.

In this lecture, we have a special guest, Dr. Cynthia Wu, who is going to explain to us some of the general concepts behind vascular imaging of the head and neck, different techniques you can do to perform vascular imaging, and when you might order each type of study.

Basic concepts

In general, to see vessels better on imaging, we need to use some sort of contrast to differentiate the vessels from the surrounding tissues. For techniques like CT, we can use an injected contrast agent to see the vessels. For other techniques such as MR angiography and ultrasound, we can use intrinsic properties of flowing blood to emphasize the vessels.

This section covers the key concepts behind how we see the vessels for these major techniques.

When do I order these tests?

Once you know about the different possible techniques, then you have to figure out when you would possibly order them. Each technique (CTA, MRA, and US) have different advantages and disadvantages that make them more or less suited to different scenarios.

What’s next?

Once you’ve finished this video, I recommend moving on to the next section of the vascular capstone, where you can learn a general strategy for interpreting a CT angiogram of the head and neck.

The capstone overview is here, if you’d like to see all the browseable cases and videos.

Or, see all of the vascular capstone videos in the vascular imaging capstone playlist.

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.

Overview

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:

Nonvascular structures

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.

Neck Vessels

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.

Head Vessels

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.

Summary

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.

Brain MRI – Seizure search pattern

Many times when patients have a history of seizures, they undergo a workup including a physical exam, detailed EEG analysis, and finally brain MRI to try to identify any potential structural causes of seizures. In this video, Dr. Michael Hoch walks us through his approach to a brain MRI to maximize your sensitivity for finding abnormalities.

 

Dr. Hoch suggests a 4-step approach using the mnemonic “3-2-1 go to the hippocampus”. In this way, he divides his search into more digestible parts.

“3” indicates the 3 planes that you have in a non-contrast T1 weighted MP-RAGE MRI. On this you should focus on the cortex, particularly at the 3 poles, the frontal, temporal, and occipital poles.

“2” indicates the 2 planes of FLAIR and 2 window settings you should use. You should review FLAIR images in both the coronal and axial planes. You should also use a window that is normal and a window that is narrow, or aggressive, to highlight lesions, particularly in the cortex, which are hard to see.

“1” indicates the single plane of blood sensitive imaging, either GRE or SWI, which can often see areas of prior hemorrhage or cavernou

“Go” to the hippocampus last to look for signs of mesial temporal sclerosis, which is manifested as a small hippocampus with loss of internal architecture and abnormal T2/FLAIR hyperintensity. This can be either from primary epilepsy or secondary to another lesion.

See this and other videos on our Youtube channel .

Board Review 3 – Full lecture

This lecture is a board review lecture geared towards preparation for the radiology resident ABR core exam, although similar material is used for the ABR certifying exam general and neuroradiology sections.

The format of this lecture is case-based. Each case consists of a series of images followed by 1 or 2 questions. The first question is usually to name the diagnosis, while the second is a multiple choice question to test deeper understanding of the specific condition. Try to get the diagnosis before you see the second questions.

The first 10 cases cover brain tumors and the remaining 9 cover general neuroradiology. The final case will be a high speed multiple choice review.

Noncontrast MRI cervical spine search pattern

Magnetic resonance imaging (MRI) of the cervical spine is a very commonly encountered test which can be performed for a variety of indications, including degenerative disease, trauma, demyelinating disease, and metastatic disease. Most of these cases will be done without contrast, as most of the information is there on a non-contrast exam.

This video will walk you through a step-by-step approach to evaluating an MRI of the cervical spine. The optimal approach is to use select sequences to evaluate each part of the study in the following order:

Alignment
Vertebral bodies
Marrow signal
Intervertebral discs
Spinal cord/canal
Soft tissues
Individual levels

Each sequence in the study has strengths at looking at one or more of these things. As we walk through, we’ll take a look at how to use each one.

The level of this lecture is appropriate for medical students, junior residents, and trainees in other specialties who have an interest in neuroradiology or may see patients with spine diseases.

See this and other videos on our Youtube channel.

CT (computed tomography) face radiology search pattern

When you start taking call as a radiology resident, a common test you are going to encounter is a maxillofacial CT, or face CT. This is especially true if you are taking call at a level 1 or level 2 trauma center. A lot of times, this is done in conjunction with a head and/or cervical spine CT. This is an extremely common test in the setting of trauma, including assault and car accidents (MVA or MVC). The key in these settings is to rule out a significant fracture or soft tissue injury to the face.

Because there are a lot of structures, it is important to have a useful search pattern. Reconstructions, especially the coronal reconstruction, are key when interpreting CT of the face. These allow you to see key structures that are parallel to the slice plane on axial images. Symmetry is extremely helpful, as the left should match the right. Additionally, making sure all the fat and fascia planes are clean is very useful.

This video will walk you through a step-by-step approach to evaluating a CT of the face. I recommend a pattern where you start with the coronals at the cranial (top) part of the image, and then work your way down. In this way, you can look at the brain, orbits, sinuses, palate, mandible, and so forth, minimizing the risk of missing a significant finding. Then you can repeat the pattern with the axial images. Finally, the sagittal images are a nice troubleshooting tool, especially for the mandible and cervical spine. As you practice, you will find you can move more quickly through your search without necessarily focusing on each individual element for too long.

The level of this lecture is appropriate for medical students, junior residents, and trainees in other specialties who have an interest in neuroradiology or may be involved with patients with facial injuries and other abnormalities.

 

See this and other videos on our Youtube channel.

Board Review 2 – Full lecture

This lecture is a board review lecture geared towards preparation for the radiology resident ABR core exam, although similar material is used for the ABR certifying exam general and neuroradiology sections.

The format of this lecture is case-based. Each case consists of a series of images followed by 1 or 2 questions. The first question is usually to name the diagnosis, while the second is a multiple choice question to test deeper understanding of the specific condition. Try to get the diagnosis before you see the second questions.

These are all general neuroradiology questions.