Author: Brent Weinberg, MD

Spine tumors 4 – Intradural Extramedullary Lesions

Posted on by Brent Weinberg, MD

Spine tumors 4 – Intradural Extramedullary Lesions

Lesions that occur within the thecal sac are categorized as intradural extramedullary lesions. The vast majority of these lesions are tumors. The most common are schwannomas (and other nerve sheath tumors) and meningiomas, but there are others that include ependymoma, metastatic disease, and lymphoma. Also remember that the intradural extramedullary space contains cerebrospinal fluid (CSF), so any process that diffusely affects CSF can affect this space.

Peripheral nerve sheath tumors are a group of benign and malignant nerve tumors including schwannomas and neurofibromas. These can expand the neural foramen and usually have well defined margins. Schwannomas tend to enhance a lot while neurofibromas enhance less.   Sarcoidosis is another common granulomatous disease that can affect the cord. The most common appearance is T2 abnormality within the cord with some enhancement. Enhancement is often along the surface of the cord.

Neurofibromatosis is a genetic syndrome with two types, type 1 and type 2. NF type 1 is characterized by multiple plexiform (involving more than one adjacent nerve root) neurofibromas. If neurofibromas increase in size rapidly, have necrosis, or cause pain, that can be a sign of malignant degeneration. NF type 2 is characterized by multiple masses including schwannomas, meningiomas, or ependymomas. NF type 2 is sometimes called MISME syndrome.

Schwannomas are probably the most common intradural extramedullary lesions. They are well defined lesions with avid enhancement. They often have central non-enhancement or cystic degeneration, but calcification or hemorrhage are less common.

Case 1 – Meningioma. Meningiomas are well demarcated intradural lesions which occur along the dura and deflect the spinal cord. They enhance avidly and usually don’t have necrosis. They frequently calcify, which you may appreciate more on CT. If they are more elongated and plaquelike they may be referred to as “en plaque” menigiomas. They can cross the dura and have components outside the dura as well.

Case 2 – Myxopapillary ependymoma. Myxopapillary ependymomas are relatively common tumors that occur around the conus and cauda equina. They usually enhance avidly. Necrosis or hemorrhage are more common than in schwannomas. They were previously grade 1 tumors but have been upgraded to grade 2 because they frequently recur.

Leptomeningeal metastases are a consideration anytime you see multiple intradural nodules. In adults, these are most commonly from the most common tumors such as melanoma, lung, and breat cancer. Lymphoma can also occur along the cauda equina. In pediatric patients you should also think about intracranial tumors that spread in the CSF, like medulloblastoma, pineal

Case 3 – Paraganglioma. Spinal paragangliomas are rare spine tumors that have a lot of abnormal surrounding vessels and are prone to hemorrhage. Think about them anytime you see an enhancing tumor in the spine with a lot of flow voids. The other thing you might think about is a hemangioblastoma, but they are more likely to be cystic.

Case 4 – Lipoma. Fat containing lesions along the conus are common and can be lipomas or dermoids. Clues are fat-suppression of FS images, chemical shift artifact, and fat density on CT. If it is thin and linear along the filum terminale, it is likely a benign fatty filum terminale.

Summary. Intradural extramedullary lesions are among the most common spinal lesions and it is important to have a clear differential when you see them.

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in neuroradiology or may see patients with spine tumors.

Other videos on the spine tumor playlist are found here

Spine tumors 3 – Intramedullary tumor mimics

Posted on by Brent Weinberg, MD

Spine tumors 3 – Intramedullary tumor mimics

There are a wide range of lesions occurring in the spinal cord which can mimic tumors. This includes vascular lesions, inflammatory/demyelinating disease, sarcoid, and CSF flow abnormalities. This video takes a look at some of the range of possibilities.

Cord infarcts are areas of disruption of blood flow. Primary characteristics are abnormal diffusion imaging and acute onset. Often patients have other pathology such as recent aortic surgery or aortic dissection.

Sarcoidosis is another common granulomatous disease that can affect the cord. The most common appearance is T2 abnormality within the cord with some enhancement. Enhancement is often along the surface of the cord.

Neuromyelitis optica is a demyelinating disease characterized by long segment myelitis, often in the cervical cord. It is associated with optic neuritis and abnormal anti-aquaporin antibodies.

Radiation myelopathy can happen in patients that have had radiation to the cord or surrounding region. Knowing the history is important. Radiation necrosis frequently will have less mass effect than other tumors and will respond to steroids.

Syrinx or presyrinx can occur in the setting of CSF flow obstruction. This can commonly occur with conditions such as Chiari malformation or due to a large disc bulge. A cystic syrinx can cause mass effect and mimic tumor but will rarely have enhancement.

Arachnoid adhesions or webs are special situations of CSF obstruction where an adhesion in the CSF space deflects the cord contour. Due to deflection, CSF flow within the central canal can be disrupted and cause cyst-like expansion mimicking a tumor. The characteristic finding is the “scalpel sign” where the cord contour takes on the appearance of a surgical scalpel.

Summary. History is extremely important in evaluating potential spine tumors as additional history may inform you that a lesion isn’t a tumor at all.

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in neuroradiology or may see patients with spine tumors.

Other videos on the spine tumor playlist are found here

Spine tumors 2 – Intramedullary lesions

Posted on by Brent Weinberg, MD

Spine tumors 2 – Intramedullary lesions

In this lecture in the spine tumor series, we take a look at intramedullary lesions within the spinal cord. These are lesions that are within the dura and the substance of the spinal cord.

The most common intramedullary tumors are primary tumors of the cord itself, most commonly ependymomas and astrocytomas. Other things such as hemangioblastoma and cavernous malformations can also happen in the spinal cord. For the rest of this lecture, we take a look at a few case based examples of intramedullary tumors.

Case 1 – Astrocytoma. Astrocytomas are the second most common cord tumors and the most common tumors in young adults. They frequently have enhancement. Low grade tumors (grade 2) are the most common although glioblastomas/high grade tumors can also occur.

Case 2 – Ependymoma. Ependymomas are the most common cord tumors and the most common tumors in adults. They often have a cystic appearance with a well marginated nodular lesion. Hemorrhage and a “cystic cap” are common. Ependymomas are associated with neurofibromatosis type 2.

How to differentiate astrocytomas from ependymoma. Ependymomas are usually older patients with shorter segment lesions and well-defined margins, while astrocytomas are younger patients with more ill-defined margins.

Cord glioblastoma. Intramedullary glioblastoma has the same appearance as glioblastoma and appears like a high-grade lesion with mass effect, ill-defined margins, and necrosis.

Case 3 – Hemangioblastoma. Hemangioblastomas are common cord tumors and are associated with Von Hippel Lindau (VHL) syndrome. 1/3 are associated with the syndrome while 2/3 are spontaneous. Tumors often appear as a cyst with an enhancing nodule. You may see flow voids similar to those you see in the brain, although they are often harder to see. Patients with VHL may also have brain hemangioblastomas, endolymphatic sac tumors, and other systemic tumors (such as renal tumors).

Case 4 – Cavernous malformation. Cavernous malformations, sometimes referred to as cavernomas, can occur in the spinal cord. They have a similar appearance to cavernous malformations in the brain, often with a rim of siderosis and central T1 and T2 hyperintensity. Little to no enhancement is common.

Causes of hematomyelia (blood in the spinal cord). The differential for hematomyelia includes coagulation disorder, vascular malformations, anticoagulation medications, trauma, or cord tumor with repeated hemorrhage.

Take-home points.

  • The spinal cord is an extension of the brain and affected by similar pathologies
  • Tumors are the most common pathology. Astrocytomas (< 20 years old) and ependymomas (> 20 years old)
  • Other tumors can also affect the spinal cord

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in neuroradiology or may see patients with spine tumors.

Other videos on the spine tumor playlist are found here.

Spine tumors 1 – Introduction to a location-based approach

Posted on by Brent Weinberg, MD

Spine tumors 1 – Introduction to a location-based approach

Spine tumors can be a challenging topic for a neuroradiologist because we deal less with tumors in the spinal cord and spinal canal. However, there is a relatively simple approach that can hep you hone your differential diagnosis. This involves taking a location-based approach which divides the spinal canal into 3 main regions.

  • Intramedullary – in the spinal cord
  • Extramedullary intradural – in the thecal sac (within the dura) but outside the spinal cord
  • Extradural – outside the dura

Then, you can formulate your differential based on the normal structures in those regions. You can’t always tell the exactly location of a lesion, but you can use the displacement of normal structures to help you try to decide. Then you know how to guide your differential.

By the end of this video you will be able to name the three main compartments of the spine for classification of tumors. The subsequent videos will help walk you through the more specific locations using case examples and potential mimics.

Special thanks to Dr. Michael Hoch for helping with this lecture and Dr. John Loh for handing down the drawing over the generations!

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in neuroradiology or may see patients with spine tumors.

Other videos on the spine tumor playlist are found here.

Imaging Spine Tumors

Posted on by Brent Weinberg, MD

Imaging Spine Tumors

Spine tumors can be a challenging topic for a neuroradiologist because we deal less with tumors in the spinal cord and spinal canal. However, there is a relatively simple approach that can hep you hone your differential diagnosis. This involves taking a location-based approach which divides the spinal canal into 3 main regions. This series of videos shows the general approach as well as specifics about making a differential diagnosis in each of these locations.

Be sure to check back often as more videos are added that cover your favorite neuroradiology exams, or check out our full channel on Youtube.

Vascular Imaging of the Head and Neck – Case D

Posted on by Brent Weinberg, MD

Vascular Imaging of the Head and Neck – Case D

his case is the fourth and final case that goes 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 a 41 year-old man after a trauma in a motor vehicle collision (MVC). Take a look and see what you think before continuing on (https://bit.ly/CTAcaseD).

Starting with the CTA of the neck, this is not a normal case. If you follow your normal search pattern, you will see that there are a number of abnormalities, starting from the right internal carotid artery (ICA), which is lumpy and irregular looking. The left ICA is worse, with areas of narrowing, outpouchings, and linear filling defects that represent little areas of the intima that are lifted up by trauma. The little outpouchings along the margins of the vessel are little pseudoaneurysms, or areas where the vessel is injured and contrast is able to leak out into the surrounding area of damaged vessel. Both vertebral arteries are also abnormal with multifocal irregularity and a small pseudoaneurysm on the right.

This is a dramatic example of traumatic vascular injury in the neck. After high energy or penetrating (think gunshot or stab wound), the great vessels can be injured and jeopardize the blood supply to the brain. These injuries are graded on the Denver, or Biffl, scale which ranges from 1-5. You can read more about it on Radiopaedia. Injuries to the vessels in the neck are most commonly pseudoaneurysms, meaning that one layer or more of the vessel is injured and the wall of the aneurysm does not contain all the layers (intima-media-adventitia). Contrast this to intracranial aneurysms, which are true aneurysms and the wall contains all the layers.

This is the last of the case examples for the vascular capstone course. If you haven’t already, 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 – Case C

Posted on by Brent Weinberg, MD

Vascular Imaging of the Head and Neck – Case C

This case is the third 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 a 43 year-old woman with seizure. Take a look and see what you think before continuing on ( https://bit.ly/CTAcaseC).

On the noncontrast CT, you see some high density material in the right frontal lobe. It is more dense than contrast, which is consistent with calcium. If you look more closely at the morphology, it is almost curvilinear or tubular, giving the impression that it might be calcification along vascular structures. The sulci of the frontal lobe are effaced with masslike effect on the brain.

While the diagnosis is uncertain, there are enough features to make us think that there is an underlying vascular malformation. To check, we need to do some sort of vascular imaging. The most readily available and fastest is to do a CT angiogram.

On the CT angiogram, the proximal vessels are normal, but the abnormalities start at the proximal middle cerebral artery (MCA) and anterior cerebral artery (ACA) on the right. There are too many vessels in this region and they are too tortuous. If you follow them up, they go to a large and tortuous vascular abnormality in the right frontal lobe.There are enlarged draining veins that empty into the superior sagittal sinus.

This is the classic imaging appearance of arteriovenous malformation (AVM) within the brain. AVMs are congenital vascular abnormalities that consist of an abnormal connection of arteries and veins with a tangle of abnormal vessels, the nidus. Go on and look at the volume rendered (VR) reconstruction and the coronal maximum intensity projection (MIP) images to better understand what this abnormality looks like.

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 – Case B

Posted on by Brent Weinberg, MD

Vascular Imaging of the Head and Neck – Case B

This case is the second 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 a 47 year-old woman with new neurologic symptoms. Take a look and see what you think before continuing on (https://bit.ly/CTAcaseB).

The patient in this case has scattered small infarcts in the left MCA distribution on diffusion weighted imaging from an MRI (top left window). This raises suspicion for an underlying vascular abnormality. Remember, for stroke and vascular supply issues, you want to include CTA of the neck because these vessels supply the vessels of the circle of Willis.

On the CTA, you see multiple abnormalities. The right internal carotid artery (ICA) is tortuous and irregular in the superior neck, which is highly atypical for a patient of this age. The left internal carotid artery (ICA) is even more abnormal, with smooth tapering of the vessel to severe narrowing just above the bifurcation. The low density filling defect is thrombus, some of which is probably under a dissection flap and some of which is free-floating in the vessel. The more distal ICA also has tortuosity and narrowing similar to the right, confirming the abnormality is bilateral.

Don’t forget to complete your search pattern, but the vertebral arteries and intracranial vessels are pretty normal.

Given the multiple areas of vascular narrowing of the cervical carotid in a middle age woman with an ICA dissection on the left, this patient most likely has fibromuscular dysplasia (FMD). Fibromuscular dysplasia is the most common vasculopathy in middle-aged women and frequently affects the renal arteries, ICAs, and vertebral arteries. Characteristic findings are the beads on a string appearance of the vessel with multifocal areas of narrowing interspersed with dilation.

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 – Case A

Posted on by Brent Weinberg, MD

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

Posted on by Brent Weinberg, MD

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.