Multiple sclerosis – white spots and red flags – part 2

Mimics and Variants

Demyelinating disease is a common situation we encounter in neuroradiology, and properly diagnosing and tracking it using MRI is a key skill for neuroradiologists. In this second part of the lecture, Dr. Michael Hoch gives us some tips about other causes of white matter lesion, and information we can use to make our imaging diagnosis of multiple sclerosis more specific.

Clinical history has an important role in determining how specific imaging findings are for multiple sclerosis. Some features may suggest that a patient does not have multiple sclerosis, such as if they are the wrong age (< 20 or > 50 years old), if they have abrupt swift progression, if they have systemic symptoms such as fever or weight loss, and if they have uncommon CNS symptoms such as a movement disorder or meningitis signs. MS lesions also usually occur in some specific locations, such as in the corpus callosum, temporal lobe, periventricular white matter, and juxtacortical white matter.

Mimics of Multiple sclerosis

So, what are some of the common mimics of MS?

Migraine – migraine is the most common cause of non-specific white matter abnormalities in young patients, occurring in more than 50% of patients with migraine

Chronic small vessel ischemia – more common with increasing age, and worsening with risk factors such as diabetes, hypertension, and smoking

CNS vasculitis – an inflammatory syndrome of the intracranial vessels. Be on the lookout if someone has a history of TIAs or thunderclap headache, or systemic symptoms.

Behcet’s disease – a vasculitis most common in young males, characterized by brainstem involvement and oral ulcers

Susac syndrome – an autoimmune microangiopathy overlapping MS in age distribution. However, patients more often have a triad of encephalopathy, hearing loss, and visual changes. Corpus callosum involvement is more likely to be central. 

CADASIL – an autosomal dominant syndrome characterized by frequent infarcts. Look out for the characteristic locations in the temporal poles, external capsules, and paramedian superior frontla lobes. It is also usually quite symmetric.

Other rarer mimics are Neuro-Sweets disease and Lyme disease, which can cause white matter abnormalities.

Key take home points of this lecture include:

  • Multiple sclerosis is a clinical diagnosis, not an MRI diagnosis
  • White spot lesion location matters
  • Juxtacortical lesions must touch the cortex
  • Aggressively window the spine to look for cord lesions
  • Leptomeningeal enhancement is possible in multiple sclerosis

Variants of demyelinating disease

There are several common variants that you should know about across the demyelinating spectrum:

ADEM – acute disseminated encephalomyelitis – an autoimmune mediated and often self limited fulminant demyelinating process. May be related to a viral illness or vaccination.

Marburg disease – a clinically fulminant demyelinating disease usually affecting younger patients with a febrile prodrome.

Balo concentric sclerosis – a rare and monophasic demyelinating disease characterized by large lesions with alternating zones of demyelination/myelination

Tumefactive demyelinating lesions (TDL) – large and often fulminant demyelinating lesions that have mass effect and can mimic tumors. Perfusion imaging with low blood volumes can help differentiate from masses.

Neuromyelitis optica (NMO) – a demyelinating syndrome characterized by post-chiasmatic optic neuritis and long segment spine lesions. This is mediated by an aquaporin-4 antibody.

Progressive multifocal leukoencepalopathy (PML) – a JC virus mediated demyelinating lesion that occurs in immune suppressed patients. Usually has little or no enhancement and favors a subcortical location.

Summary

In summary, there are a couple of key things to keep in mind when evaluating potential demyelinating lesions:

  • Read the chart for clinical red flags
  • Look at the MRI for imaging red flags, like strokes, hemorrhages, cysts, findings that are too symmetric, subcortical, or normal
  • Remember that white matter lesions from migraine and microvascular disease are far more common that multiple sclerosis
  • NMO has differentiating features
  • PML is a rare complication of immune suppressing medications in MS patients

 

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in imaging or treating patients with potential demyelinating diseases.

This video is part of a two part series on multiple sclerosis presented by Dr. Hoch.

If you haven’t seen it already, go back and check out part 1, in which Dr. Hoch discusses the key findings of demyelinating lesions.

Multiple sclerosis – white spots and red flags

Demyelinating disease is a common situation we encounter in neuroradiology, and properly diagnosing and tracking it using MRI is a key skill for neuroradiologists. In this two part lecture, Dr. Michael Hoch instructs us on how to approach white matter abnormalities in the brain and use them towards making a diagnosis of multiple sclerosis. The first part is focused on key tips on making a diagnosis of demyelinating disease while the second is focused on potential pitfalls.

Be sure to watch them both to get the complete overview of imaging findings of common autoimmune and inflammatory conditions.

Multiple sclerosis – white spots and red flags – part 1

Making the diagnosis

Demyelinating disease is a common situation we encounter in neuroradiology, and properly diagnosing and tracking it using MRI is a key skill for neuroradiologists. Today, Dr. Michael Hoch gives the first part of a two part lecture on how to approach white matter abnormalties in the brain and use them towards making a diagnosis of multiple sclerosis.

Multiple sclerosis is a clinical diagnosis that depends on several possible presenting signs (such as depression, fatigue, vertigo, numbness or other neurological symptoms, bladder dysfunction, visual changes, or other phenomena including L’Hermitte’s sign or Uhthoff’s phenomenon) and other clinical sign (including tremor, decreased perception, hyperreflexia, and ataxia).

The imaging diagnosis of multiple sclerosis is based on the McDonald criteria, most recently revised in 2017. This requires dissemination in space, dissemination in time, and lack of an alternate explanation. You should evaluate different spaces for white matter abnormality, including the cortex, juxtacortical, subcortical and deep white matter, corpus callosum, and deep white matter, periventricular white matter. 

The locations of the lesions can provide a clue as to whether white matter lesions are more likely to be caused by demyelinating disease or other nonspecific insults, such as chronic microvascular ischemia. For instance, central lesions in the pons or lesions in the deep white matter are more nonspecific, while cortical/juxtacortical, periventricular, and anterior temporal lesions are more specific for multiple sclerosis.

The enhancement pattern is also a clue to whether a lesion might be demyelinating. Demyelinating lesions typically have an incomplete rim of enhancement, where the post-contrast enhancement has a broken circle type of appearance. Leptomeningeal enhancement can often be seen in patients with MS, although it is an alarm bell if patients don’t have a known diagnosis, as it can represent other diseases such as leptomeningeal carcinomatosis.

Key take home points of this lecture include:

  • Multiple sclerosis is a clinical diagnosis, not an MRI diagnosis
  • White spot lesion location matters
  • Juxtacortical lesions must touch the cortex
  • Aggressively window the spine to look for cord lesions
  • Leptomeningeal enhancement is possible in multiple sclerosis

 

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in imaging or treating patients with potential demyelinating diseases.

This video is part of a two part series on multiple sclerosis presented by Dr. Hoch.

For the next part of the lecture, check out part 2, in which Dr. Hoch discusses potential mimics and pitfalls when assessing for demyelinating disease.

Imaging CNS autoimmune and inflammatory disease

Spine Inflammatory Disease

This is the fourth lecture in a case based review of imaging of the brain and spine for autoimmune and inflammatory conditions. We will cover the MRI findings of some of the common conditions and some potential pitfalls and mimics.

This lecture covers two inflammatory diseases which can occur in the spinal cord: transverse myelitis and sarcoidosis. Multiple sclerosis can also cause an inflammatory myelitis, but it usually is associated with intracranial MS and has shorter segment lesions.

Transverse myelitis 

Transverse myelitis is a common infectious or inflammatory cause of myelopathy in the cervical or thoracic spine. This is most commonly manifested with long segment T2 abnormality (more than one vertebral body in length). It is commonly central and may have enhancement, particularly in the acute phase. It is often associated with a recent viral illness and can be caused by direct viral infection or as inflammatory post-viral syndrome. Treatment is largely limited to symptomatic control and immune suppression similar to treatment of multiple sclerosis.

Sarcoidosis

Sarcoid can affect the spine although it is less common that involvement of the brain. The most common manifestation in the spine is long segment T2 hyperintensity with associated enhancement. The enhancement pattern is often nodular and peripheral, which can help differentiate it from other causes of abnormal cord signal. As with sarcoidosis in the brain, you may also see nodular areas of enhancement or sarcoidomas. The diagnostic workup is similar. You should start by imaging the brain and chest to look for other potential areas of sarcoid involvement. ACE levels or IL-2 surface antigen can also be useful when available.  

Summary and Conclusion

In summary, when you have longer segment T2 hyperintense lesions in the spine, you should think about transverse myelitis or sarcoidosis. There is a broader differential which includes multiple sclerosis, lymphoma, and other tumors (such as astrocytoma or ependymoma). You may not be able to tell without other diagnostic clues, which makes imaging of the brain and correlation with the clinical scenario important.

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties, such as neurology, who have an interest in neuroradiology or may see patients with CNS demyelinating or inflammatory conditions.

Other videos on the autoimmune and demyelinating playlist are found here

Imaging CNS autoimmune and inflammatory disease

Introduction/Demyelinating disease

This is the first lecture in a case based review of imaging of the brain and spine for autoimmune and inflammatory conditions. We will cover the MRI findings of some of the common conditions and some potential pitfalls and mimics.

This first lecture covers demyelinating disease, with the most common being multiple sclerosis (or MS), neuromyelitis optica (NMO), and acute disseminated encephalomyelitis (ADEM). These are all demyelinating/autoimmune conditions in which the brain loses its normal myelination.

Multiple sclerosis

MS is the most common demyelinating disease, affecting women more than men, with 2 age distribution peaks in younger and middle age women. MS commonly presents with optic nerve or visual symptoms, affects the brain more commonly than the spine, and can result in short segment spine lesions.

Neuromyelitis optica

Neuromyelitis optica, or NMO, is an autoimmune disease characterized by predominantly optic nerve and spine lesions. It is often associated with an antibody to aquaporin 4.

Acute disseminated encephalomyelitis (ADEM)

ADEM is an acute fulminant demyelinating syndrome characterized by acute onset and often many supratentorial lesions. The majority of patients recover, although some may have residual symptoms and it can even progress to death.

Acute hemorrhagic encephalomyelitis (AHEM)

AHEM is a closely related variant of ADEM which is associated with hemorrhage.

Susac syndrome

Susac syndrome is a small vessel vasculitis with small vessel infarcts, most commonly in the retina, cochlea, and periventricular white matter and corpus callosum. It can frequently mimic demyelinating disease because the distribution of lesions is similar.

Summary and Conclusion

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties, such as neurology, who have an interest in neuroradiology or may see patients with CNS demyelinating or inflammatory conditions.

Imaging CNS autoimmune and inflammatory disease

This playlist is a case-based review of autoimmune and inflammatory conditions that can be seen in neuroradiology. MRI findings in the brain and spine are discussed. Common conditions are covered, including demyelinating disease, encephalitis, masslike disease like sarcoid and orbital inflammatory disease, spine inflammatory disease, amyloid, and vascular processes.

Be sure to watch them all to get the complete overview of imaging findings of common autoimmune and inflammatory conditions.

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.

Board Review 2 – Case 19

Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.

More description and the answer (spoiler!) are seen below the video.

This case shows a trauma patient with disruption of the arch of C1 on a CT of the cervical spine. There are injuries to both the anterior and posterior arch.

After presentation, the patient developed posterior fossa symptoms such as nausea and vertigo

The diagnosis is: Jefferson fracture with vertebral artery injury

A number of fractures in the neck have eponyms, and the Jefferson fracture is when the arch of C1 is fractured. It commonly involves injury to both the anterior and posterior arch, although this isn’t a requirement.

After high energy trauma, it is common to have injury to arteries in the neck, so it is important to consider this if a patient develops new symptoms. This patient had a traumatic wall injury of the left vertebral artery which is demonstrated on a T1 weighted fat saturated image of the neck, which showed T1 hyperintense methemoglobin in the wall.

Traumatic arterial injury is often graded using the Denver grading scale, which is as follows:

  • Grade I – < 25% narrowing
  • Grade II – > 25% narrowing or dissection flap
  • Grade III – pseudoaneurysm
  • Grade IV – occlusion
  • Grade V – transection/active extravasation

Injury can be evaluated with either CTA (more common) or MRA.

Board Review 2 – Case 16

Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.

More description and the answer (spoiler!) are seen below the video.

This case shows a mass within the spinal canal of the upper thoracic spine. For any spinal canal mass, your first step is to determine if it is:

  • intramedullary (in the spinal cord)
  • intradural extramedullary (inside the dura, but outside the spinal cord)
  • extradural

This mass appears to be extramedullary but intradural. The main differential considerations are meningioma, nerve sheath tumor/schwannoma, or metastasis. This mass has a relatively benign appearance and enhances avidly and homogenously.

The diagnosis is: meningioma

Spinal meningiomas are extramedullary masses that share an imaging appearance with intracranial meningiomas. They are often homogenous and enhance avidly. They can have calcification. The treatment, if symptomatic, is surgical resection.

Board Review 2 – Case 15

Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.

More description and the answer (spoiler!) are seen below the video.

This case shows a trauma patient who had a significant fall and now has lower extremity symptoms. On the MRI, there are a few compression fractures that you can see, but in addition there is T1 hyperintense fluid in the dorsal epidural space. In the setting of trauma, this is likely to be an epidural hematoma.

The diagnosis is: fracture with spinal epidural hematoma

Epidural hematoma is a dreaded complication of spine trauma that can cause worsening cord injury. It requires close monitoring and possibly surgical drainage if this may improve the symptoms. Look for intraspinal fluid collections after trauma, as they can be hard to identify.