Board Review 3 – Case 6

Posted on April 2, 2020April 5, 2020 by Brent Weinberg, MD

Board Review 3 – Case 6

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 young adult who underwent precocious puberty. There is an expansile, non-enhancing mass in the region of the hypothalamus/tuber cinereum.

The diagnosis is: hypothalamic hamartoma

Hypothalamic hamartomas are disorderly (hamartomatous) collections of neurons in the hypothalamic/suprasellar region. They most commonly occur just behind the optic chiasm and pitutitary infundibulum. Many times, they will present with unusual symptoms like early puberty (most common) or seizure (even with uncommon seizures like laughing “gelastic” seizures or crying seizure).

The differential diagnosis for masses in this region include astrocytoma, craniopharyngioma, and germinoma. The most common overall mass in this region is craniopharygioma, but these commonly enhance avidly, have a mix of solid and cystic regions, and can calcify.

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Board Review 3 – Case 5

Posted on March 31, 2020March 30, 2020 by Brent Weinberg, MD

Board Review 3 – Case 5

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

This case shows multiple hemorrhagic and hyperdense masses on a CT. They are predominantly supratentorial, have some edema, and are numerous.

On MRI, the regions have areas of susceptibility (dark T2 signal on GRE), surrounding edema, and enhance avidly.

The diagnosis is: metastatic disease

Intracranial metastases are extremely common and should be considered any time there are multiple masses (although 50% may be solitary). They can have hemorrhage and almost always enhance on post-contrast imaging. The most common locations are supratentorial and at the gray white junction because of the high vascularity there.

Metastases are treated with surgery or radiation. If there is oligometastatic disease (less than 10-20 lesions), stereotactic radiosurgery may be performed. Numerous lesions or leptomeningeal disease can require whole brain radiotherapy.

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Board Review 3 – Case 4

Posted on March 29, 2020March 25, 2020 by Brent Weinberg, MD

Board Review 3 – Case 4

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

This case shows an expansile extra-axial mass along the left frontal and parietal calvarium. On CT, it is hyperdense to the adjacent brain and it is causing mass effect and edema in the surrounding brain.On MRI, it is relatively T2 homogenous, appears to be arising outside the brain, and enhances homogenously and avidly.

The diagnosis is: meningioma

Aggressive extra-axial lesions, particularly those causing cortical destruction, have a differential including metastasis, meningioma, lymphoma, and myeloma. You may not be able to differentiate these by imaging.

Meningiomas are the most common brain tumors and most common extra-axial masses. They range in aggressiveness from WHO grade 1 (typical), grade 2 (atypical), and grade 3 (anaplastic), which is determined primarily on histologic features and not imaging criteria. Grade 1 tumors are treated with resection while grades 2 and 3 receive resection followed by radiation therapy.

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Board Review 3 – Case 3

Posted on March 27, 2020March 25, 2020 by Brent Weinberg, MD

Board Review 3 – Case 3

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

This case shows a nodular mass along the right frontal calvarium in a patient with pain. It is T2 hyperintense, T1 hypointense, and enhances avidly.

The diagnosis is: skull metastasis

Any mass in the calvarium that has associated osseous destruction is concerning. Benign masses often contain fat (are T1 hyperintense and suppress on T2 fat-saturated imaging) and rarely destroy the cortex. Pain, as was experienced by the patient in this case, is also a concerning feature.

Any patient with a concerning calvarial mass but no history of malignancy should probably be evaluated for metastatic disease. While the evaluation may vary by institution, it will most commonly consist of a whole body PET/CT or CT of the chest, abdomen, and pelvis.

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Board Review 3 – Case 2

Posted on March 25, 2020 by Brent Weinberg, MD

Board Review 3 – Case 2

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

This case shows a nodular multifocal mass along the walls of the ventricles. It is relatively low intensity on T2, hyperintense on DWI, and enhances avidly with a nodular solid pattern.

The diagnosis is: CNS lymphoma

Primary CNS lymphoma is a B-cell malignancy with relatively low incidence but overall poor outcomes. It is more common in immunocompromised or HIV patients. The most common locations are in periventricular white matter, the basal ganglia, and the corpus callosum. Solid nodular enhancement, T2 hypointensity, and low ADC values are characteristic. In fact, lower ADC values are associated with a poorer prognosis.

HIV and immunocompromised patients are more likely to have variable enhancement patterns, such as rim enhancement with central necrosis.

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Board Review 3 – Case 1

Posted on March 23, 2020 by Brent Weinberg, MD

Board Review 3 – Case 1

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

This case shows a minimally enhancing mass along the anterior part of the septum pellucidum. This patient also has hydrocephalus which may be contributing to the symptoms.

The diagnosis is: subependymoma

Masses in the ventricles and along the septum pellucidum have a broad differential diagnosis, but in this case subependymoma is the best fit because it is a relatively indolent appearing, minimally enhancing mass.

The other possibilities include:

ependymoma – usually has more avid enhancement
central neurocytoma – also usually has more enhancement
subependymal giant cell tumor (SEGT) – possible, but more likely in a patient with tuberous sclerosis
choroid plexus tumor – more commonly enhances avidly
hemangioblastoma – often will have flow voids
metastatic disease – also more avid enhancement

If you see a minimally enhancing ependymal/subependymal tumor, think about subependymoma.

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Neuroradiology physics review – 2 – Magnetic Resonance Imaging

Posted on January 18, 2020 by Brent Weinberg, MD

Neuroradiology physics review – 2 – Magnetic Resonance Imaging

It’s important for the neuroradiologist to have a basic grasp of physics, particularly in the ways that it may affect image quality. In this video, Dr. Michael Hoch goes through a series of 13 MRI cases on physics. Each case is followed by one or more multiple choice questions about that physics principle.

There are a number of ways that physics principles affect MR images, causing various types of suboptimal images, such as:

metallic artifacts – areas of signal loss around susceptibility created by metal
fat suppression artifacts – areas where fat is incompletely saturated, particularly at the edge of images or adjacent to metal
aliasing – where one part of the image is incorrectly mapped to another area due to improper field of view
staircase – motion between slices leading to step offs in reconstructed images
chemical shift artifact – when a substance such as fat has a different resonance frequency and maps elsewhere into an image
zipper/spike artifact – when an external source of frequency noise is mapped into the image domain

Other key principles discussed include:

how artifacts may help you make a diagnosis
differences in how artifacts may appear on different types of images
how to change sequences to mitigate artifact

The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who would like to review radiology physics. This may be particularly useful when preparing for the American Board of Radiology (ABR) core and certifying exams.

Check out this video and additional content on https://www.learnneuroradiology.com

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Neuroradiology physics review – 1 – Computed Tomography

Posted on October 2, 2019January 18, 2020 by Michael Hoch, MD

Neuroradiology physics review – 1 – Computed Tomography

It’s important for the neuroradiologist to have a basic grasp of physics, particularly in the ways that it may affect image quality. In this video, Dr. Michael Hoch goes through a series of 12 CT cases on physics. Each case is followed by multiple choice questions about that physics principle.

There are a number of ways that physics principles affect images, causing various types of suboptimal images, such as:

partial volume averaging – when an object only takes up part of a voxel and the resulting output
patient motion – when patient moves during imaging, degrading image quality and causing image blurring
streak artifact – when high density material adversely affects CT reconstruction, causing lines across an image
ring artifact – when a detector fails and causes rings through the image
contrast staining – when breakdown of the blood brain barrier allows leakage of contrast into the brain

Other key principles discussed include:

pitch
computed tomography dose index (CTDI)
dose length product (DLP)
pre- and post-patient collimation
image filtration

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Neuroradiology Review – Brain Gyral Anatomy

Posted on July 22, 2019July 18, 2019 by Brent Weinberg, MD

Neuroradiology Review – Brain Gyral Anatomy

In this video, we review gyral anatomy of the brain for some of the more common gyri, including the frontal lobe, temporal lobe, and midline/paramedian gyri.

The ABR board exams, both core and certifying exams, contain some basic anatomy and all of the structures here are fair game. You should be able to pick them out of a list of options as well as put an arrow on them if necessary.

This is the final video of board review 2. Tune in for more videos later!

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Board Review 2 – Case 19

Posted on July 18, 2019July 18, 2019 by Brent Weinberg, MD

Board Review 2 – Case 19

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.

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