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Cases in Radiology: Episode 1 (neuroradiology, CT, MRI)

Cases in Radiology: Episode 1 (neuroradiology, CT, MRI)

hello welcome to this cases in
radiology episode. I’m doctor andrew dixon from and
today’s case is a neuroradiology case which is of intermediate difficultly. this is a case of a 40-year-old
male who presented with his first episode of seizure to the emergency
department. he had a non contrast CT brian which
we’re looking through here and the abnormality seen on this non contrast CT was this subtle are of hypoattenuation within the left
superior frontal gyrus. the patient went on to have a post
contrast study and as you can see within this area there is a ring enhancing lesion measuring around 1.5 to 2
centimeters in diameter. The differential diagnosis at the stage is
quite broad for a solitary ring enhancing lesion within the brain. the mnemonic MAGIC DR is often used; M standing form metastasis, A for abscess, G for glioma such as GBM, I
for infarction particularly sub-acute infarcts, C for cerebral contusion,
D for demyelination and R for radiation necrosis. This patient of
course doesn’t have a history of radiation exposure and so that would be discounted in this case. The patient then went on to have an MRI
study and you can see on there T2 weighted images that the left superior frontal lesion is T2 hyperintense centrally with some surrounding T2 hyperintensity within the brain parenchyma.
The cortex appears relatively spared. Also within the brain you can see
other T2 white matter hyperintensities scattered particularly throughout the
corona radiata and centrum semiovale in a
periventricular distribution. This is better appreciated
on the FLAIR sequence where the central T2 hyperintensity within the lesion suppresses. some surrounding white matter hyperintensity. And multiple T2 white matter hyperintensities in a periventricular distribution are seen. On the sagittal FLAIR imaging, you can agin see the regional of the mass in a subcortical location within the white matter. And as we come out to the side, we can see the white matter plaques which are arranged perpendicular to the ventricles. When you give contrast the lesion enhances in a
ring enhancing fashion with some nodules of more prominent
enhancement. When we look on the coronal images we can see that the lesion has an incomplete ring of enhancement or open ring enhancement sign. The
portion of the lesion on the gray matter aspect is no enhancing whereas the white matter aspect has an enhancing rim. On the diffusion sequences there was no diffusion restriction. so putting the two MRI findings together; the mass and the white matter plaques, the possibility
of multiple sclerosis with an active lesion or tumefactive lesion was raised. given that the left frontal mass like region was in non-eloquent cortex and easily accessible, the patient went on to
have a biopsy. the pathology was confirmed to be active
demyelination or tumefactive MS. The biopsies contained heavy
infiltrate of macrophages, a small number of lymphocytes and the Luxol fast blue
stain showed loss of myelination. This case demonstrates nicely the Dawson’s fingers which are
characteristic of multiple sclerosis and also demonstrates the incomplete
enhancement sign or open ring sign of active demyelination.

15 comments on “Cases in Radiology: Episode 1 (neuroradiology, CT, MRI)

  1. Excellent case and presentation, thanks for sharing. If you come across any interesting temporal bone MRI's please do share, I cannot for the love of God understand what is going on inside there. Please tell me it's not just me…

  2. Magic Dr:
    Glioma (e.g GBM)

    Demyelination (e.g multiple sclerosis)
    Radiation necrosis

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