#neurorad

[teachingrounds]

Today's case is a mass at the cerebellopontine angle (CPA) with classic features of an extra-axial tumor: CSF cleft (yellow arrow), displacement of subarachnoid vessels (blue arrow), and displacement of gray matter (red arrow). In addition, there is expansion of the subarachnoid space along the skull base anterior/lateral to the mass.

Differential diagnosis of a CPA mass in an adult is schwannoma, meningioma, ependymoma, and metastasis (note that ependymoma is intra-axial). Of these, schwannoma is by far the most common at this location (90%), and this was indeed a schwannoma.

Image credit: radiologyassistant.nl

[neurocirurgiabr]

Agenesis of the corpus callosum (СС) is one of the most frequent malformations in brain with incidence raging between 0.5 and 70 in 10,000. #Repost @oncology.imaging ・・・ #cns #neurorad #neuroradiology #neuro #neurosurgery #medschool #neurocirurgiabr #neurosurgeryblog

[teachingrounds]

This week we are discussing imaging of brain tumors in adults. MRI with and without contrast is the imaging modality of choice for brain tumors, although many tumors are initially discovered at CT performed for other purposes.

Today’s case is a 75-year-old woman who presented with right-sided weakness. CT revealed a large, heterogeneous mass centered in the left thalamus / basal ganglia. Internal hypoattenuation is compatible with necrosis, while surrounding hypoattenuation is compatible with edema. There is obstructive hydrocephalus. MRI confirmed the findings and revealed peripheral, nodular enhancement and extension across the midline and along the brain stem.

Findings are highly suggestive of high-grade glioma. Stereotactic biopsy confirmed glioblastoma, IDH wild type.

Case courtesy of Bruno Di Muzio, Radiopaedia.org, rID: 40573

[teachingrounds]

Another clue to the differential diagnosis of brain tumors is whether the lesion crosses the midline. Today's image depicts several entities that commonly cross midline: lymphoma, glioblastoma (GMB), meningioma, and radiation necrosis (tumor mimic). Metastases should also be considered (as always for any intracranial lesion in an adult).

Other tumor mimics that can cross midline are infection, hemorrhage, and demyelinating disease (e.g. MS, NMO, or ADEM).

Image credit: radiologyassistant.nl

[teachingrounds]

Determining whether a tumor is Intra-axial (arising from the brain) versus extra-axial (arising from meninges, pituitary, etc.) is important to developing a differential diagnosis.

Today’s case is a supratentorial mass. Gray matter is seen along the medial edge of the tumor (red arrow) indicating this is intra-axial. The most common supratentorial intra-axial lesion in an adult is metastasis, followed by glioma. This was a melanoma metastasis.

Side note: Differential diagnosis for this lesion if it were extra-axial would be metastasis versus meningioma.

Image credit: RadiologyAssistatnt.nl

[teachingrounds]

This is an approach to brain tumors as published on radiologyassistant.nl. Read the full article on their systematic approach here https://radiologyassistant.nl/neuroradiology/brain-tumor/systematic-approach

Cases presented through the rest of the week will focus on applying this approach to brain tumors in adults.

#TeachingRounds #Neurology #Radiology #Neurosurgery #Oncology #Neuroradiology #NeuroOncology #cancer #Neurorad #MRI

[teachingrounds]

MRI is the imaging modality of choice for imaging multiple sclerosis and is useful for initial workup and for following imaging findings in patients with known or suspected multiple sclerosis. The imaging findings are those of demyelination: lesions are T2 hyperintense, T1 iso- to hypointense, with acute demyelinating lesions demonstrating enhancement.

The key consideration under McDonald’s criteria is dissemination of classic lesions in space and time.

Dissemination in space ≥1lesion in 2 or more of the following locations: periventricular, cortical or juxtacortical, infratentorial, and spinal cord.  

Dissemination in time  A new enhancing or T2/FLAIR hyperintense lesion OR an enhancing lesion and a non-enhancing lesion seen on the same imaging study. 

Left image: Classic FLAIR hyperintense periventricular lesions, radiating upward, the so called “Dawson’s fingers.” Right image: T2-weighted imaging showing typical cervical spinal cord lesions.   Cases courtesy of A. Prof. Frank Gaillard, Radiopaedia.org, rID: 35916 and 2635

[neurocirurgiabr]

ASL CBF maps are effective in preoperative evaluation of gliomas #Repost @the_ajnr ・・・ : gliomas with a higher blood flow are more malignant, however gliomas with a lower blood flow are likely to be more aggressive » 3D Pseudocontinuous Arterial Spin-Labeling MR Imaging in the Preoperative Evaluation of Gliomas » Zeng Q. et al. AJNR, October 2017 » Read this article at www.ajnr.org. #neurorad