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64 Cards in this Set
- Front
- Back
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When does cortical gyriform enhancement occur on a contrast CT
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subacute stroke (2 weeks)
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What symptom do 80% of pt with brain tumor present with
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seizure
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What % of patients with acute stroke present with seizure
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3
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What pathology should you have in mind if a pt gets imaging after a sz
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brain mass, vascular malformation, infection
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What is the name of a primary tumor of the neuronal supporting structure
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glioma
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What are the 6 main subtypes of brain tumors
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glioma
Extra-axial: meningioma, hemangiopericytoma neurocytoma medullo PNET Mets |
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What is the name of the primary tumor arising from the brain covering
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meningioma
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What is a primary neuronal tumor
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neurocytoma
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What is a primary tumor of primitive cells of the brain
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medullo
PNET |
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What type of brain tumor predominate the glioma or neurocytoma
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glioma
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What is the overall most common tumor of the brain
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mets
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What is the first thing that you should look for if you see a brain mass
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look for an additional tumor. If there is it is most likely mets
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What the ddx for multiple lesions of the brain
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mets
abscess demylinating lesion strokes |
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What is the gold standard of imaging brain tumors
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MRI with gad
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What are the 3 "H's" of tumor related complications
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hydrocephalus
hemorrhage herniation |
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What is the likely cause of hypodensity surrounding the dilated ventricles on CT
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transependymal CSF
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How do you determine if there is herniation occuring
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if the cisterns are collapsing
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Are RCC mets often hemorrhagic
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yes
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What is particularly not seen well with CT
What are the MR characteristics of GBM |
non-enhancing infiltrating tumors
MRI T1: hypo to isointense mass within white matter central heterogenous signal (necrosis, intratumoural hemorrhage) T1 + GAD: enhancement is variable, typically peripheral and irregular T2 / FLAIR: hyper intense surrounded by vasogenic oedema flow voids occasionally seen DWI : No diffusion restriction, however, lower measured ADC than low grade gliomas. |
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What are 4 characteristics of glioblastoma multiforme
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necrotic area/hemorrhagic area, infiltrative, bright on T2 or flair, enhancing with higher grade glioblastoma
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Does a pilocytic astrocytoma enhance
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yes
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Does a craniopharyngioma enhance
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it has a thin rim of enhancment
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What type of tumors are well circumscribed, well defined
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extra-axial tumors (mc meningioma)
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If the tumor is not as bright as CSF on T2 imaging what does that mean
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it is a more cellular tumor
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What are some examples of cellular tumors
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meningioma
PNET lymphoma |
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What does PNET stand for
What are the MR characteristics of lymphoma |
primitive neuroectodermal tumors
T1 : typically hypointense to white matter T1+ (GAD) : typical high-grade tumours show strong homogenous enhancement while low grade tumours have absent to moderate enhancement T2 : hyperintense 15 - 42% more frequent in low-grade tumurs white matter hyperintensities (leukoencephalopathy) : rare |
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What type of tumors has a combination of a cyst and a nodule with minimal surrounding edema
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pilocytic astrocytoma (MC)
ganglioglioma pleomorphic xantho-astrocytoma hemangioblastoma (but only if in the posterior fossa) |
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Where are hemangioblastomas commonly located
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the posterior fossa
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What components of a mass are bright on T1 weighted imaging
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hemmorrhagic
lipid containing mass |
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What is the best test for calcification
What are the different types of astrocytomas |
CT
diffuse astrocytoma or low grade astrocytoma : WHO grade II (10 - 15% of astrocytomas) fibrillary astrocytoma protoplasmic astrocytoma gemistocytic astrocytoma anaplastic astrocytoma : WHO grade III (25% of astrocytomas) glioblastoma multiforme : WHO grade IV (50 - 60% of astrocytomas) Other astrocytomas that dont fall under this classification include: pilocytic astrocytoma, pilomyxoid astrocytoma subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma |
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What lesions have a thick ring of enhancement (ring-enhancing) after contrast
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MAGIC DR
Mets abscess glioblastoma infection (tb)/infarct? contustion demyelinatin radiation |
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What is the ddx for multiple lesion
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demyelinating
abscess mets emboli-multible strokes |
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What are the three most important MR sequences to evaluate when looking for a brain mass
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pre and post contrast T1
then DWI |
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What is the most common and most aggressive glioma
What are the findings on CT |
GBM
irregular thick margins : iso to slightly hyper attenuating (high cellularity) irregular hypodense centre representing necrosis marked mass effect surrounding vasogenic oedema haemorrhage occasionally seen calcification is uncommon intense irregular, heterogenous enhancement of the margins is almost always present |
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What is the predominate location of GBM
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supratentorial WM
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What are the MR characteristics of GBM (T1, T1 +GAD, T2, GRE, DWI)
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T1: hypo to isointense mass within white matter
central heterogenous signal (necrosis, intratumoural hemorrhage) T1 + gad: enhancement is variable, typically peripheral and irregular T2 / FLAIR: hyperintense surrounded by vasogenic edema flow voids occasionally seen GE (gradient echo) / SWI : susceptability artifact on T2* from blood products (or occasionally calcification) DWI : No diffusion restriction, however, lower measured ADC than low grade gliomas. |
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Are GBMs vascular
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yes
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Are GBMs infiltrative
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yes
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What is the WHO grade of GBMs
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4
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Are GBM often difficult to diagnose because of there multiple ways of presentation
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yes, sometimes no central necrosis, no enhancement, well circumscribed (doesnt look like infiltrative tumor),
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What % of GBM do not enhance
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1
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What is a less malignant version of a GBM
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fibillary astrocytoma
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What is the typical age group for GBM and fibrillary astrocytoma
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GBM is an older age group
Fibrillary astrocytoma is a younger age group |
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Can a fibrillary astrocytoma progress to a high grade malignancy
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yes
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What happens to the enhancement characteristics of a fibrillary astrocytoma as there malignancy increases
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the ability of the fibrillary astrocytoma to enchance increases as it becomes more malignant
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What is the grade of a juvenile pilocytic astrocytoma
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grade 1
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What is the population that is affected by juvenile astroctyoma
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children
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What are the characteristics of a juvenile pilocytic astrocytoma
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well circumscribed with cyst and mural nodule, minimal enhancement and minimal surrounding edema
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What is the ddx for a tumor with a mural nodule with cyst with minimal enhancement
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jpa
pxa ganglioglioma hemangioblastoma (posterior fossa and has more edema) |
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What is PXA
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pleomorphic xanthoastrocytoma
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Is pxa rare
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yes
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Is pxa low grade
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yes
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What group tends to get PXA
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children and young adults
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Where do PXA MC occur
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the temporal lobe
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What is the Characteristics of PXA
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cyst with nodule and minimal to mild edema
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What has a better prognosis an oligodendroglioma or an astrocytoma
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oligodendroglioma
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What area of the brain do oligodendrogliomas commonly occur
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the frontal lobe
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What age group do oligodendrogliomas typically occur
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younger pts
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Do oligodendrogliomas typically involve the cortex
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yes
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How do oligodendrogliomas appear on imaging
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aggressive, expansile, invasive, large, cortically based, calcification
Note: these are usually relatively benign and look bad but can have an anaplatic component |
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What is the ddx for tumors with calcification
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oligodendroglioma
ependymoma craniopharyngioma choroid plexus tumor meningioma |
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What type of tumor is an ependymoma
Are ependymal cells a type of glial cells What is the function of an ependymal cell |
an extra-axial and arises from outside the brain (ependymal cells)
yes, they are 1 of the 4 glial cells create and secrete CSF (the choriod plexus is made up of modified ependymal cells), and help circulate the csf with their villi |
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What is the 3rd mc pediatric brain tumor
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ependymoma
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Where do 60% of ependymomas occur
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infratentorial (around 4th ventricle)
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