Neurological Imaging and Neurointervention-Rangaswamy Flashcards by Danielle Hayes

A characteristic X-ray is (blank) bremsstrahlung and (blank) percent characteristic x-ray

80%

20%

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(Blank) xrays involve electrons going against tungsten atom, deviation due to nucleus ->loses energy, which comes out as x-ray

bremsstrahlung

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(blank) xray uses a heated filament to produce an electron beam that hists a metal target (angstrom)

characteristic

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• X-ray beam hits body and penetrates tissues
o (blank) blocks the beam, which is what produces image
o Bone appears bright
o Information limited due to lack of 3-D

Calcium (bone)

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What is this:
inject iron dye that goes through blood vessels; uses same x-ray technology
o Iron blocks x-ray beam allowing us to view blood vessels
 Can exam vessels in brain masses
 ID aneurysms

catheter angiography

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What is the physics behind an Ultrasound?

What color is fluid in an ultrasound?

send a sound signal, signal hits object and returns to localize object.
fluid is dark

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IF something is hyperechoic, what does this mean?

it is reflected back (like dense tissues)

HyPOechoic is like blood (passes right through)

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What does a doppler do?

gets velocity of flowing blood

High velocity indicates stenosis

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What is the difference between angiogram and CT w/ contrast?

CT angiogram – instead of going into artery to inject dye we can just inject into vein
CT w/ contrast – ingestion of contrast; infiltrates everywhere, not just blood vessels

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What is the physics behind a CT scan?

Rotational x-ray source inside ring of detectors
Possible to get whole body scan in 1-2 minutes
Hyperdensities – bone; white
Hypodensities – dark; fluid

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What is this:
uses gamma rays sent from outside
Make radioisotopes and combine with some other elements
• Ex. Can mix with WBCs and inject back into patient
o Wherever WBCs go you get signal

nuclear medicine

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What is this:
combined fluid isotope with deoxy-glucose (reaches every part of body); inject into body
• Anywhere with high metabolism (tumor) lights up
• Can detect hypometabolism

PET scan

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What is the most commonly used modality in neuroimaging?

MRI

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How does an MRI work?
How will blood and water present on a T1 image?
T2?

uses inherent signas in the body by detecting the rotation of hydrogen atoms within our body.

T1: water-> dark, Hemorrhage-> bright

T2: Water/tumor-> bright,

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In an MRI, most pathologies will be bright on (blank)

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(blank) can get info on individual molecules in tumors, diagnosis can be based on this info. (blank) indicates high turnover. (blank) is only seen in neurons

spectroscopy
choline
NAA

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(blank) identifies what areas using more oxygen during specific patients movement in real time (or language etc.)

Functional MRI

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(blank) is a 3D modeling technique used to visually represent neural tracts using data collected by diffusion tensor imaging (DTI). It uses special techniques of magnetic resonance imaging (MRI), and computer-based image analysis.

diffusion tractography

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What is this:
practioners insert a catheter into groin and thread it through vessels to probems site. Physician can deliver meds or ustilize medical devices to accomplish treatment

Neurointerventional radiology

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Is neurointerventional radiology invasive?

no it is minimally invasive!

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What are common neurointerventional surgeries?

angioplasty
stent placement
thrombolysis and thrombectomy
coiling
embolization

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How does an angioplasty work and where do you commonly put them?

stenosed (narrowed) vessel
place balloon and dilate it
common in heart

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What is this:

metal device places at site of stenosis

stent placement

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What is an aneurysm?

Why are they worrisome?

bulges in vessels

-high potential for bleed and if in the brain can cause increased ICP

Do people survive aneurysms often?

no, 50% of patients never make it to hospital and there is a high chance of rebleed w/in a month

What is coiling?

fills weak areas that have aneurysms.

What is thrombolysis and thrombectomy?

blood clot lysis and surgical removal of clots too large to lyse

What are 2 image-guided treatments?

- endovascular treatments | - percutaneous image-guided treatments

What are the principles of imaging?

- Anatomy - Pathology - Clinical info - Look for altered anatomy and signal changes - Secondary effects - Primary cause (differential diagnosis, diagnosis)

What are you looking for with anatomy?

-symmetry, morphology (blood vessels, ventricles, buds, masses)

What are you looking for with altered anatomy and signal changes?

o Radiodense vs. radiolucent (x-ray, CT) o Hyperechoic vs. hypoechoic (US) o Increased activity (nuclear medicine) o Hyperintense vs. hypointense (MRI)

Imaging is mainly used as a (blank) modality. It is used to mainly do what? Imaging is also used to do what?

screening rule out uncommon diseases confirm clinical diagnosis and further characterization (e.g acute stroke, advanced tumor imaging)

What is this: | neurologic deficit that lasts more than 24 hours.

acute ischemic stroke

A major stroke is defined as a neurological deficit with the NIH stroke scale score of greater than or equal to (blank) and sustained for longer than (blank) days

4 | 7

In acute ischemic stroke what imaging should you get to see immediate findings? What should you use to look for occluded vessels? What imaging is less accurate but can be used to look at clots or hemmorhage and what is its downside?

MRI angiogram CT scan-> need to wait 24 hours to see ischemic stroke

When someone has head trauma, what is the first thing you do and why?

you get a head CT so you can check for hemmorhage

What is the difference between ischemia and infarct?

ischemia-> syndrome, but brain is still viable (loss of function, but potential to treat and reverse) infarct-> brain tissue is dead

What is the sign that is subtle and an early sign of infarct?

insular ribbon sign

If you are doing a CT and you see a hyperdense artery what does this mean? What does a hemorrhage look like?

fresh clot and it will be bright (vessels shouldnt be seen) | Bright also

What is the order of imaging you should do with someone that has a stroke?

CT-> make sure no hemmorhage CT angiogram-> check vessels MRI-> check for infarct

What is this: bleeding into subarachnoid space (area between arachnoid membrane and pia mater surrounding the brain, space that contains blood vessels)

acute subarachnoid hemorrhage

What is the approach to treating a subarachnoid hemorrhage?

Preventing further bleeding because primary bleed has already stopped

An aneurysm is a dilation of any vascular structure, usually located where?

at the base of the brain (not actually within the brain)

What imaging should you use for an acute subarachnoid hemorrhage? What is sad about these bleeds?

1st: non-contrast CT scan 2nd : CTA (identify bulge location) -> very complicated surgery (30% mortality)

What is a bleed within the parenchyma?

an acute intraparenchymal hemorrhage

What are intraparenchymal hemorrhages due to? How do you treat this?

hypertension or vascular malformation | - surgery

Why will you use a MRI for acute intraparenchymal hemorrhages?

to look for AV malformations

How do you treat an acute intraparenchymal hemorrhage?

ONYX embolization | very difficult and it is a 6 month process

Why will a hemorrhage appear bright on a CT scan?

hemoglobin

What is most sensitive for stroke?

diffusion weight sequence

What will a subdural hemorrhage appear like on a CT scan?

crescent shaped

What will a epidural hemorrhage appear like on a CT scan?

usually biconvex shaped

When you have a brain tumor, what should you use to look at it? What four things should you look for?

Contrast CT (look at meninges) - surrounding edema - necrosis - enhancement - hemorrhage

If the BBB is intact, what tumor grade is it?

What grade is a GBM?

grade 4 | enhancement, necrosis and edema

What is this: • Looks similar to GBM • Look at capsule; well-defined lesion • Diffusion weight sequence – bright; no movement

brain abscess

(blank) is used to make certain structures appear brighter on MRI (i.e. contrast agent)

Gadolinium

o Gray matter is brighter than white matter b/c gray matter is more (blank)

dense

What is this:  Dawson finger morphology • Along the ventricles  Demyelinating disorder