Neurological Imaging and Neurointervention-Rangaswamy Flashcards
A characteristic X-ray is (blank) bremsstrahlung and (blank) percent characteristic x-ray
80%
20%
(Blank) xrays involve electrons going against tungsten atom, deviation due to nucleus ->loses energy, which comes out as x-ray
bremsstrahlung
(blank) xray uses a heated filament to produce an electron beam that hists a metal target (angstrom)
characteristic
• 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)
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
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
IF something is hyperechoic, what does this mean?
it is reflected back (like dense tissues)
HyPOechoic is like blood (passes right through)
What does a doppler do?
gets velocity of flowing blood
High velocity indicates stenosis
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
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
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
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
What is the most commonly used modality in neuroimaging?
MRI
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,
In an MRI, most pathologies will be bright on (blank)
T2
(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
(blank) identifies what areas using more oxygen during specific patients movement in real time (or language etc.)
Functional MRI
(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
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
Is neurointerventional radiology invasive?
no it is minimally invasive!
What are common neurointerventional surgeries?
- angioplasty
- stent placement
- thrombolysis and thrombectomy
- coiling
- embolization
How does an angioplasty work and where do you commonly put them?
- stenosed (narrowed) vessel
- place balloon and dilate it
- common in heart
What is this:
metal device places at site of stenosis
stent placement