Term
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Definition
| dense structures appear more white, air and water appear black |
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Term
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Definition
not performed in 1st world countries
ventricles are filled with air to make them easy to visualize on x-ray |
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Term
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Definition
posterioanterior
lateral
caldwell
townes
base
stenvers
rheese
waters |
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Term
| Uses of X-ray in neuroimaging |
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Definition
Trauma: fractures, localization of foreign bodies, detection of pneumocephalus
Evaluation of masses: displacement of calcifications, observation of abnormal calcifications, erosion of bone
Evaluation of calvarial disease: localized lesions, metastasis (bone tumor) |
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Term
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Definition
exposure to x-rays
poor visualization of soft tissues
two-dimensional representation of 3D object |
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Term
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Definition
thin section radiograph produced by creating a thin focus plane - moving the x-ray tube and film cassette siultaneously in opp. directions.
Blurs out overlying shadows |
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Term
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Definition
internal auditory canals
optic foramina
sella turcica
skull base
spine |
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Term
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Definition
used to visualize hard and soft tissues
it uses computers to reassemble the image into a series of thin 2D slices
colors are same as an X-ray |
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Term
| When is CT prefered over and MRI? |
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Definition
| when there is a head trauma patient, because the CT scan can be performed quickly |
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Term
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Definition
quantitative scale used for measuring radiodensity
lower density substances appear darker |
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Term
Houndsfield Unit for Air:
Houndsfield Unit for Water:
Houndsfield Unit for Bone: |
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Definition
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Term
| Radio-opaque material can be used: |
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Definition
with CT (because it uses x-rays) to reveal vasculature
reveals wehre the blood-brain-barrier is broken down
ie. a rapidly growing tumor may appear white bc of lack of BBB
an abcess will appear as a dark structure surrounded by a white ring |
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Term
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Definition
Trauma: intra and extracerebral hematomas, cerebral edema or contusions, skull fractures
Localization of intracranial mass lesions: tumors, intracerebral hematomas
Identification of vascular lesions: AV malformations, aneurysms
Determining Ventricular Size: hydrocephalus, pseudotumor cerebri |
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Term
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Definition
iodinated contrast material is used, X-rays are used to visualize the arteries filled with the contrast agent
a series of x-rays are rapidly shot so that the arterial, capillary, and venous phases of the brain vasculature can be visualized |
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Term
| With cerebral angiography, x-ray images are often: |
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Definition
| reversed so that arteries with contrast media appear black on light bony structures |
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Term
| How can cerebral angiography be used for information about neural structures? |
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Definition
| their known anatomical locations can be inferred via their anatomical relationship to the vasculature |
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Term
| Why is cerebral angiography being replaced with magnetic resonance angiography (MRA)? |
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Definition
although MRA is far more expensive, MRA avoids the surgical risk involved in the catheterization used to inject the contrast media
also, some patients have adverse reactions to the contrast media |
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Term
| Uses of cerebral angiography |
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Definition
| aneurysm, tumor mapping, atherosclerosis, metabolic disease, pseudoaneurysms |
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Term
| What are the negatives about cerebral angiography? |
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Definition
exposure to x-rays
surgical risk
adverse reaction to contrast medium
2D representation 3D object |
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Term
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Definition
performed to image the spinal cord and nerve roots
lumbar or lateral cervical puncture to subarachnoid space, iodinated agent is injected
images are recorded on x-ray film |
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Term
|
Definition
determination of spinal cord lesion
evaluation of relationship between spinal canal and bony spine
diagnosis of herniated disk |
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Term
| Magnetic Resonance Imaging |
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Definition
a powerful magnetic field and radiowaves are used to image tissue
atoms will align their anatomic nuclei with the field, magnetic resonance energy is released when the aligned nuclei are perturbed |
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Term
| In a T1 weighted MR image, __ appears dark and ___ is white. The CNS white matter is __ gray matter. |
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Definition
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Term
| In a T2 weighted MR image, ____ is dark and ___ is white. Flowing blood appears ___. CNS white matter appears ___ than gray matter. |
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Definition
dense bone and air
CSF and fat
dark
darker |
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Term
| The best way to tell if you have a T1 or T2 weighted image is to examine ___ or ___. If they are white, then the image is ____. |
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Definition
ventricles
globes of the eye
T2 weighted |
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Term
| Typically ___ is used to locate and discribe pathology, while ____ is used to display the normal anatomy of white vs. gray matter. |
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Definition
T2 weighted image
T1 weighted image |
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Term
| ___ images are restricted to the axial plane, but ___ images can be viewed from any plane (axially, coronally, or sagitally). |
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Definition
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Term
| Coronal MRI scans are viewed as though you are looking at the patient: |
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Definition
| in the face, and the slices are from an anterior to a posterior plane |
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Term
| Axial scans are viewed as though you are : |
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Definition
at the patients feet looking toward their head, while the patient lays on their back in the machiene
these scans show the cerebral hemispheres from ventral to dorsal |
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Term
| In both coronal and axial views the patients side is ___ the observers side. |
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Definition
opposite
(the patients left side is to the observers right) |
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Term
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Definition
contrast material can be used
gadolinium can be used to enhance vasculature and show breakdown of the BBB around tumors or abscesses |
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Term
| What devices are safe to use in an MRI? |
|
Definition
joint prosthesis
aortic aneurysm clips
bowel staples
- all after 8 wks |
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Term
| Medical devices which cannot be scanned in an MRI are: |
|
Definition
many cerebral aneurysm clips
pacemakers
epicardial pacing wires
some cochlear implants
most endovascular shunts |
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Term
Color on X-ray:
1) air
2) CSF
3) fat
4) blood
5) brain
6) bone |
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Definition
1. black
2. grayscale
3. grayscale
4. grayscale
5. grayscale
6. white |
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Term
Color on CT:
1) air
2) CSF
3) fat
4) blood
5) brain
6) bone |
|
Definition
1. black
2. black
3. black
4. lighter gray
5. darker gray
6. white |
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Term
Color on T1 MRI:
1) CSF
2) Fat
3) blood
4) brain
5) bone |
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Definition
1. dark gray/black
2. white
3. grayscale
4. white matter lighter
5. dark gray/black |
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Term
Color on T2 MRI:
1) air
2) CSF
3) fat
4) blood
5) brain
6) bone |
|
Definition
1. dark gray/black
2. white
3. white
4. dark (flowing) / white (MRA)
5. gray matter lighter
6. dark gray/black |
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Term
|
Definition
the most powerful magnets are used to examine areas of the CNS that are metabolically active during a particular assigned task
computer adjusted so that there is a difference between oxygenated and deoxygenated hemoglobin |
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Term
| In a fMRI, the metabolically active region of the CNS will have: |
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Definition
| increased blood flow with more oxygen extracted from the hemoglobin |
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Term
| Positron Emission Tomography (PET) |
|
Definition
a positively charged electron is produced and incorporated into pharmaceuticals
the pharmaceuticals are injected intravenously and give off gamma rays as they decay
the gamma rays are detected with a scanner that portray the distribution of the radionuclide through the brain |
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Term
| PET is most commonly used to display: |
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Definition
images of local metabolic rate for glucose throughout the brain
can also be used for evaluating cerebral blood flow, oxygen metabolism, and neurotransmitter receptor density |
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Term
| PET is used to detect and diagnose: |
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Definition
detect tumors and epileptic foci in the brain
dianose degenerative conditions (Alzheimers) |
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Term
| Single Photon Emission Computed Tomography (SPECT) |
|
Definition
similar to PET, but provides less detail, and the available nuclides are of less biological interest
it is however, less expensive and more widely available than PET |
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