Lecture 2 a and b Flashcards by Maddey Wilson

Indications for Imaging

Generally, imaging is essential for:

the localization of a lesion (all)
Determination of a diagnosis

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Indications for Imaging

More specifically, neuro imaging aids in ruling in/out:

Skull or vertebral fractures
Acute or chronic infarcts (hemorrage, ischemia)
Blockage in blood vessels
Infections
tumors or masses

other uses of imaging include: research, clinical trials, post-mortem diagnostics, assesment of risk factors

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What plane is this picture?
And what is the standard orientation?

Frontal/Coronal
standard Right/Left orientation

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What plane is this picture?
And what is the standard orientation?

Plane: Saggittal/Longitudinal
standard orientation anterior/posterior

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What plane is this picture?
And what is the standard orientation?

Plane: transverse/axial
standard is right/left orientation

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X-ray is what?

A non-invasive visualization of internal structure.

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X-ray Pros?

Simple, quick, cheep
Helpful in detecting presence of fractures, calcificaiton, lesions, tumors

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Cons of X-ray?

Limited capability to visualize soft tissues
Exposes patient to radiation

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Computed Tomography CT?

X-ray based
Cross sections = 3D image

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Pros of CT?

quick
relatively inexpensive

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Cons of CT?

Difficult to see posterior fossa and spine due to bone.
Exposes patient to radiation

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Ct is good for what?

Good sensititivity, porr specificity for hemorrhagic stroke
Often need follow up for more information

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On a CT gray matter shows up as what color?

Light grey

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On CT white matter shows up as what color?

Dark grey

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On CT air shows up as what color?

Black

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On CT fat shows up as what color?

Dark grey/black

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On CT bone shows up as what color?

white

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On CT liquid shows up as what color?

Very dark/ black

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CT Angiogram

Used to visualize arties and viens
Used to look for blockages stenosis, aneurysm, or disecting/tearing of walls.
Reuies injection of contrast material.

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Which artery is occluded?

Internal Carotid Artery
ICA

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MRI is what?

Non-invasive method using magnets to produce a 3D image/

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Pros of MRI

Higher resolution especially for ischemis and areas of soft tissue, posteiror fossa, spinal cord
No radiation exposure

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Cons of MRI

Takes time
Patient needs to remain still
May be contraindicated if patient has pacemaker or metal implants
Can be expensive

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MRI T1 gray matter is what color?

dark ish grey

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MRI T2 gray matter is what color?

Light grey

MRI T1 white matter is what color?

light grey

MRI T2 white matter is what color?

Dark grey

On MRI T1 air is what color?

Black

On MRI T2 air is what color?

Black

On MRI T1 fat is what color?

white

On MRI T2 fat is what color?

light/ white

On MRI T1 bone is what color?

White/light grey

On MRI T2 bone is what color?

Dark grey

On MRI T1 liquid is what color?

Black dark

On MRI T2 liquid is what color?

White

MRI - Fluid Attenuated Inversion Recovery FLAIR

Simular to T2 MRI except longer exposure and relaxation time CSF signal is attenuated (appers Darker) So other abnormailites, such as hemmorrhage will be more distinct

MRI - Diffusion Weighted Image

* MRI technique with contrast added * Used to visualize areas of ischemia early after loss of blood flow (3 hours)

MRI - Diffusion Tensor Imagin DTI

MRI technque used to map the tracts of axonal white matter in the brain Often an adjunct to a regular MRI Color coding often denotes the direction the tracts are traveling - red for right-left -blue for dorsal-ventral - green for anterior-posterior

Functional MRI (fMRI)

*MRI technique that indicates where there is an increase in oxygen uptake compared to the resting state *Shows regions of increased neural activity in the brain

Magnetic Resonance Angiogram (MRA)

*MR technique used to visualize the vascular system

PROS to MRA

no radiation or contrast needed

CONS to MRA

* Increased time and cost * Patient must stay still during the procedure or images may not be clear

MR Angiogram which artery is occluded?

Middle cerebral artery MCA

CT vs MRI

Positron Emission Tomography (PET)

*Positron-emitting radioisotopes measured by a gamma-ray detector system *shows areas of cerebral blood flow, brain metabolism, and other chemical processes

PET pros

*shows typical and atypical areas of activity *low radiation risk

Cons PET

*poor resolution * many of the radioisotopes decay quickly

Tissue Type? Bilateral or Unilateral? What is 1?