Neuroimaging Flashcards
Neuroimaging techniques
Plain x-rays
Computed tomography (CT)
Magnetic resonance imaging (MRI)
Cerebral angiography
Myelography
Nuclear medicine
1 CT scan gives a dose of radiation equivalent to how many chest x-rays
100
Disadvantages of CT
Dose of radiation
Limited anatomical detail- acquired in axial plane, volume data
May require iodinated contrast media - potential for allergic reaction
Advantages of CT
Better than MRI for demonstrating bone and calcification (craniopharyngioma/meningioma)
Seconds
Advantages of MRI
No ionising radiation
Multiple planes possible
Excellent anatomical detail
Disadvantages of MRI
Contrast injection may be required
Strong magnetic field- in some patients MRI is contraindicated
Noisy and claustrophobic
Longer scan times than CT
Contraindications for MRI
Pacemaker
Neuro stimulator
Metallic implant
No loose metal objects eg iron, steel and other ferrous materials, keys, scissors, credit cards, watches
Cerebral angiography
procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the brain
uses a catheter, x-ray imaging guidance and an injection of contrast material to examine blood vessels in the brain for abnormalities such as aneurysms and disease such as atherosclerosis (plaque)
Myelography
diagnostic imaging test generally done by a radiologist. It uses a contrast dye and X-rays or computed tomography (CT) to look for problems in the spinal canal.
What part of the body does Myelography look at
Spinal canal
Nuclear medicine- brain perfusion scan
brain perfusion scan is a nuclear medicine test that looks at the blood flow to different areas of your brain. It can be used to help in the diagnosis of various conditions including dementia, stroke, ischaemia and in some kinds of epilepsy.
Uses a radio tracer
CSF on T1 and T2 MRI scans
On T1 CSF is bright whereas it is dark on T2.
CSF on a T1 MRI
White
CSF on a T2 MRI
Dark
Colour FA maps - intensity
FA value
Brighter - more anisotropic
