Neuroradiology Flashcards
What colour are structures in the brain by CT scan?
Bone - white CSF - hypointense Muscle - mid gray White matter - darker grey Grey matter - light grey Fat - dark
How can you determine if there is bleeding in the brain?
Use contrast media. It usually should not cross the blood brain barrier.
How do X-ray films work?
An anode shoots X-rays through a person onto silver bromide film. X-rays that hit dense structures such as bone are stopped. X-rays that go through hit the film and form a stable dark colour.
What are the uses of X-ray and what are the pros and cons of X-rays?
Cervical spine trauma
lumbar and thoracic spine degenerative disease
Angiography with contrast media.
X-rays are cheap, fast, easy and widely available.
They are only 2D so you need two angles, they use ionizing radiation, they have limited information.
X-rays are over used for head trauma.
What are the uses of CT-scans and what are the pros and cons of CT scans?
Fast 1-20 mins, relatively widely available, 3D formating available, intermediate cost. It is quantitative.
Cons: slower and more expensive than X-ray. Uses high dose ionizing radiaton.
Good for acuter trauma, stroke to rule out bleed, angiography with contrast media, facal trauma.
Anode provides a fan of X-rays as it and the detector rotate around the head.
What should be done within 6 hours of a stroke?
You can give Tissue plasminogen activator or clott removal. This improves the outcome however, yoive TPA if there is a haemorrhage so need to perform a CT to check.
What are the changes seen on a CT following a stroke.
Loss off defination between white and grey matter, ill defined internal capsule, hyperintense middle cerebral artery (sometimes).
Sometimes these aren’t seen early. May take 24 hours, no TPA. Can send for an MRI.
Using CT, how can you differentiate between a epidural, subdural and subarachnoid haemorhage.
Epidural - lens shape - trauma cause
Subdural - long and thin - trauma cause
Subarachnoid - hyperintense blood all over the brain. Aneurysm cause.
What are the uses of MRI and what are the pros and cons of MRI?
No ionizing radiation Excellent for brain imaging multiple modes Contrast ca be manipulated Acute ischaemia demonstrated early Tumours Agiography with or without contrast
Disadvantages: takes a long time, expensive, not widely accessible, motion sensitive, need high level of expertise,
Danger from metal.
How do you identify T1 or T2 weighted MRI?
T1: csf is dark fat is bright
T2 CFS is hyperintense fat is dark
What other types of MRI are there?
Functional MRI - ask patient to move arm and see what parts of the brain light up. Can see if a tumour will impact that area.
DTI MRI - follow axon tracts to see white matter tracts.
Can also combine them all. See tracts, functional area and MRI scan to see if cutting out a tumour will affect any area or tracts.
