1.5 Medical Imaging: Head and CNS Flashcards
X-Ray imaging has limited utility in neuroimaging of the head. In what cases might it be used?
- Ventricular shunts
- Skull fractures
- Bony lesions (e.g. Myeloma)
What are the standard X-ray projections used in neuroimaging? What are some of the less common ones?
Standard: AP and lateral
Specialised: Waters (chin up, like drinking water), and Townes (chin down)
What is the most common form of neuroimaging used with the skull? Within this, which is the most common technique used?
CT — most commonly, non-contrast CT
What is the reasoning behind a post contrast CT scan of the head?
- Contrast is injected intravenously
- If BBB has altered permeability, then there will be abnormal contrast enhancement
What are common indications for a post contrast CT of the head?
Intracranial neoplasm or infection
What is the difference between a CT angiogram and a regular, post-contrast CT scan?
CT angiogram is timed so that the contrast will be in specific blood vessels of interest (e.g. arteries in brain)
What are some indications for CT angiogram of the brain?
- Stroke/TIA
- Aneurysms
What conditions might indicate a CT venogram of the brain?
- Dural venous sinus thrombosis
- Arterio-venous malformations
Is MRI typically used as a first line investigation in head neuroimaging? What are some indications for MRI in this case?
- No; it is usually second line in response to abnormal CT findings
- Used for identification of acute stroke, and tumor characterisation
What midline structure separates the two hemispheres of the brain?
Falx cerebri
What is the tentorium cerebelli (in a real sense)?
An infolding of the dura mater between the occipital lobes and the cerebellum (“roof of cerebellum”)
What do intra axial and extra axial mean in neuro?
Intra: within brain parenchyma
Extra: outside brain parenchyma
