Ch. 2 Neurosurgical investigations Flashcards
Describe the flow of CSF from production to absorption
Choroid plexus of lateral ventricles, Foramen of Monro, Third ventricle, Cerebral acqueduct, Fourth ventricle, Foramen of Magendie and Luschka.
Next moves to spinal subarachnoid space, through basal cisterns, over tentorial hiatus, and then bathes the cerebral hemispheres until absorbed by arachnoid villi of dural sinuses
CSF is produced by the choroid plexus at a rate of _____ mL/min.
Approximately ____ mL of CSF is produced each day.
The total CSF volume is ____.
0.4 mL/min
500 mL produced each day
140 mL total CSF volume
What is the normal CSF opening pressure in the recumbent (lying down) position?
10-15 cm CSF
Define cistern
A collection of CSF at a site where the arachnoid layer out-pouches (i.e. is separate) from the underlying pia mater.
What are three spaces where CSF can be isolated from?
Lumbar spine (Lumbar puncture)
Cisterns (Cisternal puncture)
Ventricles (Ventricular cannulation)
What is the most important contraindication to a lumbar puncture?
Clinical evidence of raised intracranial pressure (e.g. papilloedema)
*May want to get CT or MRI to r/o space-occupying lesions
The iliac crests are a fairly reliable marker of what spinal level?
When performing a lumbar puncture which direction should the needle be pointing, cranially or caudally?
L3-L4
Cranially
What is the most common complication of lumbar puncture?
Why does it occur?
What should be done to reduce the risk or alleviate the pain?
Headache
Low CSF pressure from leak through the dural hole
Instruct the patient to remain lying down and stay adequately hydrated
Electrophoresis of CSF is useful if what type of disease is suspected?
Demyelinating
What are three structures on a head CT where calcification is a normal finding?
Pineal gland, choroid plexus, basal ganglia
What is the primary contrast agent used in CT scans?
Do the following enhance?
- High grade glioma
- Low grade glioma
- Most tumors
- AVMs
- Cerebral abscess
Radioactive iodine
High-grade glioma: Yes Low-grade glioma: No Most tumors: Yes AVMs: Yes Cerebral Abscess: Yes, but only peripheral enhancement
What is digital subtraction angiography?
A type of angiography where the pre-contrast image is subtracted from the post-contrast image to obtain an image of predominantly the vasculature
What is the difference between a CT of the spine and myelography?
In myelography a water-based contrast is injected into the dural sac
In MRI, what does “magnetic susceptibility” refer to?
What type of pathologies often display this feature?
The ease by which a tissue becomes magnetized when placed in a magnetic field.
Hematoma degradation products demonstrate susceptibility from deoxyhemoglobin and hemosiderin
On a T2 weighted MRI how does CSF appear?
How do blood vessels and sinuses appear?
CSF appears white and other fluid accumulations as well
Blood vessels and sinuses appear dark because the fast moving blood is not picked up
