CNS procedures Flashcards
Where do you do a spinal tap
BELOW L2
L4-5 is 1st choice
low pressure tap
<7cm
hypoproduction
distal to occlusion from tumor
spinal fluid leak (after craniotomy or large bore needle)
high pressure
high pressure >25 hyperproduction proximal to production malabs of fluid obesity (pseudotumor cerebri)
xanthochromic
just plasma from clotted or old blood d/t CNS bleed
What indicates infection in CSF analysis
turbid fluid with WBC>200 or >400 rbc(AI)
high CSF protein
degenerative disease traumatic tap (from RBCs)
Epidural space
is a potential space that does not contain fluid or blood
only access to the nerve roots
catheters are placed first to open the space w/ air
just numbing the nerve roots
Negative EEG in a case of suspected seizure
DOES NOT RULE anything out
Role of X-ray
cheapest way to assess acute neurological damage, especially in cases of trauma.
check out the C-spine
Spiral CT
continuous running time, dont stop b/w slices
Much faster than regular
but its hotter and has more rad
Why CT useful
1) Hemorrhages**(no contrast needed)
2) spinal fx
3) Kidney stones
Need contrast:
4) Abscess
5) Tumor
PET scan
inject radiolabled FDG (glucose)
great for detecting CA (use sugar 2x the rate as normal cells)
always concentrated in bladder, kidney, brain
T2 image
Water, edema, tumor, infarct (CSF) is bright)
Calcifications, fibrous tissue, maramagnetic stuff (Fe, Hb.. is dark)
FLAIR
is T2 w/ spinal fluid brightness blocked out, so you can see bad fluid that should not be there
EDEMA and GLIOSIS are hyperintense
T1
wtaer (infarct, CSF, inflammation) is dark
Fat, and hemorrhage is dark
