INDIUM SCANNING Flashcards
How do you complete the test?
Take blood, separate WBCs, label them with 111 Indium, Re-inject in patient, scan patient 4 to 24 hrs later. (up to 72 hrs)
why do WBCs act as a good marker for disease conditions?
WBC’s normally travel to inflamed/infected areas (don’t have any innate bone afnity)
Indium has high sensitivity (90-100%) & specificity (80%) in diabetic foot ulcers, T/F?
T
indium half life?
2.8 days
congruent scan equals?
negative for infection
incongruent scan equals?
POSITIVE for infection (OM)
Labeled WBC’s DO or DO NOT usually accumulate at sites of increased bone mineral turnover when patient doesn’t have an infection?
do not
You can’t distinguish rapidly progressing DNOAP (charcot) from OM with MRI or
combined Tc/In scans,
T/F?
true
problems with In-WBC scans?
Can’t distinguish non-infected DNOAP from OM.
Indium will localize at non-infected fracture sites (leading to false +’s)
Not bone seeking
If wounds leak/drain the tracer will be found in the dressings – (complicating imaging)
How do you determine if the problem is in the BONE or SOFT
TISSUE?
In most cases, cellulitis vs. OM can be discerned by Tc-MDP & In-WBC overlap scans.
**Indium provides what kind of mapping?
functional
**Tc provides what kind of mapping?
structural
In charcot joint disease, WBC uptake within bone doesn’t automatically = OM; so what do you use?
Use 4 & 24 hrs scans to determine if a rapidly progressive DNOAP is infected.
this is why we need the marrow scan
What can cause an increase in WBC uptake, leading to False (+) “Fake-outs”?
Fracture/periosteal callus, soft-tissue ossification, increased bone remodeling, etc.
but,
Active RA, Charcot, — These all cause re-Activation of marrow.
indium has an affinity too?
RED marrow
