Extravasation

Extravasation is the accidental administration of intravenously infused medications into the extravascular space around the infusion site, either by leakage due to brittle veins, previous venipuncture or mispositioned needles or IV catheters.

Infiltration, the result of an extravasation, is the diffusion or accumulation of substance not normal to it in amounts in excess of the norm.

IV infusion should be free flowing. The arm with the infusion should not begin to swell, get red (erythemia), get hot and the patient should not notice any pain or burning. It is best to assure good access with saline prior to injecting radioactive materials. Should you notice any problems with the injection stop immediately. Keep in mind that often the volume of radiopharmacuetical dose are small and a dose may be infiltrated before you can react.

With scans such as a bone scan, the extravasation of a dose may not be critical to the scan. However the  extravasation of labeled white blood cells, PET doses, any study requiring dynamic acquisition such as renal scans may result in the patient having to return for a repeat study. Take care when injecting.

Note the increased uptake of radiopharmaceutical (TC MDP) in the left hand, site of injection.

Additional views of the hand in the palmar and lateral views demonstrates increased uptake in the tissue of the left hand.

PET scan with extravasation of F18FDG in the right upper arm. In the case of PET imaging the infiltration of the dose results in invalid standard uptake value (SUV) which is determined by the exact patient dose (Pre-calibration - post-calibration) and the patient weight. If the patient dose is made inaccurate by the infiltrated dose the SUV becomes invlaid. The scan however may still be diagnostic if enough of the radiopharmaceutical has been properly delivered. The small dot of activity in the right shoulder may represent a lymph node due to the infiltration.

This patient was re-scanned with the area of extravasation out of the field of view and determined to be of diagnostic value.

Infiltrated dose of TcMDP on this bone scan shows the radiopharmaceutical tracking up the left arm with a visible lymph node in the left axilla. Not all injections are going to be perfect. If the dose is infiltrated it can be covered with lead to attenuate the accumulated dose or the arm can be moved from the image. This will provide better count statistics from the image.