GDD secondary to small volume GBCA administration techniques: How can this happen?
There are a number of individuals who have spoken to me about GDD developing in circumstances where small volume GBCA administration has occurred. Examples are GBCA-injected MR arthrography (administering GBCA into a joint space to look for cartilage injury or joint capsule disruption), and interstitial injection of GBCA due to a blown venous injection. MR arthrography is intentional, and interstitial injection unintentional.
MR arthrography typically may inject 1- 2 ml of GBCA (compared to standard iv which is 10-15 ml of GBCA), and interstitial injections often may be caught at 5 ml of GBCA injected.
It seems somehow improbably that so little GBCA can cause GDD, that may be as severe as GDD following 15 ml, and even multiples of 15 ml.
How can this be explained?
In some ways this can be thought of in a similar fashion as vaccine injections, which are small volume and injected subcutaneously or intradermal. They are contained in that location so the immune system has time to develop a reaction to it.
The GBCA contrast in these localized injections into contained spaces do not have ready access to the vascular system to get eliminated (somewhat) rapidly. GBCA stays in the joint space and interstitial space for a much longer duration of time than vascular injection, hence the immune system has time to develop a strong reaction. Elimination in contained injections depends on a combination of diffusion out of the location, lymphatic drainage, and capillary-venous elimination, which takes time.
The longer intracorporeal dwell time for contained injections explains why even small volumes can cause GDD.
It is not clear at this time whether chelation is effective in the setting where very little GBCA is likely in the body, or whether the primary treatment will be mitigating the auto-immune type reaction.
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Richard Semelka, MD. Consulting