What is the Importance of Gadolinium Observed in the Brain on MRI?
The short answer - it is of no value and may be problematic if no Gd is seen on MRI.
Gd has been shown in the Globus Pallidus (GP) and Dentate Nucleus (DN) on T1-weighted MR images. It is not clear what speciation (what Gd is attached to) to be shown on MRI. Since it is essentially only shown with prior administration of linear agents, and not with macrocyclics, it should reflect Gd dissociated from its ligand. In my opinion, since Gd associated with protein tends to have high T1 relaxivity, it is likely Gd in combination with protein macromolecules and not as Gd salts (Gd-phosphate, Gd-carbonate) is responsible .
My team has written a number of papers on Gd on MR images. Summarizing our work, and that of many other authors, the following is likely true:
High signal in the GP and DN is seen in the following settings:
1. if you had 5 MRIs with omniscan or optimark in the last 2-4 years,
2. if you had 10 MRIs with Magnevist in the last 2-4 years.
3. if you had 20 MRIs with Multihance in the last 2-4 years.
4. if you had 100 MRIs with Gadavist in the last 2-4 years.
5. it may never occur with Prohance or Dotarem.
If you don't fit into one of the first 3 above groups (or combination of them) then you will not have Gd shown in the brain on T1-weighted MR images.
But critical to know that this only describes one subset of Gadolinium Storage Condition (GSC), which may relate to GDD, but most often does not.
On top of that, this observation does not correlate well with retention of Gd in general. As mentioned above, Prohance and Dotarem may never show increased T1 signal, and yet Gd is retained in the body following these agents - it is just not dissociated.
GDD can arise after just 1 ml of a macrocyclic agent for MR arthrography.
So:
1. Gd in the brain on MRI reflects just a highly subselected form of GSC.
2. It has little bearing on whether GDD exists or not.
Depending on the reason for the review of MR studies for high signal on T1 in the brain on MRI, it may provide great disservice to you to have your brain MRI re-interpreted. If it is interpreted as 'negative for Gd' this could be misconstrued as not having any Gd, and hence no GDD.
If you do not fit into 1 of the first 3 of 5 groups above (or combination) then you won't have Gd in the brain on MRI.
Do not have your brain studied re-interpreted unless you know you are in one of the top 3 of 5 groups, and then you want to have confirmation.
Richard Semelka MD Consulting
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