While there is a range of toxicity associated with the interventions used in clinical care and research, there are several unique issues to consider in a project that involves administration of gadolinium for MRIs that are performed for research reasons only. First, there is a potential severe toxicity related to a diagnostic procedure with no direct therapeutic value. Second, the toxicity appears to restricted either exclusively or almost exclusively to individuals with Stage 4-5 chronic kidney disease (GFR below 30 mL/min). There are no confirmed cases of nephrogenic systemic fibrosis/nephrogenic fibrosing dermopathy (NSF/NFD) in individuals with GFR above 30 mL/min. Estimates of NSF/NFD for patients on chronic dialysis are between 1-5% per gadolinium scan. Information on the risks for NSF/NFD is rapidly emerging and new information may change the approach to protecting research participants.
The National Kidney Foundation uses the following guidelines to describe the range of chronic kidney diseases:
Chronic Kidney Disease:
The following guidance must be followed at JHM:
- For research that involves normal research participants who are to receive a gadolinium scan, a creatinine indicative of kidney function consistent with Stages 1-3 in the past 30 days will be required.
- For research that involves gadolinium scans for research purposes, in addition to scans for clinical purposes, the Principal Investigator must include in the application to the IRB a specific plan for protecting patients from NSF/NFD caused by gadolinium exposure.
While very specific policy guidelines to minimize risk would be ideal, each study has slightly different issues that need to be considered. In studies where many research and clinical interventions have as high a risk of toxicity as gadolinium (for example, pediatrics and oncology), emphasizing the risks of gadolinium in consent forms may not be valuable to the participants and might mislead them that this is the only intervention with high risks.
Measuring renal function to determine stage of chronic kidney disease to assess potential risk for toxicity also will require clinical judgment. Serum creatinine is a reasonable measure of renal function for most patients, but can be misleading for individuals with low muscle mass due to chronic disease or those with reduced meat intake. Urinary clearance of 125I-iothalamate is the gold standard for measuring GFR, but is not practical for most assessments. Serum creatinine may not be an adequate measurement for some of the ill populations in research protocols, particularly children. Principal investigators should address in the application how they will assess renal function to adequately inform research participants about their risks when being exposed to gadolinium.