MRI and MRA Contrast, Gadolinium Based Contrast Agents (GBCAs)
Contrast is routinely utilized in certain MRI and MRA exams. The injection of contrast highlights or enhances organs, tissues and vessels allowing the radiologists to differentiate specific tissues for pathological processes.
Contrast is typically injected into a vein for most exams. For MR Arthrogram injections the GBCA is diluted and injected with imaging, fluoroscopy or ultrasound guidance by a radiologist or physician into the affected joint.
Gadolinium is a paramagnetic metal ion; it is different from iodinated contrast agents used in CT, Xray and Interventional Radiology procedures. GBCAs are chelated to reduce the chances of toxicity that could result from exposure to the gadolinium. At this time, only certain patients who receive GBCAs appear to be at an increased risk for developing a serious systematic fibrosing disease, Nephrogenic Systemic Fibrosis, NSF.
GBCAs are typically filtered out of the bloodstream by the kidneys, although certain agents are also filtered out through the liver and biliary system. Creatinine levels and estimate glomular filtration rates, eGFR, are important in specific patient populations. The following are outpatient risk factors used to determine when a creatinine level and eGFR would be appropriately acquired prior to the MRI or MRA:
- Renal Disease
Including solitary kidney, kidney surgery, transplant or tumor, history of known cancer involving the kidney(s).
- History of Hypertension
- History of Diabetes
- History of severe Hepatic Disease/Liver Transplant or pending Liver Transplant
See the chart below for guidance on the patient guidelines as to when a creatinine level would be appropriate to be drawn. Do not hesitate to contact our facility with any questions.
Table for Outpatients with risk factor(s) for compromised renal function.
|Pt doesn't have a prior eGFR||Obtain eGFR within 6 weeks of exam|
|Pt's prior eGFR is >60 and >6mo's old||Obtain eGFR within 6 weeks of exam|
|Pt's prior eGFR is >60 and >6mo's old
(Pt hass possible "unstable state": dehydration, frebile illness, sepsis, heart failure, recent hospitalization, advanced liver disease, and or abdominal surgery. Any of these may result in acute deterioration of renal function)
|Obtain eGFR within 2 weeks of exam|
|Pt's prior eGFR is >60 and >6mo's old
(Pt does not have any "unstable states" listed directly above.)
|No New eGFR Needed|
|Prior eGFR of 30 to 59 >2wks||Within 2 weeks|
|Prior eGFR <30||Within 1 week|
|Patients on Dialysis Do NOT Need a New eGFR, it's not applicable|
Patients on dialysis may receive a GBCA injection. The appropriateness of giving a GBCA is determined between the ordering physician and the radiologist. In conjunction with ACR suggested guidelines, these patients receiving a GBCA injection will have a dialysis appointment set up following the MRI where their nephrologist will assume responsibility of further dialysis care instructions.
Breastfeeding mothers may also receive GBCAs; studies and literature have found that less than 0.04% of GBCAs are excreted into the breast milk. The following options for the mother when a GBCA injection will be part of their MRI are completely up to them, an informational sheet will be given to them when they arrive for their exam. If you would like one in advance, please contact our facility. Breastfeeding mothers may decide to pump/express milk in advance to have an adequate supply prior to the GBCA injection. After the injection, they may continue to breastfeed normally or abstain from breastfeeding for 24 hours after the GBCA injection and pump/express and dump the milk.
Below are links to the FDA and ACR websites with information and guidelines regarding GBCAs and contrast safety, which our facility follows with radiologist guidance.