Is MRI contrast a dangerous threat?

In early November, Chuck Norris filed a lawsuit against medical device manufacturers involving gadolinium-based contrast media, a chemical used in MRI imaging scans. The lawsuit stated that the gadolinium that doctors injected into his wife Gena to improve the clarity of her MRIs have left her “weak and tired and with debilitating bouts of pain and a burning sensation.”

As with any adverse effects involving medical procedures in the news, it is very understandable for a patient to become anxious whether they have already had the procedure or they are scheduled to have one.

Since the U.S. Food and Drug Administration (FDA) approved the use of gadolinium-based contrast agents (GBCA) for magnetic resonance imaging (MRI) use in 1998 to improve visibility of internal structures, gadolinium has been used in more than 300 million patients for diagnosis and treatment guidance. These contrast agents are composed of an organic component that tightly binds to and improves the stability and safety of the central gadolinium-heavy metal ion that is then eliminated from the body by the kidneys.

In fact, the overall risks of GBCA have been found to be small over multiple scientific studies. The adverse event rate for MRI contrast agents administered at clinical doses ranges from 0.07 percent to 2.4 percent. Most reactions are mild and physiologic and include nausea, vomiting, warmth or pain at the injection site, headache, a burning feeling, an unpleasant taste in the mouth and dizziness. Severe, life-threatening anaphylactic reactions can occur but are exceedingly rare at 0.001 percent to 0.01 percent of patients.

In its early days, GBCA was believed to be quite safe in all patients. But in 2000, nephrogenic systemic fibrosis (NSF) was first described. It’s a disease that causes fibrosis of the skin and subcutaneous tissues and also the lungs, esophagus, heart and skeletal muscles. Initial symptoms can include intense itching and skin thickening and can progress to joint immobility and possibly death. In 2006, several groups noticed a strong association between GBCA administration in patients with end-stage chronic kidney disease (CKD), particularly in patients on dialysis. Since then, the MRI contrast agent has been avoided in patients with advanced renal disease.

More recently, gadolinium deposits have been found within the brain tissue of patients who received multiple doses of MRI contrast media over their lifetimes. The FDA published a Safety Alert in July of 2015 indicating that they were actively investigating the clinical significance of the residual gadolinium. No adverse health effects have yet been discovered by the FDA or the European Union Agency, but the radiology community continues a rigorous investigation.

This is how side effects can be discovered over time. Since MRIs and their associated contrast agents have only been around for what is considered a short time in the medical community, long-term effects may not have been completely uncovered. When a few patients have reactions that were not previously known, these become what is known as “case reports” to the scientific community. Over time, many of these “case reports” can collect in numbers and facilitate recognition of new diseases and adverse treatment effects. Mrs. Norris’s case can potentially set a framework for providing feedback for clinical practice guidelines.

The American College of Radiology said in a statement that GBCA provides “crucial, life-saving medical information.” As a radiologist, the specialty that interprets these images, I have diagnosed infections, cancers, strokes, bleeding and many other things with the use of contrast-enhanced MRI when all other imaging was normal. We once had a patient that had a CT scan of the head without contrast come through the emergency room department that did not show any abnormalities. So an MRI was ordered with contrast that showed a small enhancing focus at the brain. This could have been many things including infection, a bleed or a tumor and may not have even been noticed if the MRI was performed without contrast. A follow-up scan was ordered, and the lesion tripled in size. After biopsy, the diagnosis came back as a glioblastoma multiforme — a devastating brain cancer. If it wasn’t for the MRI contrast agent, this likely would not have been discovered. After his tumor was resected, a subsequent MRI brain with contrast demonstrated that there was new nodular enhancement at the surgical bed. The patient needed to have another surgery to remove the recurrent malignancy.

As a physician, it is very much appreciated that Gena and Chuck Norris do not blame the doctors that cared for her. The truth is physicians use their numerous years of training and best judgment to do what they can for their patients. Every single medical procedure and treatment performed has the potential to cause unfavorable effects. In addition, most patients that come to the hospital or need procedures and imaging may already have an illness and may not return to 100 percent health ever again. Health care providers have to use a “risk-benefit” ratio to decide what possible dangers must be taken to help the patient.

For example, if a patient has symptoms and laboratory abnormalities from bile duct stones, an endoscopic retrograde cholangiopancreatography (ERCP) is needed to remove the stones but comes at the risk of pancreatitis, infection of the pancreas that can be very destructive to the body. Even something appearing so simple as a blood draw for diagnostic tests can also lead to adverse reactions such as a terrible infection. The physicians taking care of Mrs. Norris, in order to help her, used their best clinical decision to assist their patient on her road to recovery. In the case of GBCA, health care professionals do their best to limit contrast media use to circumstances in which the additional information provided by the contrast is necessary.

MRI with contrast has proven to be useful with often life-saving advantages. But patients should always keep in mind that with every single medical procedure, there are risks, and these must always be weighed with the possible benefits of receiving the procedure. And although it has been proven that very few patients have reactions to MRI contrast agents, it is still devastating to be one of those few patients.

So do not hesitate to ever ask your doctor questions. Together, you and your health care team should always work together to decide the best course of action for your wellness.

Karen Tran-Harding is a radiology resident.

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