Gadolinium Use in Breast Cancer MRIs

Women who have been diagnosed with breast cancer or who are at high risk of developing the disease will often undergo a medical imaging procedure known as magnetic resonance imaging (MRI). The procedure involves an injection of a solution containing the chemical element gadolinium (Gd)—a silvery-white metal that has mild magnetic properties. In this capacity, gadolinium is referred to as a contrast agent.

Gadolinium is the most commonly used contrast agent for MRI and the one that is used in imaging for the screening, diagnosis, or monitoring of breast cancer.

What It Does

Gadolinium's properties can be put to good use in MRI because the technology utilizes magnetic pulses to create highly detailed, cross-sectional images of internal organs.

The gadolinium used for a breast MRI is chelated, meaning that it has been chemically bound to an amino acid so that it can be better absorbed by the body. When injected into a vein, the gadolinium particles circulate in the bloodstream and find their way into interstitial compartments (tissue spaces) where they can be detected by the magnetic fields generated by the MRI machine. Those signals are sent to a computer, which generates images of the breast tissue.

Benefits

What makes gadolinium unique is that it has seven unpaired electrons, the highest number that can possibly spin around a single atom. The speed by which these electrons spin directly influence the brightness of an MRI.

When injected in higher concentrations, gadolinium-based agents are better able to reveal lesions, tumors, and metastases (secondary cancer growths), as well as areas of increased vascularity in breast tissue (which typically occurs when blood flow is redirected to a tumor).

Because the gadolinium in MRI contrast dyes is chelated, it is more easily excreted from the body via the kidneys. As such, gadolinium is not considered toxic and does not expose you to radiation like X-ray-based technologies commonly used in cancer diagnosis (e.g., computed tomography or positron emission tomography).

Indications

In the same way that mammograms are performed using specialized X-ray equipment, the MRI equipment used for breast scans is also specialized. Referred to as MRI with dedicated breast coils, the machine is designed so that it conforms to various breast cup sizes and provides a clearer picture of a breast's vascularity and density.

A contrast-enhanced breast MRI may be indicated for different reasons, including:

• Screening women at high risk for breast cancer (due to family history, genetic testing, or other risk factors)
• Determining the extent of cancer after it has been diagnosed, including metastases or lymph node involvement
• Evaluating hard-to-assess abnormalities on a mammogram
• Routinely evaluating and monitoring a lumpectomy site after surgery
• Monitoring the size of a tumor when neoadjuvant chemotherapy is used to shrink the tumor prior to surgery
• Evaluating breast implants after breast reconstruction surgery to identify seepage or rupture

Types

The U.S. Food and Drug Administration (FDA) has approved a number of gadolinium-based contrast agents that are considered safe and effective. Some are designed for specific purposes (to image the liver or kidneys, for example), while others can be used to image multiple organ systems or conditions. Those commonly used for breast cancer include:

• Omniscan (gadodiamide)
• OptiMARK (gadoversetamide)
• Magnevist (gadopentetic acid)
• ProHance (gadoteridol)
• MultiHance (gadobenate)
• Ablavar (gadofosveset)
• Dotarem (gadoterate)
• Eovist (gadoxetic acid)
• Gadavist (gadobutrol)

In practice, gadolinium-based contrast agents are commonly referred to as "gad" or "gado" by MRI technologists.

Possible Risks 

MRI is generally considered safer than imaging procedures that expose you to ionizing radiation. However, recent research has suggested that there are certain risks, however slight, involved with gadolinium use.

Brain Retention

In 2014, a series of studies reported that gadolinium doesn't always entirely leave the body as previously assumed and can sometimes establish deposits in the brain. This led some to suggest that gadolinium deposits may cause neurologic disorders such as Parkinson's disease or multiple sclerosis (MS). To date, there is little evidence of this occurring.

A 2018 review of studies concluded there was no evidence of toxicity or cognitive impairment in people who had undergone frequent MRI or any variation in the rate of Parkinson's or MS in people exposed to gadolinium versus those who weren't.

Despite this, the FDA issued a series of safety announcements advising healthcare providers to counsel their patients about the risk of gadolinium retention, while conceding it could find "no harmful effects" associated with such deposits in the brain.

Nephrogenic Systemic Fibrosis

On the other hand, gadolinium has been linked to a condition called nephrogenic systemic fibrosis (NSF). This mostly occurs as a result of gadolinium exposure, triggering the thickening or hardening of the skin and fibrosis (scarring) in other parts of the body.

How gadolinium causes NSF is unknown, but it only tends to affect a small percentage of people with severe kidney disease, such as those on dialysis, who have undergone a kidney transplant, or who have acute or chronic kidney failure. Even so, only around 4 percent of this population will be affected.

Most of the reported cases involved a heart imaging procedure known as magnetic resonance angiogram (MRA) which uses up to three times the gadolinium used in a conventional MRI.

Alternatives

While uncommon, some imaging facilities can use iron oxide-based agents instead of gadolinium, which are believed to be safer because the body already contains iron.

Scientists are also exploring manganese-based contrast agents and even non-metal compounds for use with an MRI.

A Word From Verywell

As an important a tool as a breast MRI is, it is not for everyone. To start, it can be unreasonably costly for the screening of women with an average risk of breast cancer.

Still, in women with breast cancer or those at high risk of the disease, its capabilities and benefits outweigh any potential risks, including those associated with gadolinium use.