All the hospitals I’ve worked in, and I presume all hospitals nation-wide, have a questionnaire that all patients must respond to prior to getting an MRI. It asks about metal implants (such as cardiac pacemakers), piercings, and tattoos that, if present, would presumably prevent the patient from getting an MRI. But, after researching the issue, it appears that in the case of tattoos, an MRI is not completely out of the question as a diagnostic tool.

In the majority of cases, MRIs are perfectly safe for individuals with tattoos. An MRI is an imaging tool that would be used to look for conditions like infection of the brain or spine, multiple sclerosis, and various forms of inflammation. MRIs are especially useful in early diagnosis of stroke.

MRI stands for Magnetic Resonance Imaging, which is a radiological method for taking pictures of the inside of our bodies in the form of very thin “slices”. Unlike x-rays and computed tomographic (CT) scans, which use radiation, MRI uses powerful magnets and radio waves to create images.

Pre-MRI questionnaires ask about metal implants, pacemakers and piercings because the powerful magnetic force created by the machine can pull these metal components of the body toward the machine, posing a potentially fatal situation. Considering this risk, why would you get an MRI in the first place? As mentioned above, they are better than CTs for diagnosing strokes in their earliest stages, and they are the preferred imaging modality for identifying brain tumors, as well as for diseases of tendons, ligaments, and the spinal cord.

Tattoos are asked about in the questionnaire because the ink used for black or dark brown tattooing may contain compounds of iron oxide that have magnetic properties and may cause a burning sensation during MRI. Iron oxide is more likely to be a component of older ink, from tattoos that are 20+ years old. Newer tattoos may contain this type of ink, but it is less likely. The other pigments used for tattooing—namely carbon (black), titanium dioxide (white), copper phthalocyanine (blue, green), and indigoid (red)—do not contain metallic components and therefore do not have magnetic properties.

Drs.Tope and Shellock published a report in the Journal of Magnetic Resonance Imaging of 135 subjects who underwent MR imaging after having permanent cosmetics applied . Of these, only two individuals (1.5%) experienced problems; one subject reported a sensation of “slight tingling” and the other subject reported a sensation of “burning”; both sensations were transient in nature. Based on these findings and information in the peer-reviewed literature, Tope and Shellock concluded that MR imaging may be performed in patients with tattoos/permanent cosmetics, without any serious soft tissue reactions or adverse events.

A few take home messages here: A) if you’re going to get a tattoo, ask the tattoo artist if there is iron oxide in the ink he or she is using, and try to avoid iron oxide-containing ink in general; B) if you already have a tattoo and must get an MRI, be sure to tell the MRI technician about it and say something if you feel any burning or tingling at the tattoo site (you can communicate with a technician the entire time you are in an MRI machine). Applying cold compresses to the tattoos has been suggested to counteract the MRI-induced heating.

Most importantly, the presence of tattoos or permanent cosmetics should not prevent a patient from undergoing MR imaging. The benefits of MR imaging for diagnosis of potential disease far outweigh the miniscule risk of having an adverse reaction at the tattoo site.