MRI Not Recommended For Patient With Shrapnel Lodged In Skull

DEAR DR. ROACH: I have a 3 mm piece of shrapnel lodged in my skull bone. This is a result of military action back in 1967. A recent X-ray continues to show the shrapnel after all these years. I would say that the piece is half in and half out of the skull bone.

At age 77, I am unable to have an MRI. I currently have Type 2 diabetes and a pacemaker. I also had prostate cancer, which is now post-radiation, and I have also had a stroke and a heart attack. Although I do not need an MRI right now, I am being proactive because I am concerned that I may need one in the future due to my medical conditions.

Should I have the shrapnel removed to allow for a future MRI? Although doctors tell me that a CT scan is as good as an MRI, I believe an MRI is always the better option. Or if I need an MRI, can I leave the shrapnel in place? -- T.

ANSWER: Thank you for your service. Although I admire your proactive nature, removing shrapnel from your skull bone is too risky to consider just for the prospect of maybe needing an MRI someday. While it is true that MRIs have many advantages over CT scans for some purposes, a CT scan is better for some medical indications and nearly as good for most.

It's likely that the shrapnel is steel- or iron-containing, and these can move in the strong magnetic field of the MRI if they are not firmly attached. Even if they are firmly attached, as it sounds like yours is, ferromagnetic metal (iron, nickel, cobalt and a few others) can heat up and cause pain and even tissue damage. So, a radiologist would be unlikely to perform an MRI on you.

Modern pacemakers (after the year 2000) are made with materials that are safer to use in an MRI scanner. A 2020 review of MRI scans done on people with older pacemakers (even before they were made safer) found that there were no complications to the patients or devices, so MRI scans can typically be performed on people with pacemakers.

DEAR DR. ROACH: I am a 65-year-old man in good health. Over the last 10 years, I have been prone to shivering. It's quite strange. I don't necessarily feel any colder than anyone else under the same circumstances. But once in a while, it will hit me wrong, and I will shiver when no one else does. It can even be inside, when the house temperature is supposedly 70 degrees Fahrenheit. But the chill just hits me after I take off my clothes or something like that. Instead of just being cold, I shiver. It is horrible and takes some time to go away.

My resting heart rate is around 50 bpm. Could this be a reason for it? Do you know of a way to stop this or what to do when it starts? -- C.C.

ANSWER: A low heart rate and being cold are both common conditions for men in their 60s and may not indicate anything wrong at all. However, shivering is a bit unusual at 70 degrees even if the person has very little body fat. One concern could be a low thyroid level, which causes both intolerance to cold and a low heart rate. A chronic, low-grade infection might do this, too. It's definitely worth getting checked out.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.