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Forecasting your body's future
3-D color technology helps patient and physician understand medical issues


January 2015

A 3-D print of a portion of the knee has color on it to show pressure points on the joint.

Your knee hurts, you get a MRI. But what does it really show? While your doctor knows what they mean, those black-and-white MRI images can seem as lifeless as the Kansas landscape in "The Wizard of Oz."

Technology that turns MRI data into a three-dimensional color map of the knee is on its way, helping both patient and doctor see the problem.

The map can even be turned into a life-size model, created by a 3-D printer, that can help forecast when knee replacement will be necessary. "Showing the patient something in color can help convince the patient what medical procedures and interventions they need," says Robert D. Peters, a project manager at GE Healthcare in Waukesha. "It helps them to be more informed."

Peters jokes that some of his runner friends might want to keep their knee models as a sort of trophy. During an operation, of course, the 3-D-printed model serves a more practical purpose, giving the surgeon a point of reference for the procedure.

While 3-D printers have come onto the consumer market in just the last few years, MRI machines have been around since the ’80s. Magnetic resonance imaging uses the body’s natural magnetic properties to produce detailed images from any part of the body — about 90 images for knee MRIs. A GE team headed by Peters is partnering with a New York-based company to develop software that creates a single, comprehensive picture.

This so-called digital segmentation view of the knee aims to improve the diagnosis of osteoarthritis, a degeneration of the cartilage that affects about 27 million Americans. People over the age of 65, the obese and those who are sedentary are most at risk for osteoarthritis, according to the Centers for Disease Control and Prevention.

There is no effective drug therapy for osteoarthritis. Cortizone shots only numb the pain and can lead to even more damage, says Peters. "It’s important you catch it as early as possible, so you can either modify your exercise or perhaps take steps to repair the cartilage," says Peters.

Even in a healthy knee, that important layer of cartilage is not uniformly thick. At best, it measures about 3/16ths of an inch — that shows up as purple on the new type of picture. But in a knee wracked by osteoarthritis, the cartilage can be completely gone and displays as black.

Taking advantage of the new imaging, some patients could have MRIs at regular intervals so that damage can be monitored, says Peters. That would include people who have sustained an ACL tear; half of such patients develop osteoarthritis, usually just 10 or 12 years later.

By 2016, it is estimated that as many as 2 million Americans a year will need cartilage repair surgery, and another 1 million will have total joint replacement. Knee replacements usually last from 15 to 20 years, according to the American Association of Hip and Knee Surgeons. "For younger folks, you want to delay, whenever you can, the first full-joint replacement you have," Peters explains.


This story ran in the January 2015 issue of: