Information overload
The detailed views of organs and tissues captured by magnetic resonance imaging can help doctors diagnose illness, offering more precise information than traditional X-rays. But the technology has its limits.
Two new studies have found that the expensive and still relatively new technology can also lead to unnecessary surgery.
University of Washington researchers reported in the current Journal of the American Medical Assn. that fast MRIs were no better than X-rays for patients with low back pain. Instead, MRI picked up more incidental problems, led to more specialist consultations and was more likely to land patients in an operating room for spinal surgery. In the end, they found, technology neither saved money nor assured that patients fared better than they would have with old-fashioned X-rays.
In the other study, presented June 1 at the American Society for Clinical Oncology meeting in Chicago, scientists said that although MRI can pick up breast cancers missed by standard mammograms, it also produces significant numbers of false positives that led to invasive and sometimes unnecessary biopsies.
X-rays produce simple anatomical images using radiation: The densest tissues absorb the most radiation and appear lightest. MRI uses radio waves and a strong magnetic field to scan the body; a computer helps translate the information into cross-sectional views.
In the breast cancer study, Dr. Mark E. Robson, a medical oncologist at Memorial Sloan-Kettering Cancer Center in New York City, said he didn’t discount the value of the high-tech diagnostic procedure for patients with the BRCA breast cancer gene mutations, a history of breast cancer or other major risks. High-risk women typically have more faith in a breast MRI, which typically runs about $1,000, than in a $100 X-ray mammogram, because it’s generally more sensitive and doesn’t use radiation, which can create cell mutations.
However, said Robson, the lead author of the study, “the downside is that it picks up a lot of things that are not cancer.”
An MRI requires highly trained radiologists who can determine “what things need to be biopsied and what things don’t.” A bad result on an MRI might even increase the chance that a worried woman might opt for prophylactic mastectomy, he said.
The conclusions of both studies were that MRI should be used cautiously. But many doctors are ordering the more expensive tests out of fear that if they miss a disorder, they could eventually be sued.
“No amount of imaging and no imaging tool can substitute for physician judgment and a clinical exam. We get into trouble when we rely exclusively on imaging,” said Dr. Pablo Villablanca, medical director of MRI at the UCLA Medical Center.
Villablanca said that it’s appropriate to use MRI when back pain also involves pain in the legs or other parts of the body, because the imaging can identify pinched nerves or worn-out joints that might require special treatment.
But he said one of the main contributors to spiraling health care costs “is that physicians are relying less and less on clinical judgment and more and more defaulting to imaging studies.”
