Limitations of MRIs

Dr Robert Hrisak head shot

Magnetic resonance imaging (MRI) is helpful because it allows us to see nerves, discs, and other soft tissues that are hard to visualize with plain X-rays.  However, it has its limitations:  It often shows “problems” where there are no “problems.”  Research has shown that 20-76% of people without symptoms show disc herniation on an MRI.  A study published in the March 14, 2013 issue of the New England Journal of Medicine describes the dilemma faced by doctors.

Writing in HealthDay, Serena Gordon describes the results of the study:

“The current study included nearly 300 people randomly assigned to receive either surgery or conservative care for their sciatic pain, all of whom had signs of disc herniation on their initial MRI.  A follow-up MRI was done one year later, and the two MRIs were compared with patient results.”

“After a year, 84 percent of those in the study reported successful treatment.  Follow-up MRIs showed that 35 percent of those with a favorable result still had disc herniation compared to 33 percent of those with an unfavorable result.”

“Favorable outcomes were reported in 85 percent of those with disc herniation on their follow-up MRI and in 83 percent of those without disc herniation, according to the study.”

In addition to disc herniation, Nancy Walsh, a staff writer for MedPage Today, reports that “nerve-root compression was present on MRI in 24% and 26% of patients reporting favorable and unfavorable outcomes, respectively.”  “Visible scar tissue was present among 88% of patients who had undergone surgery, in most cases surrounding the nerve root.  Among patients with scar tissue, 86% reported a successful outcome, as did 75% of those without scarring.”

Dr. Devon Klein, chief of musculoskeletal radiology at Lenox Hill Hospital in New York City, said it well:  “You can’t treat the MRI.  You have to treat the patient.”

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