When Do I need Diagnostic Testing?

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Do I need an MRI?Question: This is a question asked by many patients who are attending physical therapy. Patients will say, “Years ago when I went to my doctor with low back pain, I would get an X-ray and maybe an MRI. Why didn’t they do that this last time? How do they know what’s wrong if I don’t have an MRI?”

Answer: The brief answer to this question is that recent research on the medical necessity of immediate imaging studies for low back pain is showing that immediate X-rays garner little information and expose patients to unnecessary radiation in the overwhelming majority of cases. Since X-rays only show bone and the spaces between bones, they generally are not very helpful in specifying the source of your back pain. MRI’s can be helpful in ruling out substantial nervous system pathology; however, for most patients, a conservative approach to treating back pain such as physical therapy can result in complete resolution of symptoms without the need for expensive testing. Also, while MRIs may divulge lots of information about your spine, this information is rarely helpful in determining the specific, precise source of your back pain. For the small percentage of patients who do not fully improve with conservative treatment, an MRI can be useful in planning for further, more invasive treatment techniques, such as injections, implantable pain-relieving devices, and/or surgery. There are a small percentage of cases of acute low back pain that require more significant work-up; for instance, for patients with clear nervous system involvement with large motor deficits such as drop-foot, progressive worsening of neurologic symptoms, or indications of possible infection, tumor, fracture, or cauda equina syndrome.

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