Important considerations for an MRI scan
There are a number of important factors to take into
consideration for an MRI scan, including limitations
with interpretation of findings and the timing of when
an MRI scan should be performed.
Evaluating MRI scan results
First, the difficulty
with the results of an MRI scan, as with many other
diagnostic studies, is that the "abnormality" that
shows up on the MRI scan may not actually be the cause
of pain. Numerous clinical studies have shown that
approximately 30% of individuals in their thirties
and forties have a lumbar disc herniation on their
MRI scan, although they do not have any back pain.
Therefore, an MRI scan cannot be interpreted on its
own. Everything seen on an MRI needs to be well-correlated
to the individual patient’s situation, including:
-
Symptoms (such as the duration, location, and severity
of pain)
-
Any neurological deficits on their physical examination
Another important consideration with MRI scans is
the timing of when the scan is done. The only time
an MRI scan is needed immediately is when a patient
has either:
Fortunately, both of the above situations are rare.
When to have an MRI scan to diagnose back problems
When
patients have predominantly leg pain and a lumbar disc
herniation is suspected, MRI scans are usually recommended
early in a patient’s course of pain.
This is because surgery for a lumbar disc herniation
generally carries few unwanted side effects (morbidity)
and leads to an early return to normal function for
the patient.
When patients have primarily low back pain, generally
the only surgical treatment available is a lumbar spinal
fusion. This type of spine surgery does carry a reasonable
amount of unwanted aftereffects (morbidity) and a longer
healing time. Therefore, physicians often recommend
waiting 3 to 6 months (after the onset of low back
pain) before having an MRI scan done in order to see
if the pain will get better with conservative treatments.
As a very general rule, if the results of the MRI
scan are not going to affect a patient’s further
treatment—and patient will continue with non-surgical
treatments such as chiropractic treatments, physical
therapy and medications—waiting to obtain an
MRI scan in most situations is a reasonable option.
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