Introduction: Low back pain is the leading cause of disability worldwide. MRI is a commonly used diagnostic tool; however it does not consistently correlate with the patient’s symptoms. Traditionally, MRIs are performed in a supine position that unloads and decompresses the spine. MRIs performed in various positions may give a more dynamic view of the cause of symptoms.
Methods: Thirty-four low back pain patients who were sent for a standard MRI agreed to participate. In addition to the standard supine posture, the MRI was taken in 6 experimental postures including sitting upright, flexed, and extended, standing upright, flexed and extended. Two raters took various measurements at L3/L4, L4/L5 and L5/S1 for a total of 126 measures. Each subject served as their own control.
Results: The preliminary findings showed that 94% of the measures were not significantly different between the two raters.
In the sagittal view, 55 of the 108 measures were significantly different between the experimental and standard postures. The sagittal view anterior disc height in sitting neutral posture was significantly smaller than the standard posture by almost 2 mm. Both the left and right side neural foraminal height measures were significantly different at all levels.
In the axial view, 11 of the 18 measures were significantly different between the experimental and the standard supine postures. In the sitting neutral posture, the left and right neural foramen height was on average 0.70 mm larger.
Conclusions: This research quantifies the differences in spine structure measures that occur in various experimental postures. The additional information gathered from an upright MRI and its depiction of various structures under axial loading situations may correlate more reliably with symptoms leading to a more accurate diagnosis.
Patient Care: Clinically, MRI findings are considered in conjunction with physical examination of the patient and symptoms when considering a diagnosis. The positional MRI may show the effects of axial loading with sitting and standing, and may in turn, link the patient’s symptoms and lead to a more appropriate diagnosis.
Learning Objectives: Recognize the differences posture can make on MRI measurements and their effect on clinical correlation.
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