Study Design. Cross sectional study.
Objective. The goal of this study is to identify relationships between objectively measured and subjectively scored parameters and reported pain.
Summary of Background Data. Studies have demonstrated the unreliability of magnetic resonance imaging (MRI)–based parameters to identify pathological pain generators of chronic low back pain, but they were based on visual inspection and subjective assessment of lumbar disc features. Advancements in computer image analysis provide objective measurements of lumbar disc features.
Methods. Two radiologists evaluated 39 axial and sagittal T1- and T2-weighted MR images of patients with chronic axial low back pain (age, >65 yr) and graded 4 subjective lumbar disc parameters (T2 signal intensity, nucleus shape, Modic changes, and osteophyte formation) whose sum is the cumulative MRI score. Objective parameter, MRI index, was calculated as the product of the measured lumbar disc area and total disc MRI signal intensity. Discs were sorted from least to the most degenerated relative to each parameter. Pearson correlation coefficient and multiple linear regression analysis were performed between the reported pain score and each parameter.
Results. The most and least degenerated discs in each patient, as assessed by MRI index, had the highest negative and positive correlation coefficient and regression weight contribution, respectively. All subjective parameters had low correlation coefficients and regression goodness of fit.
Conclusion. Although limited by small sample size, the objective parameter, MRI index, can be a potential imaging biomarker used to identify possible pain generators. This study presents a potential new application of MR imaging in identifying pain generators of patients with chronic low back pain.
Level of Evidence: N/A
Lumbar disc degeneration is a potential source of pain for patients with chronic low back pain. The most and least degenerated discs in these patients, as assessed by objectively measured magnetic resonance imaging parameters, had the highest negative and positive correlation coefficient. All subjectively scored parameters had low correlation coefficients.
Departments of *Orthopaedic Surgery
¶Anesthesiology, University of Pittsburgh, Pittsburgh, PA
‖Geriatric Research Education and Clinical Center, Veterans Administration Pittsburgh Healthcare System, Pittsburgh, PA; and
**Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA.
Address correspondence and reprint requests to Gwendolyn Sowa, MD, PhD, Department of Physical Medicine and Rehabilitation, 3471 5th Ave, Suite 201, University of Pittsburgh, Pittsburgh, PA 15213; E-mail: firstname.lastname@example.org
Acknowledgment date: January 31, 2013. First revision date: September 16, 2013. Second revision date: December 12, 2013. Acceptance date: December 12, 2013.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Pittsburgh Claude D. Pepper Older Americans Independence Center (AG024827) and Dennis W. Jahnigen Career Development Scholars Award, American Geriatrics Society funds were received to support this work.
Relevant financial activities outside the submitted work: grant, board membership, grants/grants pending and royalties.