Multifidus Muscles Lipid Content Is Associated with Intervertebral Disc Degeneration: A Quantitative Magnetic Resonance Imaging Study

STUDY DESIGN: Cross-sectional study. PURPOSE: To determine the association between fatty degeneration of the multifidus muscle (Mm) and intervertebral disc degeneration (IVDD) using quantitative magnetic resonance imaging (MRI). OVERVIEW OF LITERATURE: Few studies have reported on quantitative MRI analysis of the relation between the Mm and IVDD. METHODS: The subjects with chronic low back pain comprised 45 patients (19 males, 26 females; mean age, 63.8±2.0 years; range, 41–79 years). We analyzed the intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) of the Mm using magnetic resonance spectroscopy. The T2 values of the anterior annulus fibrosus (AF), nucleus pulposus (NP), and posterior AF were evaluated using MRI T2 mapping. We compared the possible correlations of IMCL and EMCL of the Mm with the T2 values of anterior AF, NP, and posterior AF. RESULTS: There was a significant negative correlation between IMCL and T2 values of the anterior AF (r=−0.65, p<0.01). There were no significant correlations between the IMCL and T2 values of NP (r=−0.16, p=0.30) and posterior AF (r=0.07, p=0.62). There were no significant correlations between the EMCL and T2 values of the anterior AF (r=−0.11, p=0.46), NP (r=0.15, p=0.32), and posterior AF (r=0.07, p=0.66). After adjustment for age and sex using multiple linear regression analysis, there was a significant negative correlation between the IMCL and T2 values of anterior AF (standardized partial regression coefficient=−0.65, p<0.01). CONCLUSIONS: The results indicated that IMCL of the Mm might be accompanied with anterior AF degeneration. Therapeutic exercises using IMCL of the Mm as evaluation index might have the potential to identify novel targets for the treatment and prevention of IVDD.

Analysis of Neuropathic Pain Using Magnetic Resonance Imaging T2 Mapping of Intervertebral Disc in Chronic Low Back Pain

STUDY DESIGN: Cross sectional study. PURPOSE: The study aimed to analyze mechanisms underlying chronic low back pain (CLBP) using magnetic resonance imaging (MRI) T2 mapping of the intervertebral disc (IVD). OVERVIEW OF LITERATURE: MRI T2 mapping utilizes the T2 values for quantifying moisture content and collagen sequence breakdown. We previously used MRI T2 mapping for quantifying the extent of IVD degeneration (IVDD) and showed a correlation between the degeneration of the posterior annulus fibrosus (AF) and CLBP. METHODS: We enrolled 40 patients with CLBP (17 males, 23 females; mean age, 50.8±1.6 years; range, 22–60 years). IVDs were categorized as the anterior AF, nucleus pulposus (NP), and posterior AF, and T2 value for each disc was measured. T2 values, assessed using the Japanese neuropathic pain (NeP) screening questionnaire, of the NeP and nociceptive pain (NocP) groups were compared. RESULTS: T2 values of the NocP and NeP groups were 64.7±5.6 ms and 58.1±2.3 ms for the anterior AF; 67.0±4.6 ms and 59.6±2.1 ms for NP; and 70.7±4.6 ms and 51.0±1.2 ms for the posterior AF, respectively. T2 values for IVDD were significantly lower in the NeP group than those in the NocP group (p<0.01). CONCLUSIONS: The results indicate a correlation between the degeneration of posterior AF and NeP. MRI T2 mapping may be beneficial for detecting NeP caused by IVDD and can help formulate targeted analgesic therapies.