Quantitative Evaluation of Risk Factors for Low Back Pain in Young Patients Using Synthetic Magnetic Resonance Imaging and Proton Density Fat Fraction Analyses

Background: Lumbar intervertebral disc and paravertebral muscle degeneration are common causes of chronic low back pain (CLBP). However, the exact etiology of CLBP in young patients remains unclear. Identifying the risk factors for CLBP in young patients could expedite the development of effective preventive recommendations. Objectives: To identify the factors influencing the presence and severity of CLBP in young patients by analyzing the associations between the fat content of the paravertebral muscles, T2 value of the lumbar intervertebral disc (LIVD), and visual analog scale (VAS) score. Design: Data for 23 patients diagnosed with CLBP were compared to those of 20 healthy young individuals. Methods: The T2 values of the LIVD and fat content of the psoas major (PM), multifidus (MF), and erector spinae (ES) muscles for 23 young patients with CLBP and 20 healthy individuals were measured and compared using synthetic magnetic resonance imaging and proton density fat fraction analyses. Moreover, the factors (T2 values and fat content) associated with severe CLBP (assessed using the VAS score) were analyzed. Results: The fat content of the right MF and ES was higher in patients with CLBP than in healthy individuals ( p < 0.05). The T2 values of each LIVD in the CLBP and control groups were not significantly different ( p > 0.05). Moreover, the VAS scores did not correlate with the T2 values of the patients ( p > 0.05). The fat content of the bilateral MF and ES muscles was positively associated with the VAS score in young patients with CLBP (left MF: r = 0.506, p = 0.01; right MF: r = 0.532, p = 0.01; left ES: r = 0.636, p < 0.01; and right ES: r = 0.716, p < 0.01). Conclusion: Degeneration of the MF and ES may contribute to CLBP in young patients. In addition, the severity of CLBP is positively correlated with the degree of fat infiltration in the MF and ES.