Low back pain (LBP) is a common clinical condition, and non-specific LBP is believed to be associated with lumbar instability caused by paraspinal muscle (PSM) degeneration. Therefore, MRI evaluation of PSM degeneration can help predict the progression of low back pain-related diseases. At present, the most commonly used MRI parameters are the cross-sectional area (CSA) and fat infiltration (FI) of PSM. In order to assess the degree of PSM degeneration more accurately, modified parameters including functional CSA, relative CSA and muscle-fat infiltration index (MFI), have been designed. Advancements in MRI technology,such as the application of IDEAL-IQ, allow for early detection of changes in fat infiltration. Additionally, the proton density fat fraction (PDFF) derived from chemical shift encoding based water-fat MRI (CSE-MRI), also shows promise in studying PSM. Numerous MRI studies, both domestically and internationally, have aimed to establish the relationship between PSM degeneration and non-specific LBP, lumbar degenerative diseases, degenerative lumbar scoliosis, and osteoporosis. It has been found that PSM degeneration is affected by other factors such as intervertebral disc, articular process and endplate degeneration. Furthermore, PSM degeneration and scoliosis/kyphosis are also reciprocal causation. Higher fat content in the vertebral body and PSM is associated with increased bone fragility, while vertebroplasty following osteoporotic vertebral fracture can delay PSM degeneration and improve quality of life.

Lumbar vertebrae; Paraspinal muscles; Magnetic resonance imaging