Low back pain and osteoarticular degeneration or injury is the leading worldwide cause of years lost to disability, accounting for 17 % of all patients with disabilities and its burden is growing alongside the increasing and aging population. The anatomical regions of the intervertebral disc include the central nucleus pulposus, the peripheral fibrocartilaginous annulus fibrosus, and the superior and inferior cartilaginous endplates (CEP). The CEP is a thin layer of hyaline cartilage located between the avascular intervertebral disc and the bony vertebral endplate. The endplate cartilage consists of chondrocytes interspersed throughout an extracellular matrix of proteoglycans, collagen (types I and II), and water. It plays an important role in the function and homeostasis. The CEP has been considered the pathway between the largely avascular disk tissues and the blood supply of the vertebral body and thus provides nutrition for disk cells. Many musculoskeletal tissues, including the CEP, cartilage-bone interface of articular joints, entheses, tendons, and ligaments, have components with very short T2 values (much less than 1 msec), which are orders of magnitude shorter than that of the nucleus of the disk (~100 msec). In a conventional pulse sequence, such as proton density-weighted spin-echo (SE) or fast SE, with standard clinical section profile, the minimum echo time (TE) is typically 10 msec, which is much longer than that needed to capture the short-lived signal from these tissues. Recently, ultrashort echo sequence UTE technology has been introduced, and the TE time can be as low as 0.008ms. This range of TE is sufficient to capture signals from the cartilage endplate before it decays. With using new MRI technology, such as IR-UTE, UTE-MT, UTE-T2*mapping, Maigc, DTI, and IVIM, which can quantitative tissues that have previously been "invisible" at conventional MR imaging, and provide imaging basis for early diagnosis of injury at molecular level. The purpose of this study was to investigate the clinical application value of different MRI sequences in spine and joint.

Inclusion Criteria:

• 1.The patient had history and clinical symptoms of low back pain and joint sports injury 2.The patient had a history of osteoporosis; 3.There was no contraindication of MRI; 4.The patient who has clear lumbar intervertebral disc degeneration or herniation or osteoporosis or joint sports injury found by routine CT or MRI examination, and the clinical symptoms were consistent with the image.

Exclusion Criteria:

• 1. Patients with previous history of lumbar or joint surgery; 2. Patients with congenital bone deformity; 3. Patients with history of lumbar tumor and infection; 4. Cognitive function is limited or mental illness can not cooperate with imaging.

All suspected patients with osteoporosis and low back pain meet the inclusion criteria will include in this study. And patients who meet the criteria of the normal control group will include in this study.