ABSTRACT
BACKGROUND:Primates are considered to be the most appropriate animal model of lumbar intervertebraldisc degeneration, but the disc degenerated characteristics of monkeys were rarely reported. OBJECTIVE:To verify the degenerated regularity and characteristics of lumbar intervertebral disks in rhesus monkeys with magnetic resonance T2 mapping and T1ρimaging technology. METHODS:The sagittal lumbar intervertebral disc magnetic resonance T2 weighted imaging,T2 weighted mapping imaging and T1ρweighted imaging of 63 adult rhesus monkeys were acquired on 1.5T magnetic resonance equipment. The T2-map value and T1ρvalue of lumbar intervertebral disc regions of interest were calculated on the post-processing workstation. RESULTS AND CONCLUSION:(1) This study obtained 425 better magnetic resonance images of lumbar intervertebral disks in adult rhesus monkeys. T2-map value and T1ρvalue of nucleus pulposus were most consistent by different persons, and the Kappa coefficient was more than 0.93. (2) The T2-map value and T1ρvalue of nucleus pulposus were both negatively correlated significantly with Pfirrmann grades (r=-0.842, P<0.01;r=-0.896, P<0.01). The T1ρvalue and T2-map value of nucleus pulposus were significantly statistical y different between Pfirrmann grades I-IV (P<0.001, P<0.001). The T1ρvalue of nucleus pulposus was negatively correlated significantly with Pfirrmann grade II-III (r=-0.517, P<0.01) and Pfirrmann grade IV-V (r=-0.499, P<0.01). The T2-map value of nucleus pulposus was also negatively correlated significantly with Pfirrmann grade II-III (r=-0.617, P<0.01) and Pfirrmann grade IV-V (r=-0.652, P<0.01). (3) The T2-map value of L1-2 and L2-3 segments nucleus pulposus were significantly lower than that in L6-7 and L7-S1 segments (P<0.05). (4) There were significant differences in age among the T1ρvalue and T2-map value of nucleus pulposus (r=-0.702, P<0.001, r=-0.730, P<0.001). (5) It is concluded that magnetic resonance T2 mapping and T1ρimaging technology can objectively and sensitively assess the degenerated process of nucleus pulposus in rhesus monkeys. The degeneration in upper lumbar segments (L1-2 and L2-3) was earlier and more severe than that in lower lumbar segments (L6-7 and L7-S1) in rhesus monkeys. Age is one of the most important factors in lumbar intervertebral disc degeneration of adult rhesus monkeys.