Lumbar Intervertebral Discs Degeneration：A Quantitative Evaluation by Using T2 Mapping / 中国医学影像学杂志

ABSTRACT

PurposePifrrmann scoring based on T2WI can only evaluate intervertebral disc qualitatively and is easily affected by the surrounding environment and imaging parameters. The present study attempted to make a quantificational study on lumbar intervertebral disc degeneration by using MR T2 mapping sequence so as to improve its diagnosis.Materials and Methods Sagittal T1FSE, sagittal and axial T2FSE, sagittal T2 mapping sequence were performed on 265 lumbar intervertebral discs from 53 subjects. The MR imaging was analyzed and all the discs were classified according to Pifrrmann scoring. T2 relaxation time of the discs was calculated and statistical analysis was conducted on its correlation.Results Among the 265 discs, 5 (1.9%) were scored as Pfirrmann I, 153 (57.7%) were scored as Pfirrmann II, 86 (32.3%) were scored as Pfirrmann III, 20 (7.5%) were scored as Pfirrmann IV, 1 (0.38%) were scored as Pifrrmann V. The average anterior annulus T2 values showed no difference between every Pfirrmann grade (P>0.05), while the difference of average posterior annulus T2 values was significant between groups (P<0.05). The relaxation time of anterior annulus was signiifcantly shorter than that of posterior annulus in the discs of Pifrrmann II-IV, whilst the reverse occurred in the discs of Pifrrmann I (P<0.05). The differences of the relaxation time of nucleus pulposus T2 values were signiifcant between groups of Pifrrmann grade I to IV (P<0.05). The T2 relaxation time of each partition of nucleus pulposus (ROI2/ROI3, ROI3/ROI4, ROI2/ROI4) was signiifcantly correlated (r=0.86, 0.76 and 0.63,P<0.05), the T2 relaxation time of anterior annulus and posterior annulus had no correlation (r=0.09, P<0.05), and the nucleus pulposus T2 values and Pfirrmann grade were negatively correlated (r=-0.78,P<0.05).Conclusion MR T2 mapping can quantitatively evaluate the T2 relaxation time of lumbar intervertebral discs, and is signiifcantly correlated with Pifrrmann grades.