A new four-area method for evaluating biochemical changes in lumbar facet joint degeneration at T2* mapping

Abstract

Abstract Purpose To investigate the diagnostic efficacy of a new four-area method for evaluating biochemical changes in lumbar facet joint (LFJ) degeneration at T2* mapping. Methods Fifty-eight patients with low back pain underwent standard MRI protocols and axial T2* mapping. Morphological evaluation of LFJ was performed on T2-weighted imaging according to Weishaupt grading system. T2* value of LFJ was measured at T2* mapping using all-inclusive and four-area methods, respectively. Inter-observer reliability for continuous and categorical variables were respectively evaluated using Pearson correlation coefficient and Kappa value. For evaluating the correlation between continuous variables and ordered categorical variables, one way ANOVA or Kruskal-Wallis test was used. Results In the analyses of both all-inclusive and four-area methods, the mean T2* value of grade 0 LFJ was higher than those of grade I, grade II and grade III LFJ, and a downward trend of T2* value was observed as the grade of LFJ rised except grade III. The mean T2* values of LFJ obtained by all-inclusive method were higher than those obtained by four-area method, except grade 0 LFJ. Besides, four-area method had a perfect inter-observer reliability with PCC of 0.992 (p = 0.000), higher than that of all-inclusive method with PCC of 0.943 (p < 0.001). Conclusions Being more reproducible and accurate than conventional all-inclusive method in the measurement of T2* value, the new four-area method can be used in evaluating biochemical changes in LFJ degeneration at T2* mapping.