Assessment of apparent diffusion coefficient in lumbar intervertebral disc degeneration

The aim of this study was to determine the relationship between the apparent diffusion coefficient (ADC) and lumbar intervertebral disc degeneration using diffusion-weighted magnetic resonance imaging (DWI). Using a 3 T magnetic resonance scanner, DWI of the lumbar spine was assessed in 109 patients, with a total of 545 lumbar discs analyzed. Apparent diffusion coefficient values were recorded for each disc, and all discs were visually graded by two independent observers using Pfirrmann's grading system. Apparent diffusion coefficient values of disc were tested by correlation with qualitative clinical grading of degeneration severity, patient age, and sex. Correlations were investigated using Pearson's and Spearman's rank correlation analysis, and multiple regression analysis. Intervertebral disc degeneration was negatively correlated with ADC values of all levels (Spearman's correlation coefficient ranged from -0.381 to -0.604, p < 0.001). There was a significant negative association between age and ADC values at all spinal levels (Pearson's correlation coefficient ranged from -0.353 to -0.650, p < 0.001). When stepwise regression models were analyzed, both disc degeneration and age remained negatively associated with ADC values at each lumbar level (standardized coefficients ranged from -0.231 to -0.505, p < 0.01 and standardized coefficients ranged from -0.179 to -0.523, p < 0.05 respectively). Apparent diffusion coefficient values obtained using DWI can assess lumbar intervertebral disc degeneration, and the ADC values were negatively correlated with the degree of disc degeneration.