Can diffusion tensor imaging and tractography represent cross-sectional area of lumbar multifidus in patients with LUMBAR spine disease?

Introduction: Cross-sectional area (CSA) is a useful measurement to evaluate the lumbar multifidus, but it cannot reflect the morphological characteristics of the entire muscle. Recently, diffusion tensor imaging (DTI) and tractography (DTT) have been used to assess 3-dimensional muscle structures both qualitatively and quantitatively. In this study we investigate the correlation between CSA and multifidus volume and the clinical utility of DTI and DTT. Methods: Twenty-eight lumbar multifidi from 14 subjects with lumbar spine disease were analyzed. We conducted correlation analysis between CSA from conventional magnetic resonance images and DTI-derived parameters, including muscle volume, fractional anisotropy (FA), and mean diffusivity (MD); we performed morphological assessment using DTT. Results: Multifidus volume had a strong positive correlation with CSA (r = 0.760, P < 0.001). Neither FA nor MD correlated with CSA. Multifidi spanning fewer vertebral segments were smaller in volume. Discussion: DTT can be a valuable tool to visualize and quantify the lumbar multifidus in lumbar spine disease. Muscle Nerve 57: 200–205, 2018.