Jane H. Park1,2, Brittany C. Lee1,2, Jing Qi2,3
1Molecular Physiology, Vanderbilt University Medical School, Nashville, TN, USA; 2Radiology, Vanderbilt University Medical School, Nashville, TN, USA; 3Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China
Polymyositis (PM) is an inflammatory muscle disease characterized by severe proximal weakness, fatigue, and high serum levels of muscle enzymes. MRI has demonstrated heterogeneous composition of PM thigh muscles ranging from normal to inflamed and/or fat-infiltrated. With diffusion tensor imaging (DTI), ADC values showed increased water motion in inflamed muscles and decreased motion with fat infiltration. Eigenvalues (λ1, λ2, λ3) confirmed anisotropy in all PM muscles. Tractography demonstrated shorter and less uniform fibers in affected muscles. Unaffected patient muscles were not significantly different from control subjects. To our knowledge, this is the first DTI examination of inflammatory muscle diseases.