Eric Sigmund PhD, Presenter: Nothing to Disclose

Steven Baete, Abstract Co-Author: Nothing to Disclose

Thomas Luo, Abstract Co-Author: Nothing to Disclose

Mary Bruno RT, Abstract Co-Author: Nothing to Disclose

David Mossa, Abstract Co-Author: Nothing to Disclose

David Stoffel, Abstract Co-Author: Nothing to Disclose

Alisa Femia MD, Abstract Co-Author: Nothing to Disclose

Sarika Ramachandran MD, Abstract Co-Author: Nothing to Disclose

Andrew Franks MD, Abstract Co-Author: Nothing to Disclose

Jenny T. Bencardino MD, Abstract Co-Author: Nothing to Disclose

We have employed diffusion tensor imaging (DTI), intravoxel incoherent motion (IVIM), and a new dynamic DTI approach to evaluate the proximal lower musculature in a cohort of dermatomyositis (DM) patients and healthy controls and compared with their clinical workup.   

In this IRB-approved, HIPAA-compliant study, anatomical imaging, Dixon fat/water imaging , and diffusion imaging (DTI, IVIM, and dynamic DTI) were collected in bilateral thigh imaging of 6 normal controls (2M, 4F, ages 24-65, 42±16) and 7 DM patients (1M, 6F, ages 32-65, 56±11) in a Siemens Skyra 3 T scanner with body matrix and spine array coils. DTI (MD, FA, eigenvalues) and IVIM (Dt, fp, Dp) metrics were derived from each of 8 thigh muscle compartments bilaterally segmented on high resolution Dixon imaging. Single voxel dynamic DTI provided time series of radial and axial diffusion before and after a 3 minute unilateral leg lift exercise period, focusing on the anterior quadriceps (rectus femoris and vastus lateralis). The relative exercise response and rate of recovery were determined for radial and axial diffusion in each subject. In DM patients, correlations were performed with serum markers and manual muscle tests (MMT).

DM patients showed significantly larger fat fraction (FF), higher tissue diffusivity (Dt), lower pseudodiffusion (Dp), and lower perfusion fraction (fp) than controls. Dynamically, radial diffusion exercise response was significantly larger and slower to recover to equilibrium than controls, and showed significant inverse correlation with manual muscle test score.  

DM patients show significantly higher static FF and Dt, and significantly lower fp and Dp, than controls. Radial diffusion in DM patients shows significantly larger and longer-lived exercise response than controls. These are novel probes of muscle function that may dramatically enhance diagnostic power in this group. Ongoing work will investigate the prognostic potential of these markers in predicting response to immunosuppressive therapy.

Dermatomyositis is a degenerative muscle condition needing diagnostic/prognostic biomarkers. The sensitivity of diffusion imaging to microstructure, vascularity, and activity fulfills this need.

Sigmund, E, Baete, S, Luo, T, Bruno, M, Mossa, D, Stoffel, D, Femia, A, Ramachandran, S, Franks, A, Bencardino, J, Assessment of Thigh Muscle in Healthy Controls and Dermatomyositis Patients with Diffusion Tensor Imaging, Intravoxel Incoherent Motion, and Dynamical DTI.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013274.html