Rapid magnetic resonance elastography of muscle using one-dimensional projection

Purpose: To demonstrate the feasibility of 1D MR elastography (MRE) to rapidly assess skeletal muscle stiffness in vivo. Materials and Methods: Shear waves were induced in the vastus medialis muscle (VM) using a pneumatic driver at 90 Hz and 2D MRE data were collected. Spatially selective excitations were used to produce 1D projections of MRE data oriented along the direction of propagating waves in the muscle. Data were collected with the thigh muscles relaxed and contracted at 20% maximum voluntary contraction (MVC) and the knee flexed at 30 degrees. Results: The muscle stiffness measured at rest and in contraction with 1 D MRE was 3.69 +/- 0.80 kPa and 9.52 +/- 2.74 kPa, respectively, and 4.36 +/- 0.98 kPa and 9.22 +/- 1.29 kPa, respectively, with the 2D MRE technique. Conclusion: Muscle stiffness measured using 1D MRE was in agreement with 2D MRE while reducing the scan time by a factor of 4.