Magnetic Resonance Elastography Patient Scanning on Lower Leg Muscles and Trapezius

Principal Investigator: Kai-Nan An, Ph.D.
Project Coordinator: Qingshan Chen — chen.qingshan@mayo.edu

Improvements are constantly made in MRE for the calf, thigh and trapezius muscles, including modification of the jigs, incorporation of new inversion algorithms, and further development of fast MRE data acquisition methods. A new positioning and loading jigs for testing the lower leg muscles allowed us to fix the ankle in 10° increments from 40° plantarflexion to 30° dorsiflexion. Two MR compatible torque cells were incorporated into this device to measure the isometric plantarflexion or dorsiflexion moment. Visual feedback was given to the patients to maintain a constant muscle contraction. In trapezius MRE, a small pneumatic driven drum-like driver and a positioning jig was fabricated, and the optimal scan plane was identified. The subject was asked to lay prone in a relaxed position, and the positioning jog allowed the driver to vibrate over the spine of scapula and generate sufficient planar wave propagation in trapezius. We have successfully performed in vivo MRE scans on 67 healthy volunteers on various muscle groups and 4 patients with different muscle pathologies.