Convertible pneumatic actuator for magnetic resonance elastography of the brain

Abstract

Here we present a novel pneumatic actuator design for brain magnetic resonance elastography (MRE). Magnetic resonance elastography is a phase contrast technique capable of tracing strain wave propagation and utilizing this information for the calculation of mechanical properties of materials and living tissues. In MRE experiments, the acoustic waves are generated in a synchronized way with respect to image acquisition, using various types of mechanical actuators. The unique feature of the design is its simplicity and flexibility, which allows reconfiguration of the actuator for different applications ranging from in vivo brain MRE to experiments with phantoms. Phantom and in vivo data are presented to demonstrate actuator performance.

Observation of direction-dependent mechanical properties in the human brain with multi-excitation MR elastography

“…AP excitation is the most common type of excitation used in brain MRE, generally achieved through pneumatic actuation of a soft pillow [4, 45] or a head rocker driven by remote electromechanical actuation [25, 46, 47]. LR excitation from a bite bar [48, 49, 50], lateral pneumatic actuation [51], or scanner table vibration [52] is less commonly employed. In this case, we can expect that the use of AP excitation will result in highly repeatable measurements of WM tracts, as has been reported previously [21, 47], and that these measurements should be considered less sensitive to the excitation mode.…”

Review of MR elastography applications and recent developments

“…A number of techniques have been developed over the years to do this, including bite bars, actuators placed under the head, and devices that vibrate a holder the head rests in (10,16,168,170,172,179). To further improve patient comfort and to reduce the complexity of brain MRE hardware, researchers have pursued alternative ways of producing the brain tissue motion necessary for MRE.…”

Functional MRI of the thoracic spinal cord during vibration sensation

“…The vibration sensation was generated with an MR‐compatible custom‐built actuator (13). The actuator probe had an approximately 5 × 13 cm contact area with the body and was set to vibrate at 50 Hz.…”