Fast Imaging Methods Of Magnetic Resonance Acoustic Radiation Force Imaging For Ultrasonic Neuromodulation

Ultrasonic neuromodulation is a non-invasive and targeted deep brain stimulation technology,which has great potential in the treatment of neurodegenerative diseases such as Alzheimer’s disease and epilepsy.However,the reflection and scattering effects on ultrasound wave of the skull distorts the ultrasonic focal point,which is unfavorable to the safety and effectiveness of ultrasonic neuromodulation.Magnetic resonance acoustic radiation force imaging（MR-ARFI）can provide accurate ultrasound focal point positioning for ultrasonic neuromodulation.However,MR-ARFI suffers from the long imaging time.The acceleration of MR-ARFI imaging without compromising the positioning accuracy becomes highly demanding for ultrasonic neuromodulation.This study proposed to accelerate the MR-ARFI from both the sequence design and under-sampling scheme,aiming to achieve the higher data acquisition efficiency without sacrificing the positioning accuracy.The experimental results showed that by adding an eddy-current matching gradient before the motion encoding gradient in MRARFI imaging sequence,the additional reference images for the eddy-current correction becomes unnecessary,reducing the imaging acquisition time by two folds.Besides,by incorporating the compressed sensing algorithm based on time difference（TED）to reconstruct the under-sampled data of MR-ARFI,the displacement information could be recovered from the under-sampled data（up to 8x acceleration）precisely.In addition,this study also realized the real-time reconstruction of TED algorithm based on the open source framework of Gadgetron.This work meets the requirements of researchers and clinicians for the rapid and real-time MR-ARFI for ultrasonic neuromodulation.