Abstract #4132

SNR Trade-Offs in MR-ARFI of Focused Ultrasound in the Brain

Elena Kaye^1,2, Kim Butts Pauly¹

¹Radiology, Stanford University, Palo Alto, CA, United States; ²Electrical Engineering, Stanford University, Palo Alto, CA, United States

MRgFUS is of interest in the treatment of various brain pathologies, such as tumors and neuropathic pain. One way to visualize the focal spot prior to the treatment relies on MR acoustic radiation force imaging. A recent implementation of MR-ARFI used a diffusion-weighted 2DFT sequence with a low b-value. The goal of this work was to find the optimum b-value for the displacement sensitizing gradient in MR-ARFI, relevant to in vivo human imaging. The optimal b-value of 33 s/mm2 was found to minimize the ghosting artifacts in vivo human brain images, and maximize displacement in the focal spot of ex vivo porcine brain, while keeping ultrasound energy minimal.