Disclosed herein are example embodiments of devices, systems, and methods for mechanical fractionation of biological tissue using magnetic resonance imaging (MRI) feedback control. The examples may involve displaying an image representing first MRI data corresponding to biological tissue, and receiving input identifying one or more target regions of the biological tissue to be mechanically fractionated via exposure to first ultrasound waves. The examples may further involve applying the first ultrasound waves and, contemporaneous to or after applying the first ultrasound waves, acquiring second MRI data corresponding to the biological tissue. The examples may also involve determining, based on the second MRI data, one or more second parameters for applying second ultrasound waves to the biological tissue, and applying the second ultrasound waves to the biological tissue according to the one or more second parameters.