Abstract: Certain implementations of the disclosed technology may include active marker devices, retrofits, systems, and methods for determining the position of interventional devices under MRI. A marker device is provided that utilizes an optical fiber, an acousto-optical sensor region that includes an electro-mechanical conversion assembly, and one or more antenna(e) The one or more antennae are configured to receive MRI radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal corresponding to the position. The acousto-optical sensor region may include a resonator and may be modulated by acoustic waves generated responsive to the electrical signal received from the one or more antennae The acousto-optical sensor region may be interrogated by light via the optical fiber to determine the position of the device for providing an active marker in the MRI image.

Abstract: Methods are disclosed herein for measuring local E-fields, B-fields, and/or temperature effects of an MRI scan utilizing an acousto-optical sensor. A method includes positioning the acousto-optical sensor at a location of a body or phantom; receiving, with an antenna of the acousto-optical sensor, MRI RF energy localized at the first location; interrogating, with a light source, and via an optical fiber, an acousto-optical sensor region of the acousto-optical sensor; detecting, with a photodetector, interrogation light reflected from the acousto-optical sensor region; and outputting one or more signals corresponding to the detected interrogation light reflected from the acousto-optical sensor region. The one or more signals can correspond to an E-field, a B-field, and/or a temperature of the received MRI RF energy at the first location. Additional methods can include mapping results of multiple measurements around an implant.

Abstract: Certain implementations of the disclosed technology may include active marker devices, retrofits, systems, and methods for determining the position of interventional devices under MRI. A marker device is provided that utilizes an optical fiber, an acousto-optical sensor region that includes an electro-mechanical conversion assembly, and one or more antenna(e). The one or more antennae are configured to receive MRI radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal corresponding to the position. The acousto-optical sensor region may include a resonator and may be modulated by acoustic waves generated responsive to the electrical signal received from the one or more antennae. The acousto-optical sensor region may be interrogated by light via the optical fiber to determine the position of the device for providing an active marker in the MRI image.