Active Adaptive Detuning Systems to Improve Safety of Interventional Devices

The invention offered for licensing and commercial development is in the field of Interventional Magnetic Resonance Imaging (“iMRI”). More specifically the invention discloses interventional devices in which the heat generated at the device during the imaging process can be controlled to not exceed acceptable levels.

Active MRI compatible intravascular devices contain RF antenna to so that they are visible under MRI. However, these metallic structures may heat up significantly during interventional MRI procedures due to eddy current formation over the conductive transmission lines. The electrical field coupling between interventional devices and RF transmission coils strongly depend on the device position and orientation within the bore and insertion length of the device. Currently, conventional detuning circuit is used to decouple the conductive intravascular device during RF transmission phase of the MRI by activating the circuit with a PIN diode. However, conventional passive techniques do not adapt for each possible orientation or insertion length of the device. The current invention provides for a new active detuning system that adapts its circuit component to limit heating for every possible orientation and insertion length. The system reads out the received current signal value during RF transmission phase and changes the decoupling capacitor value by using varactor and integrated circuit components to reach new resonant condition (very high impedance).