Tracking system to monitor the position and orientation of a device using magnetic resonance detection of a sample contained within the device

A method for tracking a location of an invasive device within a subject employing magnetic resonance (MR) comprising the steps of:

• a) attaching a MR active sample to said invasive device;
• b) applying a homogeneous magnetic field having substantially uniform amplitude over said subject;
• c) transmitting radiofrequency (rf) energy of a selected duration, amplitude and frequency into the MR active sample and said subject to cause nutation of a selected ensemble of spins in said subject and the MR active sample;
• d) varying the amplitude of the magnetic field in at least one spatial dimension over time causing the ensemble of spins within the MR active sample to emit an MR response signal;
• e) detecting the emitted MR response signal from the MR active sample;
• f) processing the detected MR response signal;
• g) calculating a location of the MR active sample and said invasive device from the processed MR response signal;
• and
• h) displaying the location of said invasive device to an operator.

A magnetic resonance (MR) tracking system comprising:

• a) an invasive device adapted to be inserted into a subject;
• b) an MR active sample incorporated into the invasive device;
• c) static magnetic field means adapted for applying a homogeneous magnetic field having substantially uniform amplitude over the subject;
• d) radiofrequency (rf) transmitter means attached to the invasive device adapted for transmitting rf energy of a selected duration, amplitude and frequency into the subject and the MR active sample to cause nutation of a selected ensemble of spins within the subject and the MR active sample;
• e) gradient means adapted for varying the amplitude of the magnetic field in at least one spatial dimension over the subject and the MR active sample over time;
• f) detection means adapted for detecting an MR response signal from the selected ensemble of spins;
• g) calculation means adapted for calculating a location of the invasive device from the detected MR response signal;
• h) controller connected to the rf transmitter means, the detection means, the calculation means and the gradient means adapted for activating the rf transmitter means, the detection means, the calculation means and the gradient means according to a desired MR sequence;
• and
• i) display means connected to the calculation means adapted for displaying the location of the invasive device to an operator.