Acousto-optical active markers for interventional MRI

A system for active magnetic resonance imaging (MRI) device location visualization comprising:

• a non-conductive optical fiber with a distal end, a proximal end, and an acousto-optical sensor region disposed in proximity to the distal end and comprising a first fiber Bragg grating (FBG);
• and
• an electro-mechanical conversion assembly comprising:
• a first antenna configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• and
• a first piezoelectric transducer in mechanical communication with the first FBG, and in electrical communication with the first antenna;
• wherein the first piezoelectric transducer is configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the first antenna;
• and
• wherein at least a thickness dimension of the first piezoelectric transducer is configured to produce one or more resonance frequencies corresponding with one or more Larmor frequencies;
• wherein characteristics of the modulated elastic properties of the optical fiber are detectable at the proximal end of the optical fiber;
• and
• wherein at least the optical fiber and the electro-mechanical conversion assembly are configured to reduce MRI RF-induced heating of the system.

A system for active magnetic resonance imaging (MRI) device location visualization comprising:

• a non-conductive optical fiber with a distal end, a proximal end, and an acousto-optical sensor region disposed in proximity to the distal end and comprising a first fiber Bragg grating (FBG) and a second FBG;
• and
• an electro-mechanical conversion assembly comprising:
• a first antenna configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• a second antenna oriented in an orthogonal direction with respect to the first antenna:
• a first piezoelectric transducer in mechanical communication with the first FBG, and in electrical communication with the first antenna;
• and
• a second piezoelectric transducer in mechanical communication with the second FBG and in electrical communication with the second antenna;
• wherein the first piezoelectric transducer is configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the first antenna;
• wherein characteristics of the modulated elastic properties of the optical fiber are detectable at the proximal end of the optical fiber;
• and
• wherein at least the optical fiber and the electro-mechanical conversion assembly are configured to reduce MRI RF-induced heating of the system.

A catheter retrofit system for magnetic resonance imaging (MRI) active device location visualization, the system comprising:

• a retrofitted interventional probe comprising:
• a mounting tube configured to accept a catheter and to a least partially conform to a shape of the catheter;
• an optical fiber including a distal end in communication with a portion of the mounting tube;
• and
• an acousto-optical sensor region disposed at the distal end of the optical fiber, the acousto-optical sensor region including an electro-mechanical conversion assembly comprising:
• one or more antennae disposed on the mounting tube and configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• and
• a radial mode resonator in mechanical communication with the acousto-optical sensor region, wherein the radial mode resonator is in electrical communication with one or more of the antennae, wherein the radial mode resonator is configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the one or more antennae, and wherein at least a thickness dimension of the radial mode resonator is configured to produce one or more resonance frequencies corresponding with one or more Larmor frequencies;
• and
• a mechanical-optical conversion assembly in communication with a proximal end of the optical fiber, the mechanical-optical conversion assembly including:
• a light source coupled to the proximal end of the optical fiber and configured to interrogate the acousto-optical sensor region;
• and
• a photodetector coupled to the proximal end of the optical fiber, the photodetector configured to receive interrogation light reflected from the acousto-optical sensor region.

A catheter retrofit system for magnetic resonance imaging (MRI) active device location visualization, the system comprising:

• a retrofitted interventional probe comprising:
• a mounting tube configured to accept a catheter and to a least partially conform to a shape of the catheter;
• an optical fiber including a distal end in communication with a portion of the mounting tube;
• and
• an acousto-optical sensor region disposed at the distal end of the optical fiber and comprising a first fiber Bragg grating (FBG) and a second FBG;
• wherein the acousto-optical sensor region includes an electro-mechanical conversion assembly comprising:
• a first antenna and a second antenna, each disposed on the mounting tube and configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• a first piezoelectric transducer in mechanical communication with the first FBG and in electrical communication with the first antenna;
• and
• a second piezoelectric transducer in mechanical communication with the second FBG and in electrical communication with the second antenna;
• wherein the first and second piezoelectric transducers are configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the first and second antennae;
• and
• a mechanical-optical conversion assembly in communication with a proximal end of the optical fiber, the mechanical-optical conversion assembly including:
• a light source coupled to the proximal end of the optical fiber and configured to interrogate the acousto-optical sensor region;
• and
• a photodetector coupled to the proximal end of the optical fiber, the photodetector configured to receive interrogation light reflected from the acousto-optical sensor region.

A marker device for active magnetic resonance imaging (MRI) device location visualization, the marker device comprising:

• a system comprising:
• a non-conductive optical fiber with a distal end, a proximal end, and an acousto-optical sensor region disposed in proximity to the distal end and comprising a first fiber Bragg grating (FBG);
• and
• an electro-mechanical conversion assembly comprising:
• a first antenna configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• and
• a first piezoelectric transducer in mechanical communication with the first FBG, and in electrical communication with the first antenna;
• wherein the first piezoelectric transducer is configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the first antenna:
• wherein characteristics of the modulated elastic properties of the optical fiber are detectable at the proximal end of the optical fiber;
• and
• wherein at least the optical fiber and the electro-mechanical conversion assembly are configured to reduce MRI RF-induced heating of the system;
• and
• a resonator in communication with the optical fiber;
• wherein the resonator is configured to:
• enhance a modulation amplitude of the acousto-optical sensor region;
• and
• at least partially reflect the generated acoustic waves to enhance a modulation amplitude of the acousto-optical sensor region;
• and
• wherein the resonator comprises an acoustical discontinuity comprising one or more of:
• a notch formed by removal of at least a portion of cladding from the optical fiber;
• or
• deposition of a material on the optical fiber.

A marker device for active magnetic resonance imaging (MRI) device location visualization, the marker device comprising:

• a system comprising:
• a non-conductive optical fiber with a distal end, a proximal end, and an acousto-optical sensor region disposed in proximity to the distal end and comprising a first fiber Bragg grating (FBG);
• and
• an electro-mechanical conversion assembly comprising:
• a first antenna configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• and
• a first piezoelectric transducer in mechanical communication with the first FBG, and in electrical communication with the first antenna;
• wherein the first piezoelectric transducer is configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the first antenna:
• wherein characteristics of the modulated elastic properties of the optical fiber are detectable at the proximal end of the optical fiber;
• and
• wherein at least the optical fiber and the electro-mechanical conversion assembly are configured to reduce MRI RF-induced heating of the system;
• and
• a resonator in communication with the optical fiber and configured to enhance a modulation amplitude of the acousto-optical sensor region;
• wherein the resonator comprises a radial mode resonator in communication with the acousto-optical sensor region of the optical fiber;
• and
• wherein at least a thickness dimension of the radial mode resonator is configured to produce one or more resonance frequencies corresponding with one or more Larmor frequencies.

A catheter retrofit device comprising:

• a mounting tube configured to accept a catheter and to a least partially conform to a shape of the catheter;
• an optical fiber including a distal end in communication with at least a portion of the mounting tube;
• and
• an acousto-optical sensor region disposed at the distal end of the optical fiber comprising:
• a first fiber Bragg grating (FBG);
• a second FBG;
• a first antenna;
• a second antenna;
• a first piezoelectric transducer in mechanical communication with the first FBG and in electrical communication with the first antenna;
• and
• a second piezoelectric transducer in mechanical communication with the second FBG and in electrical communication with the second antenna.

A catheter retrofit device for active magnetic resonance imaging (MRI) device location visualization, the retrofit device comprising:

• a mounting tube configured to accept a catheter and to a least partially conform to a shape of the catheter;
• an optical fiber including a distal end in communication with a portion of the mounting tube
• a resonator in communication with the optical fiber;
• and
• an acousto-optical sensor region disposed at the distal end of the optical fiber, the acousto-optical sensor region including an electro-mechanical conversion assembly comprising:
• one or more antennae disposed on the mounting tube and configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• and
• an ultrasonic transducer in mechanical communication with the acousto-optical sensor region, and in electrical communication with one or more of the antennae, the ultrasonic transducer configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from one or more of the antennae;
• wherein the resonator is configured to at least partially reflect the generated acoustic waves for enhanced modulation of the acousto-optical sensor region;
• and
• wherein the resonator comprises an acoustical discontinuity comprising a notch formed by removal of at least a portion of cladding from the optical fiber.

A catheter retrofit device for active magnetic resonance imaging (MRI) device location visualization, the retrofit device comprising:

• a mounting tube configured to accept a catheter and to a least partially conform to a shape of the catheter;
• an optical fiber including a distal end in communication with a portion of the mounting tube;
• a radial mode resonator;
• and
• an acousto-optical sensor region disposed at the distal end of the optical fiber, the acousto-optical sensor region including an electro-mechanical conversion assembly comprising:
• one or more antennae disposed on the mounting tube and configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• and
• an ultrasonic transducer in mechanical communication with the acousto-optical sensor region, and in electrical communication with one or more of the antennae, the ultrasonic transducer configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from one or more of the antennae;
• wherein the radial mode resonator is in communication with the acousto -optical sensor region of the optical fiber;
• and
• wherein at least a thickness dimension of the radial mode resonator is configured to produce one or more resonance frequencies corresponding with one or more Larmor frequencies.

A catheter retrofit device for active magnetic resonance imaging (MRI) device location visualization, the retrofit device comprising:

• a mounting tube configured to accept a catheter and to a least partially conform to a shape of the catheter;
• an optical fiber including a distal end in communication with a portion of the mounting tube;
• and
• an acousto-optical sensor region disposed at the distal end of the optical fiber and comprising a first fiber Bragg grating (FBG) and a second FBG;
• wherein the acousto-optical sensor region includes an electro-mechanical conversion assembly comprising:
• a first antenna and a second antenna, each disposed on the mounting tube and configured to receive radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal;
• a first piezoelectric transducer in mechanical communication with the first FBG and in electrical communication with the first antenna;
• and
• a second piezoelectric transducer in mechanical communication with the second FBG and in electrical communication with the second antenna;
• wherein the first and second piezoelectric transducers are configured to modulate elastic properties of the acousto-optical sensor region with acoustic waves generated responsive to the electrical signal received from the first and second antennae.