MRI compatible pulse oximetry system

A pulse oximeter apparatus in conjunction with a magnetic resonance apparatus disposed in a shielded room, the magnetic resonance imaging apparatus including:

• a bore liner which defines a patient receiving region;
• a vacuum dewar connected with the bore liner;
• a magnet assembly disposed in the vacuum dewar for generating magnetic fields through the patient receiving region;
• an RF coil means disposed adjacent the bore liner for transmitting and receiving radio frequency signals into and from the patient receiving region;
• the pulse oximeter apparatus comprising:
• a pulse oximetry sensor unit with an electrical lead disposed in the bore liner;
• a preamplifier grounded to the vacuum dewar and surrounded by a shield connected with the vacuum dewar, the preamplifier being connected with the sensor unit lead for amplifying electrical signals from the sensor unit;
• a processing and display means disposed exterior to the shielded room and connected with the preamplifier for processing electrical signals therefrom to generate a display of at least patient pulse and blood oxygen concentration.

A pulse oximetry apparatus comprising:

• a sensor unit means for sensing characteristics of a patient's blood;
• an electrical lead connected with the sensor unit means for supplying electrical power thereto and conveying electrical signals indicative of the blood characteristics;
• an electrical plug connected with the lead;
• an electrical socket releasably interconnected with the plug, the socket being adapted for mounting within a patient receiving bore of a magnetic resonance apparatus;
• a preamplifier connected with the socket for amplifying the electrical signals indicative of the blood characteristics;
• a filter means disposed between the sensor unit means and the preamplifier for presenting a high impedance to radio frequency signals in a selected range;
• a processing and display means for processing the electrical signals indicative of the blood characteristics from the preamplifier to derive a display of pulse and blood oxygen concentration of a patient who is sensed by the sensing unit means, the processing and display means including a radio frequency clock;
• a radio frequency filter disposed between the preamplifier and the processing and display means for preventing radio frequency signals from the clock from being conveyed to the preamplifier and for preventing radio frequency signals from being conveyed from the preamplifier to the processing and display means.

A magnetic resonance imaging apparatus comprising:

• a bore liner which defines a patient receiving region therein;
• a magnet assembly for generating a strong, substantially uniform magnetic field through the patient receiving region defined within the bore liner;
• a gradient coil assembly disposed adjacent the patient receiving region for inducing magnetic field gradients across the magnetic field;
• an RF coil means for transmitting radio frequency signals into and receiving radio frequency signals from the patient receiving region;
• a pulse oximeter including:
• a pulse oximetry sensor unit for sensing patient pulse and blood oxygen characteristics and generating electrical signals indicative thereof on a connected electrical lead disposed in the bore liner;
• a preamplifier grounded to the magnet assembly and surrounded by a shield connected with the magnet assembly, the preamplifier being connected with the sensor unit electrical lead for amplifying the electrical signals from the sensor unit;
• a processing and display means connected with the preamplifier for processing the amplified electrical signals therefrom to generate a display indicative of at least patient pulse and blood oxygen concentration.

A combined magnetic resonance and pulse oximetry sensing apparatus comprising:

• a bore liner for defining a patient receiving region;
• a magnetic resonance means for inducing magnetic resonance in and receiving magnetic resonance signals from at least a selected region of a patient disposed within the bore liner;
• a socket mounted in the bore liner detachably receiving a plug on the end of a lead connected with a pulse oximetry sensor unit;
• a preamplifier connected with the socket for amplifying electrical signals from the sensor unit;
• a processing and display means connected with the preamplifier for processing electrical signals therefrom to generate a display of at least patient blood oxygen concentration.