Picker International, Inc.

Theodore J Reisker

David A Molyneaux

G Neil Holland

Mark A Richard

Douglas M Blakeley

William O Braum

Benjamin R Stern

John T Carlon

An endocavity RF coil assembly for an MRI apparatus includes a reusable probe (30). The reusable probe has a hollow outer cover (60) having a closed distal end and (62) an open proximate end (64). The distal end (62) is formed to fit into a cavity of a subject being examined. An active RF coil element (72) is rigidly formed about an internal sleeve (70) which is located within the distal end (62) of the outer cover (60). A tuning and matching circuit is disposed within the outer cover (60) on the proximate end (64) side of the active RF coil element (72). The tuning and matching circuit is arranged on a printed circuit board (74) and attached to the active RF coil element (72). An over-molded form (90) is connected to the proximate end (64) of the outer cover (60). The over-molded form (90) is arranged such that it seals the proximate end (64) of the outer cover (60) closed.

MRI endocavitary coils and decontamination

A magnetic resonance imaging apparatus includes a main magnet (12) for generating a main magnetic field in an examination region (14) and a radio frequency coil assembly. The radio frequency coil assembly transmits radio frequency pulses into the examination region (14) to induce magnetic resonance in selected dipoles disposed therein. The radio frequency coil assembly also receives signals from selected resonating dipoles. The radio frequency coil assembly includes a birdcage coil (60) having a plurality of conductive elements (64) constructed on a dielectric form positioned about the examination region (14). The birdcage coil (60) includes a plurality of capacitors (C1-C24) and corresponding plurality of series connected diode inductor pairs connected in parallel with each capacitor to form resonant trap circuits. The radio frequency coil assembly also includes at least one focus coil (62a-c) having a conductive loop placed on a thin dielectric layer attached to the birdcage coil (60) such that the focus coil (62a-c) is electrically insulated from the birdcage coil (60). The focus coil includes a plurality of capacitors connected in series and corresponding plurality of series connected diode inductor pairs connected in parallel with each capacitor.

Volume RF coils with integrated high resolution focus coils for magnetic

A cardiac electrode (40) has a plug (48) which is frictionally received in a socket (50) of an electrical lead (56). An impedance (54) is connected in series between the electrical lead and the socket to pass ECG signals substantially unattenuated and for blocking radio frequency signals induced in the lead from reaching the socket and the electrode and heating the electrode to a sufficient temperature to burn the patient. The impedance includes an LC circuit (66, 68) which freely passes low frequency signals, such as cardiac signals, but which is tuned to resonance at radio frequencies, particularly at the frequency of resonance excitation and manipulation pulses of a magnetic resonance imager (A). Alternately, the impedance may include a resistive element for blocking the induced currents. A temperature sensor (60) is mounted in intimate contact with an electrically and thermally conductive socket portion (52) to sense the temperature of the electrode, indirectly. A temperature sensor lead (62), the cardiac lead (56), and a respiratory or other anatomical condition sensor are connected with a multiplexing means (140) which cyclically connects the output signals thereof with an analog to digital converter (142). The digital signals are converted to digital optical signals (102) to be conveyed along a light path (104) out of the examination region. The bits of the received digital signal are sorted (144) between an R-wave detector (120), a temperature limit check (122) which checks whether the temperature of the electrode exceeds preselected limits, and a respiratory detector (132).

Temperature sensing and control system for cardiac monitoring electrodes

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Willoughby Hills, OH, United States of America

Theodore J Reisker