Abstract: A coil for creating improved homogeneity in magnetic flux density in a radio frequency resonator for magnetic resonance imaging and spectroscopy of the human head. The coil has a plurality of conductive members. Each of the conductive members has a linear portion and a tapered portion. The conductive members are arranged to form a first opening having a first diameter and a second opening having a second diameter, with the second diameter being different from the first diameter. The tapered portions of the conductive members provide the coil with a substantially homogeneous pattern of magnetic flux density in at least one of three orthogonal imaging planes of the coil.

Abstract: A method for creating improved homogeneity in magnetic flux density in a radio frequency resonator for magnetic resonance imaging and spectroscopy of the human head. A tapered birdcage resonator is also provided. The tapered birdcage resonator includes two electrically conductive rings and a plurality of rods or conductor legs. The first electrically conductive ring forms an inferior end of the coil. The plurality of legs extends from the first electrically conductive ring. Each of the plurality of legs has a linear portion and a tapered portion. The second electrically conductive ring forms a superior end of the coil and is connected to the tapered portion of the plurality of legs.

Abstract: A method for creating improved homogeneity in magnetic flux density in a radio frequency resonator for magnetic resonance imaging and spectroscopy of the human head. A tapered birdcage resonator is also provided. The tapered birdcage resonator includes two electrically conductive rings and a plurality of rods or conductor legs. The first electrically conductive ring forms an inferior end of the coil. The plurality of legs extends from the first electrically conductive ring. Each of the plurality of legs has a linear portion and a tapered portion. The second electrically conductive ring forms a superior end of the coil and is connected to the tapered portion of the plurality of legs.

Abstract: 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.

Abstract: 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.

Abstract: 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.