Abstract: An magnetic resonance apparatus in embodiments of the invention may include one or more of the following features: (a) a coil having at least two sections, (b) the at least two sections having a resonant circuit, (c) the at least two sections being reactively coupled or decoupled, (d) the at least two sections being separable, (e) the coil having openings allowing a subject to see or hear and to be accessed through the coil, (f) a cushioned head restraint, and (g) a subject input/output device providing visual data to the subject, the input/output device being selected from the group consisting of mirrors, prisms, video monitors, LCD devices, and optical motion trackers.

Abstract: This document discusses, among other things, a system and method for a coil having a plurality of resonant elements capable of radiofrequency transmission, reception, or both transmission and reception. One example includes a receive-only coil disposed within a transmit-only coil. Adjacent resonant elements are decoupled from one another by both capacitive elements and by the geometric configuration of the elements. Cables are coupled to each resonant element and are gathered at a junction in a particular manner.

Abstract: This document discusses, among other things, a system and method for a coil having a plurality of resonant elements capable of radiofrequency transmission, reception, or both transmission and reception. One example includes a multi-channel receive-only coil comprised of overlapping planar loops. Adjacent resonant elements are decoupled from one another by both capacitive elements and by the geometric configuration of the elements. Cables are coupled to each resonant element and are gathered at a junction in a particular manner.

Abstract: An magnetic resonance apparatus in embodiments of the invention may include one or more of the following features: (a) a coil having at least two sections, (b) the at least two sections having a resonant circuit, (c) the at least two sections being reactively coupled or decoupled, (d) the at least two sections being separable, (e) the coil having openings allowing a subject to see or hear and to be accessed through the coil, (f) a cushioned head restraint, and (g) a subject input/output device providing visual data to the subject, the input/output device being selected from the group consisting of mirrors, prisms, video monitors, LCD devices, and optical motion trackers.

Abstract: Self-shielded gradient coils are used to eliminate interactions between gradient coils and external structure. Interactions between gradient coils for different gradient axes are controlled by means of a balanced interconnection within each separate gradient coil set. One or both of the inner and outer coils within a gradient coil set are split such that for any localized capacitive current flow between coil sets there will be an equal and opposite current flow somewhere else between the coil sets.

Abstract: A method is provided for reducing acoustical noise generated when gradient coils which are part of a nuclear magnetic resonance (MR) scanner are energized by current pulses in the course of an MR study. The acoustical noise is due to vibrations of a fiber-glass coil form on which the coils are wound. The vibrations are excited by high frequency components in the squared-edged conventional current pulses. Significant noise reduction is achieved by shaping the leading and trailing current pulse edges to eliminate the objectionable high frequency components. Advantageously, the pulse edges can be shaped using sinusoidal and Bessel function waveforms. Another useful waveform for pulse shaping is a ramp function with rounded transition points.

Abstract: A circuit for detecting the position of a radio frequency (RF) coil assembly in a magnetic resonance (MR) scanner includes, in the preferred embodiment, a normally closed switch connected to ground in parallel with a PIN diode which forms part of a transmit/receive (T/R) switch used to selectively couple the RF coil assembly to an RF power amplifier and an RF receiver preamplifier. The switch is operable by an actuating rod mounted to the RF coil assembly structure, whose position is to be sensed, such that when the assembly is in place the switch contacts are closed, and open when the assembly is not in place. The opening and closing of the switch shunts the PIN diode in and out, respectively, of the T/R switch circuit, thereby changing the voltage drop across other PIN diodes in the circuit. This change is sensed by a comparator circuit, the output of which is indicative of the RF coil assembly position.