Abstract: A nuclear magnetic resonance radio frequency coil. The disclosed coil provides high frequency resonance signals for perturbing a magnetic field within the coil. The coil is impedance matched and tuned with adjustable capacitors. A balanced configuration is achieved with a co-axial cable chosen to phase shift an energization signal coupled to the coil. The preferred coil is a thin metallic foil having a shorting conductor, four wing conductors, and uniquely shaped parallel cross conductors connecting the shorting and wing conductors. When mounted to an rf transmissive plastic substrate and energized the coil produces a homogenous field within a region of interest the size of a patient head. A semicircular balanced feedbar arrangement is used to minimize undesired field contributions.

Abstract: A resonance exciting coil (C) excites magnetic resonance in nuclei disposed in an image region in which a main magnetic field and transverse gradients have been produced. A flexible receiving coil (D) includes a flexible plastic sheet (40) on which one or more loops (20) are adhered to receive signals from the resonating nuclei. Velcro straps (46) strap the flexible sheet and the attached coil into close conformity with the surface of the portion of the patient to be imaged. An impedance matching or coil resonant frequency adjusting network (50) is mounted on the flexible sheet for selectively adjusting at least one of an impedance match and the peak sensitivity resonant frequency of the receiving coil. A preamplifier (52) amplifies the received signals prior to transmission on a cable (24). A selectively variable voltage source (70) applies a selectively adjustable DC bias voltage to the cable for selectively adjusting at least one of the impedance match and the LC resonant frequency of the receiving coil.

Abstract: An incomplete set of magnetic resonance image data is collected and stored in a view memory (40). The incomplete set of image data includes a central or first set of data values (42, 42') and a side or second set of data values (44, 44'). The central data set is operated on by a roll-off filter (64) and a Fourier transform (66) to create a normalized phase map (72). The first and second data sets are Fourier transformed (82) and phase corrected (86) by being multiplied with a complex conjugate (88) of the corresponding phase map data value. A third data set (46, 46') is generated (90) by determining the complex conjugate of the second or side data set. The third data set is Fourier transformed (94) and multiplied (98) by a corresponding value from the phase map to produce a second phase corrected image representation. The first and second phase corrected image representations are summed (100) and stored in a resultant image memory (102).

Abstract: The magnetic resonance signals in a magnetic resonance imaging apparatus are detected by a surface or localized coil assembly (D). To improve the field homogeneity and increase the signal-to-noise ratio when examining a region of interest deep within a subject, the surface coil assembly is configured with a first coil portion (22) and a second coil portion (24). The first coil portion is disposed along an exterior surface of the subject. The second coil portion is disposed parallel to the first coil portion and displaced outward a distance (44) from the first coil portion and the subject exterior surface. The first and second coil portions are electrically interconnected with an opposite current phase in a dipole pair such that the second current portion reduces the sensitivity of the first coil portion to magnetic resonance signals originating close to the surface of the subject.

Abstract: A resonator coil assembly (32) includes a dielectric sleeve (40) on which a first resonator coil portion (42) and a second resonator coil portion (44), each of copper foil, are adhered. The dielectric sleeve is dimensioned to receive a human torso therein and in one embodiment (FIG. 1) is circular in cross section and in another (FIG. 4) is elliptical in cross section. A pair of adjustable tuning capacitances (64, 66) and a pair of adjustable matching capacitances (68, 70) are interconnected between one end of the each coil portion and a metal bore liner (54). An opposite end of the coil portions are capacitively coupled to each other (FIG. 1) or to the bore liner (FIG. 3). A half wave length cable (72) interconnects the junctions between the first and second tuning and matching capacitances. One of these junctions is connected by a cable (74) with a radio frequency generator (30) and a radio receiver (34).

Abstract: A magnetic field control (A) causes a magnetic field through an imaging region of a magnetic resonance spectrometer. A radio frequency generator (20) generates radio frequency signals which are transmitted on a transmission line (22) to a probe coil (C). Magnetic resonance signals received by the probe coil (C) are conveyed over the transmission line to a radio frequency receiver (24) for reconstruction into a magnetic resonance image. An inductive matching network (D) is connected between the probe coil and the transmission line for matching the resistive impedance of the coil with the resistive impedance of the transmission line and for resonating the coil at a frequency other than its self resonance frequency. When the probe coil is operated above the self resonance frequency, it is capacitively reactive. An inductor (40) is connected across coil feed points (30, 32) of the probe coil.

Abstract: A portion of a subject (22) which is undergoing respiratory or other motion is disposed in an image region (20) to be examined. A respiratory or other motion monitor (50) monitors the cyclic respiratory motion and provides output signals indicative of chest expansion. A phase encoding gradient selector (60) selects the phase encoding gradient that is to be applied by a gradient magnetic field controller (40) and coil (42). A central phase encoding gradient is selected corresponding to a chest relaxation extreme and minimum and maximum phase encoding gradients are selected corresponding to a chest expansion extreme (FIG. 2). Intermediate degrees of monitored physical movement cause the selection of corresponding intermediate phase encoding gradients. Resonance signals collected during each phase encoding gradient are Fourier or otherwise transformed (80) into a corresponding view.

Abstract: A shimming magnetic field control (22) causes shimming magnetic fields for improving uniformity of a main magnetic field generated by main magnets (10). A resonance excitation control (32) selectively applies a resonance excitation pulse (34) and inversion pulse (36) for inverting the spin magnetization of water and lipid dipoles. A phase sensitive detector (30) selectively receives resonance signal components which are transformed by a transform algorithm (70) into a real image (72) and an imaginary image (74). The inversion pulse (36) is shifted by a time such that the water and lipid spin magnetizations are out of phase by a predetermined amount. With a 90.degree. phase difference, the real image represents water and the imaginary represents lipid. A phase image (80) is derived from a reference image pair (76, 78). A phase unwrap circuit (82) removes ambiguities attributable to the spin magnetizations becoming dephased by multiples of 2.pi. to create a phase map (84).

Abstract: A nuclear magnetic resonance radio frequency coil. The disclosed coil provides high frequency resonance signals for perturbing a magnetic field within the coil. The coil is impedance matched and tuned with adjustable capacitors. A balanced configuration is achieved with a co-axial cable chosen to phase shift an energization signal coupled to the coil. The preferred coil is a thin metallic foil having a shorting conductor, four wing conductors, and uniquely shaped parallel cross conductors connecting the shorting and wing conductors. When mounted to a rf transmissive plastic substrate and energized the coil produces a homogeneous field within a region of interest the size of a patient head. A semicircular balanced feedbar arrangement is used to minimize undesired field contributions.

Abstract: This invention has to do with a stock indicator which includes a strip that will take writing and erasure and which includes printed legends such as "Part No.", "Quantity" and "Date", each associated with blanks to be filled in by pen, pencil or crayon. Such a strip may be designed to provide a counter dial or dials, or may be associated with a separate strip or strips which provide a readily readable dial or dials. Associated with each such dial is a rotary indicator member manually operable step by step in one direction as associated items are withdrawn, and in the opposite direction when items are added or replaced. Indicator devices of this nature may be made at very small cost, and each can be permanently associated with a particular shelf section or bin, or transferred from one stock collection to another if reorganization is required.