Abstract: A novel MRI-compatible amplifier design uses positive feedback from a low-noise Field-Effect Transistor to amplify the signal current within a resonant NMR coil. The amplified signal current in this low-power circuit produces RF flux can be coupled out to receiving loops positioned externally without significant loss in sensitivity. In other aspects, the amplifier may be remotely powered by external resonant loops, a small non-magnetic battery, or optical power, such that the NMR coil can be positioned during highly invasive procedures such as for surgical resection of tumors in deep-lying tissues to develop high-resolution images.

Abstract: A novel MRI-compatible amplifier design uses positive feedback from a low-noise Field-Effect Transistor to amplify the signal current within a resonant NMR coil. The amplified signal current in this low-power circuit produces RF flux can be coupled out to receiving loops positioned externally without significant loss in sensitivity. In other aspects, the amplifier may be remotely powered by external resonant loops, a small non-magnetic battery, or optical power, such that the NMR coil can be positioned during highly invasive procedures such as for surgical resection of tumors in deep-lying tissues to develop high-resolution images.

Abstract: A MRI RF coil array is formed from a first coil having a null B1 point and a quasi-one-peak sensitivity profile, and a second coil oriented with respect to the first coil to reduce coupling.

Abstract: A magnetic resonance imaging (MRI) array coil system and method for breast imaging are provided. The MRI array coil system includes a top coil portion with two openings configured to receive therethrough objects to be imaged. The MRI array coil system further includes a bottom coil portion having two openings configured to access from sides of the bottom coil portion the objects to be imaged. The top coil portion and bottom coil portion each have a plurality of coil elements configured to provide parallel imaging.

Abstract: A partially parallel acquisition RF coil array for imaging a sample includes at least a first, a second and a third coil adapted to be arranged circumambiently about the sample and to provide both contrast data and spatial phase encoding data.

Abstract: A MRI array coil includes a plurality of first coils in a receive coil array and a plurality of second coils in a transmit coil array. The receive coil array and the transmit coil array are electrically disjoint.

Abstract: A partially parallel acquisition RF coil array for imaging a human head includes at least a first, a second and a third loop coil adapted to be arranged circumambiently about the lower portion of the head; and at least a forth, a fifth and a sixth coil adapted to be conformably arranged about the summit of the head. A partially parallel acquisition RF coil array for imaging a human head includes at least a first, a second, a third and a fourth loop coil adapted to be arranged circumambiently about the lower portion of the head; and at least a first and a second Figure-8 or saddle coil adapted to be conformably arranged about the summit of the head.

Abstract: A partially parallel acquisition RF coil array for imaging a human head having a summit and a lower portion includes at least a first, a second and a third quadrature coil pair adapted to be arranged circumambiently about the lower portion of the head; and at least a forth, a fifth and a sixth quadrature coil pair adapted to be conformably arranged about the summit of the head.

Abstract: A magnetic resonance imaging (MRI) array coil system and method for breast imaging are provided. The MRI array coil system includes a top coil portion with two openings configured to receive therethrough objects to be imaged. The MRI array coil system further includes a bottom coil portion having two openings configured to access from sides of the bottom coil portion the objects to be imaged. The top coil portion and bottom coil portion each have a plurality of coil elements configured to provide parallel imaging.

Abstract: A MRI coil having an axis and a first end and an opposite second end with respect to said axis includes a first ring element at the first end, a second ring element, a third ring element, a fourth ring element at the second end where the first ring element encompasses a smaller area than each of the second, third, and fourth ring elements. The coil also includes a plurality of axial elements connected between the first, second, third and fourth ring elements. The third and fourth ring elements are axially closer than the first and second ring elements.

Abstract: A MRI gradient coil set includes a uniplanar Z-gradient coil, a biplanar X-gradient coil, and a biplanar Y-gradient coil. The coil set provides an open Z-axis face.

Abstract: An RF resonator mounted on a dielectric support is operated in quadrature at a selected NMR frequency. The resonator consists of four axially distributed high frequency ring current paths on the support and at least four high frequency current paths interconnect each pair of adjacent ring paths. In the preferred embodiment at least sixteen equally spaced parallel segments connect each ring pair and are aligned with one another. The ring segments between the parallel segments together with the parallel segments form loops. At least one discrete capacitor is placed in each outer current loop thereby interrupting the loop. However, this is done so that no inner loop is interrupted by a capacitor. By using quadrature input/output coupling, either inductive or capacitive, a co-rotating mode is excited in the two outer loops through the inner loops providing a highly uniform field across the resonator.

Abstract: A radio frequency volume resonator mounted on a generally cylindrical dielectric support can be operated in quadrature at one or more NMR frequencies. The resonator consists of four axially distributed high frequency ring current paths and a dielectric support, at least four high frequency current paths interconnect each pair of adjacent ring paths, at least one discrete capacitor is placed in each current loop but arranged so that none of the ring current paths is interrupted by a capacitor.

Abstract: A radio frequency volume resonator mounted on a dielectric support can be operated in quadrature at one or more NMR frequencies. The resonator consists of four axially distributed high frequency ring current paths on the dielectric support. At least four high frequency current paths interconnect each pair of adjacent ring paths. The ring segments with interconnecting segments form loops. At least one discrete capacitor is placed in each loop.

Abstract: The discovery has been made that coil-to-ground parasitic losses substantially reduce the sensitivity of a nuclear magnetic resonance probe used in nuclear magnetic resonance analyses of lossy dielectic (i.e., relatively conductive) samples, such as biological tissue. A probe circuit is disclosed in which a balancing impedance is inserted for substantially reducing the influence of coil-to-ground parasitics. The probe circuit resulting from the insertion of the balancing impedance markedly increases sensitivity. Concomittantly, the quality factor of the probe circuit and the signal-to-noise ratio of nuclear magnetic resonance signals are substantially improved. The disclosed probe circuit can be incorporated in nuclear magnetic resonance analysis systems where the sample coil is either implanted or placed on the surface of a sample; where the sample coil forms a portion of a large-scale imaging system; or the sample coil is used in a traditional analytical mode with a sample contained in a glass tube.