Abstract: In one example, an antenna is disclosed comprising a first, outer conductor, at least one inner conductor within the first outer conductor, and a second outer conductor surrounding the first outer conductor. The second outer conductor may define a plurality of holes therethrough. The at least one inner conductor may comprise a plurality of inner conductors. At least two of the plurality of inner conductors may be connected to each other in series, across a capacitor. At least two of the plurality of inner conductors may be connected to each other in parallel, across a capacitor. The at least one inner conductor may be sufficiently surrounded by the first outer conductor to shield the inner conductor from receiving a radiofrequency signal.

Abstract: Antennas for use in magnetic resonance imaging (“MRI”) comprise a coaxial cable unit having an inner conductor tuned to a frequency, typically the Larmor frequency of the species of interest, and an outer conductor substantially surrounding the inner conductor and also tuned to the frequency. The inner and outer conductors are inductively coupled. The antennas may be used as receiving and transmitting antennas. In a receiving antenna, the inner conductor provides an output of the antenna. In a transmitting antenna, an input is provided to the inner conductor. Antenna arrays of one or more coaxial cable units, wherein the inner conductors of each unit are electrically connected and the outer conductors are electrically connected, and the units are inductively coupled, may be provided. Additional coaxial cable units may also be provided, inductively coupled to adjacent coaxial cable units. Each coaxial cable unit may comprise multiple inner conductors.

Abstract: An MRI antenna comprises an inner conductor with first and second ends and an outer conductor with first and second ends. The outer conductor substantially surrounds the inner conductor. The inner and outer conductors define a region for receiving a body part and the inner conductor is electrically connected to the outer conductor. The inner and outer conductors may be connected in a variety of manners. For example, the inner conductor may be directly electrically connected to the outer conductor. The inner conductor may also be connected electrically to the outer conductor through one or more capacitors. A magnetic resonance imaging system including the antenna of the present invention is also disclosed.

Abstract: An MRI antenna is disclosed comprising a first coaxial cable unit comprising a first inner conductor with first and second ends and a first outer conductor substantially surrounding the inner conductor. The first outer conductor has first and second ends. The first coaxial cable unit has a concave curvature facing a first direction. A second coaxial cable unit is provided comprising an inner conductor with first and second ends and an outer conductor substantially surrounding the inner conductor. The outer conductor has first and second ends and the second coaxial cable unit has a concave curvature facing a second direction opposite the first direction. The concave curvature of the first and second coaxial cable units generally face each other to define a region for receiving a body part. The first end of the first inner conductor is connected to the first end of the second inner conductor through a first capacitor.

Abstract: In magnetic resonance imaging (“MRI”), RF power is applied to a region of interest within the patient by a local antenna disposed adjacent the region of interest. The local antenna is excited by RF signals sent through free space from a principal antenna mounted to the primary field magnet of the MRI system. The principal antenna includes one or more loops mounted so that the plane of the loop is transverse to the pole pieces of the magnet frame and so that the plane of the loop is transverse to adjacent metallic portions of the frame. The loops are aligned with openings in the frame so that a patient is advanced into a frame through the loop. The loops do not substantially obstruct axis to the subject receiving space.

Abstract: An antenna system for a magnetic resonance imaging apparatus has an active coil connected between a transmitter or receiver and ground and also has an isolated loop coil which is not conductively connected to ground. The isolated loop coil preferably overlies the electrically conductive pole surface of the field magnet. The isolated loop coil is inductively coupled to the active coil. The assembly has relatively low parasitic capacitance to ground and hence can be tuned to the resonant frequencies required for high field strength imaging.

Abstract: In magnetic resonance imaging ("MRI"), RF power is applied to a region of interest within the patient by a local antenna disposed adjacent the region of interest. The local antenna is excited by RF signals sent through free space from a principal antenna mounted to the primary field magnet of the MRI system. The principal antenna includes one or more loops mounted so that the plane of the loop is transverse to the pole pieces of the magnet frame and so that the plane of the loop is transverse to adjacent metallic portions of the frame. The loops are aligned with openings in the frame so that a patient is advanced into a frame through the loop. The loops do not substantially obstruct axis to the subject receiving space.

Abstract: An antenna structure for magnetic resonance imaging includes a plurality of spiral wound, generally planar coils spaced axially from one another. The plural coils may be mounted on a rigid frame in the desired relative positions and the subject may be inserted in the space defined by the frame. Alternatively, the individual coils can be separately supported on the subject, as by mounting the coils to the subject. Desirably, a part of the subject's body extends through central apertures in one or more of the coils.