Toshiba America Mri, Inc.

Sunyu Su

Leon Kaufman

Mitsuaki A Arakawa

Joseph W Carlson

An inherently de-coupled sandwiched solenoidal array coil (SSAC) is disclosed for use in receiving nuclear magnetic resonance (NMR) radio frequency (RF) signals in both horizontal and vertical-field magnetic resonance imaging (MRI) systems. In its most basic configuration, the SSAC comprises two coaxial RF receive coils. The first coil of the array has two solenoidal (or loop) sections that are separated from one another along a common axis. The two sections are electrically connected in series but the conductors in each section are wound in opposite directions so that a current through the coil sets up a magnetic field of opposite polarity in each section. The second coil of the SSAC is disposed (&ldquo;sandwiched&rdquo;) between the two separated solenoidal sections of the first coil in a region where the combined opposing magnetic fields cancel to become a null. Due to the winding arrangement and geometrical symmetry, the receive coils of the array become electromagnetically &ldquo;de-coupled&rdquo; from one another while still maintaining their sensitivity toward receiving NMR signals. The multiple coil array arrangement also allows for selecting between a larger or smaller field-of-view (FOV) to avoid image fold-over problems without time penalty in image data acquisition. Alternative embodiments are disclosed which include unequal constituent coil diameters, unequal constituent coil windings, non-coaxial coil configurations, a three-coil quadrature detection (QD) SSAC arrangement, multiple SSAC arrangements, and optimized SSAC configurations for breast imaging in both horizontal and vertical-field MRI systems.

Inherently de-coupled sandwiched solenoidal array coil

Flexible, region-selectable inherently de-coupled sandwiched solenoidal array coil

An RF quadrature detection coil for interventional MRI comprises two nested orthogonal coils having generally rectangular shape in profile, each coil providing one &ldquo;channel&rdquo; of signal for quadrature detection. Each rectangular coil has two conductor windings and a common side in which the two conductors along that side are displaced apart in a common plane orthogonal to the plane of the coil to form a circular opening. The two individual coils are configured such that their rectangular conductor winding portions lie in planes perpendicular to each other but their arcuate conductor winding portions coincide in the same plane. Four paralleled conductors are arranged around the shared circular opening while two paralleled conductors form the three sides of the rectangular portion of each individual coil. With this arrangement, the circular opening allows for entry of a body part for MR imaging while the spaces between the orthogonal rectangular sides of the two coils provide large open access areas for one or more instruments during interventional procedures.

Quadrature detection coil for interventional MRI

A pair of RF quadrature detection coils are fitted in an open support structure that allows easy diagnostic access to all tissue areas of the human female breast when performing interventional MRI. The open structure dual coil arrangement comprises a flat base and a slightly 'V'-shaped bi-planar upper section supported above the lower base section by eight narrow vertical legs. The upper bi-planar section includes two circular openings for accepting the breasts. Four of the support legs are equally spaced at 900 intervals around each breast opening and provide large side-open access areas to the breast tissues via the sides of the support structure. The 'V'-shape of the upper portion of the coil support structure increases the gap clearance at both left and right sides of the support structure to further enhance access to the breasts. In a preferred embodiment, two complete MRI quadrature detection coils are supported by the structure and each of the vertical support legs house a pair of conductors forming part of a quadrature detection coil winding. The use of quadrature detection coils increases MRI signal detection efficiency and the open structural support arrangement allows increased accessibility to the breast tissues for efficient interventional MR imaging and easy cleaning after use.

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South San Francisco, CA, United States of America

Sunyu Su