U.S. Philips Corporation

Eddy B Boskamp

Rudolf Kemner

For measurements with increased accuracy in a nuclear magnetic resonance apparatus, the detection device is equipped with one or more surface coils which act as measuring coils. To avoid mutual interference between a radio-frequency transmitting coil and the measuring coil, the measuring coil is provided with a decoupling circuit. The surface coil and the decoupling circuit form a part of a tuned circuit which is tuned to a significantly higher natural frequency during activation of the transmitting coil. On the other hand, the transmitting coil is shorted during detection with the surface coil by a low resistance shorting circuit, thereby avoiding interference with the radio-frequency transmission signals.

Nuclear magnetic resonance apparatus with surface coil detection

A magnetic resonance imaging apparatus includes a cascade of surface coils for detection so that larger objects can be measured while the attractive signal-to-noise ratio of surface coils is retained without mutual re-orientation of coils with respect to the object being required. By introducing a partial overlap between successive coils, suitable homogeneity can be achieved for the detection.

Magnetic resonance imaging apparatus comprising a stacked surface coil

A surface coil used as a measuring coil in a magnetic resonance apparatus is divided into at least two coil portions having opposite directions of winding and enclosing two identical surface areas. An induction current generated in a coil portion by a transmission field is then always compensated for by a current generated in the other coil portion. When one or more of such butterfly coils are used no circuits to block interfering signals need be built into the electronic measuring circuit and the transmission field is not disturbed by the measuring coil.

Magnetic resonance apparatus with a decoupling detection surface coil

The detection coil of a magnetic resonance imaging apparatus comprises a stack of two coils with locally mutually perpendicularly directed B Fields. The first coil is formed as a butterfly coil having a B field extending parallel to the plane of the coil, the second coil being formed by a single flat coil having a B field extending transversely of the plane of the coil. The coils are arranged in a fixed mutual orientation so that for each of the coils reciprocally applied fluxes are always compensated for.

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Eindhoven, Netherlands

Eddy B Boskamp