Unversität Zürich

Eidgenossische Technische Hochschule (eth)

Eidgenossische Technische Hochschule (eth) Eth Zentrum

Klaas Prussmann

Christoph Barmet

David Brunner

Bertram Wilm

Benjamin Dietrich

Maximilian Häberlin

A magnetic resonance (MR) system comprises a main magnetic field and an RF power amplifier for generating an RF field in a first RF band, the arrangement further comprising at least one magnetic field probe (), said magnetic field probe comprising a MR active probe substance, means for pulsed MR excitation of said probe substance () in a second RF band and means for receiving a probe MR signal in the second RF band generated by said probe substance. In order to improve performance of the system, the latter comprises means for recording the output signal of the RF power amplifier in said second RF band, and means for subtracting from said probe MR signal an interfering signal contribution contained in said recorded RF amplifier output signal.

Active noise suppression for magnetic resonance based magnetic field probes

A method of determining an actual gradient impulse response function during execution of a magnetic resonance (MR) imaging or spectroscopy sequence, wherein a main magnetic field is generated in a sample region of an MR apparatus by means of a main magnet and wherein superimposed time dependent gradient fields and radiofrequency fields in a first RF band are generated in the sample region according to a first MR sequence for forming images or spectra, the gradient fields being generated by gradient forming means of the MR apparatus operated according to a gradient forming sequence part of said first MR sequence, the MR apparatus further comprising at least one magnetic field probe. The method comprises the steps of: &#x2014;operating said at least one magnetic field probe according to a second sequence, whereby a time dependent probe signal is repeatedly acquired from each magnetic field probe during a probe acquisition time window, thus providing at least one time dependent probe signal; &#x2014;obtaining said actual gradient impulse response function by calculating an impulse response function from said at least one time dependent probe signal and from said gradient forming sequence part.

Method of determining a gradient impulse response function during execution of a magnetic resonance imaging or spectroscopy sequence

A method of determining the position of at least one magnetic field probe located within a pre-defined volume of interest within a magnetic resonance (MR) imaging or spectroscopy arrangement comprises applying a spatially and temporally variable magnetic reference field having a unique time-course at every point in said volume of interest during a preselected time window. An MR signal is ac-quired from said magnetic field probe during said time window, and the position of the probe is determined from the probe MR signal.

Determining positions of a magnetic field probe in a magnetic resonance measurement

A dynamic field camera arrangement for monitoring electromagnetic field behavior in a spatial region comprises a main magnetic field and a radiofrequency (RF) field limited to a first RF band, particularly in an MRI or NMR apparatus. The arrangement comprises a magnetic field detector set comprising a plurality of low-frequency magnetic field detectors, each one of said magnetic field detectors comprising a magnetic resonance (MR) active substance, means for pulsed MR excitation of said substance and means for receiving an MR signal generated by said substance, wherein said pulsed excitation and said MR detector signal is in a second RF band that does not overlap said first RF band. The MR signal receiving means comprise a first RF filter which suppresses RF signal from said first RF band and transmits RF signal from said second RF band.

Dynamic field camera arrangement for magnetic resonance applications and methods for operating the same

A method of observing axial magnetization (Mz) in an object (O) located in a main magnetic field (B) comprises the step of determining magnetic field intensity (B) in at least one magnetic field probe (P) arranged in the neighborhood of the object. The magnetic field probe comprises a magnetic resonance (MR) active substance, means for pulsed MR excitation of the substance and means for receiving an MR signal generated by said substance.

Growing community of inventors

Zurich, Switzerland

Klaas Prussmann