Albert-ludwigs-universitat Freiburg

Albert-ludwigs-universitaet Freiburg

Feng Jia

Maxim Zaitsev

Jan Korvink

Sebastian Littin

Zhenyu Liu

Jan Gerrit Korvink

Philipp Amrein

A carrier structure () of an arrangement () for modifying a main magnetic field generated in a magnetic resonance tomograph from multiple carrier elements (). A conductor arrangement () is respectively arranged on each carrier element (). The conductor arrangements () respectively include a primary conductor arrangement () for generating a primary magnetic field that modifies the main magnetic field and a secondary conductor arrangement () for shielding the primary magnetic field. A method for producing a modularly constructible arrangement () is provided, which can be used for example for spatial encoding.

Arrangement for modifying a main magnetic field and method for producing such an arrangement

A method for designing an electromagnetic gradient coil for magnetic resonance imaging systems. The method includes the steps of: choosing a set of objectives L, whereby the objectives Lare combined to one weighted-sum objective function; choosing a design variable &#x3c8; for modifying the value of the objectives L; making an initial guess of the value of the design variable &#x3c8;; simulating the magnetic field in a computational domain with respect to the distribution of the surface current density; carrying out a sensitivity analysis by calculating a sensitivity vector G=&#x2202;L/&#x2202;&#x3c8;; updating the design variable &#x3c8;, whereby the value of the design variable &#x3c8; is changed in order to decrease the value of the objective L; determining whether convergency is achieved by either determining whether the value of the objective function does not decrease or the whether the Euclidian norm of the sensitivity vector G approximate to zero; and reconstruction of a discretized coil. The simulation of the magnetic field in a computational domain is effected using a least square finite element analysis. The steps are repeated prior to reconstruction of a discretized coil until convergency is achieved. An effective and improved design for irregular surfaces is thereby created.

MRI gradient coil

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Freiburg, Germany

Feng Jia