Siemens Aktiengesellschaft

Peter Heubes

Thorsten Feiweier

Stephan Biber

Wilfried Schnell

Berthold Kiefer

Thorsten Speckner

Stephan Kannengiesser

Swen Campagna

Ludwig Eberler

Martin Harder

Qiang He

Cecile Mohr

Michael Moritz

Katrin Wohlfarth

Volker Weissenberger

Bernd Stoeckel

Rainer Kaim

A local coil arrangement for magnetic resonance applications has a base body in which at least one local coil is arranged. An excitation signal to excite an examination subject to emit a magnetic resonance signal can be emitted by the local coil and/or a magnetic resonance signal emitted by the examination subject can be received by means of said local coil. At least one volume region is present in the base body, in which an amount of a substance is located that can be excited by means of the coil or another coil so as to emit a magnetic resonance signal. A shielding is arranged in the base body. The shielding can be controlled so as to either shield or not shield the volume region depending on the control state, so that the volume region is occluded or visible with regard to magnetic resonance applications.

Local coil arrangement for magnetic resonance applications with activatable marker

A magnetic resonance tomography device has a magnet system that generates a gradient field; with a local coil that receives a magnetic resonance signal; and with a localization system that is fashioned to locate the local coil. The localization system has a number of magnetic field sensors that are integrated with the local coil and fashioned to detect the gradient field. Such a device is used in a corresponding method for localization of a local coil in a magnetic resonance tomography device, and a local coil is fashioned so as to be suitable for this purpose.

Magnetic resonance tomography device with localization system and method to localize a local coil

In a method for adjustment of the field strength of radio-frequency pulses as well as a magnetic resonance measurement system, radio-frequency pulses are emitted by a radio-frequency antenna of a magnetic resonance measurement system in a magnetic resonance measurement. A test volume slice is initially excited by emission of radio-frequency pulses with a defined pulse amplitude by the appertaining radio-frequency antenna and one-dimensional, spatially-resolved characteristic values are determined along an extent direction of the test volume slice. The one-dimensional, spatially-resolved characteristic values respectively represent a local field strength of the Bfield in strips of the test volume slice running perpendicular to the extent direction. An average value of the determined characteristic values is then formed over at least over one determined segment along the extent direction of the test volume slice. A pulse amplitude of the radio-frequency pulses that is to be set for the magnetic resonance measurement to be implemented is determined on the basis of the average value.

Method and magnetic resonance system for adjustment of the field strength of RF pulses

In an apparatus for processing and presenting a magnetic resonance tomography measured image wherein following simultaneous calculation of the contrast images of various spin ensembles or various MR images of a spin ensemble (anatomical, angiographic, functional), a step-free fade of the contrast images can be undertaken with an input device. A multi-colored presentation can be used in addition to the gray scale presentation dependent on the spin ensemble.

Magnetic resonance tomography apparatus with step-free fade between displayed different spin ensembles

The present invention concerns a method and an apparatus for phase-calibrating an MRI pulse sequence which is used to calculate a linear phase and a constant phase to perform phase calibration on the scanned data, wherein a corresponding pre-scan without a phase encoding gradient is performed before a diagnostic scan. A reference echo is selected from the echoes obtained in the pre-scan. On the basis of the reference echo the constant phase is calculated to be used in performing the phase calibration in the scan. The constant phase that is obtained is correct and not affected by phase jumping. A further image reconstruction performed on the phase-calibrated data produces clear and artifact-free images.

Method and apparatus for phase calibration of an MRI pulse

In a method for implementation of a magnetic resonance examination of a patient with an imaging medical magnetic resonance apparatus with a movable patient bed, for of an examination volume of the patient that is larger than an acquisition volume of the magnetic resonance apparatus, anatomical patient information and second technical information for setting the magnetic resonance apparatus are acquired dependent on the position of the patient bed from magnetic resonance signals acquired in a low-resolution calibration measurement (scan). A first group of measurement protocol parameters is generated from the patient information and a second group of measurement protocol parameters is generated from the technical information, to generate a measurement protocol for a subsequent high-resolution magnetic resonance examination.

Method for implementation of a magnetic resonance examination of a patient

In a magnetic resonance tomography method and apparatus for avoiding peripheral interference signals in magnetic resonance tomography when using spin-echo sequences, the average frequency and the bandwidth of the radio-frequency excitation pulse differ from the average frequency and the bandwidth of the radio-frequency refocusing pulse(s), and the amplitude of the slice selection gradients activated during the radio-frequency excitation pulse differing from the amplitude of the slice selection gradient(s) activated during the radio-frequency refocusing pulse, such that the excitation slice of the RF excitation pulse and the refocusing slice of the RF refocusing pulse(s) in the homogeneous volume (FOV) of the basic magnetic field are superimposed, while the excitation slice of the RF refocusing pulse(s) in the non-homogeneous volume of the basic magnetic field are separated locally, and an echo signal is thereby prevented in the non-homogeneous volume.

Magnetic resonance tomography method and apparatus with suppression of ambiguity artifacts in spin echo images

In a method and magnetic resonance tomography apparatus for spatially resolved measurement of the magnetic high frequency field distribution in the apparatus, a double echo high frequency pulse sequence with a first excitation pulse following by at least two refocusing pulses are emitted for generation of a first echo and a following second echo. At least the excitation pulse is slice selective. In an excitation layer defined by the slice selective excitation pulse a first echo image and second echo image are spatially resolved by using suitable gradient pulses for phase or frequency encoding Using the relationships of the amplitudes of the first and second echo image in the various locations the flip angles representing the field strength at the relevant locations in the relevant slice are determined.

[object Object]

In a multi-echo magnetic resonance imaging method a number of high-frequency pulses are generated involving a high-frequency excitation pulse and a number of following high-frequency refocusing pulses, at least two phase encoding gradient pulses are respectively generated between the high-frequency refocusing pulses, and at least two compensation phase encoding gradient pulses are generated between the high-frequency excitation pulse and the first high-frequency refocusing pulse.

Multi-echo magnetic resonance imaging method with reduction of artifacts caused by remanence magnetization

An antenna for a magnetic resonance device comprises an antenna conductor structure and capacitors connected thereto. The antenna conductor structure and/or the capacitors are connected to a water cooling system.

Antenna for a magnetic resonance device

In a method for avoiding image occlusions in nuclear magnetic resonance tomography apparatus that are operated with multi-echo sequences, at a time t.sub.0, a cross-magnetization in spins is generated in an examination subject with an excitation radio-frequency pulse. At times t.sub.1, t.sub.3, t.sub.5 . . . , at least two refocusing radio-frequency pulses that re-phase the cross-magnetization follow and read-out intervals follow at times t.sub.2, t.sub.4, t.sub.6 . . . The following condition is satisfied in at least one direction for the gradients G activated during the pulse sequence: ##EQU1## Even given quadratic gradient terms, thus, no phase difference occurs between a primary and a stimulated echo path. The presence of such a phase difference causes an image occlusion, and thus such occlusions are avoided by eliminating such a phase difference.

Method for avoiding image occlusions in nuclear magnetic resonance

A pulse sequence is disclosed for a nuclear magnetic resonance tomography apparatus wherein the scans are executed with a non-constant repetition time, such as due to ECG triggering. Normally, the non-constancy of the repetition time in a nuclear magnetic resonance tomography apparatus results in a deterioration of the quality of the images, due to eddy currents. In the pulse sequence disclosed herein, gradient pulses having a chronological mean value are inserted in the pause between two successive scans, this chronological mean value being equal to the chronological mean value of the corresponding gradients during the scans. The disturbing influence of variable repetition times on the image quality is thus eliminated.

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Poxdorf, Germany

Peter Heubes