U.S. Philips Corporation

Hewlett-packard Corporation

U.S. Phillips Corporation

Lennart Hofland

Johannes J Van Vaals

Bernard Joseph Savord

Marc Kouwenhoven

Steven A Scampini

Rudolf W De Boer

A method of heating a target region by ultrasound radiation includes determination of a position of the target region by a magnetic resonance method. The device for carrying out this method includes an ultrasound device and an MR device. By determining movement of the target region utilizing the MR device (100) and an appropriate magnetic resonance method, and by coupling the movement information to the ultrasound device (118) by an electric signal (122, 124), it is achieved that the ultrasound device can be controlled by the movement information. Various possibilities exist for controlling the ultrasound device. According to a first possibility, the focal region is adjusted to be situated within the target region in order to generate ultrasound. Another possibility is to determine from the movement information the instant at which the target region is situated within the focal region of the ultrasound and to generate ultrasound exclusively for a brief subsequent period during which the focal region is still within the target region. Another possibility is to refrain from generating ultrasound when the movement speed is too high. Finally, the movement information can also be used for making the focal region follow the target region during the generation of ultrasound.

Method and device for heating by means of ultrasound

In a magnetic resonance method for imaging of a moving part of a body (106) temporary magnetic gradient fields (230) are applied and a echo signal (641, 642) is obtained after an excitation pulse (201). An image of the moving part is reconstructed from the received echo signals (240). The moving part introduces artefacts in the reconstructed image. These artefacts could be reduced when the instantaneous position of the moving part is known and the region of the moving part to be excited is adjusted according to this instantaneous position. This instantaneous position is derived from navigator signals (640). These navigator signals (640) could be generated independently from the other echo signals (641, 642) in the moving part of the body. A further reduction of artefacts in the image could be obtained by deriving a phase correction and a frequency correction from the navigator signals (640) and to apply the derived corrections to the received echo signals (641, 642). Also this method could be combined with ECG-triggering and respiratory gating.

Method of and device for magnetic resonance imaging

An off-resonance magnetization transfer contrast (MTC) RF-pulse (54, 64) is used in magnetic resonance angiography (MRA) to suppress the signal of various stationary tissues, such as brain tissue while avoiding significant suppression of signal from blood flowing in a general direction of blood flow into a slice being imaged. Application of a magnetic gradient (55, 65, 85) during the MTC RF-pulse (54, 64) directed in the general direction of blood flow increases the magnetization frequency offset (86) relative to the center frequency of the MTC RF-pulse for points within and feeding blood to the slice. The MTC RF-pulse thus causes only a small signal reduction of the blood flowing into the slice in the general direction of blood flow while producing a saturation of any blood flowing into the slice in the opposite direction. Consequently, both time and RF-power needed for a separate presaturation pulse can now be used for the MTC RF-pulse.

Device and method for magnetic resonance imaging

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Eindhoven, Netherlands

Lennart Hofland