摘要:
The invention relates to a method of MR imaging of at least a portion of a body (110) of a patient placed in an examination volume of a MR device, the method comprising the steps of:—subjecting the portion of the body (110) to an imaging sequence comprising at least one RF pulse, the RF pulse being transmitted toward the portion of the body (110) via a RF coil arrangement (109) to which RF signals are supplied by two or more RF power amplifiers the RF power amplifiers being activated alternately during the imaging sequence in a time-multiplexed fashion, wherein the imaging sequence requires a RF duty cycle and/or a RF pulse duration exceeding the specification of at least one of the RF power amplifiers;—acquiring MR signals from the portion of the body (110); and—reconstructing a MR image from the acquired MR signals. Moreover, the invention relates to a method of MR spectroscopy involving the alternating use of RF power amplifiers in a time-multiplexed fashion.
摘要:
An apparatus comprising—an imaging component for acquiring magnetic resonance images;—a storage component for storing the magnetic resonance images in a stack;—a sorting component for sorting the magnetic resonance images in the stack using machine defined meta information of the images; and—an interface for reading the ordered stack.
摘要:
A magnetic resonance imaging system (10) includes a local coil (40) for receiving a resonance signal induced by a whole body quadrature coil (32). The local coil (40) includes a dielectric former (68) in which a plurality of receive coils (60, 74, 76, 78) and a passive B0 and B1 field shim (62, 82) are mounted. The passive shim includes a plurality of capacitively coupled elements (64) of an electrically conductive diamagnetic, paramagnetic, ferromagnetic material which passively shield and enhance the field in local regions. A surface configuration of the elements is tailored to optimize local B1 homogeneity and a mass of the elements is configured to optimize local B0 field homogeneity.
摘要:
The invention relates to a method of MR imaging of at least a portion of a body (110) of a patient placed in an examination volume of a MR device, the method comprising the steps of:—subjecting the portion of the body (110) to an imaging sequence comprising at least one RF pulse, the RF pulse being transmitted toward the portion of the body (110) via a RF coil arrangement (109) to which RF signals are supplied by two or more RF power amplifiers the RF power amplifiers being activated alternately during the imaging sequence in a time-multiplexed fashion, wherein the imaging sequence requires a RF duty cycle and/or a RF pulse duration exceeding the specification of at least one of the RF power amplifiers;—acquiring MR signals from the portion of the body (110); and—reconstructing a MR image from the acquired MR signals. Moreover, the invention relates to a method of MR spectroscopy involving the alternating use of RF power amplifiers in a time-multiplexed fashion.
摘要:
An magnetic resonance examination system for examination of an object comprises an RF system to generate an RF transmission field and gradient system to generate temporary magnet gradient fields. A control module includes a sequence controller to control the RF system and the gradient system to produce acquisition sequences including RF pulses and magnetic gradient pulses to generate magnetic resonance signals. The sequence controller is configured to produce an detection scan including a steady state gradient echo acquisition sequence to generate steady state gradient echo signals and an RF spoiled echo acquisition sequence to produce RF spoiled echo signals. The control module further including an analysis unit to compare the gradient echo signals to the RF spoiled echo signals and for detection of an instrument in the object from the comparison of the gradient echoes and the RF spoiled echoes.
摘要:
An apparatus comprising—an imaging component for acquiring magnetic resonance images;—a storage component for storing the magnetic resonance images in a stack;—a sorting component for sorting the magnetic resonance images in the stack using machine defined meta information of the images; and—an interface for reading the ordered stack.
摘要:
The invention relates to a nuclear magnetic resonance imaging radio frequency—receiver (112; 216; 308; 404), the receiver (112; 216; 308; 404) being adapted to receive analogue signals from at least one radio frequency receiver coil unit (106; 200; 202; 300; 400; 402), the radio frequency receiver (112; 216; 308; 404) comprising: an analogue-digital converter (118; 226) to convert the analogue pre-amplified magnetic resonance signal into a digital signal, means (120; 230) for digital down converting the digital signal and a first communication interface (130; 252) adapted for transmitting the down converted digital signal via a communication link (e.g. wireless, optical or wire-bound).
摘要:
A magnetic resonance imaging system comprises a receiver system to acquire magnetic resonance signals. A control system controls the receiver system to reform an acquisition sequence to acquire the magnetic resonance signals in several acquisition segments. Respective groups of acquisition segments involve acquisition of magnetic resonance signals in different RF-receiver frequency bands. In the respective groups of acquisition segments, magnetic resonance signals are acquired from different nuclei having different gyromagnetic ratios. According to the invention, reconstruction of different types of information carried by the respective nuclei is made possible. For example, imaging of the anatomy of a patient to be examined is performed on the basis of proton magnetic resonance imaging. Imaging of a targeted contrast agent is achieved on the basis of 19F magnetic resonance imaging. Localisation of a invasive device, such as a catheter, is also performed on the basis of e.g. 19F magnetic resonance imaging.
摘要:
A novel magnetic resonance imaging method is described, for forming an image of an object from a plurality of signals sampled in a restricted homogeneity region of a main magnet field of a magnetic resonance imaging apparatus. A patient disposed on a table is moved continuously through the bore of the main magnet and spins in a predetermined area of the patient are excited by an excitation pulse from a transmitter antenna, such that an image is formed over a region exceeding largely the restricted region. Data is undersampled in the restricted region by means off at least one receiver antenna in a plurality of receive situations being defined as a block of measurements contiguous in time having preserved magnetisation and presaturation conditions within the excited area of the patient. Fold-over artefacts due to said undersampling are unfolded by means of the known sensitivity pattern of the receiver antenna and/or the properties of selected factors determining said receive situations.
摘要:
The present invention relates to a method of perfusion imaging comprising: performing a first magnetic resonance data acquisition (A) at a first sensitivity (b) value, performing a set of at least six second magnetic resonance data acquisitions (B1, B2, . . . B6) with gradiant encodings in different directions at second sensitivity (b) values, determining a perfusion tensor based on the magnetic resonance data acquisitions, performing a perfusion tensor visualitation step.