摘要:
A magnetic resonance imaging (MRI) system including a gradient coil system. The gradient coil system comprises an inner coil configuration (1,2,3) and an outer coil configuration (4,5,6) positioned substantially coaxially with said inner coil configuration (1,2,3). Both coil configurations are attached to a tubular body (7) located between said two coil configurations (1,2,3;4,5,6) and extending substantially coaxially with both said coil configurations. The tubular body (7) comprises stainless steel rods (10) positioned substantially in axial direction.
摘要:
The invention relates to an MRI system (1) comprising an examination volume (11), a main magnet system (13) for generating a main magnetic (field (B0) in the examination volume, a gradient magnet system (19) for generating gradients of the main magnetic field, and an anti-vibration system (39) for reducing vibrations of the gradient magnet system. According to the invention the anti-vibration system comprises a gyroscope (41) which is mounted to the gradient magnet system. As a result of the gyroscopic effect of the gyroscope, the vibrations of the gradient magnet system are effectively reduced. In an open type MRI system (1) according to the invention, a separate gyroscope (41, 43) is mounted to each of the two portions (21, 23) of the gradient magnet system (19), and each gyroscope has an axis of rotation (61) parallel to the main direction (Z) of the main magnetic field (B0).
摘要:
The invention relates to a magnetic resonance imaging (MRI) system comprising an examination volume (9), a main magnet system (17) for generating a main magnetic field (Bo) in the examination volume, a gradient magnet system (25) for generating gradients of the main magnetic field, and a control system (37) for compensating disturbances of the magnetic field caused by mechanical vibrations of the MRI system. According to the invention, the control system is a feed-forward control system which determines a necessary compensation for said disturbances in dependence on an electric current in the gradient magnet system according to a predetermined response relation. Since in most MRI systems the mechanical vibrations are predominantly caused by the altering electric currents in the gradient magnet system and by eddy currents induced thereby, the invention provides an accurate and reliable compensation for said disturbances, so that artifacts and other distortions of the reconstructed image caused by said disturbances are considerably reduced.
摘要:
The invention relates to a magnetic resonance imaging (MRI) system (1) comprising an examination volume (11), a main magnet system (17) for generating a magnetic field (B0) in the examination volume, and a gradient magnet system (25) for generating altering gradients of the magnetic field in the examination volume. The gradient magnet system is accommodated in a housing (31) having a main wall (33) facing the examination volume and a substantially conical wall (35) facing away from the examination volume. The main wall and the conical wall enclose a substantially angular tip portion (47) of the housing. In order to limit the level of the acoustic vibrations in and around the MRI system (1) caused by mechanical vibrations of the angular tip portion (47), the MRI system comprises a plurality of acoustic resonators (55) which each comprise an elongate resonance volume (57) with an open end (59) and a closed end (61) and a length (L) between the open end and the closed end. The open ends of the resonators are arranged near the angular tip portion, and the length of the resonators is substantially equal to 0.25 k*(, wherein k=1, 3, 5, 7, . . . , and wherein ( is the wavelength of an acoustic wave caused by mechanical vibrations of the angular tip portion. The resonators have the acoustic property of neutralizing acoustic waves having said wavelength (. Preferably, the length of the resonators is tuned to at least one of the wavelengths corresponding to the mechanical resonance frequencies of the vibrating angular tip portion, as the acoustic waves originating from the vibrations at these resonance frequencies constitute a main portion of the overall acoustic level of the MRI system.
摘要:
The invention relates to a treatment room (7) suitable for recording images of a human or animal body on the basis of a magnetic resonance (MR) imaging technique, the walls (7a), the ceiling (7b) and the floor (7c) of the treatment room forming an electromagnetic shield for a magnetic resonance (MR) imaging system (1) arranged in the treatment room, which MR imaging system comprises at least a target area (5) in which a human or animal body can be placed, a housing (2, 3, 4) comprising at least one main magnetic unit and at least one gradient magnetic unit for generating one or more magnetic fields in the target area (5), and at least one radio-frequency (RF) pulse unit (6) for generating an electromagnetic RF pulse in the target area (5). The invention further relates to a magnetic resonance imaging system comprising a target area in which a human or animal body can be placed, a housing comprising at least one main magnetic unit and at least one gradient magnetic unit for generating one or more magnetic fields in the target area, and at least one radio-frequency (RF) pulse unit for generating an electromagnetic RF pulse in the target area. In accordance with the invention, means (10, 11, 12, 13, 14, 15, 16, 17) are present which, in operation, counteract the electromagnetic effects (8) of the RF pulse in the treatment room (7) outside the target area (5).
摘要:
The present invention relates to a gradient coil system for magnetic resonance imaging (MRI) systems and to a magnetic resonance imaging (MRI) system comprising such a gradient coil system. Magnetic resonance imaging systems comprise at least a main magnet system, a gradient coil system, a RF system and a signal processing system. The gradient coil system according to the present invention comprises at least two X primary coil-like elements (X1pc, X2PC), at least two Y primary coil-like elements (Y1pc, Y2pc) and one Z primary coil-like element (ZPC) providing a modular gradient coil system, wherein the at least two X primary coil-like elements (X1PC, X2PC) have mutually different linearity volumes by themselves or in combination with each other, the at least two Y primary coil-like elements (Y1PC, Y2PC) have mutually different linearity volumes by themselves or in combination with each other, and the one Z primary coil-like element (ZPC) is placed between the X primary coil-like elements (X1PC, X2PC) and the Y primary coil-like elements (Y1PC, Y2PC).
摘要翻译:本发明涉及用于磁共振成像(MRI)系统的梯度线圈系统和包括这种梯度线圈系统的磁共振成像(MRI)系统。 磁共振成像系统至少包括主磁体系统,梯度线圈系统,RF系统和信号处理系统。 根据本发明的梯度线圈系统包括至少两个X初级线圈状元件(X 1 PC 2,X 2 PC),至少两个Y初级线圈状元件, (Y 1 PC 2,Y 2 PC)和一个Z初级线圈状元件(Z PC PC),提供模块化梯度线圈系统 ,其中所述至少两个X初级线圈状元件(X 1 PC 1,X 2 PC PC)本身或彼此组合具有相互不同的线性体积, 至少两个Y初级线圈状元件(Y 1 PC PC 2,Y 2 PC PC)本身或彼此组合具有相互不同的线性体积,并且一个Z 初级线圈状元件(Z PC PC)放置在X初级线圈状元件(X 1 PC 1,X 2 PC PC)和 Y初级线圈状元件(Y 1 PC 1,Y 2 PC PC)。
摘要:
The invention relates to an MRI system (1) for nuclear magnetic resonance imaging which comprises a plurality of transmit coils (11, 12). Each coil receives a coil drive signal (SD1, SD2). The respective coil drive signals have the same shape, but may have a different amplitude and phase, controlled by a controller (103) on the basis of characteristic information in a memory (104) as well as user input information. The controller is designed to set the respective amplitudes and phases in such a way that the resultant overall B1 field is as homogeneous as possible in a volume of interest.