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.