GE磁共振簡(jiǎn)稱(chēng)綜合材料

1、glossaryacgdadvanced concept gradient driveragpapplications gateway processor boardaparray processor boardapmanalog power monitor boardapsauto prescan: auto-adjustment of data acquisition (scan) parametersapsacquisition processing system boardavsauto voxel shimawsautomatic water suppressionbrmbody r

2、esonance modulebrmbody resonance modulecancontrol area network boardccccan core communication boardcrmcardiac resonance modulecrtcathode ray tubecryogena substance for producing low temperatures. liquid helium is the cryogen used to cool the magnet to approximately 4 kelvin (269 c or 452 f).cryostat

3、an apparatus maintaining a very low constant temperature. the cryostat consists of one concentric, cylindrical container housed in an outer vacuum tight vessel. the magnet and shim coils are mounted in the inner container. the container is filled with liquid helium. the shields surrounding the inner

4、 container are kept cold by a refrigeration device.cvcontrol variabledcbdriver control boarddewara container with an evacuated space between two highly reflective walls used to keep low temperature substances at nearconstant temperatures. liquid helium is usually stored and shipped in dewarsdmdriver

5、 moduledrf1digital receive filter 1 boarddspdigital signal processingexclusion zonearea where the magnetic flux density is greater than five gauss. personnel with cardiac pacemakers, neurostimulators and other biostimulation devices must not enter this zone. signs are posted outside the five gauss l

6、ine alerting personnel of this requirement. since the magnetic field is threedimensional, signs are also posted on floors above and below the magnet room in which the five gauss line exists.ferrous materialany substance containing iron which is strongly attracted by a magnetic field.fofiber opticfov

7、field of viewfpiofront panel input/output boardfwhmfull width half maxgauss (g)a unit of magnetic flux density. the earths magnetic field strength is approximately one half gauss to one gauss depending on location. the internationally accepted unit is the tesla (1 tesla = 10,000g and 1 milli tesla =

8、10g).gpgradient processor boardgradientthe amount and direction of the rate of change in space of the magnetic field strength. in the magnetic resonance system, gradient amplifiers and coils are used to vary the magnetic field strength in the x, y, and z planes.grxgraphic prescriptionhfa high f

9、idelity gradient amplifierhfdhigh fidelity gradient driverhomogeneityuniformity. the homogeneity of the static magnetic field is an important quality of the magnet.icnimage compute node.  a component with an internal operating system (similar to a pc) used for image reconstruction in the vre.&#

10、160; contains hard drives and an operating systemicwinstallation calibration wizard.  this wizard is available in two different modes: install and upgrades.  it can be found in the proprietary common service desktop under the "calibration" tab.  maintenance mode is available

11、 after all calibrations and tasks in the install mode are complete.ifccimage file create and cleanupinfinibandhigh-speed communication, analogous to ethernet but much higher speed and capacity.  used for transporting large amounts of data for within the volume reconstruction subsystemirfinterfa

12、ce and remote functions boardirf i/ointerface and remote functions input/output boardisocentercenter of the imaging volume ideally located at the magnet center.isogauss linean imaginary line or a line on a field plot connecting identical magnetic field strength points.it hostimage transfer host boar

13、dit-mgdimage transfer-mgd boardlcdliquid crystal displayledlight emitting diodelolocal oscillatorlpcalow profile carriage assemblymagnetic field (h)the space around a magnet (or current carrying conductor) which can produce a magnetizing force on a body within itmagnetic resonance (mr)the absorption

14、 or emission of electromagnetic energy by nuclei in a static magnetic field, after excitation by a suitable radio frequency field.magnetic shieldingusing material (e.g. steel) to redistribute a magnetic field , usually to reduce fringe fields.mcmulticoilmcdmulticoil driver boardmcqamulti coil qualit

15、y assurance.  this is a tool that will check the coil snr and be able to trend it for each coil over time.mgdmulti-generational data acquisition chassismpsmanual prescan: manual adjustment of data acquisition (scan) parametersmrsmagnetic resonance spectroscopymuxmultiplexor boardnexnumber of ex

16、citationsomoxygen monitorowoperator workspacepacphysiological acquisition controllerpciperipheral component interconnectpdupower distribution unitpmcpci mezzanine connecterpppenetration panelpresspoint-resolved spectroscopy, basis for probe-p psdprobe/qautomated analysis and display of probe/sv data

17、probe/svproton brain exam single voxel spectroscopy using automated steam or press pulse sequencepspower supplypsdpulse sequence data baseptpatient transport or patient tablequenchcondition when a superconducting magnet becomes resistive thus rapidly boiling off liquid helium. the magnetic field red

18、uces rapidly after a quench.radio frequency (rf)frequency intermediate between audio frequency and infrared frequencies. used in magnetic resonance systems to excite nuclei to resonance. typical frequency range for magnetic resonance systems is 580 mhz.radio frequency shieldingusing material (e.g. c

19、opper, aluminium, or steel) to reduce interference from external radio frequencies. a radio frequency shielded room usually encloses the entire magnet room.reconprocess that creates an image or spectrum from data acquired with a signa mri scanner.resonancea large amplitude vibration caused by a rela

20、tive small periodic stimulus of the same or nearly the same period as the natural vibration period of the system. in magnetic resonance imaging, the radio frequency pulses are the periodic stimuli which are at the same vibration period as the hydrogen nuclei being imaged.rfradio frequencyrf-difrf-di

21、gital interface boardrfirf interface moduleroiregion of interestrpcremote control panel (twinspeed only)rrfremote rf chassisrspreal-time sequence control parameterss/csuper conductingsatsaturation, a signal suppression techniquescpscan control processor boardscsismall computer system interfacesgaswi

22、tchable gradient amplifier moduleshield cooler cold headan external refrigeration device which maintains the shields inside the cryostat at a constant temperature.shim coilsshim coils are used to provide auxiliary magnetic fields in order to compensate for inhomogeneities in the main magnetic field

23、due to imperfections in the manufacturing of the magnet or affects of steel in the surrounding environment.shimmingcorrection of inhomogeneity of the main magnetic field due to imperfections in the magnet or to the presence of external ferromagnetic objects.smcsystem monitor and controlspusignal pro

24、cessing unitsrfscalable rf cabinet (this is same as srfd)srf/trfsequencer related function / trigger and rotation function boardsrfdscalable rf driver cabinetsrfd2scalable rf driver 2 cabinetsriscan room interface modulessmsystem support modulesteamstimulated echo acquisition mode, basis for probe-s

25、 psdstifsrf/trf interface boardsuper conducting magneta magnet whose magnetic field originates from current flowing through a superconductor. such a magnet is enclosed in a cryostat.superconductora substance whose electrical resistance essentially disappears at temperatures near zero kelvin. a commo

26、nly used superconductor in magnetic resonance imaging system magnets is niobiumtitanium embedded in a copper matrixt1the characteristic time constant for the magnetizations return to the longitudinal axis after being excited by an rf pulse. also called spin lattice or longitudinal relaxation time.t1

27、-weightedscan protocols that allow the t1 effects to predominate over the other relaxation effects.t2*the characteristic time constant for loss of transverse magnetization and mr signal due to t2 and local field inhomogeneties. since such inhomogeneities are not compensated for by gradient reversal,

28、 contrast in gradient-echo images depends on t2*.t2*-weightedscan protocols that allow the t2* effects to predominate over the other contrast effects. there are three primary gradient echo pulse sequences that can be used to produce varying t2*-weighted images: gradient echo, spgr, and ssfp. &#

29、160;t2the characteristic time constant for loss of phase coherence among spins, caused by their interaction, and the resulting loss in the transverse-magnetization mr signal. also referred to as spin-spin or transverse relaxation time.   t2-weighted scan protocols that allow the

30、t2 effects to predominate over the other contrast effects.   te min the shortest possible te time for a given prescription, used to minimize flow dephasing and t2 effects. tesee time to echo. te1the time from the middle of the first excitation pulse to the middle of the

31、 first readout in an asysmmetrical spin echo pulse sequence.   tactwin accessory cabinet (twinspeed only) teecho time te2 the time between the middle of the first excitation pulse and the middle of the second readout in an asysmmetrical spin echo pulse sequence. tesla (t)the internationally accepted unit of magnetic flux density. one tesla is equal to 10,000 gauss. one milli tesla is equal to 10 gauss. tgwctwinspeed gradient water cooler time to echo (te)the time between the center of the excitation