Title of article :
A New Method for Measurement of Radio Frequency Inhomogeneity in MRI
Author/Authors :
Oghabian, M. A Tehran University of Medical Sciences - Medical Physics department, Tehran , Riahi Alam, N Tehran University of Medical Sciences - Medical Physics department, Tehran , Mehdipour, S Imam Hospital, Tehran
Abstract :
Weintroducea newmethodofmeasuringtransmitandreceiveRFinhomogeneity
indifferentRFcoils ofMRIsystems. In thismethoda single sliceofa uniformphantom is
imagedfromdifferentflipangles,usinga standardspinechoprotocol.Thesignalintensityin
these images is then fitted to a mathematicalmodelwhich describes the relationshipbetween
thesignalintensityandflipangleofthespinechoimages.Theresultsofthiscurve
fittingprocess aretwoparameters,T(r)and R(r),whosevariationwith thespatialposition
showsRFtransmit,andreceivenon-uniformity,respectively.
Inthisapproacha linearprofileofB1fielddistributionandreceivesensitivityofRFcoilsare
achievedwhichisalsoapplicableinvivo. Themethodcanbeusedtoassessanycommercial
MR scannerand is highly recommended for thequality control (QC) of thoseMRscanners
whicharedevoidofcomplicatedprotocolssuchasSE(-2).Suchsystemsarestillrunning
indifferentclinicsespeciallyinthedevelopingcountrieswherethelatesthighperformance
MRscannersarenotavailableandmanyscannerslackstandardmaintenanceservices.
Keywords :
Magnetic Resonance Imaging , RF inhomogeneity , Image nonuniformity , spin echo
Journal title :
Astroparticle Physics
