摘要
Objective:To establisha curveof dosagegradient-liversignalintensityof super-paramagneticironoxide(SPIO)in normalratsand to findan appropriateenhancementdosage.Methods:Seventy-twoSD ratswere randomizedinto18groups(n=4),receivedMRenhancementof0,2,5,8,10,12,15,20,30,40,50,60,70,80,100,140,210,280μmol/kgSPIOafterplaneexamination.Thesignal-to-noiseratioof liverwas measuredto makea curveof dosagegradient-liversignalintensity.Results:(1)Thesignalintensityof bothT 1 andT 2 weightedimagesof liverdeclinedwiththeincreaseof SPIO.(2)T 2 weightedimagesweremoresensitivethanT 1 weightedimagesin smalldosage,theED50of T 1 andT 2 weightedwere8μmol/kgand5μmol/kgrespectively.(3)Whenthedosewas greaterthan15μmol/kg,thesignalintensityof T 1 weightedimagesdeclinedmorerapidlythanthatof T 2 weighted,theeffectof enhancedT 1 weightedimageswassimilarto T 2 weightedones,anditsimageswerewithnicerresolution.(4)Atthedoseof40μmol/kg,thesignalintensityof T 1 weightedimagesapproachedto thebackgroundnoise;at the doseof15μmol/kg,thesignalintensityof T 2 weightedimagesapproachedto thebackgroundnoise.Conclusion:Goodeffectof T 1 andT 2 enhancedMR imagingcanbe acquiredat thedoseof20to10μmol/kgSPIOrespectively,thebestcontrast-to-noiseratioisfoundon T 2 -weightedenhancedMRimage.
Objective:To establisha curveof dosagegradient-liversignalintensityof super-paramagneticironoxide(SPIO)in normalratsand to findan appropriateenhancementdosage.Methods:Seventy-twoSD ratswere randomizedinto18groups(n=4),receivedMRenhancementof0,2,5,8,10,12,15,20,30,40,50,60,70,80,100,140,210,280μmol/kgSPIOafterplaneexamination.Thesignal-to-noiseratioof liverwas measuredto makea curveof dosagegradient-liversignalintensity.Results:(1)Thesignalintensityof bothT 1 andT 2 weightedimagesof liverdeclinedwiththeincreaseof SPIO.(2)T 2 weightedimagesweremoresensitivethanT 1 weightedimagesin smalldosage,theED50of T 1 andT 2 weightedwere8μmol/kgand5μmol/kgrespectively.(3)Whenthedosewas greaterthan15μmol/kg,thesignalintensityof T 1 weightedimagesdeclinedmorerapidlythanthatof T 2 weighted,theeffectof enhancedT 1 weightedimageswassimilarto T 2 weightedones,anditsimageswerewithnicerresolution.(4)Atthedoseof40μmol/kg,thesignalintensityof T 1 weightedimagesapproachedto thebackgroundnoise;at the doseof15μmol/kg,thesignalintensityof T 2 weightedimagesapproachedto thebackgroundnoise.Conclusion:Goodeffectof T 1 andT 2 enhancedMR imagingcanbe acquiredat thedoseof20to10μmol/kgSPIOrespectively,thebestcontrast-to-noiseratioisfoundon T 2 -weightedenhancedMRimage.
