ApplicativestudyofquantitativeparametersofDCEGMRIand3DGASLinpreoperativegliomagrading / 实用放射学杂志

Objective TostudythevalueofquantitativeparametersofDCE-MRIandthreedimensionalarterialspinlabeling(3D-ASL) inpreoperativegliomagrading.Methods 70patientsdiagnosedpathologicallywithinitialgliomawereassessedretrospectively,including 32caseswithlow-gradeglioma(LGG)and38caseswithhigh-gradeglioma(HGG).Allpatientsunderwentconventional,enhanced, DCEand3D-ASL MRIat3.0Tbeforesurgery.TheparametricvaluesofDCEsuchasvolumetransferconstant(Ktrans),extravascular extracellularspacevolumefraction(Ve),therateconstant(Kep),fractionalplasmavolume(Vp),cerebralbloodflow (CBF)andcerebral bloodvolume(CBV)wereobtainedbycorrespondingpost-processingsoftware.ThecerebralbloodflowofASL (ASL-CBF)wasalso obtained.Ttestoftwoindependentsampleswasusedtoanalyzewhetherthemaximumandaveragevaluesofeachparameterwere statisticallydifferentbetweenLGGand HGG.Thediagnosticaccuracyofdifferenttechniqueforgliomagradingwasdeterminedby ROCcurveanalysis.Results ThemaximumvaluesofDCE-Ktrans,Ve,rCBVandmaximumvalueofASL-rCBFwerestatisticallydifferent betweentheHGGandLGG (P＜0.05).AlltheparametricaveragevalueswerestatisticallydifferentbetweentheHGGandLGG (P＜0.05).ThemaximumandaveragevaluesofKtranshadarelativelyhighestdiagnosticefficiencyinallparameters,withtheAUCwere0.986 and0.971,theoptimumthresholdwere0.264and0.068,thesensitivitywere93.3%and94.1%,andthespecificitywere100%and 100%,respectively.ThemaximumvaluesofVe,rCBV,ASL-rCBFandtheaveragevaluesofallparametershadarelativelyhigher diagnosticefficiency.Conclusion ThemaximumvaluesofKtrans,VeandrCBFofDCE,themaximumvalueofASL-rCBFandtheaverage valueofeachparameterwereusefultodistinguishbetweenLGGand HGG.ThemaximumandaveragevaluesofKtransarethebest parametersforidentifyingHGGandLGG.

The MRI findings of mitochondrial encephalomyopathy,lactic acidosis and stroke-like episodes / 实用放射学杂志

Objective To analyze retrospectively the MR features of MELAS patients,in order to improve the early diagnosis of MELAS.Methods MR data of 1 6 MELAS patients confirmed by clinical diagnose and muscle biopsy were retrospectively analyzed. MR features of plain scan(n=1 6),ASL(n=3),MRA(n=1 5),DWI(n=14)and MRS(n=3)were analyzed.Results MRI data demonstrated brain lesions mainly distributed in posterior cerebral hemisphere extending to subcortical area,which was not consistent with the vascular supply territories.The lesions were observed as low signal on Spin-echo sequence of T1 WI,while high signal on T2 WI, FLAIR and DWI.The focal lesions showed increasing Lac peak on MRS.Fifteen of 16 patients underwent MRA and one showed increased arterial branches in lesion zones.Three patients had ASL scanning demonstrating high irrigation in lesion zones which would wander once relapsed.Meanwhile,old lesions showed encephalatrophy and cerebromalacia.All patients’muscle biopsy pathology showed ragged red muscle fibers.Under electron-microscopic,bioblasts were bigger and more than average level and muscle fibers atrophied.Mitochondrial DNA sequence of 3 patients showed mtDNA A3243G transgenation.Conclusion The DWI,MRS and ASL sequences show good ability in MELAS diagnosis and differential diagnosis.

Brain white matter structure changes on acute phase of the posttraumatic stress disorder patients-a diffusion tensor imaging study / 实用放射学杂志

Objective To detect the changes of the brain white matter microstructure at the acute stage of posttraumatic stress disorder(PTSD)resulting from a single,extreme and long-lasting trauma.Methods DTI scans were performed on 1 7 survivors of coal mine disaster(PTSD group)and 1 7 cases of normal control(control group).The differences of the mean diffusivity(MD)values measured from the whole brain DTI between the two groups were analyzed based on tract based spatial statistics (TBSS).MD data were statistically compared between the two groups based on nonparametric random permutation test(RPT),and the brain areas of significant differences between the two groups were obtained.Results Compared with the control group,MD values were increased in the bilateral rostral corpus callosum body and left precorona radiata,and decreased in the bilateral superior and posterior corona ra-diate,posterior limb of the left internal capsule,left cerebral peduncle and left thalamic.The differences were statistically significant (P <0.01 TFCE-corrected).Conclusion TBSS is a comprehensive and accurate method for evaluate the changes of brain white mat-ter in PTSD cases.TBSS can provide an objective basis of the pathological brain neural structures imaging for early diagnosis and in-tervention of PTSD.