Application Of MRI Double Reverse Sequence In Ehite Matter Lesions Of The Brain

ObjectiveThe object of this reasearch is to demonstrate the advantages of double reverse transcription sequence(DIR)by comparing with the traditional fluid attenuated inversion recovery(T2-FLAIR)sequence in showing white matter lesions(WML)on image and differences of signal between brain gray matter and white matter both in the WML group and control group.Methods 1.subjectsThe study include 60 cases,which were admissioned in Shandong Medical Imaging Research Institute between 2016.03-2016.11.The 60 cases were divided into WML group and control group,there were 12 males and 18 females cases in WML group,aged 35 to 75 years,mean(49.4 ± 10.1),which were diagnosed as white matter lesion by MRI examination.All the lesions were scattered within the white matter,multiple spots,and patchy.There's no fusion of lesions and the number of lesions can be accurate counted,all patients were no encephalitis,poisoning,metabolic diseases and other medical history,no obvious clinical symptoms,the lesions were all ischemic demyelination due to vascular causes,which can be Basically considered equivalent to leukoaraiosis(LA).30 cases in control group,including 13 males and 17 females,aged 22 to 60 years,mean 37.9 ± 12.2 years old.All of the above subjects' s brain tissue structure were normal,no deformity,brain atrophy,occupying lesions and large area infarction.All subjects have signed informed consent form and recieved includes routine sequences and 3D DIR sequences.2.Apparatus and equipmentUsing Siemens Skyra 3.0T super conducting MRI system,head-neck 8-channel phased array coil.Scanning sequences include: conventional brain scan sequences: sequence of brain brain T1-FLAIR(TR 1820 ms,TE 13 ms,TI 825ms),T2WI(4500ms,TE 100ms),T2-FLAIR(TR 8000 ms,TE 81 ms,TI 2372ms),and sagittal T2WI(TR 5500 ms,TE125ms),the above sequences are 19 layers,layer thickness 5mm,interval 1mm,FOV 230 mm × 230 mm,Sagittal 3D double reverse recovery sequence(DIR),the number of excitation 1,TR 7500 ms,TE 319 ms,layer thickness 1.4 mm,interval 0 mm,layer 144,FOV 230 mm × 230 mm,scan time is 5 minutes and 18 seconds.All images were transmitted to the Siemens skyra workstation.The 3D DIR sequence was reconstructed with MPR as an axial image.The thickness was 5mm,the interval was 1mm,and the number of layers was 19 layers.The reconstructed position was parallel to the brain and as close as possible to the conventional scan sequence.And select the region of interest in the measurement of the intensity of the signal,the selected area of interest as far as possible corresponding to other sequences,the results were statistically analyzed with other sequence results.3.statistical analysisThe differences of white matter signals between FLAIR and DIR sequence were analyzed by SPSS20.0 software,includes the difference of white matter signal between WML group and control group?the lesion signal intensity ratio between two sequences?the number of lesions shown in two sequences.The result of intensity ratio of the selected lesion and the number of lesions showed in both sequences were analyzed by Wilcoxon signed Ranks test because they are of small simple sample and don't conform to the normal distribution.The analyze of remaining data using independent samples T test.ALL the above test were taken P <0.05 was statistically significant.ResultsThe white/gray matter signal intensity ratios showed significant difference(P = 0.000)between the two sequences,the signal intensity of white matter of FLAIR sequence in WML group was significantly higher than control group(P = 0.024)the signal intensity of DIR sequence(P=0.006)is also like this.All the lesions showed obvious high signal on the DIR images,the total number of WML on DIR images were 398,and 239 on FLAIR images,statistically analyzed the result with spss 20.0 software by Wilcoxon signed Ranks test,results show(Z=4.315,P=0.000),and the differences between FLAIR and DIR were significant difference,the signal intensity ratio(SIR)of 100 lesions were measured in the two sequence,the difference was statistically significant(Z=7.877,P=0.000).ConclusionDIR sequence can display more lesions comparing with FLAIR sequence and the white/gray matter signal intensity ratios between two sequence showed significant difference.The DIR sequence can guiding significance for clinical treatment and classification and shows great advantage in the diagnosis of WMLs.