| Part one:Application value of MRI 3D-DESS sequence in carpal tunnel: quantitative anatomy of the median nerve in healthy young peopleObjective To investigate the MRI anatomical parameters of the median nerve in the carpal tunnel of healthy young people,and to provide evidence for the diagnosis of carpal tunnel syndrome(CTS).Methods 25 cases of young healthy volunteers were underwent conventional 3.0T magnetic resonance 3D Double-Echo Steady-State sequence scanning of the non-dominant wrist.Cross-sectional area of the median nerve at distal radius plane(CSA1)and lentiform bone plane(CSA2)were measured.The median nerve swelling rate(MNSR),the median nerve flattening rate(MNFR),and the transverse carpal ligament bow rate(FRAR)were calculated.A correlation analysis between general situation comprising age,wrist circumference and BMI,and measured statistics including CSA1,CSA2,MNSR,MNFR,FRAR were conducted and the 95% confidence interval of all data were calculated.Results In the 3D Double-Echo Steady-State sequence the median nerve demonstrated slightly high signal intensity,the tendons within the carpal tunnel revealed low signal intensity.Synovial tissue of carpal tunnel displayed moderate signal intensity.Boundary of the median nerve is clear,with enough contrast with surrounding structures.The average value of CSA1,CSA2 was 8.34±1.46mm2,9.40±1.97mm2 respectively.The average value of MNSR,MNFR,FRAR was 1.13±0.18,2.41±0.73,0.06±0.02 respectively.There was a statistically significant positive correlation between MNFR and wrist circumference,as well as MNFR and BMI.However,no significant correlations were found between MNFR and age.It was significant that the negative correlation between CSA1 and wrist circumference.No statistically correlation was found between MNSR,FRAR,CSA2,age,wrist circumference and BMI.Conclusion The 3D Double-Echo Steady-State sequence,which provide abundant and accurate diagnosing information in the measurement of the median nerve,plays an important role in the early diagnosis of carpal tunnel syndrome.Part two:Quantitative analysis of the median nerve in the carpal tunnel of healthy volunteers by using DTI and DTT at 3T MRObjective Quantitative analyze the median nerve by using diffusion tensor imaging(DTI)and rebuild it by diffusion tensor tractography(DTT)in young healthy volunteers.Methods A total of 25 healthy young volunteers underwent DTI scanning at 3T MR.DTI parameters(including FA,ADC,E1,E2,E3 values)were quantified.AD,RD values and mean values of FA,AD,RD,ADC were calculated respectively.Differences among FA,AD,RD,ADC and E1,E2,E3 values of different planes were compared with ANOVA test.Line graphs mapping the proximal-to-distal course of median nerve DTI parameters and the 95% confidence interval of all data were calculated.The median nerve was visualized with tractography.Results(1)Mean values of FA,AD,RD,ADC were respectively,0.686±0.089,2.085±0.263,0.568±0.151,1.073±0.140.(2)Significant statistic differences were found between FA,RD values of different planes(the F value were 5.126,2.508 and the P value were 0.000,0.009 respectively)and there was no statistically significant difference among AD,ADC,E1,E2 and E3 values of different planes(the F value were 1.297,0.816,1.297,0.494,0.494 and the P value were 0.239,0.602,0.239,0.878,0.878 respectively).(3)The FA and AD profiles presented an approximate declining curve,while RD profile presented an increasing trend.The RD and FA profile appeared inverted tendency.The extreme values of them were at-28 mm and 8mm.There was no explicit tendency of ADC profile.(4)The 95% confidence interval of MNFA,MNAD,MNRD,MNADC were 0.675~0.698,2.052~2.117,0.549~0.587,1.056~1.091 respectively.(5)An complete structure of median nerve can be visualized by using DTT and the distal branches can also be visualized clearly.Conclusion DTI and DTT are useful tools to reconstruct median nerve and provide quantitative information for the diagnosis of median nerve diseases. |
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