Reproducibility of intravoxel incoherent motion in body DWI technique for normal lumbar disc scanning / 实用放射学杂志

ABSTRACT

Objective To investigate the reproducibility of magnetic resonance intravoxel incoherent motion in body diffusionG weighted imaging (IVIMGDWI)for normal lumbar disc scanning.Methods 50 healthy volunteers were enrolled with informed consent,30 males and 20 females,2 5.20±2.04 years old.Using 3.0T MR on the lumbar spine,the sagittal T1 WI,the sagittal,axial T2 WI and sagittal IVIMGDWI sequences were scanned once,then the second sagittal IVIMGDWI sequence was scanned after 4 hours.The IVIMGDWI sequence used 10 b values (0,10,20,40,60,80,100,200,400,600 s/mm2 ).The discs were graded according to the Pfirrmann grading standard.The ADCfast ,ADCslow ,and f values of each intervertebral disc were measured by two doctors at the postGprocessing workstation.Paired tGtest was used to analyze whether there was a difference between the two scans.The intraGgroup correlation coefficient (ICC)was used to analyze the consistency of the ADCfast ,ADCslow ,and f values of the two acquisitions (P＜0.05)and the consistency of the ADCfast ,ADCslow,and f values between the different doctors (P＜0.05).The IVIMGDWI imaging was evaluated to measure the repeatability of normal lumbar discs. Results Of the 50 healthy volunteers,230 intervertebral discs matched the criteria(Pfirrmann gradeⅠandⅡ).The ADCslowvalue between the two scans was significantly different (t＝2.460,P＜0.05),and the differences in ADCfast and f values were not significant (t＝－0.418,1.273,P＞0.05). The consistency of ADCfast ,ADCslow ,and f values for the two scans were generally (ICC＝0.478,0.306,0.316,P＜0.05 ).Different observers had good consistency in the measurement of interverG tebral disc ADCfast ,ADCslow,and f values (ICC＝0.929,0.909, 0.9 1 1 ,P＜0.05).Conclusion The IVIMGDWI imaging has good consistency in the measurement of normal lumbar disc between different observers.The consistency of IVIMGDWI in two scans of normal lumbar intervertebral discs is general,which may be due to the time interval between the two scans.Because ADCslow represents the diffusion of water molecules in tissues,the microenvironment in the lumbar intervertebral disc has changed,resulting in the difference of ADCslow value.As for the problem that different scanning time may lead to the change of IVIMGDWI data,we will study it further.