不同b值条件下心脏体素内不相干运动成像相关参数的一致性

Consistency of intravoxel incoherent motion diffusion imaging of mycardium with different b-value condition

目的观察不同b值条件下心脏体素内不相干运动(IVIM)成像相关参数的一致性。方法对30名健康志愿者行左心室中间部IVIM扫描,以双指数模型获取IVIM参数值慢速表观弥散系数(ADCslow)、快速ADC(ADCfast)及灌注分数f。比较9个b值(0、20、50、80、100、120、200、300、500 s/mm^2)与7个b值(0、20、80、100、200、300、500 s/mm^2)条件下所测参数值的差异,采用组内相关系数(ICC)分析2名医师测量参数结果的一致性,以Bland-Altman检验分析不同b值条件下所测参数的一致性。结果9个与7个b值条件下ADCslow、ADCfast及f差异均无统计学意义(P均>0.05),且2名医师测量IVIM参数的组内及组间一致性均较好(ICC均≥0.66,P均<0.05)。Bland-Altman图显示,9个与7个b值时ADCslow的平均偏差为-0.07×10-3 mm^2/s,一致性界限(-1.87,1.73);ADCfast的平均偏差1.57×10-3 mm^2/s,一致性界限(-72.64,75.77);f的平均偏差1.17%,一致性界限(-13.45,15.79)。结论9个与7个b值条件下心脏IVIM成像各参数值的一致性较好。

Objective To explore the consistency of intravoxel incoherent motion(IVIM)parameters of myocardium with different b-values.Methods IVIM scanning was performed on the middle part of the left ventricle in 30 healthy volunteers.IVIM parameter values,slow apparent diffusion coefficient(ADCslow),fast ADC(ADCfast)and perfusion score f were obtained by using a double-exponential model.The differences of measured parameter values were compared between 9 b values(0,20,50,80,100,120,200,300,500 s/mm^2)and 7 b values(0,20,80,100,200,300,500 s/mm^2).Intraclass correlation coefficient(ICC)test was used to analyze the consistency of parameters measured by two physicians,while Bland-Altman test was used to analyze the consistency of parameters under the condition of 9 b values and 7 b values.Results Under 9 b values and 7 b values,no significant difference of ADCslow,ADCfast nor f was detected within or between groups(all ICC≥0.66,all P<0.05).Bland-Altman diagrams showed that the average deviation of ADCslow between 9 and 7 b values was-0.07×10-3 mm^2/s,consistency limit was(-1.87,1.73),while the mean deviation of ADCfast was 1.57×10-3 mm^2/s,consistency limit was(-72.64,75.77),and the mean deviation of f was 1.17%,consistency limit was(-13.45,15.79).Conclusion IVIM parameters of myocardium had rather good consistency under the condition of 9 and 7 b values.