肝脏多b值扩散心率因素的评价

目的:评价心电门控技术心率因素对肝脏体素内不相干运动成像(IVIM)图像质量及参数值的影响.方法:选取20名接受心电门控IVIM DWI序列扫描的志愿者,设定6个b值(范围0,50,100,150,300,600s/mm2),按受检者心率分为2组,每组10例,实验组受检者心率≤70次/分,对照组受检者心率≥80次/分.由两名从事腹部MR影像诊断5年以上的高年资医师对所得MR图像进行分析,测量并分析图像SNR、ADC、IVIM各参数值,并对IVIM-DWI图像质量进行评价.结果:实验组所得图像伪影最少,解剖结构清晰,图像质量较高,不同b值时实验组SNR值均大于对照组,两组间差异有统计学意义(P＜0.05).两组ADC、D、D*、f值中,仅肝左叶的ADC值实验组(1.432±0.299)×10-3mm2/s;对照组(1.945±0.543)×10-3 mm2/s]和D值实验组(1.372±0.378)×10-3mm2/s;对照组(1.617±0.361)×10-3mm2/s]在两组间的差异有统计学意义(P值分别为0.000、0.013).结论:肝脏IVIM心电门控成像技术具有重要的临床价值,低心率心电门控IVIM DWI成像可得到较好的图像质量和稳定可靠的参数值.

Effects of heart rate on image quality of liver intravoxel incoherent motion diffusion-weighted imaging with ECG-gating technology

Objective:To investigate the effects of heart rate on image quality of liver intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) with ECG-gating technology.Methods:20 volunteers underwent ECG-gating IVIM-DWI with 6 different b values (0～600s/mm2) at a 1.5T MR scanner and were divided into 2 groups according to the heart rate,and each group had 10 volunteers.The heart rate of the study group subjects was 70 beats per minute or less and of the control group subjects was 80 beats per minute or more.The MR images were analyzed by two senior doctors who were engaged in abdominal MR imaging diagnosis for more than 5 years.The parameters of the images SNR,ADC and IVIM were measured and analyzed,and the IVIM-DWI image quality was evaluated.Results:In the study group,the image artifacts were the least and the anatomical structure was clear.The image quality of study group was higher than that of the control group,and the SNR of the study group was higher than that of the control group at different b values.The difference between the two groups was statistically significant (P＜0.05).In the ADC,D,D * and f values of the two groups,significant inter-group difference was observed only in ADC study group:(1.432±0.299)× 10-3mm2/s;control group:(1.945± 0.543) × 10-3mm2/s] and D study group:(1.372±0.378) × 10-3mm2/s;the control group:(1.617±0.361) × 10-3 mm2/s] (P=0.000、0.013,respectively).Conclusion:The better image quality of IVIM 3DWI can be obtained when controlling the heart rate less than 70 beats per minute during liver intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) with ECG-gating.