基于心电门控技术的体素内不相干运动成像评价正常肝脏图像质量

目的 探讨体素内不相干运动（IVIM）DWI条件下心电门控技术对肝脏图像质量和参数测量的影响。方法 前瞻性收集20名志愿者行IVIM DWI，采用自由呼吸和心电门控扫描，并对所得图像进行主观评分，测量肝左、右叶SNR、ADC值及IVIM各参数值[真扩散系数（D）、假扩散系数（D^*）、灌注分数（f）]。采用Wilcoxon符号秩和检验比较肝脏图像主观质量评分，以配对t检验比较SNR、ADC值及IVIM各参数值，以Bland-Altman方法评价各参数值的一致性。结果 采用心电门控技术所得图像质量主观评分明显高于自由呼吸（P均<0.01）；不同b值时采用心电门控技术测得肝左叶SNR均高于自由呼吸图像（P<0.01），肝左叶ADC、f值均低于自由呼吸图像（P均<0.05），而D值则高于自由呼吸图像（P<0.05）。采用心电门控技术肝左叶D、D^*和f值的一致性好于自由呼吸图像。结论 心电门控IVIM DWI可获得较好的图像质量，有效克服心脏搏动对肝左叶各参数值数据测量的影响。

Evaluation of intravoxel incoherent motion imaging in normal liver based on ECG-triggered technique

Objective To investigate the influence of ECG-triggered technique on imaging quality and parameters in diffusion weighted intravoxel incoherent motion imaging (IVIM DWI). Methods Twenty young healthy volunteers underwent liver IVIM DWI examination were enrolled, the images were obtained with ECG-triggered and free breath, and SNR, ADC and parameters of IVIM (true-diffusion coefficient[D], pseudo-diffusion coefficient[D^*], perfusion fraction[f]) of the left and right lobe of liver were acquired. The scores of liver imaging quality was analyzed with Wilcoxon sign rank sum test. The SNR, ADC, D, D^* and f values were analyzed with paired-samples t test. The consistency of ADC, D, D^*, and f were assessed with the Bland-Altman method. Results The scores of liver imaging quality of ECG-triggered were significantly higher than those of free breath (all P<0.01). Under different b values, SNR of left lobe of liver with ECG-triggered were higher than those of the free breath (all P<0.01). The values of ADC and f of left lobe of liver with ECG-triggered were statistically lower than those of free breath (both P<0.05), but the values of D were higher than that of free breath (P<0.05). The consistency of left lobe of liver with ECG-triggered was better than that with free breath. Conclusion IVIM DWI combined with ECG-triggered can be used to obtain better imaging quality and effectively overcome the interference of heart beating on parameters measuring in left lobe of liver.