Objective To investigate the value of motion correction by 3D non-rigid registration in improving the image quality and accuracy of quantitative analysis of dynamic contrast-enhanced (DCE) MRI of the liver.Methods 35 patients with confirmed hepatocellular carcinoma (HCC) were underwent hepatic DCE-MRI with free-breathing.Image motion correction was performed using 3D non-rigid registration.Based on a dual-input Toffs model using the time-concentration curves of abdominal aorta and portal vein as the blood vessel input function (VIF),the quantitative parameters including Ktrans,Kep,Ve,Vp,and HPI of HCC and normal liver parenchyma before and after motion correction were obtained and compared.The maximum area was measured and compared to the original image before and after correction of lesion area difference.Results After 3D motion correction,the time-concentration curves of abdominal aorta and portal vein became smoother with less fluctuation.The Ktrans,Kep,Ve,Vp,and HPI values of HCC after motion correction were higher than those before correction.There were significant differences in Ktrans,Ve,Vp,HPI values before and after motion correction (P＜0.05) whereas the difference between the two Kep and HPI values were not significant (P＞0.05).The values of Ktrans,Ve,and Vp in normal liver parenchyma after motion correction were significantly higher than that before motion correction (P＜0.05).There was no significant difference between the two Kep values (P＞0.05).The original image area before motion correction of HCC was not significantly greater than that after motion correction (P＜0.05).The liver tissue noise was not significantly lower after than that before motion correction (P＞0.05).However,the image qualitative score was significantly higher with motion correction (P＜0.05).Conclusion 3D non-rigid registration can significantly reduce motion artifacts and can improve the accuracy of the quantitative parameters of perfusion in DCE-MRI of the liver.%目的 探讨3D非刚性图像运动校正在提高肝脏DCE-MRI图像质量和定量参数准确性的应用价值.方法 35例确诊肝细胞癌患者进行自由呼吸下全肝MRI灌注扫描,使用3D对比增强非刚性配准对多期动态增强扫描MRI图像进行图像运动配准,利用肝脏双血供模型和腹主动脉、门静脉时间-浓度曲线作为血管输入函数(VIF),分别获得肝癌、肝实质图像运动校正前后灌注参数(Ktrans、Kep、Ve、Vp、HPI).比较图像运动校正前后各组定量参数差异.对运动校正前后图像质量分别进行客观和主观评价.测量病灶最大面积,比较原始图像上校正前后病灶面积的差异.结果 使用3D图像运动校正后腹主动脉、门静脉时间-浓度曲线波动幅度缩小,平滑度更好.图像运动校正后肝癌Ktrans、Kep、Ve、Vp、HPI值均大于校正前,Ktrans、Ve、Vp,值差异存在统计学差异(P＜0.05),Kep值两者间无统计学差异(P＞0.05).图像运动校正后肝实质Ktrans、Kep、Ve、Vp、HPI值均大于校正前,Ktrans、Ve、Vp值差异存在统计学差异(P＜0.05);Kep值两者间无统计学差异(P＞0.05);图像运动校正前后HPI值相近,且无统计学差异(P＞0.05).肝癌在原始图像上面积平均值运动校正前大于运动校正后,但无统计学意义(P＞0.05).校正后肝组织噪声低于矫正前,无统计学意义(P＞0.05),校正后图像主观评分明显高于矫正前,差异存在统计学意义(P＜0.05).结论 3D非刚性运动校正能减少肝脏MRI多期动态增强图像运动伪影,有助于提高灌注定量参数的准确性.
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