应用体素内不相干运动扩散加权成像评价早期慢性移植肾肾病

目的：探讨应用体素内不相干运动扩散加权成像(intravoxel incoherent motion diffusion weighted imaging，IVIM-DWI)技术无创性评价早期慢性移植肾肾病(chronic allograft nephropathy，CAN)的可行性及临床应用价值。方法：收集符合本研究纳入标准的住院患者23例，其中经病理诊断为早期CAN的患者12例(CAN组)，移植肾肾功能长期稳定的志愿者11例(对照组)。采用多b值DWI序列对移植肾进行磁共振扫描，利用IVIM2b_new软件获取移植肾的IVIM-DWI各定量参数伪彩图及测量肾实质的IVIM-DWI各定量参数值，包括真实扩散系数(D)、灌注相关扩散系数(D*)和灌注分数(f)。采用独立样本t检验对CAN组和对照组的IVIM各定量参数值进行比较，对差异具有统计学意义的指标进行ROC分析，并计算曲线下面积。结果：CAN组的定量参数D值低于对照组，差异具有统计学意义(P<0.05)，两组间D*及f值的差异无统计学意义(P>0.05)。D值鉴别早期CAN的敏感度和特异度分别为58.3%和90.9%，曲线下面积为0.784。 结论：IVIM-DWI的定量参数D能在一定程度上无创性评价早期CAN。IVIM-DWI技术有望成为一种筛查早期CAN的简单有效的无创手段，以协助早期诊断与动态监测CAN。

Application of intravoxel incoherent motion diffusion weighted imaging for assessment of early chronic allograft nephropathy

Objective: To investigate the feasibility and clinical application of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) technique in non-invasive assessment for early chronic allograft nephropathy (CAN). Methods: A total of 23 renal allograft recipients were recruited from inpatients or outpatients according to the inclusion and exclusion criteria for this study. Recipients were divided into a CAN group (n=12, pathologically confirmed early CAN patients) and a control group (n=11, volunteers with long-term stable renal function). Abdominal MRI was performed on patients of renal allograft with a multi-b value DWI sequence. IVIM2b-new software was used for obtaining the IVIM-DWI quantitative parameter pseudo-color maps and the values of IVIM-DWI of renal parenchyma, including the pure diffusion coefficient (D), perfusion correlation diffusion coefficient (D*) and perfusion fraction (f). The IVIM quantitative parameters between the two groups were compared using independent sample t test. ROC analysis was performed when the differences in parameter were statistically significant and the area under curve (AUC) was calculated. Results: In IVIM bi-exponential analysis, The D value was significantly decreased in the CAN group compared with the control group (P<0.05), whereas there are no significantly difference in value of D* and f between the two groups (all P>0.05). The AUC of D value for distinguishing the early CAN from the control were 0.784 with sensitivity and specificity at 58.3% and 90.9%, respectively. Conclusion: The IVIM-DWI quantitative parameter D can non-invasively assess early CAN to some extent. IVIM-DWI technique is expected to be an effective, easy and non-invasive method to detect early CAN, and assist early diagnose as well as dynamically monitor CAN.