Piskunowicz Maciej, Hofmann Lucie, Zuercher Emilie, Bassi Isabelle, Milani Bastien, Stuber Matthias, Narkiewicz Krzysztof, Vogt Bruno, Burnier Michel, Pruijm Menno
Department of Nephrology and Hypertension, CHUV, Lausanne, Switzerland; Department of Radiology, Medical University of Gdansk, Gdansk, Poland.
Department of Nephrology and Hypertension, Bern University Hospital, Bern, Switzerland.
Magn Reson Imaging. 2015 Apr;33(3):253-61. doi: 10.1016/j.mri.2014.12.002. Epub 2014 Dec 15.
To assess inter-observer variability of renal blood oxygenation level-dependent MRI (BOLD-MRI) using a new method of analysis, called the concentric objects (CO) technique, in comparison with the classical ROI (region of interest)-based technique.
MR imaging (3T) was performed before and after furosemide in 10 chronic kidney disease (CKD) patients (mean eGFR 43±24ml/min/1.73m(2)) and 10 healthy volunteers (eGFR 101±28ml/min1.73m(2)), and R2* maps were determined on four coronal slices. In the CO-technique, R2* values were based on a semi-automatic procedure that divided each kidney in six equal layers, whereas in the ROI-technique, all circles (ROIs) were placed manually in the cortex and medulla. The mean R2*values as assessed by two independent investigators were compared.
With the CO-technique, inter-observer variability was 0.7%-1.9% across all layers in non-CKD, versus 1.6%-3.8% in CKD. With the ROI-technique, median variability for cortical and medullary R2* values was 3.6 and 6.8% in non-CKD, versus 4.7 and 12.5% in CKD; similar results were observed after furosemide.
The CO-technique offers a new, investigator-independent, highly reproducible alternative to the ROI-based technique to estimate renal tissue oxygenation in CKD.
使用一种名为同心物体（CO）技术的新分析方法，评估肾血氧水平依赖性功能磁共振成像（BOLD-MRI）的观察者间变异性，并与传统的基于感兴趣区（ROI）的技术进行比较。
对10例慢性肾脏病（CKD）患者（平均估算肾小球滤过率[eGFR]为43±24ml/min/1.73m²）和10名健康志愿者（eGFR为101±28ml/min/1.73m²）在使用速尿前后进行磁共振成像（3T）检查，并在四个冠状面上确定R2图。在CO技术中，R2值基于一种半自动程序，该程序将每个肾脏分为六个相等的层面，而在ROI技术中，所有圆形（ROI）均手动放置在皮质和髓质中。比较两位独立研究者评估的平均R2*值。
使用CO技术时，非CKD患者所有层面的观察者间变异性为0.7%-1.9%，而CKD患者为1.6%-3.8%。使用ROI技术时，非CKD患者皮质和髓质R2*值的中位变异性分别为3.6%和6.8%，CKD患者分别为4.7%和12.5%；使用速尿后观察到类似结果。
CO技术为基于ROI的技术提供了一种新的、独立于研究者的、高度可重复的替代方法，用于评估CKD患者的肾组织氧合。
