肾功能：肝硬化患者的磁共振肾图测量肾小球滤过率。
Kidney function: glomerular filtration rate measurement with MR renography in patients with cirrhosis.
机构信息
Department of Radiology, NYU Langone Medical Center, New York, NY, USA.
出版信息
Radiology. 2011 May;259(2):462-70. doi: 10.1148/radiol.11101338. Epub 2011 Mar 8.
PURPOSE
To assess the accuracy of glomerular filtration rate (GFR) measurements obtained with low-contrast agent dose dynamic contrast material-enhanced magnetic resonance (MR) renography in patients with liver cirrhosis who underwent routine liver MR imaging, with urinary clearance of technetium 99m ((99m)Tc) pentetic acid (DTPA) as the reference standard.
MATERIALS AND METHODS
This HIPAA-compliant study was institutional review board approved. Written informed patient consent was obtained. Twenty patients with cirrhosis (14 men, six women; age range, 41-70 years; mean age, 54.6 years) who were scheduled for routine 1.5-T liver MR examinations to screen for hepatocellular carcinoma during a 6-month period were prospectively included. Five-minute MR renography with a 3-mL dose of gadoteridol was performed instead of a routine test-dose timing examination. The GFR was estimated at MR imaging with use of two kinetic models. In one model, only the signal intensities in the aorta and kidney parenchyma were considered, and in the other, renal cortical and medullary signal intensities were treated separately. The GFR was also calculated by using serum creatinine levels according to the Cockcroft-Gault and modification of diet in renal disease (MDRD) formulas. All patients underwent a (99m)Tc-DTPA urinary clearance examination on the same day to obtain a reference GFR measurement. The accuracies of all MR- and creatinine-based GFR estimations were compared by using Wilcoxon signed rank tests.
RESULTS
The mean reference GFR, based on (99m)Tc-DTPA clearance, was 74.9 mL/min/1.73 m(2) ± 27.7 (standard deviation) (range, 10.3-120.7 mL/min/1.73 m(2)). With both kinetic models, 95% of MR-based GFRs were within 30% of the reference values, whereas only 40% and 60% of Cockcroft-Gault- and MDRD-based GFRs, respectively, were within this range. MR-based GFR estimates were significantly more accurate than creatinine level-based estimates (P < .001).
CONCLUSION
GFR assessment with MR imaging, which outperformed the Cockcroft-Gault and MDRD formulas, adds less than 10 minutes of table time to a clinically indicated liver MR examination without ionizing radiation.
SUPPLEMENTAL MATERIAL
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101338/-/DC1.
目的
以应用放射性核素 99mTc 五亚甲基二膦酸盐（99mTc-DTPA）清除率作为参考标准，评估在因筛查肝细胞癌而接受常规肝脏磁共振成像检查的肝硬化患者中，应用小剂量对比剂行动态对比增强磁共振（MR）肾成像获得的肾小球滤过率（GFR）测量的准确性。
材料与方法
本研究符合 HIPAA 规定，经机构审查委员会批准，患者均签署书面知情同意书。前瞻性纳入 2012 年 6 月期间因筛查肝细胞癌而在我院接受常规 1.5T 肝脏 MR 检查的 20 例肝硬化患者（14 名男性，6 名女性；年龄 41~70 岁，平均年龄 54.6 岁）。行 5 分钟低剂量（3mL）钆喷替酸葡甲胺动态对比增强 MR 肾成像，代替常规测试剂量时间检查。应用两种动力学模型在 MR 图像上估算 GFR。在一种模型中，仅考虑主动脉和肾实质的信号强度，而在另一种模型中，分别处理肾皮质和髓质的信号强度。同时还根据 Cockcroft-Gault 和肾脏病饮食改良公式（MDRD）计算血清肌酐水平得出的 GFR。所有患者于同日行 99mTc-DTPA 尿清除率检查，获得参考 GFR 测量值。应用 Wilcoxon 符号秩检验比较所有基于 MR 和基于肌酐的 GFR 估计的准确性。
结果
基于 99mTc-DTPA 清除率的平均参考 GFR 为 74.9 mL/min/1.73 m²±27.7（标准差）（范围，10.3~120.7 mL/min/1.73 m²）。对于两种动力学模型，95%的基于 MR 的 GFR 值与参考值相差 30%以内，而基于 Cockcroft-Gault 和 MDRD 的 GFR 值分别只有 40%和 60%在这一范围内。基于 MR 的 GFR 估计值明显比基于肌酐的估计值更准确（P＜.001）。
结论
MR 成像评估 GFR 优于 Cockcroft-Gault 和 MDRD 公式，在无需电离辐射的情况下，在临床需要的肝脏 MR 检查中增加不到 10 分钟的检查时间。
补充材料
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101338/-/DC1.
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