Characterization of human renal stones with MDCT: Advantage of dual energy and limitations due to respiratory motion
Characterization of human renal stones with MDCT: Advantage of dual energy and limitations due to respiratory motion
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DOI：
10.2214/ajr.07.2466
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发表时间：
2008-03-01
影响因子：
5
通讯作者：
Hubert, Jacques
中科院分区：
文献类型：
--
作者：
Grosjean, Romain;Sauer, Benoit;Hubert, Jacques
目标。我们的目的是利用CT衰减值确定放置在果冻幻影中的241例人类肾结石的化学成分，并分析呼吸运动对分类的影响。材料和方法。将结石放入模拟肾脏x射线衰减的果冻中。动态平台应用于幻体自由呼吸运动（z轴正弦运动）和缺乏维持屏气（z轴5 mm中心点s(-1)）的运动。化学成分的测定采用80和120 kV的CT平均衰减值和双能CT衰减值。241个人类尿路结石被分为6组：尿酸结石、胱氨酸结石、鸟粪石结石、二水合草酸钙结石、一水合草酸钙结石和刷石结石。在没有运动的情况下，双重能量的使用使所有类型的结石的分化具有统计学上的显著差异。尿酸（-20 +/- 22 H）、胱氨酸（106 19 H）、鸟粪石（271 16 H）、weddellite （323 5 H）、刷石（415 30 H）和whewellite （510 17 H）被确定为不同的类群。运动引起的CT平均衰减值与无运动时的衰减值有显著差异。随着运动，双能CT衰减值不能区分所有结石类型。双能CT衰减值可用于体外预测结石的化学成分。然而，当在图像采集过程中对肾结石进行轻微运动时，其值与没有运动时的值显着不同。因此，在区分石头类型时产生了混淆。为了在体内使用衰减值来辨别结石类型，必须进行完美的屏气。
OBJECTIVE. Our aim was to determine, using CT attenuation values, the chemical composition of 241 human renal stones placed in a jelly phantom and to analyze the influence of respiratory motion on the classification.MATERIALS AND METHODS. The stones were placed in a jelly simulating the X-ray attenuation of the kidneys. A dynamic platform was used to apply to the phantom free-breathing motion (sinusoidal motion in z-axis) and motion due to lack of maintenance of a breath-hold (5 mm center dot s(-1) in z-axis). Determination of the chemical composition was performed with mean CT attenuation values obtained at 80 and 120 kV and with dual-energy CT attenuation values.RESULTS. Two hundred forty-one human urinary stones were classified into six groups: uric acid, cystine, struvite, weddellite (calcium oxalate dihydrate), whewellite (calcium oxalate monohydrate), and brushite. With no motion, the use of dual energy enabled differentiation of all of the types of stones with statistically significant differences. Uric acid (-20 +/- 22 H), cystine (106 19 H), struvite (271 16 H), weddellite (323 5 H), brushite (415 30 H), and whewellite (510 17 H) were identified as distinct groups. Motion-induced mean CT attenuation values were significantly different from those obtained with no motion. With motion, dual-energy CT attenuation values did not allow differentiation of all stone types.CONCLUSION. Dual-energy CT attenuation values can be used to predict the chemical composition of stones in vitro. However, when slight motion is applied to renal stones during image acquisition, the values become significantly different from those obtained with no motion. Consequently, confusion arises in differentiating stone types. A perfect breath-hold has to be performed for in vivo use of attenuation value to discern stone type.