A Technique to Identify Isoattenuating Gallstones with Dual-Layer Spectral CT: An ex Vivo Phantom Study.
A Technique to Identify Isoattenuating Gallstones with Dual-Layer Spectral CT: An ex Vivo Phantom Study.
复制标题
使用双层能谱 CT 识别等衰减胆结石的技术：体外模型研究。
DOI：
10.1148/radiol.2019190083
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发表时间：
2019
期刊：
影响因子：
19.7
通讯作者：
J. Leyendecker
中科院分区：
文献类型：
--
作者：
T. Soesbe;M. Lewis;Y. Xi;T. Browning;L. Ananthakrishnan;J. Fielding;R. Lenkinski;J. Leyendecker
背景以前报道的双能CT方法检测非钙化的胆结石的准确性降低胆结石小于9毫米。目的开发一种双能CT方法区分等衰减胆结石从胆汁，并比较它与以前报道的双能CT方法通过使用前瞻性离体体幻影阅读器的研究。材料与方法从2017年5月至2018年5月，从105名接受胆囊切除术的患者（34名男性;平均年龄，51岁;年龄范围，18-84岁）中收集胆结石，并将其置于含有牛胆汁的120 mL小瓶中。将小瓶放置在充满水的体模内，并使用双层双能量CT进行扫描。评价了30个等衰减胆结石（直径4.3-24.7 mm）。传统的CT图像，虚拟的非对比图像，并在200和40 keV的单能图像。通过使用康普顿和光电衰减的二维直方图创建分割图像。6名阅片者评价了每张图像中等衰减胆结石的存在。使用一致性百分比测量阅片者内和阅片者间一致性，使用受试者工作特征曲线（AUC）估计值和成对比较评估诊断性能，使用Bland-Altman分析比较病理检查时测量的胆石大小与分割图像上测量的胆石大小的一致性。结果对于所有胆结石，分割图像提供了所有阅片者和阅读会话的最高平均阅片者内（88.1%）和阅片者间（88.2%和93.6%）一致性以及最高的总体AUC（0.99; 95%置信区间[CI]：0.97，1.00;所有校正P <0.02）。对于大于9 mm的胆结石，分段AUC和单能AUC之间无显著差异（所有P > 0.94，所有校正P > 0.05）。对于尺寸为9 mm或更小的胆结石，分割图像的总体AUC最高（0.99; 95%CI：0.97，1.00;所有调整后的P <0.01）。结石大小的平均差异为-0.6 mm，与协议的限制从2.6到-3.8 mm。结论从康普顿和光电衰减系数分割图像提高检测等衰减胆结石相比，以前报道的双能量CT方法。© RSNA，2019可为本文提供在线补充材料。另见马托斯在本期的社论。
Background Previously reported dual-energy CT methods for detecting noncalcified gallstones have reduced accuracy for gallstones smaller than 9 mm. Purpose To develop a dual-energy CT method for differentiating isoattenuating gallstones from bile and compare it with previously reported dual-energy CT methods by using a prospective ex vivo phantom reader study. Materials and Methods From May 2017 to May 2018, gallstones were collected from 105 patients (34 men; mean age, 51 years; age range, 18-84 years) undergoing cholecystectomy and placed inside 120-mL vials containing ox bile. The vials were placed inside a water-filled phantom and were scanned with dual-layer dual-energy CT. Thirty isoattenuating gallstones (4.3-24.7 mm in diameter) were evaluated. Conventional CT images, virtual noncontrast images, and monoenergetic images at 200 and 40 keV were created. Segmented images were created by using a two-dimensional histogram of Compton and photoelectric attenuation. Six readers evaluated the presence of isoattenuating gallstones in each image. Intra- and interreader agreement was measured by using percentage agreement, diagnostic performance was evaluated by using mean area under the receiver operating characteristic curve (AUC) estimates and pairwise comparisons, and the agreement of gallstone sizes measured at pathologic examination with those measured on segmented images was compared by using Bland-Altman analysis. Results For all gallstones, segmented images provided the highest mean intrareader (88.1%) and interreader (88.2% and 93.6%) agreements for all readers and reading sessions and the highest overall AUC (0.99; 95% confidence interval [CI]: 0.97, 1.00; adjusted P < .02 for all). For gallstones larger than 9 mm, no significant difference was found between the segmented and monoenergetic AUCs (all P > .94, adjusted P > .05 for all). For gallstones measuring 9 mm or smaller, the segmented images had the highest overall AUC (0.99; 95% CI: 0.97, 1.00; adjusted P < .01 for all). The mean difference in stone sizes was -0.6 mm, with limits of agreement from 2.6 to -3.8 mm. Conclusion Segmented images from Compton and photoelectric attenuation coefficients improve detection of isoattenuating gallstones compared with previously reported dual-energy CT methods. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Matos in this issue.