应用全身体光子计数探测器 CT 对尿石成分进行特征分析。
Characterization of Urinary Stone Composition by Use of Whole-body, Photon-counting Detector CT.
机构信息
Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905.
Institut für Informatik, Technische Universität München, Garching bei München, Germany.
出版信息
Acad Radiol. 2018 Oct;25(10):1270-1276. doi: 10.1016/j.acra.2018.01.007. Epub 2018 Feb 14.
RATIONAL AND OBJECTIVES
This study aims to investigate the performance of a whole-body, photon-counting detector (PCD) computed tomography (CT) system in differentiating urinary stone composition.
MATERIALS AND METHODS
Eighty-seven human urinary stones with pure mineral composition were placed in four anthropomorphic water phantoms (35-50 cm lateral dimension) and scanned on a PCD-CT system at 100, 120, and 140 kV. For each phantom size, tube current was selected to match CTDI (volume CT dose index) to our clinical practice. Energy thresholds at [25, 65], [25, 70], and [25, 75] keV for 100, 120, and 140 kV, respectively, were used to generate dual-energy images. Each stone was automatically segmented using in-house software; CT number ratios were calculated and used to differentiate stone types in a receiver operating characteristic (ROC) analysis. A comparison with second- and third-generation dual-source, dual-energy CT scanners with conventional energy integrating detectors (EIDs) was performed under matching conditions.
RESULTS
For all investigated settings and smaller phantoms, perfect separation between uric acid and non-uric acid stones was achieved (area under the ROC curve [AUC] = 1). For smaller phantoms, performance in differentiation of calcium oxalate and apatite stones was also similar between the three scanners: for the 35-cm phantom size, AUC values of 0.76, 0.79, and 0.80 were recorded for the second- and third-generation EID-CT and for the PCD-CT, respectively. For larger phantoms, PCD-CT and the third-generation EID-CT outperformed the second-generation EID-CT for both differentiation tasks: for a 50-cm phantom size and a uric acid/non-uric acid differentiating task, AUC values of 0.63, 0.95, and 0.99 were recorded for the second- and third-generation EID-CT and for the PCD-CT, respectively.
CONCLUSION
PCD-CT provides comparable performance to state-of-the-art EID-CT in differentiating urinary stone composition.
目的
本研究旨在探讨全身体光子计数探测器（PCD） CT 系统在鉴别尿路结石成分方面的性能。
材料与方法
将 87 个人类尿路结石置于 4 个仿体水模（35-50cm 侧径）中，并在 PCD-CT 系统上于 100、120 和 140kV 下进行扫描。对于每个体模尺寸，选择管电流以使容积 CT 剂量指数（CTDIvol）与我们的临床实践相匹配。分别使用 25、65、70 和 75keV 的能量阈值生成双能图像。使用内部软件自动对每个结石进行分割；计算 CT 值比，并在受试者工作特征（ROC）分析中用于鉴别结石类型。在匹配条件下，与第二代和第三代双源、双能 CT 扫描仪（使用常规能量积分探测器（EID））进行比较。
结果
在所有研究的设置和较小的体模中，尿酸和非尿酸结石之间实现了完美分离（ROC 曲线下面积（AUC）=1）。对于较小的体模，三种扫描仪在鉴别草酸钙和磷灰石结石方面的性能也相似：对于 35cm 体模尺寸，第二代和第三代 EID-CT 以及 PCD-CT 的 AUC 值分别为 0.76、0.79 和 0.80。对于较大的体模，PCD-CT 和第三代 EID-CT 在这两项鉴别任务中均优于第二代 EID-CT：对于 50cm 体模尺寸和尿酸/非尿酸鉴别任务，第二代和第三代 EID-CT 以及 PCD-CT 的 AUC 值分别为 0.63、0.95 和 0.99。
结论
PCD-CT 在鉴别尿路结石成分方面与最先进的 EID-CT 具有相当的性能。
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