Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Siemens Healthcare GmbH, An der Lände 1, 91301, Forchheim, Germany.
Abdom Radiol (NY). 2021 May;46(5):2079-2089. doi: 10.1007/s00261-020-02852-5. Epub 2020 Nov 7.
To compare noise texture and accuracy to differentiate uric acid from non-uric acid urinary stones among four different single-source and dual-source DECT approaches in an ex vivo phantom study.
Thirty-two urinary stones embedded in gelatin were mounted on a Styrofoam disk and placed into a water-filled phantom. The phantom was imaged using four different DECT approaches: (A) dual-source DECT (DS-DE); (B) 1st generation split-filter single-source DECT (SF1-TB); (C) 2nd generation split-filter single-source DECT (SF2-TB) and (D) 2nd generation split-filter single-source DECT using serial acquisitions (SF2-TS). Two different radiation doses (3 mGy and 6 mGy) were used. Noise texture was compared by assessing the average spatial frequency (f) of the normalized noise power spectrum (nNPS). ROC curves for stone classification were computed and the accuracy for different dual-energy ratio cutoffs was derived.
NNPS demonstrated comparable noise texture among A, C, and D (f-range 0.18-0.19) but finer noise texture for B (f = 0.27). Stone classification showed an accuracy of 96.9%, 96.9%, 93.8%, 93.8% for A, B, C, D for low-dose, respectively, and 100%, 96.9%, 96.9%, 100% for routine dose. The vendor-specified cutoff for the dual-energy ratio was optimal except for the low-dose scan in D for which the accuracy was improved from 93.8 to 100% using an optimized cutoff.
Accuracy to differentiate uric acid from non-uric acid stones was high among four single-source and dual-source DECT approaches for low- and routine dose DECT scans. Noise texture differed only slightly for the first-generation split-filter approach.
在一项离体仿体研究中，比较四种不同的单源和双源 DECT 方法中尿酸和非尿酸尿石之间的噪声纹理和准确性。
将 32 颗嵌入明胶的尿石安装在聚苯乙烯泡沫盘上，并放置在充满水的仿体中。使用四种不同的 DECT 方法对仿体进行成像：（A）双源 DECT（DS-DE）；（B）第一代分束滤波单源 DECT（SF1-TB）；（C）第二代分束滤波单源 DECT（SF2-TB）和（D）第二代分束滤波单源 DECT 采用串行采集（SF2-TS）。使用两种不同的辐射剂量（3 mGy 和 6 mGy）。通过评估归一化噪声功率谱（nNPS）的平均空间频率（f）来比较噪声纹理。计算了用于结石分类的 ROC 曲线，并得出了不同双能比截止值的准确性。
NNPS 在 A、C 和 D 之间表现出相似的噪声纹理（f 范围为 0.18-0.19），但 B 的噪声纹理更精细（f=0.27）。对于低剂量扫描，结石分类的准确率分别为 96.9%、96.9%、93.8%、93.8%，对于常规剂量扫描分别为 100%、96.9%、96.9%、100%。除了在 D 中使用优化的截止值将准确率从 93.8%提高到 100%外，双能比的供应商指定截止值是最佳的。
在低剂量和常规剂量 DECT 扫描中，四种单源和双源 DECT 方法均可高度准确地区分尿酸和非尿酸结石。第一代分束滤波方法的噪声纹理仅略有差异。
