Institute of Diagnostic and Interventional Radiology, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
Institute of Diagnostic and Interventional Radiology, University of Bonn, Bonn, Germany.
Abdom Radiol (NY). 2018 Mar;43(3):742-750. doi: 10.1007/s00261-017-1241-1.
We aimed to determine optimal window settings for poly-energetic (PolyE) and virtual mono-energetic images (MonoE) derived from abdominal angiographic studies on a novel dual-layer spectral detector CT (SDCT) system.
From 50 patients, SDCT datasets PolyE and MonoE at 70 and 40 keV levels were reconstructed and best individual window width and level (BI-W/L) manually assessed. Through regression analysis, the so-called optimized individual (OI-W/L) values were obtained. Subjective image quality parameters and vessel diameters were measured to determine influences of different W/L settings.
Image noise was lower and attenuation and contrast-to-noise ratio were higher in MonoE compared to PolyE (all p ≤ 0.002). Mean BI-W/L values for PolyE, 70, and 40 keV were 637/284, 647/291, and 1568/691, respectively. Mean OI-W/L values were 631/276, 628/286, and 1516/667, respectively. Compared to standard settings, all adjusted W/L settings varied significantly and yielded higher subjective scoring. No between-group differences were found between manually adjusted and mathematically calculated W/L settings.
PolyE and MonoE from abdominal angiographic SDCT studies require appropriate W/L settings especially at low energy reconstruction levels. Individual adjustment reaches the best image quality but is time consuming. From our data, predefined W/L settings of 640/280 (PolyE/MonoE 70 keV) and 1570/690 (MonoE 40 keV) as a non-individualized starting point for abdominal angiographic studies from the novel SDCT system are suggested.
我们旨在确定新型双层能谱探测器 CT（SDCT）系统腹部血管造影研究中多能量（PolyE）和虚拟单能量（MonoE）图像的最佳窗宽和窗位设置。
从 50 名患者中，重建 SDCT 数据集的 PolyE 和 MonoE 在 70keV 和 40keV 水平，并手动评估最佳个体窗宽和窗位（BI-W/L）。通过回归分析，得到所谓的优化个体（OI-W/L）值。测量主观图像质量参数和血管直径，以确定不同 W/L 设置的影响。
与 PolyE 相比，MonoE 的图像噪声更低，衰减和对比噪声比更高（均 p≤0.002）。PolyE、70keV 和 40keV 的平均 BI-W/L 值分别为 637/284、647/291 和 1568/691。平均 OI-W/L 值分别为 631/276、628/286 和 1516/667。与标准设置相比，所有调整后的 W/L 设置均有显著差异，主观评分更高。手动调整和数学计算的 W/L 设置之间没有组间差异。
腹部血管造影 SDCT 研究中的 PolyE 和 MonoE 需要适当的 W/L 设置，尤其是在低能量重建水平下。个体调整可获得最佳图像质量，但耗时。根据我们的数据，建议将 640/280（PolyE/MonoE 70keV）和 1570/690（MonoE 40keV）作为新型 SDCT 系统腹部血管造影研究的非个体化起点的预设 W/L 设置。
