Petritsch Bernhard, Pannenbecker Pauline, Weng Andreas M, Grunz Jan-Peter, Veldhoen Simon, Bley Thorsten A, Kosmala Aleksander
Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany.
Quant Imaging Med Surg. 2021 May;11(5):1817-1827. doi: 10.21037/qims-20-740.
Computed tomography (CT) pulmonary angiography is the diagnostic reference standard in suspected pulmonary embolism (PE). Favorable results for dual-energy CT (DECT) images have been reported for this condition. Nowadays, dual-energy data acquisition is feasible with different technical options, including a single-source split-filter approach. Therefore, the aim of this retrospective study was to investigate image quality and radiation dose of thoracic split-filter DECT in comparison to conventional single-energy CT in patients with suspected PE.
A total of 110 CT pulmonary angiographies were accomplished either as standard single-energy CT with automatic tube voltage selection (ATVS) (n=58), or as split-filter DECT (n=52). Objective [pulmonary artery CT attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)] and subjective image quality [four-point Likert scale; three readers (R)] were compared among the two study groups. Size-specific dose estimates (SSDE), dose-length-product (DLP) and volume CT dose index (CTDIvol) were assessed for radiation dose analysis.
Split-filter DECT images yielded 67.7% higher SNR (27.0 16.1; P<0.001) and 61.9% higher CNR (22.5 13.9; P<0.001) over conventional single-energy images, whereas CT attenuation was significantly lower (344.5 428.2 HU; P=0.013). Subjective image quality was rated good or excellent in 93.0%/98.3%/77.6% (R1/R2/R3) of the single-energy CT scans, and 84.6%/82.7%/80.8% (R1/R2/R3) of the split-filter DECT scans. SSDE, DLP and CTDIvol were significantly lower for conventional single-energy CT compared to split-filter DECT (all P<0.05), which was associated with 26.7% higher SSDE.
In the diagnostic workup of acute PE, the split-filter allows for dual-energy data acquisition from single-source single-layer CT scanners. The existing opportunity to assess pulmonary "perfusion" based on analysis of iodine distribution maps is associated with higher radiation dose in terms of increased SSDE than conventional single-energy CT with ATVS. Moreover, a proportion of up to 3.8% non-diagnostic examinations in the current reference standard test for PE is not negligible.
计算机断层扫描（CT）肺动脉造影是疑似肺栓塞（PE）的诊断参考标准。对于这种情况，双能CT（DECT）图像已报告有良好结果。如今，通过包括单源分体式滤过器方法在内的不同技术选项，双能数据采集是可行的。因此，本回顾性研究的目的是比较疑似PE患者的胸部分体式滤过器DECT与传统单能CT的图像质量和辐射剂量。
总共完成了110例CT肺动脉造影，其中58例采用自动管电压选择（ATVS）的标准单能CT，52例采用分体式滤过器DECT。比较了两个研究组之间的客观指标[肺动脉CT衰减、信噪比（SNR）、对比噪声比（CNR）]和主观图像质量[四点李克特量表；三位阅片者（R）]。评估了大小特异性剂量估计（SSDE）、剂量长度乘积（DLP）和容积CT剂量指数（CTDIvol）以进行辐射剂量分析。
与传统单能图像相比，分体式滤过器DECT图像的SNR高67.7%（27.0±16.1；P<0.001），CNR高61.9%（22.5±13.9；P<0.001），而CT衰减显著更低（344.5±428.2 HU；P=0.013）。单能CT扫描的主观图像质量在93.0%/98.3%/77.6%（阅片者1/阅片者2/阅片者3）中被评为良好或优秀，分体式滤过器DECT扫描的相应比例为84.6%/82.7%/80.8%（阅片者1/阅片者2/阅片者3）。与分体式滤过器DECT相比，传统单能CT的SSDE、DLP和CTDIvol显著更低（所有P<0.05），这与SSDE高26.7%相关。
在急性PE的诊断检查中，分体式滤过器允许从单源单层CT扫描仪获取双能数据。基于碘分布图分析评估肺部“灌注”的现有机会与传统ATVS单能CT相比，在增加SSDE方面会带来更高的辐射剂量。此外，在当前PE参考标准检查中高达3.8%的非诊断性检查比例不可忽视。
