Uhrig Monika, Simons David, Kachelrieß Marc, Pisana Francesco, Kuchenbecker Stefan, Schlemmer Heinz-Peter
Department of Radiology, German Cancer Research Center (DKFZ) Heidelberg, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany.
Department of Medical Physics in Oncology, Division of X-Ray Imaging and Computed Tomography, German Cancer Research Center (DKFZ) Heidelberg, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany.
Cancer Imaging. 2016 Jun 21;16(1):15. doi: 10.1186/s40644-016-0073-5.
Dual energy CT (DECT) has proven its potential in oncological imaging. Considering the repeated follow-up examinations, radiation dose should not exceed conventional single energy CT (SECT). Comparison studies on the same scanner with a large number of patients, considering patient geometries and image quality, and exploiting full potential of SECT dose reduction are rare. Purpose of this retrospective study was to compare dose of dual source DECT versus dose-optimized SECT abdominal imaging in clinical routine.
One hundred patients (62y (±14)) had either contrast-enhanced SECT including automatic voltage control (44) or DECT (56). CT dose index (CTDIvol), size-specific dose-estimate (SSDE) and dose-length product (DLP) were reported. Image noise (SD) was recorded as mean of three ROIs placed in subcutaneous fat and normalized to dose by [Formula: see text] . For dose-normalized contrast-to-noise ratio (CNRD), mean attenuation of psoas muscle (CTmuscle) and subcutaneous fat (CTfat) were compared by CNRD = (CTmuscle - CTfat)/SDn. Statistical significance was tested with two-sided t-test (α = 0.05).
There was no significant difference (p < 0.05) between DECT and SECT: Mean CTDIvol was 14.2 mGy (±3.9) (DECT) and 14.3 mGy (±4.5) (SECT). Mean DLP was 680 mGycm (±220) (DECT) and 665 mGycm (±231) (SECT). Mean SSDE was 15.7 mGy (±1.9) (DECT) and 16.1 mGy (±2.5) (SECT). Mean SDn was 42.2 (±13.9) HU [Formula: see text] (DECT) and 47.8 (±14.9) HU [Formula: see text] (SECT). Mean CNRD was 3.9 (±1.3) [Formula: see text]. (DECT) and 4.0 (±1.3) [Formula: see text] (SECT).
Abdominal DECT is feasible without increasing radiation dose or deteriorating image quality, even compared to dose-optimized SECT including automatic voltage control. Thus DECT can contribute to sophisticated oncological imaging without dose penalty.
双能量CT（DECT）已在肿瘤成像中展现出其潜力。考虑到需要进行重复的随访检查，其辐射剂量不应超过传统的单能量CT（SECT）。在同一台扫描仪上，针对大量患者，综合考虑患者体型和图像质量，并充分发挥SECT剂量降低潜力的对比研究较为少见。这项回顾性研究的目的是比较临床常规中双源DECT与剂量优化后的SECT腹部成像的剂量。
100名患者（62岁（±14岁））分别接受了包括自动电压控制的对比增强SECT（44例）或DECT（56例）检查。报告了CT剂量指数（CTDIvol）、体型特异性剂量估计值（SSDE）和剂量长度乘积（DLP）。图像噪声（SD）记录为放置在皮下脂肪中的三个感兴趣区的平均值，并通过[公式：见原文]进行剂量归一化。对于剂量归一化对比噪声比（CNRD），通过CNRD =（腰大肌CT值（CTmuscle）-皮下脂肪CT值（CTfat））/SDn来比较腰大肌和皮下脂肪的平均衰减值。采用双侧t检验（α = 0.05）进行统计学显著性检验。
DECT和SECT之间无显著差异（p < 0.05）：平均CTDIvol为14.2 mGy（±3.9）（DECT）和14.3 mGy（±4.5）（SECT）。平均DLP为680 mGy·cm（±220）（DECT）和665 mGy·cm（±231）（SECT）。平均SSDE为15.7 mGy（±1.9）（DECT）和16.1 mGy（±2.5）（SECT）。平均SDn为42.2（±13.9）HU [公式：见原文]（DECT）和47.8（±14.9）HU [公式：见原文]（SECT）。平均CNRD为3.9（±1.3）[公式：见原文]（DECT）和4.0（±1.3）[公式：见原文]（SECT）。
腹部DECT是可行的，即使与包括自动电压控制的剂量优化后的SECT相比，也不会增加辐射剂量或降低图像质量。因此，DECT可有助于进行复杂的肿瘤成像且不会增加剂量负担。
