Baliyan Vinit, Kordbacheh Hamed, Serrao Jessica, Sahani Dushyant V, Kambadakone Avinash R
From the Department of Radiology, Massachusetts General Hospital, Boston, MA.
J Comput Assist Tomogr. 2018 Nov/Dec;42(6):932-936. doi: 10.1097/RCT.0000000000000804.
Our objective was to evaluate image quality (IQ) and material decomposition in patients with large body habitus undergoing portal venous phase abdominal computed tomography (CT) scans on dual-source dual-energy CT (dsDECT) scanners.
This retrospective analysis included 30 scans from consecutive patients (19 males/11 females, mean ± SD age = 55.3 ± 17.5 years, range = 27-87 years) with large body habitus (≥90 kg, mean ± SD weight = 105.4 ± 12.35, range = 91-145 kg) who underwent portal venous phase abdominal DECT examinations on dsDECT scanner between Jan 2015 and Dec 2015. Qualitative and quantitative evaluation of IQ of DECT data sets (blended, iodine, and virtual noncontrast images) was performed. The patients were categorized into 2 groups (group A, ≤104 kg; group B, >104 kg).
The mean ± SD patient body weight in group A was 97.2 ± 4.5 kg (range = 91-104 kg) and 114.8 ± 11.7 kg (range = 104.3-145.2 kg) for patients in group B. The diagnostic acceptability of the blended images in patients > 104 kg was lower (3.6 vs 4, <3 in 4/14 vs 0/16, P = 0.03). The extension of visceral anatomy beyond DE field of view (DEFOV) was seen in 60% (28 organs in 18 patients), the most common organs being liver and spleen. The incidence of visceral organs outside DEFOV was significantly higher in patients > 104 kg (18 vs 10, P = 0.03). Outside the DEFOV, blended images demonstrated higher image noise (mean: 14.48, range = 10.09-26.83 vs mean: 9.5, range = 7.3-15.8) P < 0.001) and lower signal-to-noise ratio (mean: 4.15, range = 1.5-7.6 vs mean: 7.5, range = 4.2-9.9) P < 0.001), and material-specific information was not available in this region. Within the DEFOV, the IQ of iodine maps and virtual non-contrast images were diagnostically acceptable with diagnostic acceptability of 3 or greater in nearly all patients. A 40-cm transverse diameter cut-off provided a good predictor of extension of visceral anatomy outside the effective DEFOV.
Dual-source DECT allows diagnostically acceptable IQ and material separation in patients with large body habitus with the major limitation of exclusion of patient anatomy and organs outside the effective dual-energy field of view.
我们的目标是评估体型较大的患者在双源双能量CT（dsDECT）扫描仪上进行门静脉期腹部计算机断层扫描（CT）时的图像质量（IQ）和物质分解情况。
这项回顾性分析纳入了连续30例体型较大（≥90kg，平均±标准差体重 = 105.4±12.35，范围 = 91 - 145kg）的患者（19例男性/11例女性，平均±标准差年龄 = 55.3±17.5岁，范围 = 27 - 87岁）的扫描数据，这些患者于2015年1月至2015年12月期间在dsDECT扫描仪上接受了门静脉期腹部双能量CT检查。对双能量CT数据集（融合图像、碘图像和虚拟平扫图像）的IQ进行了定性和定量评估。患者被分为两组（A组，≤104kg；B组，>104kg）。
A组患者的平均±标准差体重为97.2±4.5kg（范围 = 91 - 104kg），B组患者为114.8±11.7kg（范围 = 104.3 - 145.2kg）。体重>104kg患者的融合图像诊断可接受性较低（3.6对4，4/14例<3对0/16例，P = 0.03）。60%（18例患者中的28个器官）的内脏解剖结构超出了双能量视野（DEFOV），最常见的器官是肝脏和脾脏。体重>104kg患者的DEFOV外内脏器官发生率显著更高（18对10，P = 0.03）。在DEFOV外，融合图像显示出更高的图像噪声（平均值：14.48，范围 = 10.09 - 26.83对平均值：9.5，范围 = 7.3 - 15.8）（P < 0.001）和更低的信噪比（平均值：4.15，范围 = 1.5 - 7.6对平均值：7.5，范围 = 4.2 - 9.9）（P < 0.001），并且该区域无法获得物质特异性信息。在DEFOV内，碘图和虚拟平扫图像的IQ在几乎所有患者中诊断可接受性为3或更高。40cm的横向直径截断值可很好地预测有效DEFOV外的内脏解剖结构延伸情况。
双源双能量CT在体型较大的患者中可实现诊断可接受的IQ和物质分离，主要局限性是排除了有效双能量视野外的患者解剖结构和器官。
