Dipartimento di Radiologia Cardiovascolare, Ospedale San Camillo-Forlanini, Circonvallazione Gianicolense, Rome, Italy.
Radiol Med. 2010 Dec;115(8):1258-66. doi: 10.1007/s11547-010-0583-3. Epub 2010 Sep 17.
The aim of this work was to compare the quality and noise of true non-enhanced (TNE) and virtual non-enhanced (VNE) images in patients undergoing dual-energy computed tomography (DECT) of the liver.
Twenty consecutive patients (mean age 54.7±19.9 years) prospectively underwent abdominal DECT to assess the liver using a triphasic protocol consisting of precontrast, arterial-phase and portal-phase acquisitions. Exclusion criteria were allergy to iodinated contrast material, impaired renal function and a body mass index (BMI) >35 kg/m(2). The DE portal-phase acquisition was performed with automatic dose modulation (CARE Dose 4D). Nonionic iodinated contrast material (Iomeron 400) was administered at 0.625 gI/kg with a flow rate of 3.5 ml/s. Axial VNE images were reconstructed based on the portal data set using a collimation and an increment of 5 mm and were compared with TNE images reconstructed with the same parameters. The average image quality and noise were analysed by two radiologists in separate reading sessions.
No statistically significant difference (p>0.05) in image quality was observed between VNE (4.00±0.85) and TNE images (4.35±0.58). A sufficient diagnostic quality was found in 95.0% (19/20) of VNE images and in 100% of TNE images. No statistically significant difference (p<0.05) was observed in the average image noise of VNE (9.5±0.7) and TNE (12.3±1.1) images.
Abdominal DECT allows acquisition of liver VNE images with similar image quality and lower noise than TNE. Nevertheless, a few technical limitations related to the small field of view of the second detector in patients with a high BMI and heterogeneous iodine subtraction restrict the application of this technique to selected patients only.
本研究旨在比较行双能 CT（DECT）肝脏检查的患者中真实无增强（TNE）和虚拟无增强（VNE）图像的质量和噪声。
连续 20 例患者（平均年龄 54.7±19.9 岁）行腹部 DECT 检查，采用三期对比剂增强方案，包括平扫、动脉期和门静脉期。排除标准为对碘对比剂过敏、肾功能不全和 BMI＞35 kg/m2。门静脉期采集采用自动管电流调制（CARE Dose 4D）。以 3.5 ml/s 的流率经外周静脉团注非离子型碘对比剂（Iomeron 400），用量为 0.625 gI/kg。基于门静脉期数据，采用 5mm 的准直器和层厚重建 VNE 图像，并与相同参数重建的 TNE 图像进行比较。两名放射科医生分别在两次阅读中分析图像的平均质量和噪声。
VNE（4.00±0.85）和 TNE 图像（4.35±0.58）之间的图像质量无统计学差异（p＞0.05）。VNE 图像中有 95.0%（19/20）可获得充分的诊断质量，TNE 图像中有 100%（20/20）。VNE（9.5±0.7）和 TNE（12.3±1.1）图像的平均噪声无统计学差异（p＜0.05）。
腹部 DECT 可采集具有相似图像质量和更低噪声的肝脏 VNE 图像。然而，由于第二探测器的视野较小，在 BMI 较高和碘不均匀的患者中存在一些技术限制，限制了该技术仅应用于部分患者。
