Kawahara Daisuke, Ozawa Shuichi, Yokomachi Kazushi, Higaki Toru, Fujioka Chikako, Mori Masayoshi, Nagata Yasushi
Radiation Therapy Section, Division of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima City, 734-8551, Japan.
Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima City, 734-8551, Japan.
Australas Phys Eng Sci Med. 2019 Sep;42(3):819-826. doi: 10.1007/s13246-019-00762-5. Epub 2019 May 20.
In a previous study, a phantom study of a contrast agent extraction system with computed tomography (CT) number and raw-data-based electron density (ED) was described. The current study improved this system with monochromatic CT (mCT) number and evaluated an anthropomorphic phantom for delineation of the contrast-enhanced region. Dual-energy CT images were scanned with a tissue-equivalent phantom and an anthropomorphic phantom with an iodinated contrast agent (1-130 mg/mL). The 40, 70, and 130 keV mCT images were reconstructed with 80 and 135 kV CT images. The contrast agent was separated from other materials using the gradient of the mCT number (GmCT) and the threshold mCT numbers. The system was analyzed using in-house software with Python. The evaluation of the accuracy for the contrast agent extraction was performed by measuring the ratio of the volume (ROV). The mCT number of the contrast agent and bone materials, liver, and muscle in the tissue-equivalent phantom was obviously greater than - 78 HU. The deviation of the mCT numbers between bone materials in tissue-equivalent phantom and the contrast agent were larger than 8 HU. The GmCT was within 4.0 in the tissue-equivalent phantom and more than 6.0 in the contrast agent. The ROV was 0.97-1.00 at more than 1 mg/mL contrast agent. Improved the contrast agent extraction system could be used for a patient's CT image. It could extract the iodinated tumor or lesion automatically. The contrast agent extraction system was improved by the mCT number. It is expected to only extract the contrast-enhanced region automatically.
在之前的一项研究中，描述了一项关于基于计算机断层扫描（CT）值和原始数据的电子密度（ED）的造影剂提取系统的体模研究。当前的研究用单色CT（mCT）值改进了该系统，并评估了用于描绘造影剂增强区域的仿真人体体模。使用组织等效体模和含有碘化造影剂（1 - 130 mg/mL）的仿真人体体模扫描双能CT图像。用80 kV和135 kV的CT图像重建40、70和130 keV的mCT图像。利用mCT值梯度（GmCT）和阈值mCT值将造影剂与其他物质分离。使用带有Python的内部软件对该系统进行分析。通过测量体积比（ROV）来评估造影剂提取的准确性。组织等效体模中造影剂以及骨材料、肝脏和肌肉的mCT值明显大于 - 78 HU。组织等效体模中骨材料与造影剂之间的mCT值偏差大于8 HU。在组织等效体模中GmCT在4.0以内，在造影剂中大于6.0。当造影剂浓度超过1 mg/mL时，ROV为0.97 - 1.00。改进后的造影剂提取系统可用于患者的CT图像。它可以自动提取碘化肿瘤或病变。造影剂提取系统通过mCT值得到了改进。有望仅自动提取造影剂增强区域。
