目的:证明使用新开发的基于双源能量积分探测器(EID)的多能量计算机断层扫描(MECT)系统在大型动物中同时进行双对比成像的可行性。
方法:研究了两种可能具有潜在临床应用的成像任务:头颈部(HN)CT血管造影(CTA)/CT静脉造影(CTV)碘和钆,家猪的碘和铋小肠成像。70kVAu120/Sn120kV和70kVAu140/Sn140kV的双源X射线束配置用于HN-CTA/CTV和小肠成像研究,分别。对每个研究进行测试推注扫描。颈动脉和颈静脉的感兴趣区域(ROI)用于HN-CTA/CTV成像,腹主动脉用于小肠成像,用于确定时间衰减曲线。在此基础上确定造影剂注射和CT扫描的时机。在HN-CTA/CTV研究中,在对应于碘最佳动脉增强和钆最佳静脉增强的时间点进行MECT扫描.在小肠成像研究中,在最佳时间点进行MECT扫描,同时捕获肠系膜动脉的碘增强和铋的肠增强.进行基于图像的材料分解以分解每个研究的不同材料。为了定量表征对比材料分离和错误分类,HN-CTA/CTV成像中左颈总动脉和左颈内静脉的两个ROI和肠系膜上动脉的三个ROI,回肠腔,在小肠成像中放置塌陷的回肠(回肠壁)以测量平均浓度值和标准偏差。
结果:在HN-CTA/CTV研究中,含碘的颈总动脉和含钆的颈内/颈外静脉被清晰地划分。细血管如头静脉和颈外静脉的分支是明显的,但清晰的可视化是由图像噪声在钆特异性(CTV)图像阻碍,由神经放射学家审查。在小肠成像研究中,在物质分解后的碘和铋特异性图像中,含有碘的肠系膜动脉和塌陷的肠壁和含有铋的小肠环是明显不同的。由腹部放射科医生检查。定量分析显示,CTA/CTV和小肠成像研究中,两种造影剂之间的错误分类小于1.7和0.1mg/ml,分别。
结论:用碘和钆对头颈部同时进行CTA/CTV成像和用碘和铋对小肠的动脉和肠相同时成像的可行性,使用双源EID-MECT系统,在一项猪研究中证明了这一点。与CTA/CTV中的碘和钆相比,在小肠成像中实现了碘和铋的更好的勾画和分类,这主要是由于相应的两个K边缘能量之间的分离范围更广.
OBJECTIVE: To demonstrate the feasibility of simultaneous dual-contrast imaging in a large animal using a newly developed dual-source energy-integrating detector (EID)-based multi-energy computed tomography (MECT) system.
METHODS: Two imaging tasks that may have potential clinical applications were investigated: head/neck (HN) CT angiography (CTA)/CT venography (CTV) with iodine and gadolinium, and small bowel imaging with iodine and bismuth in domestic swine. Dual-source X-ray beam configurations of 70 kV + Au120/Sn120 kV and 70 kV + Au140/Sn140 kV were used for the HN-CTA/CTV and small bowel imaging studies, respectively. A test bolus scan was performed for each
study. The regions of interest (ROIs) in the carotid artery and jugular vein for HN-CTA/CTV imaging and abdominal aorta for small bowel imaging were used to determine the time-attenuation curves, based on which the timing for contrast injection and the CT scan was determined. In the HN-CTA/CTV
study, an MECT scan was performed at the time point corresponding to the optimal arterial enhancement by iodine and the optimal venous enhancement by gadolinium. In the small bowel imaging
study, an MECT scan was performed at the optimal time point to simultaneously capture the mesenteric arterial enhancement of iodine and the enteric enhancement of bismuth. Image-based material decomposition was performed to decompose different materials for each
study. To quantitatively characterize contrast material separation and misclassification, two ROIs on left common carotid artery and left internal jugular vein in HN-CTA/CTV imaging and three ROIs on superior mesenteric artery, ileal lumen, and collapsed ileum (ileal wall) in small bowel imaging were placed to measure the mean concentration values and the standard deviations.
RESULTS: In the HN-CTA/CTV study, common carotid arteries containing iodine and internal/external jugular veins containing gadolinium were clearly delineated from each other. Fine vessels such as cephalic veins and branches of external jugular veins were noticeable but clear visualization was hindered by image noise in gadolinium-specific (CTV) images, as reviewed by a neuroradiologist. In the small bowel imaging
study, the mesenteric arteries and collapsed bowel wall containing iodine and the small bowel loops containing bismuth were clearly distinctive from each other in the iodine- and bismuth-specific images after material decomposition, as reviewed by an abdominal radiologist. Quantitative analyses showed that the misclassifications between the two contrast materials were less than 1.7 and 0.1 mg/ml for CTA/CTV and small bowel imaging studies, respectively.
CONCLUSIONS: Feasibility of simultaneous CTA/CTV imaging in head and neck with iodine and gadolinium and simultaneous imaging of arterial and enteric phases of small bowel with iodine and bismuth, using a dual-source EID-MECT system, was demonstrated in a swine study. Compared to iodine and gadolinium in CTA/CTV, better delineation and classification of iodine and bismuth in small bowel imaging were achieved mainly due to wider separation between the corresponding two K-edge energies.