时间分辨、动态计算机断层扫描血管造影术，用于主动脉内漏的表征和 通过 2D-3D 融合成像进行治疗指导
Summary
动态计算机断层扫描血管造影 （CTA） 成像为表征主动脉内节提供了额外的诊断价值。该协议描述了一种定性和定量方法，使用时间衰减曲线分析来表征内漏。图示了使用2D-3D图像融合将动态CTA成像与荧光透视相结合的技术，以便在治疗过程中提供更好的图像指导。
Abstract
在美国，超过 80% 的腹主动脉瘤通过血管内主动脉瘤修复术 （EVAR） 进行治疗。血管内入路需要良好的早期结果，但 EVAR 后进行充分的随访影像学检查对于维持长期阳性结局至关重要。潜在的移植物相关并发症包括移植物迁移、感染、分数和内漏，最后一个是最常见的。EVAR后最常用的成像是计算机断层扫描血管造影（CTA）和双功超声。动态、时间分辨计算机断层扫描血管造影 （d-CTA） 是一种表征内漏的合理新技术。在采集过程中，在内移植物周围依次进行多次扫描，从而可以很好地可视化造影剂通道和移植物相关并发症。d-CTA的这种高诊断准确性 可以通过图像融合 实施到治疗中，并减少额外的辐射和造影剂暴露。
该协议描述了该模式的技术方面：患者选择，初步图像审查，d-CTA扫描采集，图像处理，定性和定量油内节表征。还演示了使用2D-3D融合成像将动态CTA整合到术中透视中以促进靶向栓塞的步骤。总之，时间分辨的动态CTA是具有额外定量分析的内油脂表征的理想方式。它可以通过指导干预措施来减少内油治疗期间的辐射和碘化造影剂暴露。
Introduction
血管内主动脉瘤修复术 （EVAR） 的早期死亡率结果优于开放性主动脉修复术1。该方法的侵入性较小，但由于内漏、移植物迁移、骨折，可能导致更高的中长期再干预率2。因此，更好的EVAR监测对于实现良好的中长期结果至关重要。
目前的指南建议常规使用双功超声和三相CTA3。动态、时间分辨计算机断层扫描血管造影 （d-CTA） 是一种用于 EVAR 监测的相对较新的模式4。在d-CTA期间，在造影剂注射后沿着时间衰减曲线的不同时间点进行多次扫描，因此称为时间分辨成像。与传统的CTA5相比，这种方法在表征EVAR后的内漏方面显示出更好的准确性。时间分辨采集的一个优点是能够定量分析所选感兴趣区域 （ROI） 中的 Hounsfield 单位变化 6。
使用d-CTA准确表征内漏的另一个好处是，扫描可用于干预期间的图像融合，从而可能最大限度地减少对进一步诊断性血管造影的需求。图像融合是一种将先前采集的图像叠加到实时荧光透视图像上的方法，以指导血管内手术并随后减少造影剂消耗和辐射暴露7，8。使用3D动态CTA扫描的混合手术室（OR）中的图像融合可以通过两种方法实现：（1）3D-3D图像融合：其中3D d-CTA与术中获取的非对比度锥形束CT图像融合，（2）2D-3D图像融合，其中3D d-CTA与双平面（前后和侧）透视图像融合。2D-3D图像融合方法已被证明与3D-3D技术相比，可显着降低辐射9。
该协议描述了用于内漏表征的动态CTA成像的技术和实践方面，并引入了2D-3D图像融合方法和d-CTA用于术中图像指导。
Protocol
Representative Results
Discussion
动态、时间分辨的CTA是主动脉成像武器库中的一种附加工具。该技术可以在EVAR后准确诊断内漏，包括识别流入/目标血管4。
具有双向工作台移动功能的第三代 CT 扫描仪可提供动态采集模式，沿时间衰减曲线提供更好的时间采样6。为了在方案中实现最高精度，个性化图像采集至关重要：根据患者要求（高BMI – 更高的kV，用扫描覆盖整个内移?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
作者希望感谢Danielle Jones（西门子医疗临床教育专家）和休斯顿卫理公会DeBakey心脏和血管中心的整个CT技术专家团队，以支持成像方案。
Materials
| Siemens Artis Pheno | Siemens Healthcare | https://www.siemens-healthineers.com/en-us/angio/artis-interventional-angiography-systems/artis-pheno | Other commercially available C-arm systems can provide image fusion too |
| SOMATOM Force CT-scanner | Siemens Healthcare | https://www.siemens-healthineers.com/computed-tomography/dual-source-ct/somatom-force | Any commercially available third generation CT-scanner can perform such dynamic imaging |
| Syngo.via | Siemens Healthcare | https://www.siemens-healthineers.com/en-us/medical-imaging-it/advanced-visualization-solutions/syngovia | Any DICOM file viewer with 4D processing capabilities can review the acquired time-resolved images, TAC are software dependent. |
| Visipaque (Iodixanol) | GE Healthcare | #00407222317 | Contrast material |
References
- Lederle, F. A., et al. Open versus endovascular repair of abdominal aortic aneurysm. New England Journal of Medicine. 380 (22), 2126-2135 (2019).
- De Bruin, J. L., et al. Long-term outcome of open or endovascular repair of abdominal aortic aneurysm. New England Journal of Medicine. 362 (20), 1881-1889 (2010).
- Chaikof, E. L., et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. Journal of Vascular Surgery. 67 (1), 2-77 (2018).
- Sommer, W. H., et al. Time-resolved CT angiography for the detection and classification of endoleaks. Radiology. 263 (3), 917-926 (2012).
- Hou, K., et al. Dynamic volumetric computed tomography angiography is a preferred method for unclassified endoleaks by conventional computed tomography angiography after endovascular aortic repair. Journal of American Heart Association. 8 (8), 012011 (2019).
- Berczeli, M., Lumsden, A. B., Chang, S. M., Bavare, C. S., Chinnadurai, P. Dynamic, time-resolved computed tomography angiography technique to characterize aortic endoleak type, inflow and provide guidance for targeted treatmen. Journal of Endovascular Therapy. , (2021).
- Hertault, A., et al. Impact of hybrid rooms with image fusion on radiation exposure during endovascular aortic repair. European Journal of Vascular and Endovascular Surgery. 48 (4), 382-390 (2014).
- Maurel, B., et al. Techniques to reduce radiation and contrast volume during EVAR. Journal of Cardiovascular Surgery (Torino). 55 (2), 123-131 (2014).
- Schulz, C. J., Bockler, D., Krisam, J., Geisbusch, P. Two-dimensional-three-dimensional registration for fusion imaging is noninferior to three-dimensional- three-dimensional registration in infrarenal endovascular aneurysm repair. Journal of Vascular Surgery. 70 (6), 2005-2013 (2019).
- Madigan, M. C., Singh, M. J., Chaer, R. A., Al-Khoury, G. E., Makaroun, M. S. Occult type I or III endoleaks are a common cause of failure of type II endoleak treatment after endovascular aortic repair. Journal of Vascular Surgery. 69 (2), 432-439 (2019).
- Koike, Y., et al. Dynamic volumetric CT angiography for the detection and classification of endoleaks: application of cine imaging using a 320-row CT scanner with 16-cm detectors. Journal of Vascular and Interventional Radiology. 25 (8), 1172-1180 (2014).
- Macari, M., et al. Abdominal aortic aneurysm: Can the arterial phase at CT evaluation after endovascular repair be eliminated to reduce radiation dose. Radiology. 241 (3), 908-914 (2006).
- Brambilla, M., et al. Cumulative radiation dose and radiation risk from medical imaging in patients subjected to endovascular aortic aneurysm repair. La Radiologica Medica. 120 (6), 563-570 (2015).
- Buffa, V., et al. Dual-source dual-energy CT: dose reduction after endovascular abdominal aortic aneurysm repair. La Radiologica Medica. 119 (12), 934-941 (2014).
- Apfaltrer, G., et al. Quantitative analysis of dynamic computed tomography angiography for the detection of endoleaks after abdominal aorta aneurysm endovascular repair: A feasibility study. PLoS One. 16 (1), 0245134 (2021).
- Kinner, S., et al. Dynamic MR angiography in acute aortic dissection. Journal of Magnetic Resonance Imaging. 42 (2), 505-514 (2015).
- Buls, N., et al. Improving the diagnosis of peripheral arterial disease in below-the-knee arteries by adding time-resolved CT scan series to conventional run-off CT angiography. First experience with a 256-slice CT scanner. European Journal of Radiology. 110, 136-141 (2019).
- Grossberg, J. A., Howard, B. M., Saindane, A. M. The use of contrast-enhanced, time-resolved magnetic resonance angiography in cerebrovascular pathology. Neurosurgical Focus. 47 (6), 3 (2019).
