实时三维多普勒傅里叶频域光学相干层析成像系统 Real-time 3D Doppler SD-OCT

辅助超显微外科血管吻合及评价血管吻合质量的研究

研究目的：

穿支皮瓣是近年来整形外科领域的研究热点，由于在改善皮瓣受区外形和功能的同时，最大程度地减少了皮瓣供区外观和功能的损害，因此已被广泛应用于头颈、躯干与四肢创面的整形与修复。随着穿支皮瓣意识的不断深化，以及其他精细显微操作诸如指尖游离移植及部分耳-皮肤复合组织移植修复上睑及气管缺损等手术的需要，超显微外科操作技术（即直径为0.3-0.8mm 的微小血管或单一神经束进行剥离和吻合的显微外科操作技术）应运而生。由于穿支血管管腔细小、管壁菲薄，因此穿支皮瓣游离移植手术对显微外科（/超显微外科）操作技术的要求比较高。如何能够在无创情况下对显微血管吻合进行有效的指导和监测是显微外科领域和生物医学工程领域探讨的热点问题。OCT 技术是一种新型的医学层析成像方法，能够对生物体进行无伤害的活体检测，获得生物组织内部微观结构的高分辨截面图像。本研究首次将先进的实时、三维多普勒傅里叶频域光学相干层析成像技术（Real-time 3D Doppler SD-OCT）应用于鼠股动脉血管吻合模型及血栓模型，以研究OCT技术对于超显微血管立体结构及血管内血栓的成像能力，探讨OCT技术对超显微血管吻合操作的指导、监测及血管吻合质量的评价作用。

研究方法：

1．活体小鼠股动脉应用光学相干断层成像技术探测小血管超微立体结构模型

的建立及活体大鼠股动脉应用光学相干断层成相技术监测小血管血管吻合操作：对活体状况下的小鼠股动脉，应用3D-SD OCT 探测仪，以非接触方式分别对血管进行冠状面、矢状面及横截面扫描。将通过OCT 扫描获得的数据导入Matlab 软件，获取图像数据。对图像进行三维重建，从而获得小血管的超微三维立体结构图像。在大鼠股动脉血管吻合同时，应用3D-SD OCT 同步、实时地进行监测，以探讨OCT技术对超显微血管吻合操作的监测和指导作用。

2．活体小鼠股动脉应用光学相干断层成像技术探测三氯化铁诱导后小血管血栓形成的实验研究：应用三氯化铁在小鼠股动脉建立血栓模型。对活体状况下的小鼠股动脉，应用3D-SD OCT 探测仪，以非接触方式分别对血管进行冠状面、矢状面及横截面扫描。观察时间按照血栓建模后1min、1h、应用肝素后4h、18h及24h 的时间间隔进行观察。将通过3D-SD OCT 扫描获得的数据导入Matlab 软件，获取图像数据。

3．活体小鼠股动脉应用光学相干断层成像技术探测血管吻合后小血管血栓形成的实验研究：将实验动物随机分为两组，分别为血管正常吻合组及血管异常吻合组。分别于吻合前及吻合后1h对血管进行冠状面、矢状面及横截面扫描。将通过3D-SDOCT 扫描获得的数据导入Matlab 软件，获取图像数据。被检测节段血管取材后经H-E染色，置显微镜下观察血栓形成及血管壁情况。

结果：

1. 通过OCT 图像采集以及后期处理，可以清晰地看到小鼠股动脉在冠状面、矢状面及横截面上的超微结构以及血管的三维立体图像。可以看到光滑的血管内壁及通畅的血流。通过重建三维图像，可以监测到血管的三维立体结构图，甚至血管内膜和管腔。在大鼠股动脉血管吻合的过程中，通过OCT 的扫描，可以实时、无创地监测吻合缝线穿出点的位置，对于缝及对侧血管壁的操作失误可以做出明确的诊断。

2. 结合OCT 图像及超声多普勒血流图像，可以明确诊断出小鼠股动脉内血栓，并跟踪血栓形成的动态过程。

3. 结合OCT 图像及超声多普勒血流图像，可以诊断出小鼠股动脉吻合后血栓形

成，并且与病理结果相符合。

结论：

1. 实时三维多普勒傅里叶频域光学相干层析成像技术（Real-time 3D DopplerSD-OCT）具有实时、客观、定量、无侵害、非接触、可重复、高灵敏度、高分辨率等优点。

2. 通过实时三维多普勒傅里叶频域光学相干层析成像技术（Real-time 3D Doppler SD-OCT），可以实时、无创地获得微小血管的超微结构图像以及三维立体图像。

3. 在微血管吻合过程.92 TD (<)中，通过实时三维多普勒傅里叶频域光学相干层析成像技术（Real-time 3D Doppler SD-OCT），可以实时、无创地监测血管吻合的全过程，对血管吻合过程具有指导和监测的作用。

4. 通过实时三维多普勒傅里叶频域光学相干层析成像技术（Real-time 3D Doppler SD-OCT），可以监测微小血管内血栓形成以及血管吻合后血栓形成的病理过程。

Applications of Real-time 3D Doppler Spectral DomainOptical Coherence Tomography System(Real-time 3D Doppler SD-OCT) in Guiding and Evaluating SuperMicrosurgery

ABSTRACT

Purpose：

Perforator flaps have proven to be one of the most invaluable options in reconstructive surgery. It plays a crucial role in the soft-tissue defect reconstruction with functional and aesthetic outcomes in the recipient site and minimal morbidities in the donor site. However, the small-sized caliber and thinness of these perforating vessels impose great challenge to the surgeons. In such cases, it is most desirable to have a non-invasive measurement that could effectively guide microsurgical anastomosis and then evaluate the quality of the anastomosis through a visualized system. In this study, we utilized the 3D Spectral Domain Optical Coherence Tomography (3D SD-OCT) to evaluate the quality of the microsurgical anastomosis and thrombosis induced in the murine’s femoral artery. The feasibility and accuracy of this novel method are also investigated.

Method:

1. To establish an animal model for exploring the ultrastructure of small vessels of mice in vivo using 3D SD-OCT. OCT was used to scan the femoral arteries of mice and the coronal-, sagittal-, and cross-sections of these vessels were obtained in a non-contact manner before microvascular anastomosis. The scanned images were then imported into a computer and converted into visualized image data. The three-dimensional ultrastructural images of the small vessels were obtained through 3D reconstruction of the image data. During the process of microvascular anastomosis, OCT was used to monitor the procedure on a synchronous and real-time basis. The role of the OCT in monitoring and guiding the microvascular anastomosis is then investigated.

2. To evaluate the accuracy of using the OCT to detect a thrombosis in vivo. The thrombosis animal model was established by intravascular administration of the ferric chloride into the femoral arteries of the mice. At 1 minute and 1 hour after administration, OCT was used to scan the femoral arteries of mice. Then heparin was applied to dissolve the thrombosis followed by OCT scanning at 4-hour, 18-hour and 24-hour. The coronal-, sagittal-, and cross-sections of these vessels were obtained in a non-contact manner. The scanned images were imported into the Matlab software to obtain the image data.

3. Investigation of the efficacy of OCT in monitoring thrombosis induced by incorrect surgical performance. Subjects are randomly divided into 2 groups ： normal anastomosis and poor anastomosis. The OCT scanning was performed 1 hour before and after anastomosis. The scanned vessel section was evaluated by H&E staining to confirm the results of OCT scanning.

Results:

1. The reconstructed images of the 3D SD-OCT presented clearly the ultrastructure of the femoral artery in the cross, coronal and sagittal planes and the three dimensional view of the vessel. During the anastomosis, the OCT scanning can provide real-time information of the locations where the suture went through. By such way, the incorrect performance of suturing to the opposite wall can be accurately diagnosed.

2. The thrombosis can be accurately detected by the 3D SD-OCT scanning. The pathophysiological cascade of thrombogenesis and the effect of an anticoagulation treatment can also be showed by the 3D SD-OCT scanning.

3.3D SD-OCT accurately captured the potential risks of thrombegenesis by surgical

errors, and the results were confirmed by the histopathological analysis.

Conclusion：

1.3D SD-OCT can provide real-time information. It is a non-invasive, objective, quantifiable, precise, contact-free and replicable measure to monitor the vessel with high resolution.

2. 3D SD-OCT can present three-dimensional ultrastructural images of small essels.

3. 3D SD-OCT can visualize the blood vessel during the process of anastomosis and guide the anastomosis procedure.

4. 3D SD-OCT can detect arterial thrombosis and show the pathophysiological cascade of thrombogenesis.