Halaney David L, Jonak Carrie R, Liu Junze, Davoodzadeh Nami, Cano-Velázquez Mildred S, Ehtiyatkar Pasha, Park Hyle, Binder Devin K, Aguilar Guillermo
Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States.
Laboratory of Devin Binder, Division of Biomedical Sciences, University of California, Riverside, Riverside, CA, United States.
Front Bioeng Biotechnol. 2020 Jun 30;8:659. doi: 10.3389/fbioe.2020.00659. eCollection 2020.
Repeated non-diffuse optical imaging of the brain is difficult. This is due to the fact that the cranial bone is highly scattering and thus a strong optical barrier. Repeated craniotomies increase the risk of complications and may disrupt the biological systems being imaged. We previously introduced a potential solution in the form of a transparent ceramic cranial implant called the Window to the Brain (WttB) implant. This implant is made of nanocrystalline Yttria-Stabilized Zirconia (nc-YSZ), which possesses the requisite mechanical strength to serve as a permanent optical access window in human patients. In this present study, we demonstrate repeated brain imaging of = 5 mice using both OCT and LSI across the WttB implant over 4 weeks. The main objectives are to determine if the WttB implant allows for chronic OCT imaging, and to shed further light on the question of whether optical access provided by the WttB implant remains stable over this duration in the body. The Window to the Brain implant allowed for stable repeated imaging of the mouse brain with Optical Coherence Tomography over 28 days, without loss of signal intensity. Repeated Laser Speckle Imaging was also possible over this timeframe, but signal to noise ratio and the sharpness of vessels in the images decreased with time. This can be partially explained by elevated blood flow during the first imaging session in response to trauma from the surgery, which was also detected by OCT flow imaging. These results are promising for long-term optical access through the WttB implant, making feasible chronic studies in multiple neurological models of brain disease.
对大脑进行重复的非扩散光学成像很困难。这是因为颅骨具有高度散射性，因此是一个强大的光学屏障。重复开颅会增加并发症的风险，并且可能扰乱正在成像的生物系统。我们之前曾提出一种潜在的解决方案，即一种名为“大脑之窗”（WttB）植入物的透明陶瓷颅骨植入物。这种植入物由纳米晶氧化钇稳定氧化锆（nc-YSZ）制成，它具备必要的机械强度，可作为人类患者的永久性光学接入窗口。在本研究中，我们展示了在4周内使用光学相干断层扫描（OCT）和激光散斑成像（LSI）对5只小鼠通过WttB植入物进行重复的脑部成像。主要目标是确定WttB植入物是否允许进行慢性OCT成像，并进一步阐明WttB植入物提供的光学接入在体内这段时间内是否保持稳定的问题。大脑之窗植入物能够在28天内通过光学相干断层扫描对小鼠大脑进行稳定的重复成像，且信号强度没有损失。在这个时间段内也可以进行重复的激光散斑成像，但图像中的信噪比和血管清晰度会随时间下降。这可以部分解释为在第一次成像过程中，由于手术创伤导致血流增加，这也通过OCT血流成像检测到了。这些结果对于通过WttB植入物进行长期光学接入很有前景，使得在多种脑部疾病的神经学模型中进行慢性研究成为可能。
