中風是一種由疾病或是腦血流阻斷等因素引起的異質性症狀，而其缺血區域往往伴隨者水腫的現象進而改變腦組織的光學特性。各種型式的近紅外光譜學也開發出具備良好時間解析能力的系統用以量化血氧程度以及評估腦組織在缺血性中風不同時期的演化、傷害。在本研究中，我們基於高速振鏡開發了一套單對光源偵測器的二維掃描近紅外光譜系統而非增加更多頻道。透過圖像化使用者介面，可以精確的控制掃描光源的位置，同時進行量測資料擷取。連續波近紅外光譜儀模組已被運用於監控缺血性中風大鼠腦部血氧蛋白濃度的相對值變化。我們將其光源與高速振鏡定位模組結合架設出空間解析能力約為100μm，並可快速掃描大小約10x10 mm^2的區域。此二維近紅外光譜系統先以埋在光學仿體中低反射特性的條碼作測試及校正，接續以頸動脈結紮大鼠實驗來考察組織功能性變化。最後觀測壓迫人類手臂血管的變化實驗則用以演示系統能力。我們呈現了人類血管壓迫及大鼠頸動脈結紮實驗中血液動力的時空變化的量測結果。藉由此設計，我們可以利用二維近紅外光譜掃描量測以重建腦半球的血液動力和光學特性的影像。期盼此連續波近紅外光譜系統可應用於腦血管相關疾病之功能性及結構性的影像資訊。監測腦皮質血液動力時變反應的動物模型也能夠在未來提供作為中風恢復、治療手段等相關議題上作為參考。

Stroke is a heterogeneous syndrome caused by various diseases resulting from disruption of cerebral blood flow (CBF) and brain tissue necrosis. The infarct area of ischemic stroke generally accompanies with cerebral edema which could change the optical properties of the brain tissue. Various forms of near infrared spectroscopy (NIRS) have been developed to provide a good temporal resolution for quantifying blood oxygen level and for assessing damages and evolution of brain tissue during various stages of ischemic stroke. In this study, we have developed a two-dimensional NIRS scanning system based on galvo mirror scanner of one light source and one detector instead of including more channels. Continuous wave NIRS (CWNIRS) module for monitoring the relative change of hemoglobin concentrations is utilized in the ischemic stroke rat. The continuous NIRS light source was positioned precisely and was were acquired by using graphic user interface (GUI). The CWNIRS light source is mounted on 2D fast positioning module to scan an area of 100 mm^2 at a resolution of 100μm. The 2D NIRS scanning system is first observed in phantom, buried barcode with lower reflection properties for calibration purpose, and later in common carotid artery (CCA) ligation rat experiment for inspecting tissue and functional variation. Also, the scanning was applied to observe occlusion of human limb vessels. Our results show the spatiotemporal brain mapping of NIRS during hemodynamic measurements in human limb occlusion as well as in ligation of rats experiment. With this design, we can reconstruct a hemispheric brain image of the hemodynamics and the optical properties from the 2-D scanning of NIRS measurements. It is expected that CW-NIRS image system can provide functional and anatomical information of the brain with cerebral vascular disease. The cortical hemodynamic response in animal model would provide time-course monitoring for stroke recovery as well as for future design of therapeutic treatment schemes for stroke subjects in the future.

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