中樞神經系統之淋巴系統在多種健康狀況中扮演至關重要的角色，例如：調控體內環境平衡、免疫反應功能及廢物代謝。此系統會運輸腦脊髓液與其他分子物質到頸部深處之深頸部淋巴結。然而，現今觀測中樞神經系統之淋巴系統的技術仍有其實驗限制，例如：影像解析度不足、手術需求、動物犧牲等等。為了解決這些問題，此研究利用40 MHz高頻超音波成像技術以及兩種對比劑：微泡與奈米粒子來觀察量測此系統。
在小動物實驗中，將微泡與奈米粒子注射到側腦室，並且重點觀察與中樞神經系統之淋巴系統連結的深頸部淋巴結，此為該系統運輸物質時的首要目的地。透過組織切片與螢光反應檢測，驗證了此奈米粒子與微泡皆能進入中樞神經系統之淋巴系統並且到達深頸部淋巴結。此外，當其中一邊的深頸部淋巴結的淋巴入管被綁住時，該側淋巴結並沒有偵測到任何對比劑之訊號。
動物實驗結果顯示，高頻超音波成像技術在仿體實驗與小動物模型實驗中均能偵測到微泡與奈米粒子的訊號，並且相較於以生理實驗水注射的對照結果，這兩種對比劑在深頸部淋巴結的訊號均在30分鐘內有顯著地增加，並於20到25分鐘時達到峰值，而且兩者對中樞神經系統之淋巴系統的訊號增強效果及上升趨勢相近(微泡為0.0513±0.0114 dB/min、奈米粒子為0.0476±0.0035 dB/min)。
本研究提供了一種即時、無害與較低成本的方法來觀測中樞神經系統之淋巴系統，可進一步應用於評估量測與中樞神經系統之淋巴系統代謝相關之疾病。

Lymphatic system in the central nervous system (CNS) plays an important role in several health conditions, such as body homeostasis, immune defense and waste disposal. This system can be linked to peripheral deep cervical lymph nodes (dCLNs), which locate in the deep neck area, draining the macromolecules from the cerebrospinal fluid (CSF). However, current techniques exist some experimental limitations when operate the CNS lymphatic system observation, such as insufficient image resolution, surgical operation and animal sacrifice. Here, to overcome these problems, the 40 MHz high-frequency ultrasound (US) imaging used with two types of contrast agents, microbubbles (MBs) and nanoparticles (NPs), was applied to monitor this system. In small animal experiment, MBs and NPs were injected into the lateral ventricle, and the region of interest was focused on the dCLNs, which are the major targets of the CNS lymphatic drainage. It revealed that MBs and NPs were found in the histological and fluorescent performances of dCLNs for validations. Moreover, the lymphatic ligation resulted in no signal under US investigation. The result demonstrated that the high-frequency US imaging can detect the signals of MBs and NPs in both phantom study and small animal model experiment, and the signals of these contrast agents at dCLN areas were significantly increased within 30 minutes when compared to the saline control. The signals reached the peak intensity at 20 to 25 minutes after injection. In addition, the performances of these agents were close (0.0513±0.0114 dB/min for MBs and 0.0476±0.0035 dB/min for NPs). This novel technique provided a real-time, harmless and low cost method for the CNS lymphatic system investigation and can be further applied to diseases related to the CNS lymphatic drainage.

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