基於統計模型分析之腦動脈循環中的血流

Abstract

腦血管系統是一個複雜的血管網絡，為大腦提供氧氣和營養，同時還調節著大腦內 的血流和壓力。維持大腦的血流和壓力對於正常的大腦功能至關重要，因為任何干 擾都可能導致神經系統疾病甚至死亡。因此，為了開發有效的治療方法，了解腦血 管的定量特徵是必不可少的。 本研究提出了一種創新方法來定量分析腦血管系統，利用了先進的成像技術和計 算模型。這些方法包含了對 Time-of-flight (TOF) MRA 影像中觀察到的血管進行獨 特的數學表示。接著對影像進行處理，以量化血管網絡的特性。 我們從兩個數據庫中收集了血管數據，它們分別包含 61 名健康受試者和 45 名健 康受試者的數據。第一組數據集包含了人腦數位重建並以 SWC 格式呈現，而第二 個數據集則包括了腦血管 TOF-MRA 體積及其對應的基準真相。對於第二組中所 有選定的受試者，其腦血管使用了一套半自動化軟體來進行血管追蹤。為了計算腦 血流，我們採用了 Flores 所提出的模型，此模型成功解決了每個節點的壓力以及 腦血流 (CBF)。 我們的統計分析結果顯示，無論是男性還是女性，其大腦血流在穩態時，呈現逐漸 下降，同時還觀察到男性的大腦血流傾向於高於女性。統計分析結果還發現，所有 受試者在心臟頻率下僅出現微小的相位偏移角。另一方面，微小的相位偏移意味著 壓力和血流幾乎同時發生變化，表示著循環系統的不同組成部分之間的緊密聯繫。 這可能意味著擁有良好的心血管健康及有效的血流調節。

The cerebral vasculature is a complex network of blood vessels that provides oxygen and nutrients to the brain, while also regulating blood flow and pressure within the brain. The maintenance of the cerebral blood flow and pressure is critical for the normal functioning of the brain, as any disruptions can lead to neurological disorders and even death. Therefore, to understand the quantitative aspects of cerebrovascular is essential to develop effective treatments for these conditions. The study presents an innovative method for quantitatively analyzing of cerebral vasculature using advanced imaging techniques and computational modelling. This approach includes a unique mathematical representation of blood vessels observed in Time-of-flight (TOF) MRA images. The images were then processed to quantify the properties of the vascular network. We collect the vessel data from two database which they contain 61 healthy subjects and 45 healthy subjects respectively. The initial dataset comprises digital reconstructions of the human brain presented in SWC format, whereas the second dataset includes cerebrovascular TOF-MRA volumes along with their corresponding ground truth. For all selected subjects from the second group, brain vessels were traced using a semi-automated software. To calculate the blood flow, we adapt the model proposed by Flores. This solves the pressure at each node as well as cerebral blood flow (CBF). Our statistical analysis results showed a gradual decline in the steady state level of cerebral blood flow for both males and females, it was also observed that males tend to exhibit higher cerebral blood flow compared to females. This also showed that all subjects displayed only a minor phase shift angle at the cardiac frequency. On the other hand, the negligible phase shift implies that pressure and flow undergo nearly simultaneously changes, pointing towards a close interconnection between the different components of the circulatory system. This could signify optimal cardiovascular well-being and effective regulation of blood flow.