近紅外光擴散光學腦造影技術研發

Development of Near-infrared Diffuse Optical Brain Imaging Technique

莊競程(Ching-Cheng Chuang)

指導教授 ： 陳中明

共同指導教授 ： 孫家偉

國立臺灣大學/工學院/醫學工程學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.00037

摘要

近紅外擴散光學造影是一項非侵入式技術，廣泛地做為量測組織生理的研究工具，特別是在大腦造影方面。各種光學造影技術已經被開發，但仍然幾項問題存在，包含訊號雜訊比的評估、複雜的影像重建演算法之簡化、光源與檢測器間距之最佳化選擇、大腦結構對光子遷徙的影響、以及大腦體積造影，都仍待充分地瞭解。在本論文中，我們首先透過蒙地卡羅的模擬來研究大腦結構影像對於近紅外擴散光學造影技術的影響。另外，在大腦功能性造影方面，我們展示了功能性近紅外造影技術在精神分裂症鑑別分析之臨床應用。
在大腦結構性造影方面，我們以體內MRI T1影像透過影像處理技術重建的三維大腦模型，來探討近紅外光量測的個體化校正，並藉由蒙地卡羅進行模擬分析。透過蒙地卡羅模擬，光子在基於三維MRI影像所重建的大腦模型中之傳播已經被報告；然而，並沒有以病人導向的模擬來進行近紅外光學量測的個體化校正。我們的結果顯示，透過三維MRI時間解析的大腦結構重建模擬方法以接近真實的人腦情況，來對於近紅外光學系統設計和具有先驗MRI數據的個體化校正提供有用的訊息。探討以近紅外光量測腦部結構對於空間敏感度分布之個體差異，成年與老年志願者兩種大腦模型被建立，並藉由不同光源與檢測器的間距來進行蒙地卡羅模擬。結果指出，近紅外光造影技術在大腦萎縮而產生的結構性訊號的檢測上，是一項可行且靈敏的方法。進一步地，我們提出一項嶄新的近紅外光大腦體積造影方法，用以量測大腦體積結構的變化。使用大腦體積變化的不同特徵來建構正常人、老年人、和典型的阿茲海默症患者的模型，並透過蒙地卡羅模擬來研究光子在此三種不同大腦結構中的相關特性。我們的研究顯示近紅外光大腦體積造影技術能夠在神經退化性疾病之臨床應用上指出大腦萎縮程度，並且以病人導向的方式進行量測。
　　對於精神分裂症的鑑別分析，我們也展示功能性近紅外光造影技術之臨床應用。透過語言流暢度測試，我們對於大腦前額葉皮質的功能性光學斷層掃描造影進行統計分析，在精神分裂症與正常對照之間的影像結果是顯著差異的，特別是在左前額葉皮質。根據我們的結果，近紅外擴散光學造影技術基於其本身的優點，可以成為在病患導向診斷上的有用臨床與研究工具。

關鍵字

大腦體積造影 ； 擴散光學造影 ； 蒙地卡羅模擬 ； 精神分裂症判別分析

並列摘要

Near-infrared diffuse optical imaging is a non-invasive technique comprehensive as a research tool to measure tissue physiology, particularly in brain imaging. Various optical imaging techniques have been developed, but several issues remain. These, including signal-to-noise ratio evaluation, simplifying the complex algorithms of image reconstruction, the optimal choice of source-detector separation, the brain structural effects on light propagation, and the brain volume imaging, remain to be fully understood. In this thesis, we first investigate the near-infrared diffuse optical imaging technique for brain structural imaging with Monte Carlo simulation. Besides, for brain functional imaging, we demonstrate functional near-infrared spectroscopy (fNIRS) measurements on the clinical application for discriminant analysis of schizophrenia diagnosis.
For brain structural imaging, we offer an approach for brain modeling based on the image segmentation process with in vivo magnetic resonance imaging (MRI) T1 three-dimensional image to investigate the individualized calibration for NIRS measurement with Monte Carlo simulation. Monte Carlo simulations of light propagation in full-segmented three-dimensional MRI-based anatomical models of the human head have been reported. However, there is no patient-oriented simulation for individualized calibration with NIRS measurement. Our results indicate that the three-dimensional time-resolved brain modeling method approaches the realistic human brain providing helpful information for NIRS systematic design and calibration for an individualized case with prior MRI data. To investigate individual differences in brain structure with spatial sensitivity profiles by NIRS measurement, two brain models from an adult and an aged volunteer were modeled to implement Monte Carlo simulation with various source-detector separations. The results indicate that NIRS measurement is a feasible and sensitive approach to structural signals generated in “brain atrophy.”
Further, we propose a novel approach that uses near-infrared brain volumetric imaging to detect volumetric brain changes. The healthy, aged, and typical Alzheimer’s disease brains were modeled using the different characterization of volumetric brain changes to investigate the related features among these three brains with Monte Carlo simulation. Our study shows that near-infrared brain volumetric imaging can indicate brain atrophy for the clinical application of neurodegenerative diseases with patient-oriented measurement.
We also demonstrate the clinical application of functional NIRS for discriminant analysis of schizophrenia. We performed statistical analyses of the prefrontal cortex (PFC) functional optical topography (fOT) image with a verbal fluency test. The imaging results between schizophrenia and healthy controls were significantly different, especially in the left PFC. According to our results, near-infrared diffuse optical imaging, with its advantages, could be a helpful clinical and research tool for patient-oriented diagnosis.

並列關鍵字

Near-infrared diffuse optical imaging ； volumetric brain imaging ； Monte Carlo simulation ； schizophrenic discriminant analysis

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