三維高分辨率生物組織流場檢測與成像技術
發(fā)布時間：2018-07-31 18:14
【摘要】：光學相干層析成像(Optical Coherence tomography,OCT)技術是一種非侵入、高分辨率的成像技術,能獲取生物組織斷層信息的醫(yī)學成像技術。其中以掃頻激光器為光源的掃頻光學相干層析成像技術(Swept source OCT,SS-OCT)具有成像速度快、信噪比和靈敏度高的特點,是目前研究和生物醫(yī)學成像的主要OCT形式。OCT和包括多普勒技術等在內(nèi)的流場技術相結合可以獲取樣品內(nèi)部流速信息,擴展了OCT的成像功能。對于生物組織,很多疾病與血流流速狀況和血管形態(tài)相關。皮膚的病變,畸形和燒傷等都會引起皮膚表層毛細血管形態(tài)上的變化和病變。在眼科學方面,人類視網(wǎng)膜的血管分布卻較為稀疏,但是視網(wǎng)膜是人體中單位重量耗氧量最高的組織。這一矛盾體被公認為是視網(wǎng)膜容易產(chǎn)生各種血管類疾病的原因。因此,對血液循環(huán)系統(tǒng)提供高分辨率的三維成像將成為這類疾病預防、診斷和治療的關鍵。本文對掃頻光學相干層析成像系統(tǒng)中影響流場檢測的若干問題進行了研究,并致力于流場圖像質量的提高,主要內(nèi)容包括:搭建了中心波長1310 nm的掃頻光學相干層析成像系統(tǒng),對兩個多面轉鏡掃頻激光器不穩(wěn)定性問題進行了測量與分析。其中輸出功率波動和光譜錯位會導致干涉信號強度和相位的不穩(wěn)定,進而影響到OCT結構與流場成像效果。掃頻范圍的波動則會降低信號利用率,從而降低圖像分辨率和信噪比。針對以上問題提出了一種基于馬赫曾德干涉儀的相位、強度矯正方法,該方法可以在不截取信號的情況下對相位進行矯正,消除了干擾豎條紋,提高了流場檢測效果以及圖像的分辨率和信噪比。在處理過程中,干涉信號在時域就完成了對齊,因此獲取一次馬赫曾德干涉信號的相位信息,即可完成所有干涉信號的重采樣過程,提高了成像速度。對流體網(wǎng)絡模型進行了三維成像,驗證了矯正方法的有效性;同時對兔耳部血管、人手指皮膚血管進行了在體流場檢測,獲得了良好的圖像效果;其間還利用GPU對相位矯正算法進行了加速,能夠對樣品進行實時多普勒流速成像。
[Abstract]:Optical coherence tomography (Optical Coherence tomographic Oct) is a non-invasive, high-resolution imaging technique, which can obtain the information of biological tissue fault. The scanning optical coherence tomography (Swept source OCTS- Oct), which uses the scanning laser as the light source, has the advantages of fast imaging speed, high signal-to-noise ratio and high sensitivity. It is the main OCT form of biomedical imaging. Oct and flow field technology, including Doppler technology, can obtain the flow velocity information of the sample, and expand the imaging function of OCT. For biological tissue, many diseases are associated with blood flow velocity and vascular morphology. Skin lesions, deformities and burns can cause morphological changes in the surface capillaries. In ophthalmology, the blood vessels of human retina are sparsely distributed, but the retina is the tissue with the highest oxygen consumption per unit weight. This contradiction is recognized as the cause of various vascular diseases in the retina. Therefore, high resolution 3D imaging of the circulatory system will be the key to the prevention, diagnosis and treatment of these diseases. In this paper, some problems affecting the detection of flow field in the optical coherence tomography system are studied, and the quality of the flow field image is improved. The main contents are as follows: the scanning optical coherent tomography system with the center wavelength of 1310 nm is built. The instability of two multi-mirror scanning lasers is measured and analyzed. The fluctuation of output power and the misalignment of spectrum will lead to the instability of the intensity and phase of the interference signal, which will affect the OCT structure and the imaging effect of the flow field. The fluctuation of sweep range will reduce the signal utilization ratio and thus reduce the image resolution and signal-to-noise ratio (SNR). In order to solve the above problems, a phase and intensity correction method based on Mach Zende interferometer is proposed. This method can correct the phase without intercepting the signal and eliminate the interference of vertical stripes. The detection effect of the flow field and the resolution and signal-to-noise ratio of the image are improved. In the process of processing, the interference signal is aligned in the time domain, so if the phase information of the Mach Zende interference signal is obtained once, the resampling process of all the interference signals can be completed and the imaging speed can be improved. Three-dimensional imaging of the fluid network model was performed to verify the effectiveness of the correction method, and in vivo flow field detection of rabbit ear vessels and human finger skin vessels was carried out, and a good image effect was obtained. Meanwhile, the phase correction algorithm is accelerated by GPU, and the real time Doppler velocity imaging of the sample can be carried out.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：R445
本文編號：2156422
[Abstract]:Optical coherence tomography (Optical Coherence tomographic Oct) is a non-invasive, high-resolution imaging technique, which can obtain the information of biological tissue fault. The scanning optical coherence tomography (Swept source OCTS- Oct), which uses the scanning laser as the light source, has the advantages of fast imaging speed, high signal-to-noise ratio and high sensitivity. It is the main OCT form of biomedical imaging. Oct and flow field technology, including Doppler technology, can obtain the flow velocity information of the sample, and expand the imaging function of OCT. For biological tissue, many diseases are associated with blood flow velocity and vascular morphology. Skin lesions, deformities and burns can cause morphological changes in the surface capillaries. In ophthalmology, the blood vessels of human retina are sparsely distributed, but the retina is the tissue with the highest oxygen consumption per unit weight. This contradiction is recognized as the cause of various vascular diseases in the retina. Therefore, high resolution 3D imaging of the circulatory system will be the key to the prevention, diagnosis and treatment of these diseases. In this paper, some problems affecting the detection of flow field in the optical coherence tomography system are studied, and the quality of the flow field image is improved. The main contents are as follows: the scanning optical coherent tomography system with the center wavelength of 1310 nm is built. The instability of two multi-mirror scanning lasers is measured and analyzed. The fluctuation of output power and the misalignment of spectrum will lead to the instability of the intensity and phase of the interference signal, which will affect the OCT structure and the imaging effect of the flow field. The fluctuation of sweep range will reduce the signal utilization ratio and thus reduce the image resolution and signal-to-noise ratio (SNR). In order to solve the above problems, a phase and intensity correction method based on Mach Zende interferometer is proposed. This method can correct the phase without intercepting the signal and eliminate the interference of vertical stripes. The detection effect of the flow field and the resolution and signal-to-noise ratio of the image are improved. In the process of processing, the interference signal is aligned in the time domain, so if the phase information of the Mach Zende interference signal is obtained once, the resampling process of all the interference signals can be completed and the imaging speed can be improved. Three-dimensional imaging of the fluid network model was performed to verify the effectiveness of the correction method, and in vivo flow field detection of rabbit ear vessels and human finger skin vessels was carried out, and a good image effect was obtained. Meanwhile, the phase correction algorithm is accelerated by GPU, and the real time Doppler velocity imaging of the sample can be carried out.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：R445
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