Artikel
Analysis of bloodvessel micro-structure and blood flow by optical coherence tomography
Analyse von Blutfluss und Mikrostruktur von Blutgefäßen durch optische Kohärenz-Tomographie
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Veröffentlicht: | 11. April 2007 |
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Gliederung
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Objective: Optical Coherence Tomography (OCT) is a laser based technology for in vivo imaging which allows a high-resolution view into intact tissues. We have previously demonstrated the capacity and high sensitivity of OCT in the detection of experimental gliomas in mouse brain as well as human brain tumor tissue in situ. The basis for this analysis is the intensity of the reflection of laser light from deep tissue layers. By using a new software, developed for this purpose, further information can be extracted from the OCT signal. Doppler-OCT uses the phase difference of the reflection between the corpuscular blood component in motion compared to a reference beam, which allows visualization of the blood flow.
Methods: OCT analysis of blood vessels was done in fixed human brain specimens and in an in vivo model system. The three dimensional architecture of human cerebral blood vessels was studied by a novel high resolution and high speed swept-source OCT device. Doppler-OCT was performed based on the conventional OCT signal using a phase difference scanning software.
Results: Blood vessels could be analyzed in their native environment without the need for dissection by a no-touch technique. Data sets of large segments of major cerebral blood vessels could be acquired within seconds and reconstructed into three dimensional objects recreating a virtual image of the vascular anatomy. The normal microstructure of the vascular wall as well as pathologies such as plaques or stenoses could be visualized and measured. Blood vessels down to capillary size could be detected. The blood flow was visualized using Doppler-OCT without the application of contrast enhancing agents. Color coding of blood flow velocity allowed a differentiation between arterial and venous blood vessels.
Conclusions: We have demonstrated that OCT can provide cross sectional images of normal and pathological blood vessels in the brain. Three dimensional reconstruction of sequential images allows a display of the vascular anatomy. Doppler-OCT can visualize and quantify blood flow. Calibration of the phase difference analysis may soon provide exact blood velocity data. This may allow detection of hyperemic regions within tumor tissue for example, as well as blood flow measurements in neurovascular settings such as aneurysm surgery.