High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

Abstract

Noninvasive microvascular imaging using optical coherence Doppler tomography (ODT) has shown great promise in brain studies; however, high-speed microcirculatory imaging in deep brain remains an open quest. A high-speed 1.3 μm swept-source ODT (SS-ODT) system is reported which was based on a 200 kHz vertical-cavity-surface-emitting laser. Phase errors induced by sweep-trigger desynchronization were effectively reduced by spectral phase encoding and instantaneous correlation among the A-scans. Phantom studies have revealed a significant reduction in phase noise, thus an enhancement of minimally detectable flow down to 268.2 μm/s. Further in vivo validation was performed, in which 3D cerebral-blood-flow (CBF) networks in mouse brain over a large field-of-view (FOV: 8.5 × 5 × 3.2 mm3) was scanned through thinned skull. Results showed that fast flows up to 3 cm/s in pial vessels and minute flows down to 0.3 mm/s in arterioles or venules were readily detectable at depths down to 3.2 mm. Moreover, the dynamic changes of the CBF networks elicited by acute cocaine such as heterogeneous responses in various vessel compartments and at different cortical layers as well as transient ischemic events were tracked, suggesting the potential of SS-ODT for brain functional imaging that requires high flow sensitivity and dynamic range, fast frame rate and a large FOV to cover different brain regions.

Micro-imaging of Brain Cancer Radiation Therapy Using Phase-contrast Computed Tomography

“…Furthermore, swept-source optical coherence Doppler tomography (SS-ODT), sensitive to dynamic and transient chances in 3D cerebral blood-flow, enables in-vivo functional micro-circulatory imaging of deep brain vasculature at depths down to 3.2mm 32 .…”

Optical Coherence Tomography: Basic Concepts and Applications in Neuroscience Research

“…However, high-speed microcirculatory imaging in deep brain with D-OCT or ODT remained an open quest. Recently, Chen et al (2016) have developed a 1.3 µ m high-speed swept source ODT (SS-ODT) system that was capable of detecting high-speed microcirculatory blood flow elucidated by acute cocaine in deep brain (see Figure 3 ) [ 47 ]. Figure 3 shows high-speed SS-ODT images for functional imaging of the CBF network dynamics in response to an acute cocaine challenge.…”

“…(b) En face and cross-sectional projections to show the flow dynamics in different vessels (e.g., 1–6) after cocaine. (c) Time-lapse CBF change (ΔCBF%) to track the dynamics of different vascular compartments (e.g., arterioles and venules) in response to cocaine (reprinted from [ 47 ]).…”

Akinetic swept-source optical coherence tomography based on a pulse-modulated active mode locking fiber laser for human retinal imaging

“…SS-OCT systems have advantages of a high imaging speed and longer imaging depth range with a simple and cost-effective detecting scheme (single photon detector) compared with other OCT systems, such as time domain-OCT and SD-OCT 7,11,13–17 . The characteristics of SS-OCT systems mainly depend on the performances of the wavelength-swept source.…”