Three dimensional optical angiography

Abstract

With existing optical imaging techniques three-dimensional (3-D) mapping of microvascular perfusion within tissue beds is severely limited by the efficient scattering and absorption of light by tissue. To overcome these limitations we have developed a method of optical angiography (OAG) that can generate 3-D angiograms within millimeter tissue depths by analyzing the endogenous optical scattering signal from an illuminated sample. The technique effectively separates the moving and static scattering elements within tissue to achieve high resolution images of blood flow, mapped into the 3-D optically sectioned tissue beds, at speeds that allow for perfusion assessment in vivo. Its development has its origin in Fourier domain optical coherence tomography. We used OAG to visualize the cerebral microcirculation, of adult living mice through the intact cranium, measurements which would be difficult, if not impossible, with other optical imaging techniques.

Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye

“…The color-coded angiogram can be superimposed on a gray-scale, cross-sectional, structural OCT image to demonstrate blood flow and structural information simultaneously. Flow projection artifacts are a common problem for existing OCT angiography techniques (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). To better distinguish and interpret the blood flow within different layers, a negative filter was used to mask projection artifacts from the larger caliber retinal vessels (24).…”

“…Initially, Doppler OCT angiography methods were investigated for the visualization and measurement of blood flow (3)(4)(5)(6)(7)(8). Because Doppler OCT is only sensitive to motion parallel to the OCT probe beam, it is limited in its ability to image retinal and choroidal circulations, which are predominantly perpendicular to the OCT beam.…”

Optical coherence tomography for the quantitative study of cerebrovascular physiology

“…Doppler OCT velocity axial projections can be used to perform absolute measurements of blood flow either by estimating vessel angles (Wang et al, 2007b) or by processing volumetric data (Srinivasan et al, 2010b). Optical coherence tomography angiography has also been developed to visualize red blood cell (RBC) perfusion (Wang et al, 2007a). Variations of this method have been shown to visualize perfusion with improved sensitivity and resolution (Srinivasan et al, 2010a;Vakoc et al, 2009).…”

Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter

“…OCT angiography (OCTA) has been used to visualize three-dimensional (3D) microvasculature using the Doppler effect to isolate blood flow from the static tissue [25,26]. OCTA was later performed using motion contrast, by calculating the amplitude, phase, or complex amplitude variation of the OCT signals between neighboring B-scan frames [27].…”