A comparison of Doppler optical coherence tomography methods

Liu, Gangjun; Lin, Alexander; Tromberg, Bruce J.; Chen, Zhongping

doi:10.1364/boe.3.002669

Cited by 106 publications

(129 citation statements)

References 41 publications

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“…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).…”

Section: Discussionmentioning

confidence: 99%

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

Jia

Bailey

Hwang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

600

469

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Retinal vascular diseases are important causes of vision loss. A detailed evaluation of the vascular abnormalities facilitates diagnosis and treatment in these diseases. Optical coherence tomography (OCT) angiography using the highly efficient split-spectrum amplitude decorrelation angiography algorithm offers an alternative to conventional dye-based retinal angiography. OCT angiography has several advantages, including 3D visualization of retinal and choroidal circulations (including the choriocapillaris) and avoidance of dye injection-related complications. Results from six illustrative cases are reported. In diabetic retinopathy, OCT angiography can detect neovascularization and quantify ischemia. In age-related macular degeneration, choroidal neovascularization can be observed without the obscuration of details caused by dye leakage in conventional angiography. Choriocapillaris dysfunction can be detected in the nonneovascular form of the disease, furthering our understanding of pathogenesis. In choroideremia, OCT's ability to show choroidal and retinal vascular dysfunction separately may be valuable in predicting progression and assessing treatment response. OCT angiography shows promise as a noninvasive alternative to dye-based angiography for highly detailed, in vivo, 3D, quantitative evaluation of retinal vascular abnormalities.optical coherence tomography angiography | ophthalmic imaging | ocular circulation O ptical coherence tomography (OCT) has become the most commonly used imaging modality in ophthalmology. It provides cross-sectional and 3D imaging of the retina and optic nerve head with micrometer-scale depth resolution. Structural OCT enhances the clinician's ability to detect and monitor fluid exudation associated with retinal vascular diseases. Whereas anatomical alterations that impact vision are readily visible, structural OCT has a limited ability to image the retinal or choroidal vasculatures. Furthermore, it is unable to directly detect capillary dropout or pathologic new vessel growth (neovascularization) that are the major vascular changes associated with two of the leading causes of blindness, age-related macular degeneration (AMD) and diabetic retinopathy (1). To visualize these changes, traditional i.v. contrast dye-based angiography techniques are currently used.Fluorescein dye is primarily used to visualize the retinal vasculature. A separate dye, indocyanine green (ICG), is necessary to evaluate the choroidal vasculature. Both fluorescein angiography (FA) and ICG angiography require i.v. injection, which is time consuming, and which can cause nausea, vomiting, and, rarely, anaphylaxis (2). Dye leakage or staining provides information regarding vascular incompetence (e.g., from abnormal capillary growth), but it also obscures the image and blurs the boundaries of neovascularization. Additionally, conventional angiography is 2D, which makes it difficult to distinguish vascular abnormalities within different layers. Therefore, it is desirable to develop a no-injection, dye-free method...

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Section: Discussionmentioning

confidence: 99%

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

Jia

Bailey

Hwang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

600

469

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“…112,148,149 For flat vessel beds, signal variance calculations show a linear dependence on the flow. 150 Since most angiographic structures in skin, retina, or the choroicapillaries are parallel to the tissue surface, those methods are currently investigated in detail. Quantitative assessment of the velocity through signal correlation analysis needs, however, fast scan rates in order to avoid complete decorrelation of flow signals.…”

Section: Label-free Optical Angiographymentioning

confidence: 99%

Optical coherence tomography today: speed, contrast, and multimodality

Drexler¹,

Li²,

Kumar³

et al. 2014

J. Biomed. Opt

432

264

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Abstract. In the last 25 years, optical coherence tomography (OCT) has advanced to be one of the most innovative and most successful translational optical imaging techniques, achieving substantial economic impact as well as clinical acceptance. This is largely owing to the resolution improvements by a factor of 10 to the submicron regime and to the imaging speed increase by more than half a million times to more than 5 million A-scans per second, with the latter one accomplished by the state-of-the-art swept source laser technologies that are reviewed in this article. In addition, parallelization of OCT detection, such as line-field and full-field OCT, has shortened the acquisition time even further by establishing quasi-akinetic scanning. Besides the technical improvements, several functional and contrast-enhancing OCT applications have been investigated, among which the label-free angiography shows great potential for future studies. Finally, various multimodal imaging modalities with OCT incorporated are reviewed, in that these multimodal implementations can synergistically compensate for the fundamental limitations of OCT when it is used alone. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…11,20 The Doppler variance is only sensitive to motion perpendicular to the OCT beam and can be used to detect the transverse displacement. [21][22][23][24] At the green point, the shear wave from sub-source 1 travels along the blue dashed arrow and its vibration direction is along the blue solid-line arrow, and the shear wave from sub-source 2 travels along the red dashed arrow and its vibration direction is along the red solid-line arrow. Globally, the sum contribution of two vibrations is along the black solid-line arrow, and the shear wave propagates along the black solid-line arrow.…”

mentioning

confidence: 99%

Longitudinal shear wave imaging for elasticity mapping using optical coherence elastography

Zhu

Miao

et al. 2017

Applied Physics Letters

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Shear wave measurements for the determination of tissue elastic properties have been used in clinical diagnosis and soft tissue assessment. A shear wave propagates as a transverse wave where vibration is perpendicular to the wave propagation direction. Previous transverse shear wave measurements could detect the shear modulus in the lateral region of the force; however, they could not provide the elastic information in the axial region of the force. In this study, we report the imaging and quantification of longitudinal shear wave propagation using optical coherence tomography to measure the elastic properties along the force direction. The experimental validation and finite element simulations show that the longitudinal shear wave propagates along the vibration direction as a plane wave in the near field of a planar source. The wave velocity measurement can quantify the shear moduli in a homogeneous phantom and a side-by-side phantom. Combining the transverse shear wave and longitudinal shear wave measurements, this system has great potential to detect the directionally dependent elastic properties in tissues without a change in the force direction. Published by AIP Publishing. Elastography has provided a non-invasive imaging modality to assess the state of tissues and diseases by elastic properties of soft tissues since the mid-1990s. [1][2][3][4] The shear wave measurement is a quantitative method for the determination of elastic properties. For the shear wave measurement in elastography, a force source excites the tissue to induce a shear wave. The shear wave moves through the body of the tissue as a transverse wave where the vibration direction is perpendicular to the wave travel direction. An imaging system detects the vibration in the body to visualize the shear wave propagation. The shear modulus l can be quantitatively calculated from the shear wave velocity c by the following equation:where q is the tissue density. 5 Ultrasound imaging and magnetic resonance imaging have been used to image shear wave propagation in tissues. 6,7 However, the spatial resolutions of elastic maps are limited by the imaging technologies. Benefiting from the micrometer spatial resolution and millimeter penetration of optical coherence tomography (OCT), optical coherence elastography (OCE) based on the shear wave measurement has shown promising results in biomedical studies, including blood coagulation assessment, 8 ocular elasticity assessment, 4,9 and cardiac muscle measurement. 10 In an OCE application, an excitation from a force source, such as an ultrasonic transducer, 11-15 an airpuff device, 9 and a piezo-transducer (PZT), 16 is commonly applied to induce vibration, and OCT is used to detect the displacement and visualize the shear wave. Using shear wave elastography, the shear modulus is quantified by tracking the shear wave propagation. In previous measurements, the transverse shear wave propagates perpendicular to the force direction, so the shear modulus in the lateral region of the force can be quantified; 11-13 h...

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A comparison of Doppler optical coherence tomography methods

Cited by 106 publications

References 41 publications

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

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

Optical coherence tomography today: speed, contrast, and multimodality

Longitudinal shear wave imaging for elasticity mapping using optical coherence elastography

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