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Xie Z, Wang G, Cheng Y, Zhang Q, Le MN, Wang RK. Optical coherence tomography angiography measures blood pulsatile waveforms at variable tissue depths. Quant Imaging Med Surg 2020; 11:907-917. [PMID: 33654664 DOI: 10.21037/qims-20-778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Photoplethysmography (PPG) is routinely used to detect the blood pulse signal from skin tissue beds in clinics. However, the origin of the PPG signal remains controversial. The purpose of this study is to explore optical coherence tomography angiography (OCTA) to indicate pulsatile waveforms in the papillary plexus and dermal plexus separately under different hand elevations. Method Optical microangiography (OMAG) algorithm was used to obtain a 3D OCTA signals, from which the depth-resolved pulsatile blood flow signals were extracted from different skin vascular plexus. The systolic amplitude, crest time, and delta T were measured from the OCTA pulsatile signals when the hand was placed at the positions of 50 cm below, 0 cm, and 50 cm above the heart level. Results The pulse signal integrated from all the depths has a similar waveform to that of the PPG and showed the same morphological change at different hand elevations. The pulsatile patterns from the papillary plexus and dermal plexus showed distinct morphological changes at different local blood pressure. Less amplitude difference was found from papillary plexus comparing to that of the dermal plexus. Crest time was found in an increasing trend in the OCTA pulsatile waveform from both plexuses when the arm was raised from the position below to above the heart level. In contrast, a decreasing trend of Delta T was detected in the dermal pulsatile but was not observed from that of the papillary plexus, indicating that vascular resistance associated with the arm elevations does not necessarily have the same effect on the two plexuses. Conclusions OCTA can provide depth-resolved pulsatile waveforms within different microvascular plexus within tissue skin beds. This technique could open doors to understanding the mechanisms of how blood flow changes at different skin circulatory plexus.
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Affiliation(s)
- Zhiying Xie
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Geng Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Yuxuan Cheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Minh Nhan Le
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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Mastropasqua R, D’Aloisio R, Agnifili L, Zuppardi E, Di Marzio G, Di Nicola M, Porreca A, Guarini D, Totta M, Brescia L, Di Antonio L. Functional and Structural Reliability of Optic Nerve Head Measurements in Healthy Eyes by Means of Optical Coherence Tomography Angiography. ACTA ACUST UNITED AC 2020; 56:medicina56010044. [PMID: 31968630 PMCID: PMC7023288 DOI: 10.3390/medicina56010044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/09/2020] [Accepted: 01/14/2020] [Indexed: 12/03/2022]
Abstract
Background and Objectives: the aim of the study was to evaluate the repeatability and reproducibility of optical microangiography (OMAG)-based optical coherence tomography angiography (OCTA) in the optic nerve head (ONH) and radial peripapillary capillary (RPC) perfusion assessment of healthy eyes. Materials and Methods: in this observational study, a total of 40 healthy subjects underwent ONH evaluation, using an OMAG-based OCTA system at baseline (T0), after 30 min (T1), and after 7 days (T2). The main outcome measures were the vessel density (VD) and flux index (FI) of the RPCs, as well as peri-papillary retinal nerve fibre layer (pRNFL) thickness. The analysis was performed by two observers independently. The coefficient of repeatability (CR), within the subject coefficient of variation (CVw) and intrasession correlation coefficient (ICC), to evaluate intrasession repeatability of measurements was calculated for each observer. Results: the high intrasession and intersession repeatability and reproducibility were assessed in the two observers for all three outcome measures. Of note, the CRs for the first and the second observer were 0.011 (95% confidence interval (CI) 0.009–0.014) and 0.016 (95% CI 0.013–0.020) for FI, 0.016 (95% CI 0.013–0.021) and 0.017 (95% CI 0.014–0.021) for VD, and 2.400 (95% CI 1.948–3.092) and 3.732 (95% CI 3.064–4.775) for pRNFL thickness, respectively. The agreement between them was excellent for pRNFL assessment and very good for FI and VD. Conclusion: OCTA has a great potential in the accurate assessment of ONH and peri-papillary microcirculation. It allows for repeated and reproducible measurements without multiple scans-related bias, thus guaranteeing an independent operator analysis with good reproducibility and repeatability.
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Affiliation(s)
- Rodolfo Mastropasqua
- Vitreoretinal Unit, Bristol Eye Hospital, University of Bristol, Bristol BS8 1TH, UK;
- Eye Clinic, Polytechnic University of Marche, 60126 Ancona, Italy
| | - Rossella D’Aloisio
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
- Correspondence: ; Tel.: +39-087-135-8410; Fax: +39-087-135-7294
| | - Luca Agnifili
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
| | - Eduardo Zuppardi
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
| | - Guido Di Marzio
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
| | - Marta Di Nicola
- Laboratory of Biostatistics, Department of Medical, Oral and Biotechnological Sciences, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy;
| | - Annamaria Porreca
- Department of Economic Studies, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy;
| | - Daniele Guarini
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
| | - Michele Totta
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
| | - Lorenza Brescia
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
| | - Luca Di Antonio
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy; (L.A.); (E.Z.); (G.D.M.); (D.G.); (M.T.); (L.B.); (L.D.A.)
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Li W, Li P, Fang Y, Lei TC, Dong K, Zou J, Gong W, Xie S, Huang Z. Quantitative assessment of skin swelling using optical coherence tomography. Photodiagnosis Photodyn Ther 2019; 26:413-419. [DOI: 10.1016/j.pdpdt.2019.04.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
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Choi J, Kwon J, Shin JW, Lee J, Lee S, Kook MS. Quantitative optical coherence tomography angiography of macular vascular structure and foveal avascular zone in glaucoma. PLoS One 2017; 12:e0184948. [PMID: 28934255 PMCID: PMC5608222 DOI: 10.1371/journal.pone.0184948] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/02/2017] [Indexed: 01/28/2023] Open
Abstract
Objective The study aimed to evaluate the quantitative characteristics of the macular vessel density (VD) and foveal avascular zone (FAZ) in glaucoma using optical coherence tomography angiography (OCT-A). Design Cross-sectional, age- and sex-matched case–control study. Methods Fifty-two eyes of 52 patients with primary open angle glaucoma and 52 eyes from 52 healthy participants were recruited retrospectively. OCT-A was performed on a 3 x 3-mm macular region centered on the fovea. OCT-A scans were manually graded to define the FAZ. Parafoveal VD in superficial and deep retina were analyzed in the circular- and quadrant-segmented zone. The FAZ parameters included size, perimeter, and circularity index. The regression analysis among VD and FAZ-related parameters and ocular parameters was performed, and the diagnostic ability was calculated with refractive error adjusted. Results For both groups, the mean age and the sex ratio was not different between groups. With refractive error adjusted, the average macular VD was lower in glaucoma than in the control group for superficial (P = 0.013), deep (P<0.001), and the whole retina (P = 0.002). There were increased FAZ perimeter and decreased FAZ circularity index in glaucoma when compared with controls (P<0.001). In the multivariate regression models, FAZ circularity index were significantly associated with decreased peripapillary RNFL thickness (P = 0.007) and macular GCIPL thickness (P = 0.009) measured by OCT. The refractive-error adjusted area under receiver operating characteristics was highest for FAZ circularity index (0.905; 95% CI, 0.844–0.966), followed by temporal deep retinal VD (0.870; 95% CI, 0.803–0.937) and FAZ perimeter (0.858; 95% CI, 0.784–0.932). Conclusions Decreased macular VD, increased FAZ perimeter, and decreased FAZ circularity index were observed in eyes with glaucoma using OCT-A. With refractive error adjusted, these parameters showed considerable diagnostic value for glaucoma. FAZ circularity index may be a novel biomarker representing disruption of the parafoveal capillary network in glaucoma, as supported by its association with structural parameters.
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Affiliation(s)
- Jaewan Choi
- Central Seoul Eye Center, Seoul, Republic of Korea
| | - Junki Kwon
- Department of Ophthalmology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Joong Won Shin
- Department of Ophthalmology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Jiyun Lee
- Department of Ophthalmology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Saem Lee
- Central Seoul Eye Center, Seoul, Republic of Korea
| | - Michael S. Kook
- Department of Ophthalmology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
- * E-mail:
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Kashani AH, Chen CL, Gahm JK, Zheng F, Richter GM, Rosenfeld PJ, Shi Y, Wang RK. Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications. Prog Retin Eye Res 2017; 60:66-100. [PMID: 28760677 PMCID: PMC5600872 DOI: 10.1016/j.preteyeres.2017.07.002] [Citation(s) in RCA: 567] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 02/06/2023]
Abstract
OCT has revolutionized the practice of ophthalmology over the past 10-20 years. Advances in OCT technology have allowed for the creation of novel OCT-based methods. OCT-Angiography (OCTA) is one such method that has rapidly gained clinical acceptance since it was approved by the FDA in late 2016. OCTA images are based on the variable backscattering of light from the vascular and neurosensory tissue in the retina. Since the intensity and phase of backscattered light from retinal tissue varies based on the intrinsic movement of the tissue (e.g. red blood cells are moving, but neurosensory tissue is static), OCTA images are essentially motion-contrast images. This motion-contrast imaging provides reliable, high resolution, and non-invasive images of the retinal vasculature in an efficient manner. In many cases, these images are approaching histology level resolution. This unprecedented resolution coupled with the simple, fast and non-invasive imaging platform have allowed a host of basic and clinical research applications. OCTA demonstrates many important clinical findings including areas of macular telangiectasia, impaired perfusion, microaneurysms, capillary remodeling, some types of intraretinal fluid, and neovascularization among many others. More importantly, OCTA provides depth-resolved information that has never before been available. Correspondingly, OCTA has been used to evaluate a spectrum of retinal vascular diseases including diabetic retinopathy (DR), retinal venous occlusion (RVO), uveitis, retinal arterial occlusion, and age-related macular degeneration among others. In this review, we will discuss the methods used to create OCTA images, the practical applications of OCTA in light of invasive dye-imaging studies (e.g. fluorescein angiography) and review clinical studies demonstrating the utility of OCTA for research and clinical practice.
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Affiliation(s)
- Amir H Kashani
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of University of Southern California; Los Angeles, CA 90033, United States.
| | - Chieh-Li Chen
- Department of Biomedical Engineering, University of Washington Seattle, Seattle, WA 98195, United States
| | - Jin K Gahm
- Laboratory of Neuro Imaging (LONI), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, United States
| | - Fang Zheng
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL 33136, United States
| | - Grace M Richter
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of University of Southern California; Los Angeles, CA 90033, United States
| | - Philip J Rosenfeld
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL 33136, United States
| | - Yonggang Shi
- Laboratory of Neuro Imaging (LONI), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, United States
| | - Ruikang K Wang
- Department of Biomedical Engineering, University of Washington Seattle, Seattle, WA 98195, United States
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Chen CL, Zhang A, Bojikian KD, Wen JC, Zhang Q, Xin C, Mudumbai RC, Johnstone MA, Chen PP, Wang RK. Peripapillary Retinal Nerve Fiber Layer Vascular Microcirculation in Glaucoma Using Optical Coherence Tomography-Based Microangiography. Invest Ophthalmol Vis Sci 2017; 57:OCT475-85. [PMID: 27442341 PMCID: PMC4968914 DOI: 10.1167/iovs.15-18909] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Purpose To investigate the vascular microcirculation changes in the retinal nerve fiber layer (RNFL) in normal, glaucoma suspect, and open-angle glaucoma (OAG) groups using optical coherence tomography–based microangiography (OMAG). Methods One eye from each subject was scanned with a Cirrus HD-OCT 5000–based OMAG prototype system montage scanning protocol centered at the optic nerve head (ONH). Blood flow signals were extracted using OMAG algorithm. Retinal nerve fiber layer vascular microcirculation was measured by calculating the blood flux index and vessel area density within a 1.2-mm width annulus centered at the ONH with exclusion of big retinal vessels. One-way ANOVA were performed to analyze the RNFL microcirculation among groups. Linear-regression models were constructed to analyze the correlation between RNFL microcirculation and clinical parameters. Discrimination capabilities of the flow metrics were assessed with the area under the receiver operating characteristic curve (AROC). Results Twenty normal, 26 glaucoma suspect, and 42 OAG subjects were enrolled. Eyes from OAG subjects and glaucoma suspects showed significantly lower blood flux index compared with normal eyes (P ≤ 0.0015). Retinal nerve fiber layer blood flow metrics showed significant correlations with visual field indices and structural changes in glaucomatous eyes (P ≤ 0.0123). Similar discrimination capability of blood flux index compared with RNFL thickness was found in both disease groups. Conclusions Peripapillary RNFL vascular microcirculation measured as blood flux index by OMAG showed significant differences among OAG, glaucoma suspect, and normal controls and was significantly correlated with functional and structural defects. Retinal nerve fiber layer microcirculation measurement using OMAG may help physicians monitor glaucoma.
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Affiliation(s)
- Chieh-Li Chen
- Department of Bioengineering, University of Washington, Seattle, Washington, United States 2Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Anqi Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Karine D Bojikian
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Joanne C Wen
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Chen Xin
- Department of Bioengineering, University of Washington, Seattle, Washington, United States 3Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Raghu C Mudumbai
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Murray A Johnstone
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Philip P Chen
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States 2Department of Ophthalmology, University of Washington, Seattle, Washington, United States
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Wang RK, Zhang Q, Li Y, Song S. Optical coherence tomography angiography-based capillary velocimetry. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:66008. [PMID: 28617921 PMCID: PMC5472241 DOI: 10.1117/1.jbo.22.6.066008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/19/2017] [Indexed: 05/05/2023]
Abstract
Challenge persists in the field of optical coherence tomography (OCT) when it is required to quantify capillary blood flow within tissue beds in vivo. We propose a useful approach to statistically estimate the mean capillary flow velocity using a model-based statistical method of eigendecomposition (ED) analysis of the complex OCT signals obtained with the OCT angiography (OCTA) scanning protocol. ED-based analysis is achieved by the covariance matrix of the ensemble complex OCT signals, upon which the eigenvalues and eigenvectors that represent the subsets of the signal makeup are calculated. From this analysis, the signals due to moving particles can be isolated by employing an adaptive regression filter to remove the eigencomponents that represent static tissue signals. The mean frequency (MF) of moving particles can be estimated by the first lag-one autocorrelation of the corresponding eigenvectors. Three important parameters are introduced, including the blood flow signal power representing the presence of blood flow (i.e., OCTA signals), the MF indicating the mean velocity of blood flow, and the frequency bandwidth describing the temporal flow heterogeneity within a scanned tissue volume. The proposed approach is tested using scattering phantoms, in which microfluidic channels are used to simulate the functional capillary vessels that are perfused with the scattering intralipid solution. The results indicate a linear relationship between the MF and mean flow velocity. In vivo animal experiments are also conducted by imaging mouse brain with distal middle cerebral artery ligation to test the capability of the method to image the changes in capillary flows in response to an ischemic insult, demonstrating the practical usefulness of the proposed method for providing important quantifiable information about capillary tissue beds in the investigations of neurological conditions in vivo.
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Affiliation(s)
- Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
- Address all correspondence to: Ruikang K. Wang, E-mail:
| | - Qinqin Zhang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Yuandong Li
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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Chen CL, Wang RK. Optical coherence tomography based angiography [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1056-1082. [PMID: 28271003 PMCID: PMC5330554 DOI: 10.1364/boe.8.001056] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/16/2017] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT)-based angiography (OCTA) provides in vivo, three-dimensional vascular information by the use of flowing red blood cells as intrinsic contrast agents, enabling the visualization of functional vessel networks within microcirculatory tissue beds non-invasively, without a need of dye injection. Because of these attributes, OCTA has been rapidly translated to clinical ophthalmology within a short period of time in the development. Various OCTA algorithms have been developed to detect the functional micro-vasculatures in vivo by utilizing different components of OCT signals, including phase-signal-based OCTA, intensity-signal-based OCTA and complex-signal-based OCTA. All these algorithms have shown, in one way or another, their clinical values in revealing micro-vasculatures in biological tissues in vivo, identifying abnormal vascular networks or vessel impairment zones in retinal and skin pathologies, detecting vessel patterns and angiogenesis in eyes with age-related macular degeneration and in skin and brain with tumors, and monitoring responses to hypoxia in the brain tissue. The purpose of this paper is to provide a technical oriented overview of the OCTA developments and their potential pre-clinical and clinical applications, and to shed some lights on its future perspectives. Because of its clinical translation to ophthalmology, this review intentionally places a slightly more weight on ophthalmic OCT angiography.
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Affiliation(s)
- Chieh-Li Chen
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, 325 9th Ave, Seattle, WA 98104, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, 325 9th Ave, Seattle, WA 98104, USA
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Qin W, Roberts MA, Qi X, Murry CE, Zheng Y, Wang RK. Depth-resolved 3D visualization of coronary microvasculature with optical microangiography. Phys Med Biol 2016; 61:7536-7550. [PMID: 27716639 DOI: 10.1088/0031-9155/61/21/7536] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In this study, we propose a novel implementation of optical coherence tomography-based angiography combined with ex vivo perfusion of fixed hearts to visualize coronary microvascular structure and function. The extracorporeal perfusion of Intralipid solution allows depth-resolved angiographic imaging, control of perfusion pressure, and high-resolution optical microangiography. The imaging technique offers new opportunities for microcirculation research in the heart, which has been challenging due to motion artifacts and the lack of independent control of pressure and flow. With the ability to precisely quantify structural and functional features, this imaging platform has broad potential for the study of the pathophysiology of microvasculature in the heart as well as other organs.
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Affiliation(s)
- Wan Qin
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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Hwang TS, Gao SS, Liu L, Lauer AK, Bailey ST, Flaxel CJ, Wilson DJ, Huang D, Jia Y. Automated Quantification of Capillary Nonperfusion Using Optical Coherence Tomography Angiography in Diabetic Retinopathy. JAMA Ophthalmol 2016; 134:367-73. [PMID: 26795548 DOI: 10.1001/jamaophthalmol.2015.5658] [Citation(s) in RCA: 257] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
IMPORTANCE Macular ischemia is a key feature of diabetic retinopathy (DR). Quantification of macular ischemia has potential as a biomarker for DR. OBJECTIVE To assess the feasibility of automated quantification of capillary nonperfusion as a potential sign of macular ischemia using optical coherence tomography (OCT) angiography. DESIGN, SETTING, AND PARTICIPANTS An observational study conducted in a tertiary, subspecialty, academic practice evaluated macular nonperfusion with 6 × 6-mm OCT angiography obtained with commercially available 70-kHz OCT and fluorescein angiography (FA). The study was conducted from January 22 to September 18, 2014. Data analysis was performed from October 1, 2014, to April 7, 2015. Participants included 12 individuals with normal vision serving as controls and 12 patients with various levels of DR. MAIN OUTCOMES AND MEASURES Preplanned primary measures were parafoveal and perifoveal vessel density, total avascular area, and foveal avascular zone as detected with 6 × 6-mm OCT angiography and analyzed using an automated algorithm. Secondary measures included the agreement of the avascular area between the OCT angiogram and FA. RESULTS Compared with the 12 healthy controls (11 women; mean [SD] age, 54.2 [14.2] years), the 12 participants with DR (4 women; mean [SD] age, 55.1 [12.1] years) had reduced parafoveal and perifoveal vessel density by 12.6% (95% CI, 7.7%-17.5%; P < .001) and 10.4% (95% CI, 6.8%-14.1%; P < .001), respectively. Total avascular area and foveal avascular zone area were greater in eyes with DR by 0.82 mm2 (95% CI, 0.65-0.99 mm2; P = .02) and 0.16 mm2 (95% CI, 0.05-0.28 mm2; P < .001). The agreement between the vascular areas in the OCT angiogram and FA had a κ value of 0.45 (95% CI, 0.21-0.70; P < .001). Total avascular area in the central 5.5-mm-diameter area distinguished eyes with DR from control eyes with 100% sensitivity and specificity. CONCLUSIONS AND RELEVANCE Avascular area analysis with an automated algorithm using OCT angiography, although not equivalent to FA, detected DR reliably in this small pilot study. Further study is necessary to determine the usefulness of the automated quantification in clinical practice.
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Affiliation(s)
- Thomas S Hwang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Simon S Gao
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Liang Liu
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Andreas K Lauer
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Steven T Bailey
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Christina J Flaxel
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - David J Wilson
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
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Chen CL, Bojikian KD, Xin C, Wen JC, Gupta D, Zhang Q, Mudumbai RC, Johnstone MA, Chen PP, Wang RK. Repeatability and reproducibility of optic nerve head perfusion measurements using optical coherence tomography angiography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:65002. [PMID: 27272095 PMCID: PMC4896902 DOI: 10.1117/1.jbo.21.6.065002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/19/2016] [Indexed: 05/29/2023]
Abstract
Optical coherence tomography angiography (OCTA) has increasingly become a clinically useful technique in ophthalmic imaging. We evaluate the repeatability and reproducibility of blood perfusion in the optic nerve head (ONH) measured using optical microangiography (OMAG)-based OCTA. Ten eyes from 10 healthy volunteers are recruited and scanned three times with a 68-kHz Cirrus HD-OCT 5000-based OMAG prototype system (Carl Zeiss Meditec Inc., Dublin, California) centered at the ONH involving two separate visits within six weeks. Vascular images are generated with OMAG processing by detecting the differences in OCT signals between consecutive B-scans acquired at the same retina location. ONH perfusion is quantified as flux, vessel area density, and normalized flux within the ONH for the prelaminar, lamina cribrosa, and the full ONH. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) are used to evaluate intravisit and intervisit repeatability, and interobserver reproducibility. ONH perfusion measurements show high repeatability [CV≤3.7% (intravisit) and ≤5.2% (intervisit)] and interobserver reproducibility (ICC≤0.966) in all three layers by three metrics. OCTA provides a noninvasive method to visualize and quantify ONH perfusion in human eyes with excellent repeatability and reproducibility, which may add additional insight into ONH perfusion in clinical practice.
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Affiliation(s)
- Chieh-Li Chen
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Karine D. Bojikian
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Chen Xin
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Joanne C. Wen
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Divakar Gupta
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Qinqin Zhang
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Raghu C. Mudumbai
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Murray A. Johnstone
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Philip P. Chen
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
- University of Washington, Department of Ophthalmology, 908 Jefferson Street, Seattle, Washington 98104, United States
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Chen CL, Bojikian KD, Gupta D, Wen JC, Zhang Q, Xin C, Kono R, Mudumbai RC, Johnstone MA, Chen PP, Wang RK. Optic nerve head perfusion in normal eyes and eyes with glaucoma using optical coherence tomography-based microangiography. Quant Imaging Med Surg 2016; 6:125-33. [PMID: 27190764 DOI: 10.21037/qims.2016.03.05] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND To investigate the differences of perfusion in the optic nerve head (ONH) between normal and glaucomatous eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. METHODS One eye from each subject was scanned with a 68 kHz Cirrus 5000 HD-OCT-based OMAG prototype system centered at the ONH (Carl Zeiss Meditec Inc, Dublin, CA, USA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. En face OMAG images for preLC were generated using signals with highest blood flow signal intensity. ONH perfusion was quantified as flux, vessel area density, and normalized flux within the ONH. Standard t-tests were performed to analyze the ONH perfusion differences between normal and glaucomatous eyes. Linear regression models were constructed to analyze the correlation between ONH perfusion and other clinical measurements. RESULTS Twenty normal and 21 glaucoma subjects were enrolled. Glaucomatous eyes had significantly lower ONH perfusion in preLC in all three perfusion metrics compared to normal eyes (P≤0.0003). Significant correlations between ONH perfusion and disease severity as well as structural changes were detected in glaucomatous eyes (P≤0.012). CONCLUSIONS ONH perfusion detected by OMAG showed significant differences between glaucoma and normal controls and was significantly correlated with disease severity and structural defects in glaucomatous eyes. ONH perfusion measurement using OMAG may provide useful information for detection and monitoring of glaucoma.
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Affiliation(s)
- Chieh-Li Chen
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Karine D Bojikian
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Divakar Gupta
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Joanne C Wen
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Qinqin Zhang
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Chen Xin
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Rei Kono
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Raghu C Mudumbai
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Murray A Johnstone
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Philip P Chen
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Ruikang K Wang
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
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Optic Disc Perfusion in Primary Open Angle and Normal Tension Glaucoma Eyes Using Optical Coherence Tomography-Based Microangiography. PLoS One 2016; 11:e0154691. [PMID: 27149261 PMCID: PMC4858256 DOI: 10.1371/journal.pone.0154691] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/18/2016] [Indexed: 01/14/2023] Open
Abstract
Purpose To investigate optic disc perfusion differences in normal, primary open-angle glaucoma (POAG), and normal tension glaucoma (NTG) eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. Design Cross-sectional, observational study. Subjects Twenty-eight normal, 30 POAG, and 31 NTG subjects. Methods One eye from each subject was scanned with a 68 kHz Cirrus HD-OCT 5,000-based OMAG prototype system centered at the optic nerve head (ONH) (Carl Zeiss Meditec Inc, Dublin, CA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. Main Outcome Measures Optic disc perfusion, quantified as flux, vessel area density, and normalized flux (flux normalized by the vessel area) within the ONH. Results Glaucomatous eyes had significantly lower optic disc perfusion in preLC in all three perfusion metrics (p<0.0001) compared to normal eyes. The visual field (VF) mean deviation (MD) and pattern standard deviation (PSD) were similar between the POAG and NTG groups, and no differences in optic disc perfusion were observed between POAG and NTG. Univariate analysis revealed significant correlation between optic disc perfusion and VF MD, VF PSD, and rim area in both POAG and NTG groups (p≤0.0288). However, normalized optic disc perfusion was correlated with some structural measures (retinal nerve fiber layer thickness and ONH cup/disc ratio) only in POAG eyes. Conclusions Optic disc perfusion detected with OMAG was significantly reduced in POAG and NTG groups compared to normal controls, but no difference was seen between POAG and NTG groups with similar levels of VF damage. Disc perfusion was significantly correlated with VF MD, VF PSD, and rim area in glaucomatous eyes. Vascular changes at the optic disc as measured using OMAG may provide useful information for diagnosis and monitoring of glaucoma.
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Chen CL, Bojikian KD, Gupta D, Wen JC, Zhang Q, Xin C, Kono R, Mudumbai RC, Johnstone MA, Chen PP, Wang RK. Optic nerve head perfusion in normal eyes and eyes with glaucoma using optical coherence tomography-based microangiography. Quant Imaging Med Surg 2016. [PMID: 31281779 DOI: 10.21037/qims] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND To investigate the differences of perfusion in the optic nerve head (ONH) between normal and glaucomatous eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. METHODS One eye from each subject was scanned with a 68 kHz Cirrus 5000 HD-OCT-based OMAG prototype system centered at the ONH (Carl Zeiss Meditec Inc, Dublin, CA, USA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. En face OMAG images for preLC were generated using signals with highest blood flow signal intensity. ONH perfusion was quantified as flux, vessel area density, and normalized flux within the ONH. Standard t-tests were performed to analyze the ONH perfusion differences between normal and glaucomatous eyes. Linear regression models were constructed to analyze the correlation between ONH perfusion and other clinical measurements. RESULTS Twenty normal and 21 glaucoma subjects were enrolled. Glaucomatous eyes had significantly lower ONH perfusion in preLC in all three perfusion metrics compared to normal eyes (P≤0.0003). Significant correlations between ONH perfusion and disease severity as well as structural changes were detected in glaucomatous eyes (P≤0.012). CONCLUSIONS ONH perfusion detected by OMAG showed significant differences between glaucoma and normal controls and was significantly correlated with disease severity and structural defects in glaucomatous eyes. ONH perfusion measurement using OMAG may provide useful information for detection and monitoring of glaucoma.
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Affiliation(s)
- Chieh-Li Chen
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Karine D Bojikian
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Divakar Gupta
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Joanne C Wen
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Qinqin Zhang
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Chen Xin
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Rei Kono
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Raghu C Mudumbai
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Murray A Johnstone
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Philip P Chen
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Ruikang K Wang
- 1 Department of Bioengineering, 2 Department of Ophthalmology, University of Washington, Seattle, WA, USA ; 3 Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
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Baran U, Wang RK. Review of optical coherence tomography based angiography in neuroscience. NEUROPHOTONICS 2016; 3:010902. [PMID: 26835484 PMCID: PMC4719095 DOI: 10.1117/1.nph.3.1.010902] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/14/2015] [Indexed: 05/09/2023]
Abstract
The brain is a complex ecosystem, consisting of multiple layers and tissue compartments. To facilitate the understanding of its function and its response to neurological insults, a fast in vivo imaging tool with a micron-level resolution, which can provide a field of view at a few millimeters, is desirable. Optical coherence tomography (OCT) is a noninvasive method for imaging three-dimensional biological tissues with high resolution ([Formula: see text]) and without a need for contrast agents. Recent development of OCT-based angiography has started to shed some new light on cerebral hemodynamics in neuroscience. We give an overview of the recent developments of OCT-based imaging techniques for neuroscience applications in rodents. We summarize today's technological alternatives for OCT-based angiography for neuroscience and provide a discussion of challenges and opportunities. Moreover, a summary of OCT angiography studies for stroke, traumatic brain injury, and subarachnoid hemorrhage cases on rodents is provided.
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Affiliation(s)
- Utku Baran
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
- University of Washington, Department of Electrical Engineering, 185 Stevens Way, Seattle, Washington 98195, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
- Address all correspondence to: Ruikang K. Wang, E-mail:
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Cherry SR, Ruffle J. Roberts Prize for the best paper published in 2014. Phys Med Biol 2015; 60:E1-2. [DOI: 10.1088/0031-9155/60/19/e1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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