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Stuebiger N, Lee WH, Birtel J, Druchkiv V, Davis JL, DeBuc DC. Assessment of Blood Flow Velocity in Retinal Vasculitis Using the Retinal Function Imager-A Pilot Study. J Clin Med 2024; 13:3975. [PMID: 38999540 PMCID: PMC11242221 DOI: 10.3390/jcm13133975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 06/26/2024] [Accepted: 07/03/2024] [Indexed: 07/14/2024] Open
Abstract
Background: This pilot study aimed to evaluate the Retinal Function Imager (RFI) for visualizing retinal vasculature and assessment of blood flow characteristics in patients with retinal vasculitis. The RFI is a non-invasive imaging device measuring the blood flow velocity (BFV) in secondary and tertiary retinal vessels using hemoglobin as an intrinsic motion-contrast agent. Methods: To test the feasibility of the RFI for patients with retinal vasculitis, capillary perfusion maps (nCPMs) were generated from 15 eyes of eight patients (five females; mean age: 49 ± 12 years) with a mean uveitis duration of 74 ± 85 months. Five of these patients had birdshot chorioretinopathy, and three had primarily non-occlusive venous retinal vasculitis of unknown origin. To reflect that the BFV may be more reduced in patients with prolonged disease, patients were classified into a short-term (uveitis duration: 8-15 months) and a long-term uveitis group (uveitis duration: 60-264 months). Data were compared with healthy controls (16 eyes of 11 patients; mean age 45 ± 12 years; 8 females). Results: The mean BFV in the controls was 3.79 ± 0.50 mm/s in the retinal arteries and 2.35 ± 0.44 mm/s in the retinal veins, which was significantly higher compared to the retinal vasculitis group. Patients revealed an arterial BFV of 2.75 ± 0.74 mm/s (p < 0.001) and a venous BFV of 1.75 ± 0.51 mm/s (p = 0.016). In the short-term group, a trend towards a decreased venular and arteriolar BFV was seen, while a significant reduction was observed in the long-term group. The patients' microvasculature anatomy revealed by the nCPMs appeared unevenly distributed and a lower number of blood vessels were seen, along with a lower degree of complexity of their branching patterns, when compared with controls. Conclusions: This study demonstrated a reduction in venular and arteriolar BFVs in patients with retinal vasculitis. BFV alterations were already observed in early disease stages and became more pronounced in progressed disease. Additionally, we showed that retinal microvasculature changes may be observed by nCPMs. Retinal imaging with the RFI may serve as a diagnostic and quantifying tool in retinal vasculitis.
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Affiliation(s)
- Nicole Stuebiger
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Wen-Hsiang Lee
- Bascom Palmer Eye Institute, University of Miami, Miami, FL 33136, USA
| | - Johannes Birtel
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- Department of Ophthalmology, University of Bonn, 53127 Bonn, Germany
| | - Vasyl Druchkiv
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Janet L Davis
- Bascom Palmer Eye Institute, University of Miami, Miami, FL 33136, USA
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Su D, Garg S. The retinal function imager and clinical applications. EYE AND VISION 2018; 5:20. [PMID: 30123814 PMCID: PMC6088417 DOI: 10.1186/s40662-018-0114-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/28/2018] [Indexed: 12/19/2022]
Abstract
Background The Retinal Function Imager (RFI) provides in vivo and noninvasive imaging of both the retinal structure and function. Review The RFI can create capillary perfusion maps, measure blood flow velocity, and determine metabolic function including blood oximetry. It can aid clinical diagnosis as well as assess treatment response in several retinal vascular diseases including diabetic retinopathy. Blood flow velocity abnormalities have also been implicated in disease such as age-related macular degeneration and require further investigation. Compared with optical coherence tomography angiography, the RFI produces capillary maps of comparable image quality and wider field of view but it is unable to provide depth-resolved information and has longer image acquisition time. Currently, functional imaging using blood oximetry has limited applications and additional research is required. Conclusion The RFI offers noninvasive, high-resolution imaging of retinal microvasculature by creating capillary perfusion maps. In addition, it is capable of measuring retinal blood velocity directly and performs functional imaging with retinal blood oximetry. Its clinical applications are broad and additional research with functional imaging may potentially lead to diagnosis of diseases and their progression before anatomic abnormalities become evident, but longer image acquisition times may limit its clinical adoption.
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Affiliation(s)
- Daniel Su
- The Retina Service of Wills Eye Hospital, Mid Atlantic Retina, 840 Walnut Street, Suite 1020, Philadelphia, PA 19107 USA
| | - Sunir Garg
- The Retina Service of Wills Eye Hospital, Mid Atlantic Retina, 840 Walnut Street, Suite 1020, Philadelphia, PA 19107 USA
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Wang L, Jiang H, Grinvald A, Jayadev C, Wang J. A Mini Review of Clinical and Research Applications of the Retinal Function Imager. Curr Eye Res 2018; 43:273-288. [PMID: 29308926 DOI: 10.1080/02713683.2017.1414853] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To review the clinical applications and diagnostic value of the retinal function imager (RFI), briefly compare RFI to other optical imaging devices, and to describe recent developments. METHODS The search words "Retinal Functional Imager," "optical imaging," "retina angiography," "avascular zone," "foveal avascular zone," and other closely related terms were used in PubMed to review current literature involving the RFI. RESULTS The functions of the RFI were utilized in over 44 microvascular studies, which reported that the microvasculature may alter in velocity, morphology, and oximetry when affected by a number of ocular, neurological, or systemic diseases. Recently developed automatic algorithms for noninvasive angiography of large retinal regions, segmenting vessels, measuring blood flow, blood velocity, vessel diameter, and oximetry may enhance the clinical applications of the RFI. CONCLUSION The RFI has been used to characterize the retinal microvasculature under various conditions of all prevalent retinal diseases in addition to some central nerve system (CNS) and systemic diseases. Applying the RFI in research and clinical settings should help earlier diagnosis, support disease prevention, and improve treatment management.
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Affiliation(s)
- Liang Wang
- a Department of Biology, Krieger School of Arts and Sciences , Johns Hopkins University , Baltimore , MA , USA
| | - Hong Jiang
- b Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami , Miami , FL , USA.,c Department of Neurology , University of Miami , Miami , FL , USA
| | - Amiram Grinvald
- d Department of Neurobiology , Weizmann Institute of Science , Rehovot , Israel
| | | | - Jianhua Wang
- b Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami , Miami , FL , USA
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Abramoff MD, Fort PE, Han IC, Jayasundera KT, Sohn EH, Gardner TW. Approach for a Clinically Useful Comprehensive Classification of Vascular and Neural Aspects of Diabetic Retinal Disease. Invest Ophthalmol Vis Sci 2018; 59:519-527. [PMID: 29372250 PMCID: PMC5786342 DOI: 10.1167/iovs.17-21873] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 10/08/2017] [Indexed: 11/24/2022] Open
Abstract
The Early Treatment Diabetic Retinopathy Study (ETDRS) and other standardized classification schemes have laid a foundation for tremendous advances in the understanding and management of diabetic retinopathy (DR). However, technological advances in optics and image analysis, especially optical coherence tomography (OCT), OCT angiography (OCTa), and ultra-widefield imaging, as well as new discoveries in diabetic retinal neuropathy (DRN), are exposing the limitations of ETDRS and other classification systems to completely characterize retinal changes in diabetes, which we term diabetic retinal disease (DRD). While it may be most straightforward to add axes to existing classification schemes, as diabetic macular edema (DME) was added as an axis to earlier DR classifications, doing so may make these classifications increasingly complicated and thus clinically intractable. Therefore, we propose future research efforts to develop a new, comprehensive, and clinically useful classification system that will identify multimodal biomarkers to reflect the complex pathophysiology of DRD and accelerate the development of therapies to prevent vision-threatening DRD.
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Affiliation(s)
- Michael D. Abramoff
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
- Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States
- Iowa City VA Health Care System, Iowa City, Iowa, United States
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States
| | - Patrice E. Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Ian C. Han
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
- Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States
| | - K. Thiran Jayasundera
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Elliott H. Sohn
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
- Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States
| | - Thomas W. Gardner
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
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Tian J, Somfai GM, Campagnoli TR, Smiddy WE, Debuc DC. Interactive retinal blood flow analysis of the macular region. Microvasc Res 2015; 104:1-10. [PMID: 26569349 DOI: 10.1016/j.mvr.2015.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/19/2015] [Accepted: 11/08/2015] [Indexed: 12/21/2022]
Abstract
The study of retinal hemodynamics plays an important role to understand the onset and progression of diabetic retinopathy. In this work, we developed an interactive retinal analysis tool to quantitatively measure the blood flow velocity (BFV) and blood flow rate (BFR) in the macular region using the Retinal Function Imager (RFI). By employing a high definition stroboscopic fundus camera, the RFI device is able to assess retinal blood flow characteristics in vivo. However, the measurements of BFV using a user-guided vessel segmentation tool may induce significant inter-observer differences and BFR is not provided in the built-in software. In this work, we have developed an interactive tool to assess the retinal BFV and BFR in the macular region. Optical coherence tomography data was registered with the RFI image to locate the fovea accurately. The boundaries of the vessels were delineated on a motion contrast enhanced image and BFV was computed by maximizing the cross-correlation of pixel intensities in a ratio video. Furthermore, we were able to calculate the BFR in absolute values (μl/s). Experiments were conducted on 122 vessels from 5 healthy and 5 mild non-proliferative diabetic retinopathy (NPDR) subjects. The Pearson's correlation of the vessel diameter measurements between our method and manual labeling on 40 vessels was 0.984. The intraclass correlation (ICC) of BFV between our proposed method and built-in software was 0.924 and 0.830 for vessels from healthy and NPDR subjects, respectively. The coefficient of variation between repeated sessions was reduced significantly from 22.5% to 15.9% in our proposed method (p<0.001).
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Affiliation(s)
- Jing Tian
- Bascom Palmer Eye Institute, 900 NW 17th Street, Miami, FL 33136, USA,.
| | - Gábor Márk Somfai
- Bascom Palmer Eye Institute, 900 NW 17th Street, Miami, FL 33136, USA,; Department of Ophthalmology, Semmelweis University, Budapest, Üllői út 26, 1085, Hungary.
| | | | - William E Smiddy
- Bascom Palmer Eye Institute, 900 NW 17th Street, Miami, FL 33136, USA,.
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