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Abdel-Kader AA, Ramsey DJ, Yussuf WA, Mohalhal AA, Eldaly MA, Elnahry AG. Diabetic microaneurysms detected by fluorescein angiography spatially correlate with regions of macular ischemia delineated by optical coherence tomography angiography. Indian J Ophthalmol 2023; 71:3085-3090. [PMID: 37530285 PMCID: PMC10538827 DOI: 10.4103/ijo.ijo_3155_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/20/2023] [Accepted: 06/01/2023] [Indexed: 08/03/2023] Open
Abstract
Purpose To characterize the relationship between diabetic macular ischemia (DMI) delineated by optical coherence tomography angiography (OCTA) and microaneurysms (MAs) identified by fundus fluorescein angiography (FFA). Methods Patients with diabetic retinopathy (DR) who underwent OCTA and FFA were retrospectively identified. FFA images were cropped and aligned with their respective OCTA images using i2k Align Retina software (Dual-Align, Clifton Park, NY, USA). Foveal avascular zone (FAZ) and ischemic areas were manually delineated on OCTA images, and MAs were marked on the corresponding FFA images before overlaying paired scans for analysis (ImageJ; National Institutes of Health, Bethesda, MD, USA). Results Twenty-eight eyes of 20 patients were included. The average number of MAs identified in cropped FFA images was 127 ± 42. More DMI was noted in the superficial capillary plexus (SCP; 36 ± 13%) compared to the deep capillary plexus (DCP; 28 ± 14%, P < 0.001). Similarly, more MAs were associated with ischemic areas in SCP compared to DCP (92.0 ± 35.0 vs. 76.8 ± 36.5, P < 0.001). Most MAs bordered ischemic areas; fewer than 10% localized inside these regions. As DMI area increased, so did associated MAs (SCP: r = 0.695, P < 0.001; DCP: r = 0.726, P < 0.001). Density of MAs surrounding FAZ (7.7 ± 6.0 MAs/mm2) was similar to other DMI areas (SCP: 7.0 ± 4.0 MAs/mm2, P = 0.478; DCP: 9.2 ± 10.9 MAs/mm2, P = 0.394). Conclusion MAs identified in FFA strongly associate with, and border areas of, DMI delineated by OCTA. Although more MAs are localized to SCP ischemia, the concentration of MAs associated with DCP ischemia is greater. By contrast, few MAs are present inside low-flow regions, likely because capillary loss is associated with their regression.
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Affiliation(s)
- Ahmed A Abdel-Kader
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - David J Ramsey
- Division of Ophthalmology, Department of Surgery, Lahey Hospital and Medical Center, Burlington, MA, USA
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA, USA
| | - Wael A Yussuf
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Ahmed A Mohalhal
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Mohamed A Eldaly
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Ayman G Elnahry
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Kwan JT, Ramsey DJ. Multimodal image alignment aids in the evaluation and monitoring of sector retinitis pigmentosa. Ophthalmic Genet 2023; 44:93-102. [PMID: 35769018 DOI: 10.1080/13816810.2022.2092755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To present a semi-automated method of image alignment to aid in monitoring the progression of inherited retinal degenerations (IRDs). RESULTS A 22-year-old woman presented with nyctalopia and a family history of retinitis pigmentosa (RP), but with no prior genetic testing. Fundus examination showed a sectoral retinal degeneration involving the inferior and nasal retina with rare, pigmented deposits. Goldmann kinetic perimetry demonstrated corresponding superotemporal visual field defects. The best-corrected visual acuity was 20/20 in both eyes. Multimodal imaging delineated geographically restricted peripheral retinal degeneration extending to the inferior edge of the macula. Central visual function remained intact with normal multifocal electroretinography findings. Optical coherence tomography (OCT) through the leading edge of the retinal degeneration confirmed loss of the photoreceptor layer and associated retinal pigment epithelium. In the region of retinal degeneration, loss of vascular flow density was noted on optical coherence tomography angiography (OCTA). Genetic testing identified a pathologic sequence variant in RHO (c.68C>A, p.Pro23His), confirming autosomal dominant sector retinitis pigmentosa (SRP). Image alignment allowed for precise measurement of the progression of SRP over a period of 18 months. CONCLUSION SRP is a rare subtype of RP characterized by focal, typically inferior and nasal, retinal degeneration of the peripheral retina. Although the onset and extent of peripheral retinal degeneration varies, compared with RP, SRP typically progresses more slowly to involve the macula. In this report, we highlight the utility of image registration and alignment to aid in monitoring disease progression in IRDs by means of multimodal imaging.
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Affiliation(s)
- James T Kwan
- Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts, USA.,Department of Surgery, Division of Ophthalmology, Lahey Hospital & Medical Center, Burlington, Massachusetts, USA
| | - David J Ramsey
- Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts, USA.,Department of Surgery, Division of Ophthalmology, Lahey Hospital & Medical Center, Burlington, Massachusetts, USA
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Elnahry AG, Hassan LM, Abdelrahman W, Abd Elmohsen MN. Optical coherence tomography angiography (OCTA) findings in juvenile idiopathic arthritis. THE EGYPTIAN RHEUMATOLOGIST 2023. [DOI: 10.1016/j.ejr.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Tsai WS, Thottarath S, Gurudas S, Sen P, Pearce E, Giani A, Chong V, Cheung CMG, Sivaprasad S. Correlation of Optical Coherence Tomography Angiography Characteristics with Visual Function to Define Vision-Threatening Diabetic Macular Ischemia. Diagnostics (Basel) 2022; 12:diagnostics12051050. [PMID: 35626206 PMCID: PMC9139901 DOI: 10.3390/diagnostics12051050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/15/2022] [Accepted: 04/20/2022] [Indexed: 12/10/2022] Open
Abstract
The thresholds of macular microvasculature parameters associated with mild visual impairment in diabetic macular ischemia (DMI) patients are unclear. Therefore, this prospective observational study is aimed at demonstrating the optical coherence tomography angiography parameters that best correlate with mild visual impairment (<70 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, Snellen equivalent 20/40) in DMI. The study was completed at the Moorfields Eye Hospital from December 2019 to August 2021. A total of 123 eyes of 87 patients with stable-treated proliferative diabetic retinopathy following panretinal photocoagulation were recruited. DMI was defined as an irregular foveal avascular zone (FAZ) area ≥ 0.5 mm2 or a smaller FAZ area with parafoveal capillary dropout in at least one quadrant. The analysis showed that the whole image deep vascular complex vessel density (DVC VD) in the 3 × 3 mm area had the best discriminatory ability to identify participants with mild visual impairment at 41.9% (area under the curve = 0.77, sensitivity 94%, specificity 54%, likelihood ratio [LR] = 2.04), and the FAZ area had the greatest post-test LR = 4.21 at 0.64 mm2. The 3 × 3 mm whole image DVC VD and FAZ area cutoffs are useful for screening vision-threatening DMI, but DVC VD has low specificity.
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Affiliation(s)
- Wei-Shan Tsai
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK; (W.-S.T.); (S.T.)
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK; (S.G.); (P.S.); (V.C.)
| | - Sridevi Thottarath
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK; (W.-S.T.); (S.T.)
| | - Sarega Gurudas
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK; (S.G.); (P.S.); (V.C.)
| | - Piyali Sen
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK; (S.G.); (P.S.); (V.C.)
| | - Elizabeth Pearce
- Boehringer Ingelheim, Binger Street 173, 55218 Ingelheim am Rhein, Germany; (E.P.); (A.G.)
| | - Andrea Giani
- Boehringer Ingelheim, Binger Street 173, 55218 Ingelheim am Rhein, Germany; (E.P.); (A.G.)
| | - Victor Chong
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK; (S.G.); (P.S.); (V.C.)
| | | | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK; (W.-S.T.); (S.T.)
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK; (S.G.); (P.S.); (V.C.)
- Correspondence: ; Tel.: +44-7817-886759
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Meng Y, Lan H, Hu Y, Chen Z, Ouyang P, Luo J. Application of Improved U-Net Convolutional Neural Network for Automatic Quantification of the Foveal Avascular Zone in Diabetic Macular Ischemia. J Diabetes Res 2022; 2022:4612554. [PMID: 35257013 PMCID: PMC8898103 DOI: 10.1155/2022/4612554] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/02/2021] [Accepted: 02/11/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES The foveal avascular zone (FAZ) is a biomarker for quantifying diabetic macular ischemia (DMI), to automate the identification and quantification of the FAZ in DMI, using an improved U-Net convolutional neural network (CNN) and to establish a CNN model based on optical coherence tomography angiography (OCTA) images for the same purpose. METHODS The FAZ boundaries on the full-thickness retina of 6 × 6 mm en face OCTA images of DMI and normal eyes were manually marked. Seventy percent of OCTA images were used as the training set, and ten percent of these images were used as the validation set to train the improved U-Net CNN with two attention modules. Finally, twenty percent of the OCTA images were used as the test set to evaluate the accuracy of this model relative to that of the baseline U-Net model. This model was then applied to the public data set sFAZ to compare its effectiveness with existing models at identifying and quantifying the FAZ area. RESULTS This study included 110 OCTA images. The Dice score of the FAZ area predicted by the proposed method was 0.949, the Jaccard index was 0.912, and the area correlation coefficient was 0.996. The corresponding values for the baseline U-Net were 0.940, 0.898, and 0.995, respectively, and those based on the description data set sFAZ were 0.983, 0.968, and 0.950, respectively, which were better than those previously reported based on this data set. CONCLUSIONS The improved U-Net CNN was more accurate at automatically measuring the FAZ area on the OCTA images than the traditional CNN. The present model may measure the DMI index more accurately, thereby assisting in the diagnosis and prognosis of retinal vascular diseases such as diabetic retinopathy.
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Affiliation(s)
- Yongan Meng
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Hailei Lan
- School of Computer Science and Engineering, Central South University, Changsha 410083, China
| | - Yuqian Hu
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Zailiang Chen
- School of Computer Science and Engineering, Central South University, Changsha 410083, China
| | - Pingbo Ouyang
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Jing Luo
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
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Elnahry AG, Noureldine AM, Abdel-Kader AA, Sorour OA, Ramsey DJ. Optical Coherence Tomography Angiography Biomarkers Predict Anatomical Response to Bevacizumab in Diabetic Macular Edema. Diabetes Metab Syndr Obes 2022; 15:395-405. [PMID: 35177916 PMCID: PMC8843414 DOI: 10.2147/dmso.s351618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/25/2022] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To identify biomarkers that may predict an early anatomical response to the treatment of diabetic macular edema (DME) with intravitreal bevacizumab (IVB) by means of optical coherence tomography angiography (OCTA). METHODS This study is a retrospective study of treatment-naïve patients with DME who underwent 6 × 6 mm OCTA imaging of the macula at baseline and after three monthly IVB injections. Thirty-six eyes of 23 patients were included. Eyes that demonstrated evidence of an early anatomical response, consisting of a >10% decrease in central macular thickness (CMT) (n = 18), were compared with those eyes that failed to show such an improvement (n = 18). RESULTS At baseline, early-response eyes had worse starting best-corrected visual acuity (BCVA, LogMAR 0.84 ± 0.41 versus LogMAR 0.51 ± 0.15, p = 0.004) and a larger CMT (490 ± 135 µm versus 356 ± 33 µm, p = 0.001), but smaller foveal avascular zones (FAZ) (0.309 ± 0.098mm versus 0.413 ± 0.095 mm, p = 0.003) compared with eyes that proved refractory to three monthly injections of IVB. The vascular density (VD) in both the foveal superficial and deep capillary plexuses was significantly greater in eyes that showed an early-treatment response compared with eyes that were non-responders (24.86 ± 6.90% versus 19.98 ± 7.13%, p = 0.045 and 32.30 ± 4.88% versus 26.95 ± 7.25%, p = 0.028, respectively). Early-treatment response to IVB was predicted by starting CMT (r 2= 0.266, p = 0.001), FAZ size (r 2= 0.234, p = 0.003), and VD in the superficial parafovea (r 2= 0.217, p = 0.004) and deep fovea (r 2= 0.157, p = 0.037). CONCLUSION Projection-resolved OCTA may be useful in predicting an early anatomical response of DME to treatment with IVB.
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Affiliation(s)
- Ayman G Elnahry
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
- Correspondence: Ayman G Elnahry, Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, 11956, Egypt, Tel +20 1224927604, Fax +20 223682030, Email
| | - Alia M Noureldine
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Ahmed A Abdel-Kader
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Osama A Sorour
- Department of Ophthalmology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - David J Ramsey
- Division of Ophthalmology, Lahey Hospital & Medical Center, Tufts University School of Medicine, Boston, MA, USA
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Elnahry AG, Elnahry GA. Optical Coherence Tomography Angiography of Macular Perfusion Changes after Anti-VEGF Therapy for Diabetic Macular Edema: A Systematic Review. J Diabetes Res 2021; 2021:6634637. [PMID: 34124270 PMCID: PMC8169275 DOI: 10.1155/2021/6634637] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/14/2021] [Accepted: 04/20/2021] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Diabetic macular edema (DME) is a major cause of vision loss in diabetics that is currently mainly treated by antivascular endothelial growth factor (VEGF) agents. The effect of these agents on macular perfusion (MP) is a current concern. Optical coherence tomography angiography (OCTA) is an imaging modality that allows noninvasive high-resolution retinal microvasculature imaging. Several recent studies evaluated the effect of anti-VEGF agents on the MP of DME patients using OCTA. Our aim is to provide a systematic review of these studies. METHODS Multiple databases were searched including PubMed, Ovid Medline, EMBASE, and Google Scholar for relevant studies published between January 2016 and November 2020 which were included in this review. Studies were compared regarding their design, the number of included patients, the machine and scanning protocol used, the inclusion and exclusion criteria, the number of injections given, the type of anti-VEGF agent used, the outcome measures assessed, and the effect of injections on different MP parameters. RESULTS A total of 16 studies were included. The studies assessed various OCTA parameters that define MP including the foveal avascular zone area and superficial and deep vascular density and yielded conflicting results. Seven studies showed stable or improved MP following treatment, while 7 studies showed worsening MP following treatment, and 2 studies showed inconclusive results. This could have been due to differences in study design, inclusion criteria, type of anti-VEGF agents used, treatment duration, and methods of image analysis and vascular density quantification. All identified studies were noncomparative case series, and 14 of them (87.5%) used the RTVue XR Avanti OCTA machine. Only one study compared OCTA to fluorescein angiography findings. CONCLUSION Analysis of MP changes following VEGF inhibition for DME could benefit from a unified scanning protocol and analysis approach that uses similar study designs to eliminate potential sources of bias. This may provide more definitive conclusions regarding the effect of treatment on MP.
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Affiliation(s)
- Ayman G. Elnahry
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
- Elnahry Eye Clinics, Giza, Egypt
| | - Gehad A. Elnahry
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
- Elnahry Eye Clinics, Giza, Egypt
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Elnahry AG, Ramsey DJ. Automated Image Alignment for Comparing Microvascular Changes Detected by Fluorescein Angiography and Optical Coherence Tomography Angiography in Diabetic Retinopathy. Semin Ophthalmol 2021; 36:757-764. [PMID: 33784213 DOI: 10.1080/08820538.2021.1901122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE To quantitatively compare microvascular features in the macula of patients with diabetic retinopathy (DR) using fluorescein angiography (FA) and optical coherence tomography angiography (OCTA). METHODS Patients with DR were recruited from the Cairo University Hospital. FA was performed using a Topcon TRC-50DX or Heidelberg Spectralis HRA+OCT. OCTA was performed using an Optovue RTVue-XR Avanti. FA images were cropped and aligned to the corresponding OCTA images using i2k Align Retina software. The foveal avascular zone (FAZ), area of ischemia, and microaneurysms (MAs) were manually quantified using ImageJ. The fractal dimension (FD) was calculated from each skeletonized image using the FracLac plugin of ImageJ after retinal vascular segmentation. RESULTS Twenty-four eyes of 17 patients were evaluated, but only 18 eyes were successfully aligned. There was no difference in FAZ area measured for FA and OCTA images. Compared with OCTA images, FD was significantly less for FA images (1.66 ± 0.048 versus 1.72 ± 0.023, p < .001). Significantly more MAs were identified on FA images (102 ± 27.5) compared with OCTA (47.5 ± 11.7, p < .0001). The number of MAs on FA correlated with decreasing best corrected visual acuity (r2 = 0.315, p = .015) and increasing central macular thickness (r2 = 0.492, p = .001). No such associations were found with MAs detected on OCTA. Nevertheless, the area of ischemia in the FA images (8.5 ± 4.1%) was significantly smaller compared with the area measured in both the superficial (30.7 ± 9.5%) and deep capillary plexus (21.6 ± 10.9%) of the OCTA (p < .001). Interestingly, number of MAs in the FA images correlated with increasing area of ischemia in the FA (r2 = 0.568, p < .001) but only the superficial segment of the depth-resolved OCTA scans (r2 = 0.539, p < .001). CONCLUSIONS OCTA is a non-invasive tool capable of resolving the retinal vasculature in greater detail when compared with FA but detects significantly fewer MAs. Automatic alignment facilitates quantitative comparison of the microvascular features in DR.
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Affiliation(s)
- Ayman G Elnahry
- Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - David J Ramsey
- Department of Ophthalmology, Lahey Hospital & Medical Center, Beth Israel Lahey Health, Peabody, MA, USA.,Department of Ophthalmology, Tufts University School of Medicine, Boston, MA, USA
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