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Karperien AL, Jelinek HF. Box-Counting Fractal Analysis: A Primer for the Clinician. ADVANCES IN NEUROBIOLOGY 2024; 36:15-55. [PMID: 38468026 DOI: 10.1007/978-3-031-47606-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
This chapter lays out the elementary principles of fractal geometry underpinning much of the rest of this book. It assumes a minimal mathematical background, defines the key principles and terms in context, and outlines the basics of a fractal analysis method known as box counting and how it is used to perform fractal, lacunarity, and multifractal analyses. As a standalone reference, this chapter grounds the reader to be able to understand, evaluate, and apply essential methods to appreciate and heal the exquisitely detailed fractal geometry of the brain.
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Affiliation(s)
| | - Herbert F Jelinek
- Department of Medical Sciences and Biotechnology Center, Khalifa University, Abu Dhabi, UAE
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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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Xiao H, Tang J, Zhang F, Liu L, Zhou J, Chen M, Li M, Wu X, Nie Y, Duan J. Global trends and performances in diabetic retinopathy studies: A bibliometric analysis. Front Public Health 2023; 11:1128008. [PMID: 37124794 PMCID: PMC10136779 DOI: 10.3389/fpubh.2023.1128008] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/09/2023] [Indexed: 05/02/2023] Open
Abstract
Objective The objective of this study is to conduct a comprehensive bibliometric analysis to identify and evaluate global trends in diabetic retinopathy (DR) research and visualize the focus and frontiers of this field. Methods Diabetic retinopathy-related publications from the establishment of the Web of Science (WOS) through 1 November 2022 were retrieved for qualitative and quantitative analyses. This study analyzed annual publication counts, prolific countries, institutions, journals, and the top 10 most cited literature. The findings were presented through descriptive statistics. VOSviewer 1.6.17 was used to exhibit keywords with high frequency and national cooperation networks, while CiteSpace 5.5.R2 displayed the timeline and burst keywords for each term. Results A total of 10,709 references were analyzed, and the number of publications continuously increased over the investigated period. America had the highest h-index and citation frequency, contributing to the most influence. China was the most prolific country, producing 3,168 articles. The University of London had the highest productivity. The top three productive journals were from America, and Investigative Ophthalmology Visual Science had the highest number of publications. The article from Gulshan et al. (2016; co-citation counts, 2,897) served as the representative and symbolic reference. The main research topics in this area were incidence, pathogenesis, treatment, and artificial intelligence (AI). Deep learning, models, biomarkers, and optical coherence tomography angiography (OCTA) of DR were frontier hotspots. Conclusion Bibliometric analysis in this study provided valuable insights into global trends in DR research frontiers. Four key study directions and three research frontiers were extracted from the extensive DR-related literature. As the incidence of DR continues to increase, DR prevention and treatment have become a pressing public health concern and a significant area of research interest. In addition, the development of AI technologies and telemedicine has emerged as promising research frontiers for balancing the number of doctors and patients.
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Affiliation(s)
- Huan Xiao
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jinfan Tang
- School of Acupuncture-Moxibustion and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Feng Zhang
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Luping Liu
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jing Zhou
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Meiqi Chen
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Mengyue Li
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaoxiao Wu
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yingying Nie
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Junguo Duan
- School of Ophthalmology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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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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Gamal El-Deen A, Abd El-Hamid S, Farrag E. Serum brain-derived neurotrophic factor and macular perfusion in type 2 diabetes mellitus using optical coherence tomography angiography. Taiwan J Ophthalmol 2023; 0:0. [DOI: 10.4103/tjo.tjo-d-22-00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
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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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Ramsey DJ, Kwan JT, Sharma A. Keeping an eye on the diabetic foot: The connection between diabetic eye disease and wound healing in the lower extremity. World J Diabetes 2022; 13:1035-1048. [PMID: 36578874 PMCID: PMC9791566 DOI: 10.4239/wjd.v13.i12.1035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 10/27/2022] [Accepted: 11/18/2022] [Indexed: 12/15/2022] Open
Abstract
Diabetic eye disease is strongly associated with the development of diabetic foot ulcers (DFUs). DFUs are a common and significant complication of diabetes mellitus (DM) that arise from a combination of micro- and macrovascular compromise. Hyperglycemia and associated metabolic dysfunction in DM lead to impaired wound healing, immune dysregulation, peripheral vascular disease, and diabetic neuropathy that predisposes the lower extremities to repetitive injury and progressive tissue damage that may ultimately necessitate amputation. Diabetic retinopathy (DR) is caused by cumulative damage to the retinal mic-rovasculature from hyperglycemia and other diabetes-associated factors. The severity of DR is closely associated with the development of DFUs and the need for lower extremity revascularization procedures and/or amputation. Like the lower extremity, the eye may also suffer end-organ damage from macrovascular compromise in the form of cranial neuropathies that impair its motility, cause optic neuropathy, or result in partial or complete blindness. Additionally, poor perfusion of the eye can cause ischemic retinopathy leading to the development of proliferative diabetic retinopathy or neovascular glaucoma, both serious, vision-threatening conditions. Finally, diabetic corneal ulcers and DFUs share many aspects of impaired wound healing resulting from neurovascular, sensory, and immunologic compromise. Notably, alterations in serum biomarkers, such as hemoglobin A1c, ceruloplasmin, creatinine, low-density lipoprotein, and high-density lipoprotein, are associated with both DR and DFUs. Monitoring these parameters can aid in prognosticating long-term outcomes and shed light on shared pathogenic mechanisms that lead to end-organ damage. The frequent co-occurrence of diabetic eye and foot problems mandate that patients affected by either condition undergo reciprocal comprehensive eye and foot evaluations in addition to optimizing diabetes management.
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Affiliation(s)
- David J Ramsey
- Department of Ophthalmology, Lahey Hospital and Medical Center, Burlington, MA 01805, United States
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - James T Kwan
- Department of Ophthalmology, Lahey Hospital and Medical Center, Burlington, MA 01805, United States
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Arjun Sharma
- Department of Ophthalmology, Lahey Hospital and Medical Center, Burlington, MA 01805, United States
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111, United States
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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, 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: 10] [Impact Index Per Article: 3.3] [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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