ABSTRACT
BACKGROUND: To evaluate the optimal compression level of retinal color digital video recordings, a novel video-based imaging technology, in screening for diabetic retinopathy (DR). DESIGN: Evaluation of a diagnostic technique. METHODS: A total of 36 retinal videos, captured using EyeScan (Ophthalmic Imaging System), were compressed from original uncompressed file size of 1 GB (gigabyte) to four different compression levels-100 MB (megabyte) (Group 1); 30 MB (Group 2); 20 MB (Group 3); and 5 MB (Group 4). The videos were subsequently interpreted by an ophthalmologist and a resident using the International Clinical Diabetic Retinopathy Severity Scales. MAIN OUTCOME MEASURES: The sensitivity, specificity and κ coefficient for DR grading detected by were calculated for each compression level (Groups 1-4), with reference to the original uncompressed retinal videos. RESULTS: Groups 1, 2, and 3 graded by both readers had sensitivity and specificity >90% in detecting DR, whereas for group 4, the sensitivity and specificity were 70.6% and 94.7% for ophthalmologist and 80.0% and 72.2% medical officer, respectively. The κ correlation in detecting DR for groups 1, 2, and 3 were >0.95, whereas for Group 4, the κ was 0.76 and 0.66 for ophthalmologist and medical officer, respectively. CONCLUSION: Retinal video recording is a novel and effective DR screening technique with high sensitivity, specificity and κ correlation. With its compressibility, this is a potential effective technique that can be widely implemented in a routine, mobile, and tele-ophthalmology setting for DR screening services.
Subject(s)
Diabetic Retinopathy/diagnosis , Diagnostic Techniques, Ophthalmological/standards , Image Processing, Computer-Assisted , Video Recording/methods , Electronic Data Processing/methods , Humans , Mass Screening/methods , Sensitivity and Specificity , Video Recording/standardsABSTRACT
The earliest detectable change in Alzheimer's disease (AD) is the buildup of amyloid plaque in the brain. Early detection of AD, prior to irreversible neurological damage, is important for the efficacy of current interventions as well as for the development of new treatments. Although PiB-PET imaging and CSF amyloid are the gold standards for early AD diagnosis, there are practical limitations for population screening. AD-related pathology occurs primarily in the brain, but some of the hallmarks of the disease have also been shown to occur in other tissues, including the retina, which is more accessible for imaging. Retinal vascular changes and degeneration have previously been reported in AD using optical coherence tomography and laser Doppler techniques. This report presents results from analysis of retinal photographs from AD and healthy control participants from the Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing. This is the first study to investigate retinal blood vessel changes with respect to amyloid plaque burden in the brain. We demonstrate relationships between retinal vascular parameters, neocortical brain amyloid plaque burden and AD. A number of RVPs were found to be different in AD. Two of these RVPs, venular branching asymmetry factor and arteriolar length-to-diameter ratio, were also higher in healthy individuals with high plaque burden (P = 0.01 and P = 0.02 respectively, after false discovery rate adjustment). Retinal photographic analysis shows potential as an adjunct for early detection of AD or monitoring of AD-progression or response to treatments.
Subject(s)
Alzheimer Disease/complications , Alzheimer Disease/diagnosis , Retinal Diseases/complications , Retinal Diseases/diagnosis , Aged , Analysis of Variance , Australia , Biomarkers , Brain/diagnostic imaging , Cohort Studies , Disease Progression , Early Diagnosis , Female , Humans , Male , Photography/methods , Plaque, Amyloid/diagnostic imaging , Positron-Emission Tomography/methods , Reproducibility of Results , Retinal Artery , Retinal VeinABSTRACT
PURPOSE: To evaluate the accuracy of different viewing monitors for image reading and grading of diabetic retinopathy (DR). DESIGN: Single-centre, experimental case series-evaluation of reading devices for DR screening. METHOD: A total of 100 sets of three-field (optic disc, macula, and temporal views) colour retinal still images (50 normal and 50 with DR) captured by FF 450 plus (Carl Zeiss) were interpreted on 27-inch iMac, 15-inch MacBook Pro, and 9.7-inch iPad. All images were interpreted by a retinal specialist and a medical officer. We calculated the sensitivity and specificity of 15-inch MacBook Pro and 9.7-inch iPad in detection of DR signs and grades with reference to the reading outcomes obtained using a 27-inch iMac reading monitor. RESULTS: In detection of any grade of DR, the 15-inch MacBook Pro had sensitivity and specificity of 96% (95% confidence interval (CI): 85.1-99.3) and 96% (95% CI: 85.1-99.3), respectively, for retinal specialist and 91.5% (95% CI: 78.7-97.2) and 94.3% (95% CI: 83.3-98.5), respectively, for medical officer, whereas for 9.7-inch iPad, they were 91.8% (95% CI: 79.5-97.4) and 94.1% (95% CI: 82.8-98.5), respectively, for retinal specialist and 91.3% (95% CI: 78.3-97.1) and 92.6% (95% CI: 81.3-97.6), respectively, for medical officer. CONCLUSION: The 15-inch MacBook Pro and 9.7-inch iPad had excellent sensitivity and specificity in detecting DR and hence, both screen sizes can be utilized to effectively interpret colour retinal still images for DR remotely in a routine, mobile or tele-ophthalmology setting. Future studies could explore the use of more economical devices with smaller viewing resolutions to reduce cost implementation of DR screening services.
