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H. Ishikawa, G. Wollstein, M. Aoyama, D. Stein, S. Beaton, J.G. Fujimoto, J.S. Schuman; Stratus OCT Image Quality Assessment . Invest. Ophthalmol. Vis. Sci. 2004;45(13):3317.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To compare the newly introduced image quality parameter for optical coherence tomography (OCT; Stratus OCT, Carl Zeiss Meditec, Inc., Dublin, CA) images with our quality index presented at the ARVO 2003. Methods: Stratus OCT images (linear macular scan, peripapillary circular scan, and optic nerve head scan) were analyzed using Stratus 4.0 software, the latest OCT system software developed by Carl Zeiss Meditec, Inc.; signal to noise ratio (SNR) and image quality parameter (IQP) were calculated for each image. Raw data files of the same set of images were exported to an IBM compatible PC. Quality index (QI) was calculated based on image histogram information using a software program of our own design. To evaluate the performance of these parameters, the outcome results were compared with subjective 3–level–grading (excellent, acceptable, and poor) performed by 3 OCT experts. Results: 63 images of 21 subjects (7 each for normal, early, and advanced glaucoma) were enrolled in this study. Subjects were selected in a consecutive and retrospective fashion from our OCT imaging database. There were significant differences in SNR, IQP, and QI between excellent and poor images (p=0.04, p=0.002, and p<0.001, respectively, Wilcoxon test) and between acceptable and poor images (p=0.02, p<0.001, and p<0.001, respectively). Only QI showed a significant difference between excellent and acceptable images (p=0.001). Areas under the receiver operator characteristic (ROC) curve for discrimination of poor from excellent and acceptable images were 0.81 (SNR), 0.88 (IQP), and 1.0 (QI). Conclusions: IQP was better than SNR in terms of discrimination of poor images. QI outperformed the others in this small pilot study. A larger sample is required for further investigation.
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