Yifan Lu1,2, Jay C Wang1,2,3, Ying Cui1,4, Ying Zhu1,5, Rebecca Zeng1, Edward S Lu1,2, Raviv Katz1, Deeba Husain2,3, Demetrios G Vavvas2,3, Leo A Kim2,3, Joan W Miller2,3, John B Miller6,7,8,9. 1. Harvard Retinal Imaging Lab, Massachusetts Eye and Ear, Boston, MA, USA. 2. Department of Ophthalmology, Harvard Medical School, Boston, MA, USA. 3. Retina Service, Massachusetts Eye and Ear, Boston, MA, USA. 4. Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China. 5. Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan, China. 6. Harvard Retinal Imaging Lab, Massachusetts Eye and Ear, Boston, MA, USA. john_miller@meei.harvard.edu. 7. Department of Ophthalmology, Harvard Medical School, Boston, MA, USA. john_miller@meei.harvard.edu. 8. Retina Service, Massachusetts Eye and Ear, Boston, MA, USA. john_miller@meei.harvard.edu. 9. Retina Service, Mass. Eye and Ear Infirmary, Harvard Medical School, 243 Charles St, Boston, MA, 02114, USA. john_miller@meei.harvard.edu.
Abstract
PURPOSE: Optical coherence tomography angiography (OCT-A) is a novel imaging modality for the diagnosis of chorioretinal diseases. A number of FDA-approved OCT-A devices are currently commercially available, each with unique algorithms and scanning protocols. Although several published studies have compared different combinations of OCT-A machines, there is a lack of agreement on the consistency of measurements across OCT-A devices. Therefore, we conducted a prospective quantitative comparison of four available OCT-A platforms. METHODS: Subjects were scanned on four devices: Optovue RTVue-XR, Heidelberg Spectralis OCT2 module, Zeiss Plex Elite 9000 Swept-Source OCT, and Topcon DRI-OCT Triton Swept-Source OCT. 3 mm × 3 mm images were utilized for analysis. Foveal avascular zone (FAZ) area was separately and independently measured by two investigators. Fractal dimension (FD), superficial capillary plexus (SCP), and deep capillary plexus (DCP) vessel densities (VD) were calculated from binarized images using the Fiji image processing software. SCP and DCP VD were further calculated after images were skeletonized. Repeated measures ANOVA, post hoc tests, and interclass correlation coefficient (ICC) were performed for statistical analysis. RESULTS: Sixteen healthy eyes from sixteen patients were scanned on the four devices. Images of five eyes from the Triton device were excluded due to poor image quality; thus, the authors performed two sets comparisons, one with and one without the Triton machine. FAZ area showed no significant difference across devices with an ICC of > 95%. However, there were statistically significant differences for SCP and DCP VD both before and after skeletonization (p < 0.05). Fractal analysis revealed no significant difference of FD at the SCP; however, a statistically significant difference was found for FD at the DCP layer (p < 0.05). CONCLUSIONS: The results showed that FAZ measurements were consistent across all four devices, while significant differences in VD and FD measurements existed. Therefore, we suggest that for both clinical follow-up and research studies, FAZ area is a useful parameter for OCT-A image analysis when measurements are made on different machines, while VD and FD show significant variability when measured across devices.
PURPOSE: Optical coherence tomography angiography (OCT-A) is a novel imaging modality for the diagnosis of chorioretinal diseases. A number of FDA-approved OCT-A devices are currently commercially available, each with unique algorithms and scanning protocols. Although several published studies have compared different combinations of OCT-A machines, there is a lack of agreement on the consistency of measurements across OCT-A devices. Therefore, we conducted a prospective quantitative comparison of four available OCT-A platforms. METHODS: Subjects were scanned on four devices: Optovue RTVue-XR, Heidelberg Spectralis OCT2 module, Zeiss Plex Elite 9000 Swept-Source OCT, and Topcon DRI-OCT Triton Swept-Source OCT. 3 mm × 3 mm images were utilized for analysis. Foveal avascular zone (FAZ) area was separately and independently measured by two investigators. Fractal dimension (FD), superficial capillary plexus (SCP), and deep capillary plexus (DCP) vessel densities (VD) were calculated from binarized images using the Fiji image processing software. SCP and DCP VD were further calculated after images were skeletonized. Repeated measures ANOVA, post hoc tests, and interclass correlation coefficient (ICC) were performed for statistical analysis. RESULTS: Sixteen healthy eyes from sixteen patients were scanned on the four devices. Images of five eyes from the Triton device were excluded due to poor image quality; thus, the authors performed two sets comparisons, one with and one without the Triton machine. FAZ area showed no significant difference across devices with an ICC of > 95%. However, there were statistically significant differences for SCP and DCP VD both before and after skeletonization (p < 0.05). Fractal analysis revealed no significant difference of FD at the SCP; however, a statistically significant difference was found for FD at the DCP layer (p < 0.05). CONCLUSIONS: The results showed that FAZ measurements were consistent across all four devices, while significant differences in VD and FD measurements existed. Therefore, we suggest that for both clinical follow-up and research studies, FAZ area is a useful parameter for OCT-A image analysis when measurements are made on different machines, while VD and FD show significant variability when measured across devices.
Authors: Marion R Munk; Helena Giannakaki-Zimmermann; Lieselotte Berger; Wolfgang Huf; Andreas Ebneter; Sebastian Wolf; Martin S Zinkernagel Journal: PLoS One Date: 2017-05-10 Impact factor: 3.240