Evaluation of Radiation Maculopathy after Treatment of Choroidal Melanoma with Ruthenium-106 using Optical Coherence Tomography Angiography
Hamid Riazi Esfahani1 *, Fariba Ghassemi1 , Ali Torkashvand1 , Baback Masoomian1 , Mohammad Zarei1 , Elias Khalili Pour1 , Kaveh Fadakar1 , Hamid Abrishami Moghaddam2 , Leila Ekradi 2 , Tahereh Mahmoudi 3
- Retina service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
- Machine Vision and Medical Image Processing (MVMIP) Lab. Faculty of Electrical Engineering.K.N., Toosi University of Technology, Tehran, Iran.
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences and Research Center for Science and Technology in Medicine, Tehran, Iran.
Abstract: To assess the impact of brachytherapy on macular microvasculature utilizing optical coherence tomography angiography (OCTA) in treated choroidal melanoma
Methods: In this retrospective observational case series, we reviewed the recorded data of the patients with choroidal melanoma treated with rheuthenium-106 (106Ru) plaque radiotherapy with follow-up period of more than 6 months. All images were exported to Matlab software R2019a (Mathworks, Inc., Natick, MA) for further image processing and analysis. Automatically measured OCTA retinal parameters were analyzed after image processing. The non-irradiated fellow eye is considered as the control.
Results: Thirty-one eyes of 31 patients with the mean age of 51.1 years were recruited. Six eyes had no radiation maculopathy (RM). From 25 eyes with RM, nine eyes (36%) revealed a burnout macular microvasculature with imperceptible vascular details. Foveal and optic disc radiation dose had the highest value to predict the burnout pattern (ROC, AUC: 0.763, 0.727). Superficial and deep foveal avascular zone (FAZ) were larger in irradiated eyes in comparison to healthy eyes (1629 µm2 vs. 428 µm2, P =0.005; 1837 µm2 vs 268 µm2, P =0.021; respectively). Foveal and parafoveal vascular area density (VAD) and vascular skeleton density (VSD) in both superficial and deep capillary plexus (SCP and DCP) were decreased in all irradiated eyes in comparison with control eyes (P< 0.001). Compared with fellow healthy eyes, irradiated eyes without RM had significantly lower VAD and VSD at foveal and parafoveal DCP (all P<0.02). However, these differences at SCP were not statistically significant.
Conclusion: The OCTA is a valuable tool for evaluating RM. Initial subclinical microvascular insult after 106Ru brachytherapy is more likely to occur in DCP. The deep FAZ area was identified as a more critical biomarker of BCVA than superficial FAZ in these patients.
