Purpose
Polypoidal choroidal vasculopathy (PCV) and age-related macular degeneration (AMD) share many common clinical features, but the diseases have different clinical courses and visual prognoses. It is believed that PCV and AMD are indistinguishable using flurorescein angiography (FA) alone. However, indocyanine green angiography (ICGA) may be contraindicated in some patients. In such cases, ophthalmologists may need to make a diagnosis based on FA or clinical features. We aimed to describe the distinguishing FA features of PCV compared to neovascular AMD and determine the predictive value of these features in the diagnosis of PCV.
Methods
The EVEREST study was a prospective, multi-center study of 78 patients - 60 with PCV and 18 with neovascular AMD. All patients underwent dilated color fundus photography and confocal scanning laser ophthalmoscopy FA and ICGA using standardized imaging protocols. The angiographic features were independently graded by masked graders (Fellowship-trained ophthalmologists) from an image Reading Center using standardized diagnostic algorithms. The diagnosis of PCV or AMD was confirmed using ICGA. Predictive features for PCV on FA were analyzed using multiple logistic regression.
Results
Patients with PCV had predominantly occult choroidal neovascularisation (CNV) on FA (90.0% vs. 73.3% of AMD patients), while classic CNV was less frequent (5.0% vs. 22.2%). The mean area of classic CNV was significantly smaller in patients with PCV (0.09 vs. 0.65 mm2, p=0.005). The presence of a nodular hyperfluorescent area on stereoscopic FA, which corresponded to the clinical location of the polyp, was highly predictive of PCV (80.0% vs. 16.7%, p<0.001). Blockage of fluorescence on FA occurred more frequently in PCV (61.7% vs. 16.7%, p=0.001). Using logistic regression analysis, the most predictive features for PCV were nodular hyperfluorescence (p=0.001) and blocked fluorescence (p=0.018).
Conclusions
This study has identified several distinguishing features on FA which are highly predictive of PCV compared to AMD. In situations where confirmatory investigations such as ICGA are unvailable or contra-indicated, it may be possible to identify patients who are likely to have PCV using FA characteristics alone. Ophthalmologists who detect such features on FA should have a high index of suspicion for PCV.
Keywords: 412 age-related macular degeneration •
550 imaging/image analysis: clinical •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)