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Polypoidal Choroidal Vasculopathy

Min Wang, MD, PhD; Simon S. Gao, PhD; and Yali Jia, PhD

Polypoidal choroidal vasculopathy (PCV) features a variety of clinical manifestations, such as quiescent orange subretinal nodules (polyps), serous and/or hemorrhagic detachments of the retinal pigment epithelium (RPE), serous subretinal fluid that mimics central serous chorioretinopathy, and massive submacular hemorrhage.^1–3 PCV has a higher prevalence in Asian, Black, and pigmented races.⁴ Indocyanine green angiography (ICGA) has been an essential tool for differentiating PCV from neovascular age-related macular degeneration.^5,6 ICGA findings include nodular hyper-fluorescence corresponding to orange sub-retinal nodules, hypo-fluorescent halo around the nodules, and a branching vascular network (BVN) that terminates in pulsating polyps.^7,8 Spectral domain optical coherence tomography (OCT) shows typical structural changes such as a dome-shaped pigment epithelium detachment (PED) with a hyper-reflective signal underneath the RPE and separation of the RPE and Bruch’s membrane (also referred to as the double-layered sign) corresponding to the abnormal BVN. En face OCT reveals the BVN as a hyper-reflective area around or beside the dome-shaped PED.

Although OCT provides information on abnormal structures in PCV, it does not provide blood flow information. In the last 2 years, optical coherence tomography angiography (OCTA), a new imaging technique that allows the acquisition of blood flow information in the vessels of the retina and choroid, has been made practical by the development of the split-spectrum amplitude-decorrelation algorithm developed by Jia and Huang.^9,10 This revolutionary imaging technique allows us to acquire blood flow information on PCV in a noninvasive, fast, and efficient way.

The OCTA images in this chapter were captured with the Avanti RTVue-XR spectral domain OCT system using AngioVue software (Optovue Inc, Fremont, CA). ICGA was performed with the Spectralis HRA + OCT (Heidelberg Engineering). Automated segmentation software was used to identify anatomic reference planes, with manual correction by a human grader when necessary. En face angiograms were produced by maximum flow projections in anatomic slabs. The inner retinal slab was defined as the layer lying between the inner limiting membrane and the inner plexiform layer, inclusively. The outer retinal slab was defined as the layer lying between the outer plexiform layer and Bruch’s membrane, inclusively. Manual correction was made for any error in the output of the automated segmentation. Custom adjustment of the slab depth was made to best show the pathology, and these depth settings are indicated in the figure captions. To create composite en face angiograms of the inner retina and neovascular membrane, the inner retinal angiogram (purple) was overlaid on the outer retinal angiogram (yellow) that contained the choroidal neovascularization. Composite cross-sectional B-scan images were created in a similar fashion by overlaying flow (pseudocolor) on structural OCT (grayscale) images.

A 64-year-old male Chinese patient was diagnosed with a PCV in his left eye. Color fundus photos showed polyps as orange subretinal nodules (Figure 17-1A). Early-phase ICGA revealed nodular hyper-fluorescent polyps and a BVN. ICGA showed the location of the BVN and polyp (Figure 17-1B), and OCT cross-sectional images revealed a serous PED (part of which contained the polyp) and a double-layered sign corresponding to the BVN (Figure 17-1C).

On OCTA, the polyps corresponded to the flow signal located in the upper portion of the PED just under the RPE (Figure 17-2A). The BVN was present in both the outer retinal and choroidal capillary slabs. Cross-sectional OCT showed that the BVN was located between the RPE and Bruch’s membrane (Figures 17-2A, 17-2D, and 17-2E). On en face structural OCT, the BVN was hyper-reflective in the outer retinal slab (Figure 17-2F), and the choroidal capillary slab showed an uneven OCT signal (Figure 17-2C).

In this case, the polyp flow signal was weak on OCTA, and not as obvious as the hyper-fluorescent spot on ICGA. However, the BVN was visualized more clearly on OCTA than on ICGA. Structural OCT showed typical structural change to support the diagnosis.

CASE 2

A 64-year-old male Chinese patient was diagnosed with a PCV in his right eye. Color fundus photos showed the polyps as orange subretinal nodules (Figure 17-3A). Early-phase ICGA showed the nodular hyper-fluorescent polyps and the BVN (Figure 17-3B). An OCT line scan across the hyper-fluorescent nodule showed the corresponding PED with a hyper-reflective signal under the top of a PED. Another OCT line scan across the BVN on ICGA showed the corresponding double-layered sign (Figure 17-3C).

OCTA of the outer retinal slab showed polyps as high-flow signal spots corresponding to the blood flow signal underneath the PED on the cross-sectional OCTA. The BVN was clearly apparent beside the polyps (Figure 17-4A). OCTA of the choroidal capillary slab showed the BVN more clearly than did ICGA (Figures 17-4B, 17-4D, and 17-4E). The blood flow signal of the BVN was located between the RPE and Bruch’s membrane on the cross-sectional OCTA (Figures 17-4A and 17-4D). On en face OCT, the polyps had low reflectance in the outer retinal slab. The BVN area was hyper-reflective (Figure 17-4C). En face OCT of the choroidal capillary slab showed the contour of the BVN. The large vessels in the lower left appeared bright on the dark background, but were dark on the bright background (Figure 17-4F). In this case, OCTA clearly showed both the polyps and the BVN. The BVN was visualized more clearly on OCTA than on ICGA.

CASE 3

A 60-year-old male Chinese patient was diagnosed with a PCV in his right eye. Color fundus photos showed polyps as orange subretinal nodules (Figure 17-5A), and early-phase ICGA showed the nodular hyper-fluorescent polyps (Figure 17-5B). An OCT line scan across the hyper-fluorescent nodules showed the corresponding PED. The OCT line scan across the BVN on ICGA showed the corresponding double-layered sign (Figure 17-5C).

OCTA of the outer retinal slab revealed that the polyps had high flow spots corresponding to the blood flow signal underneath the PED on the cross-sectional OCTA (Figure 17-6A). OCTA of the choroidal capillary slab showed the BVN more clearly than did ICGA (Figures 17-6B and 17-6D). The blood flow signal of the BVN was located between the RPE and Bruch’s membrane on the cross-sectional OCTA (Figures 17-6A and 17-6D). ICGA revealed several nodular hyper-fluorescent spots and the BVN (Figure 17-6B). The polyps and the BVN were hyper-reflective on the en face OCT of the outer retinal slab (Figure 17-6C). En face OCT of the choroidal capillary slab showed a high reflectance signal in the area of BVN and low reflectance signal in the areas of the PEDs (Figure 17-6E).

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