Comparison between non-visualized polyps and visualized polyps on optical coherence tomography angiography in polypoidal choroidal vasculopathy

Slab-Specific Projection-Resolved Optical Coherence Tomography Angiography for Enhancing En Face Polyp Detection in Polypoidal Choroidal Vasculopathy

Purpose

A projection-resolved optical coherence tomography angiography (PR-OCTA) algorithm with slab-specific strategy was applied in polypoidal choroidal vasculopathy (PCV) to differentiate between polyp and branching vascular network (BVN) and improve polyp detection by en face OCTA.

Methods

Twenty-nine participants diagnosed with PCV by indocyanine green angiography (ICGA) and 30 participants diagnosed with typical neovascular age-related macular degeneration (nAMD) were enrolled. Polyps were classified into three categories after using the slab-specific PR algorithm. Type 1 polyps were considered in high-elevated pigment epithelial detachment (PED) and displayed in green. Type 2 polyps were considered in low-elevated PED and encoded in yellow, similar to BVN structures. Type 3 polyps were not able to be detected on OCTA. The algorithms were tested in the nAMD group to differentiate PCV and typical nAMD.

Results

With the algorithm, type 1 polyps were readily differentiated from BVN on en face OCTA. Polyp detection rate on en face OCTA only (type 1) was 68%, which was significantly improved from 30% when the algorithm was not used (P = 0.0001). To identify type 2 polyps, a combination of en face and cross-sectional OCTA images was needed and this resulted in a 91% polyp detection rate (types 1 and 2). The absence of luminal structure on OCT at the polyp site, small polyp size, and absence of halo on ICGA appeared to influence the polyp detection rate. When applying the algorithm to the nAMD group, 83% were correctly classified as typical nAMD (absence of type 1 polyps), whereas 17% showed false detection of polyps due to flow signals at the apices of large PEDs.

Conclusions

The slab-specific PR-OCTA with different color coding provides significant improvement in detecting polyp structures on en face OCTA, leading to rapid coronal visualization and diagnosis of PCV without the risk of dye injection.

Recent Advances in Imaging Polypoidal Choroidal Vasculopathy with Swept-Source Optical Coherence Tomography Angiography

The gold standard for polypoidal choroidal vasculopathy (PCV) diagnosis is indocyanine green angiography (ICGA), but optical coherence tomography angiography (OCTA) has shown promise for PCV imaging in recent years. However, earlier generations of OCTA technology lacked the diagnostic efficacy to replace ICGA. Swept-source optical coherence tomography angiography (SS-OCTA), the latest generation of OCTA technology, has significantly improved penetrating ability, scanning speed, scanning range, and overall image quality compared with earlier generations of OCTA. SS-OCTA reveals a "tangled vasculature" pattern of polypoidal lesions (PLs), providing evidence that they are neovascular rather than aneurysmal structures. New choroidal biomarkers, such as the choriocapillaris flow void (FV), have been identified to explain the development of PCV lesions. Although no direct comparison between SS-OCTA and previous OCTA generations in terms of diagnostic capability has been performed, SS-OCTA has shown several advantages in differential diagnosis and monitoring early reactivation for PCV. These improvements make SS-OCTA a valuable tool for PCV diagnosis and follow-up, and it may become more important for this disease in the future. This review summarized recent advances in PCV morphology and structure, as well as the possible pathogenesis based on SS-OCTA findings. The value of SS-OCTA for PCV management is discussed, along with remaining issues, to provide an updated understanding of PCV and OCTA-guided management.

Polypoidal Choroidal Vasculopathy: Updates on Risk Factors, Diagnosis, and Treatments

There have been recent advances in basic research and clinical studies in polypoidal choroidal vasculopathy (PCV). A recent, large-scale, population-based study found systemic factors, such as male gender and smoking, were associated with PCV, and a recent systematic review reported plasma C-reactive protein, a systemic biomarker, was associated with PCV. Growing evidence points to an association between pachydrusen, recently proposed extracellular deposits associated with the thick choroid, and the risk of development of PCV. Many recent studies on diagnosis of PCV have focused on applying criteria from noninvasive multimodal retinal imaging without requirement of indocyanine green angiography. There have been attempts to develop deep learning models, a recent subset of artificial intelligence, for detecting PCV from different types of retinal imaging modality. Some of these deep learning models were found to have high performance when they were trained and tested on color retinal images with corresponding images from optical coherence tomography. The treatment of PCV is either a combination therapy using verteporfin photodynamic therapy and anti-vascular endothelial growth factor (VEGF), or anti-VEGF monotherapy, often used with a treat-and-extend regimen. New anti-VEGF agents may provide more durable treatment with similar efficacy, compared with existing anti-VEGF agents. It is not known if they can induce greater closure of polypoidal lesions, in which case, combination therapy may still be a mainstay. Recent evidence supports long-term follow-up of patients with PCV after treatment for early detection of recurrence, particularly in patients with incomplete closure of polypoidal lesions.

Polypoidal Choroidal Vasculopathy: An Update on Diagnosis and Treatment

Polypoidal choroidal vasculopathy (PCV) is a vascular disease of the choroid that leads to hemorrhagic and exudative macular degeneration. It may cause significant vision loss and thus affect the quality-of-life and psychological well-being. Non-invasive, non-ICGA-based OCT criteria have shown reliable results to plan adjunct photodynamic therapy (PDT) treatment, with the complete and consistent coverage of polypoidal lesions (PL) and branching neovascular network (BNN). The safety and efficacy of anti-vascular endothelial growth factor (anti-VEGF) monotherapy and its combination with verteporfin PDT have been established. However, treatment is still challenging due to frequent follow-ups, non-availability of PDT, and need for multiple anti-VEGF injection visits that increase the treatment burden and lead to patients being lost to follow-up. Effective treatments that prolong intervals between injections while maintaining vision and anatomical gains remain a critical unmet need. Longer acting molecules, like brolucizumab, have shown non-inferiority in BCVA gains and superior anatomical outcomes compared to other anti-VEGF agents. Newer therapies in the pipeline to enhance the efficacy and longevity of treatment include Faricimab and a port delivery system (PDS). This review summarizes the most recent diagnostic and treatment approaches in PCV to offer better treatment avenues.

Comparison of Indocyanine Green Angiography and Optical Coherence Tomography Angiography for Polypoidal Choroidal Vasculopathy

Purpose: To assess the diagnostic value of optical coherence tomography angiography (OCTA), and the factors affecting the diagnosis of polypoidal choroidal vasculopathy (PCV) by OCTA and indocyanine green angiography (ICGA). Methods: The numbers and area of polyps, and the presence and area of a branched vascular network (BVN) as revealed by ICGA and OCTA, were retrospectively analyzed in 43 patients with active PCV. The patients were divided into two groups according to whether the number of polyps matched between the two methods: group 1, equal number of polyps revealed by ICGA and OCTA; group 2, different number of polyps revealed by ICGA and OCTA. Results: In 43 PCV patients, the total number of polyps was 1.47 ± 0.83 in ICGA and 1.07 ± 0.91 in OCTA (<i>p</i> < 0.001), and the polyp area was 0.27 ± 0.42 mm² in ICGA and 0.17 ± 0.15 mm² in OCTA (<i>p</i> = 0.023). BVN was found in 33 eyes (76.7%) by ICGA and 29 eyes (67.4%) by OCTA (<i>p</i> < 0.001). The BVN area was 3.61 ± 2.59 mm² in ICGA and 2.74 ± 2.76 mm² in OCTA (<i>p</i> = 0.002). Central retinal thickness and central choroidal thickness were significantly greater in group 2 than group 1 (<i>p</i> < 0.001, respectively). Subretinal fluid (SRF) (<i>p</i> = 0.009) and subretinal hemorrhage (SRH) (<i>p</i> = 0.005) were significantly more prevalent in group 2 than group 1. Polyp height (<i>p</i> = 0.022) and diameter (<i>p</i> = 0.042) were significantly greater in group 2 than group 1. Conclusions: OCTA is a supplementary diagnostic technique for detecting PCV. The presence of SRF and SHR, and large polyp height and diameter, were associated with the polyp detection rate of OCTA for PCV.

Latest Developments in Polypoidal Choroidal Vasculopathy: Epidemiology, Etiology, Diagnosis, and Treatment

Polypoidal choroidal vasculopathy (PCV) is a condition characterized by multiple, recurrent, serosanguineous pigment epithelial detachments, and neurosensory retinal detachments due to abnormal aneurysmal neovascular lesions. It is generally considered as a variant of neovascular age-related macular degeneration, but there are some differences between the clinical presentation, natural history, and treatment response between patients with PCV and typical neovascular age-related macular degeneration patients. Over the past decade, new research and technological advancements have greatly improved our understanding of the PCV disease process and the management of PCV. This review aims to summarize the recent research findings to highlight the epidemiology, pathogenesis, genetics, the application of various diagnostic tools for PCV, and the available treatment options for PCV.