QUANTIFICATION OF CHOROIDAL VASCULATURE BY HIGH-QUALITY STRUCTURE EN FACE SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY IMAGES IN EYES WITH CENTRAL SEROUS CHORIORETINOPATHY

Asymmetric choroidal vascular pattern in tilted disc syndrome

PURPOSE

To observe the choroidal vasculature in patients with tilted disc syndrome (TDS) using en face optical coherence tomography (OCT) and to evaluate the symmetry of the choroidal vascular pattern in the macular area.

METHODS

En face OCT was performed using a Plex Elite 9000 (Zeiss) with a 12 × 12 mm image of the macula, which was flattened with retinal pigment epithelium and segmented into choroidal layers. The middle/large choroidal vessels were evaluated for vertical symmetry qualitatively by the retina specialist coauthors and quantitatively by binarization analysis of choroidal vessel density and mean vessel diameter.

RESULTS

The 2 cases and 4 eyes (19.0%) that were difficult to segment due to the severe slope of the macular area were excluded. Of the 17 eyes in the remaining 13 cases, asymmetric middle/large choroidal vessels were observed in all eyes. Vessel density (P = 0.01) and mean vessel diameter (P < 0.01) of the choroidal middle/large vessels were significantly higher in the superior than in the inferior choroidal segmentation. Serous retinal detachment was observed in 4 eyes, all asymmetric cases.

CONCLUSION

Vertical asymmetry of the middle and large choroidal vessels is observed in most TDS patients. Circulatory imbalance due to choroidal vascular abnormalities in TDS may be one of the causes of serous retinal detachment.

KEY MESSAGES

What is known: Tilted disc syndrome is the congenital disease with ocular morphologic abnormalities associated with incomplete closure of the embryonic fissure of the eye at the inferior optic nerve head  Vertical cross-sectional optical coherence tomography images revealed that the choroid above the macula in tilted disc syndrome is relatively thickened, whereas the choroid within the inferior staphyloma is thinning.

WHAT IS NEW

  Evaluation of choroidal vascularity in tilted disc syndrome by en face optical coherence tomography revealed qualitatively and quantitatively highly dense choroidal vessels in the superior region, with larger diameter choroidal vessels than in the inferior region, and vertical asymmetry with an upward predominance.  Choroidal circulatory imbalance due to vertical asymmetry of the choroidal vessels may be one of the causes of serous retinal detachment in tilted disc syndrome.

Choroidal Vessel and Stromal Volumetric Analysis After Photodynamic Therapy or Focal Laser for Central Serous Chorioretinopathy

Purpose

To utilize volumetric analysis to quantify volumetric changes in choroidal vessels and stroma after photodynamic therapy (PDT) and focal laser photocoagulation (PC) for central serous chorioretinopathy (CSCR).

Methods

This retrospective, comparative study included 58 eyes (58 patients) with CSCR (PC, 33 eyes; PDT, 25 eyes) followed up with swept-source optical coherence tomography at 3 months after treatment. Three-dimensional (3D) choroidal vessel and stromal volumes in each area of the central 1.5-mm-diameter circle, the torus-shaped area with 6-mm-diameter circle excluding the area of the central 1.5-mm-diameter circle, and the treated area of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid centered at the fovea were analyzed using a deep learning-based method. Changes in volume at baseline and 1 and 3 months after treatment were compared.

Results

The mean patient age was 49.3 ± 10.5 years. In the central 1.5-mm-diameter circle, the mean vessel and stromal volume rates significantly decreased after the treatment in both the PDT and PC groups (P = 0.00029 and P = 0.0014, respectively), and significant differences between the PDT and PC groups of continuous variables within times were observed in both volumes (P = 0.024 and P = 0.037, respectively). In the torus-shaped area and treated area, the PDT and PC groups both showed similar decreases in vessel and stromal volume over time.

Conclusions

In the 3D optical coherence tomography volumetric analysis, both PDT and focal PC reduced choroid vessel volume in eyes with CSCR.

Translational Relevance

This new finding is useful in elucidating the pathogenesis and healing mechanisms of CSCR.

PERIPHERAL CHOROIDAL THICKNESS DETERMINED BY WIDEFIELD OPTICAL COHERENCE TOMOGRAPHY IN EYES WITH CENTRAL SEROUS CHORIORETINOPATHY

PURPOSE

To determine the central and peripheral choroidal thickness in eyes with central serous chorioretinopathy (CSC), and to compare these thicknesses values to those of control normal eyes.

METHODS

Widefield optical coherence tomographic (WF-OCT) images of 24 eyes of 19 CSC patients and 14 normal eyes of 7 individuals were recorded. A 20 mm vertical scan through the fovea was obtained with the Xephilio OCT S1 (Canon, Japan), a widefield OCT device. The subfoveal choroidal thickness (SCT), and the thickness at 5 mm superior (S5) and inferior (I5), 7 mm superior (S7) and inferior (I7), 8.5 mm superior (S8) and inferior (I8), and 10 mm superior (S10) and inferior (I10) from the fovea in the CSC eyes and normal eyes were compared.Results: There was no significant difference in the age (P=0.8) or the refractive error (P=0.7) between the CSC and normal eyes. The choroidal thickness was significantly thicker in the eyes with CSC than that in the normal eyes at SCT (P<0.01), S5 (P=0.01), and S7 (P=0.02). However, there was no significant difference in the choroidal thickness at the more peripheral points (all P>0.1).

CONCLUSION

The thickened choroid in CSC was observed at the fovea and the area just superior to the fovea. The pathogenesis of CSC may be associated with the choroidal thickening confined to the fovea and superior foveal area.

Depleted HDAC3 attenuates hyperuricemia-induced renal interstitial fibrosis via miR-19b-3p/SF3B3 axis

Dysfunctional histone deacetylases (HDACs) elicit unrestrained fibrosis and damage to organs. With regard to the link between HDACs and fibrosis, this research is practiced to decipher the concrete mechanism of HDAC3 in hyperuricemia (HN)-induced renal interstitial fibrosis (RIF) from microRNA-19b-3p/splicing factor 3b subunit 3 (miR-19b-3p/SF3B3) axis.The HN model was established on rats to induce RIF by oral administration of adenine and potassium oxalate. HN rats were injected with miR-19b-3p- or HDAC3-related vectors to figure out their effects on RIF through detecting 24-h urine protein, uric acid (UA), blood urea nitrogen (BUN) and serum creatinine (Scr) contents and α-smooth muscle actin (α-SMA), transforming growth factor β1 (TGF-β1) and fibronectin (FN) contents in renal tissues and observing pathological damages and RIF index of renal tissues. HDAC3, miR-19b-3p and SF3B3 expression in renal tissues were tested, along with their interactions.Elevated HDAC3 and SF3B3 and reduced miR-19b-3p were displayed in renal tissues of HN rats. Suppressed HDAC3 or promoted miR-19b-3p relieved HN-induced RIF, as reflected by their inhibitory effects on 24 h urine protein, UA, BUN, Scr, α-SMA, TGF-β1, and FN contents and RIF index and their ameliorated effects on pathological damages of renal tissues. HDAC3 bound to the promoter of miR-19b-3p to regulate SF3B3. MiR-19b-3p depletion abrogated down-regulated HDAC3-induced effects on HN-induced RIF.It is delineated that depressed HDAC3 relives HN-induced RIF through restoring miR-19b-3p and knocking down SF3B3, replenishing the references for RIF curing.

Multimodal Imaging in Pachychoroid Spectrum

Diagnostic investigation on pachychoroid spectrum disease (PSD) has been growing along with the rapid advancement of imaging technology. In optical coherence tomography (OCT)-based studies, choroidal thickness profile, luminal and stromal choroidal ratio, and abnormalities in the neurosensory retina have demonstrated various patterns in different clinical entities related to PSD. The emerging role of OCT angiography (OCTA) has been expanded to involve the quantitative analysis of the OCTA parameters in different clinical entities of PSD and to evaluate the choriocapillaris signal void and vessel density as indicators of choriocapillaris ischemia. OCTA has broadened our knowledge in characterization and assessment of both active and quiescent choroidal neovascularization and its association with treatment response. Recent studies using indocyanine green angiography (ICG) have focused on the evaluation of choroidal vascular hyperpermeability and its relationship with other pachychoroid related features. Ultrawidefield ICG enables observation and characterization of peripheral choroidal pathologies and their associations with macular abnormalities. Multicolor imaging is an emerging modality with the capability to demonstrate early abnormalities in PSD. We summarize all investigations reflecting the new insights into the application of multimodal imaging for PSD and focuses on novel findings observed in different clinical entities with each imaging modality.

Diagnosis of central serous chorioretinopathy by deep learning analysis of en face images of choroidal vasculature: A pilot study

Purpose

To diagnose central serous chorioretinopathy (CSC) by deep learning (DL) analyses of en face images of the choroidal vasculature obtained by optical coherence tomography (OCT) and to analyze the regions of interest for the DL from heatmaps.

Methods

One-hundred eyes were studied; 53 eyes with CSC and 47 normal eyes. Volume scans of 12×12 mm square were obtained at the same time as the OCT angiographic (OCTA) scans (Plex Elite 9000 Swept-Source OCT^®, Zeiss). High-quality en face images of the choroidal vasculature of the segmentation slab of one-half of the subfoveal choroidal thickness were created for the analyses. The 100 en face images were divided into 80 for training and 20 for validation. Thus, we divided it into five groups of 20 eyes each, trained the remaining 80 eyes in each group, and then calculated the correct answer rate for each group by validation with 20 eyes. The Neural Network Console (NNC) developed by Sony and the Keras-Tensorflow backend developed by Google were used as the software for the classification with 16 layers of convolutional neural networks. The active region of the heatmap based on the feature quantity extracted by DL was also evaluated as the percentages with gradient-weighted class activation mapping implemented in Keras.

Results

The mean accuracy rate of the validation was 95% for NNC and 88% for Keras. This difference was not significant (P >0.1). The mean active region in the heatmap image was 12.5% in CSC eyes which was significantly lower than the 79.8% in normal eyes (P<0.01).

Conclusions

CSC can be automatically diagnosed by DL with high accuracy from en face images of the choroidal vasculature with different programs, convolutional layer structures, and small data sets. Heatmap analyses showed that the DL focused on the area occupied by the choroidal vessels and their uniformity. We conclude that DL can help in the diagnosis of CSC.

Assessment of choriocapillary blood flow changes in response to half-dose photodynamic therapy in chronic central serous chorioretinopathy using optical coherence tomography angiography

Background

Optical coherence tomography angiography (OCTA) is a newly developed imaging quantitative technique for analysis of choriocapillaris (CC) flow changes, thereby exploring the pathological mechanism of chronic central serous chorioretinopathy (CCSC) and the therapeutic effects of photodynamic therapy (PDT). In this study, we sought to quantify the blood flow changes in CC of CCSC patients receiving half-dose PDT using OCTA.

Methods

A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled in this study. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, the CC patterns in response to PDT at early stage and the subsequent morphologic changes were qualitatively documented using OCTA.

Results

For affected eyes, FSV at 6-m follow-up was significantly lower than that at 1-m follow-up (p = 0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p < 0.05 for all), and FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p < 0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level.

Conclusion

Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.

Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification

Binarization is a critical step in analysis of retinal optical coherence tomography angiography (OCTA) images, but the repeatability of metrics produced from various binarization methods has not been fully assessed. This study set out to examine the repeatability of OCTA quantification metrics produced using different binarization thresholding methods, all of which have been applied in previous studies, across multiple devices and plexuses. Successive 3 × 3 mm foveal OCTA images of 13 healthy eyes were obtained on three different devices. For each image, contrast adjustments, 3 image processing techniques (linear registration, histogram normalization, and contrast-limited adaptive histogram equalization), and 11 binarization thresholding methods were independently applied. Vessel area density (VAD) and vessel length were calculated for retinal vascular images. Choriocapillaris (CC) images were quantified for VAD and flow deficit metrics. Repeatability, measured using the intra-class correlation coefficient, was inconsistent and generally not high (ICC < 0.8) across binarization thresholds, devices, and plexuses. In retinal vascular images, local thresholds tended to incorrectly binarize the foveal avascular zone as white (i.e., wrongly indicating flow). No image processing technique analyzed consistently resulted in highly repeatable metrics. Across contrast changes, retinal vascular images showed the lowest repeatability and CC images showed the highest.

Age-Related Changes in Choroidal Thickness and the Volume of Vessels and Stroma Using Swept-Source OCT and Fully Automated Algorithms

PURPOSE

To determine age-related changes in choroidal thickness and the volume of choroidal vessels and stroma using automated algorithms based on structural swept-source OCT (SS-OCT) scans.

DESIGN

Prospective and observational study.

PARTICIPANTS

The study included 144 normal participants with ages ranging from 20 to 88 years.

METHODS

A previously reported strategy was used to automatically segment the choroid using SS-OCT structural images. Attenuation correction was applied on B-scans to enhance the choroidal contrast and facilitate more accurate automatic segmentation of the 3-dimensional choroidal vessel and stroma. The parameters that we investigated included mean choroidal thickness (MCT), choroidal vessel volume (CVV), choroidal stroma volume (CSV), choroid vascularity index (CVI), and the choroidal stroma-to-vessel volume ratio (CSVR). Correlations between MCT and choroidal vessel metrics of CVV, CSV, CVI, and CSVR were studied. Regional distributions of MCT and CVI were analyzed using a grid centered on the fovea. Age-related changes in MCT, CVV, CSV, and CVI were studied in the entire scanning region, as well as in the subregions of the grids.

MAIN OUTCOME MEASURES

Age-related changes in MCT, CVV, CSV, and CVI using 6×6-mm and 12×12-mm SS-OCT scans.

RESULTS

The automated choroid segmentations were validated against manual segmentations, and MCT measurements were shown to be in good agreement (P < 0.0001). Choroidal vessel volume and CSV showed significant correlations with MCT (all P < 0.0001). Interestingly, CVI and CSVR were constant, with little variation among all participants regardless of age and MCT (61.1±1.8% and 0.64±0.05, respectively). Measurements on 12×12-mm and 6×6-mm scans showed excellent agreement in all scan regions (all P < 0.0001). While choroidal thickness and choroidal volume, which includes both choroidal vessels and stroma, decrease with age (all P < 0.0001), the CVI and CSVR vary little among all ages in all regions.

CONCLUSIONS

Whereas MCT, CVV, and CSV decrease with age, the CVI and CSVR remain constant in all regions with age. Ongoing studies are using these automated algorithms on SS-OCT structural datasets to investigate the diagnostic usefulness of these choroidal parameters in a myriad of ocular and systemic diseases.