Comparison of Current Optical Coherence Tomography Angiography Methods in Imaging Retinal Hemangioblastomas

Abstract

Purpose: To compare spectral-domain (SD) and swept-source (SS) optical coherence tomography angiography (OCTA) for imaging retinal capillary hemangioblastomas (RCHs) in von Hippel-Lindau disease (VHLD).

Methods: Prospective single-center cross-sectional study. Tumor size (TS) of perfused RCHs was assessed clinically in relation to the optic disc size. For both technologies, SD-OCTA and SS-OCTA, corresponding images with a scan size of 3 × 3 mm² and 6 × 6 mm², respectively, were overlaid according to the set of marker positions to determine the TS.

Results: From 200 patients with VHLD, 48 patients showed 84 RCHs. SD-OCTA images of 39 RCHs (46.4%) and SS-OCTA images of 48 RCHs (57.2%) were suitable for analysis. The average in OCTA-measured TS of 1.60 ± 2.58 mm² (range, 0.01-10.43) was congruent to the clinically assessed TS in 81.3% of cases (r = 0.86, P < 0.0001). TS measured in SD-OCTA compared to SS-OCTA showed similar values and a high correlation (all P < 0.0001). Nevertheless, despite the similarities, a slight trend in SS-OCTA was observed whereby with increasing TS, an elevated TS was detected compared to SD-OCTA (3 × 3-mm² scans: mean difference of 0.03 ± 0.04 mm², 6 × 6-mm² scans: 0.08 ± 0.19 mm²). However, within the same imaging technology method, TS values almost did not differ (SD-OCTA: mean difference of 0.01 ± 0.02 mm², SS-OCTA: 0.001 ± 0.01 mm²).

Conclusions: OCTA may serve as an additional tool for diagnosis and monitoring of RCHs. Nevertheless, due to the differences between the technologies, the values cannot be used interchangeably.

Translational relevance: SD-OCTA and SS-OCTA are suitable to detect and monitor RCHs and provide a more detailed assessment about the TS than this is clinically possible.

Keywords: OCT angiography; retinal capillary hemangioblastoma; spectral domain optical coherence tomography angiography; swept-source optical coherence tomography angiography; von Hippel-Lindau disease.

Figure 1.

Tumor annotation and area measurement. Tumor areas in corresponding images of the same retinal capillary hemangioblastoma (A–D) were manually outlined (E–H, yellow line). Marker positions (green dots) at corresponding prominent vessel intersections were annotated in all images. On the basis of these marker positions, the images to be compared were aligned.

Figure 2.

Flowchart of patients and RCHs included in the study.

Figure 3.

Localization and clinically estimated size of the detected 62 peripheral RCHs. The sizes were determined on the basis of vertical optic disc diameter (DD). In total, 84 RCHs were detected. Twenty-two of these were located peripapillary and are not shown. Suitable OCTA image was available for 17 peripapillary RCHs. For five peripapillary RCHs, OCTA imaging was not performed.

Figure 4.

RCH size measured with SS-OCTA versus SD-OCTA. Scatterplots (A–D) and Bland-Altman analyses (E–H) were used. For analyses of SS-OCTA compared to SD-OCTA of 3 × 3-mm² scans, data of 25 RCHs could be used. For analyses of SS-OCTA compared to SD-OCTA of 6 × 6-mm² scans, data of 36 RCHs could be used. For analyses of 3 × 3-mm² compared to 6 × 6-mm² SD-OCTA scans, data of 23 RCHs could be used. For analyses of 3 × 3-mm² compared to 6 × 6-mm² SS-OCTA scans, data of 28 RCHs could be used. (A–D) Fit spline analyses using four knots for the smoothing spline were conducted to generate the compensation curve. Pearson correlation coefficient (r) was analyzed. (E–H) Dashed lines represent average bias between the compared measurements, solid lines represent limits of agreement (LOA), and gray shading represents 95% confidence intervals for the bias and LOAs. ICC was analyzed. TS, tumor size.