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Updated: Jun 16, 2026
Implantation and Evaluation of Melanoma in the Murine Choroid via Optical Coherence Tomography
Published on: December 2, 2022
A Framework for Standardized Manual Segmentation and Measurement of Uveal Melanoma on Ultrasound
William F Chadwick1, Sanjay Ganesh1, Albert K Dadzie2
1Department of Ophthalmology and Visual Sciences, University of Illinois Chicago, Chicago, Illinois.
Purpose:
To develop and validate a standardized manual segmentation protocol for delineating choroidal tumors on B-scan ultrasonography to improve measurement reproducibility in uveal melanoma.
Design:
Cross-sectional reproducibility study.
Participants:
Two hundred seventy five ultrasound images of melanocytic choroidal tumors obtained from a single tertiary ocular oncology clinic.
Methods:
Two independent reviewers performed manual segmentation using an iterative, consensus-based annotation workflow, adjudicated and validated by an ocular oncologist. Inter-reviewer and intrareviewer agreement was assessed using surface-based metrics including average symmetric surface distance (ASSD), 95th percentile Hausdorff distance (HD95), and normalized surface distance (NSD). The resulting layer segmentations were used to derive geometric tumor measurements including tumor height and largest basal diameter (LBD) measured using both a 1-chord and arc-length approach.
Main Outcome Measures:
Inter-reviewer and intrareviewer agreement (ASSD, HD95, and NSD) and mean absolute error for derived tumor thickness and LBD measurements.
Results:
The consensus protocol identified 4 consistent anatomical boundaries: inner retina, inner tumor margin, outer tumor margin, and outer sclera. Average inter-reviewer agreement across all classes was high, with ASSD: 0.14 mm, HD95: 0.49 mm, and NSD at 0.2 mm: 81%. Most disagreement occurred at the scleral interface and in cases with shadowing, artifact, subretinal fluid, or mushroom shape. Derived tumor measurements demonstrated low mean absolute errors of 0.21 mm, 0.59 mm, and 0.72 mm for thickness, 1-chord LBD, and arc-length LBD, respectively.
Conclusions:
A standard, operationalized segmentation protocol enables reproducible boundary delineation on ophthalmic ultrasound and provides a foundation for consistent tumor measurement and future computational automation.
Financial Disclosures:
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
