Abstract Details

Title INI-32: A Computed Tomography Atlas of the Orbit for Reproducible Neuro-ophthalmic Research

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P10 - Poster Session 10 (8:00 AM-9:00 AM)

Poster/Presentation
Number 17-012

Objective To develop and validate a publicly available computed tomography (CT) atlas of the human orbit that can serve as a spatial reference framework for future neuro-ophthalmic imaging studies.

Background Quantitative imaging of orbital structures remains limited by the absence of a standardized reference space. While brain imaging benefits from well-established public atlases, no analogous dataset exists for the orbit. This lack of a common template hinders reproducibility in studies involving orbital volumetrics, segmentation algorithms, and disease-related morphometrics.

Design/Methods 16 normal orbital CT scans (9 male, 7 female; mean age 52.8 years) were retrospectively selected from clinical archives. Each image was mirrored to create 32 standardized orbits, which were iteratively aligned using rigid, affine, and nonlinear registration with Advanced Normalization Tools. The resulting averaged image was manually segmented by expert neuroradiologists and ophthalmologists to label key orbital structures. Consensus segmentations were generated using the Simultaneous Truth and Performance Level Estimation algorithm. Atlas performance was evaluated using automated atlas-based segmentation on 32 additional normal orbits and 63 orbits from patients with thyroid eye disease (TED).

Results Atlas-based segmentation demonstrated high agreement with manual ground truth for normal orbits (Dice coefficient 0.80–0.95) and lower, yet acceptable, agreement in TED orbits (0.61–0.82). As expected, TED orbits exhibited significantly increased extraocular muscle and fat volumes compared with controls (p < 0.001). The final dataset, including labeled atlas and description files, is publicly available for research use.

Conclusions

INI-32 represents the first open-access CT atlas of the human orbit. This dataset provides a standardized spatial reference that supports reproducible orbital volumetric research and development of automated segmentation tools. It establishes a foundation for cross-study comparisons and future disease-specific atlas development in neuro-ophthalmology and neuroimaging.

Authors/Disclosures
Manisha Kotay, MD (VCU) PRESENTER	Dr. Kotay has nothing to disclose.
Vishal Patel (Mayo Clinic)	Vishal Patel has nothing to disclose.

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