ROLE OF ORBITAL COLOR DOPPLER IMAGING IN THE EVALUATION OF THYROID-ASSOCIATED EYE DISEASE

Background: Thyroid-associated eye disease (TAED) is an autoimmune orbital disorder in which timely identification ofactive inflammation is essential for appropriate treatment. Colour Doppler Imaging (CDI) provides a non-invasive method forevaluating orbital haemodynamics and may assist in assessing disease activity. Materials and Methods: This hospital-basedcross-sectional study included 90 adults with TAED. Disease activity was classified using the European Group on Graves'Orbitopathy (EUGOGO) Clinical Activity Score (CAS) into active (CAS ≥3; n=23) and inactive (CAS <3; n=67) groups.Colour Doppler Imaging was performed to evaluate the ophthalmic artery (OA), central retinal artery (CRA), and superiorophthalmic vein (SOV). Doppler parameters were compared between groups, and receiver operating characteristic (ROC)analysis was used to determine their diagnostic performance. Results: Active TAED demonstrated significantly higher OApeak systolic velocity and end-diastolic velocity with lower resistive index than inactive disease (all p<0.001). CRA peaksystolic velocity was also significantly increased in active TAED, whereas SOV maximum and minimum velocities weremarkedly reduced (all p<0.001), indicating orbital venous congestion. ROC analysis showed excellent diagnostic performanceof SOV V1 (AUC=0.971), followed by SOV V2 (AUC=0.943) and CRA PSV (AUC=0.916), with OA parameters alsodemonstrating good discriminatory ability. Conclusion: Colour Doppler Imaging reliably detects orbital haemodynamicalterations associated with active TAED. As a safe, objective, and non-invasive imaging technique, CDI complements clinicalassessment and may aid in disease activity evaluation, treatment planning, and monitoring of therapeutic response.Keywords: Thyroid-associated eye disease, Colour Doppler Imaging, Ophthalmic artery, Central retinal artery,