Assessment of thyroid-associated ophthalmopathy activity using corrected standardised uptake value maximum (SUVmax) and uptake ratios from 99Tcm-diethylene triamine pentaacetic acid single photon emission computed tomography/computed tomography (99Tcm-DTPA SPECT/CT) imaging.

AIM: This study evaluated the utility of corrected maximum standardized uptake value (SUVmax) in assessing thyroid-associated ophthalmopathy (TAO) activity through 99Tcm-diethylene triamine pentaacetic acid (99Tcm-DTPA) SPECT/CT imaging.

MATERIALS AND

METHODS

A total of 166 orbits from 83 TAO patients were analyzed, alongside 22 orbits from 11 healthy controls. Participants were cate gorized into active (CAS ≥ 3), inactive (CAS <3), and control groups based on the clinical activity score (CAS). Corrected SUVmax and uptake ratios (UR) were quantitatively measured using Q.Metrix software. Statistical analyses, including Kruskale-Wallis tests, Spearman correlations, and ROC curve evaluations, were employed to examine group differences and diagnostic performance.

RESULTS

The corrected SUVmax and UR values were significantly higher in the active group compared to inactive and control groups (P<0.001). Corrected SUVmax demonstrated strong reproducibility (ICC = 0.958) and a positive correlation with CAS (rs = 0.537, P<0.001), outperforming UR in consistency (ICC = 0.632). ROC analysis revealed that the corrected SUVmax threshold of 10.440 offered 70.7% sensitivity and 82.1% specificity for predicting TAO activity. UR exhibited comparable diagnostic performance but with reduced reproducibility.

CONCLUSION

These findings highlight corrected SUVmax as a robust and reliable parameter for quantifying TAO inflammatoryactivity. Its strong correlation with CAS and high interobserver agreement establish its potential for clinical use in guiding TAO treatment and monitoring disease progression. Further multicenter studies are warranted to validate these findings and expand clinical applications.