T2 mapping histogram at extraocular muscles for predicting the response to glucocorticoid therapy in patients with...

To evaluate the performance of T2 mapping histograms at the extraocular muscles (EOMs) in predicting the response to glucocorticoid therapy in the patients with active and moderate-severe thyroid-associated ophthalmopathy (TAO).

Thirty active and moderate-severe TAO patients (responsive group, n=20; unresponsive group, n=10) were enrolled, and evaluated using T2 mapping before treatment. Histogram parameters (mean, median, max, min, 10th, 90th percentiles, skewness, and kurtosis) of T2 relaxation time (T2RT) at the EOMs for each orbit, and clinical variables (age, sex, disease duration, anti-thyroid treatment, smoking habit, pre-treatment thyroid function, thyrotrophin receptor antibody, diplopia presence, activity and severity scores) were collected and compared between groups. Logistic regression and receiver operating characteristic (ROC) curve analyses were used to assess the predictive value of identified independent variables for treatment response.

The responsive group showed significantly shorter disease duration (p=0.003), while higher T2RT_min than unresponsive group (p<0.001). Multivariate analysis showed that T2RT_min and disease duration were independent predictors for responsive TAOs. ROC curve analyses indicated that setting a cut-off value of ≥54.3 for T2RT_min demonstrated the optimal predicting specificity for responsive TAOs (100%), while a combination of T2RT_min ≥54.3 and disease duration ≤4.5 showed optimal predicting efficiency and sensitivity (area under the curve, 0.820; sensitivity, 65%).

Histogram analysis can help to exhibit the heterogeneity of T2RT at the EOMs. T2RT_min, together with disease duration may be the promising marker for predicting response to glucocorticoid therapy in the patients with active and moderate-severe TAO.