Texture analysis of orbital magnetic resonance imaging for monitoring and predicting treatment response to glucocorticoids in patients with thyroid-associated ophthalmopathy

Abstract

Purpose: To evaluate the value of MRI-based texture analysis of extraoc ular muscle (EOM) and orbital fat (OF) in monitoring and predicting the res ponse to glucocorticoid (GC) therapy in patients with thyroid-associated ophthalmopathy (TAO). Methods: Thirty-seven active and moderate-to-severe TAO patients (respo nders, n = 23; unresponders, n = 14) were retrospectively enrolled. MRI-based texture parameters (entropy, uniformity, skewness and kurtosis) of EOM and OF were measured before and after GC therapy, and compared between groups. Correlations between the changes of clinical activity score (CAS) and imaging parameters before and after treatment were assessed. Receiver operating characteristic curves were used to evaluate the predictive value of identified variables. Results: Responsive TAOs showed significantly decreased entropy and incr eased uniformity at EOM and OF after GC therapy (P < 0.01), while unresponders showed no significance. Changes of entropy and uniformity at EOM and OF were significantly correlated with changes of CAS before and after treatment (P < 0.05). Responders showed significantly lower entropy and higher uniformity at EOM than unresponders before treatment (P < 0.01). Entropy and uniformity of EOM and disease duration we re identified as independent predictors for responsive TAOs. Combin ation of all three variables demonstrated optimal efficiency (area under curve, 0.80 2) and sensitivity (82.6%), and disease duration alone demonstrated optimal specifi city (100%) for predicting responsive TAOs. Conclusion: MRI-based texture analysis can reflect histopathological hetero geneity of orbital tissues. It could be useful for monitoring and predicti ng the response to GC in TAO patients.

Keywords

• thyroid-associated ophthalmopathy
• magnetic resonance imaging
• texture analysis
• treatment response