Using quantitative T1rho mapping on extraocular muscles for assessing activity of thyroid-associated orbitopathy: preliminary observation

Motivation: Quantitative T1rho mapping holds promise in evaluating inflammatory myopathies, while its diagnostic performance in assessing extraocular muscles (EOM) involved in thyroid-associated orbitopathy (TAO) remains uncertain. Goal(s): To explore the utility of quantitative T1rho mapping in active TAO. Approach: T1rho imaging was performed on 20 active TAO patients and 12 healthy volunteers. The T1rho value of bilateral medial rectus and lateral rectus was measured and compared with T2. Results: T1rho of EOMs of active TAO patients increase significantly when compared to healthy volunteers. Quantitative T1rho mapping shows improved diagnosis performance in TAO than T2 mapping with a 10-fold reduction of total scanning time. Impact: First implementation of quantitative T1rho mapping in orbit MRI to evaluate TAO-affected EOMs.