AUTHOR=Jiang Chengzhi , Deng Zilong , Huang Jin , Deng Haoyu , Tan Jia , Li Xinhui , Zhao Min 

TITLE=Monitoring and Predicting Treatment Response of Extraocular Muscles in Grave's Orbitopathy by 99mTc-DTPA SPECT/CT

JOURNAL=Frontiers in Medicine

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.791131

DOI=10.3389/fmed.2021.791131

ISSN=2296-858X

ABSTRACT=Objective: To investigate single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing inflammation in extraocular muscle (EOM) and predicting the therapeutic efficacy of periocular glucocorticoid therapy (PGT) for Graves’ ophthalmopathy (GO).
Materials and Methods: A total of 412 eyes from 206 GO patients referred for 99mTc-DTPA orbital SPECT/CT were enrolled. Fourteen age- and gender-matched healthy control (28 eyes) were included. The thickness and uptake ratio (UR) of the four EOMs were derived from SPECT/CT. Eighty-six eyes from GO patients received PGT. Changes in SPECT/CT parameters were evaluated between the pre- and post-treatment.
Results: 195 eyes and 217 eyes were classified as active and inactive stages by clinical activity score (CAS). The values of the thickness and UR of each EOM, Tmax and Umax were all significantly higher in the active GO than in the inactive GO and controls (p<0.01). Among 86 eyes (48 GO patients) included in the efficacy analysis, 56 eyes and 30 eyes were classified as responders and non-responders. Values of thicknesses and UR of each EOM, the maximum thickness (Tmax)  and the maximum UR (Umax) all dropped following PGT in the responders(p<0.01). Logistic regression analysis identified the Umax as an independent predictor for responders (p<0.01). Moreover, Umax demonstrated incremental predictive value over clinical characters and CAS as evidenced by the improved area under the curve (0.85 vs 0.78) and global chi-square (34.12 vs 18.1).
Conclusion: 99mTc-DTPA SPECT/CT have the promise to assess inflammatory activity by detecting involvement of EOMs in GO. Pre-treatment UR provide independent and incremental values for prediction PGT treatment response.