Department of Nuclear Medicine, University Hospital Essen, Essen, Germany.
Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany.
Graefes Arch Clin Exp Ophthalmol. 2021 Oct;259(10):3107-3117. doi: 10.1007/s00417-021-05339-1. Epub 2021 Aug 18.
Currently, therapeutic management of patients with Graves' orbitopathy (GO) relies on clinical assessments and MRI. However, monitoring of inflammation remains difficult since external inflammatory signs do not necessarily represent the orbital disease activity. Therefore, we aimed to evaluate the diagnostic value of F-FDG-PET/MRI to assess the inflammation of GO patients.
Enrolled patients with new onset of GO underwent ophthalmological examinations to evaluate the activity (CAS) and severity of GO (NOSPECS), as well as an F-FDG-PET/MRI (Siemens Biograph mMR) with dual time point imaging (immediately post-injection and 60 min p.i.). A subset of PET parameters including maximum standardized uptake value (SUVmax), metabolic target volume (MTV), and total lesion glycolysis (TLG) were obtained separately per eye and per extraocular eye muscle (EOM). EOM thickness was measured on the co-registered MRI.
Of 14 enrolled patients, three showed mild, seven moderate-to-severe, and four sight-threatening GO. Patients with severe GO showed statistically significant higher TLG than patients with mild GO (p = 0.02) and higher MTV than patients with mild (p = 0.03) and moderate (p = 0.04) GO. Correlation between NOSPECS on one hand and MTV and TLG on the other was significant (R = 0.49-0.61).
TLG and MTV derived from FDG-PET appear to be good discriminators for severe vs. mild-to-moderate GO and show a significant correlation with NOSPECS. As expected, PET parameters of individual eye muscles were not correlated with associated eye motility, since fibrosis, and not inflammation, is mainly responsible for restricted motility. In conclusion, F-FDG-PET/MRI can be used for assessment of GO inflammation.
目前，Graves 眼病（GO）患者的治疗管理依赖于临床评估和 MRI。然而，由于外部炎症迹象并不一定代表眼眶疾病的活动，因此监测炎症仍然很困难。因此，我们旨在评估 F-FDG-PET/MRI 评估 GO 患者炎症的诊断价值。
新发病例的 GO 患者接受眼科检查，以评估活动度（CAS）和 GO 的严重程度（NOSPECS），并进行 F-FDG-PET/MRI（Siemens Biograph mMR）双时相成像（注射后立即和 60 分钟后）。分别获得每只眼睛和每只眼外肌（EOM）的最大标准化摄取值（SUVmax）、代谢靶体积（MTV）和总病变糖酵解（TLG）等 PET 参数。EOM 厚度在配准的 MRI 上进行测量。
14 名入组患者中，3 名患者为轻度，7 名患者为中重度至重度，4 名患者为视力威胁性 GO。重度 GO 患者的 TLG 明显高于轻度 GO 患者（p=0.02），MTV 明显高于轻度（p=0.03）和中度（p=0.04）GO 患者。NOSPECS 与 MTV 和 TLG 之间存在显著相关性（R=0.49-0.61）。
来自 FDG-PET 的 TLG 和 MTV 似乎是区分重度与轻度至中度 GO 的良好指标，与 NOSPECS 呈显著相关性。正如预期的那样，单个眼外肌的 PET 参数与相关的眼球运动无关，因为纤维化而不是炎症主要导致运动受限。总之，F-FDG-PET/MRI 可用于评估 GO 炎症。
