99mTc-DTPA眼眶SPECT/CT对甲状腺相关性眼病泪腺炎症的评估价值

目的：探讨99m锝-二亚乙基三胺五乙酸(99mTc-diethylene triamine pentaacetic acid，99mTc-DTPA)单光子发射型计算机断层显像/计算机断层扫描(single photon emission computed tomography/computed tomography，SPECT/CT)在甲状腺相关性眼病(thyroid associated ophthalmopathy，TAO)患者泪腺炎症中的应用价值。方法：回顾性分析58例TAO患者的临床资料，根据临床活动评分(clinical active score，CAS)标准分为活动期组和非活动期组，同时选取影像学表现阴性的12例为对照组。所有患者行99mTc-DTPA眼眶SPECT/CT，分别在横断面、冠状面图像上测量泪腺横径、长径、体积，勾画泪腺与枕叶脑组织的感兴趣区，测量放射性计数平均值，计算靶/非靶比值(target/non-target ratio，T/NT)，比较3组间泪腺参数的差异，并评价各参数对TAO活动性的诊断效能。结果：与对照组比较，除TAO非活动期组冠状面长径和T/NT值外，TAO患者各泪腺参数均明显增长或增高(P<0.05)；与非活动组比较，除横断面和冠状面长径外，活动期组其余参数均明显增长或增高(P<0.05)；除冠状面长径外，TAO患者泪腺参数均与CAS呈正相关，以横断面T/NT最大值的诊断效能最优(曲线下面积为0.82，P<0.01)。结论：99mTc-DTPA 眼眶SPECT/CT作为一种无创性影像学方法，有助于评估TAO患者泪腺炎症程度及临床活动期分期。

Efficacy of 99mTc-DTPA orbital SPECT/CT on the evaluation of lacrimal gland inflammation in patients with thyroid associated ophthalmopathy

Objective: To investigate the values of orbital single photon emission computed tomography/computerized tomography (SPECT/CT) with 99mTc-diethylene triamine pentaacetic acid (99mTc-DTPA) on the evaluation of lacrimal gland inflammation in patients with thyroid associated ophthalmopathy (TAO). Methods: A total of 58 TAO patients were retrospectively recruited for this study, all of whom were categorized into all active group and all inactive group based on the clinical active score (CAS). Another 12 patients with the negative images on SPECT/CT served as a normal control group (NC). All patients were undergone the 99mTc-DTPA orbit SPECT/CT. Quantitative parameters of lacrimal gland including width, length, volume, and the count ratio of region of interest (ROI) drawn on lacrimal gland to the region of occipital brain (target/non-target ratio, T/NT), were measured on axial and coronal slices, respectively. Quantitative parameters were compared among the 3 groups, and the diagnostic value on discrimination of TAO patients from inactive to active ones was evaluated. Results: All parameters in TAO patients (except the length on coronal slices and the mean radioactive counts of axial T/NT in the TAO inactive group) were much greater than those in the NC group (P<0.05). All parameters in the TAO active group (except the length on axial and coronal slices) were much greater than those in the TAO inactive group (P<0.05). There were significant lineal positive correlations between the parameters in all TAO patients (except the length on coronal slices ) and CAS. The best diagnostic value was detected by the max radioactive counts of axial T/NT (area under the curve=0.82, P<0.01). Conclusion: As an invasive imaging modality, 99mTc-DTPA orbital SPECT/CT is helpful to estimate the lacrimal gland inflammation and to assess the disease activity in TAO patients.