From the *Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital; and †Harvard Medical School, Boston, MA.
Clin Nucl Med. 2016 Apr;41(4):274-7. doi: 10.1097/RLU.0000000000001127.
Increased 67Ga uptake in the mediastinal/hilar lymph nodes ("lambda") and in the lacrimal/parotid/submandibular glands ("panda") often coexists in patients with sarcoidosis (Sarc-Pts). However, we observed that increased lacrimal/salivary uptake is uncommon on 18F-FDG PET/CT (FDG-panda) in many Sarc-Pts who showed increased mediastinal/hilar uptake (FDG-lambda). We evaluated parotid and lacrimal FDG activity in Sarc-Pts who showed FDG-lambda in comparison with a control patient group and attempted to find underlying mechanisms to explain the discrepancy between FDG and Ga uptake in these organs.
Parotid FDG activity (FDG-P) was assessed visually using a 0- to 3-point scale (0 being = or minimally > background, and 3 > liver) and quantitatively using SUVmean in 52 confirmed Sarc-Pts with FDG-lambda (lambda group) as well as in 52 non-Sarc-Pts (control group). Lacrimal FDG activity (FDG-L) was assessed visually (0 being = or minimally > subcutaneous tissue, and 1 clearly > subcutaneous tissue).
There was no significant difference in the parotid SUVmean between lambda (1.88 ± 0.65) and control (1.76 ± 0.62) groups (P = 0.333). Also, there was no difference in visually graded FDG-P between the 2 groups (P = 0.257). None of the patients in all groups showed apparently abnormal (grade 1) FDG-L.
Increased FDG-L/FDG-P is rare in Sarc-Pts demonstrating FDG-lambda, which is strikingly different from the clinical experience as well as the reported data on Ga scintigraphy. Discrepancy in various cytokine levels between lacrimal samples and intrathoracic lesions in Sarc-Pts reported in the literature appears to correlate well with variable Ga and FDG uptake in the lacrimal gland and intrathoracic lesions.
在患有结节病（Sarc-Pts）的患者中，纵隔/肺门淋巴结（“lambda”）和泪腺/腮腺/颌下腺（“panda”）中的 67Ga 摄取增加通常同时存在。然而，我们观察到，在许多表现出纵隔/肺门摄取增加（FDG-lambda）的 Sarc-Pts 中，18F-FDG PET/CT（FDG-panda）上的泪腺/唾液腺摄取增加并不常见。我们评估了在 FDG-lambda 中显示 FDG-lambda 的 Sarc-Pts 中的腮腺和泪腺 FDG 活性，并与对照组患者进行了比较，并试图找到解释这些器官中 FDG 和 Ga 摄取之间差异的潜在机制。
使用 0-3 分制（0 为等于或略高于背景，3 为大于肝脏）对 52 例经证实的 Sarc-Pts（lambda 组）和 52 例非 Sarc-Pts（对照组）的腮腺 FDG 活性（FDG-P）进行视觉评估，并使用 SUVmean 进行定量评估。泪腺 FDG 活性（FDG-L）通过视觉评估（0 为等于或略高于皮下组织，1 为明显高于皮下组织）进行评估。
lambda 组（1.88±0.65）和对照组（1.76±0.62）之间的腮腺 SUVmean 无显著差异（P=0.333）。两组之间视觉分级 FDG-P 也无差异（P=0.257）。所有组的患者均未出现明显异常（分级 1）的 FDG-L。
在表现为 FDG-lambda 的 Sarc-Pts 中，泪腺 FDG-L/FDG-P 增加很少见，这与临床经验以及 Ga 闪烁扫描的报道数据明显不同。文献中报道的 Sarc-Pts 泪腺样本和胸内病变之间各种细胞因子水平的差异似乎与泪腺和胸内病变中 Ga 和 FDG 摄取的差异密切相关。
