18F-FDG PET全身显像时颈背部肌肉对称性浓聚分析

目的 分析^18F-脱氧葡萄糖(FDG) PET全身显像时部分患者颈部及胸椎两旁肌肉局限性代谢增高的显像特点及规律。方法 回顾性分析行^18F-FDG PET全身显像者1600例。受检者禁食4h后，按体重5．55MBq／kg静脉注入^18F-FDG，坐位松弛状态下休息50min后，用Siemens ECAT EXACTHR’PET仪进行采集。结果 1600例受检者中，共有9例10次显示双侧颈根部及双侧锁骨上区对称性放射性浓聚，同时均伴有胸椎两侧对称性点状浓聚。1例5d后行镇静剂介入显像，颈锁部及胸椎旁高代谢灶基本消失。结论 肌肉紧张可使少数患者颈部及胸椎两旁肌肉局限性^18F-FDG摄取增高。认识其显像特征有利于避免误诊。

Symmetrically increased uptake of 18F-FDG in the neck and thoracic paravertebral regions

Objective To analysis the pattern and the origin of symmetrically increased uptake of 18F-FDG in the neck and thoracic paravertebral regions in some patients referred for whole-body PET. Methods 1 600 consecutive patients who had undergone whole-body 18F-fluorodeoxyglucose (FDG) PET imaging were retrospectively reviewed. PET study was performed using a Siemens ECAT EXACT HR+ PET. After the intravenous administration of 18F-FDG (5.55 MBq/kg), PET imaging was performed on 3 - 7 bed positions with 2D acquisition and OSEM reconstruction. Results Nine patients (10 times of imaging) of 1 600 patients(0.625%) showed symmetrical FDG uptake in the neck standard uptake value (SUV) 1.20-7.97] and paravertebral regions (SUV 2.10-7.19). The purpose of PET imaging in 5 patients was regular physical examination. Of the remaining 4 patients, 1 patient was suspected to have liver tumor and was excluded clinically afterwards, 1 patient was with lung cancer, 1 patient was with Hodgkin's disease, and 1 patient with fibroma durum in right neck. All 9 patients were restud-ied with oral diazepam intervention before injection of FDG, and the abnormal uptake foci disappeared then. After following up for 1.5-18 months, all 9 patients were found to have no uptake abnormalities in the neck and paravertebral regions. Conclusions The characteristic pattern of symmetrically increased neck and paravertebral uptake of 18F-FDG is thought to be resulted from the uptake in contracting skeletal muscle in patients under stress. It is therefore important to accurately define patterns of physiological uptake of FDG to avoid false-positive results. Oral diazepam can be used in some patients when it is necessary to avoid the masking of potential abnormalities by this kind of characteristic uptakes.