呼吸运动对PET/CT显像诊断右上腹病灶的影响

目的探讨呼吸运动对PET／CT全身显像诊断右肺底、肝顶病灶的影响。方法回顾分析100例胸部病变患者的^18F-脱氧葡萄糖（FDG）PET／CT显像结果，观察PET、CT及两者融合图像。患者在检查时平静呼吸。观察呼吸运动伪影在不同断面的特点，对右上腹可能出现定位误差的病灶加做常规屏气CT扫描。结果①6例患者因合并胸腔、腹腔积液而未列入统计，其余38．3％（36／94例）的患者PET／CT图像有明显的呼吸运动伪影，矢状面是观察呼吸运动伪影的最佳断面：②呼吸运动致肝顶在矢状面表现为“波浪状”，横断面表现为肝脏边缘模糊，冠状面表现为突入肺底的软组织密度影。③5例患者存在右肺底、肝顶病灶，其定位可能因呼吸运动造成误差。结论呼吸运动伪影是PET／CT显像中常见的现象，对右上腹病灶定位有疑问者应加做常规屏气CT扫描。

Effect of respiration motion on right upper abdominal lesion in PET/CT whole body scan

Objective To study the mis-localization of right upper abdominal lesions caused by respiration in PET/CT whole body scan. Methods 100 18F-fluorodeoxyglucose ( FDG) PET, CT and PET/CT fusion images of consecutive thoraxic lesions underwent retrospective analyses. CT scan was performed in quiet respiration for attenuation correction and fusion. If mis-localization was suspected in right lung base and diaphragm, ordinary CT scan with breath-holding was acquired. Results Of all the 94 patients, 6 patients were excluded because of ascites or pleural effusion. (1)36/94(38. 3% ) of the patients had significant breathing artifact observed in sagittal and coronal slice, especially the sagittal section. (2) Respiration caused dome of diaphragm in ' wavy' like shape in sagittal, blurring of the liver edge in transax-lal, soft tissue shadow dip into base of lower lung in coronal section. (3)5 cases lesions were mis-located but further studied by ordinary CT, 4 masses proved locate in lungs, one in liver. Conclusions The respiration artifact is usually observed in PET/CT scan. When mis-localization of right abdominal lesions is suspect, ordinary CT with breath-holding must be added.