对胸部病变的定位价值对胸部病变的定位价值

目的　探讨18F 脱氧葡萄糖 (FDG)PET发射和透射扫描图像融合对胸部病变的定位价值。方法　对 2 1例胸部肿瘤患者进行18F FDGPET肿瘤显像 ,图像重建后获得透射扫描和衰减校正后发射扫描各断面断层图像。计算机自动生成发射和透射扫描各断面断层图像双肺胸膜轮廓 ,采用表面轮廓匹配法进行图像融合。结果　在PET胸部透射扫描断层图像上可分辨出主动脉弓、气管、肺门大血管、心脏、肺组织、纵隔、胸壁等解剖结构。 2 1例患者在PET和CT图像上均检出的病灶共6 1个 ,与CT图像病灶位置对比 ,除后纵隔近脊柱旁 1个病灶在融合图像上难以定位外 ,余病灶均能正确定位。CT和融合图像相应横断面图像上病变中心点离胸壁前、后径和左、右径距离的平均差值分别为 (2 7± 0 8)、(2 4± 0 9)、(2 9± 0 5 )和 (2 1± 0 4)mm。结论　PET胸部发射和透射扫描图像融合对胸部病变可作出正确定位。PET透射扫描不仅可用于衰减校正 ,还可用于图像融合 ,提供胸部解剖结构信息。

Evaluation of emission-transmission registration in FDG PET images for localization of chest lesions

Objective　To evaluate emission-transmission registration for localization of chest lesions. Methods　PET and CT studies were acquired from 21 patients.The pleural surfaces in both emission and transmission image sets were determined by surperficial contour match method.The algorithm used for image registration was the surface-fitting algorithm.The anterior-posterior diameter(a-p) and left-right diameter(l-r) through the center of foci were measured in corresponding CT and PET transverse images. Results　61 lesions were detected in both PET and CT images.All lesions were accurately localized in lung,mediastinum and chest wall,except one mediastinum lesion near thoracic vertebral column.The differences between a-p and l-r value in PET and CT images were (2.7±0.8) mm,(2.4±0.9) mm,and (2.9±0.5) mm, (2.1±0.4) mm respectively.　ConclusionEmission-transmission registration provided extra anatomical information to chest PET image,and can accuratelylocalized the chest lesions.