非小细胞肺癌PET／CT显像中非增强CT对FDG摄取阴性病灶的价值

目的：评价非小细胞肺癌PET／CT显像中非增强CT对FDG摄取阴性病灶的临床价值。材料和方法：回顾2006年5～12月期间在本中心接受^18F—FDG PET／CT检查并具有病理结果的119例非小细胞肺癌患者。记录FDG低，无摄取病灶即FDG摄取阴性病灶，根据Ford研究中的标准，分为有显著价值组、有部分价值组及无显著价值组3种。结果：119例非小细胞肺癌患者中，55．5％（66／119）为初次分期，44．5％（53／119）为治疗后再分期或疗效评价。283个FDG摄取阴性的异常病灶主要分布在头颈部（n=40）、胸部（n=97）、腹部和盆腔（n=128）、骨骼（n=18）。其中显著价值组n=9（3％）、部分价值组n=121（43％）、无显著价值组n=153（54％）。本次研究中检出9个有显著价值异常病灶，包插转移性肺结节4个、成骨性转移病灶1个、脑转移病灶1个、肝血管瘤1个和肾脏占位2个。结论：PET／CT中非增强CT扫描不仅可进行衰减校正和解剖定位，而且低剂量CT还可以提供一定的诊断信息；非小细胞肺癌患者FDG摄取阴性的异常病灶中仅少数病灶具有重要的价值，临床上需要进一步处理；诊断性CT无疑可得到更多的诊断信息。

Abnormalities with negative 18F-FDG uptake detected using non-enhanced CT of PET/CT in non-small cell lung cancer

Objective： To evaluate the clinical value of abnormalities that do not show increased ISF-FDG uptake on nonenhanced CT of integrated PET/CT in patients with non-small cell lung cancer. Materials and Methods： The study consisted of a retrospective analysis of consecutive PET/CT scans obtained at our PET center between May and December 2006. During the eight-month period, there were 119 patients had a diagnosis of non-small cell lung cancer. All scans Were obtained with integrated PET/CT scanner （Siemens Biograph Sensation 16）. Each case was interpreted independently by two experienced PET/ CT physicians. All abnormalities with negative ISF-FDG uptake were recorded. The abnormalities were classified as being of major, moderate or minor significance according to the definitions previously by Ford. Results： There were 119 patients with non-small cell lung cancer underwent initial staging（66/119, 55.5%）, restaging or treatment monitoring（53/119, 44.5%） PET/CT imaging during the study period. The abnormalities were located in the head and neck （n=40）, thorax （n=97）, abdomen and pelvis（n=128）, and bony skeleton（n=18）. The clinical importance of these abnormalities was classified as major n=9（3%）, moderate n=121 （42%）, or minor n=153 （54%）. Major abnormalities noted in the study included 4 cases of small lung nodules, 1 case of osteolytic lesion and 1 case of brain lesion suggestive of metastasis, as well as 1 case of liver mass and 2 cases of renal mass. Conclusions： CT scan in PET/CT can not be only a tool for attenuation correction and anatomic landmarks alone. Even low-dose CT can provide important diagnostic information. There is a high prevalence of CT abnormalities in non-small cell lung cancer that do not show lSF-FDG .uptake, but small proportion of which has clinical significance. Diagnostic CT should be done to get more significant information in PET/CT interpretation.