18F-FDG PET-CT CT 在诊断乳腺癌腋窝淋巴结转移状态的对比研究*

目的:通过与CT对比，探讨18F-FDG PET-CT 在诊断乳腺癌患者腋窝淋巴结转移中的价值。方法:回顾性分析22例行乳腺癌改良根治术患者的术前18F-FDG PET-CT 、CT图像。在CT图像上分别以淋巴结最短径>0.5cm（A 标准）、最短径≥1.0cm（B 标准）及最长径≥1.0cm（C 标准）为判定淋巴结转移的标准；在PET-CT 图像上，分别以目测腋窝淋巴结出现18F-FDG 异常放射性浓聚为判定淋巴结阳性的标准（D 标准）及半定量分析法异常放射性浓聚灶最大标准化摄取值（maximum standard uptake value ，SUV max）≥1.0 为判定淋巴结转移标准（E 标准）。 以术后病理为金标准，比较不同影像方法诊断腋窝淋巴结转移状态的价值。结果:乳腺癌患者腋窝阳性与阴性淋巴结在大小及SUV max 方面的差异均具有统计学意义。不同诊断标准中，以PET-CT 的总体诊断准确率及与病理吻合度Kappa 值最高，其中A 标准灵敏度最高（59.3%）而特异度最低（83.5%）；B 标准特异度和阳性预测值最高（分别为98.2% 、72.7%），而灵敏度和阴性预测值最低（27.1% 、88.4%）；C 标准各项诊断指标相对较差，无突出项；PET-CT 图像目测与半定量诊断结果相同，其诊断准确性（90.1%）、阴性预测值（92.5%）均优于单独CT诊断，且与病理诊断吻合度较好（Kappa 值为0.57），在诊断灵敏度（55.9%）、特异度（96.1%）及阳性预测值（71.7%）方面与单独CT比较也具较高诊断价值，阳性组SUV max 较阴性组明显为高，二者差异有统计学意义（P=0.000）。 不同影像方法在诊断腋窝淋巴结转移时差异有统计学意义（P<0.05）。 结论:18F-FDG PET-CT 是一种直观有效的评价乳腺癌腋窝淋巴结转移状态的方法。 

A Comparative Study of ~(18)F-FDG PET/CT and CT Imaging in Detection of Axillary Lymph Node Status of Breast Cancer

Objective:To investigate the value of ~(18)F-fluorodeoxyglucose (FDG) PET-CT imaging in detecting axillary lymph node status of breast cancer, in comparison with CT imaging.Methods:A total of 22 patients treated with routine modified radical mastectomy who underwent ~(18)F-FDG PET-CT imaging preoperatively were recruited in this retrospective study.PET-CT and CT images were reviewed.In CT imaging,the axillary lymph nodes were considered positive when the shortest diameter was longer than 0.5cm (criterion A) or longer than or equal to 1.0cm (criterion B) or the longest diameter was longer than or equal to 1.0 cm (criterion C),respectively.In PET-CT imaging,the axillary lymph nodes were considered positive when abnormal ~(18)F-FDG uptake(criterion D)was seen or the maximum standardized uptake value(SUV_(max))was larger than or equal to 1.0 for semiquantitative analysis (criterion E).All of the results were compared with histopathological results,and the diagnostic parameters of different diagnostic criteria were compared with each other.Results:There were statistical significances in the size and SUVmax in different diagnostic criteria between positive and negative axillary lymph nodes.PET-CT had the highest diagnostic accuracy and kappa value.Criterion A had the highest sensitivity(59.3%)and the lowest specificity(83.5%).Criterion B had the highest specificity(98.2%) and positive predictive value(PPV,72.7%)and the lowest sensitivity (27.1%) and negative predictive value (NPV, 8.4%). For criterion C, none of the diagnostic param-eters was of great value. For PET-CT, the results of visual assessment (criterion D) and semiquantitative analysis (criterion E) were identical and the accuracy (90.1%) and NPV (92.5%) were superior to those of CT; and the consistency with histo-pathological results was satisfacory (kappa value 0.57). The sensitivity (55.9%), specificity (96.1%) and PPV (71.7%) of PET-CT were higher than those of CT in detecting positive axillary lymph nodes. The SUVmax of metastatic lymph nodes was higher than that of lymph nodes with no metastasis, with a significant difference (P=0.000). Conclusion: ~(18)F-FDG PET-CT was an effective and intuitive method for detecting axillary lymph node status of breast cancer patients.