动态^(18)F-FDG PET定量分析用于骨病变鉴别诊断

Quantitative evaluation of skeletal tumors with dynamic ^(18)F-FDG PET

目的 评价18F 脱氧葡萄糖 (FDG)PET在骨骼病变中的诊断价值。方法 研究对象为40例原发性骨骼病变患者。所有患者在注射示踪剂后立即开始动态PET采集 ,持续 6 0min。对动态PET图像进行半定量分析 ,分别计算平均和最大标准摄取值 (SUVaver和SUVmax) ,病灶SUV/肌肉SUV比值 (T/M) ,病灶 6 0minSUV/ 30minSUV比值 (SUVaver 60 /3 0min和SUVmax 60 /3 0min)等。采用Patlak作图分析法对动态图像数据进行拟合计算 ,得出摄入常数 (Ki) ,计算FDG代谢率 (MRFDG)。根据接受器工作特性曲线 (ROC)确定各定量指标的诊断阈值 ,并比较其鉴别良恶性病变的灵敏度和特异性。结果 经病理检查证实恶性病变 2 1例 ,良性病变 19例。恶性病变的MRFDG和SUV值高于良性病变 ,但各种指标的数值分布均存在交叉重叠。SUVaver与MRFDG呈正相关 (r=0 6 7)。以SUV值≥ 1 8作为阈值时 ,鉴别良恶性病变的灵敏度和特异性分别为 85 0 %和 82 4% ,以MRFDG(1 1)为阈值时的灵敏度 (82 4% )与SUV相近 ,而特异性 (92 9% )较高。同时采用SUV(1 8)和SUVaver 60 /3 0min(1 1)作为鉴别标准时 ,较之单独采用SUV特异性可改善为 93 3% ,灵敏度略有降低 (81 3% )。结论 骨骼良恶性病变之间存在葡萄糖代谢率差异。单用静态FDGPET获取SUV值不能很好鉴?

Objective To evaluate bone lesions using fluorodeoxyglucose (FDG) PET and explore if dynamic and quantitative PET data may help to differentiate benign lesions from malignant masses. Methods A group of forty patients with primary bone lesions were studied. The final diagnosis was confirmed with histopathology. A dynamic acquisition of FDG PET with the duration over 60 min was undertaken in all subjects. From the dynamic PET images the indexes such as average and maximal standardized uptake value ( SUV ), tumor SUV-to-muscle SUV ratios ( T/M ), and SUV at 60 min-to- SUV at 30 min ratio ( SUV aver 60/30 min and SUV max 60/30 min) were produced. Patlak graphical analysis were used to obtain influx constant (K i) and metabolic rate of FDG (MRFDG) was thus calculated. Based on the receiver operation characteristic curve the sensitivity and specificity for each parameter in differentiation between malignant and benign lesions was evaluated. Results The histologic results revealed there were 21 cases with malignant tumors and 19 with benign lesions in this group. The MRFDG and SUV indexes in malignant lesions were significantly higher than those in benign lesions. However, each index showed a considerable overlap between benign and malignant type. Average SUV positively correlated with MRFDG (r=0.67).When use of a 1.8 cutoff for average SUV, the sensitivity and specificity for discrimination of malignancy from benignity were 85.0% and 82.4%, respectively. MRFDG showed a similar sensitivity (82.4%) and a better specificity (92.9%). When evaluated with a cutoff from the combination of average SUV (1.8) and SUV aver 60/30 min (1.1), the specificity was improved to 93.3% with a small reduction of sensitivity (81.3%) compared with using SUV exclusively. Conclusions The results indicate that detectable difference in glucose metabolism exists between malignant and benign skeletal lesions. It may not be feasible to use exclusively the static FDG uptake indexes to achieve a sufficient differentiation between benign and malignant lesions. Quantitative dynamic imaging may provide more helpful information, but a conclusive description may not be given from the pr-esent study. It may be an alternative and interesting approach to use the uptake indexes retrieved from dynamic imaging to evaluate bone lesions.