18F-FDG PET/CT对不同大小孤立性肺结节的诊断价值

目的 评价18F-脱氧葡萄糖(FDG) PET/CT对不同大小范围孤立性肺结节(SPN)良恶性鉴别诊断的价值.方法 从全国拥有PET/CT的10家医院筛选出已经获得病理学检查结果的SPN病例,收集诊断CT、PET/CT和病理检查结果以及标准摄取值(SUV)、结节大小等资料.诊断CT、PET/CT结果为肺癌、肺癌可能性大、肺癌可能者为阳性;结果为良性病变、良性可能性大、良性可能者为阴性;难以确定阳性和阴性者为不确定.采用SPSS 10.0软件对资料进行分析.结果 120个(120例)SPN中良性结节28个,恶性结节92个.直径或(长径+短径)/2≤1.0cm的结节17个,恶性病变9个;1.1～2.0cm 57个,恶性病变占75.44%;2.1～3.0cm 46个,恶性病变占86.96%.28个良性结节SUV最大值(SUVmax)的平均值为4.5±4.9, SUV平均值(SUVmean)的平均值为2.9±3.6;92个恶性结节SUVmax平均值为6.7±4.2, SUVmean平均值为4.9±3.6;良性结节的SUV显著低于恶性结节的SUV.无论良性还是恶性结节,随着结节的增大,SUV升高.诊断CT对结节良恶性鉴别的灵敏度为78.26%,特异性3/8,准确性72.22%; PET/CT灵敏度为94.51%,特异性64.00%,准确性87.93%.结论 18F-FDG PET/CT在SPN鉴别诊断中具有较高的灵敏度、特异性和准确性,优于诊断CT;结节大小是判断SPN良恶性的重要指标,直径或(长径+短径)/2＞2.0cm的结节,恶性可能性约为87%; SUV可以作为鉴别诊断的依据,但鉴于良性结节SUVmean的平均值为2.9±3.6,界值2.5仅供参考,尤其是对于≤1.0cm的结节.

18F-FDG PET/CT in differential diagnosis of solitary pulmonary nodule with different size

Objective The differential diagnosis of solitary pulmonary nodule (SPN) is not an easy task for the thoracic imaging. The aim of this study was to assess the value of 18F-fluorodeoxyglucose (FDG) PET/CT in helping the differential diagnosis of benign and malignant SPN. Methods SPN patients with known pathological results underwent PET/CT imaging in 10 different hospitals. The results of CT, PET/CT, pathology, quantitative data [standardized uptake value (SUV), size of nodules] were collected. The characteristic wordings on the CT and PET/CT reports that were considered to be positive included lung cancer, highly possible lung cancer and possible lung cancer. Those of the negative findings included benign lesion, highly possible benign lesion and possible benign lesion. The results, which were difficult to be judged as positive or negative, were considered to be indeterminate. The analysis of the data was carried out using SPSS 10.0. Results There were 120 SPNs included for analysis: 28 benign and 92 malignant nodules. When the lesion size was≤ 1.0cm, the percentage of malignant lesions was 52.94%(9/17). When the nodule size ranged from 1.1 to 2.0cm and from 2.1 to 3.0cm, the percentage rose to 75.44%(43/57) and 86.96%(40/46), respectively. The average of individual lesion SUVmax was 4.5±4.9 and SUVmean was 2.9±3.6 in 28 benign nodules. The corresponding SUVmax and SUVmean for the 92 malignant lesions were 6.7±4.2 and 4.9±3.6, respectively. The SUV of benign nodules was significantly lower than that of malignant nodules. The SUV increased as the size of nodules increased regardless of benignity or malignancy. The sensitivity, specificity and accuracy of CT and PET/CT were 78.26%,3/8,72.22% and 94.51%,64.00%,87.93% respectively. Conclusions 18F-FDG PET/CT is superior to CT with higher sensitivity, specificity and accuracy for differentiating benign from malignant SPNs. The size of SPN is an important parameter for differentiation. The possibility of malignancy was about 87% when the nodule is greater than 2.0cm. SUV can be helpful but the conventional threshold value of 2.5 was only a rough reference, because the SUVmean statistics of the benign nodules (2.9±3.6) were highly variable, particularly with the subcentimeter nodules.