ROC曲线比较全身PET/CT和全身CT平扫对血清肿瘤标志物升高患者恶性肿瘤的检出效能

Compare the efficacy of whole body PET/CT with whole body CT scan for detecting malignant tumor in patients with elevated serum tumor markers by ROC curve

目的比较全身18F-FDGPET/CT和全身CT平扫对血清肿瘤标志物升高患者恶性肿瘤的检出效能。方法收集笔者所在医院2009年12月～2011年3月行全身PET/CT检查并伴有检查前2周内血清肿瘤标志物异常升高的患者30例。全身PET/CT显像和全身CT平扫均按5分法进行评分,并将血清肿瘤标志物测量值除以正常上限值以实现归一化处理。以病理诊断或临床随访为"金标准",绘制全身PET/CT和全身CT显像评分的ROC曲线,计算二者曲线下面积,并比较其差异是否具有统计学意义。将显像评分合并成两类:阴性(0、1、2分)和阳性(3、4分),分别计算全身PET/CT和全身CT相对于金标准的灵敏度、特异性、准确性、阳性预测值和阴性预测值。结果全身PET/CT及全身CT显像评分相对于金标准的ROC曲线下面积AUC(95%可信区间)分别为0.962(0.821～0.995)和0.917(0.757～0.985),二者差异无统计学意义(P=0.599)。二者的灵敏度均为80.00%(8/10),特异性均为100.00%(20/20),准确性均为93.33%(28/30),阳性预测值100.00%(8/8),阴性预测值均为90.90%(20/22)。结论全身PET/CT和全身CT平扫在预测肿瘤标志物升高患者是否存在恶性肿瘤病变方面无明显差异。

Objective To compare the whole body 18 F-FDG PET/CT with whole body CT scan for detecting malignant tumor in patients with elevated serum tumor markers. Methods 30 cases undergoing whole-body PET/CT and with elevated serum tumor markers were included. All PET/CT and CT images were scored according to the following criteria. And the normalization of serum tumor markers was performed. Using the pathology or clinical follow-up as the gold standard, the ROC curve of whole body PET/CT and whole body CT scan were drawn, the area under the curve （AUC） were calculated, and the difference between both AUC were compared. Imaging scores were then combined into two categories： negative （0,1,2） and positive （3,4）. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PET/CT and CT relative to the gold standard were calculated. Results The AUC（95% confidence interval） of the whole body PET/CT and whole body CT scan were 0.962（0.821-0.995） and 0.917（0.757-0.985） respectively, and the difference between them was not statistically significant （P=0.599）. Both sensitivity were 80.00% （8/10）, specificity were 100.00% （20/20）, accuracy were 93.33% （28/30）, positive predictive value were 100.00% （8/8）, negative predictive value were 90.90% （20/22）. Conclusion There was no significant difference between whole body PET/CT and whole body CT scan for detecting malignant tumor in patients with elevated serum tumor markers.