符合线路SPECT双时相显像鉴别良恶性病变的诊断效能评价

目的探讨半定量分析及受试者工作特性(ROC)曲线法在18F-FDG双探头符合线路SPECT(SPECT/PET)双时相显像鉴别良恶性病变的临床价值.方法30例病变性质不明患者进行18F-FDG SPECT/PET双时相显像,早期显像在注射FDG后1 h进行,延迟显像(2组)分别在注药后3.5和4.5 h,结果均经病理证实或临床随访确诊.对双时相显像结果采用阅片目测定性和半定量方法分析,计算2次显像每个病灶感兴趣区(ROI)与同一平面对侧正常组织或周围正常组织的放射性摄取率之比(T/NT)及滞留指数(RI).应用ROC曲线计算曲线下面积(AUC)评价早期显像、延迟显像和RI的诊断效能.结果30例患者(1例患者行2次双时相显像)共检出48个病灶(恶性病变30个,良性病变18个),29个病灶为真阳性,15个病灶为真阴性,3个假阳性和1个假阴性.定性分析双时相显像的灵敏度96.7%,特异性83.3%,准确率91.7%,阳性预测值(PPV)90.6%,阴性预测值(NPV)93.8%.SPECT/PET早期显像和CT的灵敏度、特异性、准确率、PPV、NPV分别为93.3%、72.2%、85.4%、84.8%、86.7%与76.9%、57.1%、70%、76.9%、57.1%.所有恶性病变(除l例假阴性病变外)延迟显像T/NT均明显升高(t=-3.071,P＜0.01),而良性病变延迟显像与早期显像T/NT无显著性差异(t=0.398,P=0.695).ROC曲线结果表明,RI明显优于早期显像及延迟显像.与早期显像和CT相比,双时相显像结合RI分析的灵敏性、特异性、准确性、PPV、NPV,分别为96.7%、88.9%、93.8%、93.5%、94.1%.结论 18F-FDGSPECT/PET双时相显像结果分析判断结合半定量和ROC曲线法分析有助于提高良、恶病变诊断的特异性和准确率.

Diagnostic ability of dual-phase 18F-fluoro-2-deoxy-D-glucose SPECT/PET for distinguishing benign and malignant lesions

Objective To evaluate the clinical diagnostic value of dual-phase 18 F-FDG SPECT/PET using semiquantitative analysis and receiver operating characteristic (ROC) curve method for distinguishing the benign and malignant lesions. Methods Thirty patients with unknown lesions were enrolled in this study. All patients underwent dual-phase 18 F-FDG SPECT/PET. The early images were obtained at 60 min after injection. And the patients were divided into 2 groups, one received delayed scans at 210 min after 18 F-FDG injection and the other at 270 min. Lesion status was determined by pathologic findings or by clinical follow-up. The results were analyzed by qualitative and semiquantitative methods. For all lesions, the ratio of tumor to no tumor (T/NT) activity and the retention index (RI) of dual-phase images were calculated. ROC with calculation of area under the curve (AUC) was used to evaluate diagnostic ability of early imaging, delayed imaging and RI, respectively. Results Forty-eight lesions (30 malignant and 18 benign verified by pathologic findings or clinical follow-up) of 30 patients were detected by dual-phase imaging, in which there were 29 true positive results, 15 true negative, 3 false positive and 1 false negative. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of dual-phase imaging were 96.7%, 83.3%, 91.6%, 90.6%, and 93.8%, respectively. Those of early imaging and CT were 93.3%, 72.2%, 85.4%, 84.8%, 86.7% and 76.9%, 57.1%, 70.0%, 76.9%, 57.1%, respectively. The ratio of T/NT in all malignant lesions(except 1 false negative case) in delayed imaging were significantly increased (t= -3.071 ,P<0.01). However, there were no statistical differences in the ratio of T/NT in benign lesions (t=0.398,P= 0.695 ) between early and delayed imaging. The results of ROC curve shows that RI was significantly superior to early and delayed imaging. Combining RI with dual-phase imaging provided a higher diagnostic sensitivity, specificity, accuracy, PPV and NPV (96.7%, 88.9%, 93.8%, 93.5%, 94.1%) than those of the early imaging and CT. Conclusion Dual-phase FDG-SPECT/PET provides benefit for differentiating benign from malignant lesions. And combined dual-phase imaging with ROC analytic method will improve the diagnostic specificity and accuracy.