能谱及灌注CT成像鉴别诊断周围型肺癌和局灶性机化性肺炎的对比研究

A Comparison of Spectral and Perfusion CT Imaging in Differentiating Peripheral Lung Cancer from Focal Organizing Pneumonia

目的比较能谱及灌注CT成像在鉴别周围型肺癌(PLC)和局灶性机化性肺炎(FOP)中的准确度。资料与方法前瞻性收集临床怀疑为肺恶性肿瘤患者,行胸部一站式能谱联合灌注扫描并经病理证实,最终纳入PLC患者45例、FOP患者33例。测量两组病灶在动脉期和静脉期的能谱参数,包括CT_(40 keV)值、CT_(70 keV)值、CT_(100 keV)值、碘(水)浓度(IC)、水(碘)浓度(WC)、有效原子序数(Zeff),并计算能谱曲线斜率(K_(70 keV))。同时测量两组病灶的灌注参数,包括血容量(BV)、血流量(BF)、平均通过时间(MTT)和表面通透性(PS)。比较两组病灶的能谱参数及灌注参数之间的差异。绘制受试者工作特征(ROC)曲线,比较两组病灶能谱参数及灌注参数的曲线下面积(AUC)、敏感度、特异度及准确度。结果在动脉期和静脉期,FOP组的能谱参数CT_(40 keV)、CT_(70 keV)、能谱曲线K_(70 keV)、IC及Zeff大于PLC组,差异有统计学意义(t=-3.21、-2.57、-3.10、-3.06、-3.00,P均<0.05)。FOP组灌注参数BV、BF、MTT及PS低于PLC组,差异有统计学意义(t=3.28、2.56、4.58、2.43,P均<0.05)。双期能谱参数联合的ROC曲线下面积为0.89,大于灌注参数的0.80,其敏感度、特异度和准确度分别为0.86、0.83和0.84。结论与灌注CT成像相比,能谱CT成像鉴别PLC和FOP的准确度更高。

Purpose To compare the accuracy of spectral and perfusion CT imaging in the differential diagnosis of peripheral lung cancer(PLC)and focal organized pneumonia(FOP).Materials and Methods Patients with clinically suspected lung malignant tumors were prospectively collected and underwent one-stop chest spectral and perfusion scan,which was confirmed by pathology.Finally,45 patients with PLC and 33 patients with FOP were collected.The spectral parameters,including CT_(40 keV),CT_(70 keV),CT_(100 keV),iodine(water)concentration(IC),water(iodine)concentration(WC),effective atomic number(Zeff)of the lesions in the arterial and venous phases of the two groups were measured,and the slope of the energy spectrum curve(K_(70 keV))was also calculated.The perfusion parameters,including blood volume(BV),blood flow(BF),mean transit time(MTT)and permeability surface(PS)of the two groups were measured at the same time.The differences of spectral and perfusion parameters between the two groups were compared.Receiver operating characteristic(ROC)curve was generated to calculate and compared the area under the curve(AUC),sensitivity,specificity and accuracy of the spectral and perfusion parameters between the two groups.Results In the arterial phase and the venous phase,the spectral parameters CT_(40 keV),CT_(70 keV),spectral curve K_(70 keV),IC and Zeff of the FOP group were significantly greater than those of the PLC group(t=-3.21,-2.57,-3.10,-3.06,-3.00,respectively,all P<0.05).The perfusion parameters BV,BF,MTT and PS of the FOP group were significantly lower than those of the PLC group(t=3.28,2.56,4.58,2.43,respectively,all P<0.05).ROC curve analysis showed that the AUC of the combination of spectral parameters was 0.89,which was significantly larger than that of perfusion parameters 0.80,its sensitivity,specificity and accuracy were 0.86,0.83,0.84,respectively.Conclusion Compared with the perfusion CT imaging,spectral CT imaging has a high accuracy in distinguishing PLC from FOP.