能谱 CT 碘基图在鉴别中央型肺癌与继发阻塞性肺实变中的价值

目的：探讨能谱 CT 碘/水基物质图(以下简称为碘基图)对鉴别中央型肺癌与继发阻塞性肺实变的诊断价值。方法对25例经术后病理确诊为中央型肺癌合并阻塞性肺实变(阻塞性肺炎和阻塞性肺不张)的患者行宝石能谱常规 CT 平扫和能谱成像模式(GSI)双期增强扫描,增强扫描数据经 GSI viewer 生成各期常规 CT 图像和碘基图,由2位影像医师参照术后标本图片观察评价增强扫描所得到的4种图像对癌组织与阻塞性肺实变组织空间解剖关系分界的正确辨别率。结果平扫图像上肿瘤与阻塞性肺实变边界不清,增强扫描后肿瘤均呈轻、中度强化,而阻塞性肺实变组织多呈持续强化。增强扫描4种图像能够分辨肿瘤与实变肺组织边界的例数分别为：肺动脉期 CT 图像10例(40%),支气管动脉期 CT 图像16 例(64%),肺动脉期碘基图19例(76%),支气管动脉期碘基图23例(92%)。4种图像分辨能力存在差异(χ2=16.54,P <0.05)。两两比较,支气管动脉期碘基图可判断肿瘤范围的比率最高,优于其他3种图像(χ2=12.83、χ2=4.20、χ2=1.34,P <0.05)；肺动脉期碘基图与支气管动脉期 CT 图像之间差异无统计学意义(χ2=0.86,P >0.05),但却优于肺动脉期 CT 图像(χ2=6.65,P <0.05)。结论对于中央型肺癌并发支气管阻塞者,利用能谱 CT 碘基图,特别是支气管动脉期碘基图,能很好地显示肿瘤和阻塞性实变组织的部位、大小、分界等解剖关系,为临床分期及治疗提供更加精确的信息。

Differentiation of central lung cancer from obstructive pneumonia and atelectasis using spectral CT iodine-based material decomposition technique

Objective To explore the value of the spectral CT iodine-based material decomposition technique in differential diagnosis of central pulmonary carcinoma from obstructive pneumonia and atelectasis.Methods 25 cases with central pulmonary carcinoma complicating with obstructive pneumonia and atelectasis underwent CT plain scan and spectral contrast scan including pulmonary-arterial-phase (PAP) and bronchial-arterial-phase(BAP).Conventional CT images and iodine base images were generated in each phase by GSI viewer.The 4 groups of images differences between the tumor and the obstructive pneumonia and atelectasis were analyzed.Results The margin of the tumor was ill-defined in plain scan.The cases that showed difference between the tumor and the obstructive pneumonia and atelectasis in 4 groups of images were respectively as follows,10 in conventional CT images of PAP,1 6 in conventional CT images of BAP,1 9 in iodine base images of PAP,and 23 in iodine base images of BAP.The difference of the 4 groups was significant (χ2 =16.54,P<0.05).There was the highest accuracy in iodine base images of BAP in defining the tumor margin (χ2 = 12.83,χ2 = 4.20,χ2 =1.34,P <0.05). The accuracy between conventional CT images of BAP and iodine base images of PAP had no significant differences (χ2 =0.86,P >0.05),but were better than that of the conventional CT images of PAP(χ2 =6.65,P <0.05).Conclusion Spectral CT iodine-based material decomposition technique is helpful to improve subjective diagnosis of central pulmonary carcinoma complicating with obstructive pneumonia and atelectasis,especially in iodine base images of BAP,it can provide accurate information for clinical stage and treatment.