能谱CT定量分析在鉴别肝癌和肝脓肿中的价值

Value of spectral CT-based quantitative analysis in differential diagnosis of liver cancer and liver abscess

目的探讨能谱CT定量分析在鉴别肝癌和肝脓肿中的应用价值。方法对70例肝脏占位病变患者，其中肝癌45例、肝脓肿25例，均行能谱CT扫描，获得动脉期和门静脉期的能谱系列图像。分别测量动脉期和门静脉期病灶实性成分、坏死囊变区、正常肝组织和腹主动脉的碘浓度和水浓度，并计算标准化碘浓度（NIC）和病灶与正常肝组织碘浓度比值（LNR），对两组间上述定量指标进行两样本t检验和ROC曲线分析。结果肝癌实性成分的动脉期NIC[（0．15±0．06）mg／m1]和LNR（2．78±0．65）均〉肝脓肿[（0．14±0．02）mg／ml和1．45±0．88]，两者NIC的差异无统计学意义（P〉0．05），而LNR的差异有统计学意义（P〈0．001）。肝脓肿实性成分门静脉期的NIC[（0．65±0．08）mg／ml]和LNR（1．22±0．23）均〉肝癌[（0．52±0．08）mg／ml和0．95±0．15]，两者NIC和LNR的差异均有统计学意义（P≤0．001）。肝癌和肝脓肿坏死囊变区的动脉期的NIC和门静脉期的NIC、LNR的差异均无统计学意义（P〉0．05）。鉴别肝癌和肝脓肿的最佳能谱定量值是动脉期LNR值，其阈值1．53鉴别两者的敏感度和特异度分别为100％和92％。结论能谱CT成像的碘物质定量分析对肝癌和肝脓肿的鉴别诊断有一定价值，能提高诊断准确性。

Objective To investigate the value of spectral CT-based quantitative analysis in the differential diagnosis of liver cancer and liver abscess. Methods A total of 70 patients with space-occupying lesions in the liver （45 with liver cancer and 25 with liver abscess） underwent spectral CT scans to obtain spectral images in the arterial phase and portal venous phase. The solid constituents of lesions and the iodine and water concentrations in necrotic or cystic parts of lesions, normal hepatic tissue, and abdominal aorta in the arterial phase and portal venous phase were measured, and the normalized iodine concentration （NIC） and lesion-to-normal hepatic tissue ratio （LNR） of iodine concentration were calculated. The two samples t-test and the receiver operating characteristic （ROC） curve analysis were performed for the quantitative indices above. Results The patients with liver cancer had higher NIC and LNR in solid constituents in the arterial phase than those with liver abscess （NIC： 0.15~0.06 mg/ml vs 0.14±0.02 mg/ml, P 〉 0.05; LNR： 2.78±0.65 vs 1.45±0.88, P 〈 0.001）. The patients with liver abscess had significantly higher NIC and LNR in solid constituents in the portal venous phase than those with liver cancer （NIC： 0.65±0.08 mg/ml vs 0.52±0.08 mg/ml, P ≤0.001; LNR： 1.22±0.23 vs 0.95±0,15, P ≤ 0.001）. There were no significant differences in NIC in the arterial phase or NIC and LNR in the portal venous phase in necrotic or cystic parts of lesions between the patients with liver cancer and liver abscess （P 〉 0.05）. The optimal quantitative value for the differential diagnosis of liver cancer and liver abscess was LNR in arterial phase, and the cut-off value of 1,53 had a sensitivity of 100% and a specificity of 92%. Conclusion Quantitative iodine concentration analysis in spectral CT imaging has a certain value in the differential diagnosis of liver cancer and liver abscess and can improve the accuracy of diagnosis.