CT能谱成像在鉴别肝癌和局灶性结节增生中的价值

Values of spectral CT imaging in differential diagnosis of hepatocellular carcinoma and focal nodular hyperplasia

目的探讨CT能谱多参数成像在鉴别肝癌和局灶性结节增生（FNH）中的应用价值。方法回顾性分析48例肝脏占位病变患者（肝癌32例、FNH16例），均行64层能谱CT的能谱扫描模式（GSI）扫描，获得动脉期和门静脉期的能谱系列图像。测量病灶、正常肝组织和腹主动脉的能谱参数，并计算不同能量水平下病灶-肝脏对比噪声比（CNR）、标准化碘浓度（NIC）、病灶与正常肝组织碘浓度比值（LNR）、病灶动脉期和门脉期碘浓度的差异（ICD），对2组间上述测量指标进行两样本t检验和ROC曲线分析。结果肝癌和FNH在不同能量水平下的CNR呈现出一定的规律性。总的来说，CNR随着单光子能量的增加而减小，但在部分能量点除外。肝癌和FNH的动脉期最佳CNR分别为3．59±2．13、8．29±2．65，门脉期最佳CNR分别为1．80±0．42、1．06±0．34；肝癌和FNH动脉期NIC分别为0．25±0．08、0．42±0．22，门脉期NIC分别为0．52±0．14、0．86±0．18；动脉期LNR分别为2．97±0．50、6．15±0．97，门脉期LNR值分别为0．99±0．19、1．22±0．26；动脉期和门静脉期ICD值分别为（0．35±0．14）、（1．17±0．28）g／L。肝癌的动脉期和门脉期的NIC、LNR和ICD值均低于FNH，差异均有统计学意义（NIC比较t值分别为-3．196、-6．518，LNR比较t值分别为-12．911、-3．260、ICD比较t值为-2．754，P值均〈0．05）。动脉期LNR鉴别肝癌和FNH的敏感度和特异度最高，均为100％。结论CT能谱成像的定量分析对肝癌和FNH的检出和鉴别诊断有较大价值，能提高检出效能和诊断准确性。

Objective To explore the application value of spectral CT multi-parameter imaging in the differential diagnosis of hepatocellular carcinoma（HCC） and focal nodular hyperplasia （FNH）. Methods Forty-eight patients with hepatic lesions underwent gemstone spectral imaging （GSI） scans, including 32 HCC and 16 FNH,to obtain spectral serial images for the arterial phase and portal venous phase （PVP）. The spectral parameters of lesions, normal hepatic tissue and the aorta were measured. Then, the lesion-liver contrast-to-noise ratio （CNR） in the different energy levels, normalized iodine concentration （NIC）, the lesion-normal parenehyma iodine concentration ratio （LNR） and iodine concentration difference （ICD） between the arterial phase and the portal venous phase were calculated. The above measurement results were analyzed with two samples t test and ROC curve. Results The CNR of HCC and FNH in the different energy levels showed a certain regularity. In general, with the single photon energy increased, the CNR decreased except for some energy points. For HCC and FNH,the optimal CNR were 3.59 ±2. 13 and 8.29 ± 2. 65, respectively, during the arterial phase and 1.80 ± 0. 42 and 1.06 ± 0. 34, respectively, during the portal venous phase. The NIC were 0. 25 ± 0. 08 and 0. 42 ± 0. 22, respectively, during the arterial phase and 0. 52 ± 0. 14 and 0. 86 ± 0. 18,respectively, during the portal venous phase. The LNR were 2. 97 ± 0. 50 and 6. 15 ± 0. 97,respectively, during the arterial phase and 0. 99 ± 0. 19 and 1.22 ± 0. 26, respectively, during the portal venous phase. The ICD were （0. 35 ±0. 14） and （ 1.17 ±0. 28） g/L,respectively. The NIC,LNR and ICD for HCC were less than FNH during the arterial phase and the portal venous phase. There were significant differences in NIC （t = -3.196, the arterial phase; t = -6.518, the portal venous phase） , LNR （ t = - 12. 911, the arterial phase ; t = - 3. 260, the portal venous phase）, and ICD （ t = - 2. 754） between HCC and FNH （P 〈 0.05 ）. LNR in the arterial phase had the highest sensitivity and specificity of 100% and 100% in differentiating HCC from FNH. Conclusion The use of spectral CT with the quantitative analysis of iodine concentration might be helpful for increasing the efficiency of the detection and accuracy of diagnosis of HCC and FNH.