弥散加权成像联合普美显磁共振成像在肝癌TACE术后疗效评估中的应用

The application of diffusion weighted imaging combined with Gd-EOB-DTPA MRI in evaluating the curative efficacy of TACE for hepatocellular carcinoma

目的探讨弥散加权成像(DWI)联合普美显(Gd-EOB-DTPA)MR成像在肝癌TACE后疗效评估中的应用价值。方法 20例确诊肝癌患者于TACE术前、术后行上腹部DWI及Gd-EOB-DTPA动态增强扫描,定性分析TACE术前、术后肝癌活性成分,坏死和复发转移情况。测量TACE术前、术后病灶的表观弥散系数(ADC)值和信号值(signal intensity,SI),并计算术前、术后病灶的动脉期对比增强比(CER)和动脉期的信号比(SIR),对定量参数ADC、CER和SIR值进行配对样本t检验。结果本组20例患者共检出肝癌病灶45个。TACE术后瘤灶内残存及复发部分在DWI图像上呈高信号,ADC图上信号低于正常肝组织,动脉期可见明显强化,门脉期及平衡期强化减退,肝胆特异期呈明显低信号;瘤灶内坏死部分DWI序列呈低信号,ADC图上为高信号,增强扫描后无强化,肝胆特异期亦呈明显低信号。肝癌病灶术前、术后ADC值分别为(1.52±0.16)×10^(-3)mm^2/s和(1.70±0.28)×10^(-3) mm^2/s,术后肝癌病灶的ADC值普遍升高,两者的差异有统计学意义。肝癌TACE术后的CER_(动脉期)和SIR_(动脉期)值减小,与术前相比,两者的差异有统计学意义。有效组肝癌病灶的术后ADC值大于无效组,而其CER_(动脉期)和SIR_(动脉期)值均小于无效组,两者术后的ADC、CER_(动脉期)和SIR_(动脉期)值的差异均有统计学意义。结论联合应用DWI和GdEOB-DTPA增强MR成像能有效评估肝癌TACE术后病灶存活及坏死情况,检出早期复发、新发灶及转移灶,对制定下一步治疗方案具有重要意义。

Objective To investigate the clinical application of diffusion weighted imaging （DWI） combined with Gd-EOB-DTPA MRI in evaluating the therapeutic efficacy of transarterial chemoembolization （TACE） for hepatocellular carcinoma （HCC）. Methods Both DWI and Gd-EOB-DTPA-enhanced dynamic MR scan of upper abdomen were performed in 20 patients with confirmed HCC before and after TACE. The pre-TACE and post-TACE active components, necrosis, recurrence and metastasis of HCC were qualitatively analyzed. The pre-TACE and post-TACE apparent diffusion coefficient （ADC） as well as the signal intensity （SI） of HCC were measured, and the pre-TACE and post-TACE contrast enhancement ratio （CER） as well as signal intensity ratio （SIR） of HCC were calculated. ADC, CER and SIR values were analyzed by using paired sample t test. Results In this group of 20 patients, a total of 45 HCC lesions were detected. After TACE the residual and recurred HCC tissues presented as hyper-intensity signals on DWI images and as hypo-intensity signals （lower than those of normal liver tissues） on ADC maps, which showed obvious enhancement in thearterial phase （AP） with a relatively quick washout in both the portal venous phase （PP） and equilibrium phase （EP） and which were characterized by remarkable hypo- intensity signals in the hepatobiliary phase （HP）. The necrotic tissues within HCC lesions were manifested as hypo-intensity signals on DWI images and as hyper-intensity signals on ADC maps, which showed no enhancement on enhanced images and were also presented as obvious hypo-intensity signals in HP. The pre- TACE and post-TACE ADC values of HCC lesions were （1.52：tO.16）xlO-3 mm＂/s and （1.70_＋0.28）x10-3 mm%, respectively, which showed that the post- TACE ADC values of HCC lesions were generally increased, and the differences were statistically significant. The post-TACE CERAP and SIRAP values were obviously lower than the pre-TACE ones, and the differences were statistically significant. The post-TACE ADC values of HCC lesions in the effective group were higher than those in the ineffective group, while the post-TACE CERAP and SIRAP values of the effective group were lower than those of the ineffective group, and statistically significant differences in post-TACE ADC, CERAP and SIRAP values existed between the two groups. Conclusion Combination use of DWI and Gd- EOB-DTPA-enhanced MRI can effectively assess the survival and necrosis of HCC lesions after TACE, and can reliably detect early recurrence, newly-developed tumors and metastases, which are of great significance for the making of the further treatment plan.