ADC直方图早期监测直结肠癌肝转移瘤化疗敏感性的价值

ADC value in MR diffusion weighted imaging for monitoring early response in colorectal cancer patients with liver metastases undergoing chemotherapy

目的探讨表观扩散系数(ADC)直方图早期监测直结肠癌肝转移瘤化疗敏感性的价值。方法对42例直结肠癌肝转移瘤患者进行常规磁共振平扫、增强及DWI检查,分别测量化疗前、化疗第1周期后及化疗完成后靶病灶的最大径(LD)和ADC值,计算LD值早期变化率(ΔLD)及ADC值早期变化率(ΔADC)。依据实体肿瘤疗效评价标准(RECIST)分为低敏感组和高敏感组,比较两组靶病灶化疗早期监测指标的差异,并以直方图显示ADC值变化。ROC曲线分析ADC值早期预测转移瘤化疗的灵敏度。结果共确诊65个肝转移瘤靶病灶,其中高敏感组30个和低敏感组35个。化疗前和化疗第1周期后,高敏感组与低敏感组的LD值和ΔLD值均无统计学意义(均P>0.05)。化疗前高敏感组和低敏感组的ADC值分别为(1.303±0.062)×10^-3mm^2/s、(1.340±0.065)×10^-3mm^2/s,化疗第1周期后分别为(1.394±0.079)×10^-3mm^2/s、(1.330±0.088)×10^-3mm^2/s,高敏感组ADC值明显升高(P<0.05),而低敏感组无明显变化(P>0.05);高敏感组ΔADC高于低敏感组,差异有统计学意义(P<0.01),直方图显示峰值明显右移。ΔADC早期预测化疗疗效的灵敏度、特异度和AUC分别为90.0%、77.14%和0.891。结论ΔADC可作为预测肝转移瘤对化疗敏感性的定量指标,ADC直方图有助于直观显示化疗疗效变化。

Objective To investigate the value of apparent diffusion coefficient(ADC)histogram on 3.0 T MR diffusion weighted imaging(DWI)for monitoring the early chemotherapy response in colorectal cancer patients with liver metastases.Methods Forty two colorectal cancer patients with liver metastases receiving chemotherapy underwent MRI examination including plain and enhanced scan,and DWI.The longest diameter(LD)and ADC values were measured pre-chemotherapy,at the first chemotherapy cycle and post-chemotherapy.The target lesions were grouped into the hypersensitivity and hyposensitivity based on response evaluation criteria in solid tumors(RECIST)and the change of ADC histogram was demonstrated.The receiver operating characteristic(ROC)curve analysis was performed for evaluation of the sensitivity,specificity and Az value.Results Sixty five target lesions were confirmed including 30 lesions in the hypersensitivity group and 35 lesions in the hyposensitivity group.The difference of the LD andΔLD values were not significant between the hypersensitivity group and the hyposensitivity group pre-chemotherapy and at the first cycle chemotherapy.The ADC values of the hypersensitivity and hyposensitivity groups were(1.303±0.062)×10^-3mm^2/s,(1.340±0.065)×10^-3mm^2/s pre-chemotherapy,and(1.394±0.079)×10^-3mm^2/s,(1.330±0.088)×10^-3mm^2/s at the first cycle chemotherapy,respectively.The ADC value of the hypersensitivity group was significantly higher than that at first cycle(P<0.05),but the ADC value of the hyposensitivity group was not significantly changed(P>0.05).The ADC histogram showed the peak shifted significantly to the right.TheΔADC value of the hypersensitivity group was higher than that of the hyposensitivity group at the first cycle(P<0.01).ROC curve analysis showed the Az value ofΔADC was the highest(Az=0.891),the sensitivity was 90%and specificity was 77.14%for early response assessment.Conclusion TheΔADC value in DWI may be used as an indicator in predicting chemotherapy sensitivity,and the ADC histogram analysis is helpful for early response assessment of colorectal cancer patients with liver metastases undergoing chemotherapy.