磁共振血氧水平依赖成像观察原发性肝细胞癌高强度聚焦超声治疗前后氧摄取变化特点

Blood oxygen level-dependent MRI in observation of oxygen-uptaking characteristics of primary hepatocellular carcinoma before and after high intensity focused ultrasound ablation

目的通过观察原发性肝细胞癌(HCC)高强度聚焦超声(HIFU)治疗前后氧摄取变化特点,探讨BOLD MRI评估HIFU治疗原发性HCC疗效的潜在价值。方法 16例原发性HCC患者于HIFU治疗前及治疗后2周内接受常规MRI、BOLD MRI及动态增强扫描。BOLD MRI采用梯度回波序列。将BOLD图像数据传输至工作站,采用R2*软件对图像进行后处理生成R2*图及T2*图。在病灶中心、周围正常肝组织以及背部肌肉设置ROI,测量R2*值、T2*值及信号强度(SI)。对3个ROI R2*值、T2*值及SI在HIFU治疗前后的差异进行比较。结果与治疗前比较,HCC R2*值在HIFU治疗后2周内明显升高[(34.91±4.14)Hz vs(29.80±4.55)Hz,t=-13.53,P<0.01)],而T2*值、SI值在HIFU治疗后2周内明显降低[(29.10±4.14)ms vs(34.93±6.84)ms,t=6.09,P<0.01;134.37±32.06 vs 428.31±67.45,t=16.28,P<0.01]。周围肝组织及背部肌肉R2*值、T2*值及SI值在HIFU治疗前后的无明显变化(P>0.05)。结论 BOLD MRI在评价原发性肝细胞癌缺氧及HIFU疗效方面有一定潜力。

Objective To investigate the potential value of BOLD MRI in evaluation of primary hepatocellular carcinoma（HCC） after high intensity focused ultrasound（HIFU） ablation by observing the characteristics of oxygenation before and after HIFU ablation.Methods Routine MRI,BOLD MRI and contrast-enhanced MRI were performed on 16 patients with primary HCC before and after HIFU ablation.Fast gradient echo sequence was used to acquire BOLD MRI.The data were transmitted to a workstation and post-processed with the R2＊ software to generate R2＊ map and T2＊ map.ROI was placed on the lesion,the peripheral liver tissue and the muscle of back.R2＊ value,T2＊ value and signal intensity（SI） in three ROIs before and after HIFU ablation were measured,and the differences were compared.Results Mean R2＊ value of primary HCC increased from（29.80±4.55）Hz before HIFU ablation to（34.91±4.14）Hz after HIFU ablation（t=-13.53,P〈0.01）.Mean T2＊ value of HCC decreased from（34.93±6.84）ms before HIFU ablation to（29.10±4.14）ms after HIFU ablation（t=6.09,P〈0.01）.Mean SI of HCC decreased from 428.31±67.45 before HIFU ablation to 134.37±32.06 after HIFU ablation（t=16.28,P〈0.01）.No significant difference of R2＊ value,T2＊ value and SI on peripheral liver tissue and muscle on back was found before and after HIFU ablation（P〉0.05）.Conclusion BOLD MRI has potential capability in evaluation on the hypoxia of primary HCC and therapeutic effect of HIFU ablation.