【作者】 任晓璇；

【导师】 杜端明；

【作者基本信息】 汕头大学 ， 影像医学与核医学， 2011， 硕士

【摘要】 目的:研究磁共振扩散加权成像(DW-MRI)在肝癌射频术后肿瘤残存/复发或新发病灶的早期诊断和射频消融灶各组织成分定量评价中的应用价值。材料与方法:对31例肝癌患者射频消融(RFA)术前及术后和20例正常对照组的DW-MRI资料进行分析,观察DWI对肝癌RFA术后病灶的显示情况及DWI和ADC图上感兴趣区域(ROI)的信号变化,在ADC图上测量RFA前病灶的ADC值和RFA后消融灶内不同组织的ADC值,并与病理或DSA图像对照,获得各组织成分的ADC界限值。结果:分析28例CT图像和31例RFA治疗前磁共振平扫+增强、DWI图像的敏感度、特异度、PPV和NPV,结果显示磁共振平扫+增强结合DWI的敏感度最高(100%)。31例患者的扫描结果显示b值选取600和800 s/mm~2的DWI图像显示肝癌病灶及消融灶信号较准确。31例患者的38个病灶RFA治疗前后均进行了MRI平扫、增强、DWI图像分析及ADC值测量。利用整体测量法和高低信号区测量法,在b值为800 s/mm~2的ADC图中测得肝癌病灶的ADC值与正常肝实质ADC值间的差异分别具有显著性(P<0.05);在b值为600和800 s/mm~2的ADC图测得肝癌病灶与周围肝组织、肝癌病灶与炎性反应组织以及肝癌病灶RFA术前与术后的ADC值间差异分别具有显著性(P<0.05);在b值为400 s/mm~2的ADC图测得肝癌病灶与周围肝组织、肝癌病灶与炎性反应组织以及肝癌病灶RFA术前与术后的ADC值间差异无显著性(P>0.05);在b值为400、600和800 s/mm~2的ADC图中测得RFA术后肝癌病灶与凝固坏死组织、肝癌病灶与液化坏死组织的ADC值间差异分别具有显著性(P<0.05)。结论:DWI发现肿瘤的敏感性较高,结合MRI应用可提高肝癌病灶的检出能力。在病灶显示清楚的前提下尽量选取b值为800 s/mm~2的ADC图测量所得的ADC值接近真实DC值。DWI结合ADC图可显示肿瘤与正常肝实质、炎性组织以及坏死组织之间的信号差异,并且每种组织具有较特定的ADC值范围,可定量评价RFA治疗的疗效。更多还原

【Abstract】 Objective: To evaluate the clinic value of DW-MRI in the early diagnosis of residual lesions or new lesions and the quantitative evaluation of DWI for the lesions after RFA of hepatic carcinoma.Materials and methods: The data of DW-MRI of 31 patients with hepatic carcinoma before and after RFA and of 20 normal persons were analyzed. The lesions after RFA in the DWI and the change of signal of ROI were analyzed in the DWI and ADC imaging, and ADC values of lesions were measured before RFA and different organizations after RFA. The limiting value of ADC was obtained with pathology or DSA images in control.Results: The sensitivity, specificity, PPV and NPV of CT images in 28 cases and enhanced MRI in 31 cases before RFA were analyed, which showed the highest sensitivity (100%) of contrast-enhanced MRI(CE-MRI)combined with DWI. Results showed that the signal of lesions was more accurate when b value was 600 and 800s/mm~2 in DWI. Thirty one patients with 38 lesions before and after RFA were analyzed in the routine MRI, CE-MRI and DWI, and ADC values of image were measured. ADC values of lesions were acquired by using of overall level measurement and high and low signal area measurement, the differences of ADC values between lesions and normal liver in the ADC imaging with b value 800 s/mm~2 were significant (P< 0.05). Differences of ADC values between lesions and liver tissue around lesions, the lesions and inflammation tissue, the lesions before RFA and after’s, were significant in the ADC imaging with b value 600 and 800 s/mm~2 (P<0.05), where the differences of ADC values were no statistically significant in the ADC imaging with b value 400 s/mm~2 (P>0.05). Differences of ADC values between lesions and coagulation necrotic tissue, lesions and liquefaction necrosis after RFA were significant in the ADC imaging with b value 400, 600 and 800 s/mm~2 (P<0.05).Conclusion: DWI displays a higher sensitivity for tumor detection. And the detection capacity could be even improved by combination of DWI and MRI. ADC value measured is near to the true DC value in the ADC imaging when b value was 800 s/mm~2, if the lesion showed a clear boundary. DWI combined with ADC imaging could show signal differences between tumors and other tissues, such as normal liver parenchyma, inflammatory tissue, and necrotic tissue. A various of pathological types have a relatively specific range of ADC values, which could be as the quantitative evaluation for the RFA efficacy.更多还原