MR T_1WI梯度回波同、反相位序列肝癌信号强度变化规律的研究

Analyzing the MR signal intensity variation of hepatocellular carcinoma on in/opposed phase gradient echo T_1-weighted imaging

目的:分析肝细胞肝癌(HCC)与正常肝组织在同、反相位序列上信号强度相对变化的规律,以及肝癌信号变化与肿瘤大小的相关性。方法:收集病理证实、未经治疗的HCC共113例(女15例,男98例,年龄34～85岁,平均57.55岁)。在MRI同、反相位图像上分别测量正常肝组织和HCC的信号强度。统计分析①计算正常肝组织、HCC在同、反相位上的信号强度,及信号变化指数(SI);②比较正常肝组织、HCC在同、反相位上的信号强度绝对值变化的差异;③分析正常肝组织、HCC在同、反相位上的信号强度正向和负向变化病例数的差异;④计算经肝组织校正后HCC的SI(SI校正),分析SI校正与肿瘤体积的相关性。结果:①113例HCC同相位平均信号强度为739.54±187.95,反相位平均信号强度为724.19±194.58,同、反相位平均信号强度减低15.35±92.66,SIHCC为2.0%。113例正常肝组织同相位平均信号强度为840.58±184.98,反相位平均信号强度为854.63±204.65,同、反相位平均信号强度升高14.05±85.36,SI为-1.7%。两者信号强度变化具有统计学的差异(P=0.002);②HCC同、反相位信号升高(正向)53例、降低(负向)59例;正常肝组织信号升高66例、信号降低47例,差异没有显著性(P=0.425);③SI校正为0.2%～31.6%,平均3.41%。SI校正与肿瘤大小之间没有显著相关性(P=0.997)。结论:正常肝脏组织和HCC在同、反相位信号强度存在正向、负向的变化和程度上的差异;在反相位图像上,HCC和肝组织的对比度要好于同相位图像。HCC的信号变化与肿瘤大小没有相关性。

Objective：To analyze the variation of MR signal intensity from hepatocellular carcinoma（HCC） and normal liver tissue on the in and opposed phase gradient echo T1WI imaging.The relationship between signal intensity variation and tumor size was discussed.Methods：Totally 113 pathologically proved and untreated patients were included in this study（female 15,male 98,age 34～85 years,mean 57.55 years）.MR signal intensity was measured on the corresponding slice and location of both in and opposed phase image.Then,① Signal variation index（SI） of HCC and live tissue between in/opposed phase images were calculated;② Changed signal values between HCC and liver tissue were compared;③ Cases with positive and negative signal intensity alteration between in/opposed phase images were calculates and compared between HCC and liver tissue;④ SI of the HCC was corrected by liver tissue.Then,we analyzed the correlation between corrected HCC SI and tumor size.Results：Of the 113 patients,average signal intensity of HCC on in/opposed phase images was 739.54±187.95 and 724.19±194.58,respectively.The changed value was 15.35±92.66 and SIHCC was 2.0%.Average signal intensity of liver tissue on in/opposed phase images was 840.58±184.98 and 854.63±204.65,respectively.The changed value was-14.05±85.36 and SI liver was-1.7%.Changed signal values between HCC and liver tissue were significant different（P=0.002）.Positive signal intensity alteration was seen in 53 and 66 cases,negative was seen in 59 and 47 cases of the HCC and liver tissue.No significant difference was found between the HCC and liver tissue.The corrected SIHCC was 0.2%～31.6%（mean 3.41%）,no correlation was found between corrected SI HCC and tumor size（P=0.997）.Conclusion：HCC and normal liver tissue could be shown as positive or negative,and various signal intensity alteration on in/opposed phase images.A better HCC/liver contrast was displayed in op-posed phase image comparing to the in phase image.HCC signal variation between in/opposed phase image did not correlate with tumor size.