| Objective To analyze the multimode MRI sign and biological characteristics of hepatocellular carcinoma(HCC)with negative alpha-fetoprotein(AFP)for improvinge the radiological diagnosis of HCC.Methods A total of 96 cases of hepatocellular carcinoma confirmed by histopathology were recruited at**hospital and**hospital between June 2016 and December 2017The exclusive criteria were MR contraindications and other interference factors including germinoma,acute severe hepatitis,gastrointestinal,pancreas and biliary tumors,and pregnancy,etc.The interval time between serum AFP test and multimode MRI scan were half month before treatment.According to the normal reference value of concentration of AFP(<20ug/L),the selected samples were divided into negative AFP group(research group)and positive AFP group(control group).Two groups of patients were given multimode MRI,including regular MRI for morphology performances,three-phase dynamic enhanced CT scanning for enhanced characteristics,inspection on differences of the enhanced MRI signals,multi-b diffused weighted imaging(DWI)and quantitative analysis on the corresponding ADC values.Imaging and biological features were compared with between the two groups.Results Among 96 HCC patients,AFP was negative in 38 cases and positive in 58 cases.Among 32 cases of massive type(33.3%)HCC,AFP was negative in 6 cases(15.8%)and positive in the others(26/32,44.8%).In 26 cases of nodular type(27.1%)HCC,negative AFP were 12 cases(31.6%)while positive in 14 cases(24.1%).There were 1 case of negative AFP(2.6%)and 9 cases of positive AFP(15.5%)in total 10 cases of diffused type(10.4%)HCC.Among 28 cases of small hepatic carcinoma(60.4%),AFP was negative in 19 cases(50*0%)and positive in 9 cases(15.5%).There were statistically significant differences between the two groups in differentiations of massive type,diffused type and small hepatic carcinoma(all P<0.05).In the negative AFP group,10 cases(26.3%)were combined with HBV infection,2 cases(5.2%)were combined with HCV infection and 27 cases(71.1%)were combined with liver cirrhosis.On the other hand,45 cases(77.6%)were combined with HBV infection,9 cases(15.5%)were combined with HCV infection,and 41 cases(70.7%)were combined with liver cirrhosis in the positive AFP group.In the comparison analysis on combination condition with HBV between the two groups,there was significant differences(P<0.05).However,No significant differences were existed in the proportion of HCV and liver cirrhosis(P>0.05).The proportions of the negative to positive group in the imaging characteristics of conventional MRI performances were:31 cases(81.6%)vs 34 cases(58.6%)for single lesion,15 cases(39.5%)vs 46 cases(79.3%)for irregular morphology,12 cases(31.6%)vs 36 cases(62.1%)for necrosis,3 cases(7.9%)vs 15 cases(25.9%)for hemorrhage,10 cases(26.3%)vs 33 cases(56.9%)for metastasis,and 4 cases(10.5%)vs:21 cases(36.2%)for vascular invasion,respectively.Comparative analysis suggested statistically significant differences(P<0.05).Three-stage enhanced MRI scanning suggested that 44 cases(75.9%)of the positive AFP group were characterized by high reinforcement at the arterial phase and relative low reinforcement at the venous phase and delayed phase,namely the typical reinforcement characteristics of "wash out";while 22 cases of the negative group(57.9%)were characterized by obvious enhancement at the arterial phase,continuous enhancement at the venous phase,and relatively low enhancement.at the delayed phase,namely the reinforcement mode of "slow out".There were statistically significant differences between the two groups.In the comparison analysis on the differences of the signal values of each two of the groups before and after enhancement,the average differences of the signal values of the negative and positive groups were 657.8 and 590.7,458.9 and 624.6,and 488.35 and 368.3 respectively.The differences of signal value at the portal venous phase maintained higher in the negative group,while obviously lower in the positive group.Comparison analysis suggested statistically significant differences between the two groups in the enhanced signal value at the portal venous phase and the delay phase(P<0.05).Multi-b value DWI imaging was carried out on the two groups to quantitatively analyze the average S(b)/S(0)and changes of ADC value under multi-b values.The study found that the diffused condition in the lesions of the negative group was decreased with the increase of b value.But the decline of the average S(b)/S(0)was more obvious in the negative AFP group than in the positive group with the increase of b value from the site of 200mm2/s.When b value was 50/100/200mm2/s,ADC value in lesions was slightly higher between two groups.Though there was a decline trend,the differences were not large,and there were no significantly statistical differences between two groups(P>0.05).When b value was raised to 400/600/800mm2/s,ADC value of the negative group and the positive group were 2.681± 0.51:1.42±0.17,2.5010.54:1.25±0.20,and 2.20±0.29:1.02±0.17.The decreased amplitude of ADC value in the positive group was obviously larger than that of the negative group,with significant differences(P<0.01).Comparative analysis on histopathological differentiation between the two groups revealed that there were 18 highly-differentiated cases(47.4%),13 moderately-differentiated cases(34.2%)and 7 lowly-differentiated cases(18.4%)in the negative AFP group while 10 highly-differentiated cases(17.2%),22 moderately-differentiated cases(37.9%)and 26 lowly-differentiated cases(44.8%)in the positive AFP group,with statistically significant differences(P<0.05).Conclusion The features of multimode MR imaging for negative-AFP HCC are as follow:the nodular type and small HCC lesions are more often small and regular;single lesion is more frequent;there are less necrosis and hemorrhage within the tumor;and it is not easy to form portal vein tumor thrombus;there are abundant arterial and venous blood supply in the tumor;and the dynamic enhanced MRI scanning is characterized by "slow out,".Restricted diffusion is characterized on DWI.With the gradual increase of b value,the signal intensity decreases relatively quickly,and the corresponding ADC value decreases slowly.The majorities of negative AFP HCC are high or moderate differentiation in histopathology. |
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