The Value Of DWI In Differenting Primary Hepatocellular Carcinoma And Peripheral Intrahepatic Cholangiocarcinoma

Objective To investigate the value of diffusion-weighted imaging(DWI)in the differential diagnosis of primary hepatocellular carcinoma and peripheral intrahepatic cholangiocarcinoma.Materials and Methods Thirty patients with primary hepatocellular carcinoma(PHCC)and twenty patients with peripheral intrahepatic cholangiocarcinoma(PICC)confirmed by surgery and pathology were collected from the Taihe People's Hospital during the period of October 2012 to June 2015.Thirty cases with PHCC consisted of twenty-six males and four females,the age range was 31-76 years,with the average age of 57.7 years.In thirty patients with PHCC had upper abdominal pain,anorexia,fatigue,accompanied with abdominal mass in four cases.Thirty cases of patients with chronic hepatitis B,liver cirrhosis of the foundation,most of them with liver palm,spider moles and other clinical manifestations.In biochemical examination,there were twenty-nine cases with elevation of aminotransferase,one cases showed no significant abnormal liver function.Tumor marker: In thirty patients with PHCC,twenty-four cases had significant increase in AFP(> 400.00ng/ml)and six cases had no significant increase.In CA-199?CA-125 and CEA,all patients had no significant increase.Twenty cases with PICC consisted of fifteen males and five females,the age range was 46-86 years,with the average age of61.8 years.Nineteen patients with PICC had upper abdominal pain,distention and anorexia,among which eleven cases with jaundice.one patient was found in the physical examination.In twenty patients with PICC,three cases with chronic hepatitis B,cirrhosis history basis,including one patients with splenomegaly,portal hypertension and arteriovenous fistula.In laboratory examination,eleven cases of patients had elevated serum bilirubin,three cases had elevated aminotransferase,and the rest of them showed no significant abnormal changes.Tumor marker: Nine cases had significant increase in CA-199(> 700.00U/ml)and eleven cases had no significant increase.Four cases had significant increase in AFP(> 400.00ng/ml)and sixteen cases had no significant increase.In CA-125 and CEA,all patients had no significant increase.All patients underwent conventional MR imaging and diffusion weighted imaging under 1.5T Avanto Siemens magnetic resonance imaging system.the imaging features of the lesions in the conventional sequences and diffusion-weighted imaging were recorded.The SIEMENS workstation processing software had been used to generate ADC maps from the original diffusion-weighted images when the b value was 800s/mm2.Region of interest(ROI)was drown at the largest plane of the tumor based on the conventional axial T2 weighted images and diffusion-weighted images under the condition of no background of tumor qroup and then the apparent diffusion coefficient(ADC)was measured.Each mass was measured three times and then took the mean value of them.For multiple lesions,the largest one was measured.When measuring the area of interest to choose as much as possible to avoid the tumor cystic degeneration,necrosis,hemorrhage and bile duct,blood vessels,and to avoid the interference of edge artifacts.Besides,the ADC value of the adjacent hepatic parenchyma around the tumor was measured in the same level.The region of interest of the adjacent hepatic parenchyma was drawn as much as possible to avoid the intrahepatic bile duct and the blood vessels.The ADC value of the adjacent hepatic was aslo measured from three different areas and then took the average.Finally,the ADC ratio of tumor to adjacent liver tissue wascalculated.Statistical analysis was performed with SPSS 17.0 statistical software to determine statistical differences.The ADC values of measured were recorded as ‘mean±standard deviation'.The ADC values and the ADC ratio of tumor to adjacent liver tissue in the groups of PHCC and PICC were compared using independent sample T test,respectively.In addition,ROC curve was used to identify the cutoff to differentiate the PHCC and PICC and to determine the sensitivity and specificity.Results Thirty-four lesions of PHCC were detected in thirty cases,among which twenty-six lesions located in the right lobe of the liver,and eight lesions located in the left lobe of the liver.All lesions showed slightly heterogeneous low signal on T1-weighted imaging,lightly higher signal on T2-weighted imaging and high signal on diffusion weighted imaging.Eight lesions had false capsule which showed ring low signal.In thirty patients with primary hepatocellular carcinoma,seven cases underwent dynamic contrast-enhanced MRI.Five cases showed obvious enhancement in arterial phase,and had typical wash in and wash out features.Two cases showed obvious enhancement in arterial phase,but had delay enhancement.Twenty lesions of PICC were detected in twenty cases,among which five lesions located in the right lobe of the liver,and fifteen lesions located in the left lobe of the liver.All lesions showed slightly low signal on T1-weighted imaging,slightly higher signal on T2-weighted imaging and high signal on diffusion weighted imaging.Thirty cases were found dilation of the intrahepatic bile duct around the mass,five cases were found dilated bile ducts in the tumor.Fifteen cases aslo accompanied with local hepatic atrophy.When b=800s/mm2,the mean ADC values in group of PHCC and PICC were(0.89±0.15)×10-3mm2/s and(1.05±0.14)×10-3mm2/s,respectively.There is significant difference between the two groups(t=3.685,P < 0.01).The mean ADC values of the tumor in two groups were lower than those of the adjacent liver parenchyma.The ADCratio of tumor to normal liver tissue of PHCC and PICC were(0.78±0.13)and(0.87±0.09),respectively.There was significant difference between the two groups(t=2.760,P < 0.01).The areas under the ROC curve of the ADC values and the ADC ratio of tumor to normal liver tissue were 0.783(95% CI:0.650~0.916)and 0.732(95% CI:0.590~0.873),respectively.When ADC threshold value was 0.94×10-3mm2/s,the diagnostic sensitivity and specificity were 85% and 70%,respectively.When ADC ratio of tumor to adjacent liver tissue threshold value was 0.83,the diagnostic sensitivity and specificity were 85% and 60%,respectively,which achieved preferable diagnostic efficacy.Conclusion: The ADC value and the ADC ratio of tumor to adjacent liver tissue of the PHCC were lower than PICC,the difference was statistically significant(P < 0.01).Diffusion weighted imaging is valuable to help differentiate PHCC from PICC.