| Part IHepatocelluar Carinoma with Nonalcoholic Fatty Liver Background:Quantitative Evaluation of MR Double-echo Chemical Shift T1 Weighted Images and Compared with CT ImagesPurpose:CT and MR scan were performed in patients with hepatocellular carcinoma, the fatty liver background and HCCs were quantitatively evaluated by chemical shift double-echo T1 weighted imaging,and compared with CT scan.Materials and Methods:Between June 2008 and February 2009,the suspected and risk patients with HCC were performed multiple-detector CT and 3-T MR scan.The patients with liver background abnormal were ruled out except for nonalcoholic fatty liver.A total 46 HCC patients were fit into our study(male 39,female 7,ranged 35-76 years old,mean age 50.53 years).The HCC cases were divided into two groups,the fatty liver(11 cases) and normal background of liver(35 cases).The images and clinical data were available in all patients.The ROC curve was used to compared the ability of quantitative evaluation for fat content in the liver at CT and dual-echo T1WI images.The different HCCs features of contrast noise rate(CNR) in fatty liver were also compared at MR images.Result:1.To evaluate the fat content in the liver,the signal intensity(SI) index of dual-echo T1WI showed a linear negative correlation with liver-to-spleen CT value ratio,the correlation was significant(r=-0.487,P=0.007).A significant linear negative correlation (r=-0.474,P=0.007) was also found between the SI index of dual-echo T1WI and liver-to-spleen CT value difference.2.For the evaluation of fatty liver,the area under ROC(area index Az) value of dual-echo T1WI was 0.950±0.031,the Az value of liver-to-spleen CT ratio was 0.938± 0.056,the Az value of liver-to spleen CT value difference was 0.940±0.053.Compared between any two means,the differences were not significant(the P values were 0.85, 0.87,0.44,respectively).3.Compared with the fatty liver group,the CNR of HCCs in control group was higher(-47±8 VS -48±14.1) at the in-phase MR images,but the difference was not significant(P=0.946).At the opposed images,the CNR values of HCCs were -28.12±7.04 and -9.67±11.41,respectively,the difference was not significant(P=0.175) too.4.At the dual-echo T1WI,the mean CNR variation of HCCs in control group and study group was -18.22±3.98 and -38.40±8.86,respectively.The difference was significant(P=0.023).Conclusion:The quantitative evaluation of fat content in the liver for the patients with HCC,the dual-echo T1WI appeared a consistent with CT.The intensity of HCCs at dual-echo T1WI appeared a significant change in the fatty liver background. Purpose:Triple-phase enhancement CT and multiple-phase dynamic-enhancement MR scan were performed in patients with hepatocellular carcinoma(HCC).The diagnostic ability of the two methods was compared.The detectability of dual-arterial phase of MRI and single-artery phase of CT scan for HCCs was evaluated.Materials and methods:Between June 2008 and February 2009,a total of 60 patients suspected or risk of HCC were performed CT and MR scan.59 HCCs were confirmed in 39 patients(male 35,female 4,ranged 35-74 years old,mean aged 56.1 years).CT was performed with routine CT scan and a triple-phase enhancement scan. MR imaging was performed with LAVA technique,the images included mask images, dual-artery phases,dual-portal phases,dual-venous phases and 2-3 minute delayed phase. Three observers evaluated the CT and MR imaging separately,and the results were compared with alternative-free-response ROC(AFROC) curve,the area under ROC(Az) was calculated to compare the diagnostic ability.In addition,the detectability of dual-artery phase of MR images was compared with the single-artery phase of CT images.Result:1.The Az value of CT for the diagnosis of HCC was 0.812±0.0118,the Az value of MR was 0.909±0.0072,the difference was not significant(P value of three observers was 0.15,0.14,0.09,respectively).In the group of less than 1cm in the diameter of HCCs,the sensitivity of CT and MR was 63.9%and 80.5%,the difference was not significant (P=0.013).In the groups of 1-3cm and larger than 3cm of HCCs,the sensitivity of CT and MR appeared no significant difference(P＞0.05).Of all HCCs,the sensitivity of CT was lower than MR(83.6%VS 88.7%),but the difference was not significant(P＞0.05). The positive predict value(PPV) of CT was also lower than MR(93.1 VS 96.3%),but the difference was not significant too(P＞0.05).2.The mid-artery phase had the same sensitivity and PPV with dual-artery phase of MR of 84.6%and 87.95,respectively.The early-artery phase of MR appeared a significantly lower sensitivity of 67.8%(P=0.034),PPV of early-artery phase imaging was 93.6%.The artery phase of CT scan had a sensitivity and PPV of 76.6%and 92.9%, respectively.The sensitivity was lower than double-artery phase of MR imaging,and the PPV was higher,but the difference was not significant(p=0.58).3.In the group of less than 1cm in diameter of HCCs,the sensitivity of CT single-artery phase images and MR dual-artery phase images was 55.5%and 75%, respectively,the later showed a higher sensitivity(P=0.036).In the groups of 1-3cm and＞3cm,the sensitivity of the two technique compared no significant difference(71.2% VS 82.7%,P=0.24.And 95%VS 96.7%,P=0.21).Conclusion:The diagnostic ability of triple-phase enhancement CT and multiple-phase dynamic-enhancement MR scan for HCCs was similar.For the lesions less than 1cm in diameter,the dynamic-enhancement MR was superior to that of contrast-enhancement CT scan.While for the larger ones,the difference was not significant.For the detection of HCCs,the early-artery phase MR images did not provide additional benefit for dual-artery phase enhanced MRI detectability. Purpose:To compare the detectability of MR Dynamic enhancement with that of Contrast-enhanced CT for the detection of local hepatocellular carcinoma(HCC) recurrence post-transcatheter arterial chemoembolization(TACE).Materials and methods:Eighteen patients with 38 HCCs underwent MR and spiral CT scan with a mean interval of 9 days(range,1-21days) after 45 days to 11 months of TACE.The enhanced MRI examination was performed with a LAVA technology on a 3-T unit.Both MRI and CT scan included multiphase imaging.Two observers independently interpreted the CT and MR images blindly.The diagnostic ability of the two techniques was evaluated by comparing the area under the ROC curve(Az value).The sensitivity was also evaluated.Results:Of all 38 HCCs,24(63.2%) lesions were confirmed local recurrence after TACE.The observers appeared a high consistent with the diagnosis(a kappa value of 0.732,P＜0.05).The Az value of contrast-enhancement MRI was higher than that of dynamic enhanced CT scan(0.949 VS 0.751,a P value was 0.037 and 0.050,respectively. The diagnostic ability of MR LAVA was higher than that of dynamic CT scan for the local HCCs recurrence.The sensitivity of contrast-enhancement MRI for the detection of recurrence was higher than CT scan(84.5%vs 43.8%,P＜0.05).Conclusion:Contrast-enhancement MRI has a high diagnostic ability of detecting local recurrence of HCC post transcatheter arterial chemoenbolization comparing contrast-enhanced CT scan.
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