Expression of OATP1B3 determines uptake of Gd-EOB-DTPA in hepatocellular carcinoma

Liver-specific contrast agents

In the patient with cancer, magnetic resonance imaging is increasingly used as a diagnostic tool for disease detection, lesion characterization, as well as the assessment of treatment response. Although non-contrast T1-weighted and T2-weighted imaging, together with low molecular weight extracellular gadolinium contrast-enhanced T1-weighted magnetic resonance imaging remain the cornerstone for liver assessment, there is increasing recognition of the benefits of liver-specific contrast agents for disease evaluation.

Risk of hypervascularization in small hypovascular hepatic nodules showing hypointense in the hepatobiliary phase of gadoxetic acid-enhanced MRI in patients with chronic liver disease

PURPOSE

The purpose of this study was to elucidate the incidence and risk factors for the progression of hypointense nodules observed in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) of hypervascular hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Hypovascular nodules (112) showing hypointensity in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were examined in 54 patients. All patients underwent computed tomography during hepatic arteriography and computed tomography during arterial portography (CTAP) within a month after Gd-EOB-DTPA-enhanced MRI. According to the tumor size, 112 nodules were divided into two groups: those >10 mm in diameter (group A, n = 39) and those ≤10 mm in diameter (group B, n = 73). The incidence of progression to hypervascular HCC was calculated using the Kaplan-Meier method.

RESULTS

The incidence of hypervascularization was significantly higher in group A nodules than in group B nodules (p < 0.0001). Tumor size (p < 0.0001) and hypoattenuation in CTAP (p = 0.0004) showed significant correlation with hypervascularization.

CONCLUSION

Hypointense nodules observed in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI with diameters of >10 mm had a high probability of hypervascularization.

Hyperintense HCC on hepatobiliary phase images of gadoxetic acid-enhanced MRI: correlation with clinical and pathological features

PURPOSE

To retrospectively determine whether the hyperintense hepatocellular carcinomas (HCCs) seen on the hepatobiliary phase of gadoxetic acid-enhanced MR imaging (EOB-MRI) might have different histologic characteristics from usual hypointense HCCs.

MATERIALS AND METHODS

Two hundred three surgically proven HCCs from 192 patients who underwent preoperative EOB-MRI were analyzed. The demographic and histologic characteristics of hyperintense HCCs were compared with usual hypointense HCCs by using the t-test or Fisher's exact test.

RESULTS

By visual assessment, 18 (8.8%) tumors were classified as hyperintense HCCs. Patients with hyperintense HCC were significantly (p<0.05) older (60.1 vs. 55.2 years) than those with hypointense HCCs. Hyperintense HCCs showed significantly lower rate of microvascular invasion (27.8% vs. 53.5%) and significantly higher rate of peliosis (61.1% vs. 30.8%). Hyperintense HCCs were more frequently expanding type, and none showed infiltrative type or scirrhous histologic pattern.

CONCLUSIONS

Hyperintense HCCs seem to have clinical and histologic features that might be related with more favorable outcomes.

New paradigm for management of hepatocellular carcinoma by imaging

Based on recent clinical practice guidelines, imaging is largely replacing pathology as the preferred diagnostic method for determination of hepatocellular carcinoma (HCC). A variety of imaging modalities, including ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and angiography, are currently used to examine patients with chronic liver disease and suspected HCC. Advancements in imaging techniques such as perfusion imaging, diffusion imaging, and elastography along with the development of new contrast media will further improve the ability to detect and characterize HCC. Early diagnosis of HCC is essential for prompt treatment, which may in turn improve prognosis. Considering the process of hepatocarcinogenesis, it is important to evaluate sequential changes via imaging which would help to differentiate HCC from premalignant or benign lesions. Recent innovations including multiphasic examinations, high-resolution imaging, and the increased functional capabilities available with contrast-enhanced US, multidetector row CT, and MRI have raised the standards for HCC diagnosis. Although hemodynamic features of nodules in the cirrhotic liver remain the main diagnostic criterion, newly developed cellspecific contrast agents have shown great possibilities for improved HCC diagnosis and may overcome the diagnostic dilemma associated with small or borderline hepatocellular lesions. In the 20th century paradigm of medical imaging, radiological diagnosis was based on morphological characteristics, but in the 21st century, a paradigm shift to include biomedical, physiological, functional, and genetic imaging is needed. A multidisciplinary team approach is necessary to foster an integrated approach to HCC imaging. By developing and combining new imaging modalities, all phases of HCC patient care, including screening, diagnosis, treatment, and therapy, can be dramatically improved.

Multiple hepatocellular adenomas in a patient with glycogen storage disease type I: various enhancement patterns in MRI with Gd-EOB-DTPA

The patient is a 20-year-old man with glycogen storage disease type I (GSD-type I). In his teens, multiple focal hepatic masses were detected on abdominal ultrasonography (US), which were diagnosed as multiple hepatocellular adenomas from the imaging. During follow-up, these masses had shown intermittent growth in size. In the evaluation of Gd-EOB-DTPA (gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid) MR imaging, these masses showed various signal intensities from hypo- to hyperintense during the hepatocyte-specific phase. Intermittent growth and elevation of serum PIVKA-II levels indicate the potential for malignant transformation, so the patient underwent partial hepatectomy. The resected masses were all consistent with benign hepatocellular adenomas histopathologically.

Intranodular signal intensity analysis of hypovascular high-risk borderline lesions of HCC that illustrate multi-step hepatocarcinogenesis within the nodule on Gd-EOB-DTPA-enhanced MRI

OBJECTIVES

To analyze intranodular signal intensity pattern of hypovascular high-risk borderline lesions of HCC that illustrate multi-step hepatocarcinogenesis within the nodule on Gd-EOB-DTPA-enhanced MRI.

METHODS

A total of 73 nodules showing hypervascular foci in hypovascular high-risk borderline lesions identified by angiography-assisted CT were included in this study. The intranodular signal intensities of both the hypervascular foci and the hypovascular high-risk borderline lesions were evaluated on hepatobiliary-phase EOB-enhanced MRI obtained 20 min after intravenous injection of contrast media.

RESULTS

Among 59 hypervascular foci within hypointense hypovascular high-risk borderline lesions, 6 showed more hypointensity, 32 isointensity, and 21 hyperintensity compared to the surrounding hypointense, hypovascular portion of the nodules. Among 14 hypervascular foci within isointense hypovascular high-risk borderline lesions, 5 showed isointensity, and 9 hypointensity compared to the surrounding isointense hypovascular high-risk borderline lesions. No hypervascular foci showed hyperintensity compared to the surrounding isointense hypovascular high-risk borderline lesions.

CONCLUSIONS

In most of the hypovascular high-risk borderline lesions containing hypervascular foci within the nodule, the signal intensity was decreased in hypervascular foci as compared with hypovascular high-risk borderline lesions and the surrounding background liver parenchyma. This supports the concept of signal intensity decrease during the dedifferentiation process in multistep hepatocarcinogenesis. However, around 30% of the nodules did not follow this rule, and hypervascular foci showed hyperintensity relative to the hypovascular high-risk borderline lesions.

Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA

OBJECTIVES

To apply dynamic contrast-enhanced (DCE) MRI on patients presenting with elevated liver enzymes without clinical signs of hepatic decompensation in order to quantitatively compare the hepatocyte-specific uptake of Gd-EOB-DTPA with histopathological fibrosis stage.

METHODS

A total of 38 patients were prospectively examined using 1.5-T MRI. Data were acquired from regions of interest in the liver and spleen by using time series of single-breath-hold symmetrically sampled two-point Dixon 3D images (non-enhanced, arterial and venous portal phase; 3, 10, 20 and 30 min) following a bolus injection of Gd-EOB-DTPA (0.025 mmol/kg). The signal intensity (SI) values were reconstructed using a phase-sensitive technique and normalised using multiscale adaptive normalising averaging (MANA). Liver-to-spleen contrast ratios (LSC_N) and the contrast uptake rate (K (Hep)) were calculated. Liver biopsy was performed and classified according to the Batts and Ludwig system.

RESULTS

Area under the receiver-operating characteristic curve (AUROC) values of 0.71, 0.80 and 0.78, respectively, were found for K (Hep), LSC_N10 and LSC_N20 with regard to severe versus mild fibrosis. Significant group differences were found for K (Hep) (borderline), LSC_N10 and LSC_N20.

CONCLUSIONS

Liver fibrosis stage strongly influences the hepatocyte-specific uptake of Gd-EOB-DTPA. Potentially the normalisation technique and K (Hep) will reduce patient and system bias, yielding a robust approach to non-invasive liver function determination.

Visualization of hepatic uptake transporter function in healthy subjects by using gadoxetic acid-enhanced MR imaging

PURPOSE

To determine if genetic polymorphisms of liver-specific human organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 influence cellular uptake of gadoxetic acid in vitro and if functionally relevant polymorphisms are confounders for liver enhancement by gadoxetic acid in healthy subjects.

MATERIALS AND METHODS

This study received ethics approval, and all subjects provided written informed consent. Cellular uptake of gadoxetic acid by OATP1B1 and OATP1B3 and their frequent genetic variants was measured by using stable transfected embryonic kidney HEK293 cells. Liver signal intensity at gadoxetic acid-enhanced MR imaging and pharmacokinetics of gadoxetic acid were evaluated in 36 healthy carriers of SLCO1B1/1B3 wild-type alleles (n = 10), SLCO1B1*1b/*1b (n = 8), SLCO1B1*15/*15 (n = 7), SLCO1B1*5/*15 (n = 1), SLCO1B1*1a/*5 (n = 6), and SLCO1B3*4/*4 (n = 4) by using T1-weighted MR imaging and liquid chromatography tandem mass spectrometry.

RESULTS

Transport activity for gadoxetic acid was increased in cells transfected with SLCO1B1c.388A>G (12.8 pmol/[mg·min]6 3.53, P = .001) but decreased in cells with SLCO1B1c.388A>G/521T>C (3.11 pmol/[mg·min] ± 0.918, P = .004) compared with cells with nonvariant transporter (6.32 pmol/[mg·min] ± 2.73). Compared with activity of cells transfected with the nonvariant SLCO1B3 (7.43 pmol/[mg·min] ± 2.43), SLCO1B3c.699G>A was a gain-of-function variant (15.1 pmol/[mg·min] ± 5.52, P = .002), whereas SLCO1B3c.334T>G (0.364 pmol/[mg·min] ± 0.125, P = .0001) and SLCO1B3c.1564G>T (0.295 pmol/[mg·min] ± 0.247, P = .0001) were variants with lower function. Liver enhancement with gadoxetic acid was reduced in subjects with OATP1B1*1a/*5 compared with wild-type subjects and those with OATP1B1*1b/*1b (area under enhancement curve, 3-480 minutes in arbitrary units [au]; 20.7 au ± 6.85 vs 36.5 au ± 8.08 [P = .006] vs 34.6 au ± 8.92 [P = .026]). The OATP1B3*4 polymorphism was not of functional relevance. No pharmacokinetic characteristics of gadoxetic acid were influenced by genetic polymorphisms of OATP1B1 and OATP1B3.

CONCLUSION

Liver-specific OATP1B1 and OATP1B3 are uptake carriers for gadoxetic acid in subjects. Genetic polymorphisms of OATP1B1 are signal confounders in gadoxetic acid-enhanced liver MR imaging.

Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging predicts the histological grade of hepatocellular carcinoma only in patients with Child-Pugh class A cirrhosis

The aim of this study was to investigate the role of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) in predicting the histological grade of hepatocellular carcinoma (HCC) according to the hepatic function. Eighty-one consecutive patients with 122 histologically proven HCCs who underwent Gd-EOB-DTPA-enhanced MRI before resection (45 HCCs in 42 patients) or transplantation (77 HCCs in 39 patients) were analyzed retrospectively. We calculated the relative enhancement ratios (RER), which is the ratio of the relative intensity of a tumor versus the surrounding parenchyma on hepatobiliary phase images to the relative intensity on unenhanced MRI scans. We then analyzed the correlation between the RER and the tumor differentiation grade in patients with various degrees of hepatic function. The degree of tumor enhancement, which included the precontrast relative intensity ratio (RIR), the postcontrast RIR, and the RER, for well-differentiated (WD) HCCs was significantly higher than the degree of tumor enhancement for moderately differentiated and poorly differentiated (PD) HCCs (P = 0.001 and P = 0.001, respectively, for precontrast RIRs; P < 0.001 and P < 0.001, respectively, for postcontrast RIRs; and P = 0.01 and P = 0.001, respectively, for RERs). In a subgroup analysis based on liver function, the correlation between the histological grade and the enhancement ratio was demonstrated only in the group of patients with Child-Pugh class A cirrhosis. The accuracy of postcontrast RIRs for predicting WD and PD HCCs was favorable; the areas under the receiver operating characteristic curves were 0.896 [95% confidence interval (CI) = 0.817-0.974] and 0.769 (95% CI = 0.658-0.879), respectively. In conclusion, the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI may help to predict the differentiation of HCCs, especially in HCC patients with Child-Pugh class A cirrhosis before liver transplantation or resection.

Noninvasive diagnosis of hepatocellular carcinoma in cirrhotic liver: current guidelines and future prospects for radiological imaging

Noninvasive imaging has become the standard for hepatocellular carcinoma (HCC) diagnosis in cirrhotic patients. Typical imaging features of HCC such as arterial wash-in and venous wash-out deliver very high specificity and acceptable sensitivity even in nodules from 1 to 2 cm in diameter. However, limitations apply specifically in hypovascular HCC, for which the addition of new techniques such as diffusion-weighted magnetic resonance imaging (DW-MRI) or hepatobiliary MRI is helpful. Whereas DW-MRI adds to both the sensitivity and specificity, hepatobiliary MRI additionally contributes valuable information in cirrhotic patients on the histopathology of small lesions, including early HCC and high-grade dysplastic nodules. Biopsy of small, atypical lesions is associated with a high rate of false-negative findings and should be used only after careful consideration in selected patients. Here, we review the current international guidelines on HCC diagnosis as well as the latest developments in imaging that may contribute to safe detection and accurate characterization of suspicious nodules in patients with liver cirrhosis.

Can the biliary enhancement of Gd-EOB-DTPA predict the degree of liver function?

BACKGROUND

Excretion of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in the bile may be related to liver function, because of elimination from the liver after preferential uptake by hepatocytes. The purpose of this study was to investigate the relation between liver and biliary enhancement in patients with or without liver dysfunction, and to compare the tumor-to-liver contrast in these patients.

METHODS

Forty patients [group 1: normal liver and Child-Pugh class A in 20 patients, group 2: Child-Pugh class B in 18 patients and Child-Pugh C in 2] were evaluated. All patients underwent MR imaging of the liver using a 1.5-Tesla system. T1-weighted 3D images were obtained at 5, 10, 15 and 20 minutes after Gd-EOB-DTPA injection. The relation between group 3 (total bilirubin <1.8 mg/dL) and group 4 (total bilirubin ≥1.8 mg/dL) was investigated at 20 minutes. Liver and biliary signals were measured, and compared between groups 1 and 2 or groups 3 and 4. Tumor-to-liver ratio was also evaluated between groups 1 and 2. Scheffe's post-hoc test after two-way repeated-measures ANOVA and Pearson's correlation test were used for statistical analysis.

RESULTS

Liver enhancement showed significant difference at all time points between groups 1 and 2. Biliary enhancement did not show a significant difference between groups 1 and 2 at 5 minutes, but did at 10, 15 and 20 minutes. At 20 minutes, significant differences between groups 3 and 4 were seen for liver and biliary enhancement. At all time points, liver enhancement correlated with biliary enhancement in both groups. At 5 minutes and 20 minutes, statistical differences between groups 1 and 2 were seen for tumor-to-liver ratio.

CONCLUSIONS

The degree of biliary enhancement has a close correlation to that of liver enhancement. It is especially important that insufficient liver enhancement causes lower tumor-to-liver contrast in the hepatobiliary phase of Gd-EOB-DTPA.

Hepatocyte transporter expression in FNH and FNH-like nodule: correlation with signal intensity on gadoxetic acid enhanced magnetic resonance images

PURPOSE

Our aim was to evaluate the hepatocyte transporters in focal nodular hyperplasia (FNH) and FNH-like lesions and to correlate the grade of its expression with signal intensity on the hepatobiliary phase (HB phase) of gadoxetic-acid-enhanced magnetic resonance imaging (EOB-MRI).

MATERIALS AND METHODS

Thirteen histopathological confirmed cases including eight with EOB-MRI were studied. Immunohistochemical staining for transporter was performed and its grade semiquantitatively analyzed.

RESULTS

Histopathologically, ten cases showed almost equal organic anion transporter polypeptide (OATP) 8 expression relative to the surrounding liver; the remaining three showed stronger OATP8 expression. In eight cases with EOB-MRI, two demonstrated more hyperintensity on the HB phase, and their OATP8 expression was stronger compared with the surrounding liver. The remaining six cases showed isointensity on the HB phase and revealed almost equal OATP8 expression. The expression of export transporter multi-drug-resistant proteins (MRP) 1 and 2 were almost equal relative to the surrounding liver in most cases (11/12, 92 %; 11/12, 92 %, respectively), whereas MRP3 focally overexpressed in 75 % (9/12) of cases.

CONCLUSION

FNH and FNH-like nodules revealed equal or stronger OATP8 expression than background liver. OATP8 expression showed significant correlation with signal intensity on the HB phase.

Which is the best MRI marker of malignancy for atypical cirrhotic nodules: hypointensity in hepatobiliary phase alone or combined with other features? Classification after Gd-EOB-DTPA administration

PURPOSE

To investigate whether the malignancy of atypical nodules in cirrhosis can be identified at gadoxetic-acid-disodium(Gd-EOB-DTPA)-MRI by their hypointensity in the hepatobiliary(HB)-phase alone or combined with any other MR imaging features.

MATERIALS AND METHODS

One hundred eleven atypical nodules detected in 77 consecutive Gd-EOB-DTPA-MRIs were divided, based on arterial-phase behavior, into: Class I, isovascular (n = 82), and Class II, hypervascular without portal/delayed washout (n = 29). The two classes were further grouped based on HB-phase intensity (A/B/C hypo/iso/hyperintensity). Portal/venous/equilibrium-phase behavior and T2w features were also collected. Histology was the gold standard. Per-nodule sensitivity, specificity, negative and positive predictive values (NPV/PPV), and diagnostic accuracy were calculated for HB-phase hypointensity alone, and combined with vascular patterns and T2w hyperintensity.

RESULTS

Histology detected 60 benign and 51 malignant/premalignant nodules [10 overt hepatocellular carcinomas (HCCs) and 41 high-grade dysplastic nodules (HGDN)/early HCC]. Class IA contained 31 (94%) malignancies, IB one (3%), and IC only benign lesions. Class IIA had 100% malignancies, IIB three (37.5%) and IIC only two (28.5%). HB-phase hypointensity alone (Classes I-IIA) had 88% sensitivity, 91% NPV, and 93% diagnostic accuracy, superior (P < 0.05, P < 0.006, and P < 0.05, respectively) to any other MR imaging feature alone or combined.

CONCLUSION

In atypical cirrhotic nodules, HB-phase hypointensity by itself is the strongest marker of malignancy.

Possible utility of MRI using Gd-EOB-DTPA for estimating liver functional reserve

BACKGROUND

Preoperative estimation of the liver functional reserve is important in liver surgery. We evaluated the role of dynamic magnetic resonance (MR) imaging with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), i.e., EOB-MRI, for determining liver functional reserve.

METHODS

Fifty patients who underwent EOB-MRI to examine their liver tumors were included in this study. We first performed a pixel-by-pixel comparison of registered MR images and activity images with Tc-99m galactosyl human serum albumin (GSA) on each slice, and the correlation coefficient was calculated for 8 patients. We also determined the correlation coefficient between the relative signal intensity (SI) values of EOB-MRI and preoperative liver function, such as the GSA, indocyanine green dye retention at 15 min (ICGR15), and prothrombin time.

RESULTS

The mean of the correlation coefficients for 512 × 512 matrices between the EOB-MRI and the GSA was 0.83 ± 0.05 (ranging from 0.73 to 0.87). The correlation coefficient between the relative SI of the EOB-MRI and the receptor index (LHL15) of GSA was 0.56 (P < 0.01). Better correlation coefficients were observed between the relative SI and the liver function test, including ICGR15 (r = -0.67, P < 0.01) and prothrombin time (r = 0.59, P < 0.01). In a patient with hilar cholangiocarcinoma whose right hepatic duct was obstructed, the relative SI in the right lobe (2.4 ± 0.3) was significantly lower than that in the left lobe (3.1 ± 0.1).

CONCLUSION

EOB-MRI represents a practical and reliable imaging technique that may be used to estimate regional liver functional reserve in the clinical setting.

Potential clinical factors affecting hepatobiliary enhancement at Gd-EOB-DTPA-enhanced MR imaging

OBJECTIVE

The objective was to clarify the clinical factors that might affect the degree of hepatic parenchymal enhancement at gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging.

MATERIALS AND METHODS

A total of 84 patients with (n=63) and without chronic liver disease (n=21) underwent Gd-EOB-DTPA-enhanced MR imaging. Contrast-enhanced MR images of hepatobiliary phase (HP) were obtained at 20 min after Gd-EOB-DTPA administration. The relative enhancement (RE) of liver parenchyma at 20 min HP was calculated from region of interest measurements at each patient. Then, these results were correlated with various clinical parameters using Pearson correlation coefficient or Spearman rank correlation coefficient. Furthermore, the predictor of the degree of hepatic parenchymal enhancement was determined using multiple regression analysis.

RESULTS

The presence or absence of chronic liver disease (P=.002), ascites (P=.005) and splenomegaly (P=.027), and the values of prothrombin activity (P=.008), total bilirubin (T-Bil) (P=.001), albumin (P=.001), aspartate aminotransferase (AST) (P=.002) and cholinesterase (P=.007) were significantly correlated with the RE of liver parenchyma at 20 min HP. Among these parameters, increases of T-Bil (P=.011 to .028) and AST (P=.018 to .049) were predictors of decreased hepatic parenchymal enhancement.

CONCLUSIONS

Hepatic parenchymal enhancement of Gd-EOB-DTPA was affected by various clinical parameters. Impaired hepatobiliary enhancement may be predicted by routine biochemical tests, such as T-Bil and AST.

Prediction of the histopathological grade of hepatocellular carcinoma using qualitative diffusion-weighted, dynamic, and hepatobiliary phase MRI

OBJECTIVES

To investigate the effectiveness of qualitative diffusion-weighted imaging (DWI), subtraction of unenhanced from arterial phase images, and hepatobiliary phase (HBP) images in estimating the histopathological grade of hepatocellular carcinoma (HCC).

METHODS

We retrospectively reviewed gadoxetic acid-enhanced magnetic resonance images of 175 patients with 201 surgically resected HCCs. The signal intensity and its relationship with histopathological grade were assessed for each sequence and a combination of sequences.

RESULTS

There was a tendency towards higher grades in tumours showing restricted diffusion on DWI (P < 0.001) or arterial enhancement on subtraction imaging (P < 0.001), but not hepatocyte-defect on HBP images (P = 0.33). When lesions were divided into three groups based on combined findings on DWI and subtraction imaging, a linear trend was observed between group and grade (P < 0.001). The positive predictive value (PPV) of the combination of no restricted diffusion and no arterial enhancement in predicting well-differentiated HCC was 100%, higher than the PPV of individual findings on DWI (74%) or subtraction imaging (81%).

CONCLUSIONS

DWI and subtraction imaging are helpful for predicting the histopathological grade of HCC, especially when the two sequences are considered together.

KEY POINTS

• Predicting the histopathological grade of hepatocellular carcinoma (HCC) preoperatively is important. • Diffusion-weighted imaging (DWI) and subtraction imaging are recently developed MR techniques. • Retrospective study showed DWI and subtraction imaging helps predict HCC grades. • Management of patients with HCC becomes more appropriate.

Appearance of hepatocellular adenomas on gadoxetic acid-enhanced MRI

OBJECTIVE

The purpose of this study was to evaluate enhancement characteristics of hepatocellular adenomas (HCAs) using gadoxetic acid as a hepatocyte-specific MR contrast agent.

METHODS

Twenty-four patients with histopathologically proven HCAs were retrospectively identified. MRI consisted of T1- and T2-weighted (w) sequences with and without fat saturation (fs), multiphase dynamic T1-w images, and fs T1-w images during the hepatobiliary phase. Standard of reference was surgical resection (n = 19) or biopsy (n = 5). Images were analysed for morphology and contrast behaviour including signal intensity (SI) measurement on T1-w images normalised to the pre-contrast base line.

RESULTS

In total 34 HCAs were evaluated. All HCAs showed enhancement in the arterial phase; 38 % of HCAs showed reduced contrast enhancement ("wash-out") in the venous phase. All HCAs showed enhancement (SI increase, 56 ± 53 %; P <0.001) in the hepatobiliary phase, although liver uptake was stronger (96 ± 58 %). Thus, 31 of all HCAs (91 %) appeared hypointense to the surrounding liver in the hepatobiliary phase, while 3 out of 34 lesions were iso-/hyperintense.

CONCLUSIONS

Gadoxetic acid accumulates in HCAs in the hepatobiliary phase, although significantly less than in surrounding liver. Thus, HCA appears in the vast majority of cases as a hypointense lesion on hepatobiliary phase images.

KEY POINTS

• Magnetic resonance-specific contrast agents are now available for hepatic imaging. • Hepatocellular adenomas enhance with gadoxetic acid as in previous CT/MRI experience. • Enhancement during the hepatobiliary phase is less in HCAs than in liver. • Typical HCAs appear as hypointense lesions on T1-w hepatobiliary phase images. • True hyperintense HCA enhancement can occasionally occur during the hepatobiliary phase.

Gadoxetate acid-enhanced MRI of hepatocellular carcinoma in a c-myc/TGFα transgenic mouse model including signal intensity and fat content: initial experience

Genetically engineered mouse models, such as double transgenic c-myc/TGFα mice, with specific pathway abnormalities might be more successful at predicting the clinical response of hepatocellular carcinoma (HCC) treatment. But a major drawback of the tumour models is the difficulty of visualizing endogenously formed tumours. The optimal imaging procedure should be brief and minimally invasive. Magnetic resonance imaging (MRI) satisfies these criteria and gadoxetate acid-enhanced MRI improves the detection of HCC. Fat content is stated to be an additional tool to help assess tumour responses, for example, in cases of radiofrequency ablation. Therefore the aim of this study was to investigate if gadoxetate acid-enhanced MRI could be used to detect HCC in c-myc/TGFα transgenic mice by determining the relation between the signal intensity of HCC and normal liver parenchyma and the corresponding fat content as a diagnostic marker of HCC. In our study, 20 HCC in c-myc/TGFα transgenic male mice aged 20–34 weeks were analyzed. On gadoxetate acid-enhanced MRI, the signal intensity was 752.4 for liver parenchyma and 924.5 for HCC. The contrast to noise ratio was 20.4, the percentage enhancement was 267.1% for normal liver parenchyma and 353.9% for HCC. The fat content was 11.2% for liver parenchyma and 16.2% for HCC. There was a correlation between fat content and signal intensity with r = 0.7791. All parameters were statistically significant with P < 0.05. Our data indicate that gadoxetate acid contrast enhancement allows sensitive detection of HCC in c-myc/TGFα transgenic mice and determination of the fat content seems to be an additional useful parameter for HCC.

Clinical significance of the transitional phase at gadoxetate disodium-enhanced hepatic MRI for the diagnosis of hepatocellular carcinoma: preliminary results

OBJECTIVES

To investigate the clinical significance of the "transitional phase" at gadoxetate disodium (Gd-EOB)-enhanced magnetic resonance imaging for diagnosing hepatocellular carcinoma (HCC).

METHODS

We studied 54 patients with 70 histologically diagnosed HCC. Transitional- and hepatobiliary-phase (TP, HBP) images were acquired 3 and 20 minutes after Gd-EOB injection, respectively. Radiologists measured the size of the hepatic tumors on images and surgical specimens and qualitatively evaluated the signal intensity of the hepatic tumors during TP and HBP independently.

RESULTS

In 4 patients with portal tumor embolism who had undergone percutaneous transhepatic portal embolization and who manifested arterioportal (AP) shunts, the low-intensity area was larger during HBP than TP. Of the 70 HCCs, 4 were of high signal intensity during HBP and 2 were of slightly low intensity during TP.

CONCLUSION

Tumor extension seen during TP rather than HBP more accurately reflected histological findings in patients with HCC with portal tumor thrombi, percutaneous transhepatic portal embolization, or AP shunt.

Different signal intensity at Gd-EOB-DTPA compared with Gd-DTPA-enhanced MRI in hepatocellular carcinoma transgenic mouse model in delayed phase hepatobiliary imaging

PURPOSE

To evaluate hyperintense Gd-DTPA- compared with hyper- and hypointense Gd-EOB-DTPA-enhanced magnet resonance imaging (MRI) in c-myc/TGFα transgenic mice for detecting hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Twenty HCC-bearing transgenic mice with overexpression of the protooncogene c-myc and transforming growth factor-alpha (TGF-α) were analyzed. MRI was performed using a 3-T MRI scanner and an MRI coil. The imaging protocol included Gd-DTPA- and Gd-EOB-DTPA-enhanced T1-weighted images. The statistically evaluated parameters are signal intensity (SI), signal intensity ratio (SIR), contrast-to-noise ratio (CNR), percentage enhancement (PE), and signal-to-noise ratio (SNR).

RESULTS

On Gd-DTPA-enhanced MRI compared with Gd-EOB-DTPA-enhanced MRI, the SI of liver was 265.02 to 573.02 and of HCC 350.84 to either hyperintense with 757.1 or hypointense with 372.55 enhancement. Evaluated parameters were SNR of HCC 50.1 to 56.5/111.5 and SNR of liver parenchyma 37.8 to 85.8, SIR 1.32 to 1.31/0.64, CNR 12.2 to 26.1/-30.08 and PE 42.08% to 80.5/-98.2%, (P < 0.05).

CONCLUSION

Gd-EOB-DTPA is superior to Gd-DTPA for detecting HCC in contrast agent-enhanced MRI in the c-myc/TGFα transgenic mouse model and there was no difference between the hyperintense or hypointense appearance of HCC. Either way, HCCs can easily be distinguished from liver parenchyma in mice.

Well-differentiated hepatocellular carcinoma detected as hypovascularity by only CT during hepatic arteriography

We describe a well-differentiated hepatocellular carcinoma (HCC) with alcohol-related liver cirrhosis in a 69-year-old man. Ultrasonography (US) disclosed a 10 mm hypoechoic nodule in segment 4; Sonazoid contrast-enhanced US and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) revealed no defect in either the Kupffer phase or the hepatobiliary phase. Computed tomography during hepatic arteriography (CTHA), however, revealed a hypovascular nodule, but CT during arterial portography showed no perfusion defect. Histological analysis indicated a well-differentiated HCC. Thus, our detection of well-differentiated HCC disclosed by only CTHA attested to the efficiency of this modality, suggesting that it is more sensitive than Gd-EOB-GTPA-enhanced MRI.

Pharmacokinetics and imaging properties of Gd-EOB-DTPA in patients with hepatic and renal impairment

OBJECTIVES

: The purpose of this study was to determine the pharmacokinetics (PKs), imaging properties, and safety of the liver-specific magnetic resonance (MR) imaging contrast agent gadoxetic acid disodium (Gd-EOB-DTPA) in subjects with various levels of hepatic impairment, renal impairment, or coexisting hepatic and renal impairment.

MATERIALS AND METHODS

: In this single-center, open-label, parallel-group study, patients with varying degrees of renal and/or hepatic impairment were compared with healthy subjects matched for age, gender, and weight (control group). All subjects received a single intravenous bolus of Gd-EOB-DTPA (Primovist, Eovist, EOB-Primovist) 25 μmol/kg body weight. Samples of serum, urine, and feces were collected for PK analysis. MR imaging was performed before dosing and at preset times after dose administration to determine enhancement relative to predose signal intensity values. Safety was assessed by monitoring adverse events, laboratory values, vital signs, cardiac rhythm, oxygen saturation, and by physical examination findings.

RESULTS

: Gd-EOB-DTPA was well tolerated by all subjects. Total clearance of Gd-EOB-DTPA did not significantly change in patients with mild and moderate hepatic impairment (Child-Pugh A and B), compared with the control group. Mean urinary excretion was increased and mean fecal excretion was decreased in patients with hepatic impairment. Renal excretion was increased to between 72% and 96% of the dose administered in patients with very high bilirubin levels (>3 mg/dL), compared with 48% in the control group. Total clearance of Gd-EOB-DTPA was significantly reduced to 140 ± 45 mL/min and terminal elimination half-life (t1/2) was slightly, but not significantly, increased to 2.6 ± 0.9 hours in patients with severe hepatic impairment (Child-Pugh C), compared with the control group (209 ± 37 mL/min and 1.8 ± 0.2 hours, respectively). Liver MR signal enhancement (area under the curve of relative enhancement [%] over time) was similar in patients with mild and moderate hepatic impairment and in those in the control group, but was decreased by 38% in patients with severe hepatic impairment, compared with control. Peak liver enhancement, however, was still at a high level (118% ± 57%). PK and imaging parameters were not significantly affected in patients with moderate renal impairment (creatinine clearance, 30-50 mL/min). In patients with end-stage renal failure (ESRF), however, the PK profile of Gd-EOB-DTPA was significantly different, with an increased t1/2 (20.0 ± 7.0 hours vs. 1.8 ± 0.2 hours in the control group). During a 3-hour dialysis session that started 1 hour after administration of the intravenous dose, the serum levels in patients with ESRF declined by between 71% and 88% as a result of elimination by hemodialysis and parallel hepatobiliary excretion. This is comparable with the decline observed in healthy subjects (85%) during the 1- to 4-hour interval after injection.

CONCLUSIONS

: The results of the present study show that in humans with moderate renal impairment and mild-to-moderate hepatic impairment, no relevant changes in PK parameters, such as total clearance and t1/2, develop as a result of increased renal excretion to compensate in the case of hepatic impairment (or increased hepatic elimination in the case of renal impairment). The t1/2 of Gd-EOB-DTPA was markedly altered only in patients with ESRF. The high MR signal enhancement profile, observed even in patients with severe hepatic impairment, indicates that there is no need to adjust the dose of Gd-EOB-DTPA.

Diagnostic imaging of hepatocellular carcinoma: recent progress

The diagnostic imaging of hepatocellular carcinoma (HCC) has recently undergone marked progress. The advent of the ultrasound (US) contrast agent Sonazoid, approved in January 2007, and magnetic resonance imaging (MRI) with the liver-specific MRI contrast agent gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA-MRI), approved in January 2008, are of particular significance. Sonazoid contrast-enhanced US (Sonazoid-CEUS) is useful not only for the diagnosis of HCC, but also for guiding treatment and assessing treatment response. Sonazoid-CEUS has proven to be particularly effective for screening and staging, which used to be considered impossible with CEUS, through the introduction of the newly developed diagnostic technique of defect reperfusion imaging. It is still not possible if other vascular agents such as SonoVue and Definity are used. In particular, Gd-EOB-DTPA-MRI has been suggested to be much more reliable in the differentiation of early HCC from precancerous dysplastic nodules than any other modalities such as multidetector raw computed tomography, dynamic MRI, and superparamagnetic iron oxide-MRI. A decrease in contrast uptake in the hepatocyte phase observed on EOB-MRI is strongly suggestive of cancer, and the absence of early staining in the arterial phase suggests early HCC. The differential diagnostic capacity of Gd-EOB-DTPA-MRI is considered to far exceed that of what were previously the most useful imaging techniques, computed tomography (CT) during hepatic arteriography or CT during arterial portography, and to be comparable to that of the pathological diagnosis by pathologists specialized in liver.

Magnetic resonance imaging of focal liver lesions: approach to imaging diagnosis

This article is a review of magnetic resonance imaging (MRI) of incidental focal liver lesions. This review provides an overview of liver MRI protocol, diffusion-weighted imaging, and contrast agents. Additionally, the most commonly encountered benign and malignant lesions are discussed with emphasis on imaging appearance and the diagnostic performance of MRI based on a review of the literature.

Hepatocellular carcinoma arising from hepatocellular adenoma in a hepatitis B virus-associated cirrhotic liver

Hepatocellular adenoma (HCA) is a rare, benign proliferation of hepatocytes that occurs mostly in a normal liver and in extreme rare cases, occurs in a cirrhotic liver. Hepatocellular carcinomas (HCC) arising within HCA through malignant transformation is rare. The specific incidence and mechanism of malignant transformation has not been established, but the long term use of oral contraceptives is considered a causative agent. We report a case of HCC arising from HCA detected in a hepatitis B-related cirrhotic liver with serial radiologic images.

Contrast-enhanced MR cholangiography (MRCP) with GD-EOB-DTPA in evaluating biliary complications after surgery

PURPOSE

We assessed the usefulness of contrast-enhanced magnetic resonance cholangiography (CE-MRC) with liver-specific contrast agent in evaluating the biliary tree after hepatic surgery.

MATERIALS AND METHODS

A total of 142 patients with suspected biliary complications after liver surgery underwent hepatobiliary MR before and after administration of gadolinium ethoxy benzylic diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). Unenhanced MR cholangiopancreatography (MRCP) and postcontrast MRC were obtained in all patients. Blinded image evaluation and semiquantitative analysis comparing MRCP and CE-MRC were performed by two experienced radiologists.

RESULTS

In all cases, optimal postcontrast visualisation of the biliary tract was obtained. In 22 patients, a postsurgical biliary complication was confirmed. MRCP detected 64% of lesions, but in 36% of cases, an alteration was only suspected but not clearly defined. CE-MRC allowed definite diagnosis in 100% of cases.

CONCLUSIONS

Hepatobiliary-specific contrast agents allow for accurate and extensive study of biliary tract alterations, especially in assessing postsurgical complications.

Gadoxetic acid-enhanced MRI findings of early hepatocellular carcinoma as defined by new histologic criteria

PURPOSE

To describe the imaging features of early hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI (Gd-EOB-MRI) in comparison with multidetector computed tomography (MDCT) examinations.

MATERIALS AND METHODS

We analyzed imaging findings of 19 pathologically proven early HCC lesions in 15 patients who underwent both MDCT and Gd-EOB-MRI at 3.0 Tesla (T) units before surgery. MRI included in-phase and out-of-phase T1-weighted dual-echo gradient-recalled-echo sequences, dynamic T1-weighted images before and after bolus injection of gadoxetic acid disodium, fat-saturated T2-weighted fast spin-echo sequences, and T1-weighted hepatobiliary phase images 20 min after contrast injection. Two radiologists retrospectively evaluated the signal intensities and enhancement features on MRI and MDCT.

RESULTS

None of the lesions displayed arterial enhancement and washout on MDCT. On Gd-EOB-MRI, six (32%) lesions showed T2-hyperintensity, five (26%) lesions showed signal drop on opposed-phase. Three lesions (16%) showed arterial enhancement and washout. Twelve (63%), 13 (68%), and 15 (79%) lesions were hypointense on hepatic venous, equilibrium, and hepatobiliary phase, respectively.

CONCLUSION

Most early HCCs did not show arterial enhancement and washout pattern on both MDCT and Gd-EOB-MRI. Gd-EOB-MRI may provide several ancillary findings for diagnosis of early HCC such as decreased hepatobiliary uptake, T2 hyperintensity and signal drop in opposed phase.

Proliferative activity in hepatocellular carcinoma is closely correlated with glucose metabolism but not angiogenesis

BACKGROUND & AIMS

This study investigated the relationship between tumor proliferative activity and the grade of tumor glucose metabolism or angiogenesis in hepatocellular carcinoma (HCC).

METHODS

The study was performed as a retrospective analysis of 63 patients with HCC who underwent fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) as a preoperative examination prior to liver resection. Tumor proliferative activity was evaluated by the Ki-67 labeling index (LI). The grade of tumor glucose metabolism was evaluated by measuring the protein expression level of glucose transporter (GLUT)-1, expression level of pyruvate kinase type M2 (PKM2) mRNA, and FDG uptake. The grade of tumor angiogenesis was evaluated by the protein expression level of vascular endothelial growth factor (VEGF) and tumor microvessel density.

RESULTS

All patients were divided into tertiles according to the Ki-67 LI: the low LI group (n = 21), the intermediate LI group (n = 21), and the high LI group (n = 21). The high LI group showed a tendency to have advanced tumor stage, and lower disease-free survival and overall survival rates than the low LI and the intermediate LI groups. The expression grade of GLUT-1, PKM2 mRNA, and FDG uptake gradually increased with the Ki-67 LI. On the other hand, the protein expression grade of VEGF and microvessel density was paradoxically decreased with the Ki-67 LI.

CONCLUSIONS

These data suggest that (1) the proliferative activity of a resected specimen predicted the prognosis in patients with HCC; (2) the proliferative activity was closely correlated with the glucose metabolism, but not with angiogenesis.

Gadoxetate disodium-enhanced hepatobiliary phase MRI of hepatocellular carcinoma: correlation with histological characteristics

OBJECTIVE

The purpose of this study was to assess whether gadoxetate disodium-enhanced hepatobiliary phase MRI could predict the histologic factors of hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

Fifty-three HCCs histopathologically proved by surgery in 51 patients were evaluated retrospectively. All patients underwent gadoxetate disodium-enhanced MRI before surgical resection. The differences in contrast enhancement ratio of the lesions and differences in contrast-to-noise ratio (CNR) among the histologic grades of HCC were compared by using the Kruskal-Wallis test. The Spearman method was used to determine the correlations among contrast enhancement ratio, CNR, cell density ratio, and positivity for anti-hepatocyte antibody, keratin 7, and keratin 19.

RESULTS

Of 53 HCCs, 50 showed low signal intensity on hepatobiliary phase images, whereas three HCCs were hyperintense on hepatobiliary phase images compared with surrounding hepatic parenchyma. Although well-differentiated HCCs tended to show higher contrast enhancement, there was no statistical significance between contrast enhancement ratio of the tumors and histologic grade (p = 0.414). No significant difference was observed between CNR and histologic grade (p = 0.965). The contrast enhancement ratios of the tumors were significantly lower in the keratin 19-positive group than in the keratin 19-negative group (p = 0.015). There was no significant correlation among contrast enhancement ratio, anti-hepatocyte antibody positivity, cell density ratio, and keratin 7 positivity (p > 0.05).

CONCLUSION

The contrast enhancement ratio and CNR of HCCs were not correlated with histologic grades. The contrast enhancement ratio was significantly lower in keratin 19-positive HCCs.

Evolution of hypointense hepatocellular nodules observed only in the hepatobiliary phase of gadoxetate disodium-enhanced MRI

OBJECTIVE

We sought to determine whether hypointense hepatocellular nodules observed in the hepatobiliary phase of MRI enhanced with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (gadoxetate disodium) progress to hypervascular hepatocellular carcinoma.

MATERIALS AND METHODS

Gadoxetate disodium-enhanced MRI was repeated for 30 patients with 49 nodules determined to be hypointense in the hepatobiliary phase but nonenhancing in the arterial phase of dynamic MRI. The correlation between characteristics of hypointense nodules with slightly or markedly low signal intensity relative to surrounding liver parenchyma and their progression to hypervascular hepatocellular carcinoma was analyzed in cirrhotic livers. All patients underwent angiography-assisted CT before MRI. The rate of progression to classic hepatocellular carcinoma was calculated by the Kaplan-Meier method.

RESULTS

The overall 6- and 12-month cumulative incidences of vascularization were 27.6% and 43.5%. The 6- and 12-month cumulative incidences of vascularized nodules with a maximum diameter 15 mm or greater were 43.3% and 77.3% and a maximum diameter less than 15 mm were 16.9% and 16.9%. The difference between these incidences was significant (p = 0.0147).

CONCLUSION

Hypointense nodules with a maximum diameter of at least 15 mm often become hypervascular. Therefore, patients with hypointense nodules characterized by a maximum diameter of 15 mm or greater should be observed carefully because of the high incidence of vascularization.

Uptake of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid in metastatic adrenal tumour from hepatocellular carcinoma

We present the case of a metastatic adrenal tumour from hepatocellular carcinoma (HCC) showing the uptake of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) on MRI. To our knowledge, this is the first case of metastatic HCC in which Gd-EOB-DTPA uptake was shown on MRI and this finding facilitated the accurate pre-operative diagnosis of a metastatic adrenal tumour.

Diagnostic efficacy of gadoxetic acid-enhanced MRI for hepatocellular carcinoma and dysplastic nodule

AIM: To evaluate the relationship between the signal intensity of hepatobiliary phase images on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and histological grade.

METHODS: Fifty-nine patients with 82 hepatocellular lesions were evaluated retrospectively. Hepatobiliary phase images on gadoxetic acid-enhanced MRI were classified into 3 groups: low, iso or high. Angiography-assisted computed tomography (CT) findings were also classified into 3 groups: CT during arterial portography, and CT hepatic arteriography: A: iso, iso or low; B: slightly low, iso or low; and C: low, high. We correlated angiography-assisted CT, hepatobiliary phase findings during gadoxetic acid-enhanced MRI and histological grades. Furthermore, correlations between MRI findings and histological grade for each hemodynamic pattern were performed. Correlations among radiological and pathological findings were statistically evaluated using the chi-square test and Fisher’ s exact test.

RESULTS: There was a significant correlation between histological grade and hemodynamic pattern (P < 0.05). There was a significant correlation between histological grade and signal intensity in the hepatobiliary phase (P < 0.05) in group A lesions. There was no significant correlation between histological grade and signal intensity in the hepatobiliary phase in group B or C lesions (P > 0.05).

CONCLUSION: Signal intensity in the hepatobiliary phase correlated with histological grade in the lesions that maintained portal blood flow, but did not correlate in lesions that showed decreased or defective portal blood flow.

Signal profile on Gd-EOB-DTPA-enhanced MR imaging in non-alcoholic steatohepatitis and liver cirrhosis induced in rats: correlation with transporter expression

OBJECTIVES

To compare the transporter expression and signal profile on Gd-EOB-DTPA-enhanced MRI between non-alcoholic steatohepatitis (NASH) and cirrhotic liver induced in rats, and investigate the correlation of the transporter expression and fibrosis rate in both diseases.

METHODS

Forty-eight rats were divided into four groups of 12: TAA (cirrhosis), NASH 7- and 10-week, and control groups. Each group was divided into two subgroups: Group 1 for MRI and Group 2 for transporter examinations.

RESULTS

The relative enhancement of the TAA group was significantly lower than those of other groups (p < 0.01). The T(max) and T(1/2) of the NASH 10-week group was significantly prolonged in comparison with the TAA group (p < 0.01). There was no significant difference in the oatp1 expression, whereas the mrp2 expression of the TAA group was significantly higher than those of other groups (p < 0.01). There was no significant correlation between the fibrosis rate and oatp1 expression, whereas a paradoxical correlation was found between the fibrosis rate and mrp2 expression (NASH: negative correlation, r = 0.91, p < 0.01; TAA: positive correlation, r = 0.85, p < 0.01).

CONCLUSIONS

Our findings showed that the mrp2 expression in cirrhosis increases in comparison with NASH, and there was a paradoxical correlation between the fibrosis rate and mrp2 expression.

Imaging of focal nodular hyperplastic-like nodules in alcoholic liver cirrhosis patients using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging

We report on two patients with a history of alcohol abuse who presented with multiple hepatic nodules. Dynamic computed tomography revealed multiple nodular lesions, which were enhanced at the early contrast phase and washed out at the portal phase. In the hepatobiliary phase using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging (Gd-EOB-DTPA MRI), these tumors did not show any uptake, thus suggesting the presence of hepatocellular carcinoma. An ultrasound-guided biopsy revealed a slight increase in cell density, sinusoidal dilatation, and contained unpaired small arteries. According to immunohistochemical analyses, these arteries were positive for CD34 and alpha-smooth muscle actin. From these findings, the nodules were diagnosed to be focal nodular hyperplastic (FNH)-like nodules arising in alcoholic-cirrhosed livers. The differential diagnosis of FNH-like nodules arising in alcoholic liver cirrhosis and hepatocellular carcinoma is difficult with Gd-EOB-DTPA MRI, and therefore histological confirmation is necessary.

Large regenerative nodules in a patient with Budd-Chiari syndrome after TIPS positioning while on the liver transplantation list diagnosed by Gd-EOB-DTPA MRI

BACKGROUND

Large regenerative nodules (LRNs) are hyperplastic benign nodules most commonly associated with Budd-Chiari syndrome (BCS), caused by outflow obstruction of the hepatic veins or vena cava. To our knowledge, no cases of LRNs arising in BCS after transjugular intrahepatic portosystemic shunt (TIPS) positioning and detected by Gd-EOB-DTPA MRI have been reported in the literature.

METHODS

A 58-year-old woman with BCS, on the liver transplantation (LT) list, underwent a follow-up enhanced MRI. Two years earlier, a TIPS had been placed. In 2008, recurrent hepaticoencephalopathy resistant to medical treatment fulfilled the LT criteria for BCS treated with TIPS and the patient was therefore added to the LT list. CT performed before TIPS had not detected any hepatic lesions. CT performed six months after TIPS showed its complete patency but documented two indeterminate hypervascular liver lesions.

RESULTS

MRI performed with Gd-EOB-DTPA revealed additional hypervascular lesions with uptake and retention of the medium in the hepatobiliary phase, thus reflecting a benign behavior of hepatocellular composition. These MRI features were related to LRNs as confirmed by histopathologic analysis.

CONCLUSIONS

Gd-EOB-DTPA-enhanced MRI is potentially superior to standard imaging using gadolinium chelates or spiral CT, especially for the differential diagnosis of hypervascular lesions. Gd-EOB-DTPA MRI may become the imaging method of choice for evaluating LT list patients with BCS after TIPS placement.

Consensus report of the 4th International Forum for Gadolinium-Ethoxybenzyl-Diethylenetriamine Pentaacetic Acid Magnetic Resonance Imaging

This paper reports on issues relating to the optimal use of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging (Gd-EOB-DTPA MR imaging) together with the generation of consensus statements from a working group meeting, which was held in Seoul, Korea (2010). Gd-EOB-DTPA has been shown to improve the detection and characterization of liver lesions, and the information provided by the hepatobiliary phase is proving particularly useful in differential diagnoses and in the characterization of small lesions (around 1-1.5 cm). Discussion also focused on advances in the role of organic anion-transporting polypeptide 8 (OATP8) transporters. Gd-EOB-DTPA is also emerging as a promising tool for functional analysis, enabling the calculation of post-surgical liver function in the remaining segments. Updates to current algorithms were also discussed.

Expression of SLCO1B3 is associated with intratumoral cholestasis and CTNNB1 mutations in hepatocellular carcinoma

Recent studies have shown that intratumoral cholestasis is a hallmark of CTNNB1 mutations in hepatocellular carcinomas (HCC). Here, we analyzed the expressions of genes involved in bile acid and bilirubin metabolism and their correlation with the mutational status of CTNNB1 in a series of HCC. The expressions of CYP7A1 and CYP27A1, which encode rate-limiting enzymes in bile acid synthesis, were unaltered or only marginally increased in CTNNB1-mutated HCC compared with those in HCC with wild-type CTNNB1. Among the genes involved in bile acid and bilirubin transport, the expression of SLCO1B3 was significantly elevated in HCC with CTNNB1 mutations, whereas the expression of ABCC4 was elevated in HCC with wild-type CTNNB1. Immunohistochemistry confirmed the frequent expression of SLCO1B3 in CTNNB1-mutated HCC at the protein level, but not in most HCC with wild-type CTNNB1. Immunohistochemistry for MRP4 (encoded by ABCC4) partly agreed with ABCC4 expression, but most cases did not express detectable levels of MRP4. Notably, all HCC with bile accumulation, including those without CTNNB1 mutations, expressed SLCO1B3, suggesting that SLCO1B3 expression, rather than CTNNB1 mutation, is the critical determinant of intratumoral cholestasis. As SLCO1B3 is involved in the uptake of a number of chemotherapeutic and diagnostic agents, SLCO1B3 expression and the status of CTNNB1 mutation might need to be considered in the drug delivery to HCC.

Recent advances in cytogenetics and molecular biology of adult hepatocellular tumors: implications for imaging and management

Focal nodular hyperplasia (FNH), hepatocellular adenoma (HCA), and hepatocellular carcinoma (HCC) compose hepatocellular neoplasms that occur in adults. These tumors demonstrate characteristic epidemiologic and histopathologic features and clinical and imaging manifestations. HCAs are monoclonal neoplasms characterized by increased predilection to hemorrhage or rupture and occasional transformation to HCC. On the other hand, FNH is a polyclonal tumorlike lesion that occurs in response to increased perfusion and has an indolent clinical course. Up to 90% of HCCs occur in the setting of cirrhosis. Chronic viral hepatitis (hepatitis B and hepatitis C) infection and metabolic syndrome are major risk factors that can induce HCCs in nonfibrotic liver. Recent advances in pathology and genetics have led to better understanding of the histogenesis, natural history, and molecular events that determine specific oncologic pathways used by these neoplasms. HCAs are now believed to result from specific genetic mutations involving TCF1 (transcription factor 1 gene), IL6ST (interleukin 6 signal transducer gene), and CTNNB1 (β catenin-1 gene); FNHs are characterized by an "imbalance" of angiopoietin. While the β catenin signaling pathway is associated with well- and moderately differentiated HCCs, mutations involving p53 (tumor protein 53 gene), MMP14 (matrix metalloproteinase 14 gene), and RhoC (Ras homolog gene family, member C) are associated with larger tumor size, higher tumor grade with resultant shortened tumor-free survival, and poor prognosis. Fibrolamellar carcinoma (FLC), a unique HCC subtype, exhibits genomic homogeneity that partly explains its better overall prognosis. On the basis of recent study results involving cytogenetics and oncologic pathways of HCCs, novel drugs that act against molecular targets are being developed. Indeed, sorafenib (a multikinase inhibitor) is currently being used in the successful treatment of patients with advanced HCC. Characterization of genetic abnormalities and genotype-phenotype correlations in adult hepatocellular tumors provides better understanding of tumor pathology and biology, imaging findings, prognosis, and response to molecular therapeutics.

The role of hepatocyte-specific staining in liver pathology

The advantages of MRI in the investigation of liver disease are well documented. Recent developments, including fast scanning technique and new MRI contrast agents, enable improved detection and characterization of focal liver lesions. Therefore, a definitive diagnosis can be made avoiding invasive procedures, such as liver biopsy. In this article, a special emphasis is placed on the clinical use of combined perfusional and hepatocyte-selective MRI contrast agents, which allow us to obtain morphologic and vascular information, owing to the dynamic study, as well as functional information, owing to the hepatocyte-selective phase of enhancement. Different clinical scenarios are considered in order to highlight the proper use of the hepatocyte phase to noninvasively characterize and detect different focal liver lesions.

The uptake transporter OATP8 expression decreases during multistep hepatocarcinogenesis: correlation with gadoxetic acid enhanced MR imaging

OBJECTIVES

To clarify the changes in organic anion-transporting polypeptide 8 (OATP8) expression and enhancement ratio on gadoxetic acid-enhanced MR imaging in hepatocellular nodules during multistep hepatocarcinogenesis.

METHODS

In imaging analysis, we focused on 71 surgically resected hepatocellular carcinomas (well, moderately and poorly differentiated HCCs) and 1 dysplastic nodule (DN). We examined the enhancement ratio in the hepatobiliary phase of gadoxetic acid enhanced MR imaging [(1/postcontrast T1 value-1/precontrast T1 value)/(1/precontrast T1 value)], then analysed the correlation among the enhancement ratio, tumour differentiation grade and intensity of immunohistochemical OATP8 expression. In pathological analysis, we focused on surgically resected 190 hepatocellular nodules: low-grade DNs, high-grade DNs, early HCCs, well-differentiated, moderately differentiated and poorly differentiated HCCs, including cases without gadoxetic acid-enhanced MR imaging. We evaluated the correlation between the immunohistochemical OATP8 expression and the tumour differentiation grade.

RESULTS

The enhancement ratio of HCCs decreased in accordance with the decline in tumour differentiation (P < 0.0001, R = 0.28) and with the decline of OATP8 expression (P < 0.0001, R = 0.81). The immunohistochemical OATP8 expression decreased from low-grade DNs to poorly differentiated HCCs (P < 0.0001, R = 0.15).

CONCLUSIONS

The immunohistochemical expression of OATP8 significantly decreases during multistep hepatocarcinogenesis, which may explain the decrease in enhancement ratio on gadoxetic acid-enhanced MR imaging.

Evaluation of possible drug-drug interaction between gadoxetic acid and erythromycin as an inhibitor of organic anion transporting peptides (OATP)

PURPOSE

To evaluate if erythromycin compromises liver-specific enhancement of gadoxetic acid; both compounds competing in organic anion transporting peptides (OATP) -mediated hepatocytic uptake.

MATERIALS AND METHODS

The study was approved by institutional review board. Twelve healthy subjects (nine men, three woman; mean age, 38.7 years) were examined twice by MR imaging with prior administration of NaCl solution (placebo) or 1000 mg of erythromycin following a randomized sequence. Gadoxetic acid (0.025 mmol/kg body weight) was administered 15 min after the end of infusions. Pre- and 20 min postcontrast two-dimensional gradient-recalled-echo sequences were acquired. Relative enhancements of liver parenchyma and ratio of means were calculated from signal intensity measurements. Plasma levels of gadoxetic acid and erythromycin were determined and given in geometric means and coefficients of variation (CV).

RESULTS

Concentration of erythromycin directly after end of infusion was 13.9 mg/L (CV 14.9%). Gadolinium plasma concentrations 5 min after gadoxetic acid administration were 138.7 μmol/L (CV 20.4%) after erythromycin infusion and 129.6 μmol/L (CV 22.8%) after placebo. Mean relative enhancements of liver parenchyma were 88.1 (SD 24.9%) after erythromycin infusion and 92.6 (SD 17.9%) after placebo. Ratio of relative enhancements was 0.951 (95% confidence interval, 0.833; 1.061; statistically not significant).

CONCLUSION

Coadministration of erythromycin has no effect on gadoxetic acid enhanced liver MR imaging.