Effect of change in transporter expression on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging during hepatocarcinogenesis in rats

Evaluation of liver function using Gd-EOB-DTPA-enhanced MRI with T1 mapping

PURPOSE

To evaluate the value of MRI T1 mapping with Gd-EOB-DTPA for assessing liver function.

METHODS

Seventy-two patients who underwent Gd-EOB-DTPA-enhanced MRI for focal liver lesions at Beijing Friendship Hospital from August 2020 to March 2022 were prospectively enrolled, and variable-flip-angle T1 mapping was performed before and 20 min after enhancement. The Child-Pugh (C-P) score and albumin-bilirubin (ALBI) grade of liver function were assessed using the clinical data of the patients. Correlation analysis was used to evaluate the correlation between T1 mapping parameters and liver function grading and laboratory tests. Nonparametric tests were used to compare the differences among different liver function groups. The liver function classification efficiency of each image index was evaluated with receiver operating characteristic (ROC) curves.

RESULTS

T1post was positively correlated with the C-P grade and the ALBI grade (r = 0.717 and r = 0.652). ΔT1 was negatively correlated with the C-P grade and the ALBI grade (r = -0.790 and r = -0.658). T1post and ΔT1 significantly differed among different liver function grades (p < 0.05). For the C-P grade, T1post and ΔT1 were significantly different between each pair of groups (p < 0.05), and ΔT1 had a better diagnostic efficiency than T1post. For the ALBI grade, ΔT1 and T1post were significantly different between the NLF and ALBI1 groups (p < 0.05), and ΔT1 had a better diagnostic efficacy than T1post. T1post significantly differed between the ALBI1 and ALBI2 + 3 groups (p < 0.05), while ΔT1 had a weak ability to differentiate between these two groups.

CONCLUSION

T1post and ΔT1 were strongly correlated with the two liver function grades and can be noninvasive imaging indexes for evaluating liver function.

A gadoxetic-acid enhancement flux analysis of small liver nodules (≤2 cm) in patients at high risk of hepatocellular carcinoma

PURPOSE

To discriminate between benignities and hepatocellular carcinomas (HCCs) in patients at high risk of HCC using a novel enhancement flux analysis for gadoxetic-acid enhanced MRI.

METHOD

This study retrospectively collected 181 liver nodules in 156 patients at high risk of HCC who underwent gadoxetic acid-enhanced MRI examinations with following surgical resection from 1st August 2017 to 31st December 2021 as the training set; another 42 liver nodules in 36 patients were prospectively collected from 1st January 2022 to 1st October 2022 as the test set. The time-intensity curves (TICs) of liver nodules were formed with consecutive time points: 0 s, 20 s, 1 min, 2 min, 5 min, 10 min, 15 min, and 20 min since contrast injection. A novel enhancement flux analysis was applied by using a biexponential function fitting to distinguish benignities and HCC. Besides, previously published models including maximum enhancement ratio (ER_max), percentage signal ratio (PSR), and ER_max+PSR were compared. The areas under the receiver operating characteristic curves (AUCs) were compared among these methods.

RESULTS

The novel enhancement flux analysis showed the highest AUCs in the training set (0.897, 95%CI: 0.833-0.960) and the test set (0.859, 95%CI: 0.747-0.970) among all models. The AUCs of PSR, ER_max and ER_max+PSR were 0.801 (95%CI: 0.710-0.891), 0.620 (95%CI: 0.510-0.729), and 0.799 (95%CI: 0.709-0.889) in the training set, and were 0.701 (95%CI: 0.539-0.863), 0.529 (95%CI: 0.342-0.717), and 0.708 (95%CI: 0.549-0.867) in the test set.

CONCLUSIONS

The biexponential flux analysis for gadoxetic-acid enhanced MRI presents a better potential in accurate diagnosis of small HCC nodules.

Carvacrol enhances anti-tumor activity and mitigates cardiotoxicity of sorafenib in thioacetamide-induced hepatocellular carcinoma model through inhibiting TRPM7

AIMS

Sorafenib (Sora) represents one of the few effective drugs for the treatment of advanced hepatocellular carcinoma (HCC), while resistance and cardiotoxicity limit its therapeutic efficacy. This study investigated the effect of transient receptor potential melastatin 7 (TRPM7) inhibitor, carvacrol (CARV), on overcoming Sora resistance and cardiotoxicity in thioacetamide (TAA) induced HCC in rats.

MATERIALS AND METHODS

TAA (200 mg/kg/twice weekly, intraperitoneal) was administered for 16 weeks to induce HCC. Rats were treated with Sora (10 mg/Kg/day; orally) and CARV (15 mg/kg/day; orally) alone or in combination, for six weeks after HCC induction. Liver and heart functions, antioxidant capacity, and histopathology were performed. Apoptosis, proliferation, angiogenesis, metastasis, and drug resistance were assessed by quantitative real time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry.

KEY FINDINGS

CARV/Sora combination significantly improved survival rate, and liver functions, reduced Alpha-Fetoprotein level, and attenuated HCC progression compared with Sora group. CARV coadministration almost obviated Sora-induced changes in cardiac and hepatic tissues. The CARV/Sora combination suppressed drug resistance and stemness by downregulating ATP-binding cassette subfamily G member 2, NOTCH1, Spalt like transcription factor 4, and CD133. CARV boosted Sora antiproliferative and apoptotic activities by decreasing cyclin D1 and B-cell leukemia/lymphoma 2 and increasing BCL2-Associated X and caspase-3.

SIGNIFICANCE

CARV/Sora is a promising combination for tumor suppression and overcoming Sora resistance and cardiotoxicity in HCC by modulating TRPM7. To our best knowledge, this study represents the first study to investigate the efficiency of CARV/ Sora on the HCC rat model. Moreover, no previous studies have reported the effect of inhibiting TRPM7 on HCC.

Gadoxetic Acid-Enhanced MRI Features for Predicting Treatment Outcomes of Early Hepatocellular Carcinoma (< 3 cm) After Transarterial Chemoembolization

RATIONALE AND OBJECTIVES

Magnetic resonance imaging (MRI) is the most useful imaging tool for small hepatocellular carcinoma (HCC) evaluation. Patients undergoing transarterial chemoembolization (TACE) might have predictive imaging prognostic factors. This study aimed to find predictive gadoxetic acid (GA)-enhanced MRI features that affect tumor response and outcomes in patients with early HCC who underwent conventional TACE.

MATERIALS AND METHODS

Among patients who underwent conventional TACE as a first-line treatment for Barcelona clinic liver cancer stage 0 or A (<3 cm), 135 patients who underwent GA-enhanced MRI before treatment were included in this retrospective study. The patients' pretreatment clinical characteristics and MRI features were evaluated. Post-treatment tumor response, progression-free survival (PFS), and overall survival (OS) were also investigated.

RESULTS

The median follow-up period was 47 (range: 7-133) months, with 90 (67%) patients showing complete remission (CR) at the 1-month follow-up after TACE. Tumor number (odds ratio [OR] 0.602, 95% confidence interval [CI]: 0.375-0.967), central location (OR: 0.349, 95% CI: 0.145-0.837) were inversely associated with CR achievement. Median PFS and OS time were 22 (range: 1-133) and 67 (range: 7-133) months, respectively. The MRI features affecting poor survival outcomes were tumor number (PFS: hazard ratio [HR]=1.444, 95% CI=1.124-1.854; OS: HR=1.459, 95% CI=1.018-2.090), central location (PFS: HR=1.664, 95% CI=1.038-2.667; OS: HR=1.890, 95% CI=1.021-3.497), and marginal irregularity (PFS: HR=3.099, 95% CI=1.953-4.979; OS: HR=1.985, 95% CI=1.084-3.634).

CONCLUSION

Multiplicity, central location, and marginal irregularity of HCC on GA-enhanced MRI were significant factors associated with poor prognosis of patients with early HCC after conventional TACE.

Quantitative evaluation of hepatic fibrosis by fibro Scan and Gd-EOB-DTPA-enhanced T1 mapping magnetic resonance imaging in chronic hepatitis B

PURPOSE

Studies have found that both FibroScan (FS) and Gd-EOB-DTPA-enhanced T1 mapping magnetic resonance imaging (Gd-MRI) could assess liver fibrosis (LF) with high effectiveness. The aim of this study is to compare their accuracy in the quantitative evaluation of LF in patients with chronic hepatitis B (CHB), and to explore the diagnostic accuracy of their combination.

METHODS

160 patients with CHB were included in this study. FS and Gd-MRI were performed within 3 months before the pathological LF staging, which was classified according to the Scheuer-Ludwig scale. The liver stiffness measurement (LSM) was obtained by FS. T1 mapping images of the liver before and 20 min after enhancement were obtained by Look-Locker Gd-MRI.

RESULTS

There were 45, 35, 31 and 49 patients with stage S1, S2, S3 and S4 LF, respectively. LSM increased and the reduction rate of T1 relaxation time of 20 min (rrT1_20min%) decreased with the severity of LF. The area under curve (AUC) of LSM, rrT1_20min% and LSM + rrT1_20min% for the diagnosis of ≥ S2 LF were 0.892, 0.811 and 0.900, respectively. The AUC for ≥ S3 LF was 0.883, 0.838 and 0.899, respectively. The AUC for S4 LF was 0.882, 0.894 and 0.928, respectively.

CONCLUSION

The diagnostic accuracy of FS is better than that of Gd-MRI in the evaluation of ≥ S2 stage LF. The combination of these two methods significantly improved the diagnostic efficiency in the evaluation of S4 stage LF.

Evaluation of liver function in patients with chronic hepatitis B using Gd-EOB-DTPA-enhanced T1 mapping at different acquisition time points: a feasibility study

PURPOSE

This study aimed to explore the impact of different acquisition times on the evaluation of liver function levels in chronic hepatitis B using Gd-EOB-DTPA-enhanced T1 positioning technology under 3.0 Tesla magnetic resonance imaging (MRI).

METHODS

A total of 146 patients with chronic hepatitis B (CHB) were classified into four groups as follows: chronic hepatitis B without liver cirrhosis (CH, 22 cases), liver cirrhosis with Child-Pugh classification A (LCA 63 cases), Child-Pugh B (LCB 47 cases) and Child-Pugh C (LCC 14 cases). Normal liver function (NLF) group was composed of 23 persons who had healthy liver and no medical histories of hepatitis. T1 mapping images were performed before and after administration of Gd-EOB-DPTA using Look-Locker sequence. Changes in T1 relaxation time (T1rt), the reduction rate of T1 relaxation time (ΔT1) and the increase in T1 relaxation rate (ΔR1) of liver over time (at 5, 10, 15 and 20 min) were investigated and compared among all five groups using a one-way analysis of variance (ANOVA). The Spearman's rank correlation coefficient (r) was used to show the correlations of these parameters in different liver function groups.

RESULTS

In the NLF, CH, LCA and LCB groups, postT1 gradually decreased, while the ΔT1 and ΔR1 gradually increased with time. The parameters were compared between different liver function levels at the same time point, and the differences were statistically significant except for NLF-CH, NLF-LCA and CH-LCA. There was no significant difference in the area under the ROC curve of other parameters at 10, 15 and 20 min. At each time point, no correlation was found between preT1rt and the degrees of liver function. PostT1rt was positively correlated with liver function classification, while ΔT1 and ΔR1 were negatively correlated with liver function classification.

CONCLUSION

Gd-EOB-DTPA-enhanced T1 mapping magnetic resonance imaging is beneficial to assess liver function. Using the Gd-EOB-DTPA to enhance T1 mapping imaging to assess liver function can shorten the observation time of the hepatobiliary period and 10 min after enhancement may be the best time point.

Preliminary clinical study of the safety of hepatectomy predicted by gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced T1 mapping magnetic resonance imaging

Background and Aim

Studies have found that gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced T1 mapping magnetic resonance imaging (MRI) could assess liver fibrosis, cirrhosis, and function with high effectiveness. The aim of this study is to explore the efficacy of MRI in predicting the safety of hepatectomy.

Methods

Forty-nine patients who underwent liver resection were recruited. Gd-EOB-DTPA-enhanced MRI examination was performed 1 week before surgery, and the rate of T1 relaxation time reduction (ΔT1_20min%) of liver parenchyma was calculated. Posthepatectomy liver failure (PHLF) was defined by the "50-50 criteria" and International Study Group of Liver Surgery (ISGLS) classification, respectively, and posthepatectomy complications (PHC) were defined by the Clavien-Dindo grading system. The effectiveness of ΔT1_20min% in predicting the occurrence of PHLF and PHC was analyzed.

Results

The area under the curve (AUC) for ΔT1_20min% predicting PHLF meeting "50-50 criteria" was 0.957, with a cutoff value of 0.497, sensitivity of 100%, and specificity of 89.1%. The AUC for predicting ISGLS grade B/C (severe) PHLF was 0.84, with a cutoff value of 0.5232, sensitivity of 63.6%, and specificity of 92.6%. The AUC for predicting PHC of Clavien-Dindo grades 3-5 (severe) was 0.882, with a cutoff value of 0.5646, sensitivity of 87.5%, and specificity of 75.8%. Univariate and multivariate analyses showed that ΔT1_20min% < 0.4970 (P < 0.01) was an independent risk factor for the development of PHLF (50-50 criteria). Univariate and multivariate analyses showed that liver stiffness measurement and ΔT1_20min% were risk factors for severe PHLF and severe PHC.

Conclusions

Gd-EOB-DTPA-enhanced T1 mapping MRI accurately predicts the safety of hepatectomy.

Quantitative Evaluation of Liver Fibrosis on T1 Relaxometry in Comparison with Fibroscan

Purpose

This study was performed to determine whether the T1 relaxation time of gadoxetic acid-enhanced liver MR imaging is useful for detecting and staging liver fibrosis in patients with chronic liver disease.

Materials and Methods

One hundred and three patients with suspected focal liver lesion underwent MR imaging and Fibroscan. Fibroscan was chosen as the reference standard for classifying liver fibrosis. T1 relaxation times were acquired before (preT1), 20 minutes after (postT1) contrast administration, and reduction rate of T1 relaxation time (rrT1) on transverse 3D VIBE (volumetric interpolated breath-hold examination) sequence using 3T MR imaging. The optimal cut-off values for the fibrosis staging were determined with ROC analysis.

Results

PreT1 and postT1 increased and rrT1 decreased constantly with increasing severity of liver fibrosis according to the METAVIR score (F0–F4). There were statistically significant differences between F2 and F3 in preT1 (F2, 836.0 ± 74.7 ms; F3, 888.6 ± 77.5 ms, p < 0.05) and between F3 and F4 in postT1 (F3, 309.0 ± 80.2 ms; F4, 406.6 ± 147.7 ms, p < 0.05) and rrT1 (F3, 65.4 ± 7.7%; F4, 57.3 ± 11.4%, p < 0.05). ROC analysis revealed that combination test (preT1 + postT1) was the best test for predicting liver fibrosis.

Conclusion

PreT1 and postT1 increased constantly with increasing severity of liver fibrosis. T1 mapping in gadoxetic acid-enhanced liver MR imaging could be a helpful complementary sequence to determine the liver fibrosis stage.

Synthesis and Evaluation of Manganese(II)-Based Ethylenediaminetetraacetic Acid-Ethoxybenzyl Conjugate as a Highly Stable Hepatobiliary Magnetic Resonance Imaging Contrast Agent

In this study, we designed and synthesized a highly stable manganese (Mn²⁺)-based hepatobiliary complex by tethering an ethoxybenzyl (EOB) moiety with an ethylenediaminetetraacetic acid (EDTA) coordination cage as an alternative to the well-established hepatobiliary gadolinium (Gd³⁺) chelates and evaluated its usage as a T₁ hepatobiliary magnetic resonance imaging (MRI) contrast agent (CA). This new complex exhibits higher r₁ relaxivity (2.3 mM^-1 s^-1) than clinically approved Mn²⁺-based hepatobiliary complex Mn-DPDP (1.6 mM^-1 s^-1) at 1.5 T. Mn-EDTA-EOB shows much higher kinetic inertness than that of clinically approved Gd³⁺-based hepatobiliary MRI CAs, such as Gd-DTPA-EOB and Gd-BOPTA. In addition, in vivo biodistribution and MRI enhancement patterns of this new Mn²⁺ chelate are comparable to those of Gd³⁺-based hepatobiliary MRI CAs. The diagnostic efficacy of the new complex was demonstrated by its enhanced tumor detection sensitivity in a liver cancer model using in vivo MRI.

Effects of Hepatic Ischemia-Reperfusion Injuries and NRF2 on Transcriptional Activities of Bile Transporters in Rats

BACKGROUND

The effect of hepatic ischemia-reperfusion injury (IRI) on bile transporter (BT) gene expression is unknown. We hypothesized that abnormal expression of BTs during hepatic IRI is dependent on nuclear factor erythroid 2-related factor 2 (NRF2), which contributes to the cholestasis after reperfusion.

METHODS

Sham surgery and short (60 min) or long (90 min) periods of warm ischemia time (WIT) with or without reperfusion for 24 h were applied to wild-type Sprague-Dawley rats and Nrf2 knockout rats (n = 5 per group). At each stage of IRI, the serum levels of aminotransferase, total bilirubin, and bile acids were measured. In addition, hepatic tissue was sampled to determine the histologic score of IRI (Suzuki score), measure adenosine triphosphate (ATP), and identify the quantitative real-time polymerase chain reactions of BTs (Oatp1, Ntcp, Mrp2, Bsep, and Mrp3).

RESULTS

In short periods of WIT, BT expression increased during the ischemia stage and returned to the baseline after reperfusion. However, in long periods of WIT, BT expression did not increase after ischemia and decreased further after reperfusion. Short WIT did not increase BT expression in Nrf2 knockout animals. The level of BT expression was correlated with the Suzuki score, the serum levels of aminotransferase, bilirubin, and bile acids, and tissue ATP level. Stepwise multiple regression analysis derived equations to predict the Suzuki score (R² = 76.8, P < 0.001), serum total bilirubin (R² = 61.2, P < 0.001), and tissue ATP (R² = 61.1, P < 0.001).

CONCLUSIONS

Short WIT induces the transcriptional activities of BT, whereas long WIT depresses them, and the effect was blunted by Nrf2 knockout status. BT expression can be considered a surrogate marker for hepatic IRI.

A New Model for MR Evaluation of Liver Function with Gadoxetic Acid, Including Both Uptake and Excretion

OBJECTIVES

Most existing models that are in use to model hepatic function through assessment of hepatic gadoxetic acid enhancement kinetics do not consider quantitative measures of gadoxetic excretion. We developed a model that allows a simultaneous quantitation of uptake and excretion of liver specific contrast agents. The aim was to improve the assessment of hepatic synthetic function, and provide quantitative measures of hepatic excretion function.

METHODS

Sixteen patients underwent dynamic T1-weighted turbo gradient echo imaging at 1.5 T prior and after bolus injection of gadoxetic acid at 0.1 ml/kg. DCE-images were obtained for 30 min after injection. A dual-inlet two-compartment model was then used to fit the measured liver signal values. Four tissue parameters (extracellular volume fraction, arterial flow fraction, uptake rate and excretion half-time) were extracted for each liver segment.

RESULTS

The proposed model provided a good fit to acquired data. Mean values for arterial flow fraction (0.08+-0.04), extracellular volume (0.20±0.08) and uptake rate (4.02 ±1.32 /100 ml/min) were comparable to those obtained with the conventional model (0.08±0.05, 0.21±0.12, and 4.93±1.74), but exhibited significantly less variation and improved fit quality.

CONCLUSIONS

The proposed model is more accurate than existing conventional models and provides an additional excretion parameter.

KEY POINTS

• Models of hepatic contrast agent uptake can be extended to include excretion. • Including an additional excretion parameter improves accuracy of the model. • Standard diagnostic sequences can be extended to incorporate the model.

Major and ancillary magnetic resonance features of LI-RADS to assess HCC: an overview and update

Liver Imaging Reporting and Data System (LI-RADS) is a system for interpreting and reporting of imaging features on multidetector computed tomography (MDCT) and magnetic resonance (MR) studies in patients at risk for hepatocellular carcinoma (HCC). American College of Radiology (ACR) sustained the spread of LI-RADS to homogenizing the interpreting and reporting data of HCC patients. Diagnosis of HCC is due to the presence of major imaging features. Major features are imaging data used to categorize LI-RADS-3, LI-RADS-4, and LI-RADS-5 and include arterial-phase hyperenhancement, tumor diameter, washout appearance, capsule appearance and threshold growth. Ancillary are features that can be used to modify the LI-RADS classification. Ancillary features supporting malignancy (diffusion restriction, moderate T2 hyperintensity, T1 hypointensity on hapatospecifc phase) can be used to upgrade category by one or more categories, but not beyond LI-RADS-4. Our purpose is reporting an overview and update of major and ancillary MR imaging features in assessment of HCC.

Gd-EOB-DTPA based magnetic resonance imaging for predicting liver response to portal vein embolization

AIM

To evaluate the correlation between degree of kinetic growth (kGR) of the liver following portal vein embolization (PVE) liver and the enhancement of the during the hepatobiliary phase of contrast administration and to evaluate if the enhancement can be used to predict response to PVE prior to the procedure.

METHODS

Seventeen patients were consented for the prospective study. All patients had an MR of the abdomen with Gd-EOB-DTPA. Fourteen patients underwent PVE. The correlation between the kGR of the liver and the degree of enhancement was evaluated with linear regression (strong assumptions) and Spearman’s correlation test (rank based, no assumptions). The correlation was examined for the whole liver, segments I, VIII, VII, VI, V, IV, right liver and left liver.

RESULTS

There was no correlation between the degree of enhancement during the hepatobiliary phase and kGR for any segment, lobe of the liver or whole liver (P = 0.19 to 0.91 by Spearman’s correlation test).

CONCLUSION

The relative enhancement of the liver during the hepatobiliary phase with Gd-EOB-DTPA cannot be used to predict the liver response to PVE.

Gd-EOB-DTPA-enhanced MR relaxometry for the detection and staging of liver fibrosis

Gd-EOB-DTPA, a liver-specific contrast agent with T1-shortening effects, is routinely used in clinical routine for detection and characterization of focal liver lesions and has recently received increasing attention as a tool for the quantitative analyses of liver function. We report the relationship between the extent of Gd-EOB-DTPA- induced T1 relaxation and the degree of liver fibrosis, which was assessed according to the METAVIR score. For the T1 relaxometry, a transverse 3D VIBE sequence with inline T1 calculation was acquired prior to and 20 minutes after Gd-EOB-DTPA administration. The reduction rates of the T1 relaxation time (rrT1) between the pre- and postcontrast images were calculated, and the optimal cutoff values for the fibrosis stages were determined with receiver operating characteristic (ROC) curve analyses. The rrT1 decreased with the severity of liver fibrosis and regression analysis revealed a significant correlation of the rrT1 with the stage of liver fibrosis (r = -0.906, p < 0.001). ROC analysis revealed sensitivities ≥78% and specificities ≥94% for the differentiation of different fibrosis stages. Gd-EOB-DTPA-enhanced T1 relaxometry is a reliable tool for both the detection of initial hepatic fibrosis and the staging of hepatic fibrosis.

Pre-Hepatectomy Assessment of Bile Transporter Expression by Gadoxetic Acid-Enhanced MRI in a Rat Model of Liver Cirrhosis

BACKGROUND

Gadoxetic acid is a liver-specific intravenous T1 magnetic resonance (MR) contrast agent that is excreted via the hepatobiliary system. We hypothesize that hepatocyte expressions of bile transporters (OATP1 and MRP2) correlate with dynamic profile of Gadoxetic acid enhanced (GE)-MR imaging (MRI).

METHODS

Two groups of rats, control (n = 6) and cirrhosis (n = 12), received gadoxetic acid enhanced MRI followed by 70% hepatectomy. The change in MR signal intensity from the baseline before the contrast injection (ΔSI) was analyzed every minute for 30 min. Dynamic signal intensity retention ratio (DSR) was defined as the mean ΔSI of the third 10-minmin period divided by the first 10-minmin period. Real-time PCR was utilized to quantify mRNA expressions.

RESULTS

Compared to the control, cirrhosis group demonstrated lower mRNA levels of OATP1 (0.038 ± 0.020 vs. 0.232 ± 0.0979; p = 0.004), MRP2 (0.201 ± 0.084 vs. 0.7567 ± 0.254; p = 0.002), and OATP1/MRP2 mRNA ratio (0.193 ± 0.065 vs. 0.342 ± 0.206; p = 0.032). DSR was higher in the cirrhosis group (0.678 ± 0.554 vs -0.125 ± 0.839; p = 0.033). In the cirrhosis group, there was an inverse correlation between the ratios of OATP1/MRP2 mRNA and DSR (R = -0.709, p = 0.01).

CONCLUSION

Bile transporters OATP1/MRP2 mRNA expression ratio in rat liver tissue decreased with DMN-induced liver injury. The expressions of bile transporters correlated with GE-MRI DSR. The GE-MRI DSR has potential utility in qualifying OATP1/MRP2 mRNA expression.

Gd-EOB-DTPA-enhanced-MR imaging in the inflammation stage of nonalcoholic steatohepatitis (NASH) in mice

OBJECTIVE

The purpose of this study is to investigate the correlation between the liver kinetics of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) and liver histopathology in a mouse model of NASH by using dynamic contrast-enhanced MRI.

MATERIALS AND METHODS

Twenty male C57/BL6 mice aged 8weeks were fed a methionine-choline-deficient (MCD) diet for 2, 4 and 6weeks (MCD groups: MCD 2w, 4w, or 6w). Gd-EOB-DTPA-enhanced MR imaging of the liver was performed at 2, 4 and 6weeks after the MCD feeding. The signal intensity of the liver was obtained from dynamic MR images and relative enhancement (RE), and the time to maximum RE (Tmax) and half-life of elimination RE (T1/2) were calculated. After MRI scan, histopathological scores of hepatic steatosis and inflammation and blood biochemistry data, such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, were obtained.

RESULTS

Plasma AST and ALT levels were significantly increased in mice fed MCD. Histopathological scores indicated that steatohepatitis progressed with the MCD feeding period from 2 to 6weeks, but significant fibrosis was observed only in mice fed MCD for 6weeks. Gd-EOB-DTPA-enhanced MRI showed that Tmax was significantly prolonged in the livers of the 6-week group compared to the control group (control, 4.0±0.7min; MCD 6w, 12.1±1.6min), although there was no alteration in the 2- and 4-week groups. T1/2 was significantly prolonged in mice fed MCD for 4 and 6weeks compared to the control group (control, 19.9±2.0min; MCD 4w, 46.7±8.7min; MCD 6w, 65.4±8.8min). The parameters of Gd-EOB-DTPA kinetics (Tmax and T1/2) in the liver were positively correlated with the liver histopathological score (steatosis vs Tmax, rho=0.69, P=0.0007; inflammation vs Tmax, rho=0.66, P=0.00155; steatosis vs T1/2, rho=0.77, P<0.0001; inflammation vs T1/2, rho=0.73, P=0.0003).

CONCLUSIONS

The liver kinetics of Gd-EOB-DTPA correlated well with the inflammation score in the mouse model of NASH, suggesting the possibility of detecting the steatohepatitis stage without fibrosis by Gd-EOB-DTPA-enhanced MR imaging.

MRI features of hepatocellular carcinoma related to biologic behavior

Imaging studies including magnetic resonance imaging (MRI) play a crucial role in the diagnosis and staging of hepatocellular carcinoma (HCC). Several recent studies reveal a large number of MRI features related to the prognosis of HCC. In this review, we discuss various MRI features of HCC and their implications for the diagnosis and prognosis as imaging biomarkers. As a whole, the favorable MRI findings of HCC are small size, encapsulation, intralesional fat, high apparent diffusion coefficient (ADC) value, and smooth margins or hyperintensity on the hepatobiliary phase of gadoxetic acid-enhanced MRI. Unfavorable findings include large size, multifocality, low ADC value, non-smooth margins or hypointensity on hepatobiliary phase images. MRI findings are potential imaging biomarkers in patients with HCC.

Non-hypervascular hypointense nodules ≥1 cm on the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging in cirrhotic livers

OBJECTIVE

To determine the pathologic nature of non-hypervascular hypointense nodules (≥1 cm) on the hepatobiliary phase (HBP) of gadoxetic acid-enhanced magnetic resonance (MR) imaging and to describe the chronological changes of their imaging features on follow-up MR imaging.

PATIENTS AND METHODS

This retrospective study was approved by our Institutional Review Board and the requirement for informed consent was waived. 69 patients with 115 non-hypervascular HBP hypointense nodules (≥1 cm in diameter) in cirrhotic livers were enrolled. 67 nodules were histologically diagnosed (group 1) and 52 nodules were followed up with MR for at least 12 months (group 2); 4 nodules belonged to both groups. Two radiologists reviewed the initial and follow-up MR images to determine the size and signal intensities on unenhanced T1- and T2-weighted images, dynamic phases and HBP images in consensus. In addition, two pathologists reviewed the histologic findings including H&E staining and four kinds of immunohistochemical staining in group 1.

RESULTS

In group 1, 73.1% (49/67) of nodules were hepatocellular carcinomas. In group 2, 32.7% (17/52) of nodules developed arterial hypervascularity on follow-up, and 78.8% (41/52) showed at least one of the three imaging features considered to indicate malignant changes during follow-up (mean 19 ± 10 months): increase in diameter by ≥5 mm (23/52, 44.2%), arterialization (17/52, 32.7%) and hyperintensity on T2-weighted images (18/52, 34.6%).

CONCLUSION

Our study results demonstrate that a significant proportion of non-hypervascular HBP hypointense nodules (≥1 cm in diameter) in patients with cirrhosis showed either malignant features on pathology (73.1%) or developed hypervascularity (32.7%) during follow-up.

CT and MR imaging diagnosis and staging of hepatocellular carcinoma: part I. Development, growth, and spread: key pathologic and imaging aspects

Computed tomography (CT) and magnetic resonance (MR) imaging play critical roles in the diagnosis and staging of hepatocellular carcinoma (HCC). The first article of this two-part review discusses key concepts of HCC development, growth, and spread, emphasizing those features with imaging correlates and hence most relevant to radiologists; state-of-the-art CT and MR imaging technique with extracellular and hepatobiliary contrast agents; and the imaging appearance of precursor nodules that eventually may transform into overt HCC.

MRI-based estimation of liver function: Gd-EOB-DTPA-enhanced T1 relaxometry of 3T vs. the MELD score

Gd-EOB-DTPA is a hepatocyte-specific MRI contrast agent. Due to its hepatocyte-specific uptake and paramagnetic properties, functioning areas of the liver exhibit shortening of the T1 relaxation time. We report the potential use of T1 relaxometry of the liver with Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for estimating the liver function as expressed by the MELD score. 3 T MRI relaxometry was performed before and 20 min after Gd-EOB-DTPA administration. A strong correlation between changes in the T1 relaxometry and the extent of liver disease, expressed by the MELD score, was documented. Reduced liver function correlates with decreased Gd-EOB-DTPA accumulation in the hepatocytes during the hepatobiliary phase. MRI-based T1 relaxometry with Gd-EOB-DTPA may be a useful method for assessing overall and segmental liver function.

Assessment of clinical signs of liver cirrhosis using T1 mapping on Gd-EOB-DTPA-enhanced 3T MRI

OBJECTIVES

To assess the differences between normal and cirrhotic livers by means of T1 mapping of liver parenchyma on gadoxetic acid (Gd-EOB-DTPA)-enhanced 3 Tesla (3T) MR imaging (MRI).

METHODS

162 patients with normal (n = 96) and cirrhotic livers (n = 66; Child-Pugh class A, n = 30; B, n = 28; C, n = 8) underwent Gd-EOB-DTPA-enhanced 3T MRI. To obtain T1 maps, two TurboFLASH sequences (TI = 400 ms and 1000 ms) before and 20 min after Gd-EOB-DTPA administration were acquired. T1 relaxation times of the liver and the reduction rate between pre- and post-contrast enhancement images were measured.

RESULTS

The T1 relaxation times for Gd-EOB-DTPA-enhanced MRI showed significant differences between patients with normal liver function and patients with Child-Pugh class A, B, and C (p < 0.001). The T1 relaxation times showed a constant significant increase from Child-Pugh class A up to class C (Child-Pugh class A, 335 ms ± 80 ms; B, 431 ms ± 75 ms; C, 557 ms ± 99 ms; Child-Pugh A to B, p < 0.001; Child-Pugh A to C, p < 0.001; Child-Pugh B to C, p < 0.001) and a constant decrease of the reduction rate of T1 relaxation times (Child-Pugh class A, 57.1% ± 8.8%; B, 44.3% ± 10.2%, C, 29.9% ± 6.9%; Child-Pugh A to B, p < 0.001; Child-Pugh A to C,p < 0.001; Child-Pugh B to C, p < 0.001).

CONCLUSION

Gd-EOB-DTPA-enhanced T1 mapping of the liver parenchyma may present a useful method for determining severity of liver cirrhosis.

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.