Quantitative evaluation of liver function with use of gadoxetate disodium-enhanced MR imaging

Assessment of hepatic transporter function in rats using dynamic gadoxetate-enhanced MRI: a reproducibility study

OBJECTIVE

Previous studies have revealed a substantial between-centre variability in DCE-MRI biomarkers of hepatocellular function in rats. This study aims to identify the main sources of variability by comparing data measured at different centres and field strengths, at different days in the same subjects, and over the course of several months in the same centre.

MATERIALS AND METHODS

13 substudies were conducted across three facilities on two 4.7 T and two 7 T scanners using a 3D spoiled gradient echo acquisition. All substudies included 3-6 male Wistar-Han rats each, either scanned once with vehicle (n = 76) or twice with either vehicle (n = 19) or 10 mg/kg of rifampicin (n = 13) at follow-up. Absolute values, between-centre reproducibility, within-subject repeatability, detection limits, and effect sizes were derived for hepatocellular uptake rate (Ktrans) and biliary excretion rate (kbh). Sources of variability were identified using analysis of variance and stratification by centre, field strength, and time period.

RESULTS

Data showed significant differences between substudies of 31% for Ktrans (p = 0.013) and 43% for kbh (p < 0.001). Within-subject differences were substantially smaller for kbh (8%) but less so for Ktrans (25%). Rifampicin-induced inhibition was safely above the detection limits, with an effect size of 75 ± 3% in Ktrans and 67 ± 8% in kbh. Most of the variability in individual data was accounted for by between-subject (Ktrans = 23.5%; kbh = 42.5%) and between-centre (Ktrans = 44.9%; kbh = 50.9%) variability, substantially more than the between-day variation (Ktrans = 0.1%; kbh = 5.6%). Significant differences in kbh were found between field strengths at the same centre, between centres at the same field strength, and between repeat experiments over 2 months apart in the same centre.

DISCUSSION

Between-centre bias caused by factors such as hardware differences, subject preparations, and operator dependence is the main source of variability in DCE-MRI of liver function in rats, closely followed by biological between-subject differences. Future method development should focus on reducing these sources of error to minimise the sample sizes needed to detect more subtle levels of inhibition.

Gallbladder fossa nodularity in the liver as observed in alcoholic liver disease patients: Analysis based on hepatobiliary phase signal intensity on gadoxetate-enhanced MRI and extracellular volume fraction calculated from routine CT data

The purpose of this study is to further verify the concept utilizing signal intensity on hepatobiliary phase (HBP) of gadoxetate-enhanced MRI and extracellular volume fraction (ECV) calculated from CT data. Between Jan 2013 and September 2018, consecutive ALD patients who had both quadruple phase CT and gadoxetate-enhanced MRI within six months were retrospectively recruited. Those who had any intervention or disease involvement around gallbladder fossa were excluded. All images were reviewed and ECV was measured by two experienced radiologists. GBFN grades, and their HBP signal intensity or ECV relative to the surrounding background liver (BGL) were analyzed. There were 48 patients who met the inclusion criteria. There were GBFN grade 0/1/2/3 in 11/15/18/4 patients, respectively. The signal intensity on HBP relative to BGL were iso/slightly high/high in 30/15/3 patients, respectively, and ECV ratio (ECV of GBFN divided by that of BGL) was 0.88 ± 0.18, indicating there are more functioning hepatocytes and less fibrosis in GBFN than in BGL. The GBFN grades were significantly correlated to relative signal intensity at HBP (Spearman's rank correlation, p < 0.01, rho value 0.53), and ECV ratio (p < 0.01, rho value -0.45). Our results suggest GBFN in ALD would represent liver tissues with preserved liver function with less fibrosis, as compared to BGL, which are considered to support our hypothesis as shown above.

Lobe-Based Hepatic Uptake Index of Gd-EOB-DTPA on Contrast-Enhanced MRI to Quantitatively Discriminate between Compensated and Decompensated Hepatitis B-Related Cirrhosis

Purpose

To use hepatic uptake index (HUI) of liver lobes on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) to discriminate between patients with hepatitis B-related cirrhosis in compensated and decompensated statuses.

Methods

Forty-four consecutive patients with hepatitis B-related cirrhosis who underwent Gd-EOB-DTPA-enhanced MRI were divided into compensated and decompensated statuses based on clinical evaluation. Volume and signal intensity of individual lobes were retrospectively measured to calculate HUI of the right liver lobe (RHUI), medial (MHUI) and lateral (LHUI) left liver lobes, and caudate lobe (CHUI). Spearman's rank correlation analyses were performed to evaluate relationships of lobe-based HUI with Child-Pugh and model for end-stage liver disease (MELD) scoring system scores in compensated and decompensated statuses. The Mann-Whitney U-test was used to compare the lobe-based HUI between compensated and decompensated statuses. The performance of lobe-based HUI in distinguishing cirrhosis was evaluated using receiver operating characteristic (ROC) analysis, and the area under the ROC curve (AUC) was calculated as a measure of accuracy. Delong's method was used for statistical analysis to elucidate which HUI is optimal.

Results

Compensated and decompensated liver cirrhosis were confirmed in 25 (56.82%) and 19 (43.18%) patients, respectively. According to Spearman's rank correlation analysis, RHUI, MHUI, LHUI, and CHUI were all significantly associated with Child-Pugh and MELD scores (all P values <0.05). Receiver operating characteristic analysis demonstrated that among all lobe-based HUI parameters, RHUI could best perform the previous discrimination with a cut-off of 485.73 and obtain an AUC of 0.867. The AUC of RHUI improved and was significantly different from that of MHUI, LHUI, and CHUI (P = 0.03, P = 0.007, and P < 0.001, respectively, Delong's test).

Conclusions

The RHUI could help quantitatively discriminate hepatitis B-related cirrhosis between compensated and decompensated statuses.

Predictive Value of Preoperative ICG-R15 Testing in Post-hepatectomy Liver Failure Following Major Liver Resection: Indian Experience

Surgical resection stands as the preeminent therapeutic approach for both primary hepatocellular carcinoma and metastatic liver malignancies. Its efficacy is contingent upon the attainment of a comprehensive excision while ensuring a sufficient future liver remnant (FLR). However, post-hepatectomy liver failure (PHLF) remains a significant challenge, particularly in patients with preexisting liver disease. The present study aims to investigate the predictive value of the preoperative indocyanine green retention test at 15 min (ICG-R15) in identifying patients at risk of PHLF following major liver resection. This retrospective review focused on patients who underwent the ICG-R15 test before major liver resection between August 2021 and January 2023. All patients underwent standard preoperative evaluation and staging. Patients with primary or metastatic liver cancer planned for major resection and undergoing ICG-R15 were included in the study. Patients with elevated serum bilirubin (> 3 mg/dl) and those not undergoing liver resection or minor liver resection (< 3 segments) were excluded from the study. PHLF was defined by the International Study Group of Liver Surgery (ISGLS) criteria. Follow-up was performed to identify 90-day morbidity. Using univariate and multivariate logistic regression analyses, we confirmed independent risk parameters that predicted postoperative major complications and severe PHLF. The study included 72 patients who underwent preoperative ICG-R15 testing prior to major liver resection. PHLF occurred in 28 patients (38.9%), with 24 patients (33.3%) classified as severity score B and 3 patients (4.16%) had severity score C. Univariate analysis revealed future liver remnant (FLR), ICG-R15, and blood transfusion as predictors of PHLF. Multivariate analysis confirmed FLR (p = 0.019) and ICG-R15 (p = 0.032) as significant predictors. Receiver operating characteristic curve analysis yielded an area under the curve of 0.642 for ICG-R15 in predicting PHLF. An optimal cut-point of 7.5 was determined. Our study highlights the importance of preoperative risk assessment of liver function evaluation using the ICG-R15 test, to predict the risk of PHLF following liver resection. Implementing appropriate interventions, especially in patients with borderline FLR, can improve surgical outcomes and enhance patient safety. Further research and prospective studies are essential to refine risk prediction models and improve rates of PHLF after liver resections.

Comparison of the efficacy of the gadoxetic acid MRI-derived relative enhancement index (REI) and functional liver imaging score (FLIS) in predicting liver function: validation with Albumin-Bilirubin (ALBI) grade

PURPOSE

This study compared the predictive performance of the relative enhancement index (REI) derived from gadoxetic acid (GA)-enhanced MRI with that of the functional liver imaging score (FLIS) in estimating liver function among patients with chronic liver disease (CLD) or liver cirrhosis (LC) by validating them with the albumin-bilirubin (ALBI) grade.

MATERIALS AND METHODS

We retrospectively examined 166 patients (79 women, 87 men; 57.4 years) who were diagnosed with LC or CLD and underwent GA-enhanced MRI between August 2020 and September 2023. The enhancement ratio (ER) is calculated using the formula: ER = [hepatobiliary phase liver signal (SI HBP20)-precontrast liver signal (SI pre)]/SI pre. The REI is calculated using the formula: REI = Liver Volume (LV) × ER. FLIS was assigned from the sum of three HBP image features, each scored between 0 and 2: liver parenchymal enhancement, biliary contrast excretion, and portal vein sign. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff values of ER, REI, and FLIS in differentiating between ALBI grades. The area under the curve (AUC), accuracy, sensitivity, and specificity were calculated for REI and FLIS to distinguish the ALBI grades. Spearman's rank correlation was used to evaluate the ER, REI, and FLIS correlations between the ALBI grades. To evaluate inter-reader reliability for LV, ER, REI, and FLIS, intraclass correlation coefficient (ICC) was used.

RESULTS

ROC curve analysis showed that the optimal cutoff value of REI for predicting ALBI Grade 1 was 899-905 for readers 1 and 2 and 461-477 for ALBI Grade 3, respectively. REI performed best in predicting ALBI Grade 1, achieving an accuracy range of 94%-92.2%, sensitivity of 94.9%-94.1%, and specificity of 91.7%-87.5% for readers 1 and 2, respectively. All parameters showed high accuracy in distinguishing ALBI Grade 3 from other grades. However, REI outperformed the others, showing an accuracy range of 98.8%-97.6%, sensitivity of 94.4%-94.4%, and specificity of 99.3%-98% for readers 1 and 2, respectively. REI showed the best and very strong correlation with ALBI for both readers.

CONCLUSION

REI showed a very strong correlation with the ALBI grades for assessing liver function. It outperformed FLIS in predicting the ALBI grades, indicating its potential as a radiologic tool comparable to or better than FLIS in predicting liver function, especially given its dependence on liver volume.

Assessment of liver function by gadoxetic acid avidity in MRI in a model of rapid liver regeneration in rats

BACKGROUND

This animal study investigates the hypothesis of an immature liver growth following ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) by measuring liver volume and function using gadoxetic acid avidity in magnetic resonance imaging (MRI) in models of ALPPS, major liver resection (LR) and portal vein ligation (PVL).

METHODS

Wistar rats were randomly allocated to ALPPS, LR or PVL. In contrast-enhanced MRI scans with gadoxetic acid (Primovist®), liver volume and function of the right median lobe (=future liver remnant, FLR) and the deportalized lobes (DPL) were assessed until post-operative day (POD) 5. Liver functionFLR/DPL was defined as the inverse value of time from injection of gadoxetic acid to the blood pool-corrected maximum signal intensityFLR/DPL multiplied by the volumeFLR/DPL.

RESULTS

In ALPPS (n = 6), LR (n = 6) and PVL (n = 6), volumeFLR and functionFLR increased proportionally, except on POD 1. Thereafter, functionFLR exceeded volumeFLR increase in LR and ALPPS, but not in PVL. Total liver function was significantly reduced after LR until POD 3, but never undercuts 60% of its pre-operative value following ALPPS and PVL.

DISCUSSION

This study shows for the first time that functional increase is proportional to volume increase in ALPPS using gadoxetic acid avidity in MRI.

Assessing regional hepatic function changes after hypertrophy induction by radioembolisation: comparison of gadoxetic acid-enhanced MRI and 99mTc-mebrofenin hepatobiliary scintigraphy

BACKGROUND

To compare Gd-ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and 99mTc-labelled mebrofenin hepatobiliary scintigraphy (HBS) as imaging-based liver function tests after unilateral radioembolisation (RE) in patients with primary or secondary liver malignancies.

METHODS

Twenty-three patients with primary or secondary liver malignancies who underwent Gd-EOB-DTPA-enhanced MRI within a prospective study (REVoluTion) were evaluated. REVoluTion was a prospective open-label, non-randomised, therapy-optimising study of patients undergoing right-sided or sequential RE for contralateral liver hypertrophy at a single centre in Germany. MRI and hepatobiliary scintigraphy were performed before RE (baseline) and 6 weeks after (follow-up). This exploratory subanalysis compared liver enhancement on hepatobiliary phase MRI normalised to the spleen (liver-to-spleen ratio (LSR)) and the muscle (liver-to-muscle ratio (LMR)) with mebrofenin uptake on HBS for the total liver (TL) and separately for the right (RLL) and left liver lobe (LLL).

RESULTS

Mebrofenin uptake at baseline and follow-up each correlated significantly with LSR and LMR on MRI for TL (≤ 0.013) and RLL (≤ 0.049). Regarding the LLL, mebrofenin uptake correlated significantly with LMR (baseline, p = 0.013; follow-up, p = 0.004), whereas with LSR, a borderline significant correlation was only seen at follow-up (p = 0.051; p = 0.046).

CONCLUSION

LSRs and LMR correlate with mebrofenin uptake in HBS. This study indicates that Gd-EOB-DTPA-enhanced MRI and 99mTc-labelled mebrofenin HBS may equally be used to assess an increase in contralateral liver lobe function after right-sided RE.

RELEVANCE STATEMENT

MRI may be a convenient and reliable method for assessing the future liver remnant facilitating treatment planning and monitoring of patients after RE-induced hypertrophy induction.

KEY POINTS

• Both MRI and HBS can assess liver function after RE. • Liver enhancement on MRI correlates with mebrofenin uptake on HBS. • MRI might be a convenient alternative for estimating future liver remnants after hypertrophy induction.

Evaluation and Prediction of Post-Hepatectomy Liver Failure Using Imaging Techniques: Value of Gadoxetic Acid-Enhanced Magnetic Resonance Imaging

Despite improvements in operative techniques and perioperative care, post-hepatectomy liver failure (PHLF) remains the most serious cause of morbidity and mortality after surgery, and several risk factors have been identified to predict PHLF. Although volumetric assessment using imaging contributes to surgical simulation by estimating the function of future liver remnants in predicting PHLF, liver function is assumed to be homogeneous throughout the liver. The combination of volumetric and functional analyses may be more useful for an accurate evaluation of liver function and prediction of PHLF than only volumetric analysis. Gadoxetic acid is a hepatocyte-specific magnetic resonance (MR) contrast agent that is taken up by hepatocytes via the OATP1 transporter after intravenous administration. Gadoxetic acid-enhanced MR imaging (MRI) offers information regarding both global and regional functions, leading to a more precise evaluation even in cases with heterogeneous liver function. Various indices, including signal intensity-based methods and MR relaxometry, have been proposed for the estimation of liver function and prediction of PHLF using gadoxetic acid-enhanced MRI. Recent developments in MR techniques, including high-resolution hepatobiliary phase images using deep learning image reconstruction and whole-liver T1 map acquisition, have enabled a more detailed and accurate estimation of liver function in gadoxetic acid-enhanced MRI.

Current status of preoperative risk assessment for posthepatectomy liver failure in patients with hepatocellular carcinoma

Liver resection is an effective therapeutic option for patients with hepatocellular carcinoma. However, posthepatectomy liver failure (PHLF) remains a major cause of hepatectomy-related mortality, and the accurate prediction of PHLF based on preoperative assessment of liver functional reserve is a critical issue. The definition of PHLF proposed by the International Study Group for Liver Surgery has gained acceptance as a standard grading criterion. Liver function can be estimated using a variety of parameters, including routine blood biochemical examinations, clinical scoring systems, dynamic liver function tests, liver stiffness and fibrosis markers, and imaging studies. The Child-Pugh score and model for end-stage liver disease scores are conventionally used for estimating liver decompensation, although the alternatively developed albumin-bilirubin score shows superior performance for predicting hepatic dysfunction. Indocyanine green clearance, a dynamic liver function test mostly used in Japan and other Asian countries, serves as a quantitative estimation of liver function reserve and helps determine indications for surgical procedures according to the estimated risk of PHLF. In an attempt to improve predictive accuracy, specific evaluation of liver fibrosis and portal hypertension has gained popularity, including liver stiffness measurements using ultrasonography or magnetic resonance elastography, as well as noninvasive fibrosis markers. Imaging modalities, including Tc-99m-labeled galactosyl serum albumin scintigraphy and gadolinium-enhanced magnetic resonance imaging, are used for preoperative evaluation in combination with liver volume. This review aims to provide an overview of the usefulness of current options for the preoperative assessment of liver function in predicting PHLF.

Four indices on Gd-EOB-DTPA-enhanced MRI can estimate liver functional reserve compared to ICG-R15: A systematic review and meta-analysis

AIMS

To evaluate the value of four indices of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced (Gd-EOB-DTPA) magnetic resonance as a potential imaging marker of liver functional reserve.

METHODS

PubMed/Medline, Embase, Cochrane Library, and Web of Science were searched for studies concerning the relationship between Gd-EOB-DTPA-enhanced MRI and liver functional reserve estimated by ICG-R15, Pooled correlation coefficient (r) and 95% confidence intervals (CIs) were calculated, Meanwhile, Sensitivity and subgroup analyses were performed along with Egger's test for the estimation of publication bias and potential heterogeneity.

RESULTS

14 publications with 1285 patients were included. The pooled r between relative liver enhancement (RLE), reduction rate of T1 relaxation time of the liver (rrT1), liver-to-spleen ratio (LSR), liver-to-muscle ratio (LMR), and ICG-R15 were -0.49 (95% CI, -0.56 to -0.41, p < 0.05), -0.47 (95% CI, -0.57 to -0.36, p < 0.05), -0.45 (95% CI, -0.55 to -0.34, p < 0.05), -0.50 (95% CI, -0.61 to -0.38, p < 0.05). moderate heterogeneity was observed between studies on rrT1, LSR, LMR, and ICG-R15 (p ≤ 0.05), but no significant heterogeneity was observed between RLE and ICG-R15. Further analysis shows that there was a notable heterogeneity between subgroup analysis of LSR and ICG-R15 stratified by years of publication, as well as rrT1 and LMR stratified by total patients and study design, the distribution funnel plots and the results of Egger's test showed no evidence of publication bias.

CONCLUSIONS

RLE, LSR, LMR, and rrT1 all correlated significantly with ICG-R15-estimated hepatic functional reserve. The four indices represent a promising imaging biomarker in the prediction of liver functional reserve.

The value of contrast-enhanced portal vein imaging at the hepatobiliary phase obtained with gadobenate dimeglumine for predicting decompensation and transplant-free survival in chronic liver disease

OBJECTIVES

To investigate the value of contrast-enhanced portal vein imaging at the hepatobiliary phase obtained with gadobenate dimeglumine for predicting clinical outcomes in patients with chronic liver disease (CLD).

METHODS

Three hundred and fourteen CLD patients who underwent gadobenate dimeglumine-enhanced hepatic magnetic resonance imaging were stratified into three groups: nonadvanced CLD (n = 116), compensated advanced CLD (n = 120), and decompensated advanced CLD (n = 78) groups. The liver-to-portal vein contrast ratio (LPC) and liver-spleen contrast ratio (LSC) at the hepatobiliary phase were measured. The value of LPC for predicting hepatic decompensation and transplant-free survival was assessed using Cox regression analysis and Kaplan-Meier analysis.

RESULTS

The diagnostic performance of LPC was significantly better than LSC in evaluating the severity of CLD. During a median follow-up period of 53.0 months, the LPC was a significant predictor for hepatic decompensation (p < 0.001) in patients with compensated advanced CLD. The predictive performance of LPC was higher than that of the model for end-stage liver disease score (p = 0.006). With the optimal cut-off value, patients with LPC ≤ 0.98 had a higher cumulative incidence of hepatic decompensation than patients with LPC > 0.98 (p < 0.001). The LPC was also a significant predictive factor for transplant-free survival in patients with compensated advanced CLD (p = 0.007) and those with decompensated advanced CLD (p = 0.002).

CONCLUSIONS

Contrast-enhanced portal vein imaging at the hepatobiliary phase obtained with gadobenate dimeglumine is a valuable imaging biomarker for predicting hepatic decompensation and transplant-free survival in CLD patients.

KEY POINTS

• The liver-to-portal vein contrast ratio (LPC) significantly outperformed liver-spleen contrast ratio in evaluating the severity of chronic liver disease. • The LPC was a significant predictor for hepatic decompensation in patients with compensated advanced chronic liver disease. • The LPC was a significant predictor for transplant-free survival in patients with compensated and those with decompensated advanced chronic liver disease.

Relative enhancement index can be used to quantify liver function in cirrhotic patients that undergo gadoxetic acid-enhanced MRI

OBJECTIVES

To evaluate MRI with gadoxetic acid to quantify liver function in cirrhotic patients using the relative enhancement index (REI) compared with Child-Pugh score (CPS), MELD score, and indocyanine green plasma disappearance rate (ICG-PDR) and to establish cutoffs for REI to stratify cirrhotic patients into good and poor liver function groups.

METHODS

We prospectively evaluated 60 cirrhotic patients and calculated CPS, MELD score, ICG-PDR, and REI for each patient. Spearman's correlation coefficient was used to assess correlation between REI, CPS, MELD, and ICG-PDR. Good and poor liver function groups were created by k-means clustering algorithm using CPS, MELD, and ICG-PDR. ROC curve analysis was performed and optimal cutoff was identified for group differentiation.

RESULTS

Good correlations were found between REI and other liver function biomarkers: REI and CPS (rho =  - 0.816; p < 0.001); REI and MELD score (rho =  - 0.755; p < 0.001); REI and ICG-PDR (rho = 0.745; p < 0.001)]. REI correlation was stronger for patients with Child-Pugh A (rho = 0.642, p = 0.002) and B (rho = 0.798, p < 0.001) than for those with Child-Pugh C (rho = 0.336, p = 0.148). REI is significantly lower in patients with poor liver function (p < 0.001). ROC curve showed an AUC 0.94 to discriminate patients with poor liver function (REI cutoff < 100; 100% sensitivity; 76% specificity).

CONCLUSIONS

REI is a valuable non-invasive index for liver function quantification that has good correlations with other liver function biomarkers. REI can be easily calculated and can be used to estimate liver function in clinical practice in the routine evaluation of cirrhotic patients that undergo MR imaging with gadoxetic acid contrast.

KEY POINTS

• REI is a valuable non-invasive index for liver function quantification that has good correlations with other liver function biomarkers. • REI can be easily calculated in the routine evaluation of cirrhotic patients that undergo gadoxetic acid-enhanced MRI. • The REI enables stratification of cirrhotic patients into good and poor liver function groups and can be used as additional information, together with morphological and focal liver lesion evaluation.

Evaluation of liver function in patients with liver cirrhosis and chronic liver disease using functional liver imaging scores at different acquisition time points

Purpose: This paper aims to explore whether functional liver imaging score (FLIS) based on Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) images at 5, 10, and 15 min can predict liver function in patients with liver cirrhosis or chronic liver disease and its association with indocyanine green 15-min retention rate (ICG-R₁₅), Child-Pugh (CP) score, albumin-bilirubin (ALBI) score, and model for end-stage liver disease (MELD) score. In addition, it also examines the inter- and intra-observer consistency of FLIS and three FLIS parameters at three different time points. Methods: This study included 110 patients with chronic liver disease (CLD) or liver cirrhosis (LC) (93 men, 17 women; mean ± standard deviation = 56.96 ± 10.16) between July 2019 and May 2022. FLIS was assigned in accordance with the sum of the three hepatobiliary phase characteristics, all of which were scored on the 0-2 ordinal scale, including the biliary excretion, hepatic enhancement and portal vein signal intensity. FLIS was calculated independently by two radiologists using transitional and hepatobiliary phase images at 5, 10, and 15 min after enhancement. The relationship between FLIS and three FLIS quality scores and the degree of liver function were evaluated using Spearman's rank correlation coefficient. The ability of FLIS to predict hepatic function was investigated using receiver operating characteristic (ROC) curves. Results: Intra- and inter-observer intraclass correlation coefficients (ICCs) (ICC = 0.937-0.978, 95% CI = 0.909-0.985) for FLIS at each time point indicated excellent agreement. At each time point, FLIS had a moderate negative association with liver function classification (r = [-0.641]-[-0.428], p < 0.001), and weak to moderate correlation with some other clinical parameters except for creatinine (p > 0.05). FLIS showed moderate discriminatory ability between different liver function levels. The area under the ROC curves (AUCs) of FLIS at 5, 10, and 15 min after enhancement to predict ICG-R₁₅ of 10% or less were 0.838, 0.802, and 0.723, respectively; those for predicting ICG-R₁₅ greater than 20% were 0.793, 0.824, and 0.756, respectively; those for predicting ICG-R₁₅ greater than 40% were 0.728, 0.755, and 0.741, respectively; those for predicting ALBI grade 1 were 0.734, 0.761, and 0.691, respectively; those for predicting CP class A cirrhosis were 0.806, 0.821, and 0.829, respectively; those for predicting MELD score of 10 or less were 0.837, 0.877, and 0.837, respectively. No significant difference was found in the AUC of FLIS at 5, 10 and 15 min (p > 0.05). Conclusion: FLIS presented a moderate negative correlation with the classification system of hepatic function at a delay of 5, 10, and 15 min, and patients with LC or CLD were appropriately stratified based on ICG-R₁₅, ALBI grade, MELD score, and CP classification. In addition, the use of FLIS to evaluate liver function can reduce the observation time of the hepatobiliary period.

Prediction of Decompensation and Death in Advanced Chronic Liver Disease Using Deep Learning Analysis of Gadoxetic Acid-Enhanced MRI

OBJECTIVE

This study aimed to evaluate the usefulness of quantitative indices obtained from deep learning analysis of gadoxetic acid-enhanced hepatobiliary phase (HBP) MRI and their longitudinal changes in predicting decompensation and death in patients with advanced chronic liver disease (ACLD).

MATERIALS AND METHODS

We included patients who underwent baseline and 1-year follow-up MRI from a prospective cohort that underwent gadoxetic acid-enhanced MRI for hepatocellular carcinoma surveillance between November 2011 and August 2012 at a tertiary medical center. Baseline liver condition was categorized as non-ACLD, compensated ACLD, and decompensated ACLD. The liver-to-spleen signal intensity ratio (LS-SIR) and liver-to-spleen volume ratio (LS-VR) were automatically measured on the HBP images using a deep learning algorithm, and their percentage changes at the 1-year follow-up (ΔLS-SIR and ΔLS-VR) were calculated. The associations of the MRI indices with hepatic decompensation and a composite endpoint of liver-related death or transplantation were evaluated using a competing risk analysis with multivariable Fine and Gray regression models, including baseline parameters alone and both baseline and follow-up parameters.

RESULTS

Our study included 280 patients (153 male; mean age ± standard deviation, 57 ± 7.95 years) with non-ACLD, compensated ACLD, and decompensated ACLD in 32, 186, and 62 patients, respectively. Patients were followed for 11-117 months (median, 104 months). In patients with compensated ACLD, baseline LS-SIR (sub-distribution hazard ratio [sHR], 0.81; p = 0.034) and LS-VR (sHR, 0.71; p = 0.01) were independently associated with hepatic decompensation. The ΔLS-VR (sHR, 0.54; p = 0.002) was predictive of hepatic decompensation after adjusting for baseline variables. ΔLS-VR was an independent predictor of liver-related death or transplantation in patients with compensated ACLD (sHR, 0.46; p = 0.026) and decompensated ACLD (sHR, 0.61; p = 0.023).

CONCLUSION

MRI indices automatically derived from the deep learning analysis of gadoxetic acid-enhanced HBP MRI can be used as prognostic markers in patients with ACLD.

Quantitative evaluation of functional liver reserve using the liver-to-spleen ΔR1 ratio based on gadoxetic acid-enhanced MRI: corrected for the effect of gadoxetic acid dose

Background

The liver T1 reduction rate can be used to assess liver function. However, higher doses of gadoxetic acid may shorten the liver T1 value in the hepatobiliary phase and increase the T1 reduction rate in patients with severe liver dysfunction, potentially overestimating liver function.

Purpose

To verify the relationship between the gadoxetic acid dose and the liver T1 reduction rate and ΔR1 of the liver and spleen, and to clarify whether the ΔR1 of hepatocytes, corrected for the effect of gadoxetic acid dose, could be used as an index of functional liver reserve.

Material and Methods

We enrolled 13 patients with normal liver function (NLF); and 18, 8, and 3 patients with Child-Pugh classes A (CPA), B (CPB), and C (CPC) who underwent gadoxetic acid-enhanced magnetic resonance imaging. Phase-sensitive inversion recovery sequence was performed before and at 15 min after injection and T1 maps were calculated. Liver and spleen ΔR1, liver T1 reduction rate, and the liver-to-spleen ΔR1 ratio were calculated.

Results

Only the liver-to-spleen ΔR1 ratio showed no correlation with gadoxetic acid dose in any group. The T1 reduction rate was not significantly different between the CPA and CPB + CPC groups. The liver-to-spleen ΔR1 ratio significantly differed between all groups.

Conclusion

The liver and spleen ΔR1 was dependent on the dose of gadoxetic acid in severe liver dysfunction. The liver-to-spleen ΔR1 ratio improves the delineation of the CPA and CPB + CPC groups.

Performance of native and gadoxetate-enhanced liver and spleen T1 mapping for noninvasive diagnosis of clinically significant portal hypertension: preliminary results

PURPOSE

In this preliminary study, our aim was to assess the utility of quantitative native-T₁ (T₁-pre), iron-corrected T₁ (cT₁) of the liver/spleen and T₁ mapping of the liver obtained during hepatobiliary phase (T₁-HBP) post-gadoxetate disodium, compared to spleen size/volume and APRI (aspartate aminotransferase-to-platelet ratio index) for noninvasive diagnosis of clinically significant portal hypertension [CSPH, defined as hepatic venous pressure gradient (HVPG) ≥ 10 mm Hg].

METHODS

Forty-nine patients (M/F: 27/22, mean age 53y) with chronic liver disease, HVPG measurement and MRI were included. Breath-held T₁ and cT₁ measurements were obtained using an inversion recovery Look-Locker sequence and a T2* corrected modified Look-Locker sequence, respectively. Liver T₁-pre (n = 49), spleen T₁ (obtained pre-contrast, n = 47), liver and spleen cT₁ (both obtained pre-contrast, n = 30), liver T₁-HBP (obtained 20 min post gadoxetate disodium injection, n = 36) and liver T₁ uptake (ΔT₁, n = 36) were measured. Spleen size/volume and APRI were also obtained. Spearman correlation coefficients were used to assess the correlation between each of liver/spleen T₁/cT₁ parameters, spleen size/volume and APRI with HVPG. ROC analysis was performed to determine the performance of measured parameters for diagnosis of CSPH.

RESULTS

There were 12/49 (24%) patients with CSPH. Liver T₁-pre (r = 0.287, p = 0.045), liver T₁-HBP (r = 0.543, p = 0.001), liver ΔT₁ (r =  - 0.437, p = 0.008), spleen T₁ (r = 0.311, p = 0.033) and APRI (r = 0.394, p = 0.005) were all significantly correlated with HVPG, while liver cT₁, spleen cT₁ and spleen size/volume were not. The highest AUCs for the diagnosis of CSPH were achieved with liver T₁-HBP, liver ΔT₁ and spleen T₁: 0.881 (95%CI 0.76-1.0, p = 0.001), 0.852 (0.72-0.98, p = 0.002) and 0.781 (0.60-0.95, p = 0.004), respectively.

CONCLUSION

Our preliminary results demonstrate the potential of liver T₁ mapping obtained during HBP post gadoxetate disodium for the diagnosis of CSPH. These results require further validation.

Determination of hepatic extraction fraction with gadoxetate low‐temporal resolution DCE‐MRI ‐based deconvolution analysis: validation with ALBI score and Child‐Pugh class

INTRODUCTION

In this study, we aimed to investigate the feasibility of gadoxetate low-temporal resolution (LTR) DCE-MRI for voxel-based hepatic extraction fraction (HEF) quantification for liver sparing radiotherapy using a deconvolution analysis (DA) method.

METHODS

The accuracy and consistency of the deconvolution implementation in estimating liver function was first assessed using simulation data. Then, the method was applied to DCE-MRI data collected retrospectively from 64 patients (25 normal liver function and 39 cirrhotic patients) to generate HEF maps. The normal liver function patient data were used to measure the variability of liver function quantification. Next, a correlation between HEF and ALBI score (a new model for assessing the severity of liver dysfunction) was assessed using Pearson's correlation. Differences in HEF between Child-Pugh score classifications were assessed for significance using the Kruskal-Wallis test for all patient groups and Mann-Whitney U-test for inter-groups. A statistical significance was considered at a P-value <0.05 in all tests.

RESULTS

The results showed that the implemented method accurately reproduced simulated liver function; root-mean-square error between estimated and simulated liver response functions was 0.003, and the coefficient-of-variance of HEF was <20%. HEF correlation with ALBI score was r = -0.517, P < 0.0001, and HEF was significantly decreased in the cirrhotic patients compared to normal patients (P < 0.0001). Also, HEF in Child-Pugh B/C was significantly lower than in Child-Pugh A (P = 0.024).

CONCLUSION

The study demonstrated the feasibility of gadoxetate LTR-DCE MRI for voxel-based liver function quantification using DA. HEF could distinguish between different grades of liver function impairment and could potentially be used for functional guidance in radiotherapy.

MELIF, a Fully Automated Liver Function Score Calculated from Gd-EOB-DTPA-Enhanced MR Images: Diagnostic Performance vs. the MELD Score

In the management of patients with chronic liver disease, the assessment of liver function is essential for treatment planning. Gd-EOB-DTPA-enhanced MRI allows for both the acquisition of anatomical information and regional liver function quantification. The objective of this study was to demonstrate and evaluate the diagnostic performance of two fully automatically generated imaging-based liver function scores that take the whole liver into account. T1 images from the native and hepatobiliary phases and the corresponding T1 maps from 195 patients were analyzed. A novel artificial-intelligence-based software prototype performed image segmentation and registration, calculated the reduction rate of the T1 relaxation time for the whole liver (rrT1_liver) and used it to calculate a personalized liver function score, then generated a unified score—the MELIF score—by combining the liver function score with a patient-specific factor that included weight, height and liver volume. Both scores correlated strongly with the MELD score, which is used as a reference for global liver function. However, MELIF showed a stronger correlation than the rrT1_liver score. This study demonstrated that the fully automated determination of total liver function, regionally resolved, using MR liver imaging is feasible, providing the opportunity to use the MELIF score as a diagnostic marker in future prospective studies.

Determining the efficacy of functional liver imaging score (FLIS) obtained from gadoxetic acid-enhanced MRI in patients with chronic liver disease and liver cirrhosis: the relationship between Albumin-Bilirubin (ALBI) grade and FLIS

PURPOSE

(1) To evaluate the efficacy of functional liver imaging score (FLIS) in predicting liver function on gadoxetic acid-enhanced MRI in patients with chronic liver disease (CLD) or liver cirrhosis (LC) and its relationship with ALBI grade. (2) To assess the intra-reader reliability and interreader agreement of readers with different levels of experience in abdominal imaging of FLIS.

METHODS

We retrospectively included 131 patients (70 men, 61 women; mean ± SD, 53.7 ± 14.6 years) with CLD and LC who underwent GA-enhanced MRI between November 2019 and March 2022. FLIS was assigned as a result of the sum of three hepatobiliary phase (HBP) images features, each scored 0-2: liver parenchymal enhancement, biliary contrast excretion, and portal vein sign. FLIS was calculated using HPB images independently by three radiologists with different experience. In addition, 50 randomly selected patients were reviewed a second time by a reader to assess intra-reader reliability. Patients were divided into the following three groups according to the albumin-bilirubin (ALBI) grade: ALBI grade 1, 2, and 3. We evaluated the correlation between ALBI grade and both FLIS and its parameters using Spearman's rank correlation for each reader. Receiver operating characteristic (ROC) curve analysis was performed to show the optimal cut-off value of FLIS to distinguish between ALBI grades. Intra-reader reliability and inter-reader agreement were evaluated by intraclass correlation coefficient (ICC).

RESULTS

FLIS and three FLIS parameters showed very strong correlation with ALBI grade for each readers (r =  - 0.843 to 0.976, - 0.831 to 0.962, and - 0.819 to 0.902, respectively). ROC curve analysis showed that FLIS ≥ 5 was the optimal cutoff for prediction of ALBI grade 1 for each readers (sensitivity, 83.7% to 95.4%; specificity, 82.6% to 87%; accuracy, 88.6% to 93.6% and area under the curve (AUC), 0.882 to 0.917), and FLIS ≤ 3 was the optimal cutoff for distinguish ALBI grade 3 from other grades for each readers (sensitivity, 100%; specificity, 95.2% to 96%; accuracy, 95.4% to 96.2% and AUC, 0.974 to 0.994). Intra-reader reliability (ICC = 0.95; 95% CI 0.93-0.96) and inter-reader agreement (ICC = 0.85 to 0.90; 95% CI 0.82-0.97) for FLIS were excellent.

CONCLUSION

FLIS showed a very correlation with hepatic function level and can stratify the ALBI grades. This feature has demonstrated the potential of FLIS to be excellent radiological tools for predicting of liver function of CLD and LC patients in clinical practice. Also, the excellent agreement of FLIS among readers with different levels of experience indicates that it can be used with high accuracy and reproducibility regardless of experience.

Gadoxetic acid-enhanced magnetic resonance imaging predicts hyperbilirubinemia induced by glecaprevir during hepatitis C virus treatment

Glecaprevir is a substrate for organic anion-transporting polypeptide (OATP) 1B1/1B3, which transports bilirubin. Hyperbilirubinemia is an adverse event during anti-hepatitis C virus treatment with glecaprevir and pibrentasvir. Gadoxetic acid is also transported by OATP1B1/1B3, and we aimed to evaluate whether gadoxetic acid-enhanced magnetic resonance (MR) imaging was associated with glecaprevir trough concentrations (C_trough). We further determined whether this was predictive of hyperbilirubinemia development in a cohort of 33 patients. The contrast enhancement index (CEI), a measure of hepatic enhancement effect on the hepatobiliary image, was assessed. Glecaprevir C_trough was determined 7 days after administration. Five of the 33 patients (15%) developed Common Terminology Criteria for Adverse Events grade ≥ 2 hyperbilirubinemia. We found a negative relationship between CEI and C_trough (r = − 0.726, p < 0.001). The partial correlation coefficient between CEI and C_trough was − 0.654 (p < 0.001), while excluding the effects of albumin, FIB-4 index, and indirect bilirubin at baseline. The C_trough was significantly higher in patients with hyperbilirubinemia than in those without (p = 0.008). In multivariate analysis, CEI ≤ 1.71 was an independent factor influencing the development of hyperbilirubinemia (p = 0.046). Our findings indicate that gadoxetic acid MR imaging can help predict glecaprevir concentration and development of hyperbilirubinemia.

Gadoxetate-Enhanced MRI as a Diagnostic Tool in the Management of Hepatocellular Carcinoma: Report from a 2020 Asia-Pacific Multidisciplinary Expert Meeting

Gadoxetate magnetic resonance imaging (MRI) is widely used in clinical practice for liver imaging. For optimal use, we must understand both its advantages and limitations. This article is the outcome of an online advisory board meeting and subsequent discussions by a multidisciplinary group of experts on liver diseases across the Asia-Pacific region, first held on September 28, 2020. Here, we review the technical considerations for the use of gadoxetate, its current role in the management of patients with hepatocellular carcinoma (HCC), and its relevance in consensus guidelines for HCC imaging diagnosis. In the latter part of this review, we examine recent evidence evaluating the impact of gadoxetate on clinical outcomes on a continuum from diagnosis to treatment decision-making and follow-up. In conclusion, we outline the potential future roles of gadoxetate MRI based on an evolving understanding of the clinical utility of this contrast agent in the management of patients at risk of, or with, HCC.

Gd-BOPTA-enhanced hepatobiliary phase MR imaging can predict the prognosis of patients with acute-on-chronic liver failure

OBJECTIVES

To determine the value of gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance imaging (MRI) from the hepatobiliary phase for predicting poor outcome in acute-on-chronic liver failure (ACLF) patients.

METHODS

In this single-center retrospective study, 74 patients diagnosed as ACLF who underwent Gd-BOPTA-enhanced hepatobiliary magnetic resonance imaging were collected. The quantitative liver-spleen contrast ratio (Q-LSC) and the relative enhancement ratio of the biliary system (REB) at the hepatobiliary phase were measured. Cox proportional hazards regression models were used to evaluate prognostic factors. The capacity of the Q-LSC and REB to predict the 90-day outcome was evaluated via receiver operating characteristic (ROC) curve.

RESULTS

During the follow-up period, twenty-eight of 74 ACLF patients (38%) had a poor outcome. The Q-LSC and REB were significant predictive factors (hazard ratio [HR] = 0.03 [0.002-0.54], p < 0.05; HR = 0.07 [0.01-0.88], p < 0.05) for prognosis in patients with ACLF. Moreover, the areas under the ROC curves of Q-LSC and REB for predicting poor outcome in patients with ACLF were 0.81 and 0.80, respectively. The most appropriate cutoff values for the Q-LSC and REB were 1.09 and 0.57, respectively. The ACLF patients with the Q-LSC ≤ 1.09 or REB ≤ 0.57 had a low cumulative survival.

CONCLUSIONS

Gd-BOPTA-enhanced hepatobiliary phase MR imaging can predict poor outcome in patients with acute-on-chronic liver failure.

KEY POINTS

• The quantitative liver-spleen contrast ratio at the hepatobiliary phase was a significant predictive prognostic factor in patients with acute-on-chronic liver failure. • The relative enhancement ratio of the biliary system at the hepatobiliary phase was a significant prognostic factor in patients with acute-on-chronic liver failure. • Gadobenate dimeglumine contrast-enhanced MR imaging from the hepatobiliary phase can predict poor outcome in patients with acute-on-chronic liver failure.

Assessment of Liver Function With MRI: Where Do We Stand?

Liver disease and hepatocellular carcinoma (HCC) have become a global health burden. For this reason, the determination of liver function plays a central role in the monitoring of patients with chronic liver disease or HCC. Furthermore, assessment of liver function is important, e.g., before surgery to prevent liver failure after hepatectomy or to monitor the course of treatment. Liver function and disease severity are usually assessed clinically based on clinical symptoms, biopsy, and blood parameters. These are rather static tests that reflect the current state of the liver without considering changes in liver function. With the development of liver-specific contrast agents for MRI, noninvasive dynamic determination of liver function based on signal intensity or using T1 relaxometry has become possible. The advantage of this imaging modality is that it provides additional information about the vascular structure, anatomy, and heterogeneous distribution of liver function. In this review, we summarized and discussed the results published in recent years on this technique. Indeed, recent data show that the T1 reduction rate seems to be the most appropriate value for determining liver function by MRI. Furthermore, attention has been paid to the development of automated tools for image analysis in order to uncover the steps necessary to obtain a complete process flow from image segmentation to image registration to image analysis. In conclusion, the published data show that liver function values obtained from contrast-enhanced MRI images correlate significantly with the global liver function parameters, making it possible to obtain both functional and anatomic information with a single modality.

Quantitative evaluation of liver function with gadoxetic acid enhanced MRI: Comparison among signal intensity-, T1-relaxometry-, and dynamic-hepatocyte-specific-contrast-enhanced MRI- derived parameters

AIMS

Three types of gadoxetic acid enhanced MRI parameters have been proposed to quantify liver function. However, until now there is no consensus on which one that has the greatest potential for use in clinical practice. This study was conducted to compare the efficacy of three types of gadoxetic acid enhanced MR parameters for quantitative assessment of liver function.

METHODS

Imaging data of 10 patients with chronic liver disease and 20 healthy volunteers were analyzed. Parameters based on signal intensity(SI), T1 changes or dynamic-hepatocyte-specific-contrast-enhancement MR were calculated. Their mutual correlations, discriminatory capacity between cirrhotic and healthy liver and correlations with Child-Pugh score and Model for end-stage liver-disease (MELD) were estimated.

RESULTS

The strongest correlations were observed between relative enhancement of the liver and T1 time at 20 min after contrast agent injection, and between liver-spleen contrast ratio at 20 min after contrast agent injection and hepatic uptake rate (|r|> 0.90, p < .05, both). All parameters but input-relative blood flow (p = 0.17) were significantly different between patient and control group (p < .05), with AUROCs of liver-to-muscle ratio (LMR), increase of LMR and hepatic extraction fraction greater than 0.90 (p < .05). Liver-to-spleen ratio, LMR and hepatic uptake index presented a strong correlation with Child-Pugh score and MELD (|r|> 0.8, p < .05).

CONCLUSION

Simple SI-based parameters were as good as more complex parameters in evaluating liver function at gadoxetic acid enhanced MR. In clinical routine LMR seems to be the easiest-to-use parameter for quantitative evaluation of liver function.

Assessing the progression of segmental fibrosis in chronic liver disease using extracellular volume fractions

PURPOSE

To assess the segmental difference of liver fibrosis during the progression of chronic liver disease (CLD) using hepatic extracellular volume fractions (fECVs) obtained by dual-energy CT.

METHODS

A total of 218 patients (92 men and 126 women; mean age, 67.8 ± 11.7 years) with CLD and 85 patients (44 men and 41 women; mean age, 62.8 ± 13.7 years) without CLD as a control underwent dual-energy computed tomography (CT) of the liver (5-min equilibrium phase images). The iodine densities of the lateral, medial, anterior, and posterior segments and the aorta were measured, and fECVs were calculated. Comparisons of the fECV of each segment and for each albumin-bilirubin (ALBI) grade were then statistically analyzed.

RESULTS

In the control group and ALBI grades 1 and 3, no significant difference in fECV was found between each segment, whereas in ALBI grade 2, the fECVs were significantly larger in the medial and anterior than in the other segments (p < 0.001). The fECVs of the lateral and posterior segments significantly increased with higher ALBI grade (p < 0.001). The fECVs of the medial and anterior segments were significantly increased with higher ALBI grade, up to grade 2 (p < 0.001), but no significant difference was found between ALBI grades 2 and 3.

CONCLUSION

During the progression of CLD, fibrosis antecedently progressed in the medial and anterior segments, followed by the other liver segments.

Predictive value of gadoxetic acid-enhanced MRI for posthepatectomy liver failure: a systematic review

Objectives

Effective and non-invasive biomarkers to predict and avoid posthepatectomy liver failure (PHLF) are urgently needed. This systematic review aims to evaluate the efficacy of gadoxetic acid–enhanced MRI-derived parameters as an imaging biomarker in preoperative prediction of PHLF.

Methods

A systematic literature search was performed in the databases of PubMed/Medline, Web of Science, Embase, and Cochrane Library up to 11 December 2020. Studies evaluating the incidence of PHLF on patients who underwent hepatectomy with preoperative liver function assessment using gadoxetic acid–enhanced MRI were included. Data was extracted using pre-designed tables. The Quality In Prognostic Studies (QUIPS) tool was adopted to evaluate the risk of bias.

Results

A total of 15 studies were identified for qualitative synthesis and most studies were marked as low to moderate risk of bias in each domain of QUIPS. The most commonly used parameter was relative liver enhancement or its related parameters. The reported incidence of PHLF ranged from 3.9 to 40%. The predictive sensitivity and specificity of gadoxetic acid–enhanced MRI parameters varied from 75 to 100% and from 54 to 93% in ten reported studies. A majority of the studies revealed that the gadoxetic acid–enhanced MRI parameter was a predictor for PHLF.

Conclusions

Gadoxetic acid–enhanced MRI showed a high predictive capacity for PHLF and represents a promising imaging biomarker in prediction of PHLF. Multicenter, prospective trials with large sample size and reliable, unified liver function parameters are required to validate the efficacy of individual liver function parameters.

Key Points

• There is an obvious heterogeneity of the published studies, not only in variance of MRI liver function parameters but also in indication and extent of the liver resection.

• Signal intensity (SI)–based parameters derived from gadoxetic acid–enhanced MRI are the commonly used method for PHLF prediction.

• Gadoxetic acid–enhanced MRI-derived parameters showed high predictive efficacy for PHLF and can potentially serve as a predictor for the incidence of PHLF.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08297-8.

Importance of extracellular volume fraction of the spleen as a predictive biomarker for high-risk esophago-gastric varices in patients with chronic liver diseases: A preliminary report

PURPOSE

To clarify clinico-radiological factors for high-risk esophago-gastric varices (EGV), including extracellular volume fraction (ECV) of the liver, pancreas, and the spleen.

METHODS

Between 2014 and 2018, 70 chronic liver disease patients who underwent 4-phase CT of the upper abdomen and either of upper gastrointestinal tract endoscopy, or actual treatment for bleeding EGV, within three months after CT, were retrospectively included. Patients were subdivided into high-risk EGV group (HRG), who had high-risk endoscopic findings or actual hemostatic treatments, and non-high-risk EGV group (NHRG). ECV of the liver, pancreas, and the spleen was measured on the ECV map generated from routine diagnostic CT data, and additional clinico-radiological factors including direct visualization of EGV on portal venous phase CT, were correlated to HRG, using both univariable and multivariable analyses.

RESULTS

There were 8 and 62 patients in HRG, and NHRG, respectively. None had symptoms related to EGV at the time of CT examinations. Univariable analysis revealed splenic volume, liver and splenic ECVs, and EGV visualization on portal venous phase CT, as significant factors. Multivariable analysis suggested that EGV visualization, splenic ECV, and splenic volume were independently significant factors. Using these three factors, sensitivity/specificity/positive predictive value/negative predictive value/accuracy = 100/85/40/100/87% were obtained with partition model analysis.

CONCLUSIONS

High-risk EGV can be predicted with acceptable accuracy using routine diagnostic CT data including splenic ECV.

Diagnosis of Hepatocellular Carcinoma Using Gd-EOB-DTPA MR Imaging

Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA; Gadoxetic acid; Gadoxetate disodium) is a hepatocyte-specific MR contrast agent. It acts as an extracellular contrast agent in the early phase after intravenous injection, and then is taken up by hepatocytes later. Using this contrast agent, we can evaluate the hemodynamics of the liver and liver tumors, and can therefore improve the detection and characterization of hepatocellular carcinoma (HCC). Gd-EOB-DTPA helps in the more accurate detection of hypervascular HCC than by other agents. In addition, Gd-EOB-DTPA can detect hypovascular HCC, which is an early stage of the multi-stage carcinogenesis, with a low signal in the hepatobiliary phase. In addition to tumor detection and characterization, Gd-EOB-DTPA contrast-enhanced MR imaging can be applied for liver function evaluation and prognoses evaluation. Thus, Gd-EOB-DTPA plays an important role in the diagnosis of HCC. However, we have to employ optimal imaging techniques to improve the diagnostic ability. In this review, we aimed to discuss the characteristics of the contrast media, optimal imaging techniques, diagnosis, and applications.

Hepatocellular uptake index obtained with gadoxetate disodium-enhanced magnetic resonance imaging in the assessment future liver remnant function after major hepatectomy for biliary malignancy

Background

Functional assessment of the future liver remnant (FLR) after major hepatectomy is essential but often difficult in patients with biliary malignancy, owing to obstructive jaundice and portal vein embolization. This study evaluated whether a novel index using gadoxetate disodium-enhanced MRI (EOB-MRI) could predict posthepatectomy liver failure (PHLF) after major hepatectomy for biliary malignancy.

Methods

The remnant hepatocellular uptake index (rHUI) was calculated in patients undergoing EOB-MRI before major hepatectomy for biliary malignancy. Receiver operating characteristic (ROC) curve analyses were used to evaluate the accuracy of rHUI for predicting PHLF grade B or C, according to International Study Group of Liver Surgery criteria. Multivariable logistic regression analyses comprised stepwise selection of parameters, including rHUI and other conventional indices.

Results

This study included 67 patients. The rHUI accurately predicted PHLF (area under the curve (AUC) 0.896). A cut-off value for rHUI of less than 0.410 predicted all patients who developed grade B or C PHLF. In multivariable analysis, only rHUI was an independent risk factor for grade B or C PHLF (odds ratio 2.0 × 10³, 95 per cent c.i. 19.6 to 3.8 × 10⁷; P < 0.001). In patients who underwent preoperative portal vein embolization, rHUI accurately predicted PHLF (AUC 0.885), whereas other conventional indices, such as the plasma disappearance rate of indocyanine green of the FLR and FLR volume, did not.

Conclusion

The rHUI is potentially a useful predictor of PHLF after major hepatectomy for biliary malignancy.

CT-Based Prediction of Liver Function and Post-PVE Hypertrophy Using an Artificial Neural Network

Background: This study aimed to evaluate whether hypertrophy after portal vein embolization (PVE) and maximum liver function capacity (LiMAx) are predictable by an artificial neural network (ANN) model based on computed tomography (CT) texture features. Methods: We report a retrospective analysis on 118 patients undergoing preoperative assessment by CT before and after PVE for subsequent extended liver resection due to a malignant tumor at RWTH Aachen University Hospital. The LiMAx test was carried out in a subgroup of 55 patients prior to PVE. Associations between CT texture features and hypertrophy as well as liver function were assessed by a multilayer perceptron ANN model. Results: Liver volumetry showed a median hypertrophy degree of 33.9% (16.5–60.4%) after PVE. Non-response, defined as a hypertrophy grade lower than 25%, was found in 36.5% (43/118) of the cases. The ANN prediction of the hypertrophy response showed a sensitivity of 95.8%, specificity of 44.4% and overall prediction accuracy of 74.6% (p < 0.001). The observed median LiMAx was 327 (248–433) μg/kg/h and was strongly correlated with the predicted LiMAx (R² = 0.89). Conclusion: Our study shows that an ANN model based on CT texture features is able to predict the maximum liver function capacity and may be useful to assess potential hypertrophy after performing PVE.

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.

[Magnetic resonance imaging in liver function analysis. Modern objective reality]

Chronic liver disease is a serious worldwide problem because its progression is accompanied by liver fibrosis and cirrhosis at the terminal stages. Primary diagnosis and dynamic assessment of liver fibrosis are essential to determine the prognosis of disease and optimal treatment strategy. Long-term world experience in the use of gadoxetic acid (primovist, eovist) for diagnosis of liver diseases confirms its hepatotropic properties. Thus, magnetic resonance imaging (MRI) in hepatobiliary phase of contrast enhancement is valuable for differential diagnosis of focal liver lesions and assessment of liver structure and fibrotic changes. This review is devoted to the most common methods of contrast-enhanced MRI for assessment of liver function and correlation between severity of diffuse structural liver changes and gadoxetic acid accumulation in liver parenchyma. There is no a single method for MRI-based analysis of liver function that is confirmed by active researches in this direction. It was found that liver biopsy can by unnecessary in some cases if contrast-enhanced MRI with gadoxetic acid is available. The advantage of gadoxetic acid is also elimination properties. Indeed, biliary excretion ensures T1-weighted MR-cholangiography for additional assessment of patency, function and anatomy of the bile ducts. However, there are still several questions in this area that necessitates further research.

Quantitative assessment of liver function with hepatocyte fraction: Comparison with T1 relaxation-based indices

PURPOSE

This study aimed to assess the use of hepatocyte fraction in gadoxetic acid-enhanced magnetic resonance imaging (MRI) for quantitatively evaluating the liver function in comparison with T1 relaxation-based indices.

METHODS

This retrospective study included 79 patients with chronic liver disease, who were divided into 2 groups based on the results of the indocyanine green retention test (ICG). All patients underwent a gadoxetic acid-enhanced MRI of the liver. Pre- and post-contrast Look-Locker sequences were used 20 min after gadoxetic acid administration to acquire T1 mapping. Two readers independently identified and measured the MRI parameters [five T1 relaxation-based indices (T1pre, T1post, rrT1, R1post/R1pre and ΔR1) and two hepatocyte fraction indices (HeF and K_Hep)]. An Independent-samples t test was used to compare each parameter for the two groups. Pearson correlation analysis was used to analyze the correction in each parameter and 15-minute ICG retention rate (ICG-R15). Receiver operating characteristic analyses were performed to differentiate the diagnostic performance of each parameter in ICG-R15 ≤ 20 % and ICG-R15 > 20 % groups.

RESULTS

T1pre and T1post were significantly lower in the ICG-R15 ≤ 20 % group than in the ICG-R15 > 20 % group (P < 0.05). rrT1, R1post/R1pre, ΔR1, HeF, and K_Hep were significantly higher in the ICG-R15 ≤ 20 % group than in the ICG-R15 > 20 % group (P < 0.05). The correction coefficients between T1pre, T1post, rrT1, R1post/R1pre, ΔR1, HeF, K_Hep, and ICG-R15 were 0.343, 0.783, -0.833, -0.781, -0.803, -0.819, and -0.832, respectively. The area under the curves (AUCs) of T1pre, T1post, rrT1, R1post/R1pre, ΔR1, HeF, and K_Hep in assessing the ICG-R15＞20 % groups were 0.761, 0.945, 0.912, 0.912, 0.948, 0.945, and 0.950, respectively. K_Hep had the highest AUC, sensitivity, and specificity.

CONCLUSION

Hepatocyte fraction based on gadoxetic acid-enhanced T1-mapping MRI is an efficient diagnostic tool for the quantitative evaluation of liver function.

Hepatocellular carcinoma with indocyanine green excretory defect: a case report and review of the literature

Constitutional indocyanine green (ICG) excretory defect is rare. However, ICG excretory defect concomitant with hepatocellular carcinoma (HCC) is extremely rare, and only six reports of hepatectomy in patients with constitutional ICG excretory defect have been published in the English language literature through 2020. In this study, we report a case of combined HCC and ICG excretory defect and discuss its clinicopathological features and outcomes. The case featured a 68-year-old man who was admitted to the hospital with a diagnosis of resectable HCC. The preoperative ICG retention rate at 15 minutes was 82.9%. Despite this finding, the Child–Pugh assessment and hepatobiliary-specific magnetic resonance imaging (MRI) did not reveal any abnormal findings. Therefore, we diagnosed the patient with constitutional ICG excretory defect and performed partial hepatectomy. For patients requiring hepatectomy, the indications and procedure for surgery should be considered. These should be based on liver function tests such as gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced MRI.

Validation of functional liver imaging scores (FLIS) derived from gadoxetic acid-enhanced MRI in patients with chronic liver disease and liver cirrhosis: the relationship between Child-Pugh score and FLIS

OBJECTIVES

To validate the functional liver imaging score (FLIS) for prediction of hepatic function in gadoxetic acid-enhanced MRI.

METHODS

We retrospectively identified 134 patients (88 men, 46 women; mean age, 58.8 years) between January 2015 and December 2018 with the following inclusion criteria: patients diagnosed with liver cirrhosis or chronic liver disease (CLD) who underwent gadoxetic acid-enhanced MRI. Three parameters on hepatobiliary phase images were evaluated for FLIS: liver parenchymal enhancement, biliary excretion, and signal intensity of the portal vein. Patients were classified as CLD (n = 11), Child-Pugh (CP) class A (n = 87), CP B (n = 22), or CP C (n = 14). We assessed the correlation between CP score and both FLIS and its components using Spearman rank correlation. Receiver operating characteristic (ROC) curve analysis was performed to demonstrate the cutoff value of FLIS for differentiating between CP classes. The associations between patient characteristics, serum markers, FLIS, and hepatic decompensation were evaluated with Cox proportional hazard models.

RESULTS

FLIS and three FLIS parameters showed strong to very strong correlation with CP score (r = -0.60 to 0.82). ROC curve analysis showed that FLIS ≥ 5 was the optimal cutoff for prediction of CP class A or CLD (sensitivity, 83.7%; specificity, 94.4%; area under the curve [AUC], 0.93). FLIS < 5 was independently associated with the development of first hepatic decompensation in patients with CP A (HR, 50.0; 95% confidence interval, 6.2, 400.4).

CONCLUSION

FLIS showed a strong correlation with hepatic function and can stratify the CP class. In addition, FLIS can help prediction for the development of first decompensation.

KEY POINTS

• Functional liver imaging scores (FLIS) and its three parameters, derived from hepatobiliary phase image, have strong to very strong correlations with Child-Pugh (CP) scores. • FLIS can stratify patients with chronic liver disease or liver cirrhosis according to CP classification. • Low FLIS is an independent predictor for first hepatic decompensation in patients with CP class A.

Quantitative analysis of gadoxetic acid-enhanced MRI for the differential diagnosis of focal liver lesions: Comparison between estimated intralesional gadoxetic acid retention by T1 mapping and conventional processing methods

PURPOSE

To compare the estimated quantity of intratumor gadoxetic acid retention using T1 mapping of gadoxetic acid-enhanced magnetic resonance imaging (MRI) versus conventional processing methods for the differential diagnosis of focal liver lesions.

METHODS

Seventy patients with hepatic lesions (colorectal metastasis (CRM) [n = 28], hepatocellular carcinoma (HCC) [n = 20], hemangioma [n = 12], and intrahepatic cholangiocarcinoma (ICC) [n = 10]) underwent gadoxetic acid-enhanced MRI, including pre- and post-contrast T1-weighted imaging and T1 mapping. Quantitative analyses included the lesion-to-liver signal intensity ratio (SIR) on hepatobiliary phase images, the pre- and post-contrast lesion T1 value difference (ΔT1 [ms]), and the lesion retention index (LRI [%]), which was the estimated intralesional gadoxetic acid retention calculated on pre- and post-contrast T1 maps using a two-compartment pharmacokinetic model. Results were compared between the four subcategories of focal liver lesions using the Kruskal-Wallis test, followed by the post-hoc Dunn's test and receiver operating characteristic (ROC) analysis to distinguish between pairs of the four lesion subcategories.

RESULTS

This study identified significant differences in the LRI of the four lesion subcategories (p <  0.01), without significant differences in ΔT1 or SIR. Post-hoc analysis demonstrated significant differences in CRM vs. hemangioma (p <  0.01), hemangioma vs. ICC (p <  0.01), and HCC vs. ICC (p =  0.047) for the LRI.

CONCLUSIONS

The quantity of intratumor gadoxetic acid retention estimated using pre- and post- contrast T1 mapping could distinguish focal liver lesions, unlike conventional processing methods, and captured unique lesion characteristics.

Ex vivo gadoxetate relaxivities in rat liver tissue and blood at five magnetic field strengths from 1.41 to 7 T

Quantitative mapping of gadoxetate uptake and excretion rates in liver cells has shown potential to significantly improve the management of chronic liver disease and liver cancer. Unfortunately, technical and clinical validation of the technique is currently hampered by the lack of data on gadoxetate relaxivity. The aim of this study was to fill this gap by measuring gadoxetate relaxivity in liver tissue, which approximates hepatocytes, in blood, urine and bile at magnetic field strengths of 1.41, 1.5, 3, 4.7 and 7 T. Measurements were performed ex vivo in 44 female Mrp2 knockout rats and 30 female wild-type rats who had received an intravenous bolus of either 10, 25 or 40 μmol/kg gadoxetate. T1 was measured at 37 ± 3°C on NMR instruments (1.41 and 3 T), small-animal MRI (4.7 and 7 T) and clinical MRI (1.5 and 3 T). Gadolinium concentration was measured with optical emission spectrometry or mass spectrometry. The impact on measurements of gadoxetate rate constants was determined by generalizing pharmacokinetic models to tissues with different relaxivities. Relaxivity values (L mmol-1 s-1 ) showed the expected dependency on tissue/biofluid type and field strength, ranging from 15.0 ± 0.9 (1.41) to 6.0 ± 0.3 (7) T in liver tissue, from 7.5 ± 0.2 (1.41) to 6.2 ± 0.3 (7) T in blood, from 5.6 ± 0.1 (1.41) to 4.5 ± 0.1 (7) T in urine and from 5.6 ± 0.4 (1.41) to 4.3 ± 0.6 (7) T in bile. Failing to correct for the relaxivity difference between liver tissue and blood overestimates intracellular uptake rates by a factor of 2.0 at 1.41 T, 1.8 at 1.5 T, 1.5 at 3 T and 1.2 at 4.7 T. The relaxivity values derived in this study can be used retrospectively and prospectively to remove a well-known bias in gadoxetate rate constants. This will promote the clinical translation of MR-based liver function assessment by enabling direct validation against reference methods and a more effective translation between in vitro findings, animal models and patient studies.

Advances in functional and molecular MRI technologies in chronic liver diseases

MRI has emerged as the most comprehensive non-invasive diagnostic tool for liver diseases. In recent years, the value of MRI in hepatology has been significantly enhanced by a wide range of contrast agents, both clinically available and under development, that add functional information to anatomically detailed morphological images, or increase the distinction between normal and pathological tissues by targeting molecular and cellular events. Several classes of contrast agents are available for contrast-enhanced hepatic MRI, including i) conventional non-specific extracellular fluid contrast agents for assessing tissue perfusion; ii) hepatobiliary-specific contrast agents that are taken up by functioning hepatocytes and excreted through the biliary system for evaluating hepatobiliary function; iii) superparamagnetic iron oxide particles that accumulate in Kupffer cells; and iv) novel molecular contrast agents that are biochemically targeted to specific molecular/cellular processes for staging liver diseases or detecting treatment responses. The use of different functional and molecular MRI methods enables the non-invasive assessment of disease burden, progression, and treatment response in a variety of liver diseases. A high diagnostic performance can be achieved with MRI by combining imaging biomarkers.

Simulation and navigation liver surgery: an update after 2,000 virtual hepatectomies

The advent of preoperative 3-dimensional (3D) simulation software has made a variety of unprecedented surgical simulations possible. Since 2004, we have performed more than 2,000 preoperative simulations in the University of Tokyo Hospital, and they have enabled us to obtain a great deal of information, such as the detailed shape of liver segments, the precise volume of each segment, and the volume of hepatic venous drainage areas. As a result, we have been able to perform more aggressive and complicated surgery safely. The next step is to create a navigation system that will accurately reproduce the preoperative plan. Real-time virtual sonography (RVS) is a navigation system that provides fusion images of ultrasonography and reconstructed computed tomography images or magnetic resonance images. The RVS system facilitates the surgeon's understanding of interpretation of ultrasound images and the detection of tumors that are difficult to find by ultrasound alone. In the near future, surgical navigation systems may evolve to the point where they will be able to inform surgeons intraoperatively in real time about not only intrahepatic structures, such as vessels and tumors, but also the portal territory, hepatic vein drainage areas, and resection lines that have been planned preoperatively.

Unusual Distribution Kinetics of Gadoxetate in Healthy Human Subjects Genotyped for OATP1B1: Application of Population Analysis and a Minimal Physiological-Based Pharmacokinetic Model

Gadoxetate (Gd-EOB-DTPA) is a hepatobiliary-specific contrast agent for magnetic resonance imaging. Using a minimal physiological-based pharmacokinetic (PBPK) model, it has been shown for the first time, that the rapid initial decline of plasma concentration after intravenous injection is the result of an uptake into hepatocytes rather than of a distribution into the extravascular extracellular space. About 50% of the steady-state distribution volume is related to hepatic uptake. The hepatic extraction ratio and hepatic clearance estimated based on the liver model as a part of the PBPK model were in accordance with literature data. The same holds for the predicted time course of the amount of gadoxetate in liver parenchyma. In elucidating the impact of OATP1B1 genotype (*1a/*1a and *15/*15) on the pharmacokinetics of gadoxetate, we found that tissue uptake and back-transfer rates were significantly reduced, whereas the hepatic sinusoidal efflux rate was significantly increased in carriers of the *15/*15 haplotype compared with those of the *1a/*1a (wild type). The model is potentially useful for determining hepatic kinetic parameters and distribution properties of drugs.

Evaluation of liver function using the hepatocyte enhancement fraction based on gadoxetic acid-enhanced MRI in patients with chronic hepatitis B

OBJECTIVES

This study aimed to evaluate the feasibility of using the hepatocyte enhancement fraction (HEF) based on gadoxetic acid-enhanced magnetic resonance imaging (MRI) for assessing the liver function in patients with chronic hepatitis B.

METHODS

Sixty patients with Child-Pugh grade A (CP-A), 18 with Child-Pugh grade B (CP-B), 2 with Child-Pugh grade C (CP-C), and 20 with normal liver function (NLF) were enrolled. Gadolinium ethoxybenzyldiethy-lenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI was conducted. T1 mapping imaging was performed before and 20 min after Gd-EOB-DTPA administration. The pre- and post-contrast T1 values of the liver (T1pre and T1post), increase in the T1 relaxation rate (ΔR1), rate of decrease in the T1 relaxation time (ΔT1), HEF, and uptake coefficient (K) parameters in the NLF, CP-A, and CP-B + CP-C groups were compared using one-way analysis of variance. The effectiveness of each parameter in differentiating the NLF + CP-A group from the CP-B + CP-C group was evaluated using the receiver operating characteristic (ROC) curve.

RESULTS

The HEF, K, ΔT1, and ΔR1 values decreased, while the T1post and T1pre values increased, with the increase in liver function damage. Significant differences in T1post, ΔT1, ΔR1, and HEF were found between different groups, except for the CP-A and NLF groups. However, no significant difference was observed in the T1pre among the three groups. HEF exhibited the largest area under the ROC curve.

CONCLUSION

The HEF is an effective method for evaluating liver function in patients with hepatitis B.

Prediction of post-hepatectomy liver failure using gadoxetic acid-enhanced magnetic resonance imaging for hepatocellular carcinoma with portal vein invasion

PURPOSE

Accurate prediction of post-hepatectomy liver failure (PHLF) is important in advanced hepatocellular carcinoma (HCC). We aimed to retrospectively evaluate the utility of gadoxetic acid-enhanced MRI for predicting PHLF in patients who underwent anatomic hepatectomy for HCC with portal vein invasion.

METHODS

Forty-one patients (32 men, 9 women) were included. Hepatobiliary-phase MR images were acquired 20 min after injection of gadoxetic acid using a 3D fat-suppressed T1-weighted spoiled gradient-echo sequence. Liver-spleen ratio (LSR), remnant hepatocellular uptake index (rHUI), and HUI were calculated. The severity of PHLF was defined according to the International Study Group of Liver Surgery. Differences in LSR between the resected liver and the remnant liver, and HUI and rHUI/HUI between no/mild and severe PHLF were compared using the Wilcoxon signed-rank test and Wilcoxon rank-sum test, respectively. Univariate and multivariate logistic regression analyses were performed to identify predictors of severe PHLF. Areas under the receiver operating characteristic curves (AUCs) of rHUI and rHUI/HUI were calculated for predicting severe PHLF.

RESULTS

Nine patients developed severe PHLF. LSR of the remnant liver was significantly higher than that of the resected liver (P < 0.001). Severe PHLF demonstrated significantly lower rHUI (P < 0.001) and rHUI/HUI (P < 0.001) compared with no/mild PHLF. Multivariate logistic regression analysis showed that decreased rHUI (P = 0.012, AUC=0.885) and rHUI/HUI (P = 0.002, AUC=0.852) were independent predictors of severe PHLF.

CONCLUSION

Gadoxetic acid-enhanced MRI can be a promising noninvasive examination for assessing global and regional liver function, allowing estimation of the functional liver remnant and accurate prediction of severe PHLF before hepatic resection.

Efficiency of regional functional liver volume assessment using Gd-EOB-DTPA-enhanced magnetic resonance imaging for hepatocellular carcinoma with portal vein tumor thrombus

PURPOSE

We investigated whether functional future remnant liver volume (fFRLV), assessed using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI), could evaluate regional liver function in hepatocellular carcinoma (HCC) patients with portal vein tumor thrombus (PVTT) and help establish the indication for hepatectomy.

METHODS

The subjects of this study were 12 patients with PVTT [PVTT(+) group] and 58 patients without PVTT [PVTT(-) group], from among 191 patients who underwent hepatectomy of more than one segment for HCC. We calculated the liver-to-muscle ratio (LMR) in the remnant liver, using EOB-MRI and fFRLV. Preoperative factors and surgical outcome were compared between the groups. The LMR of the area occluded by PVTT was compared with that of the non-occluded area.

RESULTS

The indocyanine green retention rate at 15 min (ICG-R15) and liver fibrosis indices were increased in the PVTT(+) group, but the surgical outcomes of patients in this group were acceptable, with no liver failure, no mortality, and no differences from those in the PVTT(-) group. The fFRLV in the PVTT(+) group was not significantly different from that in the PVTT(-) group (p = 0.663). The LMR was significantly lower in the occluded area than in the non-occluded area (p = 0.004), indicating decreased liver function.

CONCLUSION

Assessing fFRLV using EOB-MRI could be useful for evaluating regional liver function and establishing operative indications for HCC with PVTT.

Hepatic uptake index in the hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriamine penta acetic acid-enhanced magnetic resonance imaging estimates functional liver reserve and predicts post-hepatectomy liver failure

BACKGROUND

Recent evidence suggests that gadolinium ethoxybenzyl diethylenetriamine penta acetic acid-enhanced (Gd-EOB-DTPA) magnetic resonance imaging may be used to evaluate liver function. The aim of this study was to assess whether the signal intensity of Gd-EOB-DTPA magnetic resonance imaging may be used to predict functional liver reserve and posthepatectomy liver failure in patients undergoing hepatectomy for liver tumors.

METHODS

This is an observational retrospective study on 137 preoperative Gd-EOB-DTPA magnetic resonance imaging of patients undergoing hepatectomy between 2015 and 2018. Mean signal intensity of liver (L₂₀) and spleen (S₂₀) were measured on T1-weighted single-breath-hold 3-dimensional fat-saturated gradient echo sequences acquired 20 minutes after Gd-EOB-DTPA administration. The hepatocellular uptake index of liver volume (V_L) was calculated with the formula V_L([L₂₀/S₂₀] - 1) and was tested with several score systems for liver diseases and to the occurrence of post-hepatectomy liver failure.

RESULTS

Patients with diseased liver had significantly lower values of hepatic uptake index in comparison with those with normal function. This was found for a Model for End-Stage Liver Disease score ≤9 versus >9 (P = .04), combination of bilirubin and cholinesterases levels score ≤2 versus >2 (P = .02), albumin to bilirubin grades (P = .03), and Humanitas score ≤6 versus >6 (P = .03). Twenty-two patients (16%) developed posthepatectomy liver failure, and 2 (1.4%) died within 90 days. The hepatocellular uptake index was significantly lower in those patients with posthepatectomy liver failure (P < .01). Receiver operating characteristics curve analysis revealed valuable hepatocellular uptake index ability in predicting post-hepatectomy liver failure (area under the curve = 0.84; 95% confidence interval, 0.71-0.92; P < .01), with a cutoff value of 574.33 (98% sensitivity; 83% specificity).

CONCLUSION

The hepatocellular uptake index hepatocellular uptake index measured on preoperative Gd-EOB-DTPA magnetic resonance imaging identifies patients with diseased liver and predicts posthepatectomy liver failure. This index could be used to discern those patients at higher risk of complications after hepatectomy.

Radiomics model based on preoperative gadoxetic acid-enhanced MRI for predicting liver failure

BACKGROUND

Postoperative liver failure is the most severe complication in cirrhotic patients with hepatocellular carcinoma (HCC) after major hepatectomy. Current available clinical indexes predicting postoperative residual liver function are not sufficiently accurate.

AIM

To determine a radiomics model based on preoperative gadoxetic acid-enhanced magnetic resonance imaging for predicting liver failure in cirrhotic patients with HCC after major hepatectomy.

METHODS

For this retrospective study, a radiomics-based model was developed based on preoperative hepatobiliary phase gadoxetic acid-enhanced magnetic resonance images in 101 patients with HCC between June 2012 and June 2018. Sixty-one radiomic features were extracted from hepatobiliary phase images and selected by the least absolute shrinkage and selection operator method to construct a radiomics signature. A clinical prediction model, and radiomics-based model incorporating significant clinical indexes and radiomics signature were built using multivariable logistic regression analysis. The integrated radiomics-based model was presented as a radiomics nomogram. The performances of clinical prediction model, radiomics signature, and radiomics-based model for predicting post-operative liver failure were determined using receiver operating characteristics curve, calibration curve, and decision curve analyses.

RESULTS

Five radiomics features from hepatobiliary phase images were selected to construct the radiomics signature. The clinical prediction model, radiomics signature, and radiomics-based model incorporating indocyanine green clearance rate at 15 min and radiomics signature showed favorable performance for predicting postoperative liver failure (area under the curve: 0.809-0.894). The radiomics-based model achieved the highest performance for predicting liver failure (area under the curve: 0.894; 95%CI: 0.823-0.964). The integrated discrimination improvement analysis showed a significant improvement in the accuracy of liver failure prediction when radiomics signature was added to the clinical prediction model (integrated discrimination improvement = 0.117, P = 0.002). The calibration curve and an insignificant Hosmer-Lemeshow test statistic (P = 0.841) demonstrated good calibration of the radiomics-based model. The decision curve analysis showed that patients would benefit more from a radiomics-based prediction model than from a clinical prediction model and radiomics signature alone.

CONCLUSION

A radiomics-based model of preoperative gadoxetic acid–enhanced MRI can be used to predict liver failure in cirrhotic patients with HCC after major hepatectomy.