Volume-assisted estimation of liver function based on Gd-EOB-DTPA-enhanced MR relaxometry. Eur Radiol. 2016;26:1125-1133. [PMID: 26186960 DOI: 10.1007/s00330-015-3919-5]

Predicting post-hepatectomy liver failure with T1 mapping-based whole-liver histogram analysis on gadoxetic acid-enhanced MRI: comparison with the indocyanine green clearance test and albumin-bilirubin scoring system

OBJECTIVES

To explore the value of T1 mapping-based whole-liver histogram analysis on gadoxetic acid-enhanced MRI for predicting post-hepatectomy liver failure (PHLF).

METHODS

Consecutive patients from March 2016 to March 2018 who underwent gadoxetic acid-enhanced MRI in our hospital were retrospectively analyzed, and 37 patients were enrolled. Whole-liver T1 mapping-based histogram analysis was performed. The indocyanine green (ICG) clearance tests were performed, and albumin-bilirubin (ALBI) scores were calculated. Univariate and multivariate binary logistic analyses were performed to identify independent predictors for PHLF. Diagnostic performance was evaluated with ROC analysis. Histogram-extracted parameters were also associated with the ICG test and ALBI scoring system.

RESULTS

In enrolled 37 patients (age 57.19 ± 12.28 years), 28 were male. 35.1% (13/37) of patients developed PHLF. For univariate analysis, pre-contrast T1 relaxation time (T1pre) mean, T1pre 95th percentile, the standard deviation (SD) of T1 relaxation time in hepatobiliary phase (T1HBP SD), T1HBP 95th percentile, T1HBP kurtosis, and ICG percentage retained at 15 min (ICG-R15) showed significant differences between the PHLF and non-PHLF groups (all p < 0.05), whereas the ALBI scores showed no significant differences between the two groups (p = 0.937). Multivariate analysis showed that a higher T1HBP 95th percentile was the independent predictor for PHLF (p < 0.05; odds ratio (OR) = 1.014). In addition, most of the histogram-extracted parameters showed significant correlations to the ICG test.

CONCLUSIONS

T1 mapping-based whole-liver histogram analysis on gadoxetic acid-enhanced MRI is valuable for PHLF prediction and risk stratification, which outperformed the ICG clearance test and ALBI scoring system.

KEY POINTS

Question What is the value of T1 mapping-based whole-liver histogram analysis on gadoxetic acid-enhanced MRI for PHLF? Findings The histogram parameters extracted from gadoxetic acid-enhanced T1 mapping manifested potential for grading liver function preoperatively. Clinical relevance T1 mapping-based whole-liver histogram analysis on gadoxetic acid-enhanced MRI can serve as a convenient one-station radiological tool to help identify potential PHLF risks within the preoperative clinical decision-making framework.

Predicting post-hepatectomy liver failure in patients with hepatocellular carcinoma: nomograms based on deep learning analysis of gadoxetic acid-enhanced MRI

OBJECTIVES

This study aimed to develop nomograms for predicting post-hepatectomy liver failure (PHLF) in patients with hepatocellular carcinoma (HCC), using deep learning analysis of Gadoxetic acid-enhanced hepatobiliary (HBP) MRI.

METHODS

This retrospective study analyzed patients who underwent gadoxetic acid-enhanced MRI and hepatectomy for HCC between 2016 and 2020 at two referral centers. Using a deep learning algorithm, volumes and signal intensities of whole non-tumor liver, expected remnant liver, and spleen were measured on HBP images. Two multivariable logistic regression models were formulated to predict PHLF, defined and graded by the International Study Group of Liver Surgery: one based on whole non-tumor liver measurements (whole liver model) and the other on expected remnant liver measurements (remnant liver model). The models were presented as nomograms and a web-based calculator. Discrimination performance was evaluated using the area under the receiver operating curve (AUC), with internal validation through 1000-fold bootstrapping.

RESULTS

The study included 1760 patients (1395 male; mean age ± standard deviation, 60 ± 10 years), with 137 (7.8%) developing PHLF. Nomogram predictors included sex, gamma-glutamyl transpeptidase, prothrombin time international normalized ratio, platelets, extent of liver resection, and MRI variables derived from the liver volume, liver-to-spleen signal intensity ratio, and spleen volume. The whole liver and the remnant liver nomograms demonstrated strong predictive performance for PHLF (optimism-corrected AUC of 0.78 and 0.81, respectively) and symptomatic (grades B and C) PHLF (optimism-corrected AUC of 0.81 and 0.84, respectively).

CONCLUSION

Nomograms based on deep learning analysis of gadoxetic acid-enhanced HBP images accurately stratify the risk of PHLF.

KEY POINTS

Question Can PHLF be predicted by integrating clinical and MRI-derived volume and functional variables through deep learning analysis of gadoxetic acid-enhanced MRI? Findings Whole liver and remnant liver nomograms demonstrated strong predictive performance for PHLF with the optimism-corrected area under the curve of 0.78 and 0.81, respectively. Clinical relevance These nomograms can effectively stratify the risk of PHLF, providing a valuable tool for treatment decisions regarding hepatectomy for HCC.

Liver function estimation using multiphase hepatic CT: diagnostic performance of iodine-uptake and volumetric parameters

OBJECTIVES

To investigate whether multiphase hepatic CT can predict liver function measured with indocyanine-green-retention test (ICG-R15) and identify patients with severe liver dysfunction contraindicating major hepatectomy, defined as ICG-R15 ≥ 20%, compared to technetium-99m-galactosyl serum albumin (99mTc-GSA) scintigraphy.

MATERIALS AND METHODS

This retrospective study included 118 patients (84 men, mean age, 69.4 ± 11.3 years) who underwent ICG-R15, 99mTc-GSA, and multi-phase CT including early portal-venous-phase and 3-min delayed-phase. CT-derived extracellular volume fraction (ECV), iodine washout rate (IWR), liver and spleen volumes normalized by body-surface-area (LV/BSA and SpV/BSA, respectively), and 99mTc-GSA-derived blood clearance index (HH15) and liver receptor index (LHL15) were quantified. Each parameter was compared between ICG-R15 ≥ 20% (n = 22) and ICG-R15 < 20% (n = 96) groups. Correlations with ICG-R15 were analyzed. The diagnostic performance to predict ICG-R15 ≥ 20% was assessed with areas under the receiver operating characteristic curve (AUC). Multivariable logistic regression analysis was used to identify independent CT predictors, and combined performance was determined.

RESULTS

In the ICG-R15 ≥ 20% group, IWR (p < 0.001), LV/BSA (p = 0.026), LHL15 (p < 0.001) were lower and ECV (p = 0.001), SpV/BSA (p = 0.005), and HH15 (p < 0.001) were higher compared to ICG-R15 < 20% group. ICG-R15 showed positive correlations with ECV (r = 0.355), SpV/BSA (r = 0.248), and HH15 (r = 0.385), while negative correlations with IWR (r = -0.523), LV/BSA (r = -0.123, not statistically significant), and LHL15 (r = -0.504). The AUC of ECV, IWR, LV/BSA, SpV/BSA, HH15, and LHL15 were 0.719, 0.845, 0.653, 0.694, 0.844, and 0.878, respectively. IWR, SpV/BSA, and LV/BSA were independent predictors, with a combined AUC of 0.924.

CONCLUSION

IWR predicted liver function better than ECV and hepatosplenic volumetry. The combined IWR and volumetry yielded an accurate prediction of severe liver dysfunction.

KEY POINTS

Question Despite the widespread use of multiphase CT in patients with hepatobiliary diseases, its potential role in assessing liver function has been scarcely evaluated. Findings Iodine washout rate (IWR), liver volume indexed by body surface area, and spleen volume indexed by body surface area were independent predictors for severe liver dysfunction. Clinical relevance Combined IWR and hepatosplenic volumetry on routine hepatic CT may help assess hepatic function for optimizing treatment strategies and predicting patient prognosis.

Free-breathing, fat-corrected T1 mapping of the liver with stack-of-stars MRI, and joint estimation of T1, PDFF, R 2 * , and B 1 +

PURPOSE

Quantitative T1 mapping has the potential to replace biopsy for noninvasive diagnosis and quantitative staging of chronic liver disease. Conventional T1 mapping methods are confounded by fat andB 1 + $$ {B}_1^{+} $$ inhomogeneities, resulting in unreliable T1 estimations. Furthermore, these methods trade off spatial resolution and volumetric coverage for shorter acquisitions with only a few images obtained within a breath-hold. This work proposes a novel, volumetric (3D), free-breathing T1 mapping method to account for multiple confounding factors in a single acquisition.

THEORY AND METHODS

Free-breathing, confounder-corrected T1 mapping was achieved through the combination of non-Cartesian imaging, magnetization preparation, chemical shift encoding, and a variable flip angle acquisition. A subspace-constrained, locally low-rank image reconstruction algorithm was employed for image reconstruction. The accuracy of the proposed method was evaluated through numerical simulations and phantom experiments with a T1/proton density fat fraction phantom at 3.0 T. Further, the feasibility of the proposed method was investigated through contrast-enhanced imaging in healthy volunteers, also at 3.0 T.

RESULTS

The method showed excellent agreement with reference measurements in phantoms across a wide range of T1 values (200 to 1000 ms, slope = 0.998 (95% confidence interval (CI) [0.963 to 1.035]), intercept = 27.1 ms (95% CI [0.4 54.6]), r2 = 0.996), and a high level of repeatability. In vivo imaging studies demonstrated moderate agreement (slope = 1.099 (95% CI [1.067 to 1.132]), intercept = -96.3 ms (95% CI [-82.1 to -110.5]), r2 = 0.981) compared to saturation recovery-based T1 maps.

CONCLUSION

The proposed method produces whole-liver, confounder-corrected T1 maps through simultaneous estimation of T1, proton density fat fraction, andB 1 + $$ {B}_1^{+} $$ in a single, free-breathing acquisition and has excellent agreement with reference measurements in phantoms.

A Novel Method Using Gadolinium-Ethoxybenzyl Diethylenetriamine Pentaacetate Acid-Enhanced Magnetic Resonance Imaging for Predicting Post-Hepatectomy Liver Failure in Hepatocellular Carcinoma Patients with a Major Portal Vein Tumor Thrombus

INTRODUCTION

The usefulness of gadolinium-ethoxybenzyl diethylenetriamine pentaacetate acid-enhanced magnetic resonance imaging (EOB-MRI) in assessing the functional future remnant liver volume (fFRLV) to predict post-hepatectomy liver failure (PHLF) has been previously reported. Herein, we evaluated the efficacy of this technique in patients with hepatocellular carcinoma (HCC) with a major portal vein tumor thrombus (PVTT).

METHODS

This study included 21 patients with PVTT in the ipsilateral first-order branch (Vp3) and 30 patients with PVTT in the main trunk/contralateral branch (Vp4). To evaluate fFRLV, the signal intensity (SI) of the remnant liver was determined on T1-weighted images, using both conventional and newly developed methods. The fFRLV was calculated using the SI of the remnant liver and muscle, remnant liver volume, and body surface area. Preoperative factors predicting PHLF (≥grade B) in HCC patients with Vp3/4 PVTT were evaluated.

RESULTS

In the Vp3 group, we found fFRLV area under the receiver-operating characteristic curves (AUCs) above 0.70 (AUC = 0.875, 0.750) using EOB-MRI results calculated using either the plot or whole method. None of the parameters in the Vp4 group had an AUC greater than 0.70.

CONCLUSION

The fFRLV calculated by EOB-MRI using the whole method can be as useful as the conventional method in predicting PHLF (≥grade B) for HCC patients with Vp3 PVTT.

Role of intelligent/interactive qualitative and quantitative analysis-three-dimensional estimated model in donor-recipient size mismatch following deceased donor liver transplantation

BACKGROUND

Donor-recipient size mismatch (DRSM) is considered a crucial factor for poor outcomes in liver transplantation (LT) because of complications, such as massive intraoperative blood loss (IBL) and early allograft dysfunction (EAD). Liver volumetry is performed routinely in living donor LT, but rarely in deceased donor LT (DDLT), which amplifies the adverse effects of DRSM in DDLT. Due to the various shortcomings of traditional manual liver volumetry and formula methods, a feasible model based on intelligent/interactive qualitative and quantitative analysis-three-dimensional (IQQA-3D) for estimating the degree of DRSM is needed.

AIM

To identify benefits of IQQA-3D liver volumetry in DDLT and establish an estimation model to guide perioperative management.

METHODS

We retrospectively determined the accuracy of IQQA-3D liver volumetry for standard total liver volume (TLV) (sTLV) and established an estimation TLV (eTLV) index (eTLVi) model. Receiver operating characteristic (ROC) curves were drawn to detect the optimal cut-off values for predicting massive IBL and EAD in DDLT using donor sTLV to recipient sTLV (called sTLVi). The factors influencing the occurrence of massive IBL and EAD were explored through logistic regression analysis. Finally, the eTLVi model was compared with the sTLVi model through the ROC curve for verification.

RESULTS

A total of 133 patients were included in the analysis. The Changzheng formula was accurate for calculating donor sTLV (P = 0.083) but not for recipient sTLV (P = 0.036). Recipient eTLV calculated using IQQA-3D highly matched with recipient sTLV (P = 0.221). Alcoholic liver disease, gastrointestinal bleeding, and sTLVi > 1.24 were independent risk factors for massive IBL, and drug-induced liver failure was an independent protective factor for massive IBL. Male donor-female recipient combination, model for end-stage liver disease score, sTLVi ≤ 0.85, and sTLVi ≥ 1.32 were independent risk factors for EAD, and viral hepatitis was an independent protective factor for EAD. The overall survival of patients in the 0.85 < sTLVi < 1.32 group was better compared to the sTLVi ≤ 0.85 group and sTLVi ≥ 1.32 group (P < 0.001). There was no statistically significant difference in the area under the curve of the sTLVi model and IQQA-3D eTLVi model in the detection of massive IBL and EAD (all P > 0.05).

CONCLUSION

IQQA-3D eTLVi model has high accuracy in predicting massive IBL and EAD in DDLT. We should follow the guidance of the IQQA-3D eTLVi model in perioperative management.

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.

Volume-Assisted Estimation of Remnant Liver Function Based on Gd-EOB-DTPA Enhanced MR Relaxometry: A Prospective Observational Trial

In the context of liver surgery, predicting postoperative liver dysfunction is essential. This study explored the potential of preoperative liver function assessment by MRI for predicting postoperative liver dysfunction and compared these results with the established indocyanine green (ICG) clearance test. This prospective study included patients undergoing liver resection with preoperative MRI planning. Liver function was quantified using T1 relaxometry and correlated with established liver function scores. The analysis revealed an improved model for predicting postoperative liver dysfunction, exhibiting an accuracy (ACC) of 0.79, surpassing the 0.70 of the preoperative ICG test, alongside a higher area under the curve (0.75). Notably, the proposed model also successfully predicted all cases of liver failure and showed potential in predicting liver synthesis dysfunction (ACC 0.78). This model showed promise in patient survival rates with a Hazard ratio of 0.87, underscoring its potential as a valuable tool for preoperative evaluation. The findings imply that MRI-based assessment of liver function can provide significant benefits in the early identification and management of patients at risk for postoperative liver dysfunction.

CT-derived extracellular volume and liver volumetry can predict posthepatectomy liver failure in hepatocellular carcinoma

OBJECTIVES

Posthepatectomy liver failure (PHLF) is a severe complication of liver resection. We aimed to develop and validate a model based on extracellular volume (ECV) and liver volumetry derived from computed tomography (CT) for preoperative predicting PHLF in resectable hepatocellular carcinoma (HCC) patients.

METHODS

A total of 393 resectable HCC patients from two hospitals were enrolled and underwent multiphasic contrast-enhanced CT before surgery. A total of 281 patients from our hospital were randomly divided into a training cohort (n = 181) and an internal validation cohort (n = 100), and 112 patients from another hospital formed the external validation cohort. CT-derived ECV was measured on nonenhanced and equilibrium phase images, and liver volumetry was measured on portal phase images. The model is composed of independent predictors of PHLF. The under the receiver operator characteristic curve (AUC) and calibration curve were used to reflect the predictive performance and calibration of the model. Comparison of AUCs used the DeLong test.

RESULTS

CT-derived ECV, measured future liver remnant (mFLR) ratio, and serum albumin were independent predictors for PHLF in resectable HCC patients. The AUC of the model was significantly higher than that of the ALBI score in the training cohort, internal validation cohort, and external validation cohort (all p < 0.001). The calibration curve of the model showed good consistency in the training cohort and the internal and external validation cohorts.

CONCLUSIONS

The novel model contributes to the preoperative prediction of PHLF in resectable HCC patients.

CRITICAL RELEVANCE STATEMENT

The novel model combined CT-derived extracellular volume, measured future liver remnant ratio, and serum albumin outperforms the albumin-bilirubin score for predicting posthepatectomy liver failure in patients with resectable hepatocellular carcinoma.

KEY POINTS

• CT-derived ECV correlated well with the fibrosis stage of the background liver. • CT-derived ECV and mFLR ratio were independent predictors for PHLF in HCC. • The AUC of the model was higher than the CT-derived ECV and mFLR ratio. • The model showed a superior predictive performance than that of the ALBI score.

Intravoxel incoherent motion diffusion weighted imaging for preoperative evaluation of liver regeneration after hepatectomy in hepatocellular carcinoma

OBJECTIVES

To explore whether intravoxel incoherent motion (IVIM) parameters could evaluate liver regeneration preoperatively.

METHODS

A total of 175 HCC patients were initially recruited. The apparent diffusion coefficient, true diffusion coefficient (D), pseudodiffusion coefficient (D*), pseudodiffusion fraction (f), diffusion distribution coefficient, and diffusion heterogeneity index (Alpha) were measured by two independent radiologists. Spearman's correlation test was used to assess correlations between IVIM parameters and the regeneration index (RI), calculated as 100% × (the volume of the postoperative remnant liver - the volume of the preoperative remnant liver) / the volume of the preoperative remnant liver. Multivariate linear regression analyses were used to identify the factors for RI.

RESULTS

Finally, 54 HCC patients (45 men and 9 women, mean age 51.26 ± 10.41 years) were retrospectively analyzed. The intraclass correlation coefficient ranged from 0.842 to 0.918. In all patients, fibrosis stage was reclassified as F0-1 (n = 10), F2-3 (n = 26), and F4 (n = 18) using the METAVIR system. Spearman correlation test showed D* (r = 0.303, p = 0.026) was associated with RI; however, multivariate analysis showed that only D value was a significant predictor (p < 0.05) of RI. D and D*showed moderate correlations with fibrosis stage (r = -0.361, p = 0.007; r = -0.457, p = 0.001). Fibrosis stage showed a negative correlation with RI (r = -0.263, p = 0.015). In the 29 patients who underwent minor hepatectomy, only the D value showed a positive association (p < 0.05) with RI, and a negative correlation with fibrosis stage (r = -0.360, p = 0.018). However, in the 25 patients who underwent major hepatectomy, no IVIM parameters were associated with RI (p > 0.05).

CONCLUSIONS

The D and D* values, especially the D value, may be reliable preoperative predictors of liver regeneration.

KEY POINTS

• The D and D* values, especially the D value, derived from IVIM diffusion-weighted imaging may be useful markers for the preoperative prediction of liver regeneration in patients with HCC. • The D and D* values derived from IVIM diffusion-weighted imaging show significant negative correlations with fibrosis, an important predictor of liver regeneration. • No IVIM parameters were associated with liver regeneration in patients who underwent major hepatectomy, but the D value was a significant predictor of liver regeneration in patients who underwent minor hepatectomy.

Confounder-corrected T1 mapping in the liver through simultaneous estimation of T1 , PDFF, R 2 * , and B 1 + in a single breath-hold acquisition

PURPOSE

Quantitative volumetric T₁ mapping in the liver has the potential to aid in the detection, diagnosis, and quantification of liver fibrosis, inflammation, and spatially resolved liver function. However, accurate measurement of hepatic T₁ is confounded by the presence of fat and inhomogeneous B 1 + $$ {B}_1^{+} $$ excitation. Furthermore, scan time constraints related to respiratory motion require tradeoffs of reduced volumetric coverage and/or increased acquisition time. This work presents a novel 3D acquisition and estimation method for confounder-corrected T₁ measurement over the entire liver within a single breath-hold through simultaneous estimation of T₁ , fat and B 1 + $$ {B}_1^{+} $$ .

THEORY AND METHODS

The proposed method combines chemical shift encoded MRI and variable flip angle MRI with a B 1 + $$ {B}_1^{+} $$ mapping technique to enable confounder-corrected T₁ mapping. The method was evaluated theoretically and demonstrated in both phantom and in vivo acquisitions at 1.5 and 3.0T. At 1.5T, the method was evaluated both pre- and post- contrast enhancement in healthy volunteers.

RESULTS

The proposed method demonstrated excellent linear agreement with reference inversion-recovery spin-echo based T₁ in phantom acquisitions at both 1.5 and 3.0T, with minimal bias (5.2 and 45 ms, respectively) over T₁ ranging from 200-1200 ms. In vivo results were in general agreement with reference saturation-recovery based 2D T₁ maps (SMART₁ Map, GE Healthcare).

CONCLUSION

The proposed 3D T₁ mapping method accounts for fat and B 1 + $$ {B}_1^{+} $$ confounders through simultaneous estimation of T₁ , B 1 + $$ {B}_1^{+} $$ , PDFF and R 2 * $$ {R}_2^{\ast } $$ . It demonstrates strong linear agreement with reference T₁ measurements, with low bias and high precision, and can achieve full liver coverage in a single breath-hold.

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.

Water-Fat Separated T1 Mapping in the Liver and Correlation to Hepatic Fat Fraction

(1) Background: T1 mapping in magnetic resonance imaging (MRI) of the liver has been proposed to estimate liver function or to detect the stage of liver disease, among others. Thus far, the impact of intrahepatic fat on T1 quantification has only been sparsely discussed. Therefore, the aim of this study was to evaluate the potential of water-fat separated T1 mapping of the liver. (2) Methods: A total of 386 patients underwent MRI of the liver at 3 T. In addition to routine imaging techniques, a 3D variable flip angle (VFA) gradient echo technique combined with a two-point Dixon method was acquired to calculate T1 maps from an in-phase (T1_in) and water-only (T1_W) signal. The results were correlated with proton density fat fraction using multi-echo 3D gradient echo imaging (PDFF) and multi-echo single voxel spectroscopy (PDFF_MRS). Using T1_in and T1_W, a novel parameter FF_T1 was defined and compared with PDFF and PDFF_MRS. Furthermore, the value of retrospectively calculated T1_W (T1_W_calc) based on T1_in and PDFF was assessed. Wilcoxon test, Pearson correlation coefficient and Bland-Altman analysis were applied as statistical tools. (3) Results: T1_in was significantly shorter than T1_W and the difference of both T1 values was correlated with PDFF (R = 0.890). FF_T1 was significantly correlated with PDFF (R = 0.930) and PDFF_MRS (R = 0.922) and yielded only minor bias compared to both established PDFF methods (0.78 and 0.21). T1_W and T1_W_calc were also significantly correlated (R = 0.986). (4) Conclusion: T1_W acquired with a water-fat separated VFA technique allows to minimize the influence of fat on liver T1. Alternatively, T1_W can be estimated retrospectively from T1_in and PDFF, if a Dixon technique is not available for T1 mapping.

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.

Noninvasive imaging of hepatic dysfunction: A state-of-the-art review

Hepatic dysfunction represents a wide spectrum of pathological changes, which can be frequently found in hepatitis, cholestasis, metabolic diseases, and focal liver lesions. As hepatic dysfunction is often clinically silent until advanced stages, there remains an unmet need to identify affected patients at early stages to enable individualized intervention which can improve prognosis. Passive liver function tests include biochemical parameters and clinical grading systems (e.g., the Child-Pugh score and Model for End-Stage Liver Disease score). Despite widely used and readily available, these approaches provide indirect and limited information regarding hepatic function. Dynamic quantitative tests of liver function are based on clearance capacity tests such as the indocyanine green (ICG) clearance test. However, controversial results have been reported for the ICG clearance test in relation with clinical outcome and the accuracy is easily affected by various factors. Imaging techniques, including ultrasound, computed tomography, and magnetic resonance imaging, allow morphological and functional assessment of the entire hepatobiliary system, hence demonstrating great potential in evaluating hepatic dysfunction noninvasively. In this article, we provide a state-of-the-art summary of noninvasive imaging modalities for hepatic dysfunction assessment along the pathophysiological track, with special emphasis on the imaging modality comparison and selection for each clinical scenario.

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.

Gadoxetic Acid Uptake Rate as a Measure of Global and Regional Liver Function as Compared to Indocyanine Green Retention, Albumin-Bilirubin Score, and Portal Venous Perfusion

Purpose

Global and regional liver function assessments are important for defining the magnitude and spatial distribution of dose to preserve functional liver parenchyma and reduce incidence of hepatotoxicity from radiation therapy for intrahepatic cancer treatment. This individualized liver function-guided radiation therapy strategy is critical for patients with heterogeneous and poor liver function, often observed in cirrhotic patients treated for hepatocellular carcinoma. This study aimed to validate k₁ as a measure of global and regional function through comparison with 2 well-regarded global function measures: indocyanine green retention (ICGR) and albumin-bilirubin (ALBI).

Methods and Materials

Seventy-nine dynamic gadoxetic acid enhanced magnetic resonance imaging scans were acquired in 40 patients with hepatocellular carcinoma in institutional review board approved prospective protocols. Portal venous perfusion (k_pv) was quantified from gadoxetic acid enhanced magnetic resonance imaging using a dual-input 2-compartment model, and gadoxetic acid uptake rate (k₁) was fitted using a linearized single-input 2-compartment model chosen for robust k₁ estimation. Four image-derived measures of global liver function were tested: (1) mean k₁ multiplied by liver volume (k₁V_L) (functional volume), (2) mean k₁ multiplied by blood distribution volume (k₁V_dis)_, (3) mean k_pv, and (4) liver volume (V_L). The measure's correlation with corresponding ICGR and ALBI tests was assessed using linear regression. Voxel-wise similarity between k₁ and k_pv was compared using Spearman ranked correlation.

Results

Significant correlations (P < .05) with ICGR and ALBI were found for k₁V_L, k₁V_dis, and V_L (in order of strength), but not for mean k_pv. The mean ranked correlation coefficient between k₁ and k_pv maps was 0.09. k₁ and k_pv maps were predominantly mismatched in patients with poor liver function.

Conclusions

The metric combining function and liver volume (k₁V_L) was a stronger measure of global liver function compared with perfusion or liver volume alone, especially in patients with poor liver function. Gadoxetic acid uptake rate is promising for both global and regional liver function.

Physiologically Based Modeling of the Effect of Physiological and Anthropometric Variability on Indocyanine Green Based Liver Function Tests

Accurate evaluation of liver function is a central task in hepatology. Dynamic liver function tests (DLFT) based on the time-dependent elimination of a test substance provide an important tool for such a functional assessment. These tests are used in the diagnosis and monitoring of liver disease as well as in the planning of hepatobiliary surgery. A key challenge in the evaluation of liver function with DLFTs is the large inter-individual variability. Indocyanine green (ICG) is a widely applied test compound used for the evaluation of liver function. After an intravenous administration, pharmacokinetic (PK) parameters are calculated from the plasma disappearance curve of ICG which provide an estimate of liver function. The hepatic elimination of ICG is affected by physiological factors such as hepatic blood flow or binding of ICG to plasma proteins, anthropometric factors such as body weight, age, and sex, or the protein amount of the organic anion-transporting polypeptide 1B3 (OATP1B3) mediating the hepatic uptake of ICG. Being able to account for and better understand these various sources of inter-individual variability would allow to improve the power of ICG based DLFTs and move toward an individualized evaluation of liver function. Within this work we systematically analyzed the effect of various factors on ICG elimination by the means of computational modeling. For the analysis, a recently developed and validated physiologically based pharmacokinetics (PBPK) model of ICG distribution and hepatic elimination was utilized. Key results are (i) a systematic analysis of the variability in ICG elimination due to hepatic blood flow, cardiac output, OATP1B3 abundance, liver volume, body weight and plasma bilirubin level; (ii) the evaluation of the inter-individual variability in ICG elimination via a large in silico cohort of n = 100,000 subjects based on the NHANES cohort with special focus on stratification by age, sex, and body weight; (iii) the evaluation of the effect of various degrees of cirrhosis on variability in ICG elimination. The presented results are an important step toward individualizing liver function tests by elucidating the effects of confounding physiological and anthropometric parameters in the evaluation of liver function via ICG.

Predictive value of combined computed tomography volumetry and magnetic resonance elastography for major complications after liver resection

PURPOSE

To retrospectively compare the predictive value of computed tomography volumetry (CTV), magnetic resonance elastography (MRE) of the liver, and their combination for major complications after liver resection.

METHODS

We enrolled 108 consecutive patients who underwent anatomical liver resection for liver tumors and preoperative contrast-enhanced CT and MRE. The future liver remnant (FLR) ratio was calculated by CTV, while the liver stiffness measurement (LSM) was obtained by MRE. FLR ratio alone, LSM alone, and combined FLR ratio and LSM were evaluated to predict major complications (Clavien-Dindo grade ≥ IIIa). Univariate and multivariate analyses of hepatic biochemical parameters and imaging data were performed to identify predictors of major complications. Receiver operating characteristic analyses of FLR ratio, LSM, and their combination were performed, and the sensitivity and specificity were calculated.

RESULTS

Twenty-two (20.4%) of the 108 patients experienced major complications. According to multiple regression analysis, the FLR ratio (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.91-0.99, p = 0.040) and LSM (OR 1.72, 95% CI 1.01-2.94, p = 0.047) were independent predictors of major complications. The combined FLR ratio and LSM were predictive of major complications, with an area under the curve (AUC) of 0.818, sensitivity of 68.2%, and specificity of 84.9%. The AUC and specificity for combined FLR ratio and LSM were larger than those for FLR ratio (AUC: 0.711, specificity: 80.2%) and LSM (AUC: 0.793, specificity: 80.2%).

CONCLUSION

Combined CTV and MRE analysis can improve the AUC and specificity for predicting major complications after anatomical liver resection.

Prediction of Remnant Liver Regeneration after Right Hepatectomy in Patients with Hepatocellular Carcinoma Using Preoperative CT Texture Analysis and Clinical Features

OBJECTIVES

To predict the regenerative rate of liver in patients with HCCs after right hepatectomy using texture analysis on preoperative CT combined with clinical features.

MATERIALS AND METHODS

88 patients with 90 HCCs who underwent right hepatectomy were retrospectively included. The future remnant liver was semiautomatically segmented, and the volume of future remnant liver on preoperative CT (LVpre) and the volume of remnant liver on following-up CT (LVfu) were measured. We calculated the regeneration index (RI) by the following equation: (LVfu - LVpre)/LVpre) × 100 (%). The support vector machine recursive method was used for the feature selection. The Naive Bayes classifier was used to predict liver RI, and 5-fold cross-validation was performed to adjust the parameters. Sensitivity, specificity, and accuracy were calculated to evaluate the diagnostic efficiency of the model.

RESULTS

The mean RI was 142.99 ± 92.17%. Of all clinical parameters and texture features, the AST, ALB, PT-INR, Perc.10%, and S(5, -5)Correlat were found to be statistically significant with RI. The diagnostic sensitivity, specificity, and accuracy of the model in the training group were 0.902, 0.634, and 0.768, and the AUC value of the obtained model was 0.841. In the test group, the sensitivity, specificity, and accuracy of the model were 1.0, 0.429, and 0.778, respectively, and the AUC value was 0.844.

CONCLUSION

The use of texture analysis on preoperative CT combined with clinical features can be helpful in predicting the liver regeneration rate in patients with HCCs after right hepatectomy.

Imaging-Based Staging of Hepatic Fibrosis in Patients with Hepatitis B: A Dynamic Radiomics Model Based on Gd-EOB-DTPA-Enhanced MRI

Accurate grading of liver fibrosis can effectively assess the severity of liver disease and help doctors make an appropriate diagnosis. This study aimed to perform the automatic staging of hepatic fibrosis on patients with hepatitis B, who underwent gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging with dynamic radiomics analysis. The proposed dynamic radiomics model combined imaging features from multi-phase dynamic contrast-enhanced (DCE) images and time-domain information. Imaging features were extracted from the deep learning-based segmented liver volume, and time-domain features were further explored to analyze the variation in features during contrast enhancement. Model construction and evaluation were based on a 132-case data set. The proposed model achieved remarkable performance in significant fibrosis (fibrosis stage S1 vs. S2-S4; accuracy (ACC) = 0.875, area under the curve (AUC) = 0.867), advanced fibrosis (S1-S2 vs. S3-S4; ACC = 0.825, AUC = 0.874), and cirrhosis (S1-S3 vs. S4; ACC = 0.850, AUC = 0.900) classifications in the test set. It was more dominant compared with the conventional single-phase or multi-phase DCE-based radiomics models, normalized liver enhancement, and some serological indicators. Time-domain features were found to play an important role in the classification models. The dynamic radiomics model can be applied for highly accurate automatic hepatic fibrosis staging.

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.

New Advances in Magnetic Resonance Techniques in Abdomen and Pelvis

This article explores new acquisition methods in magnetic resonance (MR) imaging to provide high spatial and temporal resolution imaging for a wide spectrum of clinical applications in the abdomen and pelvis. We present an overview of some of these advanced MR techniques, such as non-cartesian image acquisition, fast sampling and compressed sensing, diffusion quantification and quantitative MR that can improve data sampling, enhance image quality, yield quantitative measurements, and/or optimize diagnostic performance in the body.

Assessing Liver Function in Liver Tumors Patients: The Performance of T1 Mapping and Residual Liver Volume on Gd-EOBDTPA-Enhanced MRI

Purpose: To assess the performance of T1 mapping and residual liver volume (RLV) on Gd-EOBDTPA-enhanced MRI in pretreatment estimation of liver function in patients with liver tumors. Indocyanine green retention rate at 15 min (ICG R-15) was used as a reference standard. Methods: Ethical approval from the institutional review board and informed consent were obtained for this prospective study. We enrolled 155 patients with liver tumors who underwent pretreatment Gd-EOB-DTPA-enhanced MRI. T1 relaxation time before (T1-pre), 20 min after (T1-post) Gd-EOB-DTPA injection and RLV were measured. The absolute reduction (ΔT1) and reduction rate (ΔT1%) of T1 relaxation time, volume-assisted ΔT1 (ΔT1*RLV) and volume-assisted ΔT1% (ΔT1%*RLV) were calculated accordingly. The correlation of MR parameters with ICG R-15 was determined using Spearman's rank correlation analysis. Patients were classified into the normal liver function (NLF) group if their ICG R-15 levels were <10% or otherwise into the abnormal liver function (ALF) group. Receiver operating characteristic (ROC) analysis was conducted to evaluate the performances of the MR parameters in predicting ALF. Results: T1-post (r = 0.472, P < 0.001), ΔT1 (r = -0.355, P = 0.011), ΔT1% (r = -0.482, P < 0.001), RLV (r = -0.336, P < 0.001), volume-assisted ΔT1 (r = -0.458, P < 0.001) and volume-assisted ΔT1% (r = -0.522, P < 0.001) showed weak to moderate correlation with ICG R-15. The area under the ROC curves (AUROC) of volume-assisted ΔT1 in predicting ALF was 0.777, which was significantly higher than the other parameters (P < 0.05 for all). Conclusions: Combined T1 mapping and RLV on Gd-EOB-DTPA-enhanced MRI can help assess liver function with good diagnostic accuracy in patients with liver tumors before treatment.

Gd-EOB-DTPA-enhanced MRI T1 relaxometry as an imaging-based liver function test compared with 13C-methacetin breath test

Background

Gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) can be used as an imaging-based liver function test. This study aims to further corroborate its validity.

Purpose

To compare Gd-EOB-DTPA-enhanced MRI as an imaging-based liver function test with the 13C-methacetin breath test.

Material and Methods

Fifty-three patients who underwent Gd-EOB-DTPA-enhanced MRI T1 relaxometry before and 20 min after intravenous Gd-EOB-DTPA administration as well as a 13C-methacetin breath test (LiMAx test) were retrospectively analyzed. T1 relaxation times of liver parenchyma, total liver volume (TLV), and functional liver volume (FLV) were determined. Pearson correlations, multiple linear regression analysis, and receiver operating characteristic curve analysis were performed with indices derived from T1 relaxometry, liver volumetry, and laboratory parameters to identify the best predictor of liver function as determined by the LiMAx test.

Results

T1 reduction rate (T1 RR), T1 RR × TLV, T1 RR × FLV, and T1 relaxation time 20 min after intravenous Gd-EOB administration showed a statistically significant correlation with LiMAx and discriminatory capacity between patients with LiMAx of > and < 315 µg/kg/h. Of the indices investigated, T1 RR showed the best discriminatory capacity and proved to be the only statistically significant parameter in multiple linear regression analysis.

Conclusion

Gd-EOB-DTPA-enhanced MRI as an imaging-based liver function test also correlates with the LiMAx test which in turn reflects cytochrome P450 function. The T1 reduction rate of the liver on Gd-EOB-DTPA-enhanced MRI allows prediction of liver function as determined by the LiMAx test both for 1.5 and 3.0 T.

GAN and dual-input two-compartment model-based training of a neural network for robust quantification of contrast uptake rate in gadoxetic acid-enhanced MRI

PURPOSE

Gadoxetic acid uptake rate (k₁ ) obtained from dynamic, contrast-enhanced (DCE) magnetic resonance imaging (MRI) is a promising measure of regional liver function. Clinical exams are typically poorly temporally characterized, as seen in a low temporal resolution (LTR) compared to high temporal resolution (HTR) experimental acquisitions. Meanwhile, clinical demands incentivize shortening these exams. This study develops a neural network-based approach to quantitation of k₁ , for increased robustness over current models such as the linearized single-input, two-compartment (LSITC) model.

METHODS

Thirty Liver HTR DCE MRI exams were acquired in 22 patients with at least 16 min of postcontrast data sampled at least every 13 s. A simple neural network (NN) with four hidden layers was trained on voxel-wise LTR data to predict k₁ . Low temporal resolution data were created by subsampling HTR data to contain six time points, replicating the characteristics of clinical LTR data. Both the total length and the placement of points in the training data were varied considerably to encourage robustness to variation. A generative adversarial network (GAN) was used to generate arterial and portal venous inputs for use in data augmentation based on the dual-input, two-compartment, pharmacokinetic model of gadoxetic acid in the liver. The performance of the NN was compared to direct application of LSITC on both LTR and HTR data. The error was assessed when subsampling lengths from 16 to 4 min, enabling assessment of robustness to acquisition length.

RESULTS

For acquisition lengths of 16 min NRMSE (Normalized Root-Mean-Squared Error) in k₁ was 0.60, 1.77, and 1.21, for LSITC applied to HTR data, LSITC applied to LTR data, and GAN-augmented NN applied to LTR data, respectively. As the acquisition length was shortened, errors greatly increased for LSITC approaches by several folds. For acquisitions shorter than 12 min the GAN-augmented NN approach outperformed the LSITC approach to a statistically significant extent, even with HTR data.

CONCLUSIONS

The study indicates that data length is significant for LSITC analysis as applied to DCE data for standard temporal sampling, and that machine learning methods, such as the implemented NN, have potential for much greater resilience to shortened acquisition time than directly fitting to the LSITC model.

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.

Influence of hepatic fibrosis and inflammation: Correlation between histopathological changes and Gd-EOB-DTPA-enhanced MR imaging

Objective

To evaluate the influence of an active inflammatory process in the liver on Gd-EOB-DTPA-enhanced MR imaging in patients with different degrees of fibrosis/cirrhosis.

Material and methods

Overall, a number of 91 patients (61 men and 30 women; mean age 58 years) were included in this retrospective study. The inclusion criteria for this study were Gd-EOB-DTPA-enhanced MRI of the liver and histopathological evaluation of fibrotic and inflammatory changes. T1-weighted VIBE sequences of the liver with fat suppression were evaluated to determine the relative signal change (RE) between native and hepatobiliary phase (20min). In simple and multiple linear regression analyses, the influence of liver fibrosis/cirrhosis (Ishak score) and the histopathological degree of hepatitis (Modified Hepatic Activity Index, mHAI) on RE were evaluated.

Results

RE decreased significantly with increasing liver fibrosis/cirrhosis (p < 0.001) and inflammation (mHAI, p = 0.004). In particular, a correlation between RE and periportal or periseptal boundary zone hepatitis (moth feeding necrosis, mHAI A, p = 0.001) and portal inflammation (mHAI D, p < 0.001) was observed. In multiple linear regression analysis, both the degree of inflammation and the degree of fibrosis were significant predictors for RE (p < 0.01).

Conclusion

The results of this study suggest that the MR-based hepatic enhancement index RE is not only influenced by the degree of fibrosis, but also by the degree of inflammation.

Diagnostic performance of Gd-EOB-DTPA-enhanced MRI for evaluation of liver dysfunction: a multivariable analysis of 3T MRI sequences

OBJECTIVE

The aim of this study was to evaluate the diagnostic performance of a multiparametric gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI examination for the estimation of liver dysfunction classified by the Model for End-Stage Liver Disease (MELD) score.

RESULTS

Liver dysfunction can be assessed by different methods. In a logistic regression analysis, T1- and T2-weighted images were affected by impaired liver function. In the assessment of liver dysfunction, the reduction rate in T1 mapping sequences showed a significant correlation in simple and multiple logistic regression.

CONCLUSION

Changes in Gd-EOB-DTPA-enhanced MRI between plain images and images obtained during the hepatobiliary phase allowed good prediction of liver dysfunction, especially when using T1 mapping sequences.

MATERIALS AND METHODS

A total of 199 patients underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3T. In the multivariable analysis, the full range of available MRI sequences was used to estimate the liver dysfunction of patients with various MELD scores.

Quantitative Assessment of Liver Function by Using Gadoxetic Acid-enhanced MRI: Hepatocyte Uptake Ratio

Purpose To determine whether hepatocyte uptake ratios derived at gadoxetic acid-enhanced MRI correlate with quantitative measures of liver function and can help to identify contraindication to major hepatectomy. Materials and Methods Between August 2016 and October 2016, 50 study participants with chronic liver disease or cirrhosis underwent liver MRI at 3.0 T including T1 mapping and elastography. Liver function was quantitatively assessed by using the indocyanine green retention test (ICG R₁₅). T1 maps were obtained by using the Look-Locker sequence before and 10 minutes after gadoxetic acid administration (0.025 mmol/kg). The relationship between ICG R₁₅ and the following MRI parameters was evaluated: pre- and postcontrast T1 values of the liver, hepatocyte uptake ratio representing the amount of contrast media solely taken into hepatocytes, liver volume, and degree of enhancement at the common bile duct. Diagnostic performance of the hepatocyte uptake ratio to identify patients with ICG R₁₅ greater than 20% (ie, contraindication to hepatectomy) was compared with other parameters by using areas under the receiver operating characteristic curve. Results Hepatocyte uptake ratio showed a negative correlation with ICG R₁₅ r of -0.78 (P < .001). In participants with chronic liver disease or Child-Pugh class A, those with ICG R₁₅ of 20% or less showed higher hepatocyte uptake ratio than those with ICG R₁₅ greater than 20% (P < .001). Hepatocyte uptake ratios demonstrated better performance for helping to detect ICG R₁₅ greater than 20% than did liver volume (area under the curve, 0.96 vs 0.70; P = .01). Conclusion Hepatocyte uptake ratios are negatively correlated with liver function as measured by indocyanine green retention test and provide acceptable diagnostic performance for helping to identify participants who have contraindications to major hepatectomy. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Reeder in this issue.

Evaluation of two-point Dixon water-fat separation for liver specific contrast-enhanced assessment of liver maximum capacity

Gadoxetic acid-enhanced magnetic resonance imaging has become a useful tool for quantitative evaluation of liver capacity. We report on the importance of intrahepatic fat on gadoxetic acid-supported T1 mapping for estimation of liver maximum capacity, assessed by the realtime ¹³C-methacetin breathing test (¹³C-MBT). For T1 relaxometry, we used a respective T1-weighted sequence with two-point Dixon water-fat separation and various flip angles. Both T1 maps of the in-phase component without fat separation (T1_in) and T1 maps merely based on the water component (T1_W) were generated, and respective reduction rates of the T1 relaxation time (rrT1) were evaluated. A steady considerable decline in rrT1 with progressive reduction of liver function could be observed for both T1_in and T1_W (p < 0.001). When patients were subdivided into 3 different categories of ¹³C-MBT readouts, the groups could be significantly differentiated by their rrT1_in and rrT1_W values (p < 0.005). In a simple correlation model of ¹³C-MBT values with T1_inpost (r = 0.556; p < 0.001), T1_Wpost (r = 0.557; p < 0.001), rrT1_in (r = 0.711; p < 0.001) and rrT1_W (r = 0.751; p < 0.001), a log-linear correlation has been shown. Liver maximum capacity measured with ¹³C-MBT can be determined more precisely from gadoxetic acid-supported T1 mapping when intrahepatic fat is taken into account. Here, T1_W maps are shown to be significantly superior to T1_in maps without separation of fat.

Clinical and prognostic associations of liver volume determined by computed tomography in acute liver failure

BACKGROUND

Liver volume (LV) can be non-invasively determined from the analysis of computed tomography (CT) images, and in patients with acute liver injury (ALI) or failure (ALF), it can reflect the balance of structural collapse with hepatic regeneration. We examined its relation to cause of liver injury, measures of liver function and histopathological findings, and utility in prediction of complications and mortality.

METHODS

Two hundred and seventy-three patients with ALF/ALI admitted to a specialist intensive care unit were studied. One hundred and ninety-nine patients (73%) had non-acetaminophen (NA) aetiologies and 74 (27%) had acetaminophen-induced disease. LV and proportion of predicted LV (PLV%) were determined from admission CT imaging.

RESULTS

LV and PLV% showed marked variation when aetiologic groups were compared (P < .0001), including loss in cases with indeterminate cause (LV 939 cm³ [IQR 680-1259], PLV% 56% [42-84]) and increase in Budd-Chiari syndrome (1891 cm³ [1601-2094], 121% [111-131]). Progression to high-grade encephalopathy was more common with smaller LV and PLV. A < 1000 cm³ threshold identified NA patients who later developed it with 93% (95%CI 83-98) specificity and odds ratio 10.6 (3.3-34.5) at median 5 days prior to onset, and risk of death in those with NA-drug-induced (DILI) or indeterminate disease with 91% (71-99) specificity and 63% (50-75) sensitivity.

CONCLUSION

In patients with ALF/ALI, LV shows marked variation by the cause of disease, and in prognostic importance. In indeterminate and DILI cases, loss of volume to <1000 cm³ may indicate irreversible liver injury and regenerative failure and serve as an early clinical predictor for the development of high-grade encephalopathy and death.

Prediction of Posthepatectomy Liver Failure: MRI With Hepatocyte-Specific Contrast Agent Versus Indocyanine Green Clearance Test

OBJECTIVE

The objective of our study was to identify whether quantitative measurements from gadoxetic acid-enhanced MRI are useful for predicting posthepatectomy liver failure (PHLF) in patients with hepatocellular carcinoma (HCC) compared with and in combination with future remnant liver volume (FRLV) and an indocyanine green (ICG) clearance test.

MATERIALS AND METHODS

Preoperative gadoxetic acid-enhanced MR images were retrospectively evaluated in 73 patients who underwent anatomic liver resection for HCC between 2011 and 2013. For quantitative measurement of hepatocyte function, relative liver enhancement (RLE) and remnant hepatocyte uptake index (rHUI) were measured using hepatobiliary phase MR images. FRLV was determined using measurements from preoperative CT scans. Univariate and multivariate analyses of measurements from gadoxetic acid-enhanced MRI, ICG clearance tests, and FRLV for finding predictors of PHLF were performed. To compare the diagnostic performance of predictors, ROC analyses were also performed.

RESULTS

Eighteen (25%) of 73 patients met the criteria for PHLF. Univariate analysis revealed that all measurements related to MRI including RLE, rHUI, ICG clearance, and FRLV were significantly associated with PHLF. Multivariate analysis showed that RLE, FRLV, ICG-plasma disappearance rate (ICG-PDR), rHUI, and rHUI corrected for body weight (rHUI-BW) were independent predictors of PHLF (p = 0.011, p = 0.034, p = 0.003, p < 0.001, and p = 0.001, respectively). In ROC analyses, AUCs of rHUI and rHUI-BW were larger than those of other independent predictors; the differences were statistically significant (for rHUI-BW vs RLE, ICG-PDR, and FRLV, p = 0.016, 0.007, and 0.046, respectively; for rHUI vs RLE and ICG-PDR, p = 0.045 and 0.016, respectively).

CONCLUSION

Measurements from gadoxetic acid-enhanced MRI predicted PHLF better than the ICG clearance test in patients with HCC who underwent hepatectomy.

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.

Post-hepatectomy liver failure after major hepatic surgery: not only size matters

Objectives

To compare the value of functional future liver remnant (functFLR) to established clinical and imaging variables in prediction of post-hepatectomy liver failure (PHLF) after major liver resection.

Methods

This retrospective, cross-sectional study included 62 patients, who underwent gadoxetic acid enhanced MRI and MDCT within 10 weeks prior to resection of ≥ 4 liver segments. Future liver remnant (FLR) was measured in MDCT using semi-automatic software. Relative liver enhancement for each FLR segment was calculated as the ratio of signal intensity of parenchyma before and 20 min after i.v. administration of gadoxetic acid and given as mean (remnantRLE). Established variables included indocyanine green clearance, FLR, proportion of FLR, weight-adapted FLR and remnantRLE. functFLR was calculated as FLR multiplied by remnantRLE and divided by patient’s weight. The association of measured variables and PHLF was tested with univariate and multivariate logistic regression analysis and receiver operator characteristics (ROC) curves compared with the DeLong method.

Results

Sixteen patients (25.8%) experienced PHLF. Univariate logistic regression identified FLR (p = 0.015), proportion of FLR (p = 0.004), weight-adapted FLR (p = 0.003), remnantRLE (p = 0.002) and functFLR (p = 0.002) to be significantly related to the probability of PHLF. In multivariate logistic regression analysis, a decreased functFLR was independently associated with the probability of PHLF (0.561; p = 0.002). Comparing ROC curves, functFLR showed a significantly higher area under the curve (0.904; p < 0.001) than established variables.

Conclusions

functFLR seems to be superior to established variables in prediction of PHLF after major liver resection.

Key Points

• functFLR is a parameter combining volumetric and functional imaging information, derived from MDCT and gadoxetic acid enhanced MRI.

• In comparison to other established methods, functFLR is superior in prediction of post-hepatectomy liver failure.

• functFLR could help to improve patient selection prior major hepatic surgery.

Gd-EOB-DTPA-enhanced T1 relaxometry for assessment of liver function determined by real-time 13C-methacetin breath test

OBJECTIVES

To determine whether liver function as determined by intravenous administration of ¹³C-methacetin and continuous real-time breath analysis can be estimated quantitatively from gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) relaxometry.

METHODS

Sixty-six patients underwent a ¹³C-methacetin breath test (¹³C-MBT) for evaluation of liver function and Gd-EOB-DTPA-enhanced T1-relaxometry at 3 T. A transverse 3D VIBE sequence with an inline T1 calculation based on variable flip angles was acquired prior to (T1 pre) and 20 min post-Gd-EOB-DTPA (T1 post) administration. The reduction rate of T1 relaxation time (rrT1) and T1 relaxation velocity index (∆R1) between pre- and post-contrast images was evaluated. ¹³C-MBT values were correlated with T1_post, ∆R1 and rrT1, providing an MRI-based estimated ¹³C-MBT value. The interobserver reliability was assessed by determining the intraclass correlation coefficient (ICC).

RESULTS

Stratified by three different categories of ¹³C-MBT readouts, there was a constant increase of T1 post with increasing progression of diminished liver function (p ≤ 0.030) and a constant significant decrease of ∆R1 (p ≤ 0.025) and rrT1 (p < 0.018) with progression of liver damage as assessed by ¹³C-methacetin breath analysis. ICC for all T1 relaxation values and indices was excellent (> 0.88). A simple regression model showed a log-linear correlation of ¹³C-MBT values with T1_post (r = 0.57; p < 0.001), ∆R1 (r = 0.59; p < 0.001) and rrT1 (r = 0.70; p < 0.001).

CONCLUSION

Liver function as determined using real-time ¹³C-methacetin breath analysis can be estimated quantitatively from Gd-EOB-DTPA-enhanced MR relaxometry.

KEY POINTS

• Gd-EOB-DTPA-enhanced T1 relaxometry quantifies liver function • Gd-EOB-DTPA-enhanced MR relaxometry may provide parameters for assessing liver function before surgery • Gd-EOB-DTPA-enhanced MR relaxometry may be useful for monitoring liver disease progression • Gd-EOB-DTPA-enhanced MR relaxometry has the potential to become a novel liver function index.

Comparison of 10- and 20-min hepatobiliary phase images on Gd-EOB-DTPA-enhanced MRI T1 mapping for liver function assessment in clinic

PURPOSE

To compare hepatobiliary phase (HBP) images obtained 10 and 20 min after Gd-EOB-DTPA-enhanced MRI for liver function assessment in clinic on 3.0 T MR imaging.

METHODS

103 patients were separated into four groups: 38 patients for the normal liver function (NLF) group, 33 patients for the liver cirrhosis with Child-Pugh A (LCA) group, 21 patients for the liver cirrhosis with Child-Pugh B group, and 11 patients for a liver cirrhosis with Child-Pugh C group. T1 relaxation times (T1rt) were measured on T1 mapping and reduction rates of T1rt (rrT1rt) were calculated. HBP images were obtained at the 10- and 20-min mark after Gd-EOB-DTPA enhancement.

RESULTS

T1rt on pre-enhancement imaging showed no significant difference (p > 0.05) among all four groups. T1rt for both the 10-min HBP and the 20-min HBP showed a significant difference (p < 0.05) among all groups, but showed no significant difference (p > 0.05) between the NLF group and the LCA group. T1rt and rrT1rt showed no significant difference (p > 0.05) between 10-min HBP and 20-min HBP among all groups. The ROC analysis on 10-min HBP and 20-min HBP showed a lower diagnostic performance between NLF group and LCA group (AUC from 0.532 to 0.582), but high diagnostic performance (AUC from 0.788 to 1.000) among others group.

CONCLUSIONS

In comparing 10-min HBP and 20-min HBP T1 mapping after Gd-EOB-DTPA enhancement, our results suggest that 10-min HBP T1 mapping is a feasible option for quantitatively assessing liver function.

T2* Mapping from Multi-Echo Dixon Sequence on Gadoxetic Acid-Enhanced Magnetic Resonance Imaging for the Hepatic Fat Quantification: Can It Be Used for Hepatic Function Assessment?

Objective

To evaluate the diagnostic value of T2^* mapping using 3D multi-echo Dixon gradient echo acquisition on gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) as a tool to evaluate hepatic function.

Materials and Methods

This retrospective study was approved by the IRB and the requirement of informed consent was waived. 242 patients who underwent liver MRIs, including 3D multi-echo Dixon fast gradient-recalled echo (GRE) sequence at 3T, before and after administration of gadoxetic acid, were included. Based on clinico-laboratory manifestation, the patients were classified as having normal liver function (NLF, n = 50), mild liver damage (MLD, n = 143), or severe liver damage (SLD, n = 30). The 3D multi-echo Dixon GRE sequence was obtained before, and 10 minutes after, gadoxetic acid administration. Pre- and post-contrast T2^* values, as well as T2^* reduction rates, were measured from T2^* maps, and compared among the three groups.

Results

There was a significant difference in T2^* reduction rates between the NLF and SLD groups (−0.2 ± 4.9% vs. 5.0 ± 6.9%, p = 0.002), and between the MLD and SLD groups (3.2 ± 6.0% vs. 5.0 ± 6.9%, p = 0.003). However, there was no significant difference in both the pre- and post-contrast T2^* values among different liver function groups (p = 0.735 and 0.131, respectively). A receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve for using T2^* reduction rates to differentiate the SLD group from the NLF group was 0.74 (95% confidence interval: 0.63–0.83).

Conclusion

Incorporation of T2^* mapping using 3D multi-echo Dixon GRE sequence in gadoxetic acid-enhanced liver MRI protocol may provide supplemental information for liver function deterioration in patients with SLD.

Measuring hepatic functional reserve using T1 mapping of Gd-EOB-DTPA enhanced 3T MR imaging: A preliminary study comparing with 99mTc GSA scintigraphy and signal intensity based parameters

PURPOSE

To determine the utility of liver T1-mapping on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance (MR) imaging for the measurement of liver functional reserve compared with the signal intensity (SI) based parameters, technetium-99m-galactosyl serum albumin (^99mTc-GSA) scintigraphy and indocyanine green (ICG) clearance.

MATERIALS AND METHODS

This retrospective study included 111 patients (Child-Pugh-A 90; -B 21) performed with both Gd-EOB-DTPA enhanced liver MR imaging and ^99mTc-GSA (76 patients with ICG). Receiver operating characteristic (ROC) curve analysis was performed to compare diagnostic performances of T1-relaxation-time parameters [pre-(T1pre) and post-contrast (T1hb) Gd-EOB-DTPA], SI based parameters [relative enhancement (RE), liver-to-muscle-ratio (LMR), liver-to-spleen-ratio (LSR)] and ^99mTc-GSA scintigraphy blood clearance index (HH15)] for Child-Pugh classification. Pearson's correlation was used for comparisons among T1-relaxation-time parameters, SI-based parameters, HH15 and ICG.

RESULTS

A significant difference was obtained for Child-Pugh classification with T1hb, ΔT1, all SI based parameters and HH15. T1hb had the highest AUC followed by RE, LMR, LSR, ΔT1, HH15 and T1pre. The correlation coefficients with HH15 were T1pre 0.22, T1hb 0.53, ΔT1 -0.38 of T1 relaxation parameters; RE -0.44, LMR -0.45, LSR -0.43 of SI-based parameters. T1hb was highest for correlation with HH15. The correlation coefficients with ICG were T1pre 0.29, T1hb 0.64, ΔT1 -0.42 of T1 relaxation parameters; RE -0.50, LMR -0.61, LSR -0.58 of SI-based parameters; 0.64 of HH15. Both T1hb and HH15 were highest for correlation with ICG.

CONCLUSION

T1 relaxation time at post-contrast of Gd-EOB-DTPA (T1hb) was strongly correlated with ICG clearance and moderately correlated HH15 with ^99mTc-GSA. T1hb has the potential to provide robust parameter of liver functional reserve.

Gd-EOB-DTPA-enhanced MRI for evaluation of liver function: Comparison between signal-intensity-based indices and T1 relaxometry

Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a paramagnetic hepatobiliary magnetic resonance (MR) contrast agent. Due to its OATP1B1/B3-dependent hepatocyte-specific uptake and paramagnetic properties increasing evidence has emerged to suggest that Gd-EOB-DTPA-enhanced MRI can be potentially used for evaluation of liver function. In this paper we compare the diagnostic performance of Gd-EOB-DTPA-enhanced relaxometry-based and commonly used signal-intensity (SI)-based indices, including the hepatocellular uptake index (HUI) and SI-based indices corrected by spleen or muscle, for evaluation of liver function, determined using the Indocyanin green clearance (ICG) test. Simple linear regression model showed a significant correlation of the plasma disappearance rate of ICG (ICG-PDR) with all Gd-EOB-DTPA-enhanced MRI-based liver function indices with a significantly better correlation of relaxometry-based indices on ICG-PDR compared to SI-based indices. Among SI-based indices, HUI achieved best correlation on ICG-PDR and no significant difference of respective correlations on ICG-PDR could be shown. Assessment of liver volume and consecutive evaluation of multiple linear regression model revealed a stronger correlation of ICG-PDR with both (SI)-based and T1 relaxometry-based indices. Thus, liver function can be estimated quantitatively from Gd-EOB-DTPA-enhanced MRI-based indices. Here, indices derived from T1 relaxometry are superior to SI-based indices, and all indices benefit from taking into account respective liver volumes.

Potential use of metabolic breath tests to assess liver disease and prognosis: has the time arrived for routine use in the clinic?

The progression of liver disease may be unique among organ system diseases in that progressive fibrosis compromises not only the sufficiency of hepatocyte mass but also impairs blood flow to the liver, resulting in porto-systemic shunting. Although liver biopsy as an assessment of fibrosis has become the key biomarker of and target for new therapies, it is invasive and subject to sampling error, and cannot quantify metabolic function or porto-systemic shunting. Measurement of the hepatic venous pressure gradient accommodates some of the deficiencies of biopsy but requires expertise not widely available and misses minor changes in hepatocellular mass and thereby information about metabolic function. Thus, an unmet need in clinical hepatology remains unfulfilled: a noninvasive biomarker which quantitates both the hepatocellular insufficiency and porto-systemic shunting inherent in progressive hepatic fibrosis. Ideally, such a biomarker should correlate with clinical endpoints including liver-related survival and cirrhotic complications, be performed at the point-of-care, and be affordable and easy to use. This review, an expert opinion, summarizes background and recent data suggesting that metabolic breath tests may now meet these requirements and have a valid place in clinical hepatology to supplant the time-honoured assessment of hepatic fibrosis.

Evaluating segmental liver function using T1 mapping on Gd-EOB-DTPA-enhanced MRI with a 3.0 Tesla

Background

Assessing the liver function provides valuable information to evaluate surgical risk and plan accordingly. Current studies focus on whole liver function evaluation. However, assessment of segmental liver function is equally important in the clinical practice. The purpose of this study was to investigate whether Gd-EOB-DTPA-enhanced MRI can evaluate the liver function of each segment by using T1 mapping at 3 Tesla MRI.

Methods

One hundred three patients were classified into one of 4 groups: a normal liver function (NLF) group (n = 38), a liver cirrhosis with Child-Pugh A (LCA) group (n = 33), a liver cirrhosis with Child-Pugh B (LCB) group (n = 21), and a liver cirrhosis with Child-Pugh C (LCC) group (n = 11). All patients underwent Gd-EOB-DTPA-enhanced MRI scans. T1 relaxation times were measured on the liver superimposing T1 mapping images. Reduction rate (△%) of T1 relaxation time of the liver parenchyma were calculated.

Results

After 20 min of Gd-EOB-DTPA enhancement, the T1 relaxation time of all liver segments in the LCC group were different from those in all the other groups, and more liver segments from the LCB and LCA groups different from the NLF group (p < 0.05). For the LCB group, the areas under the receiver operating characteristic curves (AUCs) of different liver segments for hepatobiliary phase (HBP) were 0.654-0.904 on T1 relaxation time, and 0.709-0.905 on △%. For the LCC group, the AUCs of different liver segments for HBP were 0.842–0.997 on T1 relaxation time, and 0.887–0.990 on △%.

Conclusions

For LCB patients, segmental liver function evaluation is possible using Gd-EOB-DTPA-enhanced MRI T1 mapping. For LCC patients, all liver segments can be used to evaluate liver function and both T1 relaxation time and the △% of T1 relaxation time have good diagnostic performance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12880-017-0192-x) contains supplementary material, which is available to authorized users.

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.