Evaluation of liver function using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging based on a three-dimensional volumetric analysis system

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.

Evaluation of liver function using hepatocyte uptake and T1 mapping indices in gadoxetic acid-enhanced magnetic resonance imaging: correlation with the albumin-bilirubin grading system

Background

Assessing liver function is crucial for managing chronic liver diseases. This study aimed to evaluate the efficacy of hepatocyte uptake and the longitudinal relaxation time (T1) mapping indices from gadoxetic acid-enhanced magnetic resonance imaging (MRI) for evaluating liver function and its correlation with the albumin-bilirubin (ALBI) grading system.

Methods

We retrospectively studied 183 patients who were grouped based on ALBI score: normal liver function (NLF), ALBI 1, ALBI 2, and ALBI 3. We calculated T1 indices and analyzed their correlation with ALBI grade, and differences among ALBI groups were evaluated. Receiver operating characteristic curves were used to assess the discriminative power of hepatocyte uptake and T1 indices for liver function groups, with significance set at P<0.05.

Results

Significant differences were observed in hepatocyte uptake and T1 indices across the NLF and ALBI groups (P<0.001). T1 value before enhancement (T1pre), T1 value after enhancement (T1post) prolonged, and rate of decrease in the T1 relaxation time (ΔT1), hepatocyte uptake rate (Khep) decreased with the advancement of liver function impairment, except for T1pre shortened in ALBI 3 grade. T1post (rho =0.762, P<0.001), Khep (rho =-0.759, P<0.001) and ΔT1 (rho =-0.673, P<0.01) showed strong correlations with ALBI grades. T1post and Khep were superior to T1pre and ΔT1 across all liver function groups not only in pairwise comparison but also in stratified analysis.

Conclusions

Khep and T1post provide good diagnostic performance in distinguishing ALBI groups. T1post exhibits the highest area under the curve (AUC) when predicting lower liver function groups, whereas Khep excels in predicting high-grade liver function. Gadoxetic acid-enhanced MRI with T1 mapping shows potential as a tool for assessing liver function.

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.

A Novel Method of Calculating the Drained Liver Volume Using a 3D Volume Analyzer for Biliary Drainage of Unresectable Malignant Hilar Biliary Obstruction

OBJECTIVES

In patients with unresectable malignant hilar biliary obstruction (UMHBO), drainage of ≥ 50% liver volume correlates with better clinical outcomes. Accurately measuring the liver volume to be drained by biliary stents is required. We aimed to develop a novel method for calculating the drained liver volume (DLV) using a 3D volume analyzer (3D volumetry), and assess the usefulness for drainage in patients with UMHBO.

METHODS

Three-dimensional volumetry comprises the following steps: (1) manual tracing of bile duct using 3D imaging system; (2) 3D reconstruction of bile duct and liver parenchyma; and (3) calculating DLV according to the 3D distribution of bile ducts. Using 3D volumetry, we reviewed data of patients who underwent biliary drainage for UMHBO, calculated the DLV, and determined the association between DLV and biliary drainage outcome.

RESULTS

There were 104 eligible cases. The mean DLV was 708 ± 393 ml (53% ± 21%). and 65 patients (63%) underwent drainage of   ≥50% liver volume. The clinical success rate was significantly higher in patients with DLV ≥ 50% than in patients with DLV < 50% (89% vs. 28%, P < 0.001). The median time to recurrence of biliary obstruction (TRBO) and survival time were significantly longer in patients with DLV ≥ 50% than in patients with DLV < 50% (TRBO, 292 vs. 119 days, P = 0.03; survival, 285 vs. 65days, P = 0.004, log-rank test, respectively).

CONCLUSIONS

Three-dimensional volumetry, a novel method to calculate DLV accurately according to bile duct distribution was useful for drainage in UMHBO patients.

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.

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.

Liver functional assessment using time-associated change in the liver-to-spleen signal intensity ratio on enhanced magnetic resonance imaging: a retrospective study

BACKGROUND

Liver-to-spleen signal intensity ratio (LSR) is evaluated by magnetic resonance imaging (MRI) in the hepatobiliary phase and has been reported as a useful radiological assessment of regional liver function. However, LSR is a passive (non-time-associated) assessment of liver function, not a dynamic (time-associated) assessment. Moreover, LSR shows limitations such as a dose bias of contrast medium and a timing bias of imaging. Previous studies have reported the advantages of time-associated liver functional assessment as a precise assessment of liver function. For instance, the indocyanine green (ICG) disappearance rate, which is calculated from serum ICG concentrations at multiple time points, reflects a precise preoperative liver function for predicting post-hepatectomy liver failure without the dose bias of ICG or the timing bias of blood sampling. The aim of this study was to develop a novel time-associated radiological liver functional assessment and verify its correlation with traditional liver functional parameters.

METHODS

A total of 279 pancreatic cancer patients were evaluated to clarify fundamental time-associated changes to LSR in normal liver. We defined the time-associated radiological assessment of liver function, calculated using information on LSR from four time points, as the "LSR increasing rate" (LSRi). We then investigated correlations between LSRi and previous liver functional parameters. Furthermore, we evaluated how timing bias and protocol bias affect LSRi.

RESULTS

Significant correlations were observed between LSRi and previous liver functional parameters such as total bilirubin, Child-Pugh grade, and albumin-bilirubin grade (P < 0.001 each). Moreover, considerably high correlations were observed between LSRi calculated using four time points and that calculated using three time points (r > 0.973 each), indicating that the timing bias of imaging was minimal.

CONCLUSIONS

This study propose a novel time-associated radiological assessment, and revealed that the LSRi correlated significantly with traditional liver functional parameters. Changes in LSR over time may provide a superior preoperative assessment of regional liver function that is better for predicting post-hepatectomy liver failure than LSR using the hepatobiliary phase alone.

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.

Improving accuracy, reliability, and efficiency of the RENAL nephrometry score with 3D reconstructed virtual imaging

OBJECTIVE

To clarify the diagnostic performance of the three-dimensional reconstructed virtual image (3D-RVI) in evaluating RENAL nephrometry score (RENAL-NS).

METHODS

This study included 130 patients who underwent preoperative contrast-enhanced computed tomography (CECT) followed by partial nephrectomy for renal tumors suggestive of renal cell carcinoma. RENAL-NS was calculated prior to the surgery, and tumor resection was performed referring to the score. We retrospectively reviewed preoperative CECT images. We calculated the inter-observer variability of RENAL-NS using 3D-RVI versus two-dimensional (2D) imaging and compared the ability of RENAL-NS using 3D-RVI versus 2D imaging to predict the risk of opening of the urinary collecting system. We also compared the two modalities for the time required to evaluate RENAL-NS.

RESULTS

RENAL-NS evaluated using 3D-RVI showed a higher inter-observer agreement compared to 2D-imaging (r_s = 0.85 vs. r_s = 0.65). The "nearness to sinus" score was more strongly associated with the opening of the urinary collecting system when evaluated using 3D-RVI than 2D-imaging (AUC = 0.71 vs AUC = 0.57, p = 0.016). RENAL-NS using 2D-imaging required a significantly longer time compared to 3D-RVI (p = 0.036).

CONCLUSIONS

Using 3D-RVI improves the accuracy, reliability and efficiency of RENAL-NS evaluation in preoperative assessment and can play an important role in preoperative assessment and intraoperative navigation.

The Assessment of Regional Liver Function Before Major Hepatectomy Using Magnetic Resonance Imaging

BACKGROUND

The liver-to-spleen signal intensity ratio (LSR) on magnetic resonance imaging with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid has been used as a parameter to assess liver function. LSR of the future remnant liver region (FR-LSR) is included in preoperative assessment of regional liver function. The aim of this study was to investigate the predictability of post-hepatectomy liver failure (PHLF) by FR-LSR.

METHODS

Between May 2013 and May 2019, 127 patients underwent standardized EOB-MRI for diagnosis of liver tumor before major hepatectomy. The FR-LSR on EOB-MRI was calculated by a semiautomated three-dimensional volumetric analysis system. The cutoff value of FR-LSR in association with clinically relevant PHLF was determined according to the areas under the receiver operating characteristic curves. Then, FR-LSR and clinical variables were analyzed to assess the risk of clinically relevant PHLF.

RESULTS

In patients with preoperative biliary drainage, metastatic liver tumor, estimated future remnant liver volume <50%, biliary reconstruction, operation time ≥ 480 min, estimated blood loss ≥ 1000 g, blood transfusion and a FR-LSR < 2.00 were associated with clinically relevant PHLF (P < .05 for all) in univariable analysis. The liver-to-spleen signal intensity ratio of the future remnant liver region < 2.00 was the only independent risk factor for clinically relevant PHLF in multivariable risk analysis (OR, 27.90; 95% CI: 7.99-136.40; P < .05).

DISCUSSION

The present study revealed that FR-LSR calculated using a 3-dimensional volumetric analysis system was an independent risk factor for clinically relevant PHLF. The liver-to-spleen signal intensity ratio of the future remnant liver region might be a reliable preoperative parameter in liver functional assessment, enabling safe performance of major hepatectomy.

Impact of previous history of choledochojejunostomy on the incidence of organ/space surgical site infection after hepatectomy

PURPOSE

Impact of previous history of choledochojejunostomy (PCJ) on the incidence of organ/space surgical site infection (SSI) after hepatectomy remains unclear. The aim of this study was to investigate the incidence and causes of SSI after hepatectomy.

METHODS

Patients who underwent hepatectomy of ≤1 Couinaud's sector between January 2011 and September 2019 were retrospectively analyzed. Incidence of and risk factors for organ/space SSI (Clavien-Dindo grade ≥2) after hepatectomy were investigated.

RESULTS

Among 750 hepatectomies, 18 patients (2.4%) had a medical history of PCJ. Incidence of organ/space SSI was higher in patients with PCJ (50%) than in those without PCJ (3%, P < 0.001), and the trend was consistent even after estimated propensity score matched cohort. Multivariate analysis showed PCJ was a strong risk factor for organ/space SSI (grade ≥2), with the highest odds ratios (OR) among all other clinicopathological risk factors (OR, 32.25; P < 0.001). Among hepatectomies with PCJ, pneumobilia (OR, 12.25; P = 0.015), operation time ≥171 min (OR, 12.25; P = 0.016), and liver steatosis (OR, 24.00; P ≤ 0.005) were associated with organ/space SSI after hepatectomy.

CONCLUSION

Previous history of choledochojejunostomy was a strong risk factor for organ/space SSI after hepatectomy. The high rate of organ/space SSI after hepatectomy with PCJ might be attributed to intrahepatic bile duct contamination, increased operation time, and histological liver steatosis.

Regional liver function analysis with gadoxetic acid-enhanced MRI and virtual hepatectomy: prediction of postoperative short-term outcomes for HCC

OBJECTIVES

To explore the role of quantitative regional liver function assessed by preoperative gadoxetic acid-enhanced MRI with computer-aided virtual hepatectomy to predict short-term outcomes after major hepatectomy for HCC.

METHODS

We retrospectively reviewed the records of 133 consecutive patients with HCC who underwent preoperative gadoxetic acid-enhanced MRI and indocyanine green (ICG) test. Forty-five patients received open major hepatectomy. Liver function reserve and the future liver remnant were evaluated by computer-aided virtual hepatectomy. Global liver functional parameters included the T1 relaxation time reduction rate (T1_ratio) and functional liver volume (FV), whereas regional parameters included the rT1_pos, rT1_ratio, remnant FV (rFV), and remnant FV ratio (rFV_ratio) of the remnant liver. The functional parameters of the MRI and ICG were used to predict the short-term outcomes (liver failure and major complications) after major hepatectomy.

RESULTS

The T1_ratio and FV were correlated with the ICG test (rho = - 0.304 and - 0.449, p < 0.05). FV < 682.8 ml indicated preoperative ICG-_R15 ≥ 14% with 0.765 value of the area under the curve (AUC). No patient who underwent major resection with good liver functional reserve (ICG < 14%) and enough future remnant volume (> 30% standard LV) developed liver failure. Low rT1_ratio (< 66.5%) and high rT1_pos (> 217.5 ms) may predict major complications (AUC = 0.831 and 0.756, respectively; p < 0.05). The rT1_ratio was an independent risk factor for postoperative major complications (odds ratio [OR] = 0.845, 95% CI, 0.736-0.966; p < 0.05).

CONCLUSION

Preoperative gadoxetic acid-enhanced MRI with computer-aided virtual hepatectomy may facilitate optimal assessment of regional liver functional reserve to predict short-term outcomes after major hepatectomy for HCC.

KEY POINTS

• Preoperative gadoxetic acid-enhanced MRI with virtual hepatectomy and volumetric analysis can provide precise liver volume and regional functional assessment. • Quantitative regional liver function assessed by gadoxetic acid-enhanced MRI can predict the short-term outcomes after major hepatectomy in patients with HCC. • The regional liver function assessed by gadoxetic acid-enhanced MRI is an independent risk factor for postoperative major complications.

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.

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.