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

Functional Liver Imaging Score (FLIS) as imaging parameter for predicting post-hepatectomy complications in patients with liver cirrhosis

BackgroundLiver dysfunction has been reported as a risk factor for predicting complications after hepatectomy. In patients with liver cirrhosis (LC) who underwent hepatectomy, a Functional Liver Imaging Score (FLIS), derived from gadoxetic acid-enhanced magnetic resonance imaging (MRI), has never been investigated as a predictor of clinically significant post-hepatectomy complications.PurposeTo evaluate whether FLIS can predict post-hepatectomy complications in patients with LC.Material and MethodsA retrospective review was conducted of patients with LC who underwent gadoxetic acid-enhanced MRI and hepatectomy. Univariable and multivariable logistic regression was used to identify clinicopathological and radiologic findings associated with the development of major complication (Clavien-Dindo classification [CDC] ≥ III). Receiver operating characteristic (ROC) curve analysis was performed to determine the cutoff value of FLIS for predicting CDC ≥ III.ResultsOf the finally included 106 patients (77 men; mean age = 62.5 ± 8.3 years), 12 patients had a CDC ≥ III. Multivariable analysis showed that only FLIS independently predicted post-hepatectomy complications (odds ratio = 0.02; P = 0.01). ROC analysis suggested the FLIS ≤ 4 was the optimal cutoff for predicting CDC ≥ III (AUC value = 0.94; sensitivity = 91.67%; specificity = 95.74%; positive likelihood ratio = 21.54; and negative likelihood ratio = 0.09).ConclusionIn patients with LC, FLIS was an independent predictor of post-hepatectomy complications. FLIS showed excellent diagnostic performance in predicting post-hepatectomy complications.

Preoperative assessment of liver regeneration using T1 mapping and the functional liver imaging score derived from Gd-EOB-DTPA-enhanced magnetic resonance for patient with hepatocellular carcinoma after hepatectomy

Objectives

To explore whether T1 mapping parameters and the functional liver imaging score (FLIS) based on Gd-EOB-DTPA MRI could evaluate liver regeneration after hepatectomy for HCC patient.

Methods

This retrospective study finally included 60 HCC patients (48 men and 12 women, with a median age of 53 years). T1 relaxation time of liver before gadoxetic acid injection (T1pre) and during the hepatobiliary phase (T1HBP), reduction rate (Δ%) and FLIS were calculated, their correlations with liver fibrosis stage, hepatic steatosis, and liver regeneration, quantified as regeneration index (RI), were assessed by Kendall's tau-b correlation test or Spearman's correlation test. Multivariate linear regression analyses were used to explore the indicator of RI.

Results

T1pre, T1HBP, Δ%, and FLIS manifested significant correlation with fibrosis stage (r = 0.434, P =0.001; r = 0.546, P < 0.001; r = -0.356, P =0.005; r = -0.653, P <0.001, respectively). T1pre showed significant correction with steatosis grade (r = 0.415, P =0.001). Fibrosis stage and steatosis grade were associated with RI (r = -0.436, P<0.001; r = -0.338, P =0.008). Accordingly, T1pre, T1HBP and FLIS were the significant predictors (P<0.05) of RI in multivariate analysis. Similarly, in the patients undergoing minor hepatectomy (n=35), T1HBP, Δ% and FLIS were related to RI (P<0.05) in multivariate analysis. Nevertheless, in the patients undergoing major hepatectomy (n=25), no T1 mapping parameter and FLIS was the independent predictor of RI.

Conclusions

T1 mapping parameters and FLIS were the potential noninvasive indicators of liver regeneration, except for HCC patients undergoing major hepatectomy.

Clinical relevance statement

The value of T1 mapping and FLIS with Gd-EOB-DTPA MRI for accurate preoperative evaluation of liver regeneration is critical to prevent liver failure and improve prognosis of HCC patients.

Low functional liver imaging score is associated with poor prognosis following hepatectomy for hepatocellular carcinoma

Liver function affects the prognosis of patients with hepatocellular carcinoma (HCC). This study aimed to investigate the prognostic impact of the functional liver imaging score (FLIS), assessed using gadoxetic acid-enhanced magnetic resonance imaging, on long-term outcomes following hepatectomy for HCC. The FLIS was assessed in 235 patients who underwent initial hepatectomy for HCC. The relationship between FLIS and prognosis was retrospectively analyzed. The FLIS was 6 in 185, and 2-5 in 50, patients. The 5-year recurrence-free and overall survival rates were 43.6% and 76.4% in patients with an FLIS of 6, and 23.0% and 42.4% in patients with an FLIS of 2-5, respectively; both recurrence-free and overall survival were significantly better in patients with an FLIS of 6 (P = 0.012 and 0.001, respectively). Multivariable analyses revealed that microvascular invasion (hazard ratio: 3.611; P = 0.002) and an FLIS of 2-5 (hazard ratio: 2.558; P = 0.027) were independently associated with shorter overall survival. After propensity-score matching, overall survival was significantly better in patients with an FLIS of 6. A low FLIS was significantly associated with poor prognosis following initial hepatectomy for HCC, suggesting that surgical indications must be carefully considered in patients with a low FLIS.

Non-invasive imaging biomarkers in chronic liver disease

Chronic liver disease (CLD) is a global and worldwide clinical challenge, considering that different underlying liver entities can lead to hepatic dysfunction. In the past, blood tests and clinical evaluation were the main noninvasive tools used to detect, diagnose and follow-up patients with CLD; in case of clinical suspicion of CLD or unclear diagnosis, liver biopsy has been considered as the reference standard to rule out different chronic liver conditions. Nowadays, noninvasive tests have gained a central role in the clinical pathway. Particularly, liver stiffness measurement (LSM) and cross-sectional imaging techniques can provide transversal information to clinicians, helping them to correctly manage, treat and follow patients during time. Cross-sectional imaging techniques, namely computed tomography (CT) and magnetic resonance imaging (MRI), have plenty of potential. Both techniques allow to compute the liver surface nodularity (LSN), associated with CLDs and risk of decompensation. MRI can also help quantify fatty liver infiltration, mainly with the proton density fat fraction (PDFF) sequences, and detect and quantify fibrosis, especially thanks to elastography (MRE). Advanced techniques, such as intravoxel incoherent motion (IVIM), T1- and T2- mapping are promising tools for detecting fibrosis deposition. Furthermore, the injection of hepatobiliary contrast agents has gained an important role not only in liver lesion characterization but also in assessing liver function, especially in CLDs. Finally, the broad development of radiomics signatures, applied to CT and MR, can be considered the next future approach to CLDs. The aim of this review is to provide a comprehensive overview of the current advancements and applications of both invasive and noninvasive imaging techniques in the evaluation and management of CLD.

Validation of functional liver imaging scores derived on gadoxetic acid-enhanced MRI in hepatocellular carcinoma patients

Background and Aim

To investigate the correlation of the functional liver imaging scores (FLIS) and the scoring system in hepatocellular carcinoma (HCC) patients.

Materials and Methods

Between April 2015 and December 2022, the HCC patients who underwent gadoxetic acid-enhanced MRI were analyzed. Three parameters on hepatobiliary phase images were evaluated for FLIS: liver parenchymal enhancement, biliary excretion, and signal intensity of the portal vein. The correlation between Child-Turcotte-Pugh (CTP) classification, the albumin-bilirubin (ALBI) grade, and Fibrosis-4 (F-4) score, and FLIS were analyzed. Receiver operating characteristic curve analysis was performed to demonstrate the cut-off value of FLIS for differentiating between CTP classification and ALBI grade.

Results

We retrospectively analyzed 178 HCC patients (144 men, 34 women; mean age, 65.9 years). A moderate negative correlation was present between CTP classification and ALBI grade, and FLIS (r=-0.596 and r=-0.513, respectively). FLIS ≤3 was determined as the most optimal criterion for differentiating CTP A or B patients from CTP C patients.

Conclusion

This study showed that the FLIS is a simple, non-invasive imaging marker for the assessment of liver function in HCC patients.

Functional Liver Imaging Score Derived from Gadoxetic Acid-enhanced MRI Predicts Cachexia and Prognosis in Hepatocellular Carcinoma Patients

OBJECTIVE

Cachexia occurs in approximately half of hepatocellular carcinoma (HCC) patients as the disease progresses and is correlated with a poor prognosis. Therefore, early identification of HCC patients at risk of developing cachexia and their prognosis is crucial. This study investigated the functional liver imaging score (FLIS) derived from gadoxetic acid-enhanced magnetic resonance imaging (MRI) to identify cachexia in HCC patients and their prognosis.

METHODS

Pretreatment clinical and MRI data from 339 HCC patients who underwent gadoxetic acid-enhanced MRI scans were retrospectively collected. Patient weights were recorded for 6 months following the MRI scan to diagnose cachexia. The FLIS was calculated as the sum of the enhancement quality score, the excretion quality score, and the portal vein sign quality score. A Cox proportional hazards model was used to determine the significant factors affecting overall survival (OS). Multivariable logistic regression was then conducted to identify variables predicting cachexia in HCC patients, which were subsequently used to predict OS.

RESULTS

Cox regression analysis revealed a significant association between cachexia and worse OS. Both FLIS (0-4 vs. 5-6 points) (OR, 9.20; 95% CI: 4.68-18.10; P<0.001) and α-fetoprotein >100 ng/mL (OR, 4.08; 95% CI: 2.13-7.83; P<0.001) emerged as significant predictors of cachexia in patients with HCC. Furthermore, FLIS (0-4 vs. 5-6 points) (HR, 1.73; 95% CI: 1.19-2.51; P=0.004) was significantly associated with OS. Patients in the FLIS 0-4 points group had shorter OS than those in the FLIS 5-6 points group [20 months (95% CI, 14.7-25.3) vs. 43 months (95% CI, 27.7-58.3); P=0.001].

CONCLUSION

Cachexia was associated with worse OS. The functional liver imaging score emerged as a significant predictor of cachexia in HCC patients and their prognosis.

Noninvasive diagnosis of liver cirrhosis: qualitative and quantitative imaging biomarkers

A diagnosis of cirrhosis initiates a shift in the management of chronic liver disease and affects the diagnostic workflow and treatment decision of primary liver cancer. Liver biopsy remains the gold standard for cirrhosis diagnosis, but it is invasive and susceptible to sampling bias and observer variability. Various qualitative and quantitative imaging biomarkers based on ultrasound, CT and MRI have been proposed for noninvasive diagnosis of cirrhosis. Qualitative imaging features are easy to apply but have moderate diagnostic sensitivity. Elastography techniques allow quantitative assessment of liver stiffness and are highly accurate for cirrhosis diagnosis. Ultrasound elastography are widely used in clinical practice, while MR elastography has narrower availability. Although not applicable in clinical practice yet, other quantitative imaging features, including liver surface nodularity, linear and volumetric measurement, extracellular volume fraction, liver enhancement on hepatobiliary phase, and parameters derived from diffusion-weighted imaging, can provide additional information of liver morphology, perfusion, and function, thus may increase diagnosis performance. The introduction of radiomics and deep learning has further improved diagnostic accuracy while reducing subjectivity. Several imaging features may also help to assess liver function and outcomes in patients with cirrhosis. In this review, we summarize the qualitative and quantitative imaging biomarkers for noninvasive cirrhosis diagnosis, and the assessment of liver function and outcomes, and discuss the challenges and future directions in this field.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Technical Note: Novel imaging method to obtain gray matter-attenuated inversion recovery image using low-field magnetic resonance imaging systems

INTRODUCTION

The double inversion recovery (DIR) technique suppresses two types of tissue signals with different T1 values by applying two inversion recovery (IR) pulses with different inversion times (TI). In contrast, the double tissue suppression with multi-echo acquisition and single TI combining HIRE (DOMUST-HIRE) method, is a technique enabling the white-matter-attenuated inversion recovery (WAIR) images by setting one inversion time (TI) in a sequence based on the multi-echo method and subtracting the second echo image from the first echo image. Here, we propose a new sequence that can provide the gray-matter-attenuated inversion recovery image based on the DOMUST-HIRE method.

METHODS

In this small clinical study, we performed determination of optimal TI and physical evaluation by imaging a subject's head with T1WI and our proposed method for GAIR images.

RESULTS

Our proposed method could increase the contrast ratio and the contrast-to-noise ratio between white matter (WM) and gray matter (GM), whereas the signal-to-noise ratio WM and GM decreased than with T1WI method.

CONCLUSIONS

Our proposed method can be used to suppress GM and CSF signals.

IMPLICATIONS FOR PRACTICE

The use of our proposed method in low-field MRI systems could provide GAIR image.

Inter-reader reliability of functional liver imaging score derived from gadoxetic acid-enhanced MRI: a meta-analysis

PURPOSE

This study aimed to systematically determine the inter-reader reliability of the functional liver imaging score (FLIS) and explore the factors affecting it.

METHODS

Original articles reporting the inter-reader reliability of FLIS derived from gadoxetic acid-enhanced magnetic resonance imaging (MRI) were systematically searched in the MEDLINE and EMBASE databases from January 2013 to June 2022. Data synthesis was performed to calculate the meta-analytic pooled estimates of the FLIS and its three subcategories, including enhancement quality score (EnQS), excretion quality score (ExQS), and portal vein sign quality score (PVsQS) using the DerSimonian-Laird random-effects model. To explore any cause of study heterogeneity, we conducted a meta-regression analysis.

RESULTS

Six studies with data from 1419 patients were included. The meta-analytic pooled inter-reader reliability of FLIS was 0.93 (95% confidence interval [CI], 0.88-0.98). That of the three FLIS subcategories were 0.93 (95% CI, 0.85-1.00), 0.95 (95% CI, 0.91-1.00), and 0.90 (95% CI, 0.81-0.99) for EnQS, ExQS, and PVsQS, respectively. The pooled FLIS data was moderately heterogenous, but heterogeneity was not associated with the study methodology, MRI-related factors, and reader experience.

CONCLUSION

The FLIS and its three subcategories showed almost perfect inter-reader reliability. Therefore, FLIS may be a reliable imaging parameter that reflects liver function and outcomes in patients with chronic liver disease. Further studies should be conducted to confirm any factors affecting the inter-reader reliability of FLIS.

Effect of type 2 diabetes on liver images of GD-EOB-DTPA-enhanced MRI during the hepatobiliary phase

To analyze alterations of the liver appearance during the hepatobiliary phase of individuals with type 2 diabetes who are receiving gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance imaging (MRI). Fifty-seven individuals who received Gd-EOB-DTPA-enhanced MRI and had normal liver and renal function but did not have (control group) or have type 2 diabetes (observation group) were retrospectively included in this study. The liver enhancement ratio (LER) and contrast between liver parenchyma and portal vein (LPC) were calculated from hepatobiliary phase images. Utilizing liver to kidney signal intensity, signs of the biliary system, and signs of the portal vein, a functional liver imaging score (FLIS) was calculated. Wilcoxon rank-sum test was used to assess the between-group differences in LER, LPC, and FLIS. FLIS constituent ratios between the two groups were tested using the χ² test. The effectiveness of LER, LPC, and FLIS for identifying type 2 diabetes was assessed by receiver operating characteristic curves (ROCs). The interobserver consistency of FLIS was evaluated using the intraclass correlation coefficients. The observation group's LER and LPC were lower than the control group. The constituent ratio of the FLIS score (liver to kidney signal intensity, p = 0.011) showed a significant between-group difference. According to ROCs, LER and LPC were associated with the identification of type 2 diabetes. LER = 0.54 and LPC = 1.46 were the optimal cutoff for identifying type 2 diabetes, respectively. FLIS demonstrated excellent inter-reader agreement. The relative signal intensity of the liver during the hepatobiliary phase is decreased in patients with type 2 diabetes. This should be considered when individuals with type 2 diabetes undergo Gd-EOB-DTPA-enhanced MRI to avoid misdiagnoses, such as small hepatocellular carcinoma or abnormal liver function.

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

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