Consensus report from the 9th International Forum for Liver Magnetic Resonance Imaging: applications of gadoxetic acid-enhanced imaging

MRI Radiomics Combined with Clinicopathological Factors for Predicting 3-Year Overall Survival of Hepatocellular Carcinoma After Hepatectomy

Background

A limited number of studies have examined the use of radiomics to predict 3-year overall survival (OS) after hepatectomy in patients with hepatocellular carcinoma (HCC). This study develops 3-year OS prediction models for HCC patients after liver resection using MRI radiomics and clinicopathological factors.

Materials and Methods

A retrospective analysis of 141 patients who underwent surgical resection of HCC was performed. Patients were randomized into two set: the training set (n=98) and the validation set (n=43) including the survival groups (n=111) and non-survival groups (n=30) based on 3-year survival after hepatectomy. Furthermore, x2 or Fisher's exact test, univariate and multivariate logistic regression analyses were conducted to determine independent clinicopathological risk factors associated with 3-year OS. 1688 quantitative imaging features were extracted from preoperative T2-weighted imaging (T2WI) and contrast-enhanced magnetic resonance imaging (CE-MRI) of arterial phase (AP), portal venous phases (PVP)and delay period (DP). The features were selected using the variance threshold method, the select K best method and the least absolute shrinkage and selection operator (LASSO) algorithm. By using Bernoulli Naive Bayes (BernoulliNB) and Multinomial Naive Bayes (MultinomialNB) classifiers, we constructed models based on the independent clinicopathological factors and Rad-scores. To determine the best model, receiver operating characteristics (ROC) and Delong's test were used. Moreover, calibration curves were used to determine the calibration ability of the model, while decision curve analysis (DCA) was implemented to evaluate its clinical benefit.

Results

The fusion model showed excellent prediction precision with AUC of 0.910 and 0.846 in training and validation set and revealed significant diagnostic accuracy and value in the calibration curve and DCA analysis.

Conclusion

Nomograms based on MRI radiomics and clinicopathological factors have significant predictive value for 3-year OS after hepatectomy and can be used for risk classification.

Clinical Efficacy of Gadobutrol: Review of Over 25 Years of Use Exceeding 100 Million Administrations

BACKGROUND

Gadobutrol has been administered more than 100 million times worldwide, since February 1998, that is, over the last 25 years. Numerous clinical studies in a broad range of indications document the long-term experience with gadobutrol.

OBJECTIVE

The aim of this study was to provide a literature-based overview on gadobutrol's efficacy in 9 approved indications and use in children.

MATERIALS AND METHODS

Efficacy results in patients of all age groups including sensitivity, specificity, accuracy, and positive/negative predictive values were identified by a systematic literature search on Embase until December 31, 2022. Nine approved indications were considered: central nervous system (CNS), magnetic resonance angiography (MRA), breast, heart, prostate, kidney, liver, musculoskeletal, whole body, and various indications in children.

RESULTS

Sixty-five publications (10 phase III, 2 phase IV, 53 investigator-initiated studies) reported diagnostic efficacy results obtained from 7806 patients including 271 children, at 369 centers worldwide. Indication-specific sensitivity ranges were 59%-98% (CNS), 53%-100% (MRA), 80%-100% (breast), 64%-90% (heart), 64%-96% (prostate), 71-85 (kidney), 79%-100% (liver), 53%-98% (musculoskeletal), and 78%-100% (children). Indication-specific specificity ranges were 75%-100% (CNS), 64%-99% (MRA), 58%-98% (breast), and 47%-100% (heart).

CONCLUSIONS

The evaluated body of evidence, consisting of 65 studies with 7806 patients, including 271 children and 7535 adults, showed that gadobutrol is an efficacious magnetic resonance imaging contrast agent for all age groups in various approved indications throughout the whole body.

This Is What Metabolic Dysfunction-Associated Steatotic Liver Disease Looks Like: Potential of a Multiparametric MRI Protocol

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent condition with a broad spectrum defined by liver biopsy. This gold standard method evaluates three features: steatosis, activity (ballooning and lobular inflammation), and fibrosis, attributing them to certain grades or stages using a semiquantitative scoring system. However, liver biopsy is subject to numerous restrictions, creating an unmet need for a reliable and reproducible method for MASLD assessment, grading, and staging. Noninvasive imaging modalities, such as magnetic resonance imaging (MRI), offer the potential to assess quantitative liver parameters. This review aims to provide an overview of the available MRI techniques for the three criteria evaluated individually by liver histology. Here, we discuss the possibility of combining multiple MRI parameters to replace liver biopsy with a holistic, multiparametric MRI protocol. In conclusion, the development and implementation of such an approach could significantly improve the diagnosis and management of MASLD, reducing the need for invasive procedures and paving the way for more personalized treatment strategies.

Gadoxetic Acid in MRI: A Five-Year Experience at a High-Complexity Hospital in Colombia

Objective The objective of the study was to evaluate the use of the hepatospecific contrast agent, gadoxetic acid, for MRI in patients at a high-complexity hospital in Medellin, Colombia, from 2016 to 2022. Materials and methods This was an observational, descriptive, and retrospective cross-sectional study involving patients who had undergone MRI with gadoxetic acid from February 2016 to January 2022. The MRI studies were interpreted by two radiologists specializing in body imaging, each with at least 10 years of experience. The medical records of the identified patients were reviewed. Quantitative variables were presented using either means and standard deviations or medians and interquartile ranges, depending on the distribution of the variables. Qualitative variables were represented through absolute and relative frequencies. Results A total of 100 pharmacy records were collected, leading to a final sample of 75 patients aged between three and 91 years. The primary reason for imaging was to assess focal liver lesions in 58 patients (77.3%), with bile duct injury being the second most common indication in 16 patients (21.3%). A diagnostic alteration was noted in 69.3% of cases (52 patients). Among the 58 focal liver lesions analyzed using a hepatospecific agent, 31 cases (53.4%) were diagnosed as focal nodular hyperplasia. Conclusion Our study reinforces the clinical value of gadoxetic acid-enhanced MRI in refining diagnostic assessments, particularly in cases involving bile duct and focal hepatic lesions.

Intra-patient and inter-observer image quality analysis in liver MRI study with gadoxetic acid using two different multi-arterial phase techniques

PURPOSE

To evaluate intra-patient and interobserver agreement in patients who underwent liver MRI with gadoxetic acid using two different multi-arterial phase (AP) techniques.

METHODS

A total of 154 prospectively enrolled patients underwent clinical gadoxetic acid-enhanced liver MRI twice within 12 months, using two different multi-arterial algorithms: CAIPIRINHA-VIBE and TWIST-VIBE. For every patient, breath-holding time, body mass index, sex, age were recorded. The phase without contrast media and the APs were independently evaluated by two radiologists who quantified Gibbs artefacts, noise, respiratory motion artefacts, and general image quality. Presence or absence of Gibbs artefacts and noise was compared by the McNemar's test. Respiratory motion artefacts and image quality scores were compared using Wilcoxon signed rank test. Interobserver agreement was assessed by Cohen kappa statistics.

RESULTS

Compared with TWIST-VIBE, CAIPIRINHA-VIBE images had better scores for every parameter except higher noise score. Triple APs were always acquired with TWIST-VIBE but failed in 37% using CAIPIRINHA-VIBE: 11% have only one AP, 26% have two. Breath-holding time was the only parameter that influenced the success of multi-arterial techniques. TWIST-VIBE images had worst score for Gibbs and respiratory motion artefacts but lower noise score.

CONCLUSION

CAIPIRINHA-VIBE images were always diagnostic, but with a failure of triple-AP in 37%. TWIST-VIBE was successful in obtaining three APs in all patients. Breath-holding time is the only parameter which can influence the preliminary choice between CAIPIRINHA-VIBE and TWIST-VIBE algorithm.

ADVANCES IN KNOWLEDGE

If the patient is expected to perform good breath-holds, TWIST-VIBE is preferable; otherwise, CAIPIRINHA-VIBE is more appropriate.

Diagnostic performance of gadoxetic acid-enhanced abbreviated magnetic resonance imaging protocol in small hepatocellular carcinoma (≤2 cm) in high-risk patients

BACKGROUND

Biannual Ultrasound showed insufficient sensitivity in detecting small or early-stage hepatocellular carcinoma (HCC). Abbreviated magnetic resonance imaging (A-MRI) protocols with fewer sequences demonstrated higher HCC detection sensitivity than ultrasound with acceptable cost and examination time.

PURPOSE

To compare the diagnostic performance of gadoxetic acid-enhanced A-MRI with a full sequence MRI (F-MRI) protocol for small HCC (≤2 cm) in cirrhotic or hepatitis B virus-infected high-risk patients.

MATERIAL AND METHODS

Two hundred and four consecutive patients with 166 pathologically confirmed small HCC who underwent preoperative gadoxetic acid-enhanced MRI were retrospectively included. A-MRI set comprised T1-weighted hepatobiliary phase imaging, T2-weighted imaging, diffusion-weighted imaging and apparent diffusion coefficient mapping. Two independent radiologists blinded to clinical data assessed the A-MRI set and F-MRI set. Per-patient HCC and per-lesion HCC diagnostic performance were compared.

RESULTS

Per-patient HCC detection sensitivity of A-MRI set was 93.8% and 91.2% for observer 1 and observer 2, and, for the F-MRI set, the per-patient HCC detection sensitivity was 96.6% and 95.2%, respectively. There was no significant difference in per-patient sensitivity, specificity and per-lesion HCC detection sensitivity between the two imaging sets for both readers. (P = 0.06-0.25) The A-MRI set showed higher sensitivity on HCC without arterial phase hyperenhancement, and the F-MRI set demonstrated with higher sensitivity on HCC with arterial phase hyperenhancement (P < 0.05).

CONCLUSION

A-MRI using diagnostic criteria including hypointensity on hepatobiliary phase plus mild to moderate hyperintensity on T2-weighted imaging or restricted diffusion demonstrated comparable sensitivity and specificity for small HCC compared to the F-MRI protocol in high-risk patients.

Biliary complications after liver transplantation: A computed tomography and magnetic resonance imaging pictorial review

Biliary complications are the most common complications after liver transplantation. Computed tomography (CT) and magnetic resonance imaging (MRI) are cornerstones for timely diagnosis of biliary complications after liver transplantation. The diagnosis of these complications by CT and MRI requires expertise, mainly with respect to identifying subtle early signs to avoid missed or incorrect diagnoses. For example, biliary strictures may be misdiagnosed on MRI due to size mismatch of the common ducts of the donor and recipient, postoperative edema, pneumobilia, or susceptibility artifacts caused by surgical clips. Proper and prompt diagnosis of biliary complications after transplantation allows the timely initiation of appropriate management. The aim of this pictorial review is to illustrate various CT and MRI findings related to biliary complications after liver transplantation, based on time of presentation after surgery and frequency of occurrence.

Comparison of gadolinium-based contrast agents for MR cholangiography in saline, blood and bile: a phantom study

BACKGROUND

We compared T1- and T2-weighted signal intensities of liver-specific (gadoxetate, gadobenate) and non-specific (gadoterate) gadolinium contrast agents (CAs) in a bile phantom.

METHODS

In a phantom study, gadoxetate, gadobenate, and gadoterate were diluted in saline, blood, and bile at different concentrations (0, 0.25, 0.5. 1, 2.5, 5, 10, and 25 mM) and imaged in a 3-T magnetic resonance imaging (MRI) system using T1- and T2-weighted sequences. The maximum signal intensities of CAs were compared for each sequence separately and across all T1-weighted sequences using one-way ANOVA.

RESULTS

Using T1-weighted sequences, CA concentration-dependent signal intensity increase was followed by decrease due to T2* effects. Comparing CAs for each sequence in bile yielded higher maximum signal intensities with gadobenate than gadoxetate and gadoterate using T1-weighted spin-echo (p < 0.010), multiecho gradient- and spin-echo (p < 0.001), and T1-weighted high-resolution isotropic volume excitation (eTHRIVE) sequences (p < 0.010). Comparing across all T1-weighted sequences in the bile phantom, gadobenate imaged using T1-weighted turbo field-echo (TFE) sequence showed the highest signal intensity, significantly higher than that using other CAs agents or sequences (p < 0.004) except for gadobenate and gadoxetate evaluated with three-dimensional multiecho fast field-echo (3D-mFFE) and gadoxetate with T1-weighted TFE sequence (p > 0.141). Signal reduction with CA concentration-dependent decrease was observed on T2-weighted images.

CONCLUSION

In this bile phantom study of gadolinium-based CA, gadobenate and gadoxetate showed high signal intensity with T1-weighted TFE and 3D-mFFE sequences, which supports their potential utility for contrast-enhanced hepatobiliary MRI.

KEY POINTS

• Contrast-enhanced magnetic resonance (MR) cholangiography depends on contrast agent type, kinetics, and concentration in bile, • We compared signal intensities of three contrast agents in a bile phantom study. • Gadobenate, gadoxetate, and gadoterate demonstrated different signal intensities at identical concentrations. • Gadoxetate and gadobenate showed high signal intensities on T1-weighted MR sequences.

Optimization of hepatobiliary phase imaging in gadoxetic acid-enhanced magnetic resonance imaging: a narrative review

Background and Objective

Gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) is widely used in clinical practice. Its unique hepatobiliary phase (HBP) has been used to improve the detection and identification of hepatic lesions and has also been used to evaluate hepatic function and fibrosis. At the early stage of its clinical practice, the HBP was typically collected empirically with a delay of 20 minutes after intravenous administration to image the liver with sufficient enhancement for diagnosis. However, numerous methods and consensus statements for optimizing HBP acquisition have been proposed. This review details the methods and consensus statements on optimizing HBP collection.

Methods

The electronic literature search was performed using the databases PubMed, MEDLINE, Cochrane, and Embase without limit on publication period to identify published reports on optimizing HBP imaging in Gd-EOB-DTPA-enhanced MRI. Articles with low relevance to the topics were excluded.

Key Content and Findings

Recently, an increasing number of investigations suggest that collecting HBP after 20 min is too drawn-out for patients with normal liver function but is too short for patients with cirrhosis. Previous studies demonstrated that liver enhancement is closely related to liver function in Gd-EOB-DTPA-enhanced MRI. Therefore several reports have proposed various HBP delay times at different liver function levels. These delay times could be evaluated by laboratory indicators, such as prothrombin (PT) activity, total bilirubin, direct bilirubin, and the model for end-stage liver disease. Other investigations have found that the initial visualization time of the intrahepatic bile duct (IHD) in Gd-EOB-DTPA-enhanced MRI to also be related to liver enhancement and function. Therefore, initial visualization of the IHD is considered necessary for adequate HBP and has been employed in HBP acquisition in recent reports.

Conclusions

Optimizing HBP acquisition according to individual hepatic function is a good strategy and was followed in most of the investigations included in our review. Obtaining adequate HBP in the shortest possible time is the target condition in Gd-EOB-DTPA-enhanced MRI. However, a more concise and efficient HBP acquisition strategy is still expected to be developed in the future.

Computer-aided hepatocellular carcinoma detection on the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging using a convolutional neural network: Feasibility evaluation with multi-sequence data

BACKGROUND AND OBJECTIVES

Diagnosis of hepatocellular carcinoma (HCC) on liver MRI needs analysis of multi-sequence images. However, developing computer-aided detection (CAD) for every single sequence requires considerable time and labor for image segmentation. Therefore, we developed CAD for HCC on the hepatobiliary phase (HBP) of gadoxetic acid-enhanced magnetic resonance imaging (MRI) using a convolutional neural network (CNN) and evaluated its feasibility on multi-sequence, multi-unit, and multi-center data.

METHODS

Patients who underwent gadoxetic acid-enhanced MRI and surgery for HCC in Korea University Anam Hospital (KUAH) and Korea University Guro Hospital (KUGH) were reviewed. Finally, 170 nodules from 155 consecutive patients from KUAH and 28 nodules from 28 patients randomly selected from KUGH were included. Regions of interests were drawn on the whole HCC volume on HBP, T1-weighted (T1WI), T2-weighted (T2WI), and portal venous phase (PVP) images. The CAD was developed from the HBP images of KUAH using customized-nnUNet and post-processed for false-positive reduction. Internal and external validation of the CAD was performed with HBP, T1WI, T2WI, and PVP of KUAH and KUGH.

RESULTS

The figure of merit and recall of the jackknife alternative free-response receiver operating characteristic of the CAD for HBP, T1WI, T2WI, and PVP at false-positive rate 0.5 were (0.87 and 87.0), (0.73 and 73.3), (0.13 and 13.3), and (0.67 and 66.7) in KUAH and (0.86 and 86.0), (0.61 and 53.6), (0.07 and 0.07), and (0.57 and 53.6) in KUGH, respectively.

CONCLUSIONS

The CAD for HCC on gadoxetic acid-enhanced MRI developed by CNN from HBP detected HCCs feasibly on HBP, T1WI, and PVP of gadoxetic acid-enhanced MRI obtained from multiple units and centers. This result imply that the CAD developed using single MRI sequence may be applied to other similar sequences and this will reduce labor and time for CAD development in multi-sequence MRI.

Portal hypertension may influence the registration of hypointensity of small hepatocellular carcinoma in the hepatobiliary phase in gadoxetic acid MR

BACKGROUND

The aim of the study was to analyze the association between the liver uptake of Gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) in the hepatobiliary phase (HBP) in cirrhotic patients and the presence of clinically significant portal hypertension (CSPH), and how these features impact on hepatocellular carcinoma (HCC) detection in the HBP.

PATIENTS AND METHODS

Post-hoc analysis of a prospective cohort of 62 cirrhotic patients with newly US-detected nodule between 1-2 cm (study group). Twenty healthy subjects were used as control group. Qualitative and quantitative analysis of the liver contrast uptake in the HBP assessed by Relative Liver-Enhancement (RLE), Liver-Spleen (LSCR), Liver-Muscle (LMCR), and Liver-Kidney Contrast-Ratio (LKCR), Contrast Enhancement Index (CEI), and Hepatic Uptake (HUI), and biliary excretion, were registered. CSPH was confirmed invasively (HVPG > 10 mmHg) or by indirect parameters. The appearance of HCC at the HBP was analyzed.

RESULTS

Nineteen patients (30.6%) did not have CSPH. In 41 patients (66.1%) the final diagnosis was HCC. All indices were significantly higher in the control group, indicating a more intense HBP liver signal intensity compared to patients with cirrhosis, even if the comparison was restricted to patients with no CSPH. CSPH was associated to a lower rate of HCC hypointensity in the HBP (51.9% vs. 85.7% without CSPH, p = 0.004).

CONCLUSIONS

Liver uptake of Gd-EOB-DTPA at the HBP is decreased in cirrhosis even if the liver function is minimally impaired and it falls down significantly in patients with CSPH compromising the recognition of hypointense lesions. This fact may represent a limitation for the detection of small HCC in patients with cirrhosis and CSPH.

The value of gadobenate dimeglumine-enhanced biliary imaging from the hepatobiliary phase for predicting post-hepatectomy liver failure in HCC patients

OBJECTIVES

To determine the value of gadobenate dimeglumine-enhanced biliary imaging from the hepatobiliary phase for predicting post-hepatectomy liver failure (PHLF) in patients with hepatocellular carcinoma (HCC).

METHODS

Patients with HCC who underwent gadobenate dimeglumine-enhanced hepatobiliary magnetic resonance imaging prior to hepatectomy were collected in two centers. The relative enhancement ratio of the biliary system (REB) and the liver to muscle ratio (LMR) were measured at the hepatobiliary phase. Potential risk factors for PHLF were analyzed by logistic regression. The capacity of the REB and LMR to predict PHLF was analyzed via receiver operating characteristic curve.

RESULTS

Of the 221 patients, post-hepatectomy liver failure occurred in 60 patients (27.1%). The REB was an independent risk factor for PHLF (odds ratio [OR] = 0.127 [0.047-0.348], p < 0.001). Although the LMR tended to be associated with PHLF (p = 0.063), it was not an independent risk factor in the multivariable analysis (OR = 0.624 [0.023-16.709], p = 0.779). Moreover, the area under the receiver operating characteristic curve of the REB and LMR was 0.87 and 0.60. The most appropriate cutoff value for the REB was 2.21. The HCC patients with the REB ≤ 2.21 had a higher incidence of post-hepatectomy liver failure than those with the REB > 2.21 (60.0% versus 8.5%, p < 0.001).

CONCLUSIONS

Gadobenate dimeglumine-enhanced biliary imaging from the hepatobiliary phase was valuable in predicting post-hepatectomy liver failure in HCC patients.

KEY POINTS

• The relative enhancement ratio of the biliary system (REB) was an independent risk factor for post-hepatectomy liver failure in HCC patients. • HCC patients with the REB ≤ 2.21 had significantly higher incidence of post-hepatectomy liver failure than those with the REB > 2.21 (60.0% versus 8.5%).

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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