Presence of non-hypervascular hypointense nodules on Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging in patients with hepatocellular carcinoma

An overview of risk assessment and monitoring of malignant transformation in cirrhotic nodules

Cirrhotic liver nodules can progress to hepatocellular carcinoma (HCC) through a multi-step carcinogenesis model, with dysplastic nodules being particularly high risk. Currently, monitoring the progression of non-HCC cirrhotic nodules is primarily through dynamic observation, but there is a lack of sensitive, efficient, and convenient methods. Dynamic monitoring and risk evaluation of malignant transformation are essential for timely treatment and improved patient survival rates. Routine liver biopsies are impractical for monitoring, and imaging techniques like ultrasound, computed tomography, and magnetic resonance imaging are not suitable for all patients or for accurately assessing subcentimeter nodules. Identifying serum biomarkers with high sensitivity, specificity, and stability, and developing a multi-index evaluation model, may provide a more convenient and efficient approach to monitoring pathological changes in cirrhotic nodules.

Liver Lesions at Risk of Transformation into Hepatocellular Carcinoma in Cirrhotic Patients: Hepatobiliary Phase Hypointense Nodules without Arterial Phase Hyperenhancement

Recent technical advances in liver imaging and surveillance for patients at high risk for developing hepatocellular carcinoma (HCC) have led to an increase in the detection of borderline hepatic nodules in the gray area of multistep carcinogenesis, particularly in those that are hypointense at the hepatobiliary phase (HBP) and do not show arterial phase hyperenhancement. Given their potential to transform and advance into hypervascular HCC, these nodules have progressively attracted the interest of the scientific community. To date, however, no shared guidelines have been established for the decision management of these borderline hepatic nodules. It is therefore extremely important to identify features that indicate the malignant potential of these nodules and the likelihood of vascularization. In fact, a more complete knowledge of their history and evolution would allow outlining shared guidelines for their clinical-surgical management, to implement early treatment programs and decide between a preventive curative treatment or a watchful follow-up. This review aims to summarize the current knowledge on hepatic borderline nodules, particularly focusing on those imaging features which are hypothetically correlated with their malignant evolution, and to discuss current guidelines and ongoing management in clinical practice.

Microvascular invasion-negative hepatocellular carcinoma: Prognostic value of qualitative and quantitative Gd-EOB-DTPA MRI analysis

OBJECTIVES

The purpose of this study was to establish a model for predicting the prognosis of patients with microvascular invasion (MVI)-negative hepatocellular carcinoma (HCC) based on qualitative and quantitative analyses of Gd-EOB-DTPA magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Consecutive patients with MVI-negative HCC who underwent preoperative Gd-EOB-DTPA MRI between January 2015 and December 2019 were retrospectively enrolled.In total, 122 patients were randomly assigned to the training and validation groups at a ratio of 7:3. Univariate and multivariate logistic regression analyses were performed to identify significant clinical parameters and MRI features, including quantitative and qualitative parameters associated with prognosis, which were incorporated into a predictive nomogram. The end-point of this study was recurrence-free survival. Outcomes were compared between groups using the Kaplan-Meier method with the log-rank test.

RESULTS

During a median follow-up period of 58.86 months, 38 patients (31.15 %) experienced recurrence. Multivariate analysis revealed that lower relative enhancement ratio (RER), hepatobiliary phase hypointensity without arterial phase hyperenhancement, Liver Imaging Reporting and Data System category, mild-moderate T2 hyperintensity, and higher aspartate aminotransferase levels were risk factors associated with prognosis and then incorporated into the prognostic model. C-indices for training and validation groups were 0.732 and 0.692, respectively. The most appropriate cut-off value for RER was 1.197. Patients with RER ≤ 1.197 had significantly higher postoperative recurrence rates than those with RER > 1.197 (p = 0.004).

CONCLUSION

The model integrating qualitative and quantitative imaging parameters and clinical parameters satisfactorily predicted the prognosis of patients with MVI-negative HCC.

Magnetic resonance imaging for treatment response evaluation and prognostication of hepatocellular carcinoma after thermal ablation

Hepatocellular carcinoma (HCC) accounts for the vast majority of primary liver cancer and constitutes a major global health challenge. Tumor ablation with either radiofrequency ablation (RFA) or microwave ablation (MWA) is recommended as a curative-intent treatment for early-stage HCC. Given the widespread use of thermal ablation in routine clinical practice, accurate evaluation of treatment response and patient outcomes has become crucial in optimizing individualized management strategies. Noninvasive imaging occupies the central role in the routine management of patients with HCC. Magnetic resonance imaging (MRI) could provide full wealth of information with respect to tumor morphology, hemodynamics, function and metabolism. With accumulation of liver MR imaging data, radiomics analysis has been increasingly applied to capture tumor heterogeneity and provide prognostication by extracting high-throughput quantitative imaging features from digital medical images. Emerging evidence suggests the potential role of several qualitative, quantitative and radiomic MRI features in prediction of treatment response and patient prognosis after ablation of HCC. Understanding the advancements of MRI in the evaluation of ablated HCCs may facilitate optimal patient care and improved outcomes. This review provides an overview of the emerging role of MRI in treatment response evaluation and prognostication of HCC patients undergoing ablation. CLINICAL RELEVANCE STATEMENT: MRI-based parameters can help predict treatment response and patient prognosis after HCC ablation and thus guide treatment planning. KEY POINTS: 1. ECA-MRI provides morphological and hemodynamic assessment of ablated HCC. 2. EOB-MRI provides more information for tumor response prediction after ablation. 3. DWI improve the characterization of HCC and optimize treatment decision. 4. Radiomics analysis enables characterization of tumor heterogeneity guidance of clinical decision-making. 5. Further studies with multiple radiologists and sufficient follow-up period are needed.

Hypervascular transformation of hepatobiliary phase hypointense nodules without arterial phase hyperenhancement on gadoxetic acid-enhanced MRI: long-term follow-up in a surveillance cohort

OBJECTIVES

With the increasing use of gadoxetic acid-enhanced MRI for HCC surveillance, hepatobiliary phase (HBP) hypointense nodules without arterial phase hyperenhancement (APHE) are frequently encountered. We investigated the rate of these nodules with hypervascular transformation, which suggests hepatocarcinogenesis, by using a prospectively collected longitudinal surveillance cohort data.

METHODS

This study included 382 prospectively enrolled patients at high risk for developing HCC who underwent 1-3 rounds of bi-annual surveillance gadoxetic acid-enhanced MRI. MRI was analyzed to detect HBP hypointense nodules without APHE. Follow-up dynamic CTs and MRIs were evaluated to detect hypervascular transformation of the nodules. Cox proportional hazards regression analyses were used to find predictors for hypervascular transformation.

RESULTS

A total of 76 HBP hypointense nodules without APHE were found in 48 patients, giving a prevalence of 12.6% (48/382). The mean nodule size was 10.8 mm, with 43.4% (33/76) being ≥ 10 mm. Over a median follow-up of 78.6 months, 19 nodules (25.0%) showed hypervascular transformation, all of which demonstrated typical imaging features of HCC. On multivariable Cox-regression analysis, size (≥ 10 mm) was the only independent predictor of hypervascular transformation (hazard ratio, 3.31; 95% confidence interval, 1.21-9.05). The cumulative incidence of hypervascular transformation at 12 and 60 months of nodules ≥ 10 mm was 12.3% and 50.4%, respectively, while that of nodules < 10 mm was 2.5% and 13.9%, respectively.

CONCLUSIONS

About half of the HBP hypointense nodules ≥ 10 mm without APHE transformed to HCC at 5 years of follow-up, indicating the necessity for cautious monitoring with an augmented and extended follow-up schedule for these nodules.

KEY POINTS

• The prevalence of HBP hypointense nodules without APHE was 12.6% in a prospectively recruited population at high risk of developing HCC. • Nodule size ≥ 10 mm was significantly associated with hypervascular transformation, and approximately half of the HBP hypointense nodules ≥ 10 mm without APHE transformed to HCC during 5 years of follow-up. • Given the risk of malignant transformation, HBP hypointense nodules ≥ 10 mm without APHE should be closely monitored.

Risk Factors for Hypervascularization in Hepatobiliary Phase Hypointense Nodules without Arterial Phase Hyperenhancement: A Systematic Review and Meta-analysis

RATIONALE AND OBJECTIVES

To perform a systematic review and meta-analysis to determine risk factors for hypervascularization in hepatobiliary phase (HBP) hypointense nodules without arterial phase hyperenhancement (APHE) in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Pubmed and EMBASE databases were searched up to May 7, 2020. Studies which evaluated radiologic and clinical risk factors for hypervascularization in HBP hypointense nodules without APHE were included. Hazard ratios were meta-analytically pooled using random-effects model. Methodological quality of included studies was assessed using Quality in Prognostic Studies (QUIPS) tool.

RESULTS

Sixteen studies with 934 patients were included. HBP hypointense nodules without APHE with baseline size greater than 10 mm, T2 hyperintensity, and restricted diffusion showed risk for hypervascularization with pooled HRs of 2.95 (95% confidence interval [CI], 1.94-4.20), 4.21 (95% CI, 1.15-15.40), 5.83 (95% CI, 1.42-23.95), respectively. Previous HCC history contributed to hypervascularization of the nodules with hazard ratio of 2.06 (95% CI, 1.23-3.44). T1 hyperintensity, intralesional fat, Child-Pugh Class B, sex, alfa-fetoprotein, hepatitis B or C infection were not significant risk factors for hypervascularization (p ≥0.05). Study quality was generally moderate.

CONCLUSION

HBP hypointense nodules without APHE on gadoxetic acid-enhanced MRI with baseline size greater than 10 mm, T2 hyperintensity, restricted diffusion and previous hepatocellular carcinoma history pose higher risk for hypervascularization. Proper patient management in patients with HBP hypointense nodules without APHE on gadoxetic acid-enhanced MRI may need to be tailored according to these risk factors.

MR Imaging Contrast Agents: Role in Imaging of Chronic Liver Diseases

Contrast-enhanced MR imaging plays an important role in the evaluation of patients with chronic liver disease, particularly for detection and characterization of liver lesions. The two most commonly used contrast agents for liver MR imaging are extracellular agents (ECAs) and hepatobiliary agents (HBAs). In patients with liver disease, the main advantage of ECA-enhanced MR imaging is its high specificity for the diagnosis of progressed HCCs. Conversely, HBAs have an additional contrast mechanism, which results in high liver-to-lesion contrast and highest sensitivity for lesion detection in the hepatobiliary phase. Emerging data suggest that features depicted on contrast-enhanced MR imaging scans are related to tumor biology and are predictive of patients' prognosis, likely to further expand the role of contrast-enhanced MR imaging in the clinical care of patients with chronic liver disease.

Magnetic Resonance Imaging With Extracellular Contrast Detects Hepatocellular Carcinoma With Greater Accuracy Than With Gadoxetic Acid or Computed Tomography

BACKGROUND & AIMS

Computed tomography (CT) and magnetic resonance imaging (MRI) are used to detect hepatocellular carcinoma (HCC). We performed a prospective study to compare the diagnostic performance of CT, MRI with extracellular contrast agents (ECA-MRI), and MRI with hepatobiliary agents (HBA-MRI) in the detection of HCC using the liver imaging reporting and data system (LI-RADS).

METHODS

We studied 125 participants (102 men; mean age, 55.3 years) with chronic liver disease who underwent CT, ECA-MRI, or HBA-MRI (with gadoxetic acid) before surgery for a nodule initially detected by ultrasound at a tertiary center in Korea, from November 2016 through February 2019. We collected data on major features and assigned LI-RADS categories (v2018) from CT and MRI examinations. We then compared the diagnostic performance for LR-5 for each modality alone, and in combination.

RESULTS

In total, 163 observations (124 HCCs, 13 non-HCC malignancies, and 26 benign lesions; mean size, 20.7 mm) were identified. ECA-MRI detected HCC with 83.1% sensitivity and 86.6% accuracy, compared to 64.4% sensitivity and 71.8% accuracy for CT (P < .001) and 71.2% sensitivity (P = .005) and 76.5% accuracy for HBA-MRI (P = .005); all technologies detected HCC with 97.4% specificity. Adding CT to either ECA-MRI (89.2% sensitivity, 91.4% accuracy; both P < .05) or HBA-MRI (82.8% sensitivity, 86.5% accuracy; both P < .05) significantly increased its diagnostic performance in detection of HCC compared with the MRI technologies alone. ECA-MRI identified arterial phase hyperenhancement in a significantly higher proportion of patients (97.6%) than CT (81.5%; P < .001) or HBA-MRI (89.5%; P = .002). ECA-MRI identified non-peripheral washout in 79.8% of patients, vs 74.2% of patients for CT and 73.4% of patients for HBA-MRI (differences not significant). ECA-MRI identified enhancing capsules in 85.5% of patients, vs 33.9% for CT (P < .001) and 41.4% for HBA-MRI (P < .001).

CONCLUSION

In a prospective study of patients with chronic liver disease and a nodule detected by ultrasound, ECA-MRI detected HCC with higher levels of sensitivity and accuracy than CT or HBA-MRI, based on LI-RADS. Diagnostic performance was best when CT was used in combination with MRI compared with MRI alone.

Gadoxetic acid-enhanced MRI radiomics signature: prediction of clinical outcome in hepatocellular carcinoma after surgical resection

BACKGROUND

This study aimed to evaluate the efficiency of gadoxetic acid-enhanced MRI-based radiomics features for prediction of overall survival (OS) in hepatocellular carcinoma (HCC) patients after surgical resection.

METHODS

This prospective study approved by the Institutional Review Board enrolled 120 patients with pathologically confirmed HCC. Radiomics signatures (rad-scores) were built from radiomics features in 3 different regions of interest (ROIs) with the least absolute shrinkage and selection operator (LASSO) cox regression analysis. Preoperative clinical characteristics and semantic imaging features potentially associated with patient survival were evaluated to develop a clinic-radiological model. The radiomics features and clinic-radiological predictors were integrated into a joint model using multivariable Cox regression analysis. Kaplan-Meier analysis and log-rank tests were performed to compare the discriminative performance and evaluated on the validation cohort.

RESULTS

The radiomics signatures showed a significant association with patient survival in both cohorts (all P<0.001). The BCLC (Barcelona clinic liver cancer) stage, non-smooth tumor margin, and the combined rad-score were independently associated with OS. Moreover, the combined model incorporating with clinic-radiological and radiomics features showed an improved predictive performance with C-index of 0.92 [95% confidence interval (CI): 0.87-0.97], compared to the clinic-radiological model (C-index, 0.86, 95% CI: 0.79-0.94; P=0.039) or the combined rad-score (C-index, 0.88, 95% CI: 0.81-0.95; P=0.016).

CONCLUSIONS

Radiomics features along with clinic-radiological predictors can efficiently aid in preoperative HCC prognosis prediction after surgical resection and enable a step forward precise medicine.

Surgical Indications for Hepatocellular Carcinoma with Non-hypervascular Hypointense Nodules Detected by Gd-EOB-DTPA-Enhanced MRI

BACKGROUND

The surgical indication for non-hypervascular hypointense nodules (NHVN) detected incidentally on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) for classical hepatocellular carcinoma (HCC) is unknown. Our aim is to clarify the long-term outcomes in patients with this finding.

METHODS

We reviewed the cases of 290 HCC patients, including 66 patients with NHVN, who underwent Gd-EOB-MRI prior to hepatectomy, between October 2008 and December 2017 at our center. We divided the patients into three groups: a no-NHVN group, a treated NHVN group, and an untreated NHVN group.

RESULTS

There was no significant difference in (RFS) or overall survival (OS) between the no-NHVN and untreated NHVN groups (p = 0.103 and 0.103, respectively). There was no significant difference between these two groups after propensity score matching. Multivariate analyses showed that microscopic intrahepatic metastases and the size of the main classical HCC, the target tumor, were independent prognostic factors of overall survival, but the presence of non-hypervascular hypointense nodules was not. There was no significant difference in RFS or OS between the treated NHVN and untreated NHVN groups (p = 0.158 and 0.109, respectively).

CONCLUSIONS

Non-hypervascular hypointense nodules detected incidentally on Gd-EOB-MRI associated with targeted hypervascular HCC did not reflect prognosis of HCC after hepatectomy. Surgical procedures for classical enhancing HCC may be performed even if non-hypervascular hypointense nodules adjacent to the targeted HCC cannot be removed completely.

Hypovascular hepatic nodules as a predictive factor for transcatheter arterial chemoembolization refractoriness in hepatocellular carcinoma

AIM

Intermediate-stage hepatocellular carcinoma (HCC) targeted for transcatheter arterial chemoembolization (TACE) corresponds to a highly heterogeneous population for whom the factors predicting TACE efficacy have not been established. This study aimed to evaluate the impact of hypovascular hepatic nodules coexisting with intermediate-stage HCC as a significant predictive factor for TACE refractoriness.

METHODS

A total of 66 patients with intermediate-stage HCC who received initial TACE were retrospectively analyzed. Hypovascular hepatic nodules were detected by dynamic computed tomography or magnetic resonance imaging, as well as angiography, before all initial TACE. The time to TACE refractoriness (TTTR) was defined as the period from initial TACE until the diagnosis of TACE refractoriness.

RESULTS

Hypovascular hepatic nodules were detected in 36 patients (54.5%), 15 (41.7%) of whom had a single nodule, whereas 21 (58.3%) had multiple nodules, and the median size of the maximum nodule was 10 mm (range 5-80 mm). The median TTTR was 17.4 months for all patients, and 7.3 and 33.1 months for patients with and without hypovascular hepatic nodules, respectively. The TTTR was significantly shorter for patients with hypovascular hepatic nodules than that for the other patients. In the multivariate analysis, the presence of hypovascular hepatic nodules (HR 7.016, 95% CI 3.534-13.930; P < 0.001) and being out of the up-to-seven criteria (HR 2.861, 95% CI 1.493-5.486; P = 0.002) were independent risk factors for a short TTTR.

CONCLUSIONS

The presence of hypovascular hepatic nodules with intermediate-stage HCC represents a significant predictive risk factor for TACE refractoriness.

Hepatobiliary phase hypointense nodule without arterial phase hyperenhancement as a risk factor for late recurrence (>1 year) of hepatocellular carcinoma after surgery

AIM

To evaluate the value of magnetic resonance imaging (MRI) features, including liver stiffness measured by magnetic resonance elastography (MRE) and the presence of hepatobiliary phase (HBP) hypointense nodule without arterial phase hyperenhancement (APHE), for predicting late recurrence (>1 year) after surgery for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This retrospective study included 124 consecutive patients who had undergone surgery for HCC and preoperative MRI. After excluding patients with early recurrence within 1 year after surgery, 89 patients were analysed. Preoperative MRI images were reviewed by a radiologist to record imaging findings, including (1) liver stiffness by MRE, (2) size of the HCCs, (3) number of HCCs, and (4) presence of HBP hypointense nodule without APHE. Pathological findings included tumour grade, vascular/biliary/capsule invasion, and fibrosis stage of the liver. Considering imaging/pathological findings and patients' characteristics as dependent variables, Cox proportional hazards model analysis was performed to identify independent factors associated with late recurrence after surgery.

RESULTS

The median follow-up period was 37.3 months. During follow-up, 29 patients (32.5%) developed late recurrence after surgery. In multivariate analysis, underlying liver disease (viral hepatitis) and presence of HBP hypointense nodules without APHE (p=0.010 and 0.033, respectively) were independently associated with disease-free survival (DFS). Kaplan-Meier analysis revealed that patients with HBP hypointense nodules without APHE had a significantly lower DFS rate than those without the nodule (39.2% versus 74.1% at 3 years after surgery, p=0.008).

CONCLUSION

The presence of HBP hypointense nodules without APHE was an indicator of late recurrence after surgery for HCC.

Use of gadoxetate disodium in patients with chronic liver disease and its implications for liver imaging reporting and data system (LI-RADS)

Use of gadoxetate disodium, a hepatobiliary gadolinium-based agent, in patients with chronic parenchymal liver disease offers the advantage of improved sensitivity for detecting hepatocellular carcinoma (HCC). Imaging features of liver observations on gadoxetate-enhanced MRI may also serve as biomarkers of recurrence-free and overall survival following definitive treatment of HCC. A number of technical and interpretative pitfalls specific to gadoxetate exist, however, and needs to be recognized when protocoling and interpreting MRI exams with this agent. This article reviews the advantages and pitfalls of gadoxetate use in patients at risk for HCC, and the potential impact on Liver Imaging Reporting and Data System (LI-RADS) imaging feature assessment and categorization. Level of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:1236-1252.

Usefulness of Gd-EOB-DTPA-enhanced MRI for evaluating the potential for early development of hepatocellular carcinoma after HCV eradication by direct-acting antiviral treatment

Objective: The development of hepatocellular carcinoma (HCC) is not uncommon in patients who achieve eradication of the hepatitis C virus through direct-acting antiviral (DAA) treatment. The aim of this study was to identify the patients at high risk for novel HCC development after a sustained virologic response (SVR) by DAA treatment. Patients and Methods: A total of 518 patients with no history of HCC treatment and who achieved SVR by DAA treatment were evaluated retrospectively. The correlations between HCC development and the patients' characteristics were evaluated. For patients who underwent gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) or dynamic contrast-enhanced computed tomography, the relationship between the imaging findings and subsequent HCC development was also assessed. Results: HCC developed newly in 22 patients, and the 1-year and 3-year cumulative HCC rates were 2.0% and 8.5%, respectively. In multivariate analysis, a FIB-4 index >4.0 and a post-treatment α-fetoprotein >4.0 ng/ml were significant risk factors for HCC. In 26 of 118 patients who underwent an MRI before DAA treatment, a non-hypervascular hypo-intense nodule was seen in the hepatobiliary phase, and in 6 of 182 patients who underwent a CT, a non-hypervascular hypo-enhanced nodule was seen in the delayed phase. The sensitivity and specificity of the MRI-positive findings for the subsequent development of HCC were 0.92 and 0.87, respectively, and those of the CT were 0.40 and 0.99, respectively. In multivariate analysis of patients who underwent an MRI, a non-hypervascular hypo-intense nodule was the only factor that was significantly related to HCC development (HR 32.4, p = 0.001). Conclusion: Gd-EOB-DTPA-enhanced MRI was found to be reliable for risk evaluation of subsequent HCC development in patients after SVR by DAA treatment. Patients with a non-hypervascular hypo-intense nodule need more careful observation for incident HCC.

T1 mapping on gadoxetic acid-enhanced MR imaging predicts recurrence of hepatocellular carcinoma after hepatectomy

PURPOSE

Our purpose was to demonstrate the prognostic significance of T₁ mapping on gadoxetic acid-enhanced MR imaging in prediction of recurrence of single HCC after hepatectomy.

MATERIALS AND METHODS

One hundred and seven patients with single nodular HCC (≤3 cm) who underwent preoperative gadoxetic acid-enhanced MRI were included in the study. T₁ mapping with syngo MapIt was obtained on a 1.5 T scanner. Radiological features and reduction rate of T₁ relaxation time (Δ%) of tumors were assessed by two radiologists. Cumulative recurrence rates were compared between groups of low and high reduction rate of T₁ relaxation time. A further classified cumulative recurrence rate of the overall cohort was based on the numbers of independent predictive factors.

RESULTS

Reduction rate of T₁ relaxation time (P = 0.001) and non-hypervascular hypointense nodules (P = 0.042) in preoperative gadoxetic acid-enhanced MRI were independently related to recurrence of HCC after hepatectomy. Patients of lower reduction rates group had higher cumulative recurrence rates (P < 0.0001) than patients of higher reduction rates group. A combination of the two risk factors in patients with single HCC had significantly higher recurrence rates compared to those with either or none of the two risk factors.

CONCLUSIONS

Reduction rate of T₁ relaxation time combined with non-hypervascular hypointense nodules can be reliable biomarkers in the preoperative prediction of recurrence of HCC after hepatectomy.