New OPTN/UNOS policy for liver transplant allocation: standardization of liver imaging, diagnosis, classification, and reporting of hepatocellular carcinoma

Vasomics of the liver

Chronic liver disease is a cluster of disorders associated with complex haemodynamic alterations, which is characterised by structural and functional disruptions of the intrahepatic and extrahepatic vasculature. 'Vasomics' is an emerging omics discipline that comprehensively analyses and models the vascular system by integrating pathophysiology of disease, biomechanics, medical imaging, computational science and artificial intelligence. Vasomics is further typified by its multidimensional, multiscale and high-throughput nature, which depends on the rapid and robust extraction of well-defined vascular phenotypes with clear clinical and/or biological interpretability. By leveraging multimodality medical imaging techniques, vascular functional assessments, pathological image evaluation, and related computational methods, integrated vasomics provides a deeper understanding of the associations between the vascular system and disease. This in turn reveals the crucial role of the vascular system in disease occurrence, progression and treatment responses, thereby supporting precision medicine approaches. Pathological vascular features have already demonstrated their key role in different clinical scenarios. Despite this, vasomics is yet to be widely recognised. Therefore, we furnished a comprehensive definition of vasomics providing a classification of existing hepatic vascular phenotypes into the following categories: anatomical, biomechanical, biochemical, pathophysiological and composite.

The Role of Liver Transplantation in Hepatocellular Carcinoma

Liver transplantation (LT) is the standard-of-care for early hepatocellular carcinoma (HCC). Current selection criteria depend primarily on measures of tumor burden and alpha-fetoprotein levels. Evolving strategies include the application of prognostic scores and the development of specialized molecular markers to predict recurrence. New technologies such as machine perfusion of donor organs are expected to dramatically improve the availability and access to LT in HCC.

Downstaging of hepatocellular carcinoma before liver transplantation: Results from a national multicenter prospective cohort study

BACKGROUND AND AIMS

Patients with HCC meeting United Network for Organ Sharing (UNOS)-downstaging (DS) criteria have excellent post-liver transplantation (LT) outcomes. Studies on HCC beyond UNOS-DS criteria ("All-Comers" [AC]) have been limited by small sample size and short follow-up time, prompting this analysis.

APPROACH AND RESULTS

Three hundred twenty-six patients meeting UNOS-DS and 190 meeting AC criteria from 9 LT centers across 5 UNOS regions were enrolled from 2015 to 2023 and prospectively followed. Competing risk analysis and Kaplan-Meier method were used to evaluate DS and LT outcomes, and Fine-and-Gray and Cox models were used to identify predictors of outcomes. AC and UNOS-DS had similar median alpha-fetoprotein (15 vs. 12 ng/mL; p =0.08), MELD (9 vs. 9; p =0.52), and Child-Pugh (A vs. A; p =0.30). Two years after the first local regional therapy, 82% of UNOS-DS and 66% of AC were successfully downstaged ( p <0.001). In AC, DS rates were 72% for tumor number plus diameter of largest lesion <10, 51% for sum 10-12, and 39% for sum >12 ( p =0.01). Yttrium-90 achieved higher DS success than transarterial chemoembolization in AC (74% vs. 65%; p <0.001). 48% of UNOS-DS and 40% of AC underwent LT ( p =0.10). Five-year post-LT survival was similar between UNOS-DS and AC (74% vs. 72%; p =0.77), although 5-year post-LT recurrence was higher in AC (30% vs. 14%; p =0.02).

CONCLUSIONS

Despite higher HCC recurrence and lower intention-to-treat survival in AC, post-LT survival was comparable between UNOS-DS and AC. Yttrium-90 attained higher DS success than transarterial chemoembolization in AC. LT after DS is feasible in AC, though defining an upper limit in tumor burden may be necessary.

Using Voxel-Based Dosimetry to Evaluate Sphere Concentration and Tumor Dose in Hepatocellular Carcinoma Treated with Yttrium-90 Radiation Segmentectomy with Glass Microspheres

PURPOSE

To utilize voxel-based dosimetry following radiation segmentectomy (RS) to understand microsphere distribution and validate current literature regarding radiologic and pathologic outcomes.

MATERIALS AND METHODS

A retrospective, single-center analysis of patients with solitary hepatocellular carcinoma (N = 56) treated with yttrium-90 (90Y) RS with glass microspheres (Therasphere; Boston Scientific, Marlborough, Massachusetts) from 2020 to 2022 was performed. Posttreatment voxel-based dosimetry was evaluated using Mirada DBx Build 1.2.0 Simplicit90Y software (Boston Scientific) and utilized to calculate sphere concentration to tumor as well as D70 (minimum dose to 70% total tumor volume), D90, and D99. Time to progression (TTP), treatment response, and adverse events were studied.

RESULTS

Fifty-six solitary tumors were analyzed with a median tumor diameter of 3.4 cm (range, 1.2-6.8 cm) and median tumor absorbed dose of 732 Gy (range, 252-1,776 Gy). Median sphere activity (SA) at the time of delivery was 1,446 Bq (range, 417-2,621 Bq). Median tumor sphere concentration was 12,868 spheres/mL (range, 2,655-37,183 spheres/mL). Sphere concentration into tumor and normal tissue was inversely correlated with perfused treatment volume (R2 = 0.21 and R2 = 0.39, respectively). Of the 51 tumors with posttreatment imaging, objective response was noted in 49 patients (96%) and complete response in 42 patients (82%). The median TTP was not reached with a 2-year progression rate of 11%. Fifteen patients underwent liver transplant. Median tumor necrosis was 99% (range, 80%-100%). Lower tumor volumes and higher D99 were associated with complete pathologic necrosis (P < .001 and P = .022, respectively).

CONCLUSIONS

Voxel-based dosimetry following 90Y radioembolization can be utilized to account for sphere deposition and distribution into tumor. Ablative RS with high SA yields durable radiologic and pathologic outcomes.

LI-RADS v2018 category and imaging features: inter-modality agreement between contrast-enhanced CT, gadoxetate disodium-enhanced MRI, and extracellular contrast-enhanced MRI

PURPOSE

To perform an intra-individual comparison of LI-RADS category and imaging features in patients at high risk of hepatocellular carcinoma (HCC) on contrast-enhanced CT, gadoxetate disodium-enhanced MRI (EOB-MRI), and extracellular agent-enhanced MRI (ECA-MRI) and to analyze the diagnostic performance of each imaging modality.

METHOD

This retrospective study included cirrhotic patients with at least one LR-3, LR-4, LR-5, LR-M or LR-TIV observation imaged with at least two imaging modalities among CT, EOB-MRI, or ECA-MRI. Two radiologists evaluated the observations using the LI-RADS v2018 diagnostic algorithm. Reference standard included pathologic confirmation and imaging criteria according to LI-RADS v2018. Imaging features were compared between different exams using the McNemar test. Inter-modality agreement was calculated by using the weighted Cohen's kappa (k) test.

RESULTS

A total of 144 observations (mean size 34.0 ± 32.4 mm) in 96 patients were included. There were no significant differences in the detection of major and ancillary imaging features between the three imaging modalities. When considering all the observations, inter-modality agreement for category assignment was substantial between CT and EOB-MRI (k 0.60; 95%CI 0.44, 0.75), moderate between CT and ECA-MRI (k 0.46; 95%CI 0.22, 0.69) and substantial between EOB-MRI and ECA-MRI (k 0.72; 95%CI 0.59, 0.85). In observations smaller than 20 mm, inter-modality agreement was fair between CT and EOB-MRI (k 0.26; 95%CI 0.05, 0.47), moderate between CT and ECA-MRI (k 0.42; 95%CI -0.02, 0.88), and substantial between EOB-MRI and ECA-MRI (k 0.65; 95%CI 0.47, 0.82). ECA-MRI demonstrated the highest sensitivity (70%) and specificity (100%) when considering LR-5 as predictor of HCC.

CONCLUSIONS

Inter-modality agreement between CT, ECA-MRI, and EOB-MRI decreases in observations smaller than 20 mm. ECA-MRI has the provided higher sensitivity for the diagnosis of HCC.

Development and validation of a CT-based nomogram for accurate hepatocellular carcinoma detection in high risk patients

Purpose

To establish and validate a CT-based nomogram for accurately detecting HCC in patients at high risk for the disease.

Methods

A total of 223 patients were divided into training (n=161) and validation (n=62) cohorts between January of 2017 and May of 2022. Logistic analysis was performed, and clinical model and radiological model were developed separately. Finally, a nomogram was established based on clinical and radiological features. All models were evaluated using the area under the curve (AUC). DeLong's test was used to evaluate the differences among these models.

Results

In the multivariate analysis, gender (p = 0.014), increased Alpha-fetoprotein (AFP) (p = 0.017), non-rim arterial phase hyperenhancement (APHE) (p = 0.011), washout (p = 0.011), and enhancing capsule (p = 0.001) were the independent differential predictors of HCC. A nomogram was formed with well-fitted calibration curves based on these five factors. The area under the curve (AUC) of the nomogram in the training and validation cohorts was 0.961(95%CI: 0.935~0.986) and 0.979 (95% CI: 0.949~1), respectively. The nomogram outperformed the clinical and the radiological models in training and validation cohorts.

Conclusion

The nomogram incorporating clinical and CT features can be a simple and reliable tool for detecting HCC and achieving risk stratification in patients at high risk for HCC.

Quantitative radiomics and qualitative LI-RADS imaging descriptors for non-invasive assessment of β-catenin mutation status in hepatocellular carcinoma

PURPOSE

Gain-of-function mutations in CTNNB1, gene encoding for β-catenin, are observed in 25-30% of hepatocellular carcinomas (HCCs). Recent studies have shown β-catenin activation to have distinct roles in HCC susceptibility to mTOR inhibitors and resistance to immunotherapy. Our goal was to develop and test a computational imaging-based model to non-invasively assess β-catenin activation in HCC, since liver biopsies are often not done due to risk of complications.

METHODS

This IRB-approved retrospective study included 134 subjects with pathologically proven HCC and available β-catenin activation status, who also had either CT or MR imaging of the liver performed within 1 year of histological assessment. For qualitative descriptors, experienced radiologists assessed the presence of imaging features listed in LI-RADS v2018. For quantitative analysis, a single biopsy proven tumor underwent a 3D segmentation and radiomics features were extracted. We developed prediction models to assess the β-catenin activation in HCC using both qualitative and quantitative descriptors.

RESULTS

There were 41 cases (31%) with β-catenin mutation and 93 cases (69%) without. The model's AUC was 0.70 (95% CI 0.60, 0.79) using radiomics features and 0.64 (0.52, 0.74; p = 0.468) using qualitative descriptors. However, when combined, the AUC increased to 0.88 (0.80, 0.92; p = 0.009). Among the LI-RADS descriptors, the presence of a nodule-in-nodule showed a significant association with β-catenin mutations (p = 0.015). Additionally, 88 radiomics features exhibited a significant association (p < 0.05) with β-catenin mutations.

CONCLUSION

Combination of LI-RADS descriptors and CT/MRI-derived radiomics determine β-catenin activation status in HCC with high confidence, making precision medicine a possibility.

Locoregional Therapies for Hepatocellular Carcinoma prior to Liver Transplant: Comparative Pathologic Necrosis, Radiologic Response, and Recurrence

PURPOSE

To compare pathologic tumor necrosis rates after locoregional therapies (LRTs) for hepatocellular carcinoma (HCC) prior to liver transplantation and evaluate radiologic-pathologic correlation along with posttransplant HCC recurrence.

MATERIALS AND METHODS

Consecutive patients with solitary HCC bridged or downstaged with LRT from 2010 to 2022 were included. LRTs were transarterial chemoembolization (TACE), radioembolization (yttrium-90 [90Y]), ablation, and stereotactic body radiotherapy (SBRT). Upfront combination therapy options were TACE/ablation and TACE/SBRT. Subsequent therapy crossover due to local recurrence was allowed. Posttreatment imaging closest to the time of transplant, explant histopathologic necrosis, and tumor recurrence after transplant were reviewed.

RESULTS

Seventy-three patients met inclusion criteria, of whom 5 (7%) required downstaging. 90Y alone (n = 36) and multimodal therapy (pooled upfront combination and crossover therapy, n = 23) resulted in significantly greater pathologic necrosis compared with TACE alone (n = 14; P = .01). High dose 90Y radiation segmentectomy (≥190 Gy; n = 27) and TACE/ablation (n = 7) showed highest rates of complete pathologic necrosis (CPN)-63% (n = 17) and 71% (n = 5), respectively. Patients with CPN had a mean lesion size of 2.5 cm, compared with 3.2 cm without CPN (P = .04), irrespective of LRT modality. HCC recurrence was more common in patients without CPN (16%, 6/37) than in those with CPN (3%, 1/36; P = .11). Using Liver Imaging Reporting and Data System (LI-RADS), a nonviable imaging response was 75% sensitive and 57% specific for CPN.

CONCLUSIONS

Radiation segmentectomy and multimodal therapy significantly improved CPN rates compared with TACE alone. A LI-RADS treatment response of nonviable did not confidently predict CPN.

LI-RADS threshold growth based on tumor growth rate can improve the diagnosis of hepatocellular carcinoma ≤ 3.0 cm

OBJECTIVE

Despite the revision of threshold growth (TG) in the Liver Imaging Reporting and Data System (LI-RADS) version 2018, the appropriate time period between the two examinations for TG has not been determined. We compared the accuracy of LI-RADS with TG based on tumor growth rate for the diagnosis of hepatocellular carcinoma (HCC) with that of LI-RADS v2018 based on the original TG.

METHODS

Patients who underwent preoperative MRI for focal solid lesions (≤ 3.0 cm) were retrospectively evaluated. Three readers measured the size of each lesion on prior CT/MRI and index MRI, with tumor growth rate defined as the percent change in lesion size per month. In addition to the original TG (≥ 50% size increase within ≤ 6 months), the modified TG based on tumor growth rates ≥ 10%/month (TG-10%), ≥ 20%/month (TG-20%), and ≥ 30%/month (TG-30%) were evaluated. The accuracies of these evaluation methods for LI-RADS category 5 HCC were compared using generalized estimation equations.

RESULTS

A total of 508 lesions from 370 patients were evaluated. Compared with LI-RADS v2018 with the original TG, the accuracy of LI-RADS with TG-10% was significantly higher (85.0% vs. 80.7%, p < .001), whereas the accuracies of LI-RADS with TG-20% (81.3% vs. 80.7%, p = .404) and TG-30% (79.3% vs. 80.7%, p = .052) were not significant. The sensitivity of LI-RADS with TG-10% was higher than that of LI-RADS v2018 (79.0% vs. 72.5%, p < .001), whereas their specificities were not significantly different (96.6% vs. 96.6%, p > .999).

CONCLUSION

TG-10% improved the sensitivity of LI-RADS by detecting additional hepatocellular carcinomas underestimated due to short-term follow-up.

CLINICAL RELEVANCE STATEMENT

Threshold growth based on tumor growth rate can be clinically useful in the diagnosis of hepatocellular carcinoma, by improving the sensitivity of LI-RADS.

KEY POINTS

• The diagnostic accuracy of Liver Imaging Reporting and Data System (LI-RADS) v2018 was not significantly affected by the time interval between prior and index assessments of threshold growth. • In the 334 hepatocellular carcinomas, the frequency of threshold growth was significantly higher using tumor growth rate ≥ 10%/month (TG-10%) than original threshold growth (53.3% vs. 18.0%, p < .001). • Compared with LI-RADS v2018 with the original threshold growth, LI-RADS with TG-10% had significantly higher accuracy (85.0% vs. 80.7%, p < .001) and sensitivity (79.0% vs. 72.5%, p < .001) but a similar specificity (96.6% vs. 96.6%, p > .999).

Suboptimal performance of LI-RADS v2018 on gadoxetic acid-enhanced MRI for detecting hepatocellular carcinoma in liver transplant candidates

OBJECTIVES

To evaluate the diagnostic performance for hepatocellular carcinoma (HCC) detection of the Liver Imaging Reporting and Data System (LI-RADS) version 2018 on gadoxetic acid-enhanced MRI, comparing liver transplant candidates (LT group) with patients who underwent surgical resection (SR group), and to determine significant clinical factors for diagnostic performance of LI-RADS v2018.

METHODS

Patients who underwent gadoxetic acid-enhanced MRI and subsequent SR or LT for HCC were retrospectively included between January 2019 and December 2020. The sensitivity and specificity of LI-RADS LR-5 for HCC were compared between the two groups using generalized estimating equations. The accuracy of patient allocation according to the Milan criteria was calculated for the LT group. Univariable and multivariable logistic regression analyses were performed to determine significant clinical factors associated with the sensitivity of LI-RADS.

RESULTS

Of the 281 patients, 237 were assigned to the SR group, and 44 were assigned to the LT group. The LT group showed significantly lower per-patient (48.5% vs. 79.6%, p < .001) and per-lesion sensitivity (31.0% vs. 75.9%, p < .001) than the SR group, whereas no significant difference in both per-patient (100.0% vs. 91.7%, p > .99) and per-lesion specificities (100.0% vs. 94.1%, p > .99). The accuracy of patient allocation was 50.0%. Sensitivity was significantly lower in patients with a smaller lesion size (p < .001), a larger lesion number (p = .002), and a higher Child-Pugh score (p = .009).

CONCLUSION

LI-RADS v2018 on gadoxetic acid-enhanced MRI might be insufficient in liver transplant candidates and other diagnostic imaging tests should be considered in patients with these significant clinical factors.

CLINICAL RELEVANCE STATEMENT

In liver transplant candidates with a smaller lesion size, a larger lesion number, and a higher Child-Pugh score, imaging tests other than gadoxetic acid-enhanced MRI may be clinically useful to determine the transplant eligibility.

KEY POINTS

• The sensitivity of the Liver Imaging Reporting and Data System (LI-RADS) was lower in liver transplant candidates than in those who underwent surgical resection. • With the use of gadoxetic acid-enhanced MRI, the accuracy of patient allocation for liver transplantation on the basis of the Milan criteria was suboptimal. • The sensitivity of LI-RADS v2018 was significantly associated with lesion size, lesion number, and Child-Pugh classification.

Hepatocellular Carcinoma: Optimal Radiological Evaluation before Liver Transplantation

Liver transplantation (LT) is the recommended curative-intent treatment for patients with early or intermediate-stage hepatocellular carcinoma (HCC) who are ineligible for resection. Imaging plays a central role in staging and for selecting the best LT candidates. This review will discuss recent developments in pre-LT imaging assessment, in particular LT eligibility criteria on imaging, the technical requirements and the diagnostic performance of imaging for the pre-LT diagnosis of HCC including the recent Liver Imaging Reporting and Data System (LI-RADS) criteria, the evaluation of the response to locoregional therapy, as well as the non-invasive prediction of HCC aggressiveness and its impact on the outcome of LT. We will also briefly discuss the role of nuclear medicine in the pre-LT evaluation and the emerging role of artificial intelligence models in patients with HCC.

Therapeutic Approach to Post-Transplant Recurrence of Hepatocellular Carcinoma: Certainties and Open Issues

Hepatocellular carcinoma (HCC) is a growing indication for liver transplantation (LT). Careful candidate selection is a prerequisite to keep post-LT recurrence rates within acceptable percentages. In the pre-LT period, various types of locoregional treatments and/or systemic therapies can be used for bridging or downstaging purposes. In this context, one of the factors limiting the possibility of treatment is the degree of functional liver impairment. In the LT subject, no widely accepted indications are available to guide treatment of disease recurrence and heterogeneity exists between transplant centers. Improved liver function post LT makes multiple therapeutic strategies theoretically feasible, but patient management is complicated by the need to adjust immunosuppressive therapy and to assess potential toxicities and drug-drug interactions. Finally, there is controversy and uncertainty about the use of recently introduced immunotherapeutic drugs, mainly due to the risk of organ rejection. In this paper, we will review the most recent available literature on the management of post-transplant HCC recurrence, discussing evidence and controversies.

Multimodality imaging of hepatocellular carcinoma and intrahepatic cholangiocarcinoma

Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are the two most common primary malignant tumors of the liver. The similarities and variations in imaging characteristics that may aid in distinguishing between these two primary tumors will be discussed and outlined in this review. Knowledge of imaging techniques that are currently available would assist in the differentiation between these primary malignancies.

Hepatocellular carcinoma in patients cured of chronic hepatitis C: Minimal steatosis

BACKGROUND

Successful treatment of hepatitis C reduces liver inflammation and fibrosis; however, patients remain at risk of developing hepatocellular carcinoma (HCC).

AIMS

To identify risk factors for new-onset HCC in patients cured of hepatitis C.

METHODS

Imaging, histological, and clinical data on patients whose first HCC was diagnosed >12 months of post-SVR were analyzed. Histology of 20 nontumor tissues was analyzed in a blinded manner using the Knodel/Ishak/HAI system for necroinflammation and fibrosis/cirrhosis stage and the Brunt system for steatosis/steatohepatitis. Factors associated with post-SVR HCC were identified by comparison with HALT-C participants who did not develop post-SVR HCC.

RESULTS

Hepatocellular carcinoma was diagnosed in 54 patients (45 M/9F), a median of 6 years of post-SVR [interquartile range (IQR) =1.4-10y] at a median age of 61 years (IQR, 59-67). Approximately one-third lacked cirrhosis, and only 11% had steatosis on imaging. The majority (60%) had no steatosis/steatohepatitis in histopathology. The median HAI score was 3 (1.25-4), indicating mild necroinflammation. In a multivariable logistic regression model, post-SVR HCC was positively associated with non-Caucasian race (p = 0.03), smoking (p = 0.03), age > 60 years at HCC diagnosis (p = 0.03), albumin<3.5 g/dL (p = 0.02), AST/ALT>1 (p = 0.05), and platelets <100 × 103 cells/μL (p < 0.001). Alpha fetoprotein ≥4.75 ng/mL had 90% specificity and 71% sensitivity for HCC occurrence. Noncirrhotic patients had larger tumors (p = 0.002) and a higher prevalence of vascular invasion (p = 0.016) than cirrhotic patients.

CONCLUSIONS

One-third of patients with post-SVR HCC did not have liver cirrhosis; most had no steatosis/steatohepatitis. Hepatocellular carcinomas were more advanced in noncirrhotic patients. Results support AFP as a promising marker of post-SVR HCC risk.

Improved diagnosis of histological capsule in hepatocallular carcinoma by using nonenhancing capsule appearance in addition to enhancing capsule appearance in gadoxetic acid-enhanced MRI

To assess the value of nonenhancing capsule by adding to enhancing capsule in gadoxetic acid-enhanced MRI (EOB-MRI) in comparison with contrast-enhanced CT (CE-CT) for diagnosing histological capsule in hepatocellular carcinoma (HCC). One-hundred fifty-one patients with HCC who underwent both CE-CT and EOB-MRI were retrospectively reviewed. Liver Imaging-Reporting and Data System (LI-RADS) v2018 imaging features, including enhancing and nonenhancing capsule were evaluated by two readers in CE-CT and EOB-MRI. Frequencies of each imaging feature were compared between CE-CT and EOB-MRI. The area under the receiver operating characteristic (AUC) curve for the diagnosis of histological capsule was compared across the following three imaging criteria: (1) enhancing capsule in CE-CT, (2) enhancing capsule in EOB-MRI, and (3) enhancing/nonenhancing capsule in EOB-MRI. Enhancing capsule in EOB-MRI was significantly less frequently depicted than that in CE-CT (p < 0.001 and = 0.016 for reader 1 and 2). Enhancing/nonenhancing capsule in EOB-MRI achieved a similar frequency of enhancing in CE-CT (p = 0.590 and 0.465 for reader 1 and 2). Adding nonenhancing capsule to enhancing capsule in EOB-MRI significantly increased AUCs (p < 0.001 for both readers) and achieved similar AUCs compared with enhancing capsule in CE-CT (p = 0.470 and 0.666 for reader 1 and 2). Adding nonenhancing capsule to the definition of capsule appearance can improve the diagnosis of capsule in EOB-MRI for the diagnosis of histological capsule in HCC and decrease discordance of capsule appearance between EOB-MRI and CE-CT.

Value of threshold growth as a major diagnostic feature of hepatocellular carcinoma in LI-RADS

BACKGROUND & AIMS

The Liver Reporting and Data System (LI-RADS) version 2018 simplified the definition of threshold growth to '≥50% size increase in a mass in ≤6 months'. However, the diagnostic value of threshold growth for hepatocellular carcinoma (HCC) remained unclear. We evaluated the value of threshold growth, as defined by LI-RADS v2018, in diagnosing HCCs.

METHODS

Patients who underwent preoperative gadoxetate disodium-enhanced MRI because of the presence of LI-RADS category 2, 3, or 4 rather than category 5 on prior CT/MRI between January 2017 and December 2020 were retrospectively evaluated. Pathologic or clinical diagnoses were used as reference standards. Imaging features were evaluated by three readers according to LI-RADS v2018. The frequency and diagnostic odds ratio of threshold growth were calculated. The diagnostic performance of LI-RADS category 5 was separately evaluated when threshold growth was and was not considered a major feature, and results were compared using generalized estimation equations. Subgroups of patients who underwent CT/MRI during the previous 3-6 months were analyzed.

RESULTS

Analysis of 340 observations in 243 patients found that the frequency of threshold growth was 18.8% and it gradually increased over time. Threshold growth was significantly associated with HCC (diagnostic odds ratio 5.2; 95% CI 2.1-12.7; p <0.001). Use of threshold growth as a major feature significantly increased sensitivity in both the overall (66.4% vs. 57.3%, p <0.001) and subgroup (73.4% vs. 58.2%, p <0.001) cohorts, but had no effect on specificity in either the overall (97.5% vs. 98.3%, p = 0.319) or subgroup (95.9% vs. 98.0%, p = 0.323) cohorts.

CONCLUSION

The revised threshold growth of LI-RADS v2018 was significantly associated with HCC. Use of threshold growth as a major diagnostic feature of HCC can improve the sensitivity of LI-RADS v2018.

IMPACT AND IMPLICATIONS

We found that the revised threshold growth in the Liver Imaging Reporting and Data System version 2018 (LI-RADS v2018) was a significant predictor of hepatocellular carcinoma (HCC). The use of threshold growth as a major imaging feature of HCC significantly increased the sensitivity of LI-RADS v2018, especially small HCCs (≤3.0 cm), compared with its non-use. Because these small HCCs are eligible for curative treatments, the additional detection of small HCCs is clinically meaningful.

Preoperative sintilimab plus transarterial chemoembolization for hepatocellular carcinoma exceeding the Milan criteria: A phase II trial

BACKGROUND AND AIMS

Many patients with HCC of Barcelona Clinic Liver Cancer (BCLC) stage A exceeding the Milan criteria, or of BCLC stage B, can undergo resection after successful preoperative therapy, but an optimal approach has not been identified. We investigated preoperative drug-eluting bead transarterial chemoembolization (DEB-TACE) plus sintilimab, in this setting.

APPROACH AND RESULTS

In this prospective, phase II study (NCT04174781), adults with HCC of BCLC stage A exceeding the Milan criteria, or BCLC stage B, and ineligible for surgical resection, received sintilimab 200 mg and DEB-TACE. The primary endpoint was progression-free survival by modified RECIST. Secondary endpoints included objective response rate, pathologic response rate, and safety. At the data cutoff (July 2022), among 60 patients, the objective response rate was 62% (37/60) and 51 patients had undergone surgery. After a median follow-up of 26.0 months (range, 3.4-31.8), the median progression-free survival was 30.5 months (95% CI: 16.1-not reached). Among patients undergoing surgery, median progression-free survival was not reached and the 12-month progression-free survival rate was 76% (95% CI: 67-91). A pathologic complete response was achieved in 14% (7/51) of these patients. All patients experienced at least one adverse event, but these were generally manageable. Exploratory analyses showed an association between cytokeratin, V-domain Ig-containing Suppressor of T-cell Activation, CD68, CD169, and cluster 13 fibroblasts and recurrence after surgery.

CONCLUSIONS

Sintilimab plus DEB-TACE before surgery showed good efficacy and safety in patients with HCC of BCLC stage A exceeding the Milan criteria or BCLC stage B.

Prospective evaluation of Gadoxetate-enhanced magnetic resonance imaging and computed tomography for hepatocellular carcinoma detection and transplant eligibility assessment with explant histopathology correlation

BACKGROUND

We aimed to prospectively compare the diagnostic performance of gadoxetic acid-enhanced MRI (EOB-MRI) and contrast-enhanced Computed Tomography (CECT) for hepatocellular carcinoma (HCC) detection and liver transplant (LT) eligibility assessment in cirrhotic patients with explant histopathology correlation.

METHODS

In this prospective, single-institution ethics-approved study, 101 cirrhotic patients were enrolled consecutively from the pre-LT clinic with written informed consent. Patients underwent CECT and EOB-MRI alternately every 3 months until LT or study exclusion. Two blinded radiologists independently scored hepatic lesions on CECT and EOB-MRI utilizing the liver imaging reporting and data system (LI-RADS) version 2018. Liver explant histopathology was the reference standard. Pre-LT eligibility accuracies with EOB-MRI and CECT as per Milan criteria (MC) were assessed in reference to post-LT explant histopathology. Lesion-level and patient-level statistical analyses were performed.

RESULTS

Sixty patients (49 men; age 33-72 years) underwent LT successfully. One hundred four non-treated HCC and 42 viable HCC in previously treated HCC were identified at explant histopathology. For LR-4/5 category lesions, EOB-MRI had a higher pooled sensitivity (86.7% versus 75.3%, p <  0.001) but lower specificity (84.6% versus 100%, p <  0.001) compared to CECT. EOB-MRI had a sensitivity twice that of CECT (65.9% versus 32.2%, p <  0.001) when all HCC identified at explant histopathology were included in the analysis instead of imaging visible lesions only. Disregarding the hepatobiliary phase resulted in a significant drop in EOB-MRI performance (86.7 to 72.8%, p <  0.001). EOB-MRI had significantly lower pooled sensitivity and specificity versus CECT in the LR5 category with lesion size < 2 cm (50% versus 79%, p = 0.002 and 88.9% versus 100%, p = 0.002). EOB-MRI had higher sensitivity (84.8% versus 75%, p <  0.037) compared to CECT for detecting < 2 cm viable HCC in treated lesions. Accuracies of LT eligibility assessment were comparable between EOB-MRI (90-91.7%, p = 0.156) and CECT (90-95%, p = 0.158).

CONCLUSION

EOB-MRI had superior sensitivity for HCC detection; however, with lower specificity compared to CECT in LR4/5 category lesions while it was inferior to CECT in the LR5 category under 2 cm. The accuracy for LT eligibility assessment based on MC was not significantly different between EOB-MRI and CECT.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03342677 , Registered: November 17, 2017.

A Multi-centre, Single Arm, Non-randomized, Prospective European Trial to Evaluate the Safety and Efficacy of the HistoSonics System in the Treatment of Primary and Metastatic Liver Cancers (#HOPE4LIVER)

PURPOSE

Image-guided thermal ablation are established treatment options for non-surgical patients with primary and metastatic liver cancers. However, there are limitations with nonuniformity of cancer tissue destruction, heat sink effect and the risk of thermal ablative injury. The current non-thermal ablative techniques have high risk of local recurrence and are not widely adopted. Histotripsy is a treatment technology that destroys targeted tissue under ultrasound visualization via mechanical destruction through the precise application of acoustic cavitation and can offer the potential of non-invasive, non-thermal and non-ionizing radiation cancer treatment. The aim of this multi-centre non-randomized phase I/II trial is to assess the initial safety and efficacy of the prototype investigational 'System' in the treatment of primary and metastatic liver cancers.

METHODS/DESIGN

All non-surgical patients with primary/metastatic liver cancers having had previous liver directed therapy, radiation therapy or image-guided ablation may be offered image-guided Histotripsy as per trial protocol. The co-primary endpoints are technical success and procedural safety. Technical success is determined, at ≤ 36 h post procedure, by evaluating the histotripsy treatment size and coverage. The procedural safety is defined by procedure related major complications, defined as Common Terminology Criteria for Adverse Events (CTCAE version 5) grade 3 or higher toxicities, up to 30 days post procedure. This phase I/II trial has intended to recruit up to 45 patients to show safety and efficacy of image-guided histotripsy in liver cancers.

TRAIL REGISTRATION

Clinicaltrials.gov identifier-NCT04573881; NIHR CRN CPMS-ID 47572.

Outcomes of LI-RADS US-2 Subthreshold Observations Detected on Surveillance Ultrasound

BACKGROUND. Ultrasound LI-RADS version 2017 recommends that patients with US-2 subthreshold observations undergo repeat surveillance ultrasound in 3-6 months and return to routine surveillance if the observation shows no growth for 2 years. However, outcomes of US-2 observations are unknown. OBJECTIVE. The purpose of this article was to determine imaging outcomes of US-2 observations detected on surveillance ultrasound examinations. METHODS. This retrospective study included 175 patients (median age, 59 years; 70 women, 105 men) at high risk for hepatocellular carcinoma (HCC) with US-2 observations (i.e., subcentimeter observations) on surveillance ultrasound. Observations were classified on follow-up ultrasound performed 2 or more years later as showing no correlate, stable (if remaining subcentimeter), or progressed (if measuring ≥ 10 mm, meeting US-3 criteria). Observations were classified on follow-up multiphasic CT or MRI (stratified as < 2-year vs ≥ 2-year follow-up) as showing no correlate or, if showing a correlate, using CT/MRI LI-RADS version 2018. RESULTS. A total of 111 patients had follow-up ultrasound after 2 or more years and 106 had follow-up CT or MRI (79 before 2 years, 27 after 2 years). On the basis of final follow-up examinations, 173 of 175 observations were stable on follow-up ultrasound 2 or more years later (n = 68); showed no correlate on follow-up ultrasound, CT, or MRI (n = 88); or were classified as LR-1 or LR-2 on CT or MRI (n = 17). The remaining 2 of 175 observations were LR-3 on CT or MRI. No observations progressed to US-3 on follow-up ultrasound or were classified as LR-4 or greater on CT or MRI. A correlate was observed in 25 of the 106 follow-up CT or MRI examinations (LR-1 or LR-2 in 23; LR-3 in two). Eight patients developed HCC at a median of 2.0 years after initial US-2 observation detection; all HCCs were in separate locations from the baseline observations and were preceded by a surveillance ultrasound that could not reidentify the baseline observation. In three patients who underwent liver transplant, the explant showed no dysplastic nodule or HCC. CONCLUSION. US-2 subthreshold observations are unlikely to progress or become HCC and commonly have no correlate on follow-up imaging. CLINICAL IMPACT. Because of the low progression rate of US-2 subthreshold observations, it is unclear if an extended period of intensive surveillance, as recommended by multiple professional societies, is warranted.

Liver resection of hepatocellular carcinoma in HIV-HCV co-infected patients: a retrospective case series

Introduction

Despite the effectiveness of new therapies and awareness campaigns, the number of seropositive patients is increasing every year. Recently, other causes of death, not directly related to HIV, have emerged, such as chronic liver disease. The risk of hepatocellular carcinoma (HCC) is seven times greater in HIV patients than in noninfected patients, and it is especially attributable to HCV infection. The aim of our study was to evaluate clinical outcomes of HCC in HIV-HCV co-infected patients after liver resection (LR).

Materials and methods

The current study was conducted on a prospective database and reviewed retrospectively. All consecutive patients with HCC treated by LR from January 2013 to March 2019 at the Luigi Sacco University Hospital in Milan were enrolled. We included patients older than 18 years of age with HCV-related HCC, and in this set of patients, we identified two groups based on the presence of HIV infection.

Results

We identified 16 patients with HCV infection and precisely five with HIV-HCV co-infection and eleven with HCV infection alone. All HIV patients were male against 72.7% in the non-HIV group (p = 0.509). All patients had optimal HIV virologic control and a normal CD4 T-cell count. The mean diagnosis-to-treatment interval was statistically different between the two groups (HIV versus non-HIV: 1.2 ± 0.55 months versus 2.39 ± 1.09 months, p = 0.039).

No other significant differences were found between HIV-HCV co-infected patients and HCV-infected patients. Long-term outcomes in terms of OS and RFS were similar between the two groups.

Conclusions

With a multidisciplinary approach and intensive support, LR can be a safe and efficacious procedure in HIV-HCV patients. For these reasons, we should not exclude potential patients merely on the basis of their HIV seropositivity.

Contrast-Enhanced Ultrasound Using Perfluorobutane: Impact of Proposed Modified LI-RADS Criteria on Hepatocellular Carcinoma Detection

BACKGROUND. Contrast-enhanced ultrasound (CEUS) LI-RADS version 2017 (v2017) applies only to CEUS examinations performed using pure blood pool agents, noting that future versions will address combined blood pool and Kupffer cell agents such as perfluorobutane. Such agents may improve hepatocellular carcinoma (HCC) detection by visualization of a defect in the Kupffer phase (obtained ≥ 10 minutes after injection). OBJECTIVE. The purpose of our study was to compare the diagnostic performance of the LR-5 category for HCC detection in at-risk patients between CEUS LI-RADS v2017 and proposed modified criteria for CEUS examinations performed using perfluorobutane. METHODS. This retrospective study included 293 patients at risk for HCC (259 men, 34 women; mean age, 55 ± 12 [SD] years) who underwent CEUS using perfluorobutane from March 1, 2020, to October 30, 2020, showing a total of 304 observations (274 HCC, 14 non-HCC malignancy, and 16 benign lesions). Two readers independently assessed examinations and assigned categories using both CEUS LI-RADS v2017 and the proposed modified criteria. In the modified criteria, observations 10 mm or greater with not rim arterial phase hyperenhancement (APHE), no washout, and a Kupffer defect were upgraded from LR-4 to LR-5, and observations 10 mm or greater with not rim APHE, early washout, and a mild Kupffer defect were reassigned from LR-M to LR-5. Interreader agreement was assessed, and consensus interpretations were reached. Diagnostic performance was evaluated. RESULTS. Interreader agreement for LI-RADS category assignments, expressed using kappa coefficients, was 0.839 for CEUS LI-RADS v2017 and 0.854 for the modified criteria. Modified criteria upgraded 35 observations from LR-4 to LR-5 on the basis of a Kupffer defect, of which 34 were HCC and one was benign. Modified criteria reassigned 22 observations from LR-M to LR-5 on the basis of a mild Kupffer defect, of which all were HCC. LR-5 using modified criteria, compared with CEUS LI-RADS v2017, had significantly increased sensitivity (89% vs 69%, p < .001), a nonsignificant decrease in specificity (83% vs 87%, p > .99), and significantly increased accuracy (89% vs 71%, p < .001) for HCC. CONCLUSION. When using perfluorobutane for CEUS in at-risk patients, modified criteria incorporating Kupffer defects significantly improve sensitivity without significant loss of specificity in HCC detection. CLINICAL IMPACT. Future CEUS LI-RADS updates seeking to address the use of combined blood pool and Kupffer cell agents should consider adoption of the explored criteria.

Cancer tracking system improves timeliness of liver cancer care at a Veterans Hospital: A comparison of cohorts before and after implementation of an automated care coordination tool

INTRODUCTION

Hepatocellular carcinoma (HCC) requires complex care coordination. Patient safety may be compromised with untimely follow-up of abnormal liver imaging. This study evaluated whether an electronic case-finding and tracking system improved timeliness of HCC care.

METHODS

An electronic medical record-linked abnormal imaging identification and tracking system was implemented at a Veterans Affairs Hospital. This system reviews all liver radiology reports, generates a queue of abnormal cases for review, and maintains a queue of cancer care events with due dates and automated reminders. This is a pre-/post-intervention cohort study to evaluate whether implementation of this tracking system reduced time between HCC diagnosis and treatment and time between first liver image suspicious for HCC, specialty care, diagnosis, and treatment at a Veterans Hospital. Patients diagnosed with HCC in the 37 months before tracking system implementation were compared to patients diagnosed with HCC in the 71 months after its implementation. Linear regression was used to calculate mean change in relevant intervals of care adjusted for age, race, ethnicity, BCLC stage, and indication for first suspicious image.

RESULTS

There were 60 patients pre-intervention and 127 post-intervention. In the post-intervention group, adjusted mean time from diagnosis to treatment was 36 days shorter (p = 0.007), time from imaging to diagnosis 51 days shorter (p = 0.21), and time from imaging to treatment 87 days shorter (p = 0.05). Patients whose imaging was performed for HCC screening had the greatest improvement in time from diagnosis to treatment (63 days, p = 0.02) and from first suspicious image to treatment (179 days, p = 0.03). The post-intervention group also had a greater proportion of HCC diagnosed at earlier BCLC stages (p<0.03).

CONCLUSIONS

The tracking system improved timeliness of HCC diagnosis and treatment and may be useful for improving HCC care delivery, including in health systems already implementing HCC screening.

Interrater reliability and agreement of the liver imaging reporting and data system (LI-RADS) v2018 for the evaluation of hepatic lesions

Purpose

The liver imaging reporting and data system (LI-RADS) is a structured reporting system that categorizes hepatic observations according to major imaging features and lesion size, with an optional ancillary features contribution. This study aimed to evaluate inter-reader agreement of dynamic magnetic resonance imaging (MRI) using LI-RADS v2018 lexicon.

Material and methods

Forty-nine patients with 69 hepatic observations were included in our study. The major and ancillary features of each hepatic observation were evaluated by 2 radiologists using LI-RADS v2018, and the interreader agreement was allocated.

Results

The inter-reader agreement of major LI-RADS features was substantial; κ of non-rim arterial hyperenhancement, non-peripheral washout appearance, and enhancing capsule was 0.796, 0.799, and 0.772 (p < 0.001), respectively. The agreement of the final LI-RADS category was substantial with κ = 0.651 (p < 0.001), and weighted κ = 0.786 (p < 0.001). The inter-reader agreement of the ancillary features was substantial to almost perfect (k range from 0.718 to 1; p < 0.001). An almost perfect correlation was noted for the hepatic lesion size measurement with ICC = 0.977 (p < 0.001).

Conclusions

The major and ancillary features of the LI-RADS v2018, as well as the final category and lesions size, have substantial to almost perfect inter-reader agreement.

Performance of LI-RADS Version 2018 on CT for Determining Eligibility for Liver Transplant According to Milan Criteria in Patients at High Risk for Hepatocellular Carcinoma

BACKGROUND. LI-RADS has been investigated primarily in terms of detection of hepatocellular carcinoma (HCC), with less attention given to its performance, particularly on CT, in determining eligibility for liver transplant (LT). OBJECTIVE. The purpose of our study was to assess the performance of LI-RADS version 2018 (v2018) on CT for the diagnosis of HCC and determination of LT eligibility according to the Milan criteria (MC). METHODS. This retrospective study included 136 patients (110 men, 26 women; mean age, 53.9 ± 8.1 [SD] years) at high-risk for HCC who underwent liver protocol CT within 3 months before LT between January 2010 and December 2018. Two radiologists independently reviewed CT examinations using LI-RADS v2018; Organ Procurement and Transplantation Network (OPTN) classes were constructed from the LI-RADS interpretations. Histopathologic analysis of liver explants served as the reference standard for determining the presence of HCC and LT eligibility based on MC. Diagnostic performance was evaluated. Overall survival (OS) was assessed based on medical record review. RESULTS. Based on histopathologic evaluation of liver explants in the 136 patients, 27 patients had no malignancy, 77 were eligible for LT due to HCC within MC, and 32 were unsuitable for LT (i.e., HCC beyond MC in 16 patients, HCC with macrovascular invasion in 12, non-HCC malignancy in four). LR-5 exhibited per-lesion sensitivity and PPV for HCC of 55.9% and 92.8%, respectively, for reader 1 and 39.8% and 86.5% for reader 2. When considering LR-5 observations to represent HCC in assessing MC, LI-RADS had accuracy for determining LT eligibility of 92.7% for reader 1 and 85.3% for reader 2; OPTN criteria had accuracy for determining LT eligibility of 89.0% for reader 1 and 84.4% for reader 2. Five-year OS for patients within MC versus 5-year OS for patients unsuitable for LT was 92.2 months versus 56.0 months for LI-RADS, 92.6 months versus 47.6 months for OPTN criteria, and 93.3 months versus 55.1 months for histopathologic assessment of liver explants. CONCLUSION. LI-RADS v2018, as evaluated on CT in high-risk patients, shows high PPV for HCC detection and high accuracy for determining LT eligibility based on MC. LT eligibility based on preoperative LI-RADS evaluation is associated with post-LT survival. CLINICAL IMPACT. These findings support the use of LI-RADS on CT in assessing eligibility in patients who are candidates for LT.

Interindividual Comparison of Frequency-Selective Nonlinear Blending to Conventional CT for Detection of Focal Liver Lesions Using MRI as the Reference Standard

BACKGROUND. Diagnosing liver lesions is challenging. CT is used for primary diagnosis, but its contrast resolution is limited. Investigating methods to improve detection of liver lesions is important. OBJECTIVE. The purpose of this study was to evaluate the effect of frequency-selective nonlinear blending on the detectability of liver lesions on CT. METHODS. A retrospective search yielded 109 patients with 356 malignant and benign liver lesions (191 principally diagnosed, 165 incidental findings) who underwent contrast-enhanced CT (CECT) in the portal venous phase and liver MRI between January 2012 and December 2017. Nonlinear blending was applied to CECT examinations, and three blinded readers independently rated the quality (5-point Likert scale) of randomly presented images. Focal lesions (n = 356) were evaluated for lesion identification and categorization to assess sensitivity. For 191 lesions (primary diagnosis), two readers evaluated CECT and nonlinear blending CT to compare lesion size and the accuracy of subjective measurements. A fourth reader performed ROI measurements for calculation of contrast-to-noise ratio (CNR), and a fifth reader reviewed MRI as the standard of reference. Statistics included interobserver agreement, quantitative comparisons of CNR, lesion size, and subjective image analyses of image quality and sensitivity for detecting liver lesions. RESULTS. Three readers rated the image quality of nonlinear blending CT (rating, 4; 10th-90th percentiles, 4-5) higher than that of CECT (rating, 2; 10th-90th percentiles, 1-3) (p < .001). CECT had good interreader agreement (interclass correlation coefficient [ICC], 0.81; 95% CI, 0.76-0.85), as did nonlinear blending CT (ICC, 0.75; 95% CI, 0.69-0.79). The median CNR of liver lesions increased with nonlinear blending (CECT, 4.18 [10th-90th percentiles, 1.67-9.06]; nonlinear blending CT, 12.49 [10th-90th percentiles, 6.18-23.39]; p < .001). Bland-Altman analysis of lesion size showed a reduction in underestimation from 2.5 (SD, 9.2) mm (95% CI, 1.2-3.9 mm) with CECT to 0.1 (SD, 3.9) mm (95% CI, -0.68 to 0.46 mm) for nonlinear blending CT (concordance correlation coefficient, 0.99). Sensitivity for detecting liver lesions increased to 86% for nonlinear blending CT. The sensitivity of CECT was 76%. CONCLUSION. Frequency-selective nonlinear blending in CECT increases image quality and CNR, increases the precision of size measurement, and increases sensitivity for detecting liver lesions. CLINICAL IMPACT. Use of nonlinear blending CT improves liver lesion detection and increases the accuracy of lesion size measurement, which is important when local ablation or liver transplant is being considered.

Hepatobiliary phase images of gadoxetic acid-enhanced MRI may improve accuracy of predicting the size of hepatocellular carcinoma at pathology

BACKGROUND

Gadoxetic acid-enhanced magnetic resonance imaging (MRI) has been widely used in clinical practice. However, scientific evidence is lacking for recommending a particular sequence for measuring tumor size.

PURPOSE

To retrospectively compare the size of hepatocellular carcinoma (HCC) measured on different gadoxetic acid-enhanced MRI sequences using pathology as a reference.

MATERIAL AND METHODS

A total of 217 patients with single HCC who underwent gadoxetic acid-enhanced MRI before surgery were included. The size of the HCC was measured by two abdominal radiologists independently on the following sequences: T1-weighted; T2-weighted; b-500 diffusion-weighted imaging (DWI); and arterial, portal venous, transitional, and hepatobiliary phases. Tumor size measured on MRI was compared with pathological size by using Pearson correlation coefficient, independent-sample t test, and Bland-Altman plot. Agreement between two readers was evaluated with intraclass correlation coefficient (ICC).

RESULTS

Correlation between the MR images and pathology was high for both readers (0.899-0.955). Absolute error between MRI and pathologic assessment was lowest on hepatobiliary phase images for both readers (reader 1, 2.8±4.2 mm; reader 2, 3.2±3.4 mm) and highest on arterial phase images for reader 1 (4.9±4.4 mm) and DWI phase images for reader 2 (5.1±4.9 mm). Absolute errors were significantly different for hepatobiliary phase compared with other sequences for both readers (reader 1, P≤0.012; reader 2, P≤0.037). Inter-reader agreements for all sequence measurements were strong (0.971-0.997).

CONCLUSION

The performance of gadoxetic acid-enhanced MRI sequences varied with HCC size, and the hepatobiliary phase may be optimal among these sequences.

The Promise of Magnetic Resonance Imaging in Radiation Oncology Practice in the Management of Brain, Prostate, and GI Malignancies

Magnetic resonance imaging (MRI) has a key role to play at multiple steps of the radiotherapy (RT) treatment planning and delivery process. Development of high-precision RT techniques such as intensity-modulated RT, stereotactic ablative RT, and particle beam therapy has enabled oncologists to escalate RT dose to the target while restricting doses to organs at risk (OAR). MRI plays a critical role in target volume delineation in various disease sites, thus ensuring that these high-precision techniques can be safely implemented. Accurate identification of gross disease has also enabled selective dose escalation as a means to widen the therapeutic index. Morphological and functional MRI sequences have also facilitated an understanding of temporal changes in target volumes and OAR during a course of RT, allowing for midtreatment volumetric and biological adaptation. The latest advancement in linear accelerator technology has led to the incorporation of an MRI scanner in the treatment unit. MRI-guided RT provides the opportunity for MRI-only workflow along with online adaptation for either target or OAR or both. MRI plays a key role in post-treatment response evaluation and is an important tool for guiding decision making. In this review, we briefly discuss the RT-related applications of MRI in the management of brain, prostate, and GI malignancies.

Multimodality Imaging after Liver Transplant: Top 10 Important Complications

Patients who have undergone liver transplant are now regularly seen in day-to-day radiology practice. All surgical techniques for liver transplant require arterial, portal venous, hepatic venous and caval, and biliary anastomoses. This review is focused on the 10 "not to be missed" complications of liver transplant that affect the health and life of the graft and graft recipient. Arterial complications are the most common and devastating. Early hepatic artery thrombosis may be catastrophic because the biliary tree is solely dependent on the hepatic artery after transplant and collateral vessels have not yet formed. In contrast, delayed hepatic artery thrombosis may be more insidious as collateral arteries develop. US findings of delayed hepatic artery thrombosis may be similar to those of hepatic artery stenosis and celiac artery stenosis. Splenic artery steal syndrome is an increasingly recognized cause of graft ischemia. Venous complications are much less common. Hepatic venous and caval complications are notable for their increased incidence in living-donor and pediatric transplants. Biliary complications often result from arterial ischemia. Biliary cast syndrome is a notable example in which ischemic biliary mucosa sloughs into and obstructs the duct lumens. Neoplasms also may occur within the hepatic graft and may be due to recurrent malignancy, posttransplant lymphoproliferative disorder, or metastases. US is the initial imaging modality of choice, particularly in the acute postoperative setting. Further evaluation with contrast-enhanced US, CT, or MRI; catheter angiography; endoscopic retrograde cholangiopancreatography; and/or nuclear medicine studies is performed as needed. An invited commentary by Bhargava is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

LI-RADS Treatment Response Algorithm: Performance and Diagnostic Accuracy With Radiologic-Pathologic Explant Correlation in Patients With SBRT-Treated Hepatocellular Carcinoma

PURPOSE

Our purpose was to evaluate the accuracy of LI-RADS Treatment Response Algorithm (LR-TRA) for assessing the viability of hepatocellular carcinoma (HCC) treated with stereotactic body radiation therapy (SBRT), using explant pathology as the gold standard.

METHODS AND MATERIALS

This retrospective study included patients who underwent SBRT for locoregional treatment of HCC between 2008 and 2019 with subsequent liver transplantation. Five radiologists independently assessed all treated lesions by using the LR-TRA. Imaging and posttransplant histopathology were compared. Lesions were categorized as either completely (100%) or incompletely (<100%) necrotic, and performance characteristics and predictive values for the LR-TR viable and nonviable categories were calculated for each reader. Interreader reliability was calculated using the Fleiss kappa test.

RESULTS

A total of 40 treated lesions in 26 patients (median age, 63 years [interquartile range, 59.4-65.5]; 23 men) were included. For lesions treated with SBRT, sensitivity for incomplete tumor necrosis across readers ranged between 71% and 86%, specificity between 85% and 96%, and positive predictive value between 86% and 92%, when the LR-TR equivocal category was treated as nonviable, accounting for subject clustering. When the LR-TR equivocal category was treated as viable, sensitivity of complete tumor necrosis for lesions treated with SBRT ranged from 88% to 96%, specificity from 71% to 93%, and negative predictive value from 85% to 96%. Interreader reliability was fair (k = 0.22; 95% confidence interval, 0.13-0.33). Although a loss of arterial phase hyperenhancement (APHE) was highly correlated with pathologically nonviable tumor on explant, almost half of the patients with APHE had pathologically nonviable tumor on explant.

CONCLUSIONS

LR-TRA v2018 performs well for predicting complete and incomplete necrosis in HCC treated with SBRT. In contrast to other locoregional therapies, the presence of APHE after SBRT does not always indicate viable tumor and suggests that observation may be an appropriate strategy for these patients.

Comparison of gadoxetate disodium-enhanced MRI sequences for measuring hepatic observation size and its implication of LI-RADS classification

PURPOSE

We aimed to determine the optimal image sequence for measurement of hepatic observations on gadoxetate disodium-enhanced MRI in comparison with pathologic measurement, and to evaluate its clinical impact on the Liver Imaging Reporting and Data System (LI-RADS) v2018 classification.

METHODS

Two hundred and fifty-three patients (279 hepatic observations) who underwent gadoxetate disodium-enhanced MRI and subsequent hepatectomy were retrospectively included. Two radiologists independently evaluated the visualization score (five-point scale) and size of each observation on six MRI sequences (T1-weighted, T2-weighted, arterial-phase, portal venous-phase, transitional-phase [TP], and hepatobiliary-phase [HBP] images) and assigned a LI-RADS category. Correlations between MRI and pathologic measurements were evaluated using Pearson correlation coefficients. A repeated measures analysis of variance with Bonferroni post hoc comparison tests was used to compare the visualization scores and absolute differences between MRI sequences and pathologic measurements. The LI-RADS classification according the size measurement of each MRI sequence was compared using Cochran's Q test with a post hoc McNemar's test.

RESULTS

Of the MRI sequences, HBP had the highest visualization score (4.1 ± 0.6) and correlation coefficient (r = 0.965). The absolute difference between MRI and pathologic measurement was lowest on TP (2.3 mm ± 2.2), followed by HBP (2.4 mm ± 2.1). In the LI-RADS classifications, HBP did not have any non-visible observations. Regarding LR-3, LR-4, and LR-5, there was no significantly different LI-RADS classification among the six MRI sequences (p ≥ 0.122).

CONCLUSION

Hepatobiliary-phase images are clinically useful for measuring hepatic observations on gadoxetate disodium-enhanced MRI, especially regarding visibility and correlation with pathologic findings.

Changing opportunities for liver transplant for patients with hepatocellular carcinoma

INTRODUCTION

Aim was to study the early impact of acuity circle-based allocation implementation system, on liver transplantation for hepatocellular carcinoma (HCC) patients.

METHODS

We assessed characteristics of HCC and non-HCC deceased donor orthotopic liver transplants (OLT) in the year before (2/2019-2/2020) and after (3/2020-2/2021) introduction of the acuity circle policy using the Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) database.

RESULTS

Total OLTs reduced from 6699 in the pre-acuity circle era to 6660 in the post-acuity circle era (-0.6%); this decrease is mostly driven by a decrease in HCC transplants (1529 to 1351; -11.6%). Six out of 11 regions had a reduction in the absolute number and percentage of HCC transplants with significant reductions in regions 2 (-37.8%, p<0.001) and 4 (-28.3%, p = 0.001).

DISCUSSION

The introduction of median model for end-stage liver disease (MELD) at transplant minus 3 (MMaT-3) exception points, has created differential opportunities for HCC patients, in low-MELD as opposed to high-MELD areas, despite having the same disease. This effect has become more prominent following the implementation of acuity circle-based allocation system. Ongoing investigation of these trends is needed to ensure that HCC patients are not disparately disadvantaged due to their location. This article is protected by copyright. All rights reserved.

From LI-RADS Classification to HCC Pathology: A Retrospective Single-Institution Analysis of Clinico-Pathological Features Affecting Oncological Outcomes after Curative Surgery

Background: The latest Liver Imaging Reporting and Data System (LI-RADS) classification by the American College of Radiology has been recently endorsed in the American Association for the Study of Liver Disease (AASLD) guidelines for Hepatocellular carcinoma (HCC) management. Although the LI-RADS protocol has been developed as a diagnostic algorithm, there is some evidence concerning a possible correlation between different LI-RADS classes and specific pathological features of HCC. We aimed to investigate such radiological/pathological correlation and the possible prognostic implication of LI-RADS on a retrospective cohort of HCC patients undergoing surgical resection. Methods: We performed a retrospective analysis of the pathological characteristics of resected HCC, exploring their distribution among different LI-RADS classes and analyzing the risk factors for recurrence-free, overall and cancer-specific survival Results: LI-RADS-5 (LR-5) nodules showed a higher prevalence of microvascular invasion (MVI), satellitosis and capsule infiltration, as well as higher median values of alpha-fetoprotein (αFP) compared to LI-RADS-3/4 (LR-3/4) nodules. MVI, αFP, satellitosis and margin-positive (R1) resection resulted as independent risk factors for recurrence-free survival, while LI-RADS class did not exert any significant impact. Focusing on overall survival, we identified patient age, Eastern Cooperative Oncology Group performance status (ECOG-PS), Model for End Stage Liver Disease (MELD) score, αFP, MVI, satellitosis and R1 resection as independent risk factors for survival, without any impact of LI-RADS classification. Last, MELD score, log10αFP, satellitosis and R1 resection resulted as independent risk factors for cancer-specific survival, while LI-RADS class did not exert any significant impact. Conclusions: Our results suggest an association of LR-5 class with unfavorable pathological characteristics of resected HCC; tumor histology and underlying patient characteristics such as age, ECOG-PS and liver disease severity exert a significant impact on postoperative oncological outcomes.

Clinical application of advances and innovation in radiation treatment of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) management has evolved over the past two decades, with the development of newer treatment modalities. While various options are available, unmet needs are reflected through the mixed treatment outcome for intermediate-stage HCC. As HCC is radiosensitive, radiation therapies have a significant role in management. Radiation therapies offer local control for unresectable lesions and for patients who are not surgical candidates. Radiotherapy also provides palliation in metastatic disease, and acts as a bridge to resection and transplantation in selected patients. Advancements in radiotherapy modalities offer improved dose planning and targeted delivery, allowing for better tumor response and safer dose escalations while minimizing the risks of radiation-induced liver damage. Radiotherapy modalities are broadly classified into external beam radiation therapy and selective internal radiation therapy. With emerging modalities, radiotherapy plays a complementary role in the multidisciplinary care of HCC patients.

AIM

We aim to provide an overview of the role and clinical application of radiation therapies in HCC management.

RELEVANCE FOR PATIENTS

The continuous evolution of radiotherapy techniques allows for improved therapeutic outcomes while mitigating unwanted adverse effects, making it an attractive modality in HCC management. Rigorous clinical studies, quality research and comprehensive datasets will further its application in the present era of evidence-based practice in Medicine.

LR-M Observations on Contrast-Enhanced Ultrasound: Detection of Hepatocellular Carcinoma Using Additional Features in Comparison with Current LI-RADS Criteria

Background: Contrast-enhanced ultrasound (CEUS) LI-RADS assigns category LR-M for observations that are definitely or probably malignant but that are not specific on imaging for hepatocellular carcinoma (HCC). A high percentage of LR-M observations represent HCC. Objective: To retrospectively evaluate the utility of additional features, beyond conventional LI-RADS major features, for detecting HCC among LR-M observations on CEUS. Methods: This retrospective study included 174 patients (145 men, 29 women; mean age, 53 years) at high-risk for HCC who underwent CEUS from August 2014 to June 2016, demonstrating an LR-M observation using CEUS LI-RADS version 2017. Two radiologists independently assessed CEUS images for major features and four additional features (chaotic vessels, peripheral circular artery, clear boundary of the tumor enhancement, clear boundary of the intratumoral nonenhanced area). Diagnostic performance was assessed of four proposed criteria for the detection of HCC among LR-M observations. The impact on HCC detection of criteria based on the additional findings was further explored. Histology or composite imaging and clinical follow-up served as reference standard. Results: The 174 LR-M observations included 142 HCCs and 32 non-HCCs (20 intrahepatic cholangiocarcinomas, 5 combined hepatocellular-cholangiocarcinomas, 7 benign lesions). Interreader agreement of the additional features, expressed as kappa, ranged from 0.65 to 0.88. Two of the additional features exhibited PPV ≥95.0% for HCC: chaotic vessels (95.0%) and peripheral circular arteries (98.1%). The presence of either of these two additional features achieved sensitivity of 50.7%, specificity of 90.6%, PPV of 96.0%, and NPV of 29.3% for HCC. Three other explored criteria incorporating variations of major LI-RADS features, but not the additional features, had sensitivities of 55.6%-96.5%, specificities of 49.6%-68.8%, PPVs of 87.8%-90.6%, and NPVs of 25.0%-75.0%. Criteria using additional features recategorized 75 of 174 LR-M observations as LR-5, of which 72 were HCC. Conclusion: The presence of chaotic vessels and/or peripheral circular artery had high specificity and PPV for HCC among LR-M observations. Other explored criteria based on major features did not achieve higher specificity or PPV. Clinical Impact: Clinical adoption of the additional CEUS features could help establish the diagnosis of HCC noninvasively and avoid the need for biopsy of LR-M observations.

Hepatocellular Carcinoma Staging: Differences Between Radiologic and Pathologic Systems and Relevance to Patient Selection and Outcomes in Liver Transplantation

Liver transplant is indicated with curative intent for patients with early-stage hepatocellular carcinoma (HCC). The radiologic T category is used to determine candidacy and priority of patients on the waiting list. After transplant, the explant liver pathologic TNM stage is used as a predictor of postoperative outcomes and overall prognosis. Although the comparison of radiologic and pathologic T categories for concordance is often considered to be straightforward, the staging conventions significantly differ. Not accounting for these differences is in part the reason for the high rates of radiologic-pathologic discordance reported in the literature, with inconsistent terminology being an additional source of confusion when evaluating concordance. These factors may affect the understanding of important radiopathologic phenotypes of disease and the adequate investigation of their prognostic capabilities. The aims of this article are to provide an overview of the pathologic and radiologic TNM staging systems for HCC while describing staging procedures, emphasize the differences between these staging systems to highlight the limitations of radiologic-pathologic stage correlation, present a review of the literature on the prognostic value of individual features used for HCC staging; and signal significant aspects of preoperative risk stratification that could be improved to positively impact posttransplant outcomes.

Locoregional Treatments for Bridging and Downstaging HCC to Liver Transplantation

Liver transplantation (LT) is the first-line treatment for patients diagnosed with unresectable early-stage hepatocellular carcinoma (HCC) in the setting of cirrhosis. It is well known that HCC patients within the Milan criteria (solitary tumour ≤ 5 cm or ≤3 tumours, each <3 cm) could undergo LT with excellent results. However, there is a growing tendency to enlarge inclusion criteria since the Milan criteria are nowadays considered too restrictive and may exclude patients who would benefit from LT. On the other hand, there is a persistent shortage of donor organs. In this scenario, there is consensus about the role of loco-regional therapy (LRT) during the waiting list to select patients who would benefit more from LT, reducing the risk of drop off from the waiting list as well as decreasing tumour dimension to meet acceptable criteria for LT. In this review, current evidence on the safety, efficacy and utility of LRTs as neoadjuvant therapies before LT are summarized.

Downstaging Outcomes for Hepatocellular Carcinoma: Results From the Multicenter Evaluation of Reduction in Tumor Size before Liver Transplantation (MERITS-LT) Consortium

BACKGROUND & AIMS

United Network of Organ Sharing (UNOS) has adopted uniform criteria for downstaging (UNOS-DS) of hepatocellular carcinoma (HCC) before liver transplantation (LT), but the downstaging success rate and intention-to-treat outcomes across broad geographic regions are unknown.

METHODS

In this first multiregional study (7 centers, 4 UNOS regions), 209 consecutive patients with HCC undergoing downstaging based on UNOS-DS criteria were prospectively evaluated from 2016 to 2019.

RESULTS

Probability of successful downstaging to Milan criteria and dropout at 2 years from the initial downstaging procedure was 87.7% and 37.3%, respectively. Pretreatment with lectin-reactive α-fetoprotein ≥10% (hazard ratio, 3.7; P = .02) was associated with increased dropout risk. When chemoembolization (n = 132) and yttrium-90 radioembolization (n = 62) were compared as the initial downstaging treatment, there were no differences in Modified Response Evaluation Criteria In Solid Tumors response, probability of or time to successful downstaging, waiting list dropout, or LT. Probability of LT at 3 years was 46.6% after a median of 17.2 months. In the explant, 17.5% had vascular invasion, and 42.8% exceeded Milan criteria (understaging). The only factor associated with understaging was the sum of the number of lesions plus largest tumor diameter on the last pre-LT imaging, and the odds of understaging increased by 35% per 1-unit increase in this sum. Post-LT survival at 2 years was 95%, and HCC recurrence occurred in 7.9%.

CONCLUSION

In this first prospective multiregional study based on UNOS-DS criteria, we observed a successful downstaging rate of >80% and similar efficacy of chemoembolization and yttrium-90 radioembolization as the initial downstaging treatment. A high rate of tumor understaging was observed despite excellent 2-year post-LT survival of 95%. Additional LRT to reduce viable tumor burden may reduce tumor understaging.

Measuring HCC Tumor Size in MRI-The Sequence Matters!

BACKGROUND

The aim of this paper was to assess and compare the accuracy of common magnetic resonance imaging (MRI) pulse sequences in measuring the lesion sizes of hepatocellular carcinomas (HCCs) with respect to the Milan criteria and histopathology as a standard of reference.

METHODS

We included 45 patients with known HCC who underwent contrast-enhanced MRI of the liver prior to liver transplantation or tumor resection. Tumor size was assessed pathologically for all patients. The MRI protocol contained axial T2-weighted images as well as T1-weighted imaging sequences before and after application of Gd-EOB-DTPA. Tumor diameters, the sharpness of lesions, and the presence of artifacts were evaluated visually on all available MRI sequences. MRI measurements and pathologically assessed tumor dimensions were correlated using Pearson's correlation coefficient and Bland-Altman plots. The rate of misclassifications following Milan criteria was assessed.

RESULTS

The mean absolute error (in cm) of MRI size measurements in comparison to pathology was the smallest for the hepatobiliary phase T1-weighted acquisition (0.71 ± 0.70 cm, r = 0.96) and largest for the T2w turbo-spin-echo (TSE) sequence (0.85 ± 0.78 cm, r = 0.94). The misclassification rate regarding tumor size under the Milan criteria was lowest for the T2w half-Fourier acquisition single-shot turbo spin-echo sequence and the hepatobiliary phase T1w acquisition (each 8.6%). The highest rate of misclassification occurred in the portal venous phase T1w acquisition and T2w TSE sequence (each 14.3%).

CONCLUSIONS

The hepatobiliary phase T1-weighted acquisition seems to be most accurate among commonly used MRI sequences for measuring HCC tumor size, resulting in low rates of misclassification with respect to the Milan criteria.

Radiation Segmentectomy

Radiation segmentectomy is an yttrium-90 transarterial radioembolization treatment where a high radiation dose is administered to a small volume of liver to achieve a high tumoricidal dose to a target with anatomic surgical precision while sparing surrounding parenchyma. This therapeutic modality is often used to treat hepatocellular carcinoma, and recent studies have demonstrated that radiation segmentectomy is an effective treatment as a neoadjuvant to transplant, resection, or as a standalone treatment. This article provides a review of radiation segmentectomy, indications for treatment, recent outcome data, and guidelines for postprocedural management.

Effects of Combined Epidural Anesthesia and General Anesthesia on Cognitive Function and Stress Responses of Elderly Patients Undergoing Liver Cancer Surgery

This study aimed at exploring the effects of combined epidural anesthesia and general anesthesia on the cognitive function and stress responses of elderly patients undergoing liver cancer surgery. One hundred and fifteen elderly patients were enrolled as research subjects. They were admitted to our hospital and underwent liver cancer surgery from August 2017 to May 2019. Fifty five cases were treated with general anesthesia (GA) (GA group), while the other sixty cases were treated with combined epidural anesthesia and general anesthesia (joint group). Scoring standards of Mini-Mental State Examination (MMSE) were used to evaluate the patients before and after operation. Their operating time, total fluid input (TFI), spontaneous breathing recovery time (SBRT), preoperative and postoperative indices of stress responses (epinephrine (EPI), cortisol (Cor), and norepinephrine (NE)), and postoperative adverse reactions were observed. There were statistically significant differences between the two groups with respect to anesthesia time, TFI, postoperative SBRT, and postoperative directional recovery time (DRT) (cP < 0.05). There was no difference in operating time, total fluid loss (TFL), and hospitalization time (P > 0.05). After operation, patients in both groups experienced a cognitive decline of different degrees and the MMSE scores decreased. There was no significant difference in the score between the two groups before operation and 3 days and 7 days after operation (P > 0.05). The score was significantly better in the joint group than that in the GA group at 6 hours and 1 day after operation (P < 0.05). There were no significant differences in levels of EPI, Cor, and NE between the two groups before operation (P > 0.05), but there were significant differences after operation. The total incidence of postoperative adverse reactions was 11.67% in the joint group and 25.45% in the GA group. In conclusion, combined epidural anesthesia and general anesthesia can significantly reduce postoperative cognitive dysfunction and inhibit postoperative stress responses in elderly patients undergoing liver cancer surgery. It has good application value in clinical practice.

Ultrasound Liver Imaging Reporting and Data System (US LI-RADS): An Overview with Technical and Practical Applications

The Ultrasound Liver Imaging Reporting and Data System (US LI-RADS), introduced in 2017 by the American College of Radiology, standardizes the technique, interpretation, and reporting of screening and surveillance ultrasounds intended to detect hepatocellular carcinoma in high-risk patients. These include patients with cirrhosis of any cause as well as subsets of patients with chronic hepatitis B viral infection. The US LI-RADS scheme is composed of an ultrasound category and a visualization score: ultrasound categories define the exam as negative, subthreshold, or positive and direct next steps in management; visualization scores denote the expected sensitivity of the exam, based on adequacy of liver visualization with ultrasound. Since its introduction, multiple institutions across the United States have implemented US LI-RADS. This review includes a background of hepatocellular carcinoma and US LI-RADS, definition of screening/surveillance population, recommendations and tips for technique, interpretation, and reporting, and preliminary outcomes analysis.

Imaging Features at the Periphery: Hemodynamics, Pathophysiology, and Effect on LI-RADS Categorization

Liver lesions have different enhancement patterns at dynamic contrast-enhanced imaging. The Liver Imaging Reporting and Data System (LI-RADS) applies the enhancement kinetic of liver observations in its algorithms for imaging-based diagnosis of hepatocellular carcinoma (HCC) in at-risk populations. Therefore, careful analysis of the spatial and temporal features of these enhancement patterns is necessary to increase the accuracy of liver mass characterization. The authors focus on enhancement patterns that are found at or around the margins of liver observations-many of which are recognized and defined by LI-RADS, such as targetoid appearance, rim arterial phase hyperenhancement, peripheral washout, peripheral discontinuous nodular enhancement, enhancing capsule appearance, nonenhancing capsule appearance, corona enhancement, and periobservational arterioportal shunts-as well as peripheral and periobservational enhancement in the setting of posttreatment changes. Many of these are considered major or ancillary features of HCC, ancillary features of malignancy in general, features of non-HCC malignancy, features associated with benign entities, or features related to treatment response. Distinction between these different patterns of enhancement can help with achieving a more specific diagnosis of HCC and better assessment of response to local-regional therapy. ^©RSNA, 2021.

A retrospective single-centre analysis of the oncological impact of LI-RADS classification applied to Metroticket 2.0 calculator in liver transplantation: every nodule matters

Although the diagnostic value of Liver Imaging Reporting and Data System (LI-RADS) protocol is well recognized in clinical practice, its role in liver transplant (LT) setting is under-explored. We sought to evaluate the oncological impact of LI-RADS classification applied to Metroticket 2.0 calculator in a single-centre retrospective cohort of transplanted hepatocellular carcinoma (HCC) patients, exploring which LI-RADS subclasses need to be considered in order to grant the best Metroticket 2.0 performance. The most recent pre-LT imaging of 245 patients undergoing LT for HCC between 2005 and 2015 was retrospectively and blindly reviewed, classifying all nodules according to LI-RADS protocol. Metroticket 2.0 accuracy was subsequently tested incorporating all vital nodules identified during multi-disciplinary team (MDT) meetings attended before LI-RADS reclassification of the latest pre-LT imaging, LR-5 and LR-treatment-viable (LR-TR-V), LR-4/5 and LR-TR-V, and LR-3/4/5 and LR-TR-V nodules respectively. Considering their extremely low probability for harbouring HCC, LR-1 and LR-2 nodules were not considered in this analysis. Incorporation of all HCCs identified during MDT meetings attended before LI-RADS reclassification of the latest pre-LT imaging resulted in a Metroticket 2.0 c-index of 0.72, [95% confidence interval (CI) 0.64-0.80]. Metroticket 2.0 c-index dropped to 0.60 [95% CI: 0.48-0.72] when LI-RADS-5 and LI-RADS-TR-V (P = 0.0089) or LI-RADS-5, LI-RADS-4 and LI-RADS-TR-V (P = 0.0068) nodules were entered in the calculator. Conversely, addition of LI-RADS-3 HCCs raised the Metroticket 2.0 c-index to 0.65 [95% CI: 0.54-0.86], resulting in a not statistically significant diversion from the original performance (0.72 vs. 0.65; P = 0.08). Exclusion of LR-3 and LR-4 nodules from Metroticket 2.0 calculator resulted in a significant drop in its accuracy. Every nodule with an intermediate-to-high probability of harbouring HCC according to LI-RADS protocol seems to contribute to tumour burden and should be entered in the Metroticket 2.0 calculator in order to grant appropriate performance.

Facile Assembly of Thermosensitive Liposomes for Active Targeting Imaging and Synergetic Chemo-/Magnetic Hyperthermia Therapy

Cancer stem cells (CSCs) are thought to be responsible for the recurrence of liver cancer, highlighting the urgent need for the development of effective treatment regimens. In this study, 17-allylamino-17-demethoxygeldanamycin (17-AAG) and thermosensitive magnetoliposomes (TMs) conjugated to anti-CD90 (CD90@17-AAG/TMs) were developed for temperature-responsive CD90-targeted synergetic chemo-/magnetic hyperthermia therapy and simultaneous imaging in vivo. The targeting ability of CD90@DiR/TMs was studied with near-infrared (NIR) resonance imaging and magnetic resonance imaging (MRI), and the antitumor effect of CD90@17-AAG/TM-mediated magnetic thermotherapy was evaluated in vivo. After treatment, the tumors were analyzed with Western blotting, hematoxylin and eosin staining, and immunohistochemical (IHC) staining. The relative intensity of fluorescence was approximately twofold higher in the targeted group than in the non-targeted group, while the T 2 relaxation time was significantly lower in the targeted group than in the non-targeted group. The combined treatment of chemotherapy, thermotherapy, and targeting therapy exhibited the most significant antitumor effect as compared to any of the treatments alone. The anti-CD90 monoclonal antibody (mAb)-targeted delivery system, CD90@17-AAG/TMs, exhibited powerful targeting and antitumor efficacies against CD90+ liver cancer stem cells in vivo.

Hepatocarcinogenesis: Radiology-Pathology Correlation

In the background of chronic liver disease, hepatocellular carcinoma develops via a complex, multistep process called hepatocarcinogenesis. This article reviews the causes contributing to the process. Emphasis is made on the imaging manifestations of the pathologic changes seen at many stages of hepatocarcinogenesis, from regenerative nodules to dysplastic nodules and then to hepatocellular carcinoma.

Magnetic Resonance Imaging of Nonhepatocellular Malignancies in Chronic Liver Disease

Hepatocellular carcinoma (HCC) is the most common liver malignancy associated with chronic liver disease. Nonhepatocellular malignancies may also arise in the setting of chronic liver disease. The imaging diagnosis of non-HCC malignancies may be challenging. Non-HCC malignancies in patients with chronic liver disease most commonly include intrahepatic cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma, and less commonly hepatic lymphomas and metastases. On MR imaging, non-HCC malignancies often demonstrate a targetoid appearance, manifesting as rim arterial phase hyperenhancement, peripheral washout, central delayed enhancement, and peripheral restricted diffusion. When applying the Liver Imaging Reporting and Data System algorithm, observations with targetoid appearance are categorized as LR-M.

Chronic Liver Disease and Liver Cancer: What the Hepatologists, Oncologists, and Surgeons Want to Know from Radiologists

Effective communication between radiologists and physicians involved in the management of patients with chronic liver disease is paramount to ensuring appropriate and advantageous incorporation of liver imaging findings into patient care. This review discusses the clinical benefits of innovations in radiology reporting, what information the various stakeholders wish to know from the radiologist, and how radiology can help to ensure the effective communication of findings.

How to Use LI-RADS to Report Liver CT and MRI Observations

Primary liver cancer is the fourth leading cause of cancer-related deaths worldwide, with hepatocellular carcinoma (HCC) comprising the vast majority of primary liver malignancies. Imaging plays a central role in HCC diagnosis and management. As a result, the content and structure of radiology reports are of utmost importance in guiding clinical management. The Liver Imaging Reporting and Data System (LI-RADS) provides guidance for standardized reporting of liver observations in patients who are at risk for HCC. LI-RADS standardized reporting intends to inform patient treatment and facilitate multidisciplinary communication and decisions, taking into consideration individual clinical factors. Depending on the context, observations may be reported individually, in aggregate, or as a combination of both. LI-RADS provides two templates for reporting liver observations: in a single continuous paragraph or in a structured format with keywords and imaging findings. The authors clarify terminology that is pertinent to reporting, highlight the benefits of structured reports, discuss the applicability of LI-RADS for liver CT and MRI, review the elements of a standardized LI-RADS report, provide guidance on the description of LI-RADS observations exemplified with two case-based reporting templates, illustrate relevant imaging findings and components to be included when reporting specific clinical scenarios, and discuss future directions. An invited commentary by Yano is available online. Online supplemental material is available for this article. Work of the U.S. Government published under an exclusive license with the RSNA.

Deep learning-assisted differentiation of pathologically proven atypical and typical hepatocellular carcinoma (HCC) versus non-HCC on contrast-enhanced MRI of the liver

OBJECTIVES

To train a deep learning model to differentiate between pathologically proven hepatocellular carcinoma (HCC) and non-HCC lesions including lesions with atypical imaging features on MRI.

METHODS

This IRB-approved retrospective study included 118 patients with 150 lesions (93 (62%) HCC and 57 (38%) non-HCC) pathologically confirmed through biopsies (n = 72), resections (n = 29), liver transplants (n = 46), and autopsies (n = 3). Forty-seven percent of HCC lesions showed atypical imaging features (not meeting Liver Imaging Reporting and Data System [LI-RADS] criteria for definitive HCC/LR5). A 3D convolutional neural network (CNN) was trained on 140 lesions and tested for its ability to classify the 10 remaining lesions (5 HCC/5 non-HCC). Performance of the model was averaged over 150 runs with random sub-sampling to provide class-balanced test sets. A lesion grading system was developed to demonstrate the similarity between atypical HCC and non-HCC lesions prone to misclassification by the CNN.

RESULTS

The CNN demonstrated an overall accuracy of 87.3%. Sensitivities/specificities for HCC and non-HCC lesions were 92.7%/82.0% and 82.0%/92.7%, respectively. The area under the receiver operating curve was 0.912. CNN's performance was correlated with the lesion grading system, becoming less accurate the more atypical imaging features the lesions showed.

CONCLUSION

This study provides proof-of-concept for CNN-based classification of both typical- and atypical-appearing HCC lesions on multi-phasic MRI, utilizing pathologically confirmed lesions as "ground truth."

KEY POINTS

• A CNN trained on atypical appearing pathologically proven HCC lesions not meeting LI-RADS criteria for definitive HCC (LR5) can correctly differentiate HCC lesions from other liver malignancies, potentially expanding the role of image-based diagnosis in primary liver cancer with atypical features. • The trained CNN demonstrated an overall accuracy of 87.3% and a computational time of < 3 ms which paves the way for clinical application as a decision support instrument.