Preoperative assessment of microvascular invasion risk using gadoxetate-enhanced MRI for predicting outcomes after liver transplantation for single hepatocellular carcinoma within the Milan criteria.

OBJECTIVE: To compare therapeutic outcomes after liver transplantation (LT) between hepatocellular carcinomas (HCC) with low and high risk for microvascular invasion (MVI) within the Milan criteria evaluated preoperatively. METHODS: Eighty patients with a single HCC who underwent LT as the initial therapy between 2008 and 2017 were included from two tertiary referral medical centers in a HBV-predominant population. A preoperative MVI-risk model was used to identify low- and high-risk patients. Recurrence-free survival (RFS) after LT between the two risk groups was compared using Kaplan-Meier curves with the log-rank test. Prognostic factors for RFS were identified using a multivariable Cox hazard regression analysis. RESULTS: Eighty patients were included (mean age, 51.8 years +/- 7.5 [standard deviation], 65 men). Patients were divided into low-risk (n = 64) and high-risk (n = 16) groups for MVI. The RFS rates after LT were significantly lower in the MVI high-risk group compared to the low-risk group at 1 year (75.0% [95% CI: 56.5-99.5%] vs. 96.9% [92.7-100%], p = 0.048), 3 years (62.5% [42.8-91.4%] vs. 95.3% [90.3-100%], p = 0.008), and 5 years (62.5% [42.8-91.4%] vs. and 95.3% [90.3-100%], p = 0.008). In addition, multivariable analysis showed that MVI high risk was the only significant factor for poor RFS (p = 0.016). CONCLUSION: HCC patients with a high risk of MVI showed significantly lower RFS after LT than those without. This model could aid in selecting optimal candidates in addition to the Milan criteria when considering upfront LT for patients with HCC if alternative treatment options are available. CLINICAL RELEVANCE STATEMENT: High risk for microvascular invasion (MVI) in hepatocellular carcinoma patients lowered recurrence-free survival after liver transplantation, despite meeting the Milan criteria. Identifying MVI risk could aid candidate selection for upfront liver transplantation, particularly if alternative treatments are available. KEY POINTS: • A predictive model-derived microvascular invasion (MVI) high- and low-risk groups had a significant difference in the incidence of MVI on pathology. • Recurrence-free survival after liver transplantation (LT) for single hepatocellular carcinoma (HCC) within the Milan criteria was significantly different between the MVI high- and low-risk groups. • The peak incidence of tumor recurrence was 20 months after liver transplantation, probably indicating that HCC with high risk for MVI had a high risk of early (≤ 2 years) tumor recurrence.

Bile duct diffusion-weighted image hyperintensity predicts intrahepatic biliary complications after ABO-incompatible liver transplantation.

OBJECTIVES: We assessed the value of the diffusion-weighted image (DWI) for predicting intrahepatic biliary complications (IHBC) after ABO-incompatible liver transplantation (ABOi-LT), potentially leading to refractory cholangitis. MATERIALS AND METHODS: In this retrospective study at a single center, 56 patients who underwent ABOi-LT from March 2021 to January 2023 were analyzed. All received magnetic resonance cholangiopancreatography (MRCP) and DWI during the postoperative hospitalization. MRCP findings, including bile duct DWI hyperintensity, were assessed. Participants suspected of having a biliary infection or obstructive jaundice underwent endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic biliary drainage (PTBD) during the follow-up. Non-anastomotic biliary strictures on cholangiography were classified as IHBC, as either perihilar or diffuse form. DWI hyperintensity was compared between groups with and without IHBC. Logistic regression analysis was performed to identify independent risk factors for IHBC. RESULTS: Of the 55 participants (median age 55 years, 39 males), IHBC was diagnosed in eight patients over a median follow-up of 15.9 months (range 5.6-31.1). Bile duct DWI hyperintensity was observed in 18 patients. Those with DWI hyperintensity exhibited a higher IHBC incidence (6/18, 33.3% vs. 2/36, 5.6%; p = 0.01), and more frequently developed the diffuse type IHBC (4/18, 22.2% vs. 1/36, 2.8%; p = 0.04). Regression analysis indicated that bile duct DWI hyperintensity is an independent risk factor for IHBC (odds ratio (OR) 10.1; 95% confidence interval (CI) 1.4, 71.2; p = 0.02) and its diffuse form (OR 15.3; 95% CI 1.2, 187.8; p = 0.03). CONCLUSION: Postoperative DWI hyperintensity of bile ducts can serve as a biomarker predicting IHBC after ABOi-LT. CLINICAL RELEVANCE STATEMENT: Postoperative diffusion-weighted image hyperintensity of the bile duct can be used as a biomarker to predict intrahepatic biliary complications and aid in identifying candidates who may benefit from additional management for antibody-mediated rejection. KEY POINTS: Intrahepatic biliary complications following ABO-incompatible liver transplantation can cause biliary stricture and biloma formation. Bile duct hyperintensity on early postoperative diffusion-weighted imaging was associated with increased intrahepatic biliary complication risk. This marker is an additional method for identifying individuals who require intensive management to prevent complications.

LI-RADS category is associated with treatment outcomes of small single HCC: surgical resection vs. radiofrequency ablation.

OBJECTIVES: To assess whether the Liver Imaging Reporting and Data System (LI-RADS) category is associated with the treatment outcomes of small single hepatocellular carcinoma (HCC) after surgical resection (SR) and radiofrequency ablation (RFA). METHODS: This retrospective study included 357 patients who underwent SR (n = 209) or RFA (n = 148) for a single HCC of ≤ 3 cm between 2014 and 2016. LI-RADS categories were assigned. Overall survival (OS), recurrence-free survival (RFS), and local tumor progression (LTP) rates after treatment were compared according to the LI-RADS category (LR-4/5 vs. LR-M) before and after propensity score matching (PSM). Prognostic factors for treatment outcomes were assessed. RESULTS: In total, 357 patients (mean age, 59 years; men, 272) with 357 HCCs (294 LR-4/5 and 63 LR-M) were included. After PSM (n = 78 in each treatment group), there were 10 and 11 LR-M HCCs in the SR and RFA group, respectively. There were no significant differences in OS or RFS. However, SR provided a lower 5-year LTP rate than RFA (1.4% vs. 14.9%, p = 0.001). SR provided a lower 5-year LTP rate than RFA for LR-M HCCs (0% vs. 34.4%, p = 0.062) and LR-4/5 HCCs (1.5% vs. 12.0%, p = 0.008). The LI-RADS category was the sole risk factor associated with poor OS (hazard ratio [HR] 3.79, p = 0.004), RFS (HR 2.12; p = 0.001), and LTP (HR 2.89; p = 0.032). CONCLUSION: LI-RADS classification is associated with the treatment outcome of HCC, supporting favorable outcomes of SR over RFA for LTP, especially for HCCs categorized as LR-M. CLINICAL RELEVANCE STATEMENT: Liver Imaging Reporting and Data System category has a potential prognostic role, supporting favorable outcomes of surgical resection over radiofrequency ablation for local tumor progression, especially for hepatocellular carcinoma categorized as LR-M. KEY POINTS: • SR provided a lower 5-year LTP rate than RFA for HCCs categorized as LR-M (0% vs. 34.4%, p = 0.062) and HCCs categorized as LR-4/5 (1.5% vs. 12.0%, p = 0.008). • There is a steeply increased risk of LTP within 1 year after RFA for LR-M HCCs, compared to SR. • The LI-RADS category was the sole risk factor associated with poor OS (HR 3.79, p = 0.004), RFS (HR 2.12; p = 0.001), and LTP (HR 2.89; p = 0.032) in patients with HCC of ≤ 3 cm treated with SR or RFA.

Prediction of epithelial-to-mesenchymal transition molecular subtype using CT in gastric cancer.

OBJECTIVES: To develop a prediction model with computed tomography (CT) images and to build a nomogram incorporating known clinicopathologic variables for individualized estimation of epithelial-to-mesenchymal transition (EMT) subtype gastric cancer. METHODS: Patients who underwent primary resection of gastric cancer (GC) and molecular subgroup analysis (n = 451) were reviewed. Multivariable analysis using a stepwise variable selection method was performed to build a predictive model for EMT subtype GC. A nomogram using the results of the multivariable analysis was constructed. An optimal cutoff value of total prognostic points of the nomogram for the prediction of EMT subtype was determined. The predictive model for the EMT subtype was internally validated by bootstrap resampling method. RESULTS: There were 88 patients with EMT subtype and 363 patients with non-EMT subtype based on transcriptome analysis. The patient's age, Lauren classification, and mural stratification on CT were variables selected for the predictive model. The area under the curve (AUC) of the model was 0.865, and the validated AUC of the bootstrap sample was 0.860. The optimal cutoff value of total prognostic points for the prediction of EMT subtype was 94.622, with 90.9% sensitivity, 67.2% specificity, and 71.8% accuracy. CONCLUSION: A predictive model using patient's age, Lauren classification, and mural stratification on CT for EMT molecular subtype GC was made. A nomogram was built which would serve as a useful screening tool for an individualized estimate of EMT subtype. KEY POINTS: • A predictive model for epithelial-to-mesenchymal transition (EMT) subtype incorporating patient's age, Lauren classification, and mural stratification on CT was built. • The predictive model had high diagnostic accuracy (area under the curve (AUC) = 0.865) and was validated (bootstrap AUC = 0.860). • Adding CT findings to clinicopathologic variables increases the accuracy of the predictive model than using only.

LI-RADS Version 2018 Targetoid Appearances on Gadoxetic Acid-Enhanced MRI: Interobserver Agreement and Diagnostic Performance for the Differentiation of HCC and Non-HCC Malignancy.

BACKGROUND. In LI-RADS version 2018, observations showing at least one of five targetoid appearances in different sequences or postcontrast phases are categorized LR-M, indicating likely non-hepatocellular carcinoma (HCC) malignancy. OBJECTIVE. The purpose of this study was to evaluate interobserver agreement for LI-RADS targetoid appearances among a large number of radiologists of varying experience and the diagnostic performance of targetoid appearances for differentiating HCC from non-HCC malignancy. METHODS. This retrospective study included 100 patients (76 men, 24 women; mean age, 58 ± 9 [SD] years) at high risk of HCC who underwent gadoxetic acid-enhanced MRI within 30 days before hepatic tumor resection (25 randomly included patients with non-HCC malignancy [13, intrahepatic cholangiocarcinoma; 12, combined HCC-cholangiocarcinoma]; 75 matched patients with HCC). Eight radiologists (four more experienced [8-15 years]; four less experienced [1-5 years]) from seven institutions independently assessed observations for the five targetoid appearances and LI-RADS categorization. Interobserver agreement and diagnostic performance for non-HCC malignancy were evaluated. RESULTS. Interobserver agreement was poor for peripheral washout (κ = 0.20); moderate for targetoid transitional phase or hepatobiliary phase appearance (κ = 0.33), delayed central enhancement (κ = 0.37), and targetoid restriction (κ = 0.43); and substantial for rim arterial phase hyperenhancement (κ = 0.61). Agreement was fair for at least one targetoid appearance (κ = 0.36) and moderate for at least two, three, or four targetoid appearances (κ = 0.43-0.51). Agreement for individual targetoid appearances was not significantly different between more experienced and less experienced readers other than for targetoid restriction (κ = 0.63 vs 0.43; p = .001). Agreement for at least one targetoid appearance was fair among more experienced (κ = 0.29) and less experienced (κ = 0.37) reviewers. Agreement for at least two, three, or four targetoid appearances was moderate to substantial among more experienced reviewers (κ = 0.45-0.63) and moderate among less experienced reviewers (κ = 0.42-0.56). Existing LR-M criteria of at least one targetoid appearance had median accuracy for non-HCC malignancy of 62%, sensitivity of 84%, and specificity of 54%. For all reviewers, accuracy was highest when at least three (median accuracy, 79%; sensitivity, 68%; specificity, 82%) or four (median accuracy, 80%; sensitivity, 54%; specificity, 88%) targetoid appearances were required. CONCLUSION. Targetoid appearances and LR-M categorization exhibited considerable interobserver variation among both more and less experienced reviewers. CLINICAL IMPACT. Requiring multiple targetoid appearances for LR-M categorization improved interobserver agreement and diagnostic accuracy for non-HCC malignancy.

Laparoscopic radiofrequency ablation of subcapsular hepatocellular carcinomas: risk factors related to a technical failure.

BACKGROUND: This study aimed to evaluate the risk factors related to a technical failure after laparoscopic radiofrequency ablation (RFA) for subcapsular hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: A total of 110 patients with 114 HCCs who underwent laparoscopic RFA for HCCs (new HCC [n = 85] and local tumor progression [LTP] [n = 29]) between January 2013 and December 2018 were included. We evaluated the incidence of technical failure on immediate post-RFA CT images. Risk factors for a technical failure after laparoscopic RFA were assessed using univariable logistic regression analyses. The cumulative LTP rate was estimated using the Kaplan-Meier method. RESULTS: Technical failure was noted in 3.5% (4/114) of the tumors. All four tumors that showed a technical failure were cases of LTP from previous treatment and were invisible on laparoscopy. On univariate analysis, LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as risk factors for a technical failure. The cumulative LTP rates at 1, 3, and 5 years were estimated to be 2.8%, 4.8%, and 4.8%, respectively. CONCLUSIONS: LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as the risk factors for a technical failure after laparoscopic RFA.

EASL versus LI-RADS: Intra-individual comparison of MRI with extracellular contrast and gadoxetic acid for diagnosis of small HCC.

BACKGROUND & AIMS: Liver Imaging Reporting and Data System (LI-RADS) and European Association for the Study (EASL) criteria for hepatocellular carcinoma (HCC) diagnosis have been updated in 2018. We aimed to compare the HCC diagnostic performance of LI-RADS and EASL criteria with extracellular contrast agents-MRI (ECA-MRI) and hepatobiliary agents-MRI (HBA-MRI). METHODS: We prospectively evaluated 179 participants with cirrhosis (n = 105) or non-cirrhotic chronic hepatitis B (CHB) (n = 74) who underwent both ECA-MRI and HBA-MRI before surgery for de novo nodule(s) measuring 10-30 mm. We compared the HCC diagnostic performance of EASL and LR-5 in both MRIs. RESULTS: In an analysis of 215 observations (175 HCCs, 17 non-HCC malignancies and 23 benign lesions) identified from cirrhotic or non-cirrhotic CHB participants, LR-5 with ECA-MRI provided the highest sensitivity (80.7%), followed by EASL with ECA-MRI (76.2%), LR-5 with HBA-MRI (67.3%) and EASL with HBA-MRI (63.0%, all P < .05). The specificities were comparable (89.4%-91.5%). When the analysis is limited to participants with pathological cirrhosis (123 observations), the sensitivity of LR-5 with ECA-MRI was similar to that of EASL with ECA-MRI (82.7% vs 80.2%, P = .156), but higher than LR-5 with HBA-MRI (65.1%) or EASL with HBA-MRI (62.8%, both P < .001), with comparable specificities (87.5%-91.7%). CONCLUSIONS: The LR-5 with ECA-MRI yielded the highest sensitivity with a similar specificity for HCC diagnosis in cirrhosis and non-cirrhotic CHB participants, while the sensitivities of LR-5 and EASL with ECA-MRI are similar for cirrhosis participants. This indicates non-invasive diagnosis criteria can differ by contrast agents and presence of cirrhosis.

Vanishing washout of hepatocellular carcinoma according to the presence of hepatic steatosis: diagnostic performance of CT and MRI.

OBJECTIVES: To compare the presence of washout and the diagnostic performance of computed tomography (CT) and magnetic resonance imaging (MRI) for hepatocellular carcinoma (HCC) according to the presence of hepatic steatosis. METHODS: This retrospective study included 566 patients with chronic liver disease who had undergone hepatic resection for hepatic tumors (482 HCCs and 84 non-HCCs) between January 2016 and June 2018 and had available multiphasic CT and MR images. Patients were allocated in the fatty liver (n = 141) or non-fatty liver (n = 425) group according to the presence of hepatic steatosis, defined as lipid droplets in at least 5% of hepatocytes on pathological examination. The presence of HCC washout and the diagnostic performance of CT and MRI for HCC were compared between the groups. RESULTS: HCC washout was less frequently seen in the fatty liver group than in the non-fatty liver group on CT (61.5% vs. 88.9%, p < 0.001), whereas it was similarly present on MRI in both groups (77.0% vs. 74.4%, p = 0.565). For diagnosis of HCC, the sensitivity (53.3% vs. 80.0%, p < 0.001) and accuracy (53.9% vs. 80.9%, p < 0.001) of CT were lower in the fatty liver group than in the non-fatty liver group. However, for MRI, these values were not significantly different between the groups (p > 0.05). CONCLUSIONS: Hepatic steatosis significantly decreased the performance of CT for the diagnosis of HCC, whereas it did not significantly alter the performance of MRI. KEY POINTS: • Unlike MRI, there is vanishing HCC washout on CT caused by the background hepatic steatosis. • The diagnostic performance of CT for the diagnosis of HCC was significantly altered by hepatic steatosis. • The optimal cutoff HU value of the liver parenchyma for the vanishing washout of HCC was < 50 HU on unenhanced CT images.

Rim-arterial enhancing primary hepatic tumors with other targetoid appearance show early recurrence after radiofrequency ablation.

OBJECTIVES: To evaluate early (≤ 2 years) local tumor progression (LTP), intrahepatic distant metastasis (IDR), and extrahepatic metastasis (EM) of primary hepatic malignant tumors with arterial rim enhancement (RE) after RFA in comparison with non-RE tumors. METHODS: Three hundred forty-nine patients who underwent RFA for primary hepatic malignant tumors between January 2009 and December 2016 were included. The patients' tumors were classified into non-RE, RE only (RO), and RE plus other targetoid appearances (REoT). Cumulative LTP, IDR, and EM rates at 1 and 2 years after RFA were calculated using the Kaplan-Meier method and compared using the log-rank test. Prognostic factors for the outcomes were assessed using a Cox proportional hazards model. RESULTS: There were 303 non-RE, 19 RO, and 27 REoT tumors. The REoT tumors had a significantly higher rate of IDR and EM than non-RE (p = 0.04 for IDR; and p < 0.01 for EM, respectively) at 1 year after RFA. At 2 years, LTP and EM rates were significantly higher for REoT than for non-RE (p = 0.001 for LTP; and p = 0.444 for EM, respectively). The RO tumors did not have different outcomes than non-RE at 1 and 2 years after RFA. Multivariable analysis verified that REoT was a significant factor for IDR (p = 0.04) and EM (p = 0.01) at 1 year and LTP (p = 0.02) at 2 years. CONCLUSIONS: Tumors with REoT had poor LTP, IDR, and EM within 2 years after RFA than non-RE tumors. However, tumors with RO showed similar results as non-RE tumors. KEY POINTS: • Tumors with Rim enhancement plus other targetoid appearances (REoT) had a significantly higher rate of recurrence than non-rim enhancing (RE) tumors at 1 and 2 years after RFA. • Tumors with rim enhancement only did not have different outcomes than non-RE at 1 and 2 years after RFA.

Comparison of ablation performance between dual internally cooled wet tip and conventional dual internally cooled tip radiofrequency electrodes: an experimental study in ex vivo bovine liver.

OBJECTIVE: To evaluate the performance of dual internally cooled wet tip (ICWT) radiofrequency electrodes in comparison to dual internally cooled tip (ICT) electrodes. METHODS: Twenty ablation zones were created for each type of electrodes. Planned procedure time was 6 min. Diameters of the ablation zone along the x-, y-, and z-axes (Dx, Dy, and Dz), ablation zone sphericity, quantitative sphericity measurement, and ablation volume were measured and compared between the two electrode types. Circularity of the ablation zone on the surface with x- and z- axes (zx plane) and amount of energy applied were also compared. RESULTS: Dx and Dz were significantly longer with ICWT than those with ICT (Dx: 3.0 vs. 2.8 cm, p = .018; and Dz: 2.7 vs. 2.3 cm, p < .001, respectively). Dy was not significantly different (3.0 vs. 2.9 cm, p = .220). Moreover, 85% (17/20) and 30% (6/20) of ablation zones from ICWT and ICT were spherical (p = .001), respectively. Quantitative measurement showed that ICWT was more spherical compared to ICT (0.962 vs. 0.881, p = .001). The ablation volume was also significantly higher with ICWT (11.55 vs. 9.45 cm3, p = .003). The ablation zone on the zx plane was more circular with ICWT (0.907 vs. 0.883, p = .028). The amount of energy applied was significantly bigger with ICWT (18508 vs. 16998 WS, p = .003). CONCLUSION: Dual ICWT electrodes were better able to create more spherical and larger ablation zones than dual ICT electrodes.

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.

Interobserver Variability and Diagnostic Performance of Gadoxetic Acid-enhanced MRI for Predicting Microvascular Invasion in Hepatocellular Carcinoma.

Background Accurate identification of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) before treatment is critical for selecting a proper treatment strategy. Purpose To evaluate the interobserver agreement and the diagnostic performance of the MRI assessment of MVI in HCC according to the level of radiologist experience. Materials and Methods This retrospective study included 100 patients with surgically confirmed HCCs smaller than 5 cm who underwent gadoxetic acid-enhanced MRI between 2013 and 2016. Eight postfellowship radiologists (four with 7-13 years of experience [more experienced] and four with 3-6 years of experience [less experienced]) evaluated four imaging features (nonsmooth tumor margin, irregular rim-like enhancement in the arterial phase, peritumoral arterial phase hyperenhancement, peritumoral hepatobiliary phase hypointensity) and assigned the possibility of MVI. Interobserver agreement was determined by using Fleiss κ statistics according to reviewer experience and tumor size (≤3 cm vs >3 cm). With reference standards of histopathologic specimens, the diagnostic performance in the identification of MVI was assessed by using receiver operating characteristic curve analysis. Results In 100 patients (mean age, 58 years ± 10 [standard deviation]; 70 men) with 100 HCCs (mean size, 2.8 cm ± 0.9), 39 (39%) HCCs had MVI. The overall interobserver agreement was fair to moderate for the imaging features and their combinations (κ = 0.38-0.47) and MVI probability (κ = 0.41; 95% confidence interval: 0.33, 0.45). More experienced reviewers demonstrated higher agreement in MVI probability than less experienced reviewers (κ = 0.55 vs 0.36, respectively; P = .002). Diagnostic performance of each reviewer was modest for MVI prediction (area under the receiver operating characteristic curve [AUC] range, 0.60-0.74). The AUCs for the diagnosis of MVI were lower for HCCs larger than 3 cm (range, 0.55-0.69) than for those less than or equal to 3 cm (range, 0.59-0.75). Conclusion Considerable interobserver variability exists in the assessment of microvascular invasion in hepatocellular carcinoma using MRI, even for more experienced radiologists. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Tang in this issue.

Extracellular contrast-enhanced MRI with diffusion-weighted imaging for HCC diagnosis: prospective comparison with gadoxetic acid using LI-RADS.

OBJECTIVES: The aim of this study was to evaluate the diagnostic performance of introducing diffusion-weighted imaging (DWI) as a major feature to extracellular agent (ECA)-MRI for diagnosing HCC in comparison with gadoxetic acid (hepatobiliary agent, HBA)-MRI using Liver Imaging Reporting and Data System (LI-RADS) v2018. METHODS: This was a prospective intra-individual comparison study using two different types of contrast agents for liver MRI conducted at a tertiary referral academic center. One hundred forty-seven observations in 122 patients at high risk for HCC scheduled for liver surgery were included. The sensitivity, specificity, and accuracy of LI-RADS category 5 (LR-5) for HCC diagnosis according to conventional and modified LI-RADS on ECA- and HBA-MRI were measured and compared. Modified LI-RADS incorporated hyperintensity on DWI as a major feature with ECA-MRI, and hypointensity on transitional phase (TP) and/or hepatobiliary phase (HBP) as washout appearance on HBA-MRI, respectively. RESULTS: Modified LI-RADS on ECA-MRI had higher sensitivity and accuracy than modified LI-RADS on HBA-MRI (90.3% vs. 74.9%, p < 0.001; and 91.9% vs. 76.9%, p < 0.001, respectively), as well as higher specificity, although the difference did not reach statistical significance (96.0% vs. 88.0%, p = 0.157). The specificity of modified LI-RADS ECA-MRI was slightly lower than both conventional criteria but without a significant difference (96.0% vs. 100%, p = 0.317). CONCLUSIONS: Using DWI findings as a major feature for modified LR-5 on ECA-MRI showed better sensitivity and accuracy than modified LR-5 on HBA-MRI, without significantly compromising specificity compared with conventional LR-5 on ECA- or HBA-MRI. KEY POINTS: • Prospective intra-individual comparison study using two different types of contrast agents, extracellular agent (ECA) and gadoxetic acid (hepatobiliary agent, HBA), for liver MRI was conducted. • Applying diffusion restriction of a hepatic observation on ECA-MRI as a major feature of LI-RADS v2018 resulted in higher sensitivity and accuracy of LR-5 observations for HCC diagnosis than conventional LI-RADS v2018, and even compared to modified LI-RADS using modified washout on HBA-MRI. • Despite increase in sensitivity and accuracy of LR-5 observations on modified LI-RADS on ECA-MRI, the specificity was not significantly different compared with conventional LI-RADS.

Updated 10-year outcomes of percutaneous radiofrequency ablation as first-line therapy for single hepatocellular carcinoma < 3 cm: emphasis on association of local tumor progression and overall survival.

OBJECTIVES: The purpose of this study was to evaluate the 10-year overall survival and local tumor progression (LTP) of percutaneous radiofrequency ablation (RFA) for single nodular hepatocellular carcinoma (HCC) < 3 cm using a large longitudinal hospital registry and clinical factors associated with overall survival and LTP. METHODS: A total of 467 newly diagnosed patients with single nodular HCC < 3 cm who underwent RFA as first-line therapy between January 2008 to December 2016 were analyzed. Overall survival and LTP were estimated using the Kaplan-Meier method. Cox regression and competing risks Cox regression analysis were performed to identify prognostic factors for overall survival and LTP, respectively. RESULTS: The 5- and 10-year overall survival rates after RFA were 83.7% and 74.2%, respectively. LTP (hazard ratio (HR), 2.03; 95% confidence interval (CI), 1.19-3.47) was one of the important factors for overall survival after RFA. The 5- and 10-year LTP rates after RFA were 20.4% and 25.1%, respectively. Periportal location (subdistribution HR, 2.29; 95% CI, 1.25-4.21), subphrenic location (2.25, 1.34-3.86), size ≥ 1.5-< 2.0 cm (1.88, 1.05-3.39), and size ≥ 2.0 cm (2.10, 1.14-3.86) were independent factors for LTP. CONCLUSION: Ten-year therapeutic outcomes of percutaneous RFA as first-line therapy were excellent for single HCC < 3 cm. LTP was an important prognostic factor for overall survival after RFA. Periportal and subphrenic location of HCCs and tumor size were predictors for the development of LTP after RFA. KEY POINTS: • Updated 10-year survival outcome of percutaneous radiofrequency ablation as first-line therapy for single hepatocellular carcinoma < 3 cm was higher than previously reported. • Local tumor progression was an important prognostic factor for overall survival after percutaneous radiofrequency ablation. • Periportal and subphrenic location of hepatocellular carcinomas and tumor size were predictors for the development of local tumor progression after percutaneous radiofrequency ablation.

Comparison of procedure-related complications between percutaneous cryoablation and radiofrequency ablation for treating periductal hepatocellular carcinoma.

PURPOSE: This study aimed to evaluate the incidence and severity of biliary complications after treating periductal hepatocellular carcinomas (HCCs) using either cryoablation (CA) or radiofrequency ablation (RFA) and assess independent risk factors for biliary complications after treatment. MATERIALS AND METHODS: Between July 2008 and August 2018, 949 patients with treatment-naïve HCCs underwent either RFA or CA in our institution. Of these, patients with multiple HCCs, tumors equal to or larger than 3 cm or smaller than 1 cm, and tumors with non-periductal locations were excluded. Finally, 31 patients and 25 patients were included in the RFA group and the CA group, respectively. The incidence and severity of biliary complications were compared between the RFA and CA groups. The risk factors for biliary complications were assessed using univariable and multivariable logistic regression analyses using the following variables: age, sex, tumor size, Child-Pugh score, tumor location (peripheral duct versus central duct), ablation method (RFA versus CA), the number of applicators, ablation time, and ablation volume. RESULTS: The incidence and severity of biliary complications were significantly higher in the RFA group than in the CA group (p = 0.007 and p = 0.002, respectively). In univariable and multivariable analyses, the ablation method was an independent risk factor for biliary complications (p = 0.004 and 0.013, respectively). CONCLUSIONS: The incidence and severity of biliary complications after treating HCCs abutting the bile duct are lower in CA than RFA, demonstrating that CA is safer than RFA for ablating small periductal HCCs.

Apparent diffusion coefficient as a potential marker for tumour differentiation, staging and long-term clinical outcomes in gallbladder cancer.

OBJECTIVES: To evaluate the correlation between tumour differentiation or stage of gallbladder cancer (GBC) and the apparent diffusion coefficient (ADC), as well as to assess whether ADC value can predict long-term disease-free survival (DFS) after surgery. METHODS: This retrospective study was approved by the institutional review board and the requirement for informed consent was waived. Between March 2008 and June 2016, 79 patients who underwent magnetic resonance (MR) imaging with diffusion-weighted image and subsequent surgery for GBC were included in this study. Correlations between quantitative ADC values and tumour differentiation or stage based on the American Joint Committee on Cancer (AJCC) were assessed using Spearman's correlation analysis. Prognostic factors for DFS were identified with multivariate Cox regression analysis using imaging and clinical characteristics. RESULTS: All patients were classified as having well- (n = 18), moderately (n = 35) or poorly differentiated GBCs (n = 26). The ADC value of GBCs was significantly correlated with tumour differentiation and AJCC stage (p < 0.001 and p < 0.001, respectively). Sixty-nine patients were followed up for 2.0-92.4 months (median, 23.5 months). On multivariate analysis, the significant prognostic factor for DFS was not tumour differentiation or AJCC stage but a binary tumour ADC value (hazard ratio, 4.29; p = 0.009). DFS rates were significantly different according to the classification of tumour ADC value (cut-off value = 1.04 × 10-3 mm2/s; p = 0.004). CONCLUSION: The ADC value of GBCs was significantly correlated with tumour differentiation as well as AJCC stage. In addition, it predicted long-term outcomes after surgery in patients with GBC. KEY POINTS: • ADC values of GBC and tumour differentiation were negatively correlated. • Lower ADC values of GBC were significantly correlated with higher tumour stage. • Tumour ADC value could be useful for risk stratification of GBC patients.

Percutaneous cryoablation for perivascular hepatocellular carcinoma: Therapeutic efficacy and vascular complications.

OBJECTIVES: To evaluate the therapeutic efficacy of and vascular complications associated with percutaneous cryoablation for the treatment of perivascular HCC. METHODS: Between August 2015 and September 2017, 58 consecutive patients (48 men, 10 women; mean age, 61.1 years; age range, 44-84 years) who underwent percutaneous cryoablation were included. All patients had a single perivascular HCC (mean size, 1.3 cm; Barcelona clinic liver cancer-stage 0 or A) that was in contact with hepatic vessels, ≥ 3 mm or larger in axial diameter. Local tumour progression (LTP) was estimated by the Kaplan-Meier method. In addition, several procedure-related vascular complications were evaluated immediately after treatment and during follow-up CT: peritumoral vessel thrombosis; infarction; aggressive intrasegmental recurrence (AIR) (the simultaneous development of ≥ 3 nodular or infiltrative tumours). The follow-up CT was performed in all patients 1 month after the procedure, and every 3 months thereafter. RESULTS: The median follow-up period was 22 months (range, 3-29 months). The technical success rate of cryoablation was 96.6% (56/58). The 1- and 2-year cumulative LTP rates were 3.6% and 14.6%, respectively. Although peritumoral vessel thrombosis occurred in 6.9% of cases (4/58), no cases of hepatic infarction were observed and AIR did not develop during follow-up. Half of the thombi in the peritumoral vessels immediately after cryoablation disappeared on follow-up CT images. CONCLUSION: Cryoablation could be an effective tool for the treatment of perivascular HCC with a very low risk of vascular complications. KEY POINTS: • Cryoablation allowed a high technical success rate for perivascular HCC. • Only 6.9% developed peritumoral vessel thrombosis without major vascular complications like infarction. • Two-year cumulative LTP rate was 14.6%, without aggressive tumour recurrence on follow-up.

Radiofrequency ablation for subcardiac hepatocellular carcinoma: therapeutic outcomes and risk factors for technical failure.

OBJECTIVES: To compare the therapeutic outcomes and safety of radiofrequency (RF) ablation for subcardiac and non-subcardiac hepatocellular carcinoma (HCC) and to evaluate the risk factors for technical failure of the procedure. METHODS: This retrospective study was approved by the institutional review board. Between September 2002 and May 2016, 73 patients with subcardiac HCC and the same number of patients with non-subcardiac HCC matched by tumor size were included. Subcardiac HCC was defined as an index tumor that was located ≤ 1 cm from the pericardium in axial or coronal images. Cumulative local tumor progression (LTP) was compared between the two groups using the log-rank test. Prognostic factors for technical failure were assessed using multivariable logistic analysis. RESULTS: Technical success rates between both groups were not significantly different (91.8% in the subcardiac HCC group vs. 95.9% in the non-subcardiac HCC group; p = 0.494). The cumulative LTP rates were 15.4% and 19.1% at 3 and 5 years, respectively, in the subcardiac HCC group, and 10.7% and 15.5% in the non-subcardiac HCC group, without significant difference (p = 0.862). The distance between the index tumor and pericardium (odds ratio [OR], 0.14; p = 0.023) and tumor in segment IV (reference, left lateral sector; OR, 36.53; p = 0.029) were significant factors for technical failure in patients with subcardiac HCC. CONCLUSIONS: RF ablation was an effective treatment for subcardiac HCC. However, tumor location should be considered in the planning of treatment to avoid technical failure. KEY POINTS: • RF ablation for subcardiac HCC is technically feasible without major complications. • RF ablation was an effective treatment for subcardiac HCC in terms of LTP. • Risk factors for technical failure were distance of the index tumor from the heart (cutoff value of 0.5 cm) and the location of the tumor (segment IV).

Differentiation of Hepatic Sclerosed Hemangiomas From Cavernous Hemangiomas Based on Gadoxetic Acid-Enhanced Magnetic Resonance Imaging Features.

OBJECTIVE: The objective of this study was to evaluate the imaging features of a hepatic sclerosed hemangioma by comparing them with those of a cavernous hemangioma using magnetic resonance imaging with gadoxetic acid enhancement. METHODS: Nine patients with hepatic sclerosed hemangiomas and 36 patients with cavernous hemangiomas (control group) who underwent gadoxetic acid-enhanced magnetic resonance imaging were included. Qualitative values (imaging findings and enhancement pattern [typical vs atypical enhancement]) and quantitative values (apparent diffusion coefficient) were evaluated. RESULTS: Patients with sclerosed hemangiomas showed significantly more irregular tumor margin on hepatobiliary phase images, peritumoral arterial enhancement, and a lower proportion of hyperintensity on heavily T2-weighted images compared with controls (all P values <0.05). In addition, the sclerosed hemangioma group had significantly more frequent atypical enhancement patterns than did the control group (88.9% vs 33.3%; P = 0.006). However, the mean apparent diffusion coefficient value of hemangiomas was not significantly different between the 2 groups (P = 0.639). CONCLUSIONS: Gadoxetic acid-enhanced magnetic resonance images can help in differentiating between hepatic sclerosed hemangiomas and cavernous hemangiomas.

Radiofrequency ablation vs. surgery for perivascular hepatocellular carcinoma: Propensity score analyses of long-term outcomes.

BACKGROUND & AIMS: The therapeutic outcomes of surgical resection (SR) or radiofrequency ablation (RFA) for perivascular hepatocellular carcinoma (HCC) have not been compared. The aim of this study was to compare SR with RFA as first-line treatment in patients with perivascular HCC and to evaluate the long-term outcomes of both therapies. METHODS: This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Between January 2006 and December 2010, a total of 283 consecutive patients with small perivascular HCCs (≤3 cm, Barcelona Clinic Liver Cancer stage 0 or A) underwent SR (n = 182) or RFA (n = 101) as a first-line treatment. The progression-free survival (PFS) and overall survival (OS) rates were compared by propensity score matching. Subgroup analysis of these outcomes was conducted according to the type of hepatic vessels. RESULTS: The median follow-up was 7.8 years. Matching yielded 62 pairs of patients. In the two matched groups, the PFS rates at 5 and 10 years were 58.0% and 17.8%, respectively, in the SR group, and 25.4% and 14.1%, respectively, in the RFA group (p <0.001). The corresponding OS rates at 5 and 10 years were 93.5% and 91.9% in the SR group and 82.3% and 74.1% in the RFA group, respectively (p <0.001). In contrast to those in patients with perivenous HCCs, subgroup analysis indicated that extrahepatic recurrence and OS were significantly different according to the treatment modality in patients with periportal HCCs (p = 0.004 and p <0.001, respectively). CONCLUSIONS: In patients with small perivascular HCCs, SR provided better long-term tumor control and OS than RFA, particularly for periportal tumors. LAY SUMMARY: Surgical resection and radiofrequency ablation are both treatment options for perivascular hepatocellular carcinoma. We compared outcomes in patients treated with either method. Surgical resection provided better long-term tumor control and overall survival than radiofrequency ablation for patients with a small perivascular hepatocellular carcinoma (≤3 cm) as a first-line treatment, particularly for periportal tumors. The location of the tumor and the type of peritumoral hepatic vessels need to be considered when choosing between surgical resection and radiofrequency ablation for small HCCs.