Using GPT-4 for LI-RADS feature extraction and categorization with multilingual free-text reports.

BACKGROUND AND AIMS: The Liver Imaging Reporting and Data System (LI-RADS) offers a standardized approach for imaging hepatocellular carcinoma. However, the diverse styles and structures of radiology reports complicate automatic data extraction. Large language models hold the potential for structured data extraction from free-text reports. Our objective was to evaluate the performance of Generative Pre-trained Transformer (GPT)-4 in extracting LI-RADS features and categories from free-text liver magnetic resonance imaging (MRI) reports. METHODS: Three radiologists generated 160 fictitious free-text liver MRI reports written in Korean and English, simulating real-world practice. Of these, 20 were used for prompt engineering, and 140 formed the internal test cohort. Seventy-two genuine reports, authored by 17 radiologists were collected and de-identified for the external test cohort. LI-RADS features were extracted using GPT-4, with a Python script calculating categories. Accuracies in each test cohort were compared. RESULTS: On the external test, the accuracy for the extraction of major LI-RADS features, which encompass size, nonrim arterial phase hyperenhancement, nonperipheral 'washout', enhancing 'capsule' and threshold growth, ranged from .92 to .99. For the rest of the LI-RADS features, the accuracy ranged from .86 to .97. For the LI-RADS category, the model showed an accuracy of .85 (95% CI: .76, .93). CONCLUSIONS: GPT-4 shows promise in extracting LI-RADS features, yet further refinement of its prompting strategy and advancements in its neural network architecture are crucial for reliable use in processing complex real-world MRI reports.

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.

Added Value of Pelvic CT after Treatment of HCC.

Background In patients with hepatocellular carcinoma (HCC) who undergo follow-up with CT after treatment, the benefit of routinely including pelvic coverage is not well substantiated. Purpose To investigate the added value of pelvic coverage at follow-up liver CT in detecting pelvic metastasis or incidental tumors in patients treated for HCC. Materials and Methods This retrospective study included patients who were diagnosed with HCC between January 2016 and December 2017 and followed up with liver CT after treatment. Cumulative rates of extrahepatic metastasis, isolated pelvic metastasis, and incidental pelvic tumor were estimated by using the Kaplan-Meier method. Cox proportional hazard models were used to identify risk factors for extrahepatic and isolated pelvic metastases. Radiation dose from pelvic coverage was also calculated. Results A total of 1122 patients (mean age, 60 years ± 10 [SD]; 896 men) were included. The cumulative rates at 3 years of extrahepatic metastasis, isolated pelvic metastasis, and incidental pelvic tumor were 14.4%, 1.4%, and 0.5%, respectively. At adjusted analysis, protein induced by vitamin K absence or antagonist-II (P = .001), size of the largest tumor (P = .02), T stage (P = .008), and initial treatment method (P < .001) were associated with extrahepatic metastasis. Only T stage was associated with isolated pelvic metastasis (P = .01). Because of pelvic coverage, the radiation dose increased by 29% and 39% in liver CT with and without contrast enhancement, respectively, compared with CT scans without pelvic coverage. Conclusion The incidence of isolated pelvic metastasis or incidental pelvic tumor was low in patients treated for hepatocellular carcinoma. © RSNA, 2023.

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.

Effect of Microvascular Invasion Risk on Early Recurrence of Hepatocellular Carcinoma After Surgery and Radiofrequency Ablation.

OBJECTIVE: We compared surgical resection (SR) and radiofrequency ablation (RFA) as first-line treatment in patients with hepatocellular carcinoma (HCC) based on the risk of microvascular invasion (MVI). BACKGROUND: The best curative treatment modality between SR and RFA in patients with HCC with MVI remains unclear. METHODS: Data from 2 academic cancer center-based cohorts of patients with a single, small (≤3 cm) HCC who underwent SR were used to derive (n = 276) and validate (n = 101) prediction models for MVI using clinical and imaging variables. The MVI prediction model was developed using multivariable logistic regression analysis and externally validated. Early recurrence (<2 years) based on risk stratification between SR (n = 276) and RFA (n = 240) was evaluated via propensity score matching. RESULTS: In the multivariable analysis, alpha-fetoprotein (≥15 ng/mL), protein induced by vitamin K absence-II (≥48 mAU/mL), arterial peritumoral enhancement, and hepatobiliary peritumoral hypointensity on magnetic resonance imaging were associated with MVI. Incorporating these factors, the area under the receiver operating characteristic curve of the predictive model was 0.87 (95% confidence interval: 0.82-0.92) and 0.82 (95% confidence interval: 0.74-0.90) in the derivation and validation cohorts, respectively. SR was associated with a lower rate of early recurrence than RFA based on the risk of MVI after propensity score matching (P < 0.05). CONCLUSIONS: Our model predicted the risk of MVI in patients with a small (≤ 3 cm) HCC with high accuracy. Patients with MVI who had undergone RFA were more vulnerable to recurrence than those who had undergone SR.

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.

Value of gadoxetic acid-enhanced MRI and diffusion-weighted imaging in the differentiation of hypervascular hyperplastic nodule from small (<3 cm) hypervascular hepatocellular carcinoma in patients with alcoholic liver cirrhosis: A retrospective case-control study.

BACKGROUND: Hypervascular hyperplastic nodules (HHNs) occasionally develop in patients with alcoholic liver cirrhosis (ALC) and show arterial enhancement, thus mimicking hepatocellular carcinoma (HCC). Importantly, HHN as a benign lesion should be distinguished from HCC. PURPOSE: To evaluate the value of gadoxetic acid-enhanced MRI (Gd-EOB-MRI) and diffusion-weighted imaging (DWI) in distinguishing HHN from small (<3 cm) hypervascular HCC (hHCC) in patients with ALC. STUDY TYPE: Retrospective case-control study. FIELD STRENGTH/SEQUENCE: 3.0T/in- and out-of-phase, T1 -weighted, T2 -weighted, diffusion-weighted, apparent diffusion coefficient, and dynamic gadoxetic acid-enhanced images. POPULATION: Among 560 patients with ALC who underwent Gd-EOB-MRI and DWI, 12 patients with 28 HHNs and 22 patients with 29 hHCCs smaller than 3 cm were included. ASSESSMENT: The following MRI features were evaluated by three independent radiologists: signal intensity (SI) on T1 -weighted, T2 -weighted, diffusion-weighted, and hepatobiliary phase (HBP) images; shape, homogeneity, and margin on HBP; diffusion restriction; intralesional fat; necrosis; hemorrhage; washout on portal venous phase (PVP) and/or transitional phase (TP); and capsular enhancement. Quantitative analysis was also conducted. STATISTICAL TESTS: Univariate and multivariate analyses were performed to determine the significant MRI findings, and their diagnostic performance for the prediction of HHN was analyzed. RESULTS: Lesion size of ≤16 mm (odds ratio [OR], 24.41; P = 0.007), low-to-iso SI on DWI (OR, 26.92; P = 0.007), and absence of washout on PVP and/or TP (OR, 31.84; P = 0.009) were significant independent factors for predicting HHN. When all three criteria were satisfied, the specificity was 100%. Compared with hHCCs, HHNs showed significantly smaller size (mean, 13.8 mm vs. 19.9 mm; P < 0.001) and higher mean SI value (994.0 vs. 669.5) and lesion-to-liver SI ratio (1.045 vs. 0.806) on HBP (P < 0.001, respectively). DATA CONCLUSION: Gd-EOB-MRI and DWI may be helpful in differentiating HHN from small hHCC in patients with ALC. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:70-80.

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.

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).

Non-contrast liver MRI as an alternative to gadoxetic acid-enhanced MRI for liver metastasis from colorectal cancer.

BACKGROUND: Liver magnetic resonance imaging (MRI) provides reliable diagnostic performance for detecting liver metastasis but is costly and time-consuming. PURPOSE: To compare the diagnostic performance of non-contrast liver MRI to whole MRI using gadoxetic acid for detecting liver metastasis in patients with colorectal cancer (CRC). MATERIAL AND METHODS: We included 175 patients with histologically confirmed 401 liver metastases and 73 benign liver lesions. A non-contrast MRI (T1-weighted, T2-weighted, and diffusion-weighted images) with or without multidetector computed tomography (MDCT) and a whole MRI (gadoxetic acid-enhanced and non-contrast MRI) were analyzed independently by two observers to detect liver metastasis using receiver operating characteristic analysis. RESULTS: We found no significant differences in Az value (range = 0.914-0.997), sensitivity (range = 95.2-99.6%), specificity (range = 77.3-100%), or positive (range = 92.9-100%) or negative predictive value (range = 87.5-95.7%) between the non-contrast MRI with or without MDCT and the whole MRI for both observers for all lesions as well as lesions ≤1.0 cm and lesions >1.0 cm in size ( P = 0.203-1.000). Combined MDCT and non-contrast MRI led to similar numbers of false-positive diagnosis to the whole MRI (eight for Observers 1 and 4 vs. 3 for Observer 2). CONCLUSION: Non-contrast liver MRI may serve as an alternative to gadoxetic acid-enhanced MRI for detecting and characterizing liver metastasis from CRC, at least in patients with relatively high risk of liver metastasis who underwent MDCT. Non-contrast liver MRI could be beneficial especially for patients with lesions that are already documented as benign but require additional follow-up MRIs.

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.

Percutaneous US/MRI Fusion-guided Radiofrequency Ablation for Recurrent Subcentimeter Hepatocellular Carcinoma: Technical Feasibility and Therapeutic Outcomes.

Purpose To evaluate the technical feasibility and therapeutic outcomes of percutaneous US/MRI fusion-guided radiofrequency ablation (RFA) of recurrent subcentimeter-sized hepatocellular carcinomas (HCCs). Materials and Methods For this retrospective study, between January 2012 and December 2014 a total of 194 planning US examinations were performed in 186 patients (159 men and 27 women; mean age, 61.1 years ± 10.0 [standard deviation]) for newly developed subcentimeter recurrent HCCs. These recurrent HCCs were defined as hypervascular nodules (>5.5 mm and <10 mm) with typical MRI findings of HCC. The study assessed how often US/MRI fusion-guided percutaneous RFA was deemed technically feasible at planning US examination (the feasibility rate) and the therapeutic outcomes after RFA, including the rates of technical success, technique efficacy, local tumor progression (LTP), and major complications. Cumulative LTP rates were estimated with the Kaplan-Meier method. Results The feasibility rate of percutaneous RFA at planning US examination was 65.7% (138 of 210 HCCs). The most common reason for RFA infeasibility was that an index tumor was inconspicuous at US. Among 138 subcentimeter HCCs feasible for RFA, 125 lesions underwent percutaneous RFA. The rates of both technical success and technique efficacy were 98.4% (123 of 125). The cumulative LTP rates at 1, 2, and 3 years were 3.6%, 5.4%, and 7.4%, respectively. The major complication rate was 2.5% (three of 119). Conclusion Percutaneous US/MRI fusion-guided radiofrequency ablation (RFA) was feasible in approximately two-thirds of subcentimeter recurrent hepatocellular carcinomas (HCCs). Percutaneous US/MRI fusion-guided RFA is a safe and effective treatment modality for patients with subcentimeter recurrent HCCs.

Indistinguishable T2/T3-N0 rectal cancer on rectal magnetic resonance imaging: comparison of surgery-first and neoadjuvant chemoradiation therapy-first strategies.

PURPOSE: We compared the treatment outcome between surgery-first and neoadjuvant chemoradiation therapy (nCRT)-first strategies in patients with indistinguishable T2/T3-N0 rectal cancer on rectal magnetic resonance imaging (MRI). METHODS: Our institutional review board approved this retrospective study, and informed consent was waived. Among 1910 patients who underwent rectal MRI between 2008 and 2012, 79 patients (mean age, 59.4 years, 49 men and 30 women) who had indistinguishable T2/T3-N0 rectal cancer on rectal MRI were included. Local recurrence-free survival (LRFS), recurrence-free survival (RFS), overall survival (OS), and disease-specific survival (DSS) were compared between the two groups. Treatment-related complications were evaluated. RESULTS: Among 79 patients, 51 were treated by surgery first and 28 were treated by nCRT first. In comparison of survival of the surgery- and nCRT-first groups at 5 years, the LRFS rate was 95.6 and 96.3%, RFS rate was 91.0 and 92.4%, OS rate was 93.7 and 92.6%, and DSS rate was 98.0 and 92.6%, respectively. LRFS, RFS, OS, and DSS showed no significant difference between the two groups (p = 0.862, 0.677, 0.953, and 0.479). The complication rate was not significantly different between the groups (20.0% for surgery-first group vs. 10.7% for nCRT-first group, p = 0.357). CONCLUSION: Treatment outcomes were not significantly different between surgery-first and nCRT-first strategies for indistinguishable T2/T3-N0 rectal cancer on rectal MRI.

Subcentimeter hypervascular nodules with typical imaging findings of hepatocellular carcinoma on gadoxetic acid-enhanced MRI: Outcomes of early treatment and watchful waiting.

OBJECTIVES: To compare treatment outcomes of subcentimeter hypervascular nodules at high risk for developing into hepatocellular carcinomas (SHNHR) between early treatment and watchful waiting until progression to overt hepatocellular carcinoma (HCC) groups. METHODS: SHNHRs were defined as subcentimeter hypervascular nodules with the usual imaging features of HCC on gadoxetic acid-enhanced magnetic resonance imaging (MRI). Among 63 patients with 74 SHNHRs, 27 (37 SHNHRs) received early treatment (treatment of < 1 cm nodules), and 36 (37 SHNHRs) underwent watchful waiting until progression to overt HCC. Risk factor analysis was performed for recurrence-free and local recurrence-free survival. RESULTS: Among the 36 patients who adopted watchful waiting, 33 eventually underwent treatment because their SHNHRs progressed to overt HCC. For recurrence-free survival, significant risk factors included number of previous treatments (HR, 1.181; p < 0.001), tumour number (HR, 1.943; p = 0.009), and α-feto protein level (HR, 1.005; p = 0.037) in the multivariate analyses. Treatment strategy was not a significant risk factor for recurrence-free survival. For local recurrence-free survival from the date of treatment, only treatment modality (transarterial chemoembolization) (HR, 6.879; p = 0.002) was a significant risk factor. CONCLUSION: Recurrence-free survival was not significantly different between early treatment and watchful waiting for SHNHRs. KEY POINTS: • Recurrence-free survival did not vary between the two treatment strategies. • Treatment modality was a significant factor for local recurrence-free survival. • Number of treatments, tumour number, and α-FP were risk factors for recurrence.

Liver Imaging Reporting and Data System on CT and gadoxetic acid-enhanced MRI with diffusion-weighted imaging.

OBJECTIVES: To assess major imaging features of Liver Imaging Reporting and Data System (LI-RADS) on contrast-enhanced CT and gadoxetic acid-enhanced MRI and to estimate whether the combination of signal intensity favouring HCC on hepatobiliary phase (HBP) and diffusion-weighted images (DWI) can act as a major feature in LI-RADS. METHODS: Four hundred twenty one patients with 445 observations were included. Major features of LI-RADS on CT and MRI as well as HBP and DWI features were assessed. Diagnostic performances of LR-5 according to LI-RADS v2014 and modified LI-RADS which incorporate combination of HBP and DWI were assessed. Pairwise comparisons of the receiver operating characteristic (ROC) curves were performed. RESULTS: For HCCs, capsule appearance had the highest rate of discordance between CT and MRI (32.7%), followed by washout appearance (22.2%). Specificity (75%) of LR-5 of LI-RADS v2014 was lower than that (77.1-79.2%) of modified LI-RADS. Area under the ROC curve of modified LI-RADS (0.755-0.775) was not significantly different from that of LI-RADS v 2014 (0.709) (p > 0.05). CONCLUSIONS: There were substantial discordances between CT and MRI for capsule and washout appearances in hepatic observations, and combination of gadoxetic acid-enhanced MRI and DWI might be able to be incorporated as a major feature of LI-RADS. KEY POINTS: • Major imaging features of LI-RADS showed substantial discordances on CT and MRI. • An observation may be categorized differently depending on used imaging exam. • CT and MRI should both be performed for LR-3 and LR-4 observations. • Combination of gadoxetic acid-enhanced MRI and DWI may be a major feature.

Disappearing or residual tiny (≤5 mm) colorectal liver metastases after chemotherapy on gadoxetic acid-enhanced liver MRI and diffusion-weighted imaging: Is local treatment required?

OBJECTIVES: To evaluate the clinical course of disappearing colorectal liver metastases (DLM) or residual tiny (≤5 mm) colorectal liver metastases (RTCLM) on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in patients who had colorectal liver metastases (CLM) and received chemotherapy. METHODS: Among 137 patients who received chemotherapy for CLM and underwent gadoxetic acid-enhanced MRI and DWI between 2010 and 2012, 43 patients with 168 DLMs and 48 RTCLMs were included. The cumulative in situ recurrence rate of DLM and progression rate of RTCLM and their predictive factors were evaluated. RESULTS: A total of 150 DLMs and 26 RTCLMs were followed up without additional treatment. At 1 and 2 years, respectively, the cumulative in situ recurrence rates for DLM were 10.9 % and 15.7 % and the cumulative progression rates for RTCLM were 27.2 % and 33.2 %. The in situ recurrence rate at 2 years was 4.9 % for the DLM group that did not show reticular hypointensity of liver parenchyma on hepatobiliary phase. CONCLUSIONS: DLM on gadoxetic acid-enhanced liver MRI and DWI indicates a high possibility of clinical complete response, especially in patients without chemotherapy-induced sinusoidal obstruction syndrome. Thirty-three percent of RTCLMs showed progression at 2 years. KEY POINTS: • DLMs on gadoxetic acid-enhanced MRI and DWI showed low recurrence rates. • If there is sinusoidal obstruction syndrome, evaluation of DLM needs special care. • The progression rate for residual tiny CLMs was 33.2 % at 2 years.

Intrahepatic distant recurrence after radiofrequency ablation for hepatocellular carcinoma: precursor nodules on pre-procedural gadoxetic acid-enhanced liver magnetic resonance imaging.

Background Intrahepatic distant recurrence (IDR) after radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) is associated with poor overall survival outcome. Purpose To evaluate the incidence and findings on pre-procedural gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) of precursor nodules for IDR after RF ablation for HCC. Material and Methods This study was approved by our institutional review board. Among 343 patients treated with RF ablation for HCC between 2009 and 2011, 141 patients who underwent pre-procedural gadoxetic acid-enhanced liver MRI and experienced IDR were enrolled. The presence of precursor nodules for IDR on pre-procedural imaging was assessed. Nodules were categorized based on hypervascularity in the arterial phase and signal intensity on hepatobiliary phase images. Time to recurrence was compared between patients with and without precursor nodules. Results In 46 (32.7%) of 141 patients (50 HCCs), there were precursor nodules on pre-procedural MRIs (median follow-up period, 4.39 years; range, 0.08-6.08). In three patients, HCCs were missed on imaging. In the remaining 43 patients, the 47 precursor nodules identified were non-hypervascular hypointense (n = 26), non-hypervascular isointense (n = 6), non-hypervascular hyperintense (n = 2), hypervascular hypointense (n = 10), and hypervascular isointense (n = 3). The mean time-to-recurrence was significantly shorter for patients with precursor nodules than for those without (16.6 versus 24.0 months, P = 0.011). Conclusion About one-third of patients with IDR after RF ablation for HCC had precursor nodules on pre-procedural gadoxetic acid-enhanced MRI, most commonly non-hypervascular hypointense nodules in the hepatobiliary phase.