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Background: Several ablation confirmation software methods for minimum ablative margin assessment have recently been developed to improve local outcomes for patients undergoing thermal ablation of colorectal liver metastases. Previous assessments were limited to single institutions mostly at the place of development. The aim of this study was to validate the previously identified 5 mm minimum ablative margin (A0) using autosegmentation and biomechanical deformable image registration in a multi-institutional setting., Methods: This was a multicentre, retrospective study including patients with colorectal liver metastases undergoing CT- or ultrasound-guided microwave or radiofrequency ablation during 2009-2022, reporting 3-year local disease progression (residual unablated tumour or local tumour progression) rates by minimum ablative margin across all institutions and identifying an intraprocedural contrast-enhanced CT-based minimum ablative margin associated with a 3-year local disease progression rate of less than 1%., Results: A total of 400 ablated colorectal liver metastases (median diameter of 1.5 cm) in 243 patients (145 men; median age of 62 [interquartile range 54-70] years) were evaluated, with a median follow-up of 26 (interquartile range 17-40) months. A total of 119 (48.9%) patients with 186 (46.5%) colorectal liver metastases were from international institutions B, C, and D that were not involved in the software development. Three-year local disease progression rates for 0 mm, >0 and <5 mm, and 5 mm or larger minimum ablative margins were 79%, 15%, and 0% respectively for institution A (where the software was developed) and 34%, 19%, and 2% respectively for institutions B, C, and D combined. Local disease progression risk decreased to less than 1% with an intraprocedurally confirmed minimum ablative margin greater than 4.6 mm., Conclusion: A minimum ablative margin of 5 mm or larger demonstrates optimal local oncological outcomes. It is proposed that an intraprocedural minimum ablative margin of 5 mm or larger, confirmed using biomechanical deformable image registration, serves as the A0 for colorectal liver metastasis thermal ablation., (© The Author(s) 2024. Published by Oxford University Press on behalf of BJS Foundation Ltd. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives: Evaluating the pathological response and the survival outcomes of combined thermal ablation (TA) and transarterial chemoembolization (TACE) as a bridge or downstaging for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) > 3 cm., Materials and Methods: A retrospective review encompassed 36 consecutive patients who underwent combined TA-TACE as bridging or downstaging before LT. Primary objectives included necrosis of the target lesion at explant pathology, post-LT overall survival (OS) and post-LT recurrence-free survival (RFS). For OS and RFS, a comparison with 170 patients subjected to TA alone for nodules <3 cm in size was also made., Results: Out of the 36 patients, 63.9% underwent TA-TACE as bridging, while 36.1% required downstaging. The average node size was 4.25 cm. All cases were discussed in a multidisciplinary tumor board to assess the best treatment for each patient. Half received radiofrequency (RF), and the other half underwent microwave (MW). All nodes underwent drug-eluting beads (DEB) TACE with epirubicin. The mean necrosis percentage was 65.9% in the RF+TACE group and 83.3% in the MW+TACE group (p-value = 0.099). OS was 100% at 1 year, 100% at 3 years and 94.7% at 5 years. RFS was 97.2% at 1 year, 94.4% at 3 years and 90% at 5 years. Despite the different sizes of the lesions, OS and RFS did not show significant differences with the cohort of patients subjected to TA alone., Conclusions: The study highlights the effectiveness of combined TA-TACE for HCC>3 cm, particularly for bridging and downstaging to LT, achieving OS and RFS rates significantly exceeding 80% at 1, 3 and 5 years., (© 2024. The Author(s).)

Locoregional treatments, as alternatives to surgery, play a key role in the management of hepatocellular carcinoma (HCC). Liver magnetic resonance imaging (MRI) enables a multiparametric assessment, going beyond the traditional dynamic computed tomography approach. Moreover, the use of hepatobiliary agents can improve diagnostic accuracy and are becoming important in the diagnosis and follow-up of HCC. However, the main challenge is to quickly identify classical responses to loco-regional treatments in order to determine the most suitable management strategy for each patient. The aim of this review is to provide a summary of the most common and uncommon liver MRI findings in patients who underwent loco-regional treatments for HCC, with a special focus on ablative therapies (radiofrequency, microwaves and cryoablation), trans-arterial chemoembolization, trans-arterial radio-embolization and stereotactic ablative radiotherapy techniques, considering the usefulness of gadoxetate disodium (Gd-EOB-DTPA) contrast agent., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)

Objectives: Oligometastatic colorectal cancer benefits of locoregional treatments but data concerning microwave ablation (MWA) are limited and interactions with systemic therapy are still debated. The aim of this study is to evaluate safety and effectiveness of Thermosphere™ MWA (T-MWA) of colorectal liver metastases (CLM) and factors affecting local tumor progression-free survival (LTPFS)., Methods: In this multi-institutional retrospective study (January 2015-September 2019), patients who underwent T-MWA for CLM were enrolled. Complications according to SIR classification were collected, primary efficacy and LTP were calculated. Analyzed variables included CLM size at diagnosis and at ablation, CLM number, ablation margins, intra-segment progression, chemotherapy before ablation (CBA), variations in size (ΔS DIA-ABL ), and velocity of size variation (V DIA-ABL ) between CLM diagnosis and ablation. Uni/multivariate analyses were performed using mixed effects Cox model to account for the hierarchical structure of data, patient/lesions., Results: One hundred thirty-two patients with 213 CLM were evaluated. Complications were reported in 6/150 procedures (4%); no biliary complications occurred. Primary efficacy was achieved in 204/213 CLM (95.7%). LTP occurred in 58/204 CLM (28.4%). Six-, twelve-, and eighteen-month LTPFS were 88.2%, 75.8%, and 69.9%, respectively. At multivariate analysis, CLM size at ablation (p = 0.00045), CLM number (p = 0.046), ablation margin < 5 mm (p = 0.0035), and intra-segment progression (p < 0.0001) were statistically significant for LTPFS. ΔS DIA-ABL (p = 0.63) and V DIA-ABL (p = 0.38) did not affect LTPFS. Ablation margins in the chemo-naïve group were larger than those in the CBA group (p < 0.0001)., Conclusion: T-MWA is a safe and effective technology with adequate LTPFS rates. Intra-segment progression is significantly linked to LTPFS. CBA does not affect LTPFS. Anticipating ablation before chemotherapy may take the advantages of adequate tumor size with correct ablation margin planning., Key Points: • Thermosphere™-Microwave ablation is a safe and effective treatment for colorectal liver metastases with no registered biliary complications in more than 200 ablations. • Metastases size at time of ablation, intra-segment progression, and minimal ablation margin < 5 mm were found statistically significant for local tumor progression-free survival. • Chemotherapy before ablation modifies kinetics growth of the lesions but deteriorates ablation margins and does not significantly impact local tumor progression-free survival., (© 2022. The Author(s).)

Objectives: To investigate the predictive value of four-phase contrast-enhanced CT (CECT) for early complete response (CR) to drug-eluting-bead transarterial chemoembolization (DEB-TACE), with a particular focus on the quantitatively assessed wash-in and wash-out., Methods: A retrospective analysis of preprocedural CECTs was performed for 129 HCC nodules consecutively subjected to DEB-TACE as first-line therapy. Lesion size, location, and margins were recorded. For the quantitative analysis, the following parameters were computed: contrast enhancement ratio (CER) and lesion-to-liver contrast ratio (LLC) as estimates of wash-in; absolute and relative wash-out (WO abs and WO rel ) and delayed percentage attenuation ratio (DPAR) as estimates of wash-out. The early radiological response of each lesion was assessed by the mRECIST criteria and dichotomized in CR versus others (partial response, stable disease, and progressive disease)., Results: All quantitatively assessed wash-out variables had significantly higher rates for CR lesions (WO abs p = 0.01, WO rel p = 0.01, and DPAR p = 0.00002). However, only DPAR demonstrated an acceptable discriminating ability, quantified by AUC = 0.80 (95% CI0.73-0.88). In particular, nodules with DPAR ≥ 120 showed an odds ratio of 3.3(1.5-7.2) for CR (p = 0.0026). When accompanied by smooth lesion margins, DPAR ≥ 120 lesions showed a 78% CR rate at first follow-up imaging. No significative association with CR was found for quantitative wash-in estimates (CER and LLC)., Conclusions: Based on preprocedural CECT, the quantitative assessment of HCC wash-out is useful in predicting early CR after DEB-TACE. Among the different formulas for wash-out quantification, DPAR has the best discriminating ability. When associated, DPAR ≥ 120 and smooth lesion margins are related to relatively high CR rates., Key Points: • A high wash-out rate, quantitatively assessed during preprocedural four-phase contrast-enhanced CT (CECT), is a favorable predictor for early radiological complete response of HCC to drug-eluting-bead chemoembolization (DEB-TACE). • The arterial phase of CECT shows great dispersion of attenuation values among different lesions, even when a standardized protocol is used, limiting its usefulness for quantitative analyses. • Among the different formulas used to quantify the wash-out rate (absolute wash-out, relative wash-out, and delayed percentage attenuation ratio), the latter (DPAR), based only on the delayed phase, is the most predictive (AUC = 0.80), showing a significant association with complete response for values above 120., (© 2021. The Author(s).)

Purpose: To evaluate the features of arterial enhancement pattern of focal nodular hyperplasia (FNH) and hepatocellular carcinoma (HCC) by triple-phase arterial magnetic resonance imaging (MRI)., Methods: Data were retrospectively collected from 52 consecutive patients who underwent triple-phase arterial MRI using hepatocyte-specific contrast agents (Gd-EOB-DTPA) from January 2017 to October 2017, with a MR imaging diagnosis of HCC or FNH. The images were independently assessed by two blinded readers. Contrast enhancement ratio (CER) and liver-to-lesion contrast ratio (LLCR) were calculated. The lesions were classified visually and also based on the peak of LLCR into the following groups: (1) early arterial, (2) middle arterial and (3) late arterial. Data were eventually analysed using nonparametric tests., Results: The CER analysis showed no significant difference between HCC and FNH patients (p > 0.05). LLCR FNH were significantly higher than LLCR HCC in the early arterial (p = 0.01), but not in the middle and late arterial phases (p = 0.20 and p = 0.82, respectively). LLCR HCC presented a meaningful increase from early to middle arterial phase (p = 0.009), whereas LLCR FNH showed a decrease from middle to late arterial phase (p = 0.004). Based on the peak of LLCR, 17 (55%) FNHs were classified into early, 11 (35%) in middle and only 3 (10%) in late arterial phase groups. Similarly, 14 (34%) HCCs were categorized into early, 13 (32%) in middle and 14 (33%) in late arterial phase groups. There was a good agreement between qualitative analysis and LLCR in 85% of cases., Conclusion: The optimal visualization of FNH has been detected in early and middle arterial phases while HCC has been best observed during middle and late arterial phases.

Aim: Evaluating clinical and technical factors affecting thermal ablation of B-Mode/CEUS inconspicuous HCC nodules, relying only on fusion imaging (FI) performed under conscious sedation and using previously acquired CT or MR., Materials and Methods: Among 367 HCC nodules treated in the study period, data of 37 B-mode/CEUS undetectable HCC nodules treated with FI-guided ablation were extracted from our prospectively collected institutional database. Analyzed variables included patients' sex, age, cirrhosis etiology, Child-Pugh status, size of the lesion, liver segment, subcapsular or central liver site, type of imaging used for fusion (MR/CT), and the presence of surrounding anatomical landmarks (SAL) < 3 cm from the index lesion., Results: The primary efficacy was 59.4% (22/37 nodules); nine lesions (24.3%) were partially ablated (PA), six lesions (16.7%) were mistargeted (MA). Eight nodules were retreated with a CA obtained in all cases (100% CA, secondary efficacy in 30/37-81.1%). LTP was observed in 2/30 cases (6.7%). Two minor complications were registered (Clavien-Dindo, Grade1, CIRSE Classification Grade 2). SAL were related to a better ablation outcome (37.5% vs 84.6% p = 0.01). No differences were observed between CA group and PA-MA group in terms of lesion size (15.4 mm vs 14.9 mm p = 0.63), liver segment (p = 0.58), subcapsular or central liver site (8/22 36% vs 4/15 26.7% p = 0.84), and imaging (MR vs CT, p = 0.72)., Conclusion: Even in the presence of potentially critical conditions (completely B-Mode/CEUS inconspicuous nodules, spontaneous breathing, and previously acquired CT or MRI), FI-only guidance is safe and allows having good primary, secondary efficacy and LTP rates. The outcome of the procedure is heavily affected by the presence of SAL.

As medical imaging advancements have improved the detectability of hepatocellular carcinoma (HCC) in early stages, the approach to percutaneous thermal ablation for curative treatment has concomitantly advanced. Although many centers are adopting cross-sectional imaging to guide percutaneous ablation, the majority of procedures are still performed under ultrasound (US) guidance worldwide. Challenges to ultrasound guidance may present due to relatively poor resolution particularly with small or isoechoic lesions, or due to intervening structures such as the bowel or diaphragm that obstruct lesional visualization. Fusion imaging (FI) systems have been employed to address these challenges. By merging or synchronizing the real-time images from US with a previously obtained cross-sectional study, FI mitigates the inherent limitations of each individual imaging modality and expands procedural feasibility and technical outcomes. This manuscript reviews the current literature on the use of FI during percutaneous thermal ablation of HCC.

Aims: To evaluate motion artifacts, breath-hold failure, acute transient dyspnea, and clinical parameters during hepatic arterial phase of gadoxetate disodium-enhanced magnetic resonance (MR) imaging., Methods: This was an institutional review board-approved observational prospective study (written informed consent acquired) performed in 250 consecutive patients, who underwent liver MR with a multiarterial phase technique. Oxygen saturation (SatO 2 ) and heart rate (HR) were monitored, while patients reported subjective symptoms. Breath-holds were assessed using prospective acquisition correction technique (PACE) monitors. Three readers independently analyzed all images to establish the presence of motion artifacts. Nonparametric statistical testing and Fleiss' kappa were used., Results: No statistical differences in SatO 2 and HR values were observed during the entire length of MR examination. The PACE graphs showed an altered breath-hold in 16/250 patients (6.4%), however only 6 patients self-reported symptoms during the procedure, and among these 6 subjects, only 2 suffered from acute transient dyspnea (0.8%). Motion-related artifacts increased mostly in the third arterial phase of gadoxetate disodium acquisition (p < 0.0001): The artifacts incidence was 2.9% in the first phase; 4.0% in the second; and 19.5% in the third. This increase was mainly due to patients' inability to hold their breath for the entire duration of the examination. However, at least one gadoxetate disodium arterial phase without motion artifacts and adequate for acquisition timing, was acquired in all MR examinations., Conclusion: The incidence of breath-hold failure and acute transient dyspnea after gadoxetate disodium administration increased during the third arterial phase only. Our protocol allowed the acquisition of at least one arterial phase not compromised by motion artifacts and adequate for acquisition timing, in all patients.

Objectives: To investigate effects of ablation margins on local tumour progression-free survival (LTPFS) according to RAS status in patients with colorectal liver metastases (CLM)., Methods: This two-institution retrospective study from 2005-2016 included 136 patients (91 male, median age 60 years) with 218 ablated CLM. LTPFS was performed using the Kaplan-Meier method and evaluated with the log-rank test. Uni/multivariate analyses were performed using Cox-regression models., Results: Three-year LTPFS rates for CLM with minimal ablation margin ≤10 mm were significantly worse than those with >10 mm in both mutant-RAS (29% vs. 48%, p=0.038) and wild-type RAS (70% vs. 94%, p=0.039) subgroups. Three-year LTPFS rates of mutant-RAS were significantly worse than wild-type RAS in both CLM subgroups with minimal ablation margin ≤10 mm (29% vs. 70%, p<0.001) and >10 mm (48% vs. 94%, p=0.006). Predictors of worse LTPFS were ablation margins ≤10 mm (HR: 2.17, 95% CI 1.2-4.1, p=0.007), CLM size ≥2 cm (1.80, 1.1-2.8, p=0.017) and mutant-RAS (2.85, 1.7-4.6, p<0.001)., Conclusions: Minimal ablation margin and RAS status interact as independent predictors of LTPFS following CLM ablation. While minimal ablation margins >10 mm should be always the procedural goal, this becomes especially critical for mutant-RAS CLM., Key Points: • RAS and ablation margins are predictors of local tumour progression-free survival. • Ablation margin >10 mm, always desirable, is crucial for mutant RAS metastases. • Interventional radiologists should be aware of RAS status to optimize LTPFS.

Background: The aim of this study was to evaluate the safety and efficacy of percutaneous ablation for hepatocellular carcinoma (HCC) hepatic recurrence along surgical resection margins to achieve complete cure or bridge for additional treatment. No current recommendations exist for these lesions., Methods: Retrospective review of post-surgical recurrent HCC located along surgical margins treated by percutaneous ultrasound-guided ablation from 2006-2014. Ablation was performed by radiofrequency ablation (RFA) or percutaneous ethanol injection (PEI), selected for recurrence in proximity to extrahepatic organs., Results: In total, nine patients (49-82 y, mean 73.8±8.3) were treated for 13 recurrent HCC nodules (9-35 mm, mean 21.5±8.1) located along resection margins by RFA (11 nodules) and PEI (2 nodules). Mean time between surgery and percutaneous ablation was 64 months (range 10-149). At a mean follow-up of 17 months (±9), complete ablation was achieved in 9 nodules (69.2%, 8 after RF, 1 after PEI) and partial ablation was achieved in 4 nodules (3 after RFA, 1 after PEI). Complications were limited to minor abdominal pain in 2 patients requiring medical therapy (15.3%). Of the 4 partially ablated nodules, subsequent therapy achieved complete response in 3 nodules (1 patient with TACE, 1 patient with stereotactic radiotherapy, and one with liver transplantation), while the last nodule progressed despite subsequent TACE., Conclusions: HCC recurrence along the surgical margin can be safely and effectively treated by percutaneous therapy, despite the misconception of the surgical margin as a hostile location. Percutaneous treatment may bridge the patient for additional therapy.

Purpose: To compare MWA and RFA combined with TACE for HCC nodules exceeding 3 cm., Methods: 19 lesions submitted to MWA (G1) were retrospectively compared with a combined treatment group (G2) matching by tumor characteristics (mean size 43 and 45 mm in G1 and G2, respectively). Technical success, complications, complete ablation (CA), and maintained CA (mCA) were evaluated., Results: Technical success was achieved in all cases. Overall mortality was zero, both in G1 and G2. No significant differences were found in complications rates (3 in G1 and 2 in G2). CA was obtained in 11 (58 %) HCC in G1 and 15 (79 %) in G2 (p = n.s.). CA was obtained in 75.5 % (G1) and 89 % (G2) nodules up to 4 cm, 45 % and 70 % nodules >4 cm, respectively. At statistical analysis, size resulted as predictor for CA only in G1 (mean diameter of CA vs non-CA 39.9 vs. 47.7 mm, p = 0.021). During follow-up (13.1 and 14.4 months in G1 and G2), mCA occurred in 6/19 (32 %) nodules in G1, 8/19 (42 %) in G2., Conclusion: MWA and combined therapy are comparable as for safety. No significant differences were found in terms of technique effectiveness. Larger randomized studies should be designed to confirm MWA as a valid alternative to combined therapy.

Purpose: To evaluate Gd-EOB-DTPA-enhanced magnetic resonance (MR) performance during dynamic (DYN) phases, hepatobiliary (HB) phase and diffusion-weighted imaging (DWI) compared with pathological findings in patients undergoing orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC) associated with different conditions, such as stage of chronic liver disease, histological grading, nodule size, and occurrence of previous treatments., Methods: Retrospective analysis of 64 nodules reported as HCC at pathological analysis on 28 explanted livers, examined about 3 months before OLT using a 1.5 T device and 16 channels array after intravenous GD-EOB-DTPA injection. Lesions features and hepatic functional values were recorded for each patient. Two radiologists performed in consensus the analysis of nodules on DYN, HB, and DWI. MR findings were compared with those of pathological anatomy. Diagnostic indicators were calculated for each technique., Results: DYN and HB showed no statistically significant difference in sensitivity (88% and 98%, respectively), diagnostic accuracy (90.6% and 99.9%), and specificity (both 100%), for all Child-Pugh scores, gradings, sizes, and presence or absence of previous treatments. DWI had a statistically significant lower sensitivity compared to DYN (p = 0.001) and HB (p < 0.0001); its sensitivity was significantly inferior for Child-Pugh Class B nodules than for Child-Pugh Class A ones (p = 0.00005). DWI sensitivity presented a significant increase (p = 0.03) with grading and presence of previous treatments (p = 0.0006). ADC values showed no statistically significant changes with Child-Pugh score, grading and nodules size; statistically significant increase was instead found for treated vs. untreated nodules (p = 0.016)., Conclusions: In a multiparametric HCC MRI assessment, DYN and HB play the leading role, with DWI faring acceptably well for Child-Pugh Class A nodules and treated ones.

Purpose: This paper discusses the technique and preliminary results of right thoracic paravertebral block (TPVB) for percutaneous thermal ablation of liver tumours., Materials and Methods: Between October 2011 and August 2012 we treated 36 lesions (25 hepatocellular carcinoma and 11 metastases) in 30 patients aged 47-85 years (mean 67.5). Patients received ultrasound (US)-guided injection of 7 ml of naropin 0.75 % in T7, T9 and T11 levels, below the costo-vertebral ligament, until we observed an anterior displacement of the parietal pleura. For the subcapsular lesions, a cervical right phrenic nerve block was associated. The level of analgesia was evaluated during and after the percutaneous procedures with the Numerical Rating Scale. Finally, we investigated statistical correlations between pain and lesions (histological type, site, dimensions), and ablation time and technique (microwave or radiofrequency ablation)., Results: Technical success was achieved in all patients. Despite the correct anaesthetic diffusion during the ablation, 10 patients (33.3 %) reported medium/severe pain and intravenous sedation was required. Pain was not found to correlate with any variable. No complications were observed., Conclusions: In most cases, TPVB is a safe and effective technique for conscious anaesthesia during percutaneous thermal ablation of liver tumours. Failures probably derive from left sympathetic and parasympathetic fibre stimulation. We recommend performing a TPVB in the presence of the anaesthetist.