Liver Ablation Research Articles

Tailoring ablation strategies for colorectal liver metastases based upon rat sarcoma viral oncogene mutation status

Rat sarcoma viral oncogene (RAS) is one of the most well-known tumor genes implicated in the oncological and surgical management of patients with colorectal liver metastases (CLM). More recently, RAS mutational status has also emerged as a relevant factor affecting the oncological outcomes of CLM treated with ablation procedures, a well-established local therapy modality routinely utilized in the oligometastatic disease (OMD) setting. Available evidence suggests that RAS mutation is a prognosticator of shorter local tumor progression free survival (LTPFS) following liver ablation, and that mutant RAS patients with CLM treated with ablation should have wider minimal ablation margins. In this review, we aim to discuss the current literature on the influence of RAS mutational status on ablation outcomes, as well to provide a perspective on the future research on the impact of tumor molecular biology on liver ablation procedures and the potential synergies between local and systemic therapies.

Electromagnetic navigation to assist with computed tomography-guided thermal ablation of liver tumors

Purpose: To evaluate the advantages and primary technical efficacy of an electromagnetic (EM) navigation system for computed tomography (CT)-guided thermal ablation of liver tumors.Material and methods: From August 2016 to January 2018, 40 patients scheduled for CT- guided thermal ablation were prospectively enrolled and divided into two groups. Twenty patients underwent CT-guided thermal ablation with an EM navigation system (navigation group), while the other 20 patients underwent conventional CT-guided thermal ablation (control group). Data on skin punctures, instrument adjustments, puncture time to target, CT scans, CT fluoroscopy time and dose-length-product (DLP) were compared between the two groups. Any postoperative complications were recorded and the primary technical efficacy was evaluated four to six weeks after the procedure.Results: All 20 patients in the navigation group successfully underwent EM navigation. Compared to the control group, there were fewer instrument adjustments (mean 2.40 vs. 4.95; p = .003), fewer CT scans (mean 7.10 vs. 10.30; p = .006), less CT fluoroscopy time (mean 40.47 vs. 59.98 s, p = .046), and less DLP (mean 807.39 vs. 1578.67 mGy × cm; p = .001). Although not statistically significant, EM navigation resulted in fewer skin punctures (mean 1.20 vs. 1.25; p = .803) and slightly longer puncture time to target (mean 16.50 vs. 15.20 min; p = .725). No patients experienced major complications and the primary efficacy rate was 90% and 84.21% in the navigation and control groups, respectively (p = .661).Conclusions: EM navigation system optimizes the thermal ablation process and reduces radiation exposure in patients. However, further studies are warranted to determine whether an EM navigation system can improve procedure time, complication rates, and primary technical efficiacy of thermal ablation.

Current Trends in the Surgical Management of Colorectal Cancer Liver Metastases

Cancers of colorectal origin are the second leading cause of cancer-related deaths in the USA, and with the improvements in chemotherapy and other therapeutic modalities, there are more options for the management of metastatic disease. The liver is the most common site of colorectal metastasis, and treating the disease to the liver may lead to prolonged survival and possible cure. Our understanding of tumor biology and the refinement of surgical techniques have resulted in significantly improved outcomes. The treatment of colorectal liver metastasis is complex and thus requires a multidisciplinary approach. There is increasing body of literature that points towards more aggressively selective and personalized surgical treatment of colorectal cancer liver metastases. New techniques like hepatic artery infusion, liver chemoperfusion, operative and transcutaneous liver ablation with microwave, radiofrequency or irreversible electroporation have resulted in significantly improved outcomes. There is significant progress in the surgical management of liver metastasis of colorectal origin, with improved outcomes in patients that otherwise would be candidates only for palliative chemotherapy. More and exciting research is underway in order to appreciate the impact of newer techniques.

Results after simultaneous surgery and RFA liver ablation for patients with colorectal carcinoma and synchronous liver metastases

BackgroundApproximately 20% of patients with colorectal cancer present with synchronous liver metastases (sCRLM). These patients can be treated with a “one-step procedure” or staged resection, with or without radiofrequency ablation (RFA). Colorectal surgery in combination with intraoperative RFA leads to concerns regarding postoperative complications and survival. The purpose was to evaluate the one-step procedure with or without RFA in patients with sCRLM. Materials and methodsBetween January 2000 and September 2018, patients with sCRLM were selected in two tertiary referral centers and retrospectively analyzed. Postoperative morbidity and survival were analyzed. ResultsFrom a total of 410 patients presenting with sCRLM, 329 patients underwent a staged resection and 81 a one-step procedure. The 3-year overall survival (OS) was respectively 66% and 69% for one-step procedure and staged resection (P = 0.24). A total of 18 patients underwent RFA during the one step procedure. No significant differences were shown in postoperative complications whether intraoperative RFA was used in patients with sCRLM. In the one-step procedure, the 3-year OS was respectively 43% and 72% wheter patients did or did not receive RFA (P = 0.19). ConclusionOS for patients with sCRLM was similar for both one-step procedure and staged resection. Intraoperative RFA for sCRLM is technically safe.

High Frequency Jet Ventilation during stereotactic ablation of liver tumours: an observational study on blood gas analysis as a measure of lung function during general anaesthesia

Background: Stereotactic ablation of tumours in solid organs is a promising curative procedure in clinical oncology. The technique demands minimal target organ movements to optimise tumour destruction and prevent injury to surrounding tissues. High frequency jet ventilation (HFJV) is a novel option during these procedures, reducing the respiratory-associated movements of the liver. The effects of HFJV via endotracheal catheter on gas exchange during liver tumour ablation is not well studied. Methods: The aim of this explorative study was to assess lung function and the effects on blood gas and lactate during HFJV in patients undergoing stereotactic liver ablation. Blood gases were analysed in 25 patients scheduled for stereotactic liver ablation under general anaesthesia pre-induction, every 15 minutes during HFJV and following extubation in the recovery room. The HFJV was set at fixed settings. Results: None of the patients developed hypoxia or signs of increased lactate production but a great variation in PaO 2/FiO 2 ratio was found; from 13.1 to 71.3. An increase in mean PaCO 2 was observed, from a baseline of 5.0 to a peak of 7.1 at 30 minutes (p <0.001) and a decrease was found in median pH, from a baseline of 7.44 to 7.31 at 15 minutes (p=0.03). We could not see any clear association between a decrease in PaO 2/FiO 2 ratio and PaCO 2 elevation. Conclusions: HFJV during general anaesthesia in patients undergoing stereotactic liver ablation is feasible and it did not cause hypoxemia or signs of increased lactate production. A reversible mild to moderate impairment of gas exchange was found during HFJV.

Combined Treatments in Liver Ablations

AbstractPercutaneous ablation is a curative treatment indicated in very early and early hepatocellular carcinoma (HCC). Procedural success remains disappointing in lesions ≥3.0 cm and located in subcapsular and perivascular areas. To overcome these limitations, combination treatments have been proposed. The combination of ablation and transarterial chemoembolization (TACE) is widely adopted in clinical practice and may improve survival, particularly in patients with single nodules 3 to 5 cm in size. However, technical issues and clinical indications are still debated. Radiofrequency ablation (RFA) may also be combined with percutaneous ethanol injection to improve local tumor control; limited data show safety and efficacy of this option. The combination of ablation and systemic treatments is still debated. Intravenous injection of thermosensitive liposomal doxorubicin in association with prolonged RFA is under investigation in patients with single lesions &lt; 7 cm. While there is no indication for the use of systemic drugs (specifically sorafenib) in the adjuvant setting, the observation that RFA is able to activate inflammatory reactions has raised interest in the possibility of combining RFA with the new immuno-oncology drugs, for local and distant tumor control. Thus ablation would no longer be reserved only to early HCC but could be exploited also in more advanced stages.

Laparoscopic Multiple Parenchyma-sparing Concomitant Liver Resections for Colorectal Liver Metastases.

Parenchyma-sparing concept in liver surgery has received a new incitement with the introduction of laparoscopic techniques. Multiple concomitant liver resections are a major component in the parenchyma-sparing concept. In total, 689 patients underwent laparoscopic liver resection for colorectal liver metastases from August 1998 to 2017, and 171 patients were eligible for this study. Patients were divided into 3 groups: group I with single liver resection (36 patients); group II with multiple concomitant liver resections (104 patients); group III with liver resection(s) combined with concomitant liver ablation (31 patients). Perioperative outcomes and survival were compared between the groups I and II, whereas variables of group III were presented as complementary information, avoiding statistically exigent multiple comparisons. There were 6 conversions, 0, 3 (2.9%), and 2 (6.5%), respectively in the groups I, II, and III. Median operative time was 161, 186, and 224 minute in the groups I, II, and III, respectively. Median blood loss was 300 mL in groups I and II, and 200 mL in group III. It was a tendency to higher rate of postoperative complications in the group of single resections with morbidity rate of 31%, 19%, and 23% in group I, II, and III, respectively. Median postoperative stay was 3 days in all groups. Tumor-free margin resection was achieved in 92%, 86%, and 93%, respectively in the groups I, II, III. The median weight of resected specimen was significantly lower in group II (90 vs. 257 g; P<0.001). There were no significant differences in survival between the groups. The 5-year overall survival was 31%, 42%, and 43% for groups I, II, and III, respectively. Laparoscopic multiple concomitant parenchyma-sparing liver resections provide surgical and oncologic outcomes comparable with single greater resections for multiple lesions. This approach could be recommended for a wide application in specialized hepatopancreatobiliary centers.

Focused Ultrasound Effects on Osteosarcoma Cell Lines.

MRI guided Focused Ultrasound (MRgFUS) has shown to be effective therapeutic modality for non-invasive clinical interventions in ablating of uterine fibroids, in bone metastasis palliative treatments, and in breast, liver, and prostate cancer ablation. MRgFUS combines high intensity focused ultrasound (HIFU) with MRI images for treatment planning and real time thermometry monitoring, thus enabling non-invasive ablation of tumor tissue. Although in the literature there are several studies on the Ultrasound (US) effects on cell in culture, there is no systematic evidence of the biological effect of Magnetic Resonance guided Focused Ultrasound Surgery (MRgFUS) treatment on osteosarcoma cells, especially in lower dose regions, where tissues receive sub-lethal acoustic power. The effect of MRgFUS treatment at different levels of acoustic intensity (15.5-49 W/cm2) was investigated on Mg-63 and Saos-2 cell lines to evaluate the impact of the dissipation of acoustic energy delivered outside the focal area, in terms of cell viability and osteogenic differentiation at 24 h, 7 days, and 14 days after treatment. Results suggested that the attenuation of FUS acoustic intensities from the focal area (higher intensities) to the “far field” (lower intensities) zones might determine different osteosarcoma cell responses, which range from decrease of cell proliferation rates (from 49 W/cm2 to 38.9 W/cm2) to the selection of a subpopulation of heterogeneous and immature living cells (from 31.1 W/cm2 to 15.5 W/cm2), which can clearly preserve bone tumor cells.

Complications from percutaneous microwave ablation of liver tumours: a pictorial review.

Percutaneous microwave ablation of liver tumours is a well-established technique that has been proven to be effective in the curative and palliative treatment of small volume primary and secondary liver tumours. Microwave ablation is designed to achieve larger areas of necrosis compared to radiofrequency ablation and has a good safety profile among liver tumour treatments. Mortality is unreported and major complications are rare. Knowledge of potential complications is essential for interventional radiologists performing liver ablation in order to reduce patient morbidity. The aim of this review is to illustrate major complications post microwave ablation in a pictorial format as well as a discussion on how best to avoid these complications.

Intra-arterial Mitomycin C infusion in a large cohort of advanced liver metastatic breast cancer patients: safety, efficacy and factors influencing survival.

The aim of this study was to determine the safety and efficacy of Mitomycin C (MMC) infusion in a large cohort of advanced liver metastatic breast cancer patients (LMBC) and to determine factors influencing overall survival (OS). We retrospectively analysed LMBC patients, treated with MMC infusion between 2000 and 2017. Hepatic response was measured with baseline CT scans and first available CT scan after MMC infusion by RECIST 1.1 criteria. Adverse events were registered by the CTCAE version 5.0. OS and hepatic progression free survival (hPFS) were evaluated using Kaplan-Meier estimates. After univariable analysis, a stepwise forward multivariable (MV) prediction analysis was developed to select independent pre-treatment factors associated with OS. We included 176 patients with a total of 599 MMC infusions, mostly heavily pre-treated patients with a median time from diagnosis of MBC to MMC infusion of 36.9months. RECIST evaluation of liver lesions (n = 132) showed a partial response rate of 15%, stable disease of 43% and progressive disease in 17%. Adverse events grade 3 and 4 were reported in 17.5%. Median PFS was 5.5months and median OS was 7.8months. Significant independent baseline predictors of worse OS included number of prior systemic chemotherapy lines, prior liver ablation, higher liver tumour burden and elevated levels of bilirubin and ALT. MMC infusion is safe and effective in advanced LMBC patients. An increased number of prior therapies, a higher liver tumour burden and elevated levels of bilirubin and ALT were associated with a worse OS.

Three-dimensional therapy needle applicator segmentation for ultrasound-guided focal liver ablation.

Minimally invasive procedures, such as microwave ablation, are becoming first-line treatment options for early-stage liver cancer due to lower complication rates and shorter recovery times than conventional surgical techniques. Although these procedures are promising, one reason preventing widespread adoption is inadequate local tumor ablation leading to observations of higher local cancer recurrence compared to conventional procedures. Poor ablation coverage has been associated with two-dimensional (2D) ultrasound (US) guidance of the therapy needle applicators and has stimulated investigation into the use of three-dimensional (3D) US imaging for these procedures. We have developed a supervised 3D US needle applicator segmentation algorithm using a single user input to augment the addition of 3D US to the current focal liver tumor ablation workflow with the goals of identifying and improving needle applicator localization efficiency. The algorithm is initialized by creating a spherical search space of line segments around a manually chosen seed point that is selected by a user on the needle applicator visualized in a 3D US image. The most probable trajectory is chosen by maximizing the count and intensity of threshold voxels along a line segment and is filtered using the Otsu method to determine the tip location. Homogeneous tissue mimicking phantom images containing needle applicators were used to optimize the parameters of the algorithm prior to a four-user investigation on retrospective 3D US images of patients who underwent microwave ablation for liver cancer. Trajectory, axis localization, and tip errors were computed based on comparisons to manual segmentations in 3D US images. Segmentation of needle applicators in ten phantom 3D US images was optimized to median (Q1, Q3) trajectory, axis, and tip errors of 2.1 (1.1, 3.6)°, 1.3 (0.8, 2.1) mm, and 1.3 (0.7, 2.5) mm, respectively, with a mean±SD segmentation computation time of 0.246±0.007s. Use of the segmentation method with a 16 invivo 3D US patient dataset resulted in median (Q1, Q3) trajectory, axis, and tip errors of 4.5 (2.4, 5.2)°, 1.9 (1.7, 2.1) mm, and 5.1 (2.2, 5.9) mm based on all users. Segmentation of needle applicators in 3D US images during minimally invasive liver cancer therapeutic procedures could provide a utility that enables enhanced needle applicator guidance, placement verification, and improved clinical workflow. A semi-automated 3D US needle applicator segmentation algorithm used invivo demonstrated localization of the visualized trajectory and tip with less than 5° and 5.2mm errors, respectively, in less than 0.31s. This offers the ability to assess and adjust needle applicator placements intraoperatively to potentially decrease the observed liver cancer recurrence rates associated with current ablation procedures. Although optimized for deep and oblique angle needle applicator insertions, this proposed workflow has the potential to be altered for a variety of image-guided minimally invasive procedures to improve localization and verification of therapy needle applicators intraoperatively.

An open electromagnetic tracking framework applied to targeted liver tumour ablation.

Electromagnetic tracking is a core platform technology in the navigation and visualisation of image-guided procedures. The technology provides high tracking accuracy in non-line-of-sight environments, allowing instrument navigation in locations where optical tracking is not feasible. EMT can be beneficial in applications such as percutaneous radiofrequency ablation for the treatment of hepatic lesions where the needle tip may be obscured due to difficult liver environments (e.g subcutaneous fat or ablation artefacts). Advances in the field of EMT include novel methods of improving tracking system accuracy, precision and error compensation capabilities, though such system-level improvements cannot be readily incorporated in current therapy applications due to the 'blackbox' nature of commercial tracking solving algorithms. This paper defines a software framework to allow novel EMT designs, and improvements become part of the global design process for image-guided interventions. An exemplary framework is implemented in the Python programming language and demonstrated with the open-source Anser EMT system. The framework is applied in the preclinical setting though targeted liver ablation therapy on an animal model. The developed framework was tested with the Anser EMT electromagnetic tracking platform. Liver tumour targeting was performed using the tracking framework with the CustusX navigation platform using commercially available electromagnetically tracked needles. Ablation of two tumours was performed with a commercially available ablation system. Necropsy of the tumours indicated ablations within 5mm of the tumours. An open-source framework for electromagnetic tracking was presented and effectively demonstrated in the preclinical setting. We believe that this framework provides a structure for future advancement in EMT system in and customised instrument design.

High Frequency Jet Ventilation during stereotactic ablation of liver tumours: an observational study on blood gas analysis as a measure of lung function during general anaesthesia.

Background: Stereotactic ablation of tumours in solid organs is a promising curative procedure in clinical oncology. The technique demands minimal target organ movements to optimise tumour destruction and prevent injury to surrounding tissues. High frequency jet ventilation (HFJV) is a novel option during these procedures, reducing the respiratory-associated movements of the liver. The effects of HFJV via endotracheal catheter on gas exchange during liver tumour ablation is not well studied. Methods: The aim of this explorative study was to assess lung function and the effects on blood gas and lactate during HFJV in patients undergoing stereotactic liver ablation. Blood gases were analysed in 25 patients scheduled for stereotactic liver ablation under general anaesthesia pre-induction, every 15 minutes during HFJV and following extubation in the recovery room. The HFJV was set at fixed settings. Results: None of the patients developed hypoxia or signs of increased lactate production but a great variation in PaO 2/FiO 2 ratio was found; from 13.1 to 71.3. An increase in mean PaCO 2 was observed, from a baseline of 5.0 to a peak of 7.1 at 30 minutes (p <0.001) and a decrease was found in median pH, from a baseline of 7.44 to 7.31 at 15 minutes (p=0.03). We could not see any clear association between a decrease in PaO 2/FiO 2 ratio and PaCO 2 elevation. Conclusions: HFJV during general anaesthesia in patients undergoing stereotactic liver ablation is feasible and it did not cause hypoxemia or signs of increased lactate production. A reversible mild to moderate impairment of gas exchange was found during HFJV.

Periprocedural Management of Patients Undergoing Liver Resection or Embolotherapy for Neuroendocrine Tumor Metastases.

The objective of this study was to describe the periprocedural management of patients with well-differentiated neuroendocrine tumors with hepatic metastases who underwent liver-directed procedures. We performed a retrospective review of patients with metastatic neuroendocrine tumors who underwent liver resection, ablation, or embolotherapy at a single center from 2012 to 2016. The primary outcome was occurrence of documented carcinoid crisis (CC) or hemodynamic instability (HDI), defined as 10 minutes or more of systolic blood pressure less than 80 or greater than 180 mm Hg, or pulse greater than 120 beats per minute. We identified 75 patients who underwent liver resection/ablation (n = 38) or embolotherapy (n = 37). Twenty-four patients (32%) experienced CC or HDI (CC/HDI); CC occurred in 3 patients. No clinicopathologic or procedural factors, including procedure type, octreotide or long-acting somatostatin analog use, and history of carcinoid syndrome, were associated with CC/HDI. Grades 2 to 4 complications were reported in 42% of patients who experienced CC/HDI versus in 16% of patients who did not experience CC/HDI (P < 0.05). A significant portion of patients developed CC/HDI, and these patients were more likely to develop severe postprocedural complications. Periprocedural octreotide use was not associated with lower CC/HDI occurrence, but continued use is advised given its safety profile until additional studies definitively demonstrate lack of benefit.

03:09 PM Abstract No. 180 Liver radiofrequency ablation affects the infiltrated cellular dynamics in the periablational rim and induces aggressiveness in the distant subcutaneous R3230 breast adenocarcinoma tumor

To assess the effect of normal non-tumor liver thermal ablation on periablation rim and distant R3230 breast adenocarcinoma tumor in F344 rats while using atorvastatin as an adjuvant tumor inhibitor. To this end, we used F344 rat (150g, n=65), R3230 breast adenocarcinoma tumor, sham (needle placement without energy for 5 minutes) or RFA (70°C for 5 minutes) with or without atorvastatin IP administration (1.15mg per rat) were used for this study. The rats were grouped into; sham, sham + 24 h post-ablation treatment, sham + daily (0, 24 and 48 h) post-ablation treatment, RFA only, RFA+24 h post-ablation treatment and RFA + daily (0, 24 and 48 h) post-ablation treatment. Tumors were measured daily post-R3230 transplantation until liver harvest at day 3 and 7 post-ablation for IHC and Elisa. We assessed the levels myofibroblast and macrophage infiltration (SMA and CD68 respectively), Ki-67 proliferative indexes, CD34 microvascular density and hepatic growth factor (HGF) in the harvested liver samples. From day 3 to day 7 post-ablation, RFA group significantly increased the distant tumor size when compared to the rest of the treatment groups. RFA + daily (0, 24 and 48 h) atorvastatin treatment group had the least distant tumor growth effect relative to the ablated groups. While there was no significant difference in the amount of SMA expressed in all the sham groups with or without atorvastatin, more than 2-fold increase in the levels of SMA, KI-67, CD38 and CD68 were observed in the periablational rim of the RFA group unlike RFA + 24 h atorvastatin treatment and RFA + daily (0, 24 and 48 h) atorvastatin treatment groups. Also, HGF was least expressed in RFA + daily (0, 24 and 48 h) atorvastatin treatment but not RFA group. RFA + 24 h atorvastatin treatment group showed a moderate level of HGF while there was generally no significant difference among the sham groups (with or without atorvastatin). Our results suggest that the ablation of normal non-tumor bearing liver affects distant subcutaneous R3230 breast tumor growth and alters the infiltrated cellular dynamics of the periablational rim when treated with or without atorvastatin after ablation.

Abstract No. 499 Novel needle guidance technology in the angiography room: from CBCT to stereotaxic reconstruction

To evaluate a new needle guidance tool’s accuracy and potential in patient radiation exposure reduction. An IRB-approved retrospective study of all percutaneous procedures performed using Stereo3D Needle ASSIST (Discovery IGS740 angiography suite, GE Healthcare, Chicago, IL) was conducted. For each case, an initial CBCT was performed and possibly fused to preoperative CT/MR/PET to plan the needle(s) trajectory, and needle(s) were inserted using either trajectory bulls eye and progress overlay fluoroscopic views or using Ultrasound automatic fusion (INTERACT Active Tracker, GE Healthcare). Needle(s) position in the anatomy under treatment was then verified prior to treatment using CBCT or/and Stereo3D technology, which virtually reconstructs needle(s) position in the initial planning CBCT using three fluoroscopic views instead of a full CBCT. The number of needle(s) verification(s) and repositioning(s) was recorded. When both Stereo3D and CBCT were used, Stereo3D reconstruction accuracy was measured for each needle in mm, both in depth and in bulls eye orientation. Results are expressed as median (±SD). Mean patient radiation exposure reduction when using Stereo3D instead of iterative verification CBCTs was also assessed. From January to December 2017, 34 needles were placed in complex IR cases using this new needle guidance technology: 9 liver or kidney ablations, 2 sacroplasties and 1 pleural based lesion biopsy. Needle 3D position was verified 37 times, with Stereo3D used 22 times and full CBCT used 15 times, and re-adjusted 16 times. 10 needle positions were verified with both Stereo3D and CBCT. Stereo3D reconstruction inaccuracy was 2.8mm (±6.3) in depth and 4.4mm (±3.4) off the center of the needle tract. For bone lesions the error was 2mm. Using Stereo3D reduced the procedure air kerma (Gy) and DAP (Gy.cm2) by 27% and 35% on average. Using needle guidance tools enables to significantly reduce the radiation dose exposure to patients during complex interventional radiology procedures while ensuring accurate planning, guidance and position assessment.

3550 Understanding Racial Disparities in Hepatocellular Carcinoma Treatments and Outcomes

OBJECTIVES/SPECIFIC AIMS: Black patients with hepatocellular carcinoma (HCC) receive fewer curative therapies and have higher mortality than other groups. Reducing this disparity will require an in-depth understanding of patient comorbidities, tumor characteristics, and social determinants of health. Our objectives are to a) perform a multi-center retrospective cohort study of black and white patients diagnosed with HCC in the Indianapolis area. b) prospectively enroll black and white patients with HCC to collect clinical characteristics as well as data on the social determinants of health. METHODS/STUDY POPULATION: A retrospective chart review of patients with a diagnosis of HCC from 2010-2017 from five area Indianapolis hospitals will be performed. Demographics, comorbidities, liver disease severity, and tumor characteristics will be collected using the Indiana Network for Patient Care database and compared between black and white patients. Concomitantly, a prospective cohort of black and white patients will be enrolled and surveyed to collect data on socioeconomic status and income adequacy, literacy, functional status, substance abuse history, social support, activation, and adherence. The primary outcomes are the receipt of curative therapies for HCC including liver transplantation, resection or ablation. The secondary outcome is mortality. Multivariable logistic regression models will be used to explore disparities seen in the primary and secondary outcomes. RESULTS/ANTICIPATED RESULTS: These preliminary results include Indiana University Hospital (IUH) findings; a multicenter analysis is underway. The IUH cohort included 1,032 (86%) white and 164 (14%) black patients. Black and white patients had similar Model for End-Stage Liver Disease and Child-Pugh scores. There was a trend toward larger tumor size (5.3 cm vs. 4.7 cm; P = 0.05) in black patients; however, Barcelona Clinic Liver Cancer staging and Milan criteria were similar. Black patients were less likely to undergo liver transplantation than white patients—a disparity that was not attenuated (odds ratio [OR], 0.43; 95% confidence interval [CI]: 0.21-0.90) on multivariable analysis. Substance abuse was more frequently cited as the reason black patients within Milan criteria failed to undergo transplantation than white patients. Survival was similar between the two groups. DISCUSSION/SIGNIFICANCE OF IMPACT: Racial differences in patient and tumor characteristics were small in our single center analysis and did not explain the disparity in liver transplantation. This analysis however only reflects 25% of patients diagnosed with HCC in the Indianapolis metropolitan, highlighting the need for a multicenter study. Higher rates of substance abuse in black patients within Milan criteria who failed to undergo transplantation suggest social factors contribute to this disparity and highlight the need for a prospective study that can explore these and other social factors.

Tampa associating microwave liver ablation with portal vein ligation for staged hepatectomy

Tampa associating microwave liver ablation with portal vein ligation for staged hepatectomy

A Dual-Mode Coaxial Slot Applicator for Microwave Ablation Treatment

Recent developments of microwave ablation systems pursue a treatment monitoring technique in order to provide a curative therapy option for cancer patients. In this paper, such an approach is realized by a dual-mode microwave applicator that enables the permittivity extraction of the tissue surrounding the applicator during the intervention. The additional sensing mode facilitates the positioning of the applicator by detecting dielectric contrasts to indicate the presence of tumors as well as providing tissue state information during the thermal therapy. This feature is based on a one-port calibration scheme which is applied before each intervention. Measurements of various sodium chloride solutions reveal a measurement error below 4%. Furthermore, ex-vivo liver ablation experiments with the input powers of 10 and 20 W are performed to evaluate the treatment monitoring feature and ablation efficacy. A significant permittivity drop down to 82% of the initial permittivity value can be observed after 2 min of ablation. The achieved ablation zones show a preferably spherical shape and clinically relevant volumes with a maximum size of 7.1 cm3.

Contrast-enhanced ultrasound to ultrasound fusion during microwave ablation: feasibility study in a perfused porcine liver model.

To obtain a complete response with thermal ablation, the margin and entire tumor volume must be treated. Real-time ultrasound visualization is limited during ablation due to gas production. This study assesses the feasibility of fusing volumetric contrast-enhanced ultrasound (CEUS), obtained immediately prior to microwave ablation, with real-time CEUS during and following ablation in a machine-perfused porcine liver. Ten, 3-4cm microwave ablations were performed in five explanted perfused livers. Prior to ablation, microbubbles were injected into the vasculature while an ultrasound sweep across the liver captured a volumetric image during maximum enhancement. This volumetric image was then fused to overlay the real-time ultrasound imaging. Since the perfused livers did not have tumors, a spherical marker circumscribing a target volume was placed on the images. Approximatively, 75% of the total intended circumscribed spherical volume was ablated. Following ablation, a second bolus injection of ultrasound contrast was administered demonstrating continued enhancement of the intentionally non-ablated 25%. A second volumetric image of the post-ablation CEUS was then fused to overlay the real-time ultrasound images for guidance during ablation of the remaining enhancing volume. Technical success was achieved in 100% of the cases. The pre- and then the post-ablation CEUS volume was fused with real-time imaging during antenna placement for initial and subsequent ablation. CEUS-CEUS fusion during thermal ablation is feasible and greatly improves the workflow. The approach may augment the use of dynamic CEUS for guidance, improving antenna placement, and aiding in the identification and ablation of initial and residual enhancing tissue.