Major Hepatic Vessels Research Articles

Stereotactic body radiation therapy in patients with centrally located hepatocellular carcinoma: A retrospective, single-arm, multi-center study

Centrally located hepatocellular carcinoma (HCC) is difficult to be radically resected due to its special location close to major hepatic vessels. Thus, we aimed to assess whether stereotactic body radiation therapy (SBRT) can be an effective and safe approach for centrally located HCC. This retrospective study included 172 patients with centrally located HCC who were treated with SBRT. Overall survival (OS) was analyzed as the primary endpoint. Rates of progression-free survival (PFS), local control, intrahepatic relapse, extrahepatic metastasis and toxicities were analyzed as secondary endpoints. The OS rates of 1-, 3-, and 5-year were 97.7%, 86.7%, and 76.3%, respectively. The PFS/local control rates of 1-, 3-, and 5-year were 94.1%/98.2%, 76.8%/94.9%, and 59.3%/92.3%, respectively. The cumulative incidence of intrahepatic relapse/extrahepatic metastases of 1-, 3-, and 5-year were 3.7%/2.9%, 25.0%/7.4%, and 33.3%/9.8%, respectively. Both univariate and multivariate analyses revealed that patients received BED10 at 100 Gy or more had better OS. Radiation-related adverse events were mild to moderate according to Common Terminology Criteria for Adverse Events, and no toxicities over grade 3 were observed. Patients with centrally located HCC in our cohort who received SBRT had similar OS and PFS rates compared to those reported in literatures who received surgery with neoadjuvant or adjuvant intensity-modulated radiation therapy. These results indicate that SBRT is an effective and well-tolerated method for patients with centrally located HCC, suggesting that it may serve as a reasonable alternative treatment for these kind of patients.

Numerical mesoscale tissue model of electrochemotherapy in liver based on histological findings

Electrochemotherapy (ECT) and irreversible electroporation (IRE) are being investigated for treatment of hepatic tumours. The liver is a highly heterogeneous organ, permeated with a network of macro- and microvasculature, biliary tracts and connective tissue. The success of ECT and IRE depends on sufficient electric field established in whole target tissue; therefore, tissue heterogeneity may affect the treatment outcome. In this study, we investigate electroporation in the liver using a numerical mesoscale tissue model. We numerically reconstructed four ECT experiments in healthy porcine liver and computed the electric field distribution using our treatment planning framework. We compared the computed results with histopathological changes identified on microscopic images after treatment. The mean electric field threshold that best fitted the zone of coagulation necrosis was 1225 V/cm, while the mean threshold that best fitted the zone of partially damaged liver parenchyma attributed to IRE was 805 V/cm. We evaluated how the liver macro- and microstructures affect the electric field distribution. Our results show that the liver microstructure does not significantly affect the electric field distribution on the level needed for treatment planning. However, major hepatic vessels and portal spaces significantly affect the electric field distribution, and should be considered when planning treatments.

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Abdomen and/or Retroperitoneum.

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Abdomen and/or Retroperitoneum.

Triple liver hanging maneuver for hepatic central bisectionectomy with caudate lobectomy for resection of huge hepatocellular carcinoma (with video).

Resection of huge hepatocellular carcinomas occupying the central portion of the liver is challenging. Exposure of an adequate liver transection plane using an anterior approach is likely to be difficult because of compression by the tumor. We herein propose a "triple liver hanging maneuver" technique for central bisectionectomy with caudate lobectomy for huge hepatocellular carcinomas stretching the hilar plate and the right and left hepatic veins. In this technique, the first tape is introduced for the transection plane along the right side of the umbilical portion to the anterior surface of the inferior vena cava. The second tape is introduced to lift the paracaval caudate Glissonean pedicles from the hilar plate. The third tape is introduced for the transection plane along the right hepatic vein to the anterior surface of the inferior vena cava. The triple liver hanging maneuver could be effective for huge tumors compressing major hepatic vessels.

Perivascular vital cells in the ablation center after multibipolar radiofrequency ablation in an in vivo porcine model

Multibipolar radiofrequency ablation (RFA) is an advanced ablation technique for early stage hepatocellular carcinoma and liver metastases. Vessel cooling in multibipolar RFA has not been systematically investigated. The objective of this study was to evaluate the presence of perivascular vital cells within the ablation zone after multibipolar RFA. Multibipolar RFA were performed in domestic pigs in vivo. Three internally cooled bipolar RFA applicators were used simultaneously. Three experimental settings were planned: (1) inter-applicator-distance: 15 mm; (2) inter-applicator-distance: 20 mm; (3) inter-applicator-distance: 20 mm with hepatic inflow occlusion (Pringle maneuver). A vitality staining was used to analyze liver cell vitality around all vessels in the ablation center with a diameter > 0.5 mm histologically. 771 vessels were identified. No vital tissue was seen around 423 out of 429 vessels (98.6%) situated within the central white zone. Vital cells could be observed around major hepatic vessels situated adjacent to the ablation center. Vessel diameter (> 3.0 mm; p < 0.05) and low vessel-to-ablation-center distance (< 0.2 mm; p < 0.05) were identified as risk factors for incomplete ablation adjacent to hepatic vessels. The vast majority of vessels, which were localized in the clinically relevant white zone, showed no vital perivascular cells, regardless of vessel diameter and vessel type. However, there was a risk of incomplete ablation around major hepatic vessels situated directly within the ablation center. A Pringle maneuver could avoid incomplete ablations.

Technique for comprehensive fetal hepatic blood flow assessment in sheep using 4D flow MRI.

The comprehensive visualization and quantification of in vivo fetal hepatic haemodynamics, particularly the shunting of ductus venosus blood, has been elusive and is not yet fully understood. We introduce the combination of chronically instrumented fetal sheep and 4D flow MRI of the whole fetal liver, which allows retrospective blood flow measurement in all visible vessels as well as qualitative assessment. The applicability and usefulness of this technique is exhibited in normally grown fetal Merino sheep in mid- and late-gestation with detailed dynamic distribution of hepatic blood flow presented. The feasibility of this approach in clinical pathology is demonstrated in two growth-restricted fetuses at mid-gestation. Further exemplification of blood flow quantification is performed over major hepatic vessels. Although the fetal vasculature has been demarcated and well understood for several decades, the corresponding haemodynamics permitting oxygen- and nutrient-rich blood delivery to the fetal organs has been comparatively difficult to study. We married two well-established methods: 4D flow MRI, a volumetric and dynamic blood-flow measurement technique, and chronically instrumented sheep to broadly assess fetal hepatic circulation. We performed this technique in mid- and late-gestation fetal Merino sheep under normoxemic conditions and major hepatic vasculature was segmented to quantify blood flow and related parameters. Dynamic blood flow was visualized, exhibiting an acceleration of umbilical vein blood through the ductus venosus as well as spiralling into the inferior vena cava where its stream remained separate from that of the hepatic veins and lower body. Ductus venosus changes from mid- to late-gestation included larger diameter (mid: 5.8±0.9 vs. late: 7.1±1.1mm; P=0.003) and cross-sectional area (mid: 27.1±8.6 vs. late: 40.4±11.8mm2 ; P=0.003), and lower velocity averaged over the cardiac cycle (mid: 15.7±5.4 vs. late: 9.8±7.0cms-1 ; P=0.020). This resulted in higher magnitude blood flow (indexed to umbilical vein input) at mid-gestation in the ductus venosus (mid: 0.73±0.21; late: 0.46±0.21; P=0.008). The visualization and quantification results support the further use of this technique to better understand regional blood flow changes during normal or abnormal fetal growth, as well as to observe acute haemodynamic responses to physiological challenges or drug interventions.

Outcome and management strategy of traumatic liver injury in a tertiary hospital in Bangladesh

Background: Liver remains the second most common injured organ in both blunt and penetrating trauma of the abdomen. Management of blunt or penetrating injury to the liver remains a significant challenge to trauma surgeons. Unstable patients require immediate laparotomy. Selective patients can be managed without surgery and with careful monitoring. Mortality is mainly due to damage to major hepatic blood vessels, massive parenchymal and biliary injury. Associated non-hepatic injuries contribute greatly to the overall mortality. With improved understanding of the major causes of mortality from hepatic injury, adequate resuscitation, well planned surgical intervention and better intensive care facilities have decreased mortality and morbidity&#x0D; Objectives: Performed to assess incidence, mechanisms, management and outcome of traumatic liver injury. Methods: This prospective study was performed in Dhaka Medical College Hospital between January 2013 to December 2014. Sixty patients with hepatic injury were included in the study. Data collected in data collection sheet regarding demographic data, severity of liver injury, hemodynamic status on admission, investigations reports, concomitant injuries, management scheme, and outcome of patients which were then analyzed.&#x0D; Results: There were 39 male and 21 female patients with a mean age of 31.3 (SD=15.4) years. Road traffic accident was the most common injury mechanism (71%). 20 patients (33%) were in shock at the time of admission. 48 patients (80%) with liver injury had associated injuries of other organs. Majority of the patients (41%) were found with grade Ill injury. 50 patients (83%) needed surgical interventions. Most common (16%) complication was wound infection. 3 patients (5%) died in this series. 5 patients (8%) developed liver abscess on subsequent follow up. Conclusion: Most of the trauma victims are young and in the active state of life. Prompt resuscitative measures, assessment of extend of hepatic injury and associated injuries, well justified surgical intervention along with critical care support can contribute greatly to the survival of victims of hepatic injury.&#x0D; Journal of Surgical Sciences (2018) Vol. 22 (1): 36-42

Use of a cavitron ultrasonic surgical aspirator for parenchyma-sparing and complex liver resections in dogs.

To report the clinical use of a cavitron ultrasonic surgical aspirator (CUSA) for the resection of hepatic lesions in dogs. Clinical prospective study. Eleven client-owned dogs. Dogs requiring a hepatic nodulectomy, segmentectomy, and/or a lobectomy (including complex lobectomies) were enrolled. The number and location of procedures, blood loss, duration of surgery, and short-term complications were recorded. Dogs underwent a mean of 2.3 ± 1.1 procedures. All masses were amenable to surgical excision regardless of their location and their relationship with major hepatic vessels. Dogs lost a median of 77 mL of blood (9.9-161), which corresponded to 4.3% of blood volume (0.8%-23.2%). The dog with the highest blood loss survived without requiring transfusion. The median duration of all CUSA procedures was 33.5 minutes (15-82). Short-term outcomes were assessed for the first 15 days, during which two complications were diagnosed. Cholangiohepatitis was diagnosed in one dog and resolved after medical management, and another dog developed necrotic pancreatitis and died. Liver parenchyma-sparing nodulectomies and segmentectomies and liver lobectomies including complex lobectomies were achieved with a CUSA in all dogs. Use of a CUSA can be considered as an alternative for the removal of hepatic lesions in dogs.

Electrochemotherapy as treatment option for hepatocellular carcinoma, a prospective pilot study

Background and objectivesElectrochemotherapy provides non-thermal ablation of cutaneous as well as deep seated tumors. Based on positive results of the treatment of colorectal liver metastases, we conducted a prospective pilot study on hepatocellular carcinomas with the aim of testing the feasibility, safety and effectiveness of electrochemotherapy. Patients and methodsElectrochemotherapy with bleomycin was performed on 17 hepatocellular carcinomas in 10 patients using a previously established protocol. The procedure was performed during open surgery and the patients were followed for median 20.5 months. ResultsElectrochemotherapy was feasible for all 17 lesions, and no treatment-related adverse events or major post-operative complications were observed. The median size of the treated lesions was 24 mm (range 8–41 mm), located either centrally, i.e., near the major hepatic vessels, or peripherally. The complete response rate at 3–6 months was 80% per patient and 88% per treated lesion. ConclusionsElectrochemotherapy of hepatocellular carcinoma proved to be a feasible and safe treatment in all 10 patients included in this study. To evaluate the effectiveness of this method, longer observation period is needed; however the results at medium observation time of 20.5 months after treatment are encouraging, in 15 out of 17 lesions complete response was obtained. Electrochemotherapy is predominantly applicable in patients with impaired liver function due to liver cirrhosis and/or with lesions where a high-risk operation is needed to achieve curative intent, given the intra/perioperative risk for high morbidity and mortality.

Risk factors of massive blood loss during resection of giant liver hemangioma

Objective To evaluate the risk factors of massive blood loss in resection of giant liver hemangioma. Method The clinical data of 141 patients who underwent giant liver hemangioma resection were retrospectively studied. These data included general physical condition, laboratory tests, radiologic findings, and various surgical parameters. The patients were divided into the massive blood loss group (>1 000 ml, n=27) and the minor blood loss group (≤1 000 ml, n=114). Logistic regression was performed to determine the risk factors of intraoperative massive blood loss. Results The average diameter of the liver hemangioma was significantly greater in the massive blood loss group than that in the minor blood loss group [(21.7±8.5) cm vs. (14.1±5.3) cm, P<0.05]. The incidences of preoperative leukopenia, anemia, thrombocytopenia and prolonged prothrombin time were higher in the massive blood loss group than that in the minor blood loss group (48.1% vs. 16.7%, 37.0% vs. 11.4%, 25.9% vs. 3.5%, 22.2% vs. 3.5%, respectively, all P<0.05). Hepatic hemangioma with compressed hepatic veins, inferior vena cava and porta hepatis were more frequently found in the massive blood loss group than in the minor blood group (55.6% vs. 14.9%, 44.4% vs. 14.0%, 55.6% vs. 12.3%, respectively, all P<0.05). Logistic regression analysis demonstrated a diameter of hemangioma greater than 15 cm was a risk factor of intraoperative massive blood loss during surgical resection. Conclusions Giant hepatic hemangioma may cause disorders in the hematological and coagulation systems. Compression of major hepatic vessels raised technical difficulty and risks in surgery. Hemangioma with a diameter greater than 15 cm was recognized as a high-risk factor of intraoperative massive blood loss. Key words: Liver tumor; Giant hemangioma; Surgical procedure; Massive blood loss

Does acid-base equilibrium correlate with remnant liver volume during stepwise liver resection?

Small for size and flow syndrome (SFSF) is one of the most challenging complications following extended hepatectomy (EH). After EH, hepatic artery flow decreases and portal vein flow increases per 100 g of remnant liver volume (RLV). This causes hypoxia followed by metabolic acidosis. A correlation between acidosis and posthepatectomy liver failure has been postulated but not studied systematically in a large animal model or clinical setting. In our study, we performed stepwise liver resections on nine pigs to defined SFSF limits as follows: step 1: segment II/III resection, step 2: segment IV resection, step 3: segment V/VIII resection (RLV: 75, 50, and 25%, respectively). Blood gas values were measured before and after each step using four catheters inserted into the carotid artery, internal jugular vein, hepatic artery, and portal vein. The pH, [Formula: see text], and base excess (BE) decreased, but [Formula: see text] values increased after 75% resection in the portal and jugular veins. EH correlated with reduced BE in the hepatic artery. Pco2 values increased after 75% resection in the jugular vein. In contrast, arterial Po2 increased after every resection, whereas the venous Po2 decreased slightly. There were differences in venous [Formula: see text], BE in the hepatic artery, and Pco2 in the jugular vein after 75% liver resection. Because 75% resection is the limit for SFSF, these noninvasive blood evaluations may be used to predict SFSF. Further studies with long-term follow-up are required to validate this correlation.NEW & NOTEWORTHY This is the first study to evaluate acid-base parameters in major central and hepatic vessels during stepwise liver resection. The pH, [Formula: see text], and base excess (BE) decreased, but [Formula: see text] values increased after 75% resection in the portal and jugular veins. Extended hepatectomy correlated with reduced BE in the hepatic artery. Because 75% resection is the limit for small for size and flow syndrome (SFSF), postresection blood gas evaluations may be used to predict SFSF.

Application value of laparoscopic radiofrequency ablation for specific-location hepatocellular carcinoma

Objective: To investigate the therapeutic efficacy and safety of laparoscopic radiofrequency ablation (LRFA) for specific-location hepatocellular carcinoma. Methods: To retrospectively analyze 496 patients with specific-location hepatocellular carcinoma treated with LRFA from January 2010 to January 2015 in our hospital. There was a total of 652 hepatic lesions with a mean diameter of (2.8±1.3) cm including 397 cases with single lesion and 99 cases with multiple lesions. The hepatic lesions were adjacent to major hepatic vessels, hepatic hilar region, diaphragmatic dome, gallbladder, or gastrointestinal tract and on the surface of the liver, respectively. Results: The 496 patients with 652 hepatic lesions were treated with LRFA successfully.The mean operation time was (48.2±9.6) minutes and the mean LRFA time per lesion was (30.3±8.6) minutes. No severe complications such as bleeding, bile leakage, gastrointestinal tract damage, diaphragmatic injury and liver function failure occurred after operation. The complete necrosis rate of the specific-location hepatocellular carcinomas was 78.4% (389/496) in one month after RFA, partially necrosis rate was 21.6% (107/496) and overall necrosis rate was 100%. In addition, the 1- and 3-year overall survivals (OS) were 95.6% and 88.5%, and progression free survivals (DFS) were 87.9% and 80.8%, respectively. Conclusions: LRFA is a safe, effective, economic and minimally-invasive therapeutic approach for patients with specific-location hepatocelluar carcinoma and has good clinical application value.

Intensity-modulated radiotherapy following null-margin resection is associated with improved survival in the treatment of intrahepatic cholangiocarcinoma.

The current study is the first to examine the effectiveness and toxicity of postoperative intensity-modulated radiotherapy (IMRT) in the treatment of intrahepatic cholangiocarcinoma (ICC) abutting the vasculature. Specifically, we aim to assess the role of IMRT in patients with ICC undergoing null-margin (no real resection margin) resection. Thirty-eight patients with ICC adherent to major blood vessels were included in this retrospective study. Null-margin resection was performed on all patients; 14 patients were further treated with IMRT. The median radiation dose delivered was 56.8 Gy (range, 50-60 Gy). The primary endpoints were overall survival (OS) and disease-free survival (DFS). At a median follow-up of 24.6 months, the median OS and DFS of all patients (n=38) were 17.7 months (95% CI, 13.2-22.2) and 9.9 months (95% CI, 2.8-17.0), respectively. Median OS was 21.8 months (95% CI, 15.5-28.1) among the 14 patients in the postoperative IMRT group and 15.0 months (95% CI, 9.2-20.9) among the 24 patients in the surgery-only group (P=0.049). Median DFS was 12.5 months (95% CI, 6.8-18.2) in the postoperative IMRT group and 5.5 months (95% CI, 0.7-12.3) in the surgery-only group (P=0.081). IMRT was well-tolerated. Acute toxicity included one case of Grade 3 leukopenia; late toxicity included one case of asymptomatic duodenal ulcer discovered through endoscopy. The study results suggest that postoperative IMRT is a safe and effective treatment option following null-margin resections of ICC. Larger prospective and randomized trials are necessary to establish postoperative IMRT as a standard practice for the treatment of ICC adherent to major hepatic vessels.

Segmentation of hepatic vessels from MRI images for planning of electroporation-based treatments in the liver.

Introduction.Electroporation-based treatments rely on increasing the permeability of the cell membrane by high voltage electric pulses delivered to tissue via electrodes. To ensure that the whole tumor is covered by the sufficiently high electric field, accurate numerical models are built based on individual patient geometry. For the purpose of reconstruction of hepatic vessels from MRI images we searched for an optimal segmentation method that would meet the following initial criteria: identify major hepatic vessels, be robust and work with minimal user input.Materials and methods.We tested the approaches based on vessel enhancement filtering, thresholding, and their combination in local thresholding. The methods were evaluated on a phantom and clinical data.ResultsResults show that thresholding based on variance minimization provides less error than the one based on entropy maximization. Best results were achieved by performing local thresholding of the original de-biased image in the regions of interest which were determined through previous vessel-enhancement filtering. In evaluation on clinical cases the proposed method scored in average sensitivity of 93.68%, average symmetric surface distance of 0.89 mm and Hausdorff distance of 4.04 mm.ConclusionsThe proposed method to segment hepatic vessels from MRI images based on local thresholding meets all the initial criteria set at the beginning of the study and necessary to be used in treatment planning of electroporation-based treatments: it identifies the major vessels, provides results with consistent accuracy and works completely automatically. Whether the achieved accuracy is acceptable or not for treatment planning models remains to be verified through numerical modeling of effects of the segmentation error on the distribution of the electric field.

Intraoperative electrochemotherapy of colorectal liver metastases

Electrochemotherapy is effective in treatment of various cutaneous tumors and could be translated into treatment of deep-seated tumors. With this aim a prospective pilot study was conducted to evaluate feasibility, safety, and efficacy of intraoperative electrochemotherapy in the treatment of colorectal liver metastases. Electrochemotherapy with bleomycin was performed during open surgery, by insertion of long needle electrodes into and around the tumor according to the individualized pretreatment plan. A 29 metastases in 16 patients were treated in 16 electrochemotherapy sessions. No immediate (intraoperative) and/or postoperative serious adverse events related to electrochemotherapy were observed. Radiological evaluation of all the treated metastases showed 85% complete responses and 15% partial responses. In a group of seven patients that underwent a second operation at 6-12 weeks after the first one, during which electrochemotherapy was performed, the histology of resected metastases treated by electrochemotherapy showed less viable tissue (P = 0.001) compared to non-treated ones. Electrochemotherapy of colorectal liver metastases proved to be feasible, safe, and efficient treatment modality, providing its specific place in difficult to treat metastases, located in the vicinity of major hepatic vessels, not amenable to surgery or radiofrequency ablation.

“One-Off” Complete Radiofrequency Ablation for Hepatocellular Carcinoma in a “High-Risk Location” Adjacent to the Major Bile Duct and Hepatic Blood Vessel

Radiofrequency ablation (RFA) is an effective, minimally invasive treatment option for unresectable hepatocellular carcinomas (HCCs) located in high-risk areas or for patients with poor hepatic functional reserve. However, for tumors adjacent to major bile ducts and hepatic blood vessels, complete ablation is difficult to achieve for fear of causing a postoperative bile leak, bilioma or bile duct stenosis. Therefore, RFA is often combined with multiple alcohol injections to eliminate residual tumor tissues in adjacent bile duct or blood vessels; however, the injections directly affect the efficacy and prognosis of RFA. This study reports three successful "one-off" cases of complete ablation of HCCs adjacent to major bile ducts and blood vessels in neighboring hepatic segments or hepatic lobes, highlighting both the efficacy and safety of RFA for HCC tumors in these high-risk locations.

Multipolar radiofrequency ablation for colorectal liver metastases close to major hepatic vessels

BackgroundResection of colorectal liver metastases (CRLM) is often hindered by their location close to the major hepatic vessels. So far, radiofrequency ablation for perivascular tumours was thought to be ineffective and unsafe due to either the heat sink effect or vascular thrombosis. The aim of this study was to examine whether RFA using multipolar probes could be a safe and effective option for CRLM adjacent to major hepatic vessels. MethodsPatients were treated with multipolar RFA during an open procedure using 3 simultaneously placed electrodes. In 52 consecutive patients with CRLM, 144 tumours were ablated with RFA. In 16 out of 52 (31%) patients, metastases were abutting major hepatic vessels. We examined whether perivascular location was a risk factor for local tumour progression. The relation between perivascular location and time to local tumour progression and recurrence free survival was assessed using cox-regression analysis. ResultsAll patients were followed for at least 3 years after RFA unless they deceased before this time. Local tumour progression following RFA occurred in 17 out of 144 tumours (12%), of which 4 out of 21 were perivascular tumours. Tumour size was the only risk factor for local tumour progression in this study. Proximity to large vessels was neither a risk factor for local local tumour progression, nor for time to local tumour progression or recurrence free survival. DiscussionThis study indicates that patients with CRLM abutting any of the large hepatic vessels can be safe and effectively treated with RFA when using a multipolar system.

Effects of tissue mechanical properties on susceptibility to histotripsy-induced tissue damage

Histotripsy is a non-invasive tissue ablation method capable of fractionating tissue by controlling acoustic cavitation. To determine the fractionation susceptibility of various tissues, we investigated histotripsy-induced damage on tissue phantoms and ex vivo tissues with different mechanical strengths. A histotripsy bubble cloud was formed at tissue phantom surfaces using 5-cycle long ultrasound pulses with peak negative pressure of 18 MPa and PRFs of 10, 100, and 1000 Hz. Results showed significantly smaller lesions were generated in tissue phantoms of higher mechanical strength. Histotripsy was also applied to 43 different ex vivo porcine tissues with a wide range of mechanical properties. Gross morphology demonstrated stronger tissues with higher ultimate stress, higher density, and lower water content were more resistant to histotripsy damage in comparison to weaker tissues. Based on these results, a self-limiting vessel-sparing treatment strategy was developed in an attempt to preserve major vessels while fractionating the surrounding target tissue. This strategy was tested in porcine liver in vivo. After treatment, major hepatic blood vessels and bile ducts remained intact within a completely fractionated liver volume. These results identify varying susceptibilities of tissues to histotripsy therapy and provide a rational basis to optimize histotripsy parameters for treatment of specific tissues.

Tissue Ablation Accelerated by Peripheral Scanning Mode with High-Intensity Focused Ultrasound: A Study on Isolated Porcine Liver Perfusion

The aims of this study were to investigate the feasibility of accelerated tissue ablation using a peripheral scanning mode with high-intensity focused ultrasound (HIFU) and to explore the effect of flow rate on total energy consumption of the target tissues. Using a model of isolated porcine liver perfusion via the portal vein and hepatic artery, we conducted a scanning protocol along the periphery of the target tissues using linear-scanned HIFU to carefully adjust the varying focal depth, generator power, scanning velocity and line-by-line interval over the entire ablation range. Porcine livers were divided into four ablation groups: group 1, n = 12, with dual-vessel perfusion; group 2, n = 11, with portal vein perfusion alone; group 3, n = 10, with hepatic artery perfusion alone; and group 4, n = 11, control group with no-flow perfusion. The samples were cut open consecutively at a thickness of 3 mm, and the actual ablation ranges were calculated along the periphery of the target tissues after triphenyl tetrazolium chloride staining. Total energy consumption was calculated as the sum of the energy requirements at various focal depths in each group. On the basis of the pre-supposed scanning protocol, the peripheral region of the target tissue formed a complete coagulation necrosis barrier in each group with varying dose combinations, and the volume of the peripheral necrotic area did not differ significantly among the four groups (p > 0.05). Furthermore, total energy consumption in each group significantly decreased with the corresponding decrease in flow rate (p < 0.01). This study revealed that the complete peripheral necrosis barrier within the target tissues can defined using linear-scanned HIFU in an isolated porcine liver perfusion model. Additionally, the flow rate in the major hepatic vessels may play an important role in the use of the peripheral ablation mode, and this novel mode of ablation may enhance the therapeutic efficacy and tolerability of the treatment of large tumors using HIFU ablation.

Adoption of new selection criteria on living donor liver transplantation for hepatocellular carcinoma and their impact on the outcome.

In cadaveric liver transplantation, the Milan criteria have been accepted as the selection criteria for HCC in considering organ allocation. However, the situation in LDLT is different. This is a retrospective study on 518 recipients who underwent LDLT. The exclusion criteria included HCC with extrahepatic spread and HCC extending to the major hepatic vessels detected during the preoperative evaluation. HCC was the indication in 96 patients (18.5%); 52/96 patients (54.2%) fulfilled Milan criteria and 44/96 patients (45.8%) did not. The 5-year survival rate among patients fulfilling Milan criteria was 40/52 (77.0%) while for those who did not 30/44 (68.0%). Although these results show better survival rates among patients with HCC within the Milan criteria, they are insignificant (p=0.01) and they clearly demonstrate that patients with HCC outside the Milan criteria have nearly the same survival rate as patients with HCC within Milan criteria. Transplantation is the best treatment option for patients with HCC if a careful search reveals no extra-hepatic disease. The application of the Milan criteria for all patients with HCC would have denied many patients who can survive after transplantation. In LDLT programs, where the patient has a special living donor, the Milan criteria are not necessarily relevant.