Does inclusion of bioactive n-3 PUFAs in parenteral nutrition benefit postoperative patients undergoing liver surgery? A systematic review and meta-analysis of randomised control trials.

OBJECTIVES: This meta-analysis aims to evaluate the effect of n-3 polyunsaturated fatty acids (PUFAs) as a part of parenteral nutrition in patients undergoing liver surgery. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, the Cochrane Central Register of Controlled Trials, Springer link, Web of Science, China National Knowledge Infrastructure and VIP Database. ELIGIBILITY CRITERIA: We included randomised controlled trials (RCTs) and evaluated the outcomes of liver function, inflammatory reaction, the influence of certain markers of the immune system, and specific clinical indexes for patients undergoing liver surgery and receiving parenteral nutrition with n-3 PUFAs. DATA EXTRACTION AND SYNTHESIS: The Cochrane Collaboration's tool was used to assess the risk of bias for each study. Findings were summarised in Grades of Recommendation, Assessment, Development and Evaluation evidence profiles and synthesised qualitatively. RESULTS: Eight RCTs, including 748 patients (trial: 374; control: 374), were included in the meta-analysis. Compared with patients in the control group, the patients in the n-3 PUFA group who underwent liver surgery had significantly lower aspartate aminotransferase (mean difference, MD -42.72 (95% CI -71.91 to -13.52); p=0.004), alanine aminotransferase (MD -38.90 (95% CI -65.44 to -12.37); p=0.004), white cell count (MD -0.93 (95% CI -1.60 to -0.26); p=0.007) and IL-6 (MD -11.37 (95% CI -14.62 to -8.13); p<0.00001) levels and a higher albumin level (MD 0.42 (95% CI 0.26 to 0.57); p<0.00001). They also had fewer infection complications (OR 0.44 (95% CI 0.28 to 0.68); p=0.0003) and a shorter duration of hospital stay (MD -2.17 (95% CI -3.04 to -1.3); p<0.00001) than the controls. However, there were no significant differences in terms of total bilirubin, TNF-α, IL-2, IgA, IgG, IgM and CD3, biliary leakage and mortality between the two groups. CONCLUSIONS: We found that n-3 PUFAs can benefit patients undergoing liver surgery by improving liver function and certain clinical indexes and decreasing related inflammation factors. However, there are limited RCTs on the application of n-3 PUFAs for patients undergoing liver surgery. Further evidence of the benefit of n-3 PUFAs in these patients warrants further exploration.

Dietary Linoleic Acid: An Omega-6 Fatty Acid Essential for Liver Regeneration in Buffalo Rats.

Rodents are currently the most common animals used for hepatic surgical resection studies that investigate liver regeneration, chronic liver disease, acute liver failure, hepatic metastasis, hepatic function, and hepatic cancer. Our previous work has shown that dietary consumption of linoleic acid (LA) stimulates the growth of rodent and human tumors in vivo. Here we compared 3 diets - a 5% corn oil diet (control), a diet deficient in essential fatty acids (EFAD), and an EFAD supplemented with LA in amounts equal to those in the control diet (EFAD+LA). We hypothesized that consumption of the LA provided in the EFAD+LA diet would elevate plasma levels of LA and stimulate regeneration in rats after a 70% hepatectomy (HPX), and that regeneration would not occur in the EFAD rats. Each diet group was comprised of 30 male and 30 female Buffalo rats (BUFF/CrCrl). Rats were fed one of the 3 diets and water ad libitum. After 8 wk on the assigned diet, rats were underwent a 70% HPX. On days 4 and 21 after HPX, 30 male and 30 female rats from each diet group were anesthetized for in vivo study and then were euthanized for tissue collection. For the in vivo study, arterial and venous blood samples were collected from the liver. LA-, glucose-, and O2 -uptake, and lactate- and CO2 -output were significantly higher in LA-replete rats as compared with LA-deficient rats. After a 70% HPX, the remaining liver mass in control and EFAD+LA groups had doubled at day 4, reaching 60% of the original total weight, and had regenerated completely at day 21. However, no regeneration occurred in the EFAD group. At day 4 the portions of livers removed from the control and EFAD+LA groups had significantly higher content of LA, protein, cAMP, and DNA as compared with their livers on day 21. [³ H]thymidine incorporation into liver DNA was significantly higher in the 2 LA-replete groups, with male values greater than female values, as compared with LA-deficient group. These data indicate that liver regeneration after HPX is dependent on dietary LA. Understanding the mechanisms of LA-dependent liver regeneration in rats supports our current efforts to enhance successful surgical resection therapies in humans.

Controlled Hyperthermia With High-Intensity Focused Ultrasound and Ultrasound Contrast Agent Microbubbles in Porcine Liver.

OBJECTIVE: The objective of this work was to study microbubble-enhanced temperature elevation with high-intensity focused ultrasound (HIFU) at different acoustic pressures and under image guidance. The microbubbles were administered with either local or vascular injections (that mimic systemic injections) in perfused and non-perfused ex vivo porcine liver under ultrasound image guidance. METHODS: Porcine liver was insonified for 30 s with a single-element HIFU transducer (0.9 MHz, 0.413 ms, 82% duty cycle, focal pressures of 0.6-3.5 MPa). Contrast microbubbles were injected either locally or through the vasculature. A needle thermocouple at the focus measured temperature elevation. Diagnostic ultrasound (Philips iU22, C5-1 probe) guided placement of the thermocouple and delivery of microbubbles and monitored the procedure in real time. RESULTS: At lower acoustic pressures (0.6 and 1.2 MPa) in non-perfused liver, inertial cavitation of the injected microbubbles led to greater temperatures at the focus compared with HIFU-only treatments. At higher pressures (2.4 and 3.5 MPa) native inertial cavitation in the tissue (without injecting microbubbles) resulted in temperature elevations similar to those after injecting microbubbles. The heated area was larger when using microbubbles at all pressures. In the presence of perfusion, only local injections provided a sufficiently high concentration of microbubbles necessary for significant temperature enhancement. CONCLUSION: Local injections of microbubbles provide a higher concentration of microbubbles in a smaller area, avoiding acoustic shadowing, and can lead to higher temperature elevation at lower pressures and increase the size of the heated area at all pressures.

Experiments on physical ablation of long bone using microwave ablation; defining optimal settings using ex- and in-vivo experiments.

BACKGROUND: Improved survival of cancer patients leads to more skeletal metastatic lesions that need local therapies for tumor control and pain relief. Not all tumors are radiosensitive and alternative therapies are direly needed. Microwave ablation (MWA) is a technique for minimally invasive local tumor control by physical ablation. In soft tissue local temperature ablation is more common, but studies on bone tissue are limited. To ensure safe and effective treatment, studies on local tumor ablation in bone are needed. METHOD: Microwave ablation was performed on sheep bone, for both in- and ex-vivo settings. Both a slow-cooking MWA protocol (gradually increasing wattage in the first two minutes of ablation) and a fast-cooking protocol (no warm-up period) were used. Heat distribution through the bone during ablation was determined by measuring temperature at 10- and 15mm from the ablation probe (= needle). Ablation size after procedure was measured using nitro-BT staining. RESULTS: In-vivo ablations led to up to six times larger halos than ex-vivo with the same settings. Within both ex- and in-vivo experiments, no differences in halo size or temperature were found for different wattage levels (65W vs 80W). Compared to a fast cooking protocol, a two-minute slow cooking protocol led to increased temperatures and larger halos. Temperatures at 10- and 15mm distance from the needle no longer increased after six minutes. Halo sizes kept increasing over time without an evident plateau. CONCLUSION: Microwave ablation is technically effective for creating cell death in (sheep) long bone. It is recommended to start ablations with a slow-cooking period, gradually increasing the surrounding tissue temperature in two minutes from 40 to 90°C. Ex-vivo results cannot simply be translated to in-vivo.

Linear endovenous energy density (LEED) should always be quoted with the power used in endovenous thermal ablation - results from an in-vitro porcine liver model study.

BACKGROUND: Linear Endovenous Energy Density (LEED) is the energy used per cm of vein in endovenous thermal ablation (EVTA) but does not include time. This study examines the effect of time during EVTA. METHOD: EVTA was performed in a previously validated porcine liver model. LEEDs of 40, 60, 80 and 100 J/cm, using different powers were repeated 5 times each. Thermal spread, tissue carbonisation and device-tissue sticking during treatment were recorded. RESULT: LEED positively correlated to thermal spread and carbonisation of the tissue. Power was correlated with carbonisation but not thermal spread. Pullback had no correlations with thermal spread or carbonisation. Catheter sticking found occurred in powers >= 15 W or LEED >= 80 J/cm. CONCLUSION: LEED is a good measure of EVTA but does not include time. Power, which does include time, correlates with carbonisation and with device-tissue sticking. The power used must be quoted with the LEED.

Significance of Skeletal Muscle Loss in Liver Hypertrophy in Patients Undergoing Portal Vein Embolization Before Major Hepatectomy: Assessment With Body Composition and Nutritional Indicators.

BACKGROUND/AIM: The relationship between body composition including skeletal muscle and liver hypertrophy initiated by portal vein embolization (PVE) for major hepatectomy has not been clarified. This study aimed to investigate the effects of skeletal muscle, body adipose, and nutritional indicators on liver hypertrophy. PATIENTS AND METHODS: Fifty-nine patients who underwent PVE scheduled for major right-sided hepatectomy were included. The skeletal muscle area of L3 as skeletal muscle index was calculated. The relationship between skeletal muscle loss and clinical variables was assessed. We also evaluated the relationship between >30% liver growth or >12% liver growth/week after PVE. RESULTS: Skeletal muscle loss was observed in 39 patients (66.1%) and associated with zinc deficiency, visceral adipose index, liver growth rate, and liver growth rate/week. Multivariate analysis indicated that future liver volume and skeletal muscle index were associated with >30% liver growth, and functional future liver volume and skeletal muscle index were associated with >12% liver growth/week. CONCLUSION: Loss of skeletal muscle, and a small future remnant liver volume, attenuates liver hypertrophy initiated by PVE. Strength building and nutritional supplementation may have positive effects on liver hypertrophy after PVE.

Parenchyma-Sparing Liver Resection or Regenerative Liver Surgery: Which Way to Go?

Liver resection for malignant tumors should respect oncological margins while ensuring safety and improving the quality of life, therefore tumor staging, underlying liver disease and performance status should all be attentively assessed in the decision process. The concept of parenchyma-sparing liver surgery is nowadays used as an alternative to major hepatectomies to address deeply located lesions with intricate topography by means of complex multiplanar parenchyma-sparing liver resections, preferably under the guidance of intraoperative ultrasound. Regenerative liver surgery evolved as a liver growth induction method to increase resectability by stimulating the hypertrophy of the parenchyma intended to remain after resection (referred to as future liver remnant), achievable by portal vein embolization and liver venous deprivation as interventional approaches, and portal vein ligation and associating liver partition and portal vein ligation for staged hepatectomy as surgical techniques. Interestingly, although both strategies have the same conceptual origin, they eventually became caught in the never-ending parenchyma-sparing liver surgery vs. regenerative liver surgery debate. However, these strategies are both valid and must both be mastered and used to increase resectability. In our opinion, we consider parenchyma-sparing liver surgery along with techniques of complex liver resection and intraoperative ultrasound guidance the preferred strategy to treat liver tumors. In addition, liver volume-manipulating regenerative surgery should be employed when resectability needs to be extended beyond the possibilities of parenchyma-sparing liver surgery.

Evaluation method of ex vivo porcine liver reduced scattering coefficient during microwave ablation based on temperature.

The principle of microwave ablation (MWA) is to cause irreversible damage (protein coagulation, necrosis, etc.) to tumor cells at a certain temperature by heating, thereby destroying the tumor. We have long used functional near-infrared spectroscopy (fNIRs) to monitor clinical thermal ablation efficacy. After a lot of experimental verification, it can be found that there is a clear correlation between the reduced scattering coefficient and the degree of tissue damage. During the MWA process, the reduced scattering coefficient has a stable change. Therefore, both temperature (T) and reduced scattering coefficient ( µ s ' ) are related to the thermal damage of the tissue. This paper mainly studies the changing law of T and µ s ' during MWA and establishes a relationship model. The two-parameter simultaneous acquisition system was designed and used to obtain the T and µ s ' of the ex vivo porcine liver during MWA. The correlation model between T and µ s ' is established, enabling the quantitative estimation of µ s ' of porcine liver based on T. The maximum and the minimum relative errors of µ s ' are 79.01 and 0.39%, respectively. Through the electromagnetic simulation of the temperature field during MWA, 2D and 3D fields of reduced scattering coefficient can also be obtained using this correlation model. This study contributes to realize the preoperative simulation of the optical parameter field of microwave ablation and provide 2D/3D therapeutic effect for clinic.

En bloc excision of giant polycystic liver with hepatic cava and its auto-transplant caval reconstruction as a safe surgical procedure for liver transplantation.

Safely excising a giant liver while leaving the hepatic inferior vena cava intact is difficult. Hata et al. present images and videos describing their novel technique consisting of total hepatectomy including the hepatic cava; extracorporeal retrieval; and auto-transplant inferior vena cava reconstruction, for an extremely enlarged polycystic liver weighing 24 kg.

Massive cerebral air embolism following percutaneous transhepatic biliary drainage: A case report.

RATIONALE: Cerebral air embolism from portal venous gas rarely occurs due to invasive procedures (e.g., endoscopic procedures, liver biopsy, or percutaneous transhepatic biliary drainage) that disrupt the gastrointestinal or hepatobiliary structures. Here, we report a rare case of fatal cerebral air embolism following a series of percutaneous transhepatic biliary drainage tube insertions. PATIENT CONCERNS: A 50-year-old woman with a history of cholecystectomy, liver wedge resection, and hepaticojejunostomy for gallbladder cancer presented with altered mental status 1 week after percutaneous transhepatic biliary drainage tube placement. DIAGNOSES: Extensive cerebral air embolism and acute cerebral infarction. INTERVENTIONS: Brain computed tomography and magnetic resonance imaging, hyperbaric oxygen therapy, medical therapy. OUTCOMES: Despite the use of hyperbaric oxygen therapy and medical treatment including vasopressors, the patient eventually died due to massive systemic air embolism. LESSONS: To date, there have been no reports of cerebral air embolism due to percutaneous transhepatic biliary drainage with pronounced radiologic images. We reviewed previously reported fatal cases associated with endoscopic hepatobiliary procedures and assessed the possible mechanisms and potential causes of air embolism.

Investigation of Microwave Ablation Process in Sweet Potatoes as Substitute Liver.

The microwave ablation technique to destroy cancer tissues in liver is practiced clinically and is the subject of ongoing research, e.g., ablation monitoring. For studies, liver tissue from cattle or pigs is often used as a substitute material. In this work, sweet potato is presented as an alternative material for microwave ablation experiments in liver due to similar material properties. Sweet potatoes as a substitute for liver have the advantages of better handling, easy procurement and stable material properties over time for microwave ablation experiments. The dielectric constant and electrical conductivity of sweet potato are characterized for temperature variation with the help of high-temperature dielectric probe. Furthermore, a test setup is presented for microwave ablation experiments in which a bowtie slot antenna matched to sweet potato is placed on its surface to directly receive the microwave power from a self-developed microwave applicator inserted into a sweet potato 4 cm below the surface antenna. A high-power source was used to excite the microwave powers up to 80 W and a spectrum analyzer was used to measure the signal received by the surface antenna. The experiments were performed in an anechoic chamber for safety reasons. Power at 50 W and 80 W was stimulated for a maximum of 600 s at the 2.45 GHz ISM band in different sweet potato experiments. A correlation is found between the power received by the surface antenna and rise of temperature inside sweet potato; relative received power drops from 1 at 76 ∘C to 0.6 at 88 ∘C (max. temperature) represents a 40% relative change in a 50 W microwave ablation experiment. The received power envelope at the surface antenna is between 10 mW and 32 mW during 50 W microwave ablation. Other important results for 10 min, 80 W microwave ablation include: a maximum ablation zone short axis diameter of 4.5 cm and a maximum ablation temperature reached at 99 ∘C, 3 mm away from the applicator's slot. The results are compared with the state of the art in microwave ablation in animal liver. The dielectric constant and electrical conductivity evolution of sweet potato with rising temperature is comparable to animal liver in 50-60 ∘C range. The reflection loss of self-developed applicator in sweet potato is below 15 dB which is equal to reflection loss in liver experiments for 600 s. The temperature rise for the first 90 s in sweet potato is 76 ∘C as compared to 73 ∘C in liver with 50 W microwave ablation. Similarly, with 80-75 W microwave ablation, for the first 60 s, the temperature is 98 ∘C in sweet potato as compared to 100 ∘C in liver. The ablation zone short-axis diameter after 600 s is 3.3 cm for 50 W microwave ablation in sweet potato as compared to 3.5 cm for 30 W microwave ablation in liver. The reasons for difference in microwave ablation results in sweet potato and animal liver are discussed. This is the first study to directly receive a signal from microwave applicator during a microwave ablation process with the help of a surface antenna. The work can be extended to multiple array antennas for microwave ablation monitoring.

Astragaloside IV Suppresses Hepatic Proliferation in Regenerating Rat Liver after 70% Partial Hepatectomy via Down-Regulation of Cell Cycle Pathway and DNA Replication.

Astragaloside IV (AS-IV) is one of the major bio-active ingredients of huang qi which is the dried root of Astragalus membranaceus (a traditional Chinese medicinal plant). The pharmacological effects of AS-IV, including anti-oxidative, anti-cancer, and anti-diabetic effects have been actively studied, however, the effects of AS-IV on liver regeneration have not yet been fully described. Thus, the aim of this study was to explore the effects of AS-IV on regenerating liver after 70% partial hepatectomy (PHx) in rats. Differentially expressed mRNAs, proliferative marker and growth factors were analyzed. AS-IV (10 mg/kg) was administrated orally 2 h before surgery. We found 20 core genes showed effects of AS-IV, many of which were involved with functions related to DNA replication during cell division. AS-IV down-regulates MAPK signaling, PI3/Akt signaling, and cell cycle pathway. Hepatocyte growth factor (HGF) and cyclin D1 expression were also decreased by AS-IV administration. Transforming growth factor ß1 (TGFß1, growth regulation signal) was slightly increased. In short, AS-IV down-regulated proliferative signals and genes related to DNA replication. In conclusion, AS-IV showed anti-proliferative activity in regenerating liver tissue after 70% PHx.

Significance of liver resection for intermediate stage hepatocellular carcinoma according to subclassification.

BACKGROUND: Patients diagnosed with Barcelona Clinic Liver Cancer (BCLC) intermediate stage hepatocellular carcinoma (HCC) encompass a broad clinical population. Kinki criteria subclassifications have been proposed to better predict prognoses and determine appropriate treatment strategies for these patients. This study validated the prognostic significance within the Kinki criteria substages and analyzed the role of liver resection in patients with intermediate stage HCC. METHODS: Patients with intermediate stage HCC (n = 378) were retrospectively subclassified according to the Kinki criteria (B1, n = 123; B2, n = 225; and B3, n = 30). We analyzed the overall survival (OS) and treatment methods. RESULTS: The OS was significantly different between adjacent substages. Patients in substage B1 who underwent liver resection had a significantly better prognosis than those who did not, even after propensity score matching (PSM). Patients in substage B2 who underwent liver resection had a significantly better prognosis than those who did not; however, there was no difference after PSM. There was no difference in prognosis based on treatments among patients in substage B3. CONCLUSIONS: The Kinki criteria clearly stratify patients with intermediate stage HCC by prognosis. For substage B1 HCC patients, liver resection provides a better prognosis than other treatment modalities. In patients with substage B2 and B3, an alternative approach is required.

MR-guided microwave ablation of hepatocellular carcinoma (HCC): is general anesthesia more effective than local anesthesia?

BACKGROUND: Percutaneous magnetic resonance-guided (MR-guided) MWA procedures have traditionally been performed under local anesthesia (LA) and sedation. However, pain control is often difficult to manage, especially in some cases when the tumor is large or in a specific location, such as near the abdominal wall or close to the hepatic dome. This study retrospectively compared the results of general anesthesia (GA) and local anesthesia (LA) for MR-guided microwave ablation (MWA) in patients with hepatocellular carcinoma (HCC ≤ 5.0 cm) to investigate whether different anesthesia methods lead to different clinical outcomes. METHODS: The results of the analysis include procedure-related complications, imaging response, and the time to complete two sets of procedures. According to the type of anesthesia, the Kaplan-Meier method was used to compare the local tumor progression (LTP) of the two groups who underwent MR-guided MWA. RESULTS: All patients achieved technical success. The mean ablation duration of each patient in the GA group and LA group was remarkably different (P = 0.012). Both groups had no difference in complications or LTP (both P > 0.05). Notably, the tumor location (challenging locations) and the number of lesions (2-3 lesions) could be the main factors affecting LTP (p = 0.000, p = 0.015). Univariate Cox proportional hazard regression indicated that using different anesthesia methods (GA and LA) was not associated with longer LTP (P = 0.237), while tumor location (challenging locations) and the number of lesions (2-3 lesions) were both related to shorter LTP (P = 0.000, P = 0.020, respectively). Additionally, multivariate Cox regression further revealed that the tumor location (regular locations) and the number of lesions (single) could independently predict better LTP (P = 0.000, P = 0.005, respectively). CONCLUSIONS: No correlation was observed between GA and LA for LTP after MR-guided MWA. However, tumors in challenging locations and the number of lesions (2-3 lesions) appear to be the main factors affecting LTP.

[Advances in Ultrasound Tissue Characterization and Its Application in Thermal Ablation of Tumors].

The methods of monitoring the thermal ablation of tumor are compared and analyzed in recent years. The principle method results and insufficient of ultrasound elastography and quantitative ultrasound imaging are discussed. The results show that ultrasonic tissue signature has great development space in the field of real-time monitoring of thermal ablation, but there are still some problems such as insufficient monitoring accuracy difficulty in whole-course monitoring and insufficient in vivo experiments, so it is impossible to realize clinical application. It is necessary to further study the monitoring method which can realize accurate and real-time detection of ablation zone and transition zone and can be easily combined with the existing ultrasonic equipment.

Discontinuous moving shot technique for conformal thermal ablation in an ex vivo porcine liver model.

PURPOSE: We aimed to determine the ablation characteristics of discontinuous moving shot technique (DMST) in microwave ablation (MWA), radiofrequency ablation (RFA) and laser ablation (LA), and analyze the differences compared with fixed electrode technique (FET) in an ex vivo porcine liver model. METHODS: FET was defined as the ablation needle remaining fixed during ablation. In DMST, ablation needle moved backward for a fixed distance twice along the long axis during ablation. Four moving distances (0.5 cm, 0.75 cm, 1 cm and 2 cm) were used in DMST. Long-axis diameter (LAD) and short-axis diameter (SAD) of ablation zones were measured. The ratio of LAD/SAD was calculated. RESULTS: The shape and size of ablation zones were different between DMST and FET. Compared with FET, DMST could achieve greater LAD when the moving distance became long enough. In MWA with DMST, SAD decreased with the extension of moving distance and finally became smaller than the SAD in FET. While in LA and RFA, the change of moving distance did not affect SAD significantly. CONCLUSION: In MWA, RFA and LA, the characteristics of ablation zone of DMST were different from that of FET. This unique ablation technique may be suitable for conformal thermal ablation.

Pattern of thermal damage and tissue carbonisation from endovenous radiofrequency ablation catheter - Using an in vitro porcine liver model.

BACKGROUND: Successful endovenous thermoablation relies on transmural vein wall ablation. We investigated the pattern of thermal spread and tissue carbonisation from RadioFrequency-induced ThermoTherapy (RFiTT) at different powers and pull back methods, using a porcine liver model. METHODS: We used a previously validated in-vitro porcine liver model. Different powers from 5-25 W were used to administer 150 J. We compared continuous and pulsed energy delivery. Length, lateral spread, and total area of thermal damage, together with any tissue carbonisation, was measured using digital analysis software. RESULTS: All experiments used 150 J total energy. Total thermal damage area was smaller with lower power and pulsed energy. Continuous energy caused more tissue carbonisation than pulsed except at 25 W. CONCLUSION: Reduced thermal damage with lower power or pulsed energy results from cooling due to increased time of treatment. Increasing the power increases tissue carbonisation. Optimal treatment is determined by the highest power used continuously that does not cause tissue carbonisation.

Advances in Ultrasound Tissue Characterization and Its Application in Thermal Ablation of Tumors / 中国医疗器械杂志

The methods of monitoring the thermal ablation of tumor are compared and analyzed in recent years. The principle method results and insufficient of ultrasound elastography and quantitative ultrasound imaging are discussed. The results show that ultrasonic tissue signature has great development space in the field of real-time monitoring of thermal ablation, but there are still some problems such as insufficient monitoring accuracy difficulty in whole-course monitoring and insufficient

Tissue characterization utilizing hyperspectral imaging for liver thermal ablation.

BACKGROUND: Thermal ablation is the dominant modality to treat liver tumors for patients who are not surgical candidates. . However, correctly predicting the volume of the subsequent tissue destruction during the Thermal Ablation technique is a difficult undertaking. OBJECTIVE: To examine the impacts of ablation zone volume following Radiofrequency ablation (RFA) of an ex-vivo bovine liver to correlate the impacts of thermal ablation with target organ perfusion; by exploiting the unique properties of Hyperspectral Imaging (HSI). MATERIALS AND METHODS: Radiofrequency ablation was perfused on ex-vivo bovine livers at peripheral and central­vessel­adjacent locations, and monitored by HSI with a spectral range from 400 to 1000 nm. The system contains k-means clustering (K = 8) algorithms combining spectral and spatial information. Labeled spectral signatures datasets were used as training data. Statistical analysis (10 samples) was computed to calculate the highest variance between six spectral images for determining the optimum wavelength for discrimination between the affected regions after thermal ablation (normal, thermal, and ablated liver tissue regions). RESULTS: The change of the optical properties ofex-vivo liver tissues provides different responses to light transmission, scattering, absorption and particularly the reflection over the spectrum range. The produced spectral image from reflection with the highest variance (358.07) empowered us to determine the optimum wavelength spectral image (720 ±â€¯18.92 nm) to distinguish between the normal, ablated, and thermal categories. CONCLUSION: Hyperspectral imaging is a powerful tool in monitoring tissue characterization, which is a useful technique for edge evaluation of liver thermal ablation ..