Liver volume measurement: reason of the difference between in vivo CT-volumetry and intraoperative ex vivo determination and how to cope it

Histology-based quantification of boiling histotripsy outcomes via ResNet-18 network: Towards mechanical dose metrics

This work was focused on the newly developed ultrasonic approach for non-invasive surgery - boiling histotripsy (BH) - recently proposed for mechanical ablation of tissues using pulsed high intensity focused ultrasound (HIFU). The BH lesion is known to depend in size and shape on exposure parameters and mechanical properties, structure and composition of tissue being treated. The aim of this work was to advance the concept of BH dose by investigating quantitative relationships between the parameters of the lesion, pulsing protocols, and targeted tissue properties. A HIFU focus of a 1.5 MHz 256-element array driven by power-enhanced Verasonics system was electronically steered along the grid within 12 × 4 × 12 mm volume to produce volumetric lesions in porcine liver (soft, with abundant collagenous structures) and bovine myocardium (stiff, homogenous cellular) ex vivo tissues with various pulsing protocols (1-10 ms pulses, 1-15 pulses per point). Quantification of the lesion size and completeness was performed through serial histological sectioning, and a computer vision approach using a combination of manual and automated detection of fully fractionated and residual tissue based on neural network ResNet-18 was developed. Histological sample fixation led to underestimation of BH ablation rate compared to the ultrasound-based estimations, and provided similar qualitative feedback as did gross inspection. This suggests that gross observation may be sufficient for qualitatively evaluating the BH treatment completeness. BH efficiency in liver tissue was shown to be insensitive to the changes in pulsing protocol within the tested parameter range, whereas in bovine myocardium the efficiency increased with either increasing pulse length or number of pulses per point or both. The results imply that one universal mechanical dose metric applicable to an arbitrary tissue type is unlikely to be established. The dose metric as a product of the BH pulse duration and the number of pulses per sonication point (BHD1) was shown to be more relevant for initial planning of fractionation of collagenous tissues. The dose metric as a number of pulses per point (BHD2) is more suitable for the treatment planning of softer targets primarily containing cellular tissue, allowing for significant acceleration of treatment using shorter pulses.

[90Y]Yttria Alumino Silicate Glass Microspheres: A Biosimilar Formulation to "TheraSphere" for Cost-Effective Treatment of Liver Cancer

Background: Selective internal radiation therapy (SIRT) using a suitable β--emitting radionuclide is a promising treatment modality for unresectable liver carcinoma. Yttrium-90 (90Y) [T1/2 = 64.2 h, Eβ(max) = 2.28 MeV, no detectable γ-photon] is the most preferred radioisotope for SIRT owing to its favorable decay characteristics. Objective: The present study describes indigenous development and evaluation of intrinsically radiolabeled [90Y]yttria alumino silicate ([90Y]YAS) glass microsphere, a formulation biosimilar to "TheraSphere" (commercially available, U.S. FDA-approved formulation), for SIRT of unresectable liver carcinoma in human patients. Methods: YAS glass microspheres of composition 40Y2O3-20Al2O3-40SiO2 (w/w) and diameter ranging between 20 and 36 μm were synthesized with almost 100% conversion efficiency and >99% sphericity. Intrinsically labeled [90Y]YAS glass microspheres were produced by thermal neutron irradiation of cold YAS glass microspheres in a research reactor. Subsequent to in vitro evaluations and in vivo studies in healthy Wistar rats, customized doses of [90Y]YAS glass microspheres were administered in human patients. Results: [90Y]YAS glass microspheres were produced with 137.7 ± 8.6 MBq/mg YAS glass (∼6800 Bq per microsphere) specific activity and 99.94% ± 0.02% radionuclidic purity at the end of irradiation. The formulation exhibited excellent in vitro stability in human serum and showed >97% retention in the liver up to 7 d post-administration when biodistribution studies were carried out in healthy Wistar rats. Yttrium-90 positron emission tomography scans recorded at different time points post-administration of customized dose of [90Y]YAS glass microspheres in human patients showed near-quantitative retention of the formulation in the injected lobe. Conclusions: The study confirmed the suitability of indigenously prepared [90Y]YAS glass microspheres for clinical use in the treatment of unresectable hepatocellular carcinoma.

Manual and semi-automated computed tomography volumetry significantly overestimates the right liver lobe graft weight: a single-center study with adult living liver donors

PURPOSE

Preoperative evaluation of donor liver volume is indispensable in living donor liver transplantation to ensure sufficient residual liver and graft-to-recipient weight ratio. This study aims to evaluate the accuracy of two computed tomography (CT) volumetry programs, an interactive manual and a semi-automated one, in the preoperative estimation of the right lobe graft weight.

METHODS

One hundred and nine right liver lobe living donors between January 2008 and January 2020 were enrolled in this retrospective study. Two radiologists measured the liver graft volumes independently using manual and semi-automated CT volumetry, and the interaction time was recorded. Actual graft weight (AGW) measured intraoperatively served as the reference standard. The paired samples t-test was used to compare the estimated graft weight (EGW) and the AGW. Inter-user and inter-method agreements were assessed with Bland-Altman plots.

RESULTS

Both manual and semi-automated CT volumetry significantly overestimated the graft weight (EGW manual: 893 ± 155 mL vs. AGW manual: 787 ± 128 g, P < 0.001, EGW semi-automated: 879 ± 143 mL vs. AGW semi-automated, P < 0.001). The junior radiologist measured higher volumes than the senior radiologist with either method (P < 0.001). The Bland-Altman analysis revealed mean difference and standard deviation for inter-method agreement of 7 ± 48 cc for the senior radiologist, and 34 ± 54 cc for the junior radiologist. The mean difference and standard deviation for inter-method agreement was 63 ± 59 cc in manual volumetry and 22 ± 38 cc in semi-automated volumetry. The mean interaction time was 27.3 ± 14.2 min for manual volumetry and 6.8 ± 1.4 min for semi-automated volumetry (P < 0.001).

CONCLUSION

Both manual and semi-automated CT volumetry significantly overestimated the right liver graft weight, while semi-automated volumetry significantly reduced the interaction time.

Is an intraoperative liver function assessment possible? Application of the 13C-methacetin-breath-test during major liver resections - a pilot study

BACKGROUND

As prevention of posthepatectomy-liver-failure is crucial, there is need of dynamic assessment of liver function, even intraoperatively. 13C-methacetin-breath-test estimates the organ's microsomal functional capacity. This is its first intraoperative evaluation in major liver surgery.

METHODS

30 patients planed for resection of ≥3 liver segments, between March-November 2019, were prospectively enrolled in this "single-center", pilot study. Using the 13C-methacetin-breath-test, liver function was assessed four times: preoperatively, intraoperatively before and after resection and postoperatively. The resulted maximum-liver-function-capacity (LiMAx)-values and delta-over-baseline (DOB)-curves were compared, further analyzed and correlated to respective liver volumes.

RESULTS

The intraoperative LiMAx-values before resection were mostly lower than the preoperative ones (-11.3% ± 28%). The intraoperative measurements after resection resulted to mostly higher values than the postoperative ones (42.35% ± 46.19%). Pharmacokinetically, an interference between the two intraoperative tests was observed. There was no strong correlation between residual liver volume and function with a percentual residual-LiMAx mostly lower than the percentual residual volume (-17.7% ± 4.1%).

CONCLUSIONS

Intraoperative application of the 13C-methacetin-breath-test during major liver resections seems to deliver lower values than the standard preoperative test. As multiple intraoperative tests interfere significantly to each other, a single intraoperative measurement is suggested. Multicentric standardized measurements could define the "normal" range for intraoperative measurements and control their predictive value.

Swine Partial Liver Transplantation Model for Practicing Living Donor Liver Transplantation Based on a New Liver Segmentation Method

BACKGROUND

Living donor liver transplantation (LDLT) is one of the most technically demanding and complicated procedures. However, unlike deceased donor liver transplantation, there is no suitable animal model for practicing LDLT. Herein, we propose a new liver segmentation method and a feasible pig LDLT model for practicing for LDLT in humans.

METHODS

Four Landrace pigs weighing 25, 25, 27, and 28 kg were used as donors and recipients to establish a partial liver transplantation model. Partial liver transplantation was performed using a right liver and a left liver, respectively, based on a new segmentation system compatible with that of humans.

RESULTS

We established a new segmentation system for porcine liver transplantation and a partial liver transplantation model. For right liver transplantation, 91 and 142 min were required to operate on the donor and recipient, respectively; for left liver transplantation, 57 and 104 min were required to operate on the donor and recipient, respectively. All pigs that underwent partial liver transplantation remained alive until the operation was completed.

CONCLUSIONS

It is expected that this new pig model based on the new segmentation system will be suitable as an educational tool for LDLT training and will replace the existing animal models for partial liver transplantation.

Volumetric assessment of hepatic grafts using a light detection and ranging system for 3D scanning: Preliminary data

BACKGROUND

Liver transplantation has evolved into a safe life-saving operation and remains the golden standard in the treatment of end stage liver disease. The main limiting factor in the application of liver transplantation is graft shortage. Many strategies have been developed in order to alleviate graft shortage, such as living donor partial liver transplantation and split liver transplantation for adult and pediatric patients. In these strategies, liver volume assessment is of paramount importance, as size mismatch can have severe consequences in the success of liver transplantation.

AIM

To evaluate the safety, feasibility, and accuracy of light detection and ranging (LIDAR) 3D photography in the prediction of whole liver graft volume and mass.

METHODS

Seven liver grafts procured for orthotopic liver transplantation from brain deceased donors were prospectively measured with an LIDAR handheld camera and their mass was calculated and compared to their actual weight.

RESULTS

The mean error of all measurements was 17.03 g (range 3.56-59.33 g). Statistical analysis of the data yielded a Pearson correlation coefficient index of 0.9968, indicating a strong correlation between the values and a Student’s t-test P value of 0.26. Mean accuracy of the measurements was calculated at 97.88%.

CONCLUSION

Our preliminary data indicate that LIDAR scanning of liver grafts is a safe, cost-effective, and feasible method of ex vivo determination of whole liver volume and mass. More data are needed to determine the precision and accuracy of this method.

Prediction of Pharmacokinetics of IDP-73152 in Humans Using Physiologically-Based Pharmacokinetics

IDP-73152, a novel peptide deformylase inhibitor with an antibacterial effect against Gram-positive bacteria, is in phase I development. The objective of this study was to develop a physiologically-based pharmacokinetic model (PBPK) for IDP-73152 in animals, and to extend the model to humans. Biopharmaceutical properties of IDP-73152 are determined using in vitro/in vivo experimentations for the PBPK model. A transit model consisting of gastrointestinal segments is applied for an estimation of the intestinal absorption kinetics. The PBPK model of IDP-73152 in rats is able to appropriately predict the plasma concentration–time profiles after the administration of IDP-73152 at different doses and by different routes (combined absolute average fold error (cAAFE), 1.77). The model is also found to be adequate in predicting the plasma concentration–time profiles of IDP-73152 in mice (cAAFE 1.59) and dogs (cAAFE 1.42). Assuming the oral administration of IDP-73152 to humans at doses of 640 and 1280 mg, the model is able to reproduce the concentration–time profiles obtained in humans (cAAFE 1.38); therefore, these observations indicate that the PBPK model used for IDP-73152 is applicable to animal species and humans. This model may be useful in predicting efficacious doses of IDP-73152 for the management of infectious disease in humans.

Role of CT in Two-Stage Liver Surgery

Complete resection is the only potentially curative treatment for primary or metastatic liver tumors. Improvements in surgical techniques such as conventional two-stage hepatectomy (TSH) with portal vein embolization and ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) promote hypertrophy of the future liver remnant (FLR), expanding resection criteria to include patients with widespread hepatic disease who were formerly not considered candidates for resection. Radiologists are essential in the multidisciplinary approach required for TSH. In particular, multidetector CT has a critical role throughout the various stages of this surgical process. The aims of CT before the first stage of TSH are to define the feasibility of surgery, assess the number and location of liver tumors in relation to relevant anatomy, and provide a detailed anatomic evaluation, including vascular and biliary variants. Volume calculation with CT is also essential to determine if the FLR is sufficient to avoid posthepatectomy liver failure. The objectives of CT between the first and second stages of TSH are to recalculate liver volumes (ie, assess FLR hypertrophy) and depict expected liver changes and complications that could modify the surgical plan or preclude the second stage of definitive resection. In this review, the importance of CT throughout different stages of TSH is discussed and key observations that contribute to surgical planning are highlighted. In addition, the advantages and limitations of MRI for detection of liver metastases and assessment of complications are briefly described. ^©RSNA, 2022.

Left lateral segment liver volume is not correlated with anthropometric measures

BACKGROUND

Liver transplantation is definitive therapy for end stage liver disease in pediatric patients. Living donor liver transplantation (LDLT) with the left lateral segment (LLS) is often a feasible option. However, the size of LLS is an important factor in donor suitability - particularly when the recipient weighs less than 10 kg. In the present study, we sought to define a formula for estimating left lateral segment volume (LLSV) in potential LLS donors.

METHODS

We obtained demographic and anthropometric measurements on 50 patients with Computed Tomography (CT) scans to determine whole liver volume (WLV), right liver volume (RLV), and LLSV. We performed univariable and multivariable linear regression with backwards stepwise variable selection (p < 0.10) to determine final models.

RESULTS

Our study found that previously reported anthropometric and demographics variables correlated with volume were significantly associated with WLV and RLV. On univariable analysis, no demographic or anthropometric measures were correlated with LLSV. On multivariable analysis, LLSV was poorly predicted by the final model (R2 = 0.10, Coefficient of Variation [CV] = 42.2) relative to WLV (R2 = 0.33, CV = 18.8) and RLV (R2 = 0.41, CV = 15.8).

CONCLUSION

Potential LLS living donors should not be excluded based on anthropometric data: all potential donors should be evaluated regardless of their size.

Investigation of the Feasibility of Ventricular Delivery of Resveratrol to the Microelectrode Tissue Interface

(1) Background: Intracortical microelectrodes (IMEs) are essential to basic brain research and clinical brain-machine interfacing applications. However, the foreign body response to IMEs results in chronic inflammation and an increase in levels of reactive oxygen and nitrogen species (ROS/RNS). The current study builds on our previous work, by testing a new delivery method of a promising antioxidant as a means of extending intracortical microelectrodes performance. While resveratrol has shown efficacy in improving tissue response, chronic delivery has proven difficult because of its low solubility in water and low bioavailability due to extensive first pass metabolism. (2) Methods: Investigation of an intraventricular delivery of resveratrol in rats was performed herein to circumvent bioavailability hurdles of resveratrol delivery to the brain. (3) Results: Intraventricular delivery of resveratrol in rats delivered resveratrol to the electrode interface. However, intraventricular delivery did not have a significant impact on electrophysiological recordings over the six-week study. Histological findings indicated that rats receiving intraventricular delivery of resveratrol had a decrease of oxidative stress, yet other biomarkers of inflammation were found to be not significantly different from control groups. However, investigation of the bioavailability of resveratrol indicated a decrease in resveratrol accumulation in the brain with time coupled with inconsistent drug elution from the cannulas. Further inspection showed that there may be tissue or cellular debris clogging the cannulas, resulting in variable elution, which may have impacted the results of the study. (4) Conclusions: These results indicate that the intraventricular delivery approach described herein needs further optimization, or may not be well suited for this application.

Morphologic Change of In Vivo Porcine Liver Under 13 mm Hg Pneumoperitoneum Pressure

BACKGROUND

Clinically, the total and residual liver volume must be accurately calculated before major hepatectomy. However, liver volume might be influenced by pneumoperitoneum during surgery. Changes in liver volume change also affect the accuracy of simulation and augmented reality navigation systems, which are commonly first validated in animal models. In this study, the morphologic changes in porcine livers in vivo under 13 mm Hg pneumoperitoneum pressure were investigated.

MATERIALS AND METHODS

Twenty male pigs were scanned with contrast-enhanced computed tomography without pneumoperitoneum and with 13 mm Hg pneumoperitoneum pressure.

RESULTS

The surface area and volume of the liver and the vascular diameter of the aortic lumen, inferior vena cava lumen, and portal vein lumen were measured. There were statistically significant differences in the surface area and volume of the liver (P=0.000), transverse diameter of the portal vein (P=0.038), longitudinal diameter of the inferior vena cava (P=0.033), longitudinal diameter of the portal vein (P=0.036), vascular cross-sectional area of the inferior vena cava (P=0.028), and portal vein (P=0.038) before and after 13 mm Hg pneumoperitoneum pressure.

CONCLUSIONS

This study indicated that the creation of pneumoperitoneum at 13 mm Hg pressure in a porcine causes liver morphologic alterations affecting the area and volume, as well as the diameter of a blood vessel.

Unraveling Congener-Specific Transfer of Non-Dioxin-Like Polychlorinated Biphenyls (ndl-PCBs) from Feed into Chicken Meat

Non-dioxin-like polychlorinated biphenyls (ndl-PCBs) are a subclass of persistent bioaccumulative pollutants able to enter the food chain. We investigated the transfer of ndl-PCBs from contaminated feed into meat and liver of fattening chickens. A total of 48 chicks were divided into five treatment and one control groups. Treated animals were fed with contaminated diets (11.7 ± 0.4 μg/kg sum of indicator ndl-PCBs; 88% dry matter (DM)) before slaughter for different subperiods of time: 16, 23, 28, 32, and 36 days for groups 1-5, respectively. One day after the end of each subperiod, three animals per group were slaughtered to determine the congener-specific ndl-PCB content. All remaining animals were fed the control feed until slaughter on day 37 to probe depuration. We used these data to generate congener-specific physiologically based toxicokinetic (PBTK) models for indicator ndl-PCBs. The models show that PCBs 28, 138, 153, and 180 form a more slowly eliminated cluster (with an observed transfer rate into meat over 74% and observed half-lives over 8.7 days) than PCBs 52 and 101 (with a transfer rate under 13% and half-lives under 2.6 days). Our simulations show that ndl-PCB levels in feed lower than 3.9 (long 56-day) or 4.4 μg/kg (short 37-day fattening period) would be necessary to ensure the current maximum level in muscle meat (fat basis), according to EU Regulations 1881/2006 and 1259/2011. The PBTK models are made available in the Python and Food Safety Knowledge Exchange formats.

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.

Robotic Versus Open Liver Resection in Hepatocarcinoma: Surgical and Oncological Outcomes

BACKGROUND

Minimally invasive approaches are spreading in every field of surgery, including liver surgery. However, studies comparing robotic hepatectomy with the conventional open approach regarding oncologic outcomes for hepatocellular carcinoma are limited.

MATERIALS AND METHODS

We retrospectively reviewed demographics characteristics, pathologic features, surgical, and oncological outcomes of patients who underwent robotic and conventional open liver resection for hepatocellular carcinoma.

RESULTS

No significant differences in demographics features, tumor size, tumor location, and type of liver resection were found. The morbidity rate was similar, 23% for the open group versus 17% of the robotic group (P=0.605). Perioperative data analysis showed a greater estimated blood loss in patients who underwent open resection, if compared with robotic group (P=0.003). R0 resection and disease-free resection margins showed no statistically significant differences. The 3-year disease-free survival of the robotic group was comparable with that of the open group (54% vs. 37%; P=0.592), as was the 3-year overall survival (87% vs. 78%; P=0.203).

CONCLUSIONS

The surgical and the oncological outcomes seem to be comparable between minimally invasive and open hepatectomy. Robotic liver resections are effective, and do not compromise the oncological outcome, representing a reasonable alternative to the open approach.

A Validation Study of Liver Volumetry Estimation by a Semiautomated Software in Patients Undergoing Hepatic Resections

Purpose The purpose of this study was to validate the use of a semiautomated software for liver volumetry preoperatively by comparing it with the volume of resected specimen in patients undergoing hepatic resections.

Materials and Methods This is a single-center retrospective study of patients who underwent estimation of future liver remnant (FLR) using Myrian XP-Liver which is a semiautomated software for hepatectomy. The estimated resection volume, which is the sum of volume of normal liver to be resected and tumor volume, was compared with actual specimen weight to calculate the accuracy of the software. The statistical analysis was performed with SPSS software version 24.

Results Data on FLR estimation using the semiautomated software was available for 200 out of 388 patients who underwent formal hepatic resections. The median resected volume of surgical specimen was 650 mL (interquartile range [IQR] 364–950), while the median estimated volume using the Myrian software was 617 mL (IQR 362–979). There was significant correlation between estimated resection volume calculated using the semiautomated method and actual specimen weight (p-value < 0.0001) with the Spearman’s correlation value of 0.956.

Conclusion The estimated volume of liver to be resected as calculated by the semiautomated software was accurate and correlated significantly with the volume of resected specimen, and hence, the estimation of FLR volume may likely correlate with the true postoperative residual liver volume. In addition, the software-based liver segmentation, FLR estimation, and color-coded three-dimensional images provide a clear road map to the surgeon to facilitate safe resection.

Study of factors affecting Small for Size Syndrome Post-Adult living donor liver transplantation

AIM

Recently, increasing evidence showed that small-for-size syndrome (SFSS) is a multifactorial disease which is precipitated by various perioperative factors other than graft size. We conducted the current work to evaluate perioperative effectors, which can increase the risk of SFSS following adult living-donor liver transplantation (LDLT).

METHODS

This is a retrospective study on 110 adult cirrhotic cases (mean age of 48.4 ± 6.9 years old) who underwent adult LDLT. Most cases were males (89%). Cases were categorized into two groups based on the occurrence of SFSS. The groups were compared regarding preoperative (gender, age, comorbidities, baseline investigations), intraoperative (mean blood pressure and glucose; mean operation time; number of packed red cells, plasma, platelets, and cryoprecipitate units; time of cold and warm ischemia, and anhepatic phase; preclamping and post-reperfusion portal pressures), and postoperative factors (relevant investigations, hospital stay).

RESULTS

Postoperatively, 23 patients developed SFSS (20.9%). SFSS group had significantly lower preoperative graft recipient weight ratio (GRWR) (0.76 ± 0.1% versus 1.03 ± 0.15, respectively; p < 0.001), and elevated MELD scores (19 ± 2.1 versus 17.9 ± 4; p = 0.024). Preclamping and post-reperfusion portal pressures of ≥22.5 and 17.5 mmHg, exhibited a sensitivity of 95.7% and 91.3% and specificity of 87.4% and 88.9% respectively, for SFSS prediction.

CONCLUSION

SFSS risk is significantly linked to GRWR, MELD score, and intraoperative portal haemodynamics. Intraoperative portal haemodynamics exhibited good diagnostic accuracy for SFSS prediction and represented promising indicators for the prediction of SFSS.

The predictive value of future liver remnant function after liver resection for HCC in noncirrhotic and cirrhotic patients

BACKGROUND

Surgical procedures in patients with underlying liver disease are still burdened by a high rate of postoperative morbidity, especially posthepatectomy liver failure (PHLF), ranging from 1.2 to 33.8%. The aim of this study was to investigate the prognostic value of volume/function analysis for the prediction of hepatectomy-related morbidity in patients with hepatocellular carcinoma.

METHODS

Clinicopathological data were analysed in 261 patients who underwent liver resection for HCC between 2001 and 2014. Future liver remnant volume (FLRV) and future liver remnant function (FLRF) based on LiMAx test were obtained retrospectively. A subgroup analysis for high-risk patients with impaired liver function was conducted. Univariate and multivariate regression analysis was performed to identify risk factors for major complications, defined by Dindo ≥ IIIb and PHLF grade ≥ B.

RESULTS

In the total cohort, FLRF was independently associated with major complications. FLRV, resected liver volume, and FLRF were independent risk factors for PHLF. In a subgroup analysis of high-risk patients, FLRF was identified as the only independent risk factor for major complications and PHLF development.

DISCUSSION

These results suggest the superior value of FLRF to FLRV in predicting postoperative complications as well as PHLF in patients with chronic liver disease.

Semi-automated computed tomography Volumetry can predict hemihepatectomy specimens' volumes in patients with hepatic malignancy

Background

One of the major causes of perioperative mortality of patients undergoing major hepatic resections is post-hepatectomy liver failure (PHLF). For preoperative appraisal of the risk of PHLF it is important to accurately predict resectate volume and future liver remnant volume (FLRV). The objective of our study is to prospectively evaluate the accuracy of hemihepatectomy resectate volumes that are determined by computed tomography volumetry (CTV) when compared with intraoperatively measured volumes and weights as gold standard in patients undergoing hemihepatectomy.

Methods

Twenty four patients (13 women, 11 men) scheduled for hemihepatectomy due to histologically proven primary or secondary hepatic malignancies were included in our study. CTV was performed using a semi-automated module (S, hereinafter) (syngo.CT Liver Analysis VA30, Siemens Healthcare, Germany). Conversion factors between CT volumes on the one side and intraoperative volumes and weights on the other side were calculated using the method of least squares. Absolute and relative disagreements between CT volumes and intraoperative volumes were determined.

Results

A conversion factor of c = 0.906 most precisely predicted intraoperative volumes of exsanguinated hemihepatectomy specimens from CT volumes in all patients with mean absolute and relative disagreements between CT volumes and intraoperative volumes of 57 ml and 6.3%. The use of operation-specific conversion factors yielded even better results.

Conclusions

CTV performed with S accurately predicts intraoperative volumes of hemihepatectomy specimens when applying conversion factors which compensate for exsanguination. This allows to precisely estimate the FLRV and thus minimize the risk of PHLF in patients undergoing major hepatic resections.

Should We Have Blind Faith in Liver Volumetry?

Introduction: Liver volumetry is a routine procedure performed before major hepatectomy or living donor liver transplantation (LDLT) to anticipate the remnant liver volume and prevent liver failure. However, many parameters may impact its accuracy and no large-scale studies have evaluated inter-rater variabilities. We aimed to determine the reliability of volumetric assessments for whole organs in deceased-donor liver transplantations (DDLT) and partial organs in LDLT settings. Patients & Methods: Eight operators (four surgeons + four radiologists) analysed 30 preoperative CT scans (15 whole cirrhotic livers in the DDLT group + 15 partial healthy grafts in the LDLT group), using five software systems. The computed volumes were compared with liver weight; liver density being considered as1. Results: Inter-rater and inter-software concordances were excellent with coefficients of correlation >0.9. However, calculations overestimated the real volumes in 25 cases by a mean of 249 ± 206 [14-771] cc in the DDLT group and 138 ± 92cc [39-375] in the LDLT group. The mean calculations were significantly higher than liver weights in the LDLT group only (p=0.04). The radiologists overestimated the surgeons’ assessment in 24 cases, the differences exceeding 6% in some cases. The type of software used significantly impacted results in the DDLTgroup. Conclusions: Despite its unanimously recognised utility, we highlight significant discrepancies between estimated and real liver volumes. The global overestimation may lead to leave of too small remnant liver, with potentially dramatic consequences. In case of border-line estimations, we recommend a repetition of the evaluation by another operator (surgeon + radiologist working in concert).

Liver Transplantation and Liver Resection for Cirrhotic Patients with Hepatocellular Carcinoma: Comparison of Long-Term Survivals

BACKGROUND

Both liver transplantation (LT) and liver resection (LR) represent curative treatment options for hepatocellular carcinoma (HCC) in patients with liver cirrhosis. In this study, we have compared outcomes between historical and more recent patient cohorts scheduled either for LT or LR, respectively.

METHODS

Clinicopathological data of all patients with HCC and cirrhosis who underwent LT or LR between 1989 and 2011 were evaluated. Overall survival of patients with HCC within the Milan criteria (MC) was analyzed focusing on changes between different time periods.

RESULTS

In total, 364 and 141 patients underwent LT and LR for HCC in cirrhosis, respectively. Among patients with HCC within MC, 214 and 59 underwent LT and LR, respectively. Postoperative morbidity (37 vs. 11%, P < .0001), but not mortality (3 vs. 1%, P = .165), was higher after LR than after LT for HCC within MC. In the period 1989-2004, overall survival (OS) was significantly higher in patients who underwent LT compared to LR for HCC within MC (5-year OS: 77 vs. 36%, P < .0001). Interestingly, in the more recent period 2005-2011, OS was comparable between LT and LR for HCC within MC (5-year OS: 73 vs. 61%, P = .07).

CONCLUSION

We have noted an improvement of outcomes among patients selected for partial hepatectomy in recent years that were comparable to stable results after LT in cirrhotic patients with HCC. Whether those improvements are due to advances in liver surgery, optimized perioperative managament for patients with liver cirrhosis, and the development of modern multimodal treatment strategies for the recurrent lesions appears plausible.

Modeling liver electrical conductivity during hypertonic injection

Metastases in the liver frequently grow as scattered tumor nodules that neither can be removed by surgical resection nor focally ablated. Previously, we have proposed a novel technique based on irreversible electroporation that may be able to simultaneously treat all nodules in the liver while sparing healthy tissue. The proposed technique requires increasing the electrical conductivity of healthy liver by injecting a hypersaline solution through the portal vein. Aiming to assess the capability of increasing the global conductivity of the liver by means of hypersaline fluids, here, it is presented a mathematical model that estimates the NaCl distribution within the liver and the resulting conductivity change. The model fuses well-established compartmental pharmacokinetic models of the organ with saline injection models used for resuscitation treatments, and it considers changes in sinusoidal blood viscosity because of the hypertonicity of the solution. Here, it is also described a pilot experimental study in pigs in which different volumes of NaCl 20% (from 100 to 200 mL) were injected through the portal vein at different flow rates (from 53 to 171 mL/minute). The in vivo conductivity results fit those obtained by the model, both quantitatively and qualitatively, being able to predict the maximum conductivity with a 14.6% average relative error. The maximum conductivity value was 0.44 second/m, which corresponds to increasing 4 times the mean basal conductivity (0.11 second/m). The results suggest that the presented model is well suited for predicting on liver conductivity changes during hypertonic saline injection.

A Formula to Calculate Standard Liver Volume Using Thoracoabdominal Circumference

Background

With the use of split liver grafts as well as living donor liver transplantation (LDLT) it is imperative to know the minimum graft volume to avoid complications. Most current formulas to predict standard liver volume (SLV) rely on weight-based measures that are likely inaccurate in the setting of cirrhosis. Therefore, we sought to create a formula for estimating SLV without weight-based covariates.

Methods

LDLT donors underwent computed tomography scan volumetric evaluation of their livers. An optimal formula for calculating SLV using the anthropomorphic measure thoracoabdominal circumference (TAC) was determined using leave-one-out cross-validation. The ability of this formula to correctly predict liver volume was checked against other existing formulas by analysis of variance. The ability of the formula to predict small grafts in LDLT was evaluated by exact logistic regression.

Results

The optimal formula using TAC was determined to be SLV = (TAC × 3.5816) − (Age × 3.9844) − (Sex × 109.7386) − 934.5949. When compared to historic formulas, the current formula was the only one which was not significantly different than computed tomography determined liver volumes when compared by analysis of variance with Dunnett posttest. When evaluating the ability of the formula to predict small for size syndrome, many (10/16) of the formulas tested had significant results by exact logistic regression, with our formula predicting small for size syndrome with an odds ratio of 7.94 (95% confidence interval, 1.23-91.36; P = 0.025).

Conclusion

We report a formula for calculating SLV that does not rely on weight-based variables that has good ability to predict SLV and identify patients with potentially small grafts.

Adult living donor liver imaging

Adult living donor liver transplantation (LDLT) is increasingly used for the treatment of end-stage liver disease. The three most commonly harvested grafts for LDLT are left lateral segment, left lobe, and right lobe grafts. The left lateral segment graft, which includes Couinaud's segments II and III, is usually used for pediatric recipients or small size recipients. Most of the adult recipients need either a left or a right lobe graft. Whether a left or right lobe graft should be harvested from the donors depends on estimated graft and donor remnant liver volume, as well as biliary and vascular anatomy. Detailed preoperative assessment of the potential donor liver volumetrics, biliary and vascular anatomy, and liver parenchyma is vital to minimize risks to the donors and maximize benefits to the recipients. Computed tomography (CT) and magnetic resonance imaging (MRI) are currently the imaging modalities of choice in the preoperative evaluation of potential donors. This review provides an overview of key surgical considerations in LDLT that the radiologists must be aware of, and imaging findings on CT and MRI that the radiologists must convey to the surgeons when evaluating potential donors for LDLT.

Impact of the activity calculation method used in transarterial radioembolization: a dosimetric comparison between 90Y-SIRSphere and 90Y-TheraSphere therapy

PURPOSE

Transarterial radioembolization is used to treat primary and secondary liver malignancies. Two commercially available drugs are utilized for the purpose. The aim of our study is to compare the radiation dose delivered to the tumor by these drugs.

MATERIALS AND METHODS

This study included 86 patients (M : F - 7.6 : 1, median age=50.5 years), 46 patients were treated by Y-TheraSphere and 42 patients were treated by Y-SIRSphere. Activity administered in Y-TheraSphere and Y-SIRSphere was calculated using a modified partition model and a modified body surface area model, respectively. The radiation dose delivered by two drugs was calculated and compared in our study.

RESULT

Activity administered in Y-TheraSphere was significantly higher than that of Y-SIRSphere. Hence, the radiation dose delivered to the tumor by Y-SIRSphere was significantly lower (58.4%) than that of Y-TheraSphere (P=0.000).

CONCLUSION

As the radiation dose delivered by Y-SIRSphere was lower than Y-TheraSphere, we believe that the formula for Y-SIRSphere activity calculation needs to be modified so that the optimal dose can be delivered to the tumor.

Comparison of MRI- and CT-based semiautomated liver segmentation: a validation study

PURPOSE

To compare the repeatability, agreement, and efficiency of MRI- and CT-based semiautomated liver segmentation for the assessment of total and subsegmental liver volume.

METHODS

This retrospective study was conducted in 31 subjects who underwent contemporaneous liver MRI and CT. Total and subsegmental liver volumes were segmented from contrast-enhanced 3D gradient-recalled echo MRI sequences and CT images. Semiautomated segmentation was based on variational interpolation and Laplacian mesh optimization. All segmentations were repeated after 2 weeks. Manual segmentation of CT images using an active contour tool was used as the reference standard. Repeatability and agreement of the methods were evaluated with intra-class correlation coefficients (ICC) and Bland-Altman analysis. Total interaction time was recorded.

RESULTS

Intra-reader ICC were ≥0.987 for MRI and ≥0.995 for CT. Intra-reader repeatability was 30 ± 217 ml (bias ± 1.96 SD) (95% limits of agreement: -187 to 247 ml) for MRI and -10 ± 143 ml (-153 to 133 ml) for CT. Inter-method ICC between semiautomated and manual volumetry were ≥0.995 for MRI and ≥0.986 for CT. Inter-method segmental ICC varied between 0.584 and 0.865 for MRI and between 0.596 and 0.890 for CT. Inter-method agreement was -14 ± 136 ml (-150 to 122 ml) for MRI and 50 ± 226 ml (-176 to 276 ml) for CT. Inter-method segmental agreement ranged from 10 ± 47 ml (-37 to 57 ml) to 2 ± 214 ml (-212 to 216 ml) for MRI and 9 ± 45 ml (-36 to 54 ml) to -46 ± 183 ml (-229 to 137 ml) for CT. Interaction time (mean ± SD) was significantly shorter for MRI-based semiautomated segmentation (7.2 ± 0.1 min, p < 0.001) and for CT-based semiautomated segmentation (6.5 ± 0.2 min, p < 0.001) than for CT-based manual segmentation (14.5 ± 0.4 min).

CONCLUSION

MRI-based semiautomated segmentation provides similar repeatability and agreement to CT-based segmentation for total liver volume.

FIRST BRAZILIAN CONSENSUS ON MULTIMODAL TREATMENT OF COLORECTAL LIVER METASTASES. MODULE 1: PRE-TREATMENT EVALUATION

Background

: Liver metastases of colorectal cancer are frequent and potentially fatal event in the evolution of patients with these tumors.

Aim

: In this module, was contextualized the clinical situations and parameterized epidemiological data and results of the various treatment modalities established.

Method:

Was realized deep discussion on detecting and staging metastatic colorectal cancer, as well as employment of imaging methods in the evaluation of response to instituted systemic therapy.

Results

: The next step was based on the definition of which patients would have their metastases considered resectable and how to expand the amount of patients elegible for modalities with curative intent.

Conclusion

: Were presented clinical, pathological and molecular prognostic factors, validated to be taken into account in clinical practice.

Simplified technique for 75% and 90% hepatic resection with hemodynamic monitoring in a large white swine model

BACKGROUND

Accurate measuring of the hepatic hemodynamic parameters in humans is inconvenient. Swine has been a favorite surgical model for the study of liver conditions due to many similarities with human livers. However, pigs cannot tolerate pedicle clamping and to reduce bleeding during resection a simplified technique is required. The aim of this study is to present a simplified technique for different percentages of hepatic resection in a porcine model.

METHODS

Twenty-two consecutive large white pigs were operated with 75% and 90% liver resection. Computarized tomography liver volumetry is performed before and after surgery. In both types of surgery, hemodynamic monitoring was performed using a specialized apparatus.

RESULTS

Resections were performed in both groups successfully. The residual volume in the planned 75% was 235 ± 77 mL and 118 ± 119 mL in the planned 90% resection. For 75% resection, the portal flow was reduced after resection by 8.13 ± 28%, which might be part of systemic circulatory depression. However, the portal pressure increased by 20.1 ± 51%. The hepatic artery flow decreased by 63.86 ± 26.3% as well as the pressure by 5 ± 28%. The central venous pressure at the start of surgery was 3.34 ± 1.9 mm Hg and 2.8 ± 2.2 mm Hg at the end of surgery. The portacaval pressure gradient was 4.4 ± 2.9 mm Hg at the beginning of surgery and was 5.9 ± 2.8 mm Hg at the end of surgery. For 90% resection, the portal flow decreased by 33.6 ± 12.6% and the pressure increased by 104 ± 58%. The hepatic artery flow decreased by 88 ± 7%, and the pressure decreased by 5 ± 14.8%. The central venous pressure was 3.5 ± 1.7 mm Hg before resection and 3 ± 2.5 mm Hg after resection. The portacaval pressure gradient was 3.8 ± 1.1 mm Hg before resection and 8 ± 3.7 mm Hg after resection. The mean anesthesia time was 6.6 ± 1.05 h and 6.9 ± 0.5 h for 75% and 90% resection, respectively. The mean operative time was 4.6 ± 0.9 h and 5 ± 0.7 h for 75% and 90% resections, respectively. The mean time for hepatectomy was 1.23 ± 0.76 h and 2.4 ± 0.1 h for 75% and 90% resection, respectively. The mean time consumed in the measurements was 2.28 ± 1.4 h and 1.1 ± 0.3 h for 75% and 90% resections, respectively. The mean volume of aspirated fluid and blood in the 75% resection was 1062 ± 512 mL, while it was 1050 ± 354 mL in 90% resections.

CONCLUSIONS

The hereby described technique is simple and easily applicable for major liver resection in a porcine model. Portal flow decreases after 90% resection more than in 75% due to the relative reduction of remnant hepatic mass. There was a larger increase in portal pressure following 90% compared to 75% resection. The hepatic artery flow decreases more in 90% than in 75% resections.

Obesogenic diets have deleterious effects on fat deposits irrespective of the nature of dietary carbohydrates in a Yucatan minipig model

The effects of digestible carbohydrates, fructose in particular, on the development of metabolic disturbances remain controversial. We explored the effects of prolonged consumption of high-fat diets differing in their carbohydrate source on fat deposits in the adult Yucatan minipig. Eighteen minipigs underwent computed tomographic imaging and blood sampling before and after 8 weeks of three isocaloric high-fat diets with different carbohydrate sources (20% by weight for starch in the control diet, glucose or fructose, n=6 per diet). Body adiposity, liver volume, and fat content were estimated from computed tomographic images (n=18). Liver volume and lipid content were also measured post mortem (n=12). We hypothesized that the quantity and the spatial distribution of fat deposits in the adipose tissue or in the liver would be altered by the nature of the carbohydrate present in the obesogenic diet. After 8 weeks of dietary exposure, body weight (from 26±4 to 58±3 kg), total body adiposity (from 38±1 to 47±1%; P<.0001), liver volume (from 1156±31 to 1486±66 mL; P<.0001), plasma insulin (from 10±1 to 14±2 mIU/L; P=.001), triacylglycerol (from 318±37 to 466±33 mg/L; P=.005), and free-fatty acids (from 196±60 to 396±59 μmol/L; P=.0001) increased irrespective of the carbohydrate type. Similarly, the carbohydrate type did not induce changes in the spatial repartition of the adipose tissue. Divergent results were obtained for fat deposits in the liver depending on the investigation method. In conclusion, obesogenic diets alter adipose tissue fat deposits and the metabolic profile independently of the nature of dietary carbohydrates.

Automatic labeling of portal and hepatic veins from MR images prior to liver transplantation

PURPOSE

Living donated liver transplantation is an important task since a person (healthy donor) donates some part of her/his liver to a person in this surgery operation. The success of this operation mainly depends on the sufficiency of vessels and volume of the liver. Accurate labeling of portal and hepatic veins of donors reduces the incidence of complications during and after transplantation. Therefore, prior to the hepatic surgery, automatic analysis and labeling of vasculature structures in the liver are vital to see whether liver is suitable or not for transplantation. However, automatic labeling of veins in the liver is challenging because of partial volume effects, noise and image resolution, which causes wrong connections between vessels. The goal of this paper is to propose an automatic labeling approach for vessels.

METHODS

The proposed automated labeling method is based on gray-level values in the MR images and anatomical information. In this work, detection and segmentation of vascular structures in the liver is performed automatically with clustering-based segmentation and refinement stages.

RESULTS

The accuracy of the automatic labeling approach is 85 %. Required processing time for the proposed method (average 6 s) is shorter than manual approach (average 295 s) for labeling of hepatic and portal veins from segmented vessels.

CONCLUSION

The proposed approach is efficient in terms of both computational cost and accuracy of labeling and segmentation of hepatic and portal veins.

Beyond Preconditioning: Postconditioning as an Alternative Technique in the Prevention of Liver Ischemia-Reperfusion Injury

Liver ischemia/reperfusion injury may significantly compromise hepatic postoperative function. Various hepatoprotective methods have been improvised, aiming at attenuating IR injury. With ischemic preconditioning (IPC), the liver is conditioned with a brief ischemic period followed by reperfusion, prior to sustained ischemia. Ischemic postconditioning (IPostC), consisting of intermittent sequential interruptions of blood flow in the early phase of reperfusion, seems to be a more feasible alternative than IPC, since the onset of reperfusion is more predictable. Regarding the potential mechanisms involved, it has been postulated that the slow intermittent oxygenation through controlled reperfusion decreases the burst production of oxygen free radicals, increases antioxidant activity, suppresses neutrophil accumulation, and modulates the apoptotic cascade. Additionally, favorable effects on mitochondrial ultrastructure and function, and upregulation of the cytoprotective properties of nitric oxide, leading to preservation of sinusoidal structure and maintenance of blood flow through the hepatic circulation could also underlie the protection afforded by postconditioning. Clinical studies are required to show whether biochemical and histological improvements afforded by the reperfusion/reocclusion cycles of postconditioning during early reperfusion can be translated to a substantial clinical benefit in liver resection and transplantation settings or to highlight more aspects of its molecular mechanisms.

Delayed diagnosis of alpha-1-antitrypsin deficiency following post-hepatectomy liver failure: A case report

Post-hepatectomy liver failure (PHLF) is a leading cause of morbidity and mortality following major liver resection. The development of PHLF is dependent on the volume of the remaining liver tissue and hepatocyte function. Without effective pre-operative assessment, patients with undiagnosed liver disease could be at increased risk of PHLF. We report a case of a 60-year-old male patient with PHLF secondary to undiagnosed alpha-1-antitrypsin deficiency (AATD) following major liver resection. He initially presented with acute large bowel obstruction secondary to a colorectal adenocarcinoma, which had metastasized to the liver. There was no significant past medical history apart from mild chronic obstructive pulmonary disease. After colonic surgery and liver directed neo-adjuvant chemotherapy, he underwent a laparoscopic partially extended right hepatectomy and radio-frequency ablation. Post-operatively he developed PHLF. The cause of PHLF remained unknown, prompting re-analysis of the histology, which showed evidence of AATD. He subsequently developed progressive liver dysfunction, portal hypertension, and eventually an extensive parastomal bleed, which led to his death; this was ultimately due to a combination of AATD and chemotherapy. This case highlights that formal testing for AATD in all patients with a known history of chronic obstructive pulmonary disease, heavy smoking, or strong family history could help prevent the development of PHLF in patients undergoing major liver resection.

Serial volumetric assessment of large for size liver grafts after whole cadaveric liver transplant in adults: do large liver grafts shrink in size?

BACKGROUND

After whole graft orthotopic liver transplantation (OLT), adaptation of the large grafts' volume to recipient weight is widely accepted despite the paucity of evidence on this subject.

METHODS

Thirty nine patients with GRWR > 2.5% were included in this study and subsequently divided into two groups with 3 ≥ GRWR > 3%. Patients had CT scans at three predetermined time points after OLT used for measuring the liver volume. The objective of this study is to evaluate the volumetric changes of whole large liver grafts after adult OLT.

RESULTS

At LT, the mean graft recipient body weight ratio (GRWR) was 3.1 ± 0.4%. The mean liver weight was 1881 ± 68 g at LT, 2014 ± 99 ml at one week, 1725 ± 126 ml at 3 months, and 1632 ± 117 (ml) at >6 months. There is an initial increase at 1 week after LT and a subsequent decrease of liver volume on later measurements. None of the late volume measurements were significantly different from the initial graft volume at liver transplant in pair wise comparisons ANOVA repeated measures (p > 0.05). Similarly, the mean GRWR did not change significantly between the initial calculation at transplantation date and the subsequent measurements during the different study time points (F = 0.04, p = 0.96) with a mean of 3.1% (95% CI = 2.2-4.2). AUC ROC discriminated a cutoff of 3% for the initial GRWR above which grafts tend to decrease in size over time (c statistics = 0.74, p = 0.036). In a Clustered ANOVA repeated measures, there was no significant difference in the changes of liver volume between both groups. However, patients with GRWR > 3 showed a trend towards a latent reduction in volume over the tracing period. There was a tendency, but none significant; towards a higher bilirubin, AST, ALT levels over the first postoperative days in recipients with GRWR > 3.

CONCLUSION

Large grafts do not significantly decrease in size. Nonetheless, grafts weighing >3% of the GRWR show a different trend towards decrease in size over time.

Preliminary study on liver function changes after trisectionectomy with versus without prior portal vein embolization

PURPOSE

Post-hepatectomy liver failure (PHLF) is the major risk factor for mortality after hepatectomy. Preoperative planning of the future liver remnant volume reduces PHLF rates; however, future liver remnant function (FLR-F) might have an even stronger predictive value. In this preliminary study, we used a new method to calculate FLR-F by the LiMAx test and computer tomography-assisted volumetric-analysis to visualize liver function changes after portal vein embolization (PVE) before extended hepatectomy.

METHODS

The subjects included patients undergoing extended right hepatectomy either directly (NO-PVE group) or after PVE (PVE group). Computed tomography (CT) scan and liver function tests (LiMAx) were done before PVE and preoperatively. FLR-F was calculated and correlated with the postoperative liver function.

RESULTS

There were 12 patients in the NO-PVE group and 19 patients in the PVE group. FLR-F and postoperative liver function correlated significantly in both groups (p = 0.036, p = 0.011), although postoperative liver function was slightly overestimated, at 32 and 45 µg/kg/min, in the NO-PVE and PVE groups, respectively. LiMAx value did not change after PVE.

CONCLUSIONS

Volume-function analysis using LiMAx and CT scan enables us to reliably predict early postoperative liver function. Global enzymatic liver function measured by the LiMAx test did not change after PVE, confirming that liver function distribution in the liver stays constant after PVE. An overestimation of FLR-F is needed to compensate for the intraoperative liver injury that occurs in patients undergoing extended hepatectomy.

Associated Liver Partition and Portal Vein Ligation (ALPPS) vs Selective Portal Vein Ligation (PVL) for Staged Hepatectomy in a Rat Model. Similar Regenerative Response?

Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a two-stage hepatectomy technique which can be associated with a hypertrophic stimulus on the future liver remnant (FLR) stronger than other techniques–such as portal vein ligation (PVL). However, the reason of such hypertrophy is still unclear, but it is suggested that liver transection combined with portal vein ligation (ALPPS) during the first stage of this technique may play a key role. The aim of this study is to compare the hypertrophic stimulus on the FLR and the clinical changes associated with both ALPPS and PVL in a rat surgical model. For this purpose, three groups of SD rats were used, namely ALPPS (n = 30), PVL (n = 30) and sham-treated (n = 30). The second stage of ALPPS (hepatectomy of the atrophic lobes), was performed at day 8. Blood and FLR samples were collected at 1, 24, 48 hours, 8 days and 12 weeks after the surgeries. ALPPS provoked a greater degree of hypertrophy of the FLR than the PVL at 48 hours and 8 days (p<0.05). The molecular pattern was also different, with the highest expression of IL-1β at 24h, IL-6 at 8 days, and HGF and TNF-α at 48 hours and 8 days (p<0.05). ALPPS also brought about a mild proliferative stimulus at 12 weeks, with a higher expression of HGF and TGF-β (p<0.05) than PVL. Clinically, ALPPS caused a significant liver damage during the first 48 hours, with a recovery of liver function at day 8. In conclusion, ALPPS seems to induce higher functional hypertrophy on the FLR than PVL at day 8. Such regenerative response seems to be leaded by a complex interaction between pro-mitogenic (IL-6, HGF, TNF-α) and antiproliferative (IL1-β and TGF-β) cytokines.

[Preoperative imaging/operation planning for liver surgery]

The currently established standard for planning liver surgery is multistage contrast media-enhanced multidetector computed tomography (CM-CT), which as a rule enables an appropriate resection planning, e.g. a precise identification and localization of primary and secondary liver tumors as well as the anatomical relation to extrahepatic and/or intrahepatic vascular and biliary structures. Furthermore, CM-CT enables the measurement of tumor volume, total liver volume and residual liver volume after resection. Under the condition of normal liver function a residual liver volume of 25 % is nowadays considered sufficient and safe. Recent studies in patients with liver metastases of colorectal cancer showed a clear staging advantage of contrast media-enhanced magnetic resonance imaging (CM-MRI) versus CM-CT. In addition, most recent data showed that the use of liver-specific MRI contrast media further increases the sensitivity and specificity of detection of liver metastases. This imaging technology seems to lead closer to the ideal "one stop shopping" diagnostic tool in preoperative planning of liver resection.

Intraoperative simulation of remnant liver function during anatomic liver resection with indocyanine green clearance (LiMON) measurements

OBJECTIVE

Post-hepatectomy liver failure (PHLF) is the major cause of death following liver resection. The aim of this study was to evaluate the feasibility of an intraoperative simulation of post-resection liver function.

METHODS

Intraoperative liver function was measured by indocyanine green (ICG) clearance using the LiMON technology. In 20 patients undergoing anatomic liver resection, ICG plasma disappearance rate (PDR (%/min) and ICG retention at 15 min (R15 ) (%) were measured immediately after the induction of anaesthesia (t0 ), after selective arterial and portovenous inflow trial clamping (TC) of the resected liver segments (t1 ), after the completion of resection (t2 ) and before the closure of the abdominal cavity (t3 ).

RESULTS

The median baseline (t0 ) PDR was 16.5%/min. Trial clamping of the inflow (t1 ) resulted in a significant reduction in PDR to 10.5%/min. Results under TC were similar to those obtained after resection (t2 ) (median PDR: 10.5%/min). Linear regression modelling showed that post-resection liver volume could be accurately predicted by TC of liver inflow (P < 0.0001), but not by determining the resected liver volume. Simulated post-resection liver function under TC correlated well with PHLF and length of hospital stay.

CONCLUSIONS

Intraoperative ICG clearance measurements allow real-time monitoring of intraoperative liver function during surgery. Trial clamping of arterial and portovenous inflow accurately predicts immediate post-resection liver function. The intraoperative measurement of liver function and simulation of post-resection liver function may help to avoid PHLF.

Portal vein embolization with plug/coils improves hepatectomy outcome

BACKGROUND

Portal vein embolization (PVE) has become the standard of care before extended hepatectomy. Various PVE methods using different embolization materials have been described. In this study, we compared PVE with polyvinyl alcohol particles alone (PVA only) versus PVA with plug or coils (PVA + plug/coils).

MATERIALS AND METHODS

Patients undergoing PVE before hepatectomy were included. PVA alone was used until December 2013, thereafter plug or coils were placed in addition. The volume of left lateral liver lobe (LLL), clinical parameters, and liver function tests were measured before PVE and resection.

RESULTS

A total of 43 patients were recruited into the PVA only group and 42 were recruited into the PVA + plug/coils group. There were no major differences between groups except significantly higher total bilirubin level before PVE in the PVA only group, which improved before hepatectomy. Mean LLL volume increased by 25.7% after PVE in the PVA only group and by 44% in the PVA + plug/coils group (P < 0.001). Recanalization was significantly less common in the PVA + plug/coils group. In multivariate regression, initial LLL volume and use of plug or coils were the only parameters influencing LLL volume increase. The postoperative liver failure rate was significantly reduced in PVA + plug/coils group (P = <0.001).

CONCLUSIONS

PVE using PVA particles together with plug or coils is a safe and efficient method to increase future liver remnant volume. The additional central embolization with plug or coils led to an increased hypertrophy, due to lower recanalization rates, and subsequently decreased incidence of postoperative liver failure. No additional procedure-specific complications were observed in this series.

Longitudinal in-vivo volumetry study for porcine liver regeneration from CT data

The use of hepatic-like cloned cord lining epithelial cells (CLEC) to enhance liver regeneration has been proposed, but has not been properly investigated in a large animal study. The paper presents a system developed for the longitudinal in-vivo volumetry study on porcine liver regeneration from computed tomography (CT) data. In this system, a rough 3D liver volume is firstly automatically segmented by a 3D mesh deformation-based method. Then a refinement step to eliminate the segmentation error is carried out by a 3D post-editing tool, followed by mesh-volume conversion and volume calculation. This system was applied in a pilot study, which was composed of 4/4 pigs in the Experimental/Control Groups, to measure liver volumes over pre- to post-operative time course. Experimental results suggest that (1) the developed system can perform CT-based porcine liver volumetry efficiently, and (2) the infusion of CLEC to liver remnant may potentially enhance the liver regeneration.

Function and volume recovery after partial hepatectomy: influence of preoperative liver function, residual liver volume, and obesity

BACKGROUND

The regenerative capacity of the liver is an essential pre-condition for the successful application of partial hepatectomy. However, the actual kinetics of functional recovery remains unspecified and no adequate tool for its clinical monitoring has yet been available.

METHODS

Eighty-five patients receiving major hepatectomy were investigated from the preoperative evaluation until 12 weeks after surgery. Liver function was determined by the LiMAx test for the enzymatic capacity of cytochrome P450 1A2. Liver volume was determined by volumetric analysis of repeated computer tomography scans. Functional and volume recovery were compared during follow-up.

RESULTS

Major hepatectomy decreased liver function capacity to 35.7 ± 13.8% of preoperative function. It was shown that functional recovery already reaches 77.2 ± 33.5% of preoperative values within 10 days. The actual kinetics were dependent from the type and extent of hepatectomy. Complete functional restoration was achieved within 12 weeks, while liver volume still remained at 73.2 ± 14.8% of preoperative. A constant but interindividually variable correlation between function and volume was observed at all points in time.

CONCLUSION

Partial hepatectomy leads to fast and complete functional recovery, while volume recovery is delayed and remains often incomplete. The functional recovery is mainly influenced by the preoperative liver function, the residual liver volume, and by obesity.

Quantitative histological assessment of hepatic ischemia-reperfusion injuries following ischemic pre- and post-conditioning in the rat liver

BACKGROUND

Ischemic preconditioning (IPC) has been shown to protect the liver against ischemia-reperfusion (I/R) injuries. However, ischemic post-conditioning has received little attention. The aim of the present study was to quantify and compare the hepato-protective properties of IPC and IPO, for the first time, using unbiased design-based stereological methods.

METHODS

We divided 67 rats into four groups: sham, liver ischemia (LI), IPC, and IPO. Rats were subjected to 60 min LI, followed by 4- or 24-h reperfusion. We performed quantification of (NVR) and apoptotic cell profile number.

RESULTS

We observed no significant differences in NVR between ischemic groups after 4 h. After 24-h reperfusion, NVR had increased to 70% in the LI group, compared with 51% (P = 0.02) and 49% (P = 0.01) in the IPC and IPO groups, respectively. After 4-h reperfusion, the apoptotic cell number was significantly higher in all ischemic groups than in the sham group; we detected no difference between ischemic groups. After 24-h reperfusion, we detected a significantly lower number of apoptotic cell profiles in the IPC group than in the LI group (P = 0.02). The mean number of apoptotic cell profiles decreased insignificantly in the IPO group (P = 0.06). Liver parameters were at all time comparable between groups.

CONCLUSIONS

After I/R, IPC and IPO reduce the degree of hepatocellular injury. Both methods are equally efficient at preventing hepatocellular necrosis. Furthermore, apoptosis is significantly lower after IPC.