The significance of measuring liver volume using computed tomographic images before and after hepatectomy

Single center experience with ALPPS and timing with stage 2 in patients with fibrotic/cirrhotic liver

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a novel procedure for major resection in patients with insufficient future liver remnant (FLR). Effective FLR augmentation is pivotal in the completion of ALPPS. Liver fibrosis/cirrhosis associated with chronic viral hepatitis impairs liver regeneration. To investigate the augmentation of FLR in associating ALPPS between patients with fibrotic/cirrhotic livers (FL) and non-fibrotic livers (NFL) and compare their short-term clinical outcomes and long-term survival. Patients were divided into two groups based on the Ishak modified staging: non-fibrotic liver group (NFL, stage 0) and fibrotic/cirrhotic liver group (FL, stage 1-5/6). Weekly liver regeneration in FLR, perioperative data, and survival outcomes were investigated. Twenty-seven patients with liver tumors underwent ALPPS (NFL, n = 7; FL, n = 20). NFL and FL patients had viral hepatitis (28.6% [n = 2] and 95% [n = 19]), absolute FLR volume increments of 134.90 ml and 161.85 ml (p = 0.825), and rates of hypertrophy were 16.46 ml/day and 13.66 ml/day (p = 0.507), respectively. In the FL group, baseline FLR volume was 360.13 ml, postoperatively it increased to a plateau (542.30 ml) in week 2 and declined (378.45 ml) in week 3. One patient (3.7%) with cirrhotic liver (stage 6) failed to proceed to ALPPS-II. The overall ALPPS-related major complication rate was 7.4%. ALPPS is feasible for fibrotic liver patients classified by Ishak modified stages ≤ 5. After ALPPS-I, 14 days for FLR augmentation seems an appropriate waiting time to reach a maximum FLR volume in these patients.

Optimal timing of portal vein embolization (PVE) after preoperative biliary drainage for hilar cholangiocarcinoma

BACKGROUND

Preoperative biliary drainage (PBD) followed by portal vein embolization (PVE) has increased the chance of resection for hilar cholangiocarcinoma (CCC). We aim to identify the optimal timing of PVE after PBD in patients undergoing hepatectomy for hilar CCC.

METHODS

We retrospectively reviewed 64 patients who underwent hepatectomy after PBD and PVE for hilar CCC. The patients were classified into 3 groups: Group 1 (PBD-PVE interval ≤7 days), Group2 (8-14 days) and Group 3 (>14 days). The primary end points were 90 days mortality and grade B/C posthepatectomy liver failure (PHLF).

RESULTS

There was no significant difference in primary end points between three groups. A marginally significant difference was found in the incidence of Clavien-Dindo grade ≥3 complications and wound infection (57.1% vs 38.1% vs 72.4%, p = 0.053 and 21.4% vs 38.1% vs 55.2%, p = 0.099). In multivariable analysis, Bismuth type IIIb or IV was independent risk factors for grade B/C PHLF (HR: 4.782, 95% CI 1.365-16.759, p = 0.014).

CONCLUSIONS

Considering that the PBD-PVE interval did not affect PHLF, and the surgical complications increased as the interval increases, PVE as early as possible after PBD would be beneficial.

Prediction of Liver Weight Recovery by an Integrated Metabolomics and Machine Learning Approach After 2/3 Partial Hepatectomy

Liver has an ability to regenerate itself in mammals, whereas the mechanism has not been fully explained. Here we used a GC/MS-based metabolomic method to profile the dynamic endogenous metabolic change in the serum of C57BL/6J mice at different times after 2/3 partial hepatectomy (PHx), and nine machine learning methods including Least Absolute Shrinkage and Selection Operator Regression (LASSO), Partial Least Squares Regression (PLS), Principal Components Regression (PCR), k-Nearest Neighbors (KNN), Support Vector Machines (SVM), Random Forest (RF), eXtreme Gradient Boosting (xgbDART), Neural Network (NNET) and Bayesian Regularized Neural Network (BRNN) were used for regression between the liver index and metabolomic data at different stages of liver regeneration. We found a tree-based random forest method that had the minimum average Mean Absolute Error (MAE), Root Mean Squared Error (RMSE) and the maximum R square (R²) and is time-saving. Furthermore, variable of importance in the project (VIP) analysis of RF method was performed and metabolites with VIP ranked top 20 were selected as the most critical metabolites contributing to the model. Ornithine, phenylalanine, 2-hydroxybutyric acid, lysine, etc. were chosen as the most important metabolites which had strong correlations with the liver index. Further pathway analysis found Arginine biosynthesis, Pantothenate and CoA biosynthesis, Galactose metabolism, Valine, leucine and isoleucine degradation were the most influenced pathways. In summary, several amino acid metabolic pathways and glucose metabolism pathway were dynamically changed during liver regeneration. The RF method showed advantages for predicting the liver index after PHx over other machine learning methods used and a metabolic clock containing four metabolites is established to predict the liver index during liver regeneration.

Deep Learning Algorithm for Automated Segmentation and Volume Measurement of the Liver and Spleen Using Portal Venous Phase Computed Tomography Images

Objective

Measurement of the liver and spleen volumes has clinical implications. Although computed tomography (CT) volumetry is considered to be the most reliable noninvasive method for liver and spleen volume measurement, it has limited application in clinical practice due to its time-consuming segmentation process. We aimed to develop and validate a deep learning algorithm (DLA) for fully automated liver and spleen segmentation using portal venous phase CT images in various liver conditions.

Materials and Methods

A DLA for liver and spleen segmentation was trained using a development dataset of portal venous CT images from 813 patients. Performance of the DLA was evaluated in two separate test datasets: dataset-1 which included 150 CT examinations in patients with various liver conditions (i.e., healthy liver, fatty liver, chronic liver disease, cirrhosis, and post-hepatectomy) and dataset-2 which included 50 pairs of CT examinations performed at ours and other institutions. The performance of the DLA was evaluated using the dice similarity score (DSS) for segmentation and Bland-Altman 95% limits of agreement (LOA) for measurement of the volumetric indices, which was compared with that of ground truth manual segmentation.

Results

In test dataset-1, the DLA achieved a mean DSS of 0.973 and 0.974 for liver and spleen segmentation, respectively, with no significant difference in DSS across different liver conditions (p = 0.60 and 0.26 for the liver and spleen, respectively). For the measurement of volumetric indices, the Bland-Altman 95% LOA was −0.17 ± 3.07% for liver volume and −0.56 ± 3.78% for spleen volume. In test dataset-2, DLA performance using CT images obtained at outside institutions and our institution was comparable for liver (DSS, 0.982 vs. 0.983; p = 0.28) and spleen (DSS, 0.969 vs. 0.968; p = 0.41) segmentation.

Conclusion

The DLA enabled highly accurate segmentation and volume measurement of the liver and spleen using portal venous phase CT images of patients with various liver conditions.

Associated liver partition and portal vein ligation for staged hepatectomy: a review

Outcomes of liver resection have improved with advances in surgical techniques, improvements in critical care and expansion of resectability criteria. However, morbidity and mortality following liver resection continue to plague surgeons. Post-hepatectomy liver failure (PHLF) due to inadequate future liver remnant (FLR) is an important cause of morbidity and mortality following liver resection. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a novel two-staged procedure described in 2012, which aims to induce rapid hypertrophy of the FLR unlike conventional two-stage hepatectomy, which require a longer time for FLR hypertrophy. Careful patient selection and modifications in surgical technique has improved morbidity and mortality rates in ALPPS. Colorectal liver metastases (CRLM) confers the best outcomes post-ALPPS. Patients <60 years old and low-grade fibrosis with underlying hepatocellular carcinoma (HCC) are also eligible for ALPPS. Evidence for other types of cancers is less promising. Current studies, though limited, demonstrate that ALPPS has comparable oncological outcomes with conventional two-stage hepatectomy. Modifications such as partial-ALPPS and mini-ALPPS have shown improved morbidity and mortality compared to classic ALPPS. ALPPS may be superior to conventional two-stage hepatectomy in carefully selected groups of patients and has a promising outlook in liver surgery.

Assessment and optimization of liver volume before major hepatic resection: Current guidelines and a narrative review

Post hepatectomy liver failure (PHLF) remains a significant cause of morbidity and mortality after major liver resection. Although the etiology of PHLF is multifactorial, an inadequate functional liver remnant (FLR) is felt to be the most important modifiable predictor of PHLF. Pre-operative evaluation of FLR function and volume is of paramount importance before proceeding with any major liver resection. Patients with inadequate or borderline FLR volume must be considered for volume optimization strategies such as portal vein embolization (PVE), two stage hepatectomy with portal vein ligation (PVL), Yttrium-90 radioembolization, and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). This paper provides an overview of assessing FLR volume and function, and discusses indications and outcomes of commonly used volume optimization strategies.

Clinical Significance of Spleen-Remnant Liver Volume Ratio in Hepatocellular Carcinoma Surgery

The objective of this study was to explore the value of spleen-remnant liver volume ratio for hepatocellular carcinoma surgery and liver reserve assessment. Spleen-remnant liver volume ratio postoperation was measured with imageological methods and water displacement, and the liver function postoperation and hospital stay of patients with different spleen-remnant liver volume ratios were compared. Spleen-remnant liver volume ratio was closely related to liver function assessment postoperation. The higher the ratio, the higher the assessment score of liver function postoperation would be. When spleen-remnant liver volume ratio was ≤0.9, the patients had a fast recovery and short hospital stay. Spleen-remnant liver volume ratio can effectively predict the recovery and liver reserve of patients with hepatocellular carcinoma postoperation. When postoperative spleen-remnant liver volume ratio is predicted to be ≤0.9, the operation can be performed; and when the ratio is predicted to be ≥1.2, the operation is not suggested.

Impact of non-alcoholic fatty liver disease on liver volume in humans

AIM

Knowledge of liver volume is needed in the preoperative screening of liver transplant donors and in pharmacokinetic studies. In previous studies, bodyweight, surface area, age and sex have been identified as predictors of total liver volume, but the impact of non-alcoholic fatty liver disease (NAFLD) independent of body size on liver volume has not been determined. We examined whether and to what extent liver fat due to NAFLD influences liver volume.

METHODS

We quantified the percentage of liver fat by proton magnetic resonance spectroscopy ((1) H-MRS) and liver total, lean and fat volumes using magnetic resonance imaging (MRI) in 112 subjects (62 women, 50 men), who were characterized with respect to metabolic parameters associated with NAFLD.

RESULTS

Of the subjects, 45% had NAFLD (liver fat 12.5 ± 4.5% vs 1.8 ± 1.6%, NAFLD vs no NAFLD, P < 0.001). Total liver volume was 29% higher in subjects with NAFLD (1.91 ± 0.45 L) than in those with no NAFLD (1.49 ± 0.31 L, P < 0.001). In multiple linear regression analysis, the percentage of liver fat and bodyweight independently explained variation in total liver volume (r(2)  = 0.42, P < 0.001). The r-values for the relationship between metabolic parameters and the total liver fat volume were not significantly better than those between metabolic parameters and the percentage of liver fat.

CONCLUSION

Both bodyweight and NAFLD increase liver volume independent of each other. Measurement of liver fat by (1) H-MRS allows accurate quantification of NAFLD and calculation of total liver volume.

Preoperative assessment of postoperative liver function: the importance of residual liver volume

An inadequate volume of future liver remnant (FLR) remains an absolute contraindication to liver resection. FLR measurement correlates with surgical outcome and is fundamental to identify those patients that may benefit from portal vein embolization (PVE) and to assess the liver volume change following embolization. In order to minimize the risk of postoperative liver failure, preoperative analysis of FLR must be included in the surgical planning of every major liver resection. The aims of this review are to describe the use of preoperative volumetric analysis in modern liver surgery and indications for PVE.

Is computed tomography volumetric assessment of the liver reliable in patients with cirrhosis?

OBJECTIVES

The estimation of liver volume (LV) has been widely studied in normal liver, the density of which is considered to be equivalent to 1 kg/l. In cirrhosis, volumetric evaluation and its correlation to liver mass remain unclear. The aim of this study was to evaluate the accuracy of computed tomography (CT) scanning to assess LV in patients with cirrhosis.

METHODS

Liver volume was evaluated by CT (CTLV) and correlated to the explanted liver weight (LW) in 49 patients. Liver density (LD) and its association with clinical features were analysed. Commonly used formulae for estimating LV were also evaluated. The real density of cirrhotic liver was prospectively measured in explant specimens.

RESULTS

Wide variations between CTLV (in ml) and LW (in g) were found (range: 3-748). Cirrhotic livers in patients with hepatitis B virus infection presented significantly increased LD (P = 0.001) with lower CTLV (P = 0.005). Liver volume as measured by CT was also decreased in patients with Model for End-stage Liver Disease scores of >15 (P = 0.023). Formulae estimating LV correlated poorly with CTLV and LW. The density of cirrhotic liver measured prospectively in 15 patients was 1.1 kg/l.

CONCLUSIONS

In cirrhotic liver, LV assessed by CT did not correspond to real LW. Liver density changed according to the aetiology and severity of liver disease. Commonly used formulae did not accurately assess LV.

Comparison of remnant to total functional liver volume ratio and remnant to standard liver volume ratio as a predictor of postoperative liver function after liver resection

BACKGROUNDS/AIMS

The future liver remnant (FLR) is usually calculated as a ratio of the remnant liver volume (RLV) to the total functional liver volume (RLV/TFLV). In liver transplantation, it is generally accepted that the ratio of the graft volume to standard liver volume (SLV) needs to be at least 30% to 40% to fit the hepatic metabolic demands of the recipient. The aim of this study was to compare RLV/TFLV versus RLV/SLV as a predictor of postoperative liver function and liver failure.

METHODS

CT volumetric measurements of RLV were obtained retrospectively in 74 patients who underwent right hemihepatectomy for a malignant tumor from January 2010 to May 2013. RLV and TFLV were obtained using CT volumetry, and SLV was calculated using Yu's formula: SLV (ml)=21.585×body weight (kg)(0.732)×height (cm)(0.225). The RLV/SLV ratio was compared with the RLV/TFLV as a predictor of postoperative hepatic function.

RESULTS

Postheptectomy liver failure (PHLF), morbidity, and serum total bilirubin level at postoperative day 5 (POD 5) were increased significantly in the group with the RLV/SLV ≤30% compared with the group with the RLV/SLV >30% (p=0.002, p=0.004, and p<0.001, respectively). But RLV/TFLV was not correlated with PHLF and morbidity (p=1.000 and 0.798, respectively). RLV/SLV showed a stronger correlation with serum total bilirubin level than RLV/TFLV (RLV/SLV vs. RLV/TFLV, R=0.706 vs. 0.499, R(2)=0.499 vs. 0.239).

CONCLUSIONS

RLV/SLV was more specific than RLV/TFLV in predicting the postoperative course after right hemihepatectomy. To determine the safe limit of hepatic resection, a larger-scaled prospective study is needed.

Usefulness of examining hepatic functional volume using technetium-99m galactosyl serum albumin scintigraphy in hepatocellular carcinoma

OBJECTIVES

The aim of the study was to clarify the clinical significance of single-photon emission computed tomography/computed tomography (SPECT/CT) imaging in terms of technetium-99m galactosyl human serum albumin (99mTc-GSA) scintigraphy. To this end, we examined the relationship using data from surgical records of 67 patients with hepatocellular carcinoma who underwent hepatectomy.

MATERIALS AND METHODS

Liver functional parameters or functional volume was estimated by 99mTc-GSA scintigraphy and computed tomography volumetry was used to estimate morphological volume.

RESULTS

Liver uptake ratio at 15 min (LHL15) was correlated with the indocyanine green retention rate at 15 min (ICGR15; R=-0.608, P<0.01); however, five patients (7.5%) had values outside this correlation. In these patients, LHL15 reflected clinical status and patient outcomes more. Although morphological and functional volumes were well correlated (P<0.01), functional volume was decreased in the diseased liver with portal vein tumor thrombus or portal vein embolization. By applying 99mTc-GSA volumetry, portal pressure and alkaline phosphatase level were correlated with decreased volume of the embolized liver, and platelet count and cholesterol level were correlated with increased volume of the nonembolized liver (P<0.05). By measuring functional volume, four patients who were functionally borderline on the basis of the ICGR15 test safely underwent scheduled major hepatectomy.

CONCLUSION

Under the ICGR15 test as the standard for preoperative hepatic function, auxiliary application of LHL15 and functional volumetry provides useful information on hepatocellular carcinoma patients undergoing hepatectomy.

Correlation between morphological and functional liver volume in each sector using integrated SPECT/CT imaging by computed tomography and technetium-99m galactosyl serum albumin scintigraphy in patients with various diseases who had undergone hepatectomy

OBJECTIVES

The aim of the study was to accurately examine the functional volume (RI-vol) of the hepatic segments on single photon emission computed tomography/computed tomography (CT) fusion imaging by technetium-99m galactosyl human serum albumin scintigraphy and compare it with the RI-vol and morphological volume obtained on computed tomography (CT-vol).

METHODS

In 60 patients with various liver background statuses who had undergone hepatectomy, the RI-vol and CT-vol were examined in each sector using imaging analysis. The values from a control group (n=91) were used as reference data.

RESULTS

The mean RI-vol and CT-vol of the right liver were 64 ± 10 and 63 ± 6%, respectively, whereas the values for the left liver were 36 ± 10 and 37 ± 6%, respectively. Compared with the control group, the ratios in each hemiliver were similar. The mean RI-vol and CT-vol for each sector were also similar, and significant positive correlations were identified between the two volumes (P<0.01). In four patients with hepatic tumors involving the main hepatic vessels or the bile duct and in 10 patients who had undergone portal vein embolization, the actual RI-vol in the injured sector was significantly decreased compared with CT-vol (P<0.05). There were marked changes in functional volume in segment 6+7 and segment 2+3 after portal vein embolization (P<0.05).

CONCLUSION

Volumetric measurement using single photon emission computed tomography/CT imaging with technetium-99m galactosyl human serum albumin scintigraphy is useful for evaluating the functional volume in separated livers and offers a good reflection of the background liver status.

Equivalent outcomes after anatomical and non-anatomical resection of small hepatocellular carcinoma in patients with preserved liver function

BACKGROUND

Although anatomical resection (AR) is considered better than non-anatomical resection (NAR) for the treatment for hepatocellular carcinoma (HCC), there is only limited evidence in support of this argument.

AIM

The aim of this study was to investigate whether AR is superior to NAR regarding postoperative outcomes in patients with small solitary HCC and preserved liver function.

METHODS

The study subjects were 92 curatively-resected patients with adequate liver function reserve (indocyanine green retention rate at 15 min <15%, prothrombin time >70%, serum albumin >3.5 g/dl) and macroscopically small (≤3.0 cm) solitary HCC without macroscopic vascular invasion; 30 patients underwent AR and 62 patients NAR. Postoperative short-term outcomes including mortality and morbidity and long-term outcomes were compared in the two groups.

RESULTS

There was no significant difference in clinicopathological background in the two groups. Although resected liver volume was significantly larger in the AR group than the NAR group (p < 0.0001), no significant differences were detected in the incidence of mortality or morbidity. For long-term outcomes, there were no significant differences between the two groups in disease-free survival or overall survival. Multivariate analysis showed that the extent of surgical procedure was not a significant prognostic factor for disease-free or overall survival.

CONCLUSIONS

AR of a solitary small HCC did not carry postoperative outcome advantages compared with NAR in patients with preserved liver function. We recommend NAR for hepatic resection of small solitary HCC in patients with preserved liver function.

Assessing renal parenchymal volume on unenhanced CT as a marker for predicting renal function in patients with chronic kidney disease

OBJECTIVES

To estimate renal volume in chronic kidney disease (CKD) patients using a semiautomated software and compare them with split renal function estimates from radionuclide renogram (RR). We proposed that renal volume from unenhanced computed tomography (CT) scans may serve as surrogate marker for assessing renal function in CKD patients.

MATERIALS AND METHODS

Unenhanced multidetector CT scans of 26 patients with CKD (estimated glomerular filtration rate [eGFR] <60 mL/kg/body surface area [BSA]) and 10 controls (eGFR >60 mL/kg/BSA) were analyzed to calculate renal volumes using a semiautomated software (AMIRAV5.2.0). Volumes obtained were then correlated with corresponding eGFR and split renal function estimates from RR. Volumes were also compared with those obtained on enhanced scans in 10 cases (five disease group, five controls). Bland-Altman analysis was used to assess agreement between methods.

RESULTS

A moderately positive correlation was found between renal volume obtained on unenhanced CT and eGFR (r = 0.65, P < .0001), whereas a significantly high correlation with split function estimates from RR (r = 0.95, P < .001) was found. Bland-Altman analysis revealed a good agreement between renal volume from CT and renal function from RR (34/36 observations were within 95% CI and there were two outliers). Correlation between volumes obtained from unenhanced and enhanced CT scans was also significant (r = 0.96).

CONCLUSION

In patients with CKD, renal volume derived from unenhanced CT can possibly serve as a surrogate marker for assessing and monitoring renal function reserves to plan further management.

Variation in hepatic segmental volume distribution according to different causes of liver cirrhosis: CT volumetric evaluation

OBJECTIVE

To investigate if there is difference in hepatic segmental volume distribution according to causes of liver cirrhosis (LC) using computed tomography volumetric analysis.

METHODS

On computed tomographic scans, hepatic segmental volumes were measured in 90 patients with LC of 4 different causes (alcohol, hepatitis B virus (HBV), hepatitis C virus (HCV), and cryptogenic cirrhosis). The volumetric indices were compared.

RESULTS

The volume proportion of the lateral segment in the liver in patients with HBV was significantly higher than in the patients with HCV (P = 0.038). Hepatic volume distribution in alcoholic LC showed differences: larger caudate lobe volume than HBV- and HCV-induced LC (P = 0.029 and P = 0.031), larger right lobe volume (P = 0.043) and smaller proportion of the lateral segment in the liver (P = 0.003) than in HBV-induced LC.

CONCLUSIONS

Computed tomography volumetric analysis showed differences in hepatic segmental volume distribution in cirrhotic patients according to causes of LC.

Standardized liver volumetry for portal vein embolization

Major and extended hepatic resections are being performed with increasing frequency as morbidity and mortality rates after major hepatectomies have declined and definitions of resectability have expanded for primary and metastatic hepatic malignancies. Systematic assessment of the anticipated functional remnant liver is essential before major hepatic resection to avoid postoperative hepatic insufficiency and its attendant sequelae. The volume of the future liver remnant (FLR) correlates with FLR function and postoperative outcome. This article describes the rationale for FLR measurement, methods of measuring FLR volume, and standardization to the total estimated liver volume. The indications for portal vein embolization based on standardized liver volumetry are summarized.

Perioperative management of hepatic resection toward zero mortality and morbidity: analysis of 793 consecutive cases in a single institution

BACKGROUND

The mortality rates associated with hepatectomy are still not zero. Our aim was to define the risk factors for complications and to evaluate our perioperative management.

STUDY DESIGN

Between 2001 and 2008, 793 consecutive patients (547 men and 246 women; mean age ± SD, 56.1 ± 14.9 years) underwent hepatectomy without gastrointestinal resection and choledocojejunostomy at our center. Of these patients, 354 (44.6%) were positive for the hepatitis B virus surface antigen and/or the hepatitis C virus antibody. We categorized 783 (98.7%) patients as Child-Pugh class A. Major resection (sectionectomy, hemihepatectomy, and extended hemihepatectomy), was performed in 535 patients (67.5%) and re-resection in 81 patients (10.2%).

RESULTS

The median operative time was 345.5 minutes and median blood loss was 360 mL. The rate of red blood cell transfusion was 6.8%. The morbidity rate was 15.6%. Reoperations were performed in 19 patients (2.4%). The mean postoperative hospital stay was 18.4 ± 10.4 days. The in-hospital mortality rate was 0.1% (1 of 793 patients; caused by hepatic failure). The independent relative risk for morbidity was influenced by an operative time of more than 360 minutes, blood loss of more than 400 mL, and serum albumin levels of less than 3.5 g/dL, as determined using multivariate logistic regression analysis.

CONCLUSIONS

Shorter operative times and reduced blood loss were obtained by improving the surgical technique and using new surgical devices and intraoperative management, including anesthesia. Additionally, decision making using our algorithm and perioperative management according to CDC guidelines reduced the morbidity and mortality associated with hepatectomy.

Clinical application of measurement of liver volume by multi-slice spiral CT

The volume of the liver can not only directly reflect the size of the liver, liver capacity and the quantity of liver cells, but also, to a certain extent, indirectly reflect blood perfusion and metabolic capability of the liver. Therefore, liver volume is an important parameter to evaluate hepatic reserve function. The accurate measurement of liver volume has great significance for the formulation of treatment program, prevention of liver failure, and prediction of prognosis. This article is to review the clinical application of measurement of liver volume by multi-slice spiral CT.

Influence of chemotherapy on liver regeneration induced by portal vein embolization or first hepatectomy of a staged procedure for colorectal liver metastases

BACKGROUND

Although portal vein embolization (PVE) and staged hepatectomy (StHx), as well as prehepatectomy chemotherapy, have improved the resectability rate of patients with multiple bilobar colorectal liver metastases, the impact of prehepatectomy chemotherapy on liver hypertrophy following PVE and/or StHx has remained unclear.

METHODS

Sixty patients who underwent PVE followed by one-stage hepatectomy and StHx with or without PVE were analyzed. Liver hypertrophy following PVE and/or the first hepatectomy of StHx and the clinical course after final hepatectomy was compared between patients with and without prehepatectomy chemotherapy.

RESULTS

No difference of volume of the future liver remnant (FLR) before or after the procedure was seen between the chemotherapy group and the nonchemotherapy group. Even in 38 patients who underwent right PVE prior to a planned right hemihepatectomy, the chemotherapy group (n = 14) and the nonchemotherapy group (n = 24) were comparable in terms of volumes of FLR before (P = 0.71) and after (P = 0.29) PVE and posthepatectomy courses. However, the liver hypertrophy ratio for patients showing steatosis in adjacent nonmalignant liver parenchyma, which frequently is induced by chemotherapy, was lower than that for patients without steatosis (P = 0.04).

CONCLUSIONS

Although prehepatectomy chemotherapy did not impair liver hypertrophy, PVE and/or StHx accompanied by prehepatectomy chemotherapy should be performed with particular care to minimize risk of liver failure after the procedure.

Estimation of standard liver volume for liver transplantation in the Chinese population

INTRODUCTION

The accurate assessment of standard liver volume (SLV) is necessary for the safety of both the donor and the recipient in living donor liver transplantation. However, the accuracy of SLV formulas relates to cohorts or races. This study examined the accuracy of a simple linear formula versus previous formulas of SLV for Chinese adults.

METHODS

Among 112 patients with normal liver, we created a new formula for SLV with stepwise regression analysis using the following variables: age, gender, body weight, body height, body mass index, and body surface area. The agreement between the actual liver volume (LV) and calculated LV using various formulas was prospectively evaluated among 63 living donors by paired-sample student's t-test and Lin's concordance correlation coefficient.

RESULTS

A new formula was developed SLV (mL) = 949.7 x BSA (m(2)) - 48.3 x age - 247.4 where age was counted as 1 for those <40, 2 if 41-60, and 3 if >60 years old. The calculated LV using our formula showed no significant difference from the actual LV using the paired-samples student's t-test (P = .653). Lin's concordance correlation coefficient showed substantial agreement between estimated LV using our formula and actual LV. Furthermore, this study also observed an almost perfect agreement between our formula and the Yoshizumi et al formula.

CONCLUSION

Our formula, which accurately estimated LV among Chinese adults, may be applicable to adults of other ethnicitis.

Usefulness of measuring hepatic functional volume using Technetium-99m galactosyl serum albumin scintigraphy in bile duct carcinoma: report of two cases

We report the usefulness of measuring functional liver volume in two patients undergoing hepatectomy. Case 1 involved a 47-year-old man with hepatitis B virus infection. The indocyanine green test retention rate at 15 min (ICGR15) was 14%. Liver uptake ratio (LHL15) by technetium-99 m galactosyl human serum albumin ((99m)Tc-GSA) liver scintigraphy was 0.91. The patient displayed hilar bile duct carcinoma necessitating right hepatectomy. After preoperative portal vein embolization (PVE), future remnant liver volume became 54% and functional volume by (99m)Tc-GSA became 79%. Although the permitted resected liver volume was lower than the liver volume, scheduled hepatectomy was performed following the results of functional liver volume. Case 2 involved a 75-year-old man with diabetes. ICGR15 was 27.4% and LHL15 was 0.87. The patient displayed bile duct carcinoma located in the upper bile duct with biliary obstruction in the right lateral sector. The right hepatectomy was scheduled. After PVE, future remnant volume became 68% and functional volume became 88%. Although ICGR15 was worse as 31%, planned hepatectomy was performed due to the results of functional volume. In the liver with biliary obstruction or portal embolization, functional liver volume is decreased more than morphological volume. Measurement of functional volume provides useful information for deciding operative indication.

Does adjuvant radiotherapy suppress liver regeneration after partial hepatectomy?

PURPOSE

To analyze the influence of the adjuvant radiotherapy (RT) on the liver regeneration and liver function after partial hepatectomy (PH).

METHODS AND MATERIALS

Thirty-four patients who underwent PH for biliary tract cancer between October 2003 and July 2005 were reviewed. Hemihepatectomy was performed in 14 patients and less extensive surgery in 20. Of the patients, 19 patients had no adjuvant therapy (non-RT group) and 15 underwent adjuvant RT by a three-dimensional conformal technique (RT group). Radiation dose range was 40 to 50 Gy (median, 40 Gy). Liver volume on computed tomography and the results of liver function tests at 1, 4, 12, 24, and 52 weeks after PH were compared between the RT and non-RT groups.

RESULTS

The preoperative characteristics were identical for both groups. During the interval between Weeks 4 and 12 when adjuvant RT was delivered in the RT group, the increase in liver volume was significantly smaller in the RT group than non-RT group (22.9 +/- 38.3cm(3) and 81.5 +/- 75.6cm(3), respectively, p = 0.007). However, the final liver volume measured at 1 year after PH did not differ between the two groups (p = 0.878). Liver function tests were comparable for both groups. The resection extent and original liver volume was independent factors for final liver volume measured at 1 year after PH.

CONCLUSIONS

In this study, adjuvant RT delayed the liver regeneration process after PH, but the volume difference between the two study groups became nonsignificant after 1 year. Adjuvant RT had no additional adverse effect on liver function after PH.

Anatomic versus limited nonanatomic resection for solitary hepatocellular carcinoma

BACKGROUND

Although anatomic liver resection is preferred when treating hepatocellular carcinoma (HCC), evidence that it improves survival when compared with an adequate nonanatomic resection is lacking. The purpose of this study was to compare the survival impact of anatomic versus nonanatomic resection in patients with solitary HCC.

PATIENTS AND METHODS

Clinicopathologic data were available for 125 patients who underwent hepatectomy for a solitary HCC confined to 1 or 2 Couinaud's segments. These patients were divided into 2 groups based on the hepatectomy procedure: anatomic (n = 83) and nonanatomic (n = 42) resection.

RESULTS

No differences were detected either in the hepatic recurrence rates (P = .38) or in the overall survival rates (P = .34) between the anatomic group and the nonanatomic group. The hepatectomy procedure (anatomic vs nonanatomic resection) did not affect survival in either univariate (P = 0.34) or multivariate analysis (relative risk, 1.574; P = .22). The proportion of patients who survived after recurrence was greater in the nonanatomic (15/42) than the anatomic group (13/83; P = .049), and the median survival time after recurrence was greater in patients who underwent nonanatomic resection (991 days; range, 131-4073 days) than in patients with anatomic resection (310 days; range, 48-1887 days; P = .045).

CONCLUSIONS

No superiority was seen in survival when HCC was treated by anatomic resection. Maintaining adequate liver function regardless of whether the resection is anatomic or not may be of greater importance.

Regeneration after two-stage hepatectomy vs. repeat resection for colorectal metastasis recurrence

BACKGROUND

Two-stage hepatectomy aims to minimize liver failure risk by performing a second resection after regeneration, assuming that remnant liver hypertrophy after the second resection is similar to that seen in repeat hepatectomy, yet the impact of a two-stage strategy on liver volume and function remains to be demonstrated.

PATIENTS AND METHODS

Twenty patients undergoing two-stage hepatectomy for multiple colorectal cancer metastases and 21 patients with more than two sections of liver parenchyma totally removed by repeat liver resections for recurrence were enrolled. Liver volumes after final hepatectomy and postoperative liver function were compared.

RESULTS

Median total liver volumes before initial hepatectomy and after final hepatectomy of multiple resections were 942 and 863 ml in patients with repeat hepatectomy, whereas volumes at corresponding time points were 957 and 777 ml in patients with two-stage hepatectomy. The ratio of total liver volume after both hepatectomies to preoperative volume in the two-stage group (81.7%) was lower than that in the repeat resection group (92.0%, P = 0.027). Greater aspartate aminotransferase and prothrombin time and lower platelet count 1 month postoperatively and lower albumin at 6 months were evident after two-stage hepatectomy compared with repeat hepatectomy.

CONCLUSIONS

Two-stage hepatectomy is characterized by diminished hepatic regenerative capacity and postoperative liver function.

Improving outcome in patients undergoing liver surgery

Liver surgery is associated with many factors, which may affect outcome. Preoperative assessment of patient's general condition, resectability, and liver reserve are paramount for success. The Child-Pugh score and other scoring systems only partially enables to assess the risk associated with liver surgery. The presence of portal hypertension per se is a major risk factor for hepatectomy. Intraoperatively, any attempts should be made to minimize blood loss. Low central venous pressure and inflow occlusion best prevent bleeding. Ischemic preconditioning and intermittent clamping are routinely applied in many centers to protect against long periods of ischemia, although the mechanisms of protection remain unclear. In this review we describe recent advances in activated pathways associated with protection against ischemia. Postoperatively, the best factor impacting on outcome probably resides in experienced medical care particularly in the intensive care setting. Currently, no drug or gene therapy approaches has reached the clinic. The future relies on new insight into mechanisms of ischemia-reperfusion injury.

Assessment of future remnant liver regeneration after portal vein embolization using three-dimensional CT and MR volumetric analyses

The purpose of this study is to portray right portal vein embolization (PVE) as a valuable technique that helps in expanding the volume of the left liver lobe and discuss the relevant published work. We describe our experience with four patients who underwent PVE and analyse the value of CT and MRI in the preoperative evaluation of these patients. Four patients with hepatic malignancy (hepatocellular carcinoma) (n=2) and metastatic liver disease (n=2) underwent portal vein occlusion. PVE was carried out in three patients using polyvinyl alcohol and stainless steel coils. Portal vein ligation was carried out in the fourth patient. In patients who were candidates for right hepatectomy, CT volumetric analysis was carried out before the surgery to assess the total liver volume and the future remnant liver, which is the residual left hepatic volume (in cases of right hepatectomy) or left lateral segment volume (in cases of right tri-segmentectomy). Because the left lobe volumes were insufficient, patients were selected to undergo right PVE. Computed tomography volumetry was carried out 2-4 weeks after embolization to assess left hepatic lobe regeneration. Magnetic resonance volumetric analysis was carried out in two patients before and after embolization. All four patients had significant regeneration of the left lobe and tolerated the surgery with uneventful postoperative recovery.

Geometric shifting of the porta hepatis during posthepatectomy radiotherapy for biliary tract cancer

PURPOSE

To evaluate geometric shifting of the porta hepatis induced by liver regeneration during radiotherapy (RT) after partial hepatectomy for biliary tract cancer.

METHODS AND MATERIALS

Between August 2004 and August 2005, the study enrolled 10 biliary tract cancer patients who underwent hemihepatectomy or more extensive surgery and were scheduled to receive postoperative RT. All patients received 4500 cGy RT in 25 fractions with concurrent 5-fluorouracil. Before RT and in the third and fifth weeks during RT, the liver volume was determined using CT, and geometric location of the porta hepatis was determined using a conventional simulator.

RESULTS

The liver volume increase during RT was 246.6 +/- 118.2 cm(3). The overall actual shifting length of the porta hepatis was 9.8 +/- 2.5 mm, with right and left hepatectomy causing a 10.1 +/- 1.7 mm shift to the right or 9.2 +/- 4.3 mm shift to the left, respectively. The actual shifting length of the porta hepatis was proportional to the increase in liver volume during RT (r = 0.742, p = 0.014).

CONCLUSION

The results of this study have demonstrated that the porta hepatis can be shifted by liver regeneration after partial hepatectomy. We recommend an additional RT margin or adaptive RT (repeat planning at several intervals during the treatment course) to avoid exclusion of the porta hepatis from the RT target volume after partial hepatectomy for biliary tract cancer.

Changes in liver volume from birth to adulthood: a meta-analysis

A diversity of equations is available for the estimation of liver volume (LV), derived from studies in populations of ethnically homogeneous individuals and using a variety of methods of measurement. The aim of this study was to integrate all published pediatric data and to define a general equation for estimating LV from birth onward. Data were collated from 5,036 subjects (birth to 18 yr old). Equations were developed based on simple regression against body surface area (BSA) and multiple regression of LV with weight, height, BSA, age, gender, race, methodology, and year of publication as covariates. These equations, together with those reported in the literature, were compared for accuracy of prediction of LV from birth to 18 yr old. The most parsimonious equation to describe LV was selected according to the Akaike information criteria (AIC), precision and bias and following visual inspection of residual errors and observed vs. predicted plots: LV = 0.722 * BSA(1.176). The multiple regression models indicated that Japanese have up to 19% larger livers compared to Caucasians for a given body weight. Radiographic and ultrasonic measurements were associated with up to 8% lower estimates of liver size compared to measurements made at autopsy. There was no evidence that gender or the year in which a study was published (1933-1999) influenced the estimation of LV. The general equation was also applied to predict adult LV, and its precision and accuracy was found to be superior to those of 10/11 published adult models. In conclusion, we have developed a more general model to predict LV in pediatric populations and young adults, and have investigated a range of covariates.

Portal vein embolization in preparation for major hepatic resection: evolution of a new standard of care

Portal vein (PV) embolization (PVE) is gaining acceptance in the preoperative management of patients selected for major hepatic resection. PVE redirects portal blood flow to the intended liver remnant to induce hypertrophy of the nondiseased portion of the liver and thereby reduce complications and shorten hospital stays after resection. This article reviews the rationale and existing literature on PVE, including the mechanisms of liver regeneration, the pathophysiology of PVE, the imaging techniques used to measure liver volumes and estimate functional hepatic reserve, and the technical aspects of PVE, including approaches and embolic agents used. In addition, the indications and contraindications for performing PVE in patients with and without chronic liver disease and the multidisciplinary approach required for the treatment of these complex cases are emphasized.

The influence of spleen size on liver regeneration after major hepatectomy in normal and early cirrhotic liver

BACKGROUND/PURPOSE

The relationship between liver regeneration and spleen size after major hepatectomy in normal and cirrhotic liver was studied by single photon emission computed tomography (SPECT).

MATERIALS AND METHODS

Twenty-six patients, 18 patients with normal liver and eight patients with cirrhotic liver, receiving major hepatectomy were included. Liver and spleen volumes were measured by SPECT before major hepatectomy, 6 months, 1 year and 2 years after operation. The correlation of liver and spleen volume during liver regeneration was analyzed.

RESULTS

In both groups, the residual liver volume increased within the first year and decreased in the second year. No difference in regeneration ability was found. The spleen volume in cirrhotic liver was increased, with a trend similar to normal liver during the first year. In contrast, the increased spleen volume persisted up to the second year in cirrhotic patients. Age per year, the female sex, and body surface index had a positive correlation with increased percentage of liver volume. The spleen volume per 100 ml with time played a significantly negative role in increasing percentage of liver volume, confidence interval: -2.16 to -27.92, P=0.011.

CONCLUSION

In early cirrhotic liver within normal functional limits, the liver still could regenerate as a normal liver after major hepatectomy in 1 year. Age, the female sex, and body surface index had positive correlation but the size of spleen volume played a negative role to regenerative liver volume.

Changes in splenic volume during liver regeneration

Little is known about the relation between liver regeneration and splenic size. We monitored serial changes in liver and spleen volumes using computed tomography in 24 patients with biliary cancer who underwent right hepatectomy or more extensive liver resection following portal vein embolization (PVE). Nonembolized hepatic segments increased in volume from 316 +/- 97 cm3 (34% +/- 8% of total liver volume) before PVE to 410 +/- 115 cm3 (44% +/- 8%) after PVE. The volume of nonembolized hepatic segments (i.e., remnant liver) increased to 617 +/- 111 cm3 (59% +/- 10% of total liver volume before PVE) 14 days after hepatectomy and then increased slowly to reach 795 +/- 231 cm3 (76% +/- 16%) 1 year after hepatectomy. Splenic volume increased from 87 +/- 29 cm3 before PVE to 104 +/- 38 cm3 (119% +/- 17% of original volume) after PVE. Splenic volume increased to 137 +/- 65 cm3 (155% +/- 40%) by 14 days after hepatectomy and to 155 +/- 67 cm3 (179% +/- 41%) by 28 days after hepatectomy, with no further change at 1 year after hepatectomy (153 +/- 92 cm3; 174% +/- 79%). The rate of increase in splenic volume within the first 14 days after hepatectomy was 2.7 +/- 3.6 cm3/day, correlating well with increases in remnant liver volume ( r = 0.64, p = 0.0006). These data indicate that the spleen is enlarged during liver regeneration, suggesting that the liver and spleen share certain common growth regulatory mechanisms.

Portal vein embolization with polyvinyl alcohol particles and coils in preparation for major liver resection for hepatobiliary malignancy: safety and effectiveness--study in 26 patients

PURPOSE

To evaluate whether preoperative portal vein embolization (PVE) with polyvinyl alcohol (PVA) particles and coils is safe and effective for inducing lobar hypertrophy in patients with hepatobiliary malignancy.

MATERIALS AND METHODS

PVE was performed in 26 patients. All patients had malignancy: metastases (n = 11), cholangiocarcinoma (n = 9), hepatocellular carcinoma (n = 5), and gallbladder carcinoma (n = 1). One patient had underlying liver disease caused by hepatitis. PVE was performed if the future liver remnant (FLR) was estimated to be less than 25% of the total liver volume. PVE was performed with a percutaneous transhepatic approach (right, 25 patients; left, one patient). PVA particles and coils were used to occlude the right portal system and veins supplying segment IV to promote FLR hypertrophy (segments I-III +/- IV). FLR hypertrophy was assessed with comparison of computed tomographic scans obtained before and 2-4 weeks after PVE. Effectiveness evaluation was based on changes in absolute FLR size and ratio of FLR to total estimated liver volume (TELV). Safety of PVE and hepatic resection was determined with postprocedure complication rate and median hospital stay.

RESULTS

Sixteen patients underwent hepatic resection (right trisegmentectomy [n = 13], right lobectomy [n = 3]) without mortality. Ten patients did not undergo resection (complete remission after medical therapy [n = 1], lack of regeneration [n = 2], extrahepatic disease undetected prior to PVE [n = 7]). Six patients had biliary obstruction; five were treated percutaneously before PVE. No patient developed postembolization syndrome or signs of fulminant hepatic insufficiency after PVE or resection. Two patients had complications after PVE that did not preclude successful resection. Median hospital stays were 1 day (PVE) and 7 days (liver resection). Mean absolute FLR increased from 325.0 to 458.6 cm3 (increase, 41.1%). Mean TELV was 1,784.8 cm3. FLR/TELV ratio increase was 8%.

CONCLUSION

Preoperative PVE with PVA particles and coils is safe and effective for inducing lobar hypertrophy in patients with advanced hepatobiliary malignancy.

Transhepatic portal vein embolization: anatomy, indications, and technical considerations

Portal vein embolization (PVE) is increasingly being accepted as a useful procedure in the preoperative treatment of patients selected for major hepatic resection. PVE is performed via either the percutaneous transhepatic or the transileocolic route and is usually reserved for patients whose future liver remnants are too small to allow resection. It is a safe and effective method for inducing selective hepatic hypertrophy of the nondiseased portion of the liver and may thereby reduce complications and shorten hospital stays after resection. A thorough knowledge of hepatic segmentation and portal venous anatomy is essential before performing PVE. In addition, the indications and contraindications for PVE, the methods for assessing hepatic lobar hypertrophy, the means of determining optimal timing of resection, and the possible complications of PVE need to be fully understood before undertaking the procedure. Technique may vary among operators, and further research is necessary to determine the best embolic agents available and the expected rates of liver regeneration for PVE. Nevertheless, as hepatobiliary surgeons become more experienced at performing extended hepatic resections, PVE may be requested more frequently.

Body surface area and body weight predict total liver volume in Western adults

Computed tomography (CT) is used increasingly to measure liver volume in patients undergoing evaluation for transplantation or resection. This study is designed to determine a formula predicting total liver volume (TLV) based on body surface area (BSA) or body weight in Western adults. TLV was measured in 292 patients from four Western centers. Liver volumes were calculated from helical computed tomographic scans obtained for conditions unrelated to the hepatobiliary system. BSA was calculated based on height and weight. Each center used a different established method of three-dimensional volume reconstruction. Using regression analysis, measurements were compared, and formulas correlating BSA or body weight to TLV were established. A linear regression formula to estimate TLV based on BSA was obtained: TLV = -794.41 + 1,267.28 x BSA (square meters; r(2) = 0.46; P <.0001). A formula based on patient weight also was derived: TLV = 191.80 + 18.51 x weight (kilograms; r(2) = 0.49; P <.0001). The newly derived TLV formula based on BSA was compared with previously reported formulas. The application of a formula obtained from healthy Japanese individuals underestimated TLV. Two formulas derived from autopsy data for Western populations were similar to the newly derived BSA formula, with a slight overestimation of TLV. In conclusion, hepatic three-dimensional volume reconstruction based on helical CT predicts TLV based on BSA or body weight. The new formulas derived from this correlation should contribute to the estimation of TLV before liver transplantation or major hepatic resection.

Liver regeneration after major hepatectomy for biliary cancer

BACKGROUND

The aim of this study was to evaluate serial changes in liver volume after major hepatectomy for biliary cancer and to elucidate clinical factors influencing liver regeneration.

METHODS

Serial changes in liver volume were determined, using computed tomography, in 81 patients with biliary cancer who underwent right hepatic lobectomy or more extensive liver resection with or without portal vein resection and/or pancreatoduodenectomy. Possible factors influencing liver regeneration were evaluated by univariate and multivariate analyses.

RESULTS

The remnant mean(s.d.) liver volume was 41(8) per cent straight after hepatectomy. This increased rapidly to 59(9) per cent within 2 weeks, then increased more slowly, finally reaching a plateau at 74(12) per cent about 1 year after hepatectomy. The regeneration rate within the first 2 weeks was 16(8) cm3/day and was not related to the extent of posthepatectomy liver dysfunction. On multivariate analysis, the extent of liver resection (P < 0.001), body surface area (P = 0.02), combined portal vein resection (P = 0.024) and preoperative portal vein embolization (P = 0.047) were significantly associated with the liver regeneration rate within the first 2 weeks. In addition, body surface area (P < 0.001) and liver function expressed as plasma clearance rate of indocyanine green (P = 0.01) were significant determinants of final liver volume 1 year after hepatectomy.

CONCLUSION

The liver regenerates rapidly in the first 2 weeks after major hepatectomy for biliary cancer. This early regeneration is influenced by four clinical factors. Thereafter, liver regeneration progresses slowly and stops when the liver is three-quarters of its original volume, approximately 6 months to 1 year after hepatectomy.

Portal vein embolization: rationale, technique and future prospects

BACKGROUND

Advances in surgery have reduced the mortality rate after major liver resection, but complications resulting from inadequate postresection hepatic size and function remain. Portal vein embolization (PVE) was proposed to induce hypertrophy of the anticipated liver remnant in order to reduce such complications. The techniques, measurement methods and indications for this treatment remain controversial.

METHODS

A Medline search was performed to identify papers reporting the use of PVE before hepatic resection. Techniques, complications and results are reviewed.

RESULTS

Complications of PVE typically occur in less than 5 per cent of patients. No specific substance (cyanoacrylate, thrombin, coils or absolute alcohol) emerged as superior. The increase in remnant liver volume averages 12 per cent of the total liver. The morbidity rate of resection after treatment is less than 15 per cent and the mortality rate is 6-7 per cent with cirrhosis and 0-6.5 per cent without cirrhosis. Embolization is currently used for patients with a normal liver when the anticipated liver remnant volume is 25 per cent or less of the total liver volume, and for patients with compromised liver function when the liver remnant volume is 40 per cent or less.

CONCLUSION

This treatment does not increase the risks associated with major liver resection. It may be indicated in selected patients before major resection. Future prospective studies are needed to define more clearly the indications for this evolving technique.

Efficacy and safety of preoperative percutaneous transhepatic portal embolization with absolute ethanol: a clinical study

BACKGROUND

Preoperative portal embolization has been performed by using various thrombogenic substances to increase the safety and resectability of liver surgery. We evaluated the clinical safety and efficacy of using absolute ethanol in preoperative portal embolization.

METHODS

Our study included 19 patients who had undergone right hepatic lobectomy. According to our criteria for right lobectomy of the liver, seven patients were not appropriate for the operation because of a high risk in each of postoperative liver failure. Those patients received preoperative right portal embolization with 11 to 32 ml absolute ethanol. The remaining 12 patients satisfied our criteria and received no preoperative embolization.

RESULTS

Although alanine aminotransferase concentrations increased dramatically after the embolization, all serologic changes reverted within 3 weeks. The mean volume of the nonembolized lobe increased from 320 cm3 to 619 cm3 and 667 cm3 2 and 4 weeks, respectively, after embolization. The mean regeneration rate of this lobe was 21.3 cm3 per day for the first 2 weeks and 11.4 cm3 per day for the first 4 weeks after embolization. All patients underwent right lobectomy of the liver and survived; none of the patients had severe complications associated with embolization or surgery. The postoperative survival periods were not statistically significant between the patients with and without preoperative portal embolization.

CONCLUSIONS

According to our criteria for liver surgery, the seven patients should not have undergone major surgery, but each underwent right lobectomy of the liver and all survived, showing that portal embolization with absolute ethanol brings about compensatory hepatic hypertrophy for major surgery and that its extreme effect on liver regeneration could widen the range of patients appropriate for liver surgery.