Significance of liver size in hepatic surgery

Liver shape analysis using statistical parametric maps at population scale

BACKGROUND

Morphometric image analysis enables the quantification of differences in the shape and size of organs between individuals.

METHODS

Here we have applied morphometric methods to the study of the liver by constructing surface meshes from liver segmentations from abdominal MRI images in 33,434 participants in the UK Biobank. Based on these three dimensional mesh vertices, we evaluated local shape variations and modelled their association with anthropometric, phenotypic and clinical conditions, including liver disease and type-2 diabetes.

RESULTS

We found that age, body mass index, hepatic fat and iron content, as well as, health traits were significantly associated with regional liver shape and size. Interaction models in groups with specific clinical conditions showed that the presence of type-2 diabetes accelerates age-related changes in the liver, while presence of liver fat further increased shape variations in both type-2 diabetes and liver disease.

CONCLUSIONS

The results suggest that this novel approach may greatly benefit studies aiming at better categorisation of pathologies associated with acute and chronic clinical conditions.

Loss of liver function in chronic liver disease: An identity crisis

Adult hepatocyte identity is constructed throughout embryonic development and fine-tuned after birth. A multinodular network of transcription factors, along with pre-mRNA splicing regulators, define the transcriptome, which encodes the proteins needed to perform the complex metabolic and secretory functions of the mature liver. Transient hepatocellular dedifferentiation can occur as part of the regenerative mechanisms triggered in response to acute liver injury. However, persistent downregulation of key identity genes is now accepted as a strong determinant of organ dysfunction in chronic liver disease, a major global health burden. Therefore, the identification of core transcription factors and splicing regulators that preserve hepatocellular phenotype, and a thorough understanding of how these networks become disrupted in diseased hepatocytes, is of high clinical relevance. In this context, we review the key players in liver differentiation and discuss in detail critical factors, such as HNF4α, whose impairment mediates the breakdown of liver function. Moreover, we present compelling experimental evidence demonstrating that restoration of core transcription factor expression in a chronically injured liver can reset hepatocellular identity, improve function and ameliorate structural abnormalities. The possibility of correcting the phenotype of severely damaged and malfunctional livers may reveal new therapeutic opportunities for individuals with cirrhosis and advanced liver disease.

Strategies to increase the resectability of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is best treated by liver transplantation, but the applicability of transplantation is greatly limited. Tumor resection in partial hepatectomy is hence resorted to. However, in most parts of the world, only 20%-30% of HCCs are resectable. The main reason for such a low resectability is a future liver remnant too small to be sufficient for the patient. To allow more HCC patients to undergo curative hepatectomy, a variety of ways have been developed to increase the resectability of HCC, mainly ways to increase the future liver remnants in patients through hypertrophy. They include portal vein embolization, sequential transarterial chemoembolization and portal vein embolization, staged hepatectomy, two-staged hepatectomy with portal vein ligation, and Associating Liver Partition and Portal Vein Ligation in Staged Hepatectomy. Herein we review, describe and evaluate these different ways, ways that can be life-saving.

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.

Liver volume in the cirrhotic patient: does size matter?

BACKGROUND

While it is established that cirrhosis results in a decrease in liver volume (LV), whether LV itself predicts patient survival is unknown. We hypothesize that estimated LV is an important prognostic indicator in patients with cirrhosis.

METHODS

Data was gathered retrospectively from consecutive patients evaluated for a liver transplant from January 2001 to June 2006. Of 500 patients identified, 323 patients met both inclusion and exclusion criteria. LV per ideal body weight (IBW) was used to correct for body size, and LV/IBW was stratified by median split for survival analyses. Patients were classified into one of three clinical groups: hepatocellular disease (n = 229), cholestatic disease (n = 56), and miscellaneous (n = 38). One of three possible clinical outcomes (survival, liver transplantation, or death) was recorded during the 5-year follow-up, the latter two grouped together as "transplant/death."

RESULTS

Transplant/death occurred in 283 (88 %) subjects. Overall, there was a significant increase in transplant/death in those with lower LV/IBW (χ(2) = 5.27, p = 0.022). When considering the subset with hepatocellular disease, lower LV/IBW was a robust predictor of transplant/death (χ(2) = 9.62, p = 0.002). In multivariate analyses, the LV/IBW trended toward predicting transplant/death (ExpB = 0.943, p = 0.053) independent of Model for End stage Liver Disease (MELD) (ExpB = 1.13, p = 0.001).

DISCUSSION

LV has important predictive value in patients with cirrhosis from hepatocellular disease. This observation appears to be independent of MELD, suggesting LV may impart important prognostic information that is not captured by the MELD score alone. Thus, LV may serve as an important adjunct to the MELD score in patients with hepatocellular disease.

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.

Functional liver reserve parameters predictive for posthepatectomy complications

BACKGROUND

Posthepatectomy complications have markedly decreased with advances in techniques and management; however, surgical risk to patients with injured livers is still not negligible. We evaluated several preoperative parameters of functional liver reserve tests in patients with various liver diseases as predictors of posthepatectomy complications. A comprehensive evaluation of preoperative liver functions is necessary for the prediction of the risk of posthepatectomy complications.

METHODS

Over a 10-y period, we examined 442 patients who underwent hepatectomy for liver and biliary diseases. The patients' background liver diseases included chronic viral liver diseases in 211 patients, obstructive jaundice in 29 patients, and normal liver in 202 patients. Hepatectomy-related postoperative complications (i.e., long-term ascites, intra-abdominal infection, and hepatic failure) occurred in 115 (26%) patients. A multivariate logistic analysis was performed to detect the predictive parameters, and a multivariate linear regression analysis was performed to derive a predictive formula for complications.

RESULTS

A univariate analysis identified 15 significant parameters associated with hepatectomy-related complications, and eight parameters (i.e., presence of chronic hepatic injury, clearance index by technetium-99 m galactosyl human serum albumin liver scintigraphy of ≥ 0.60, total bilirubin level of >1 mg/dL, serum hyaluronic acid level of ≥ 75 ng/mL, major hepatectomy, blood loss of ≥ 950 mL, operating time of ≥ 500 min, and combined resection of another organ or major vessel) were independent predictive factors identified in the multivariate analysis. Clearance index by technetium-99 m galactosyl human serum albumin liver, bilirubin level, hyaluronic acid level, and major hepatectomy were the parameters included in the predictive formula.

CONCLUSIONS

In the present study, we present a comprehensive formula based on the predictive parameters for hepatic complications for prospective assessment to avoid posthepatectomy morbidity.

Liver tissue sparing resection using a novel planning tool

PURPOSE

Accurate preoperative prediction of liver function, volume, and vessel anatomy is essential in preventing postoperative liver failure, optimizing safety, and ensuring optimal outcome in patients undergoing hepatic surgery. We propose that preoperative resection planning provides useful anatomical and volumetric data, allowing for sparing of liver tissue in surgical resections. The purpose of the present study was to evaluate the use of a novel resection planning tool.

METHODS

Thirteen patients undergoing hemihepatectomy were included. Preoperative resection planning was performed using the commercially available software Mint Liver. During resection planning, virtual resections were calculated based on Couinaud classification, Cantlie's line (standard), and individually by the operating surgeon (individual). Intraoperatively, volume and weight of the resected specimen were measured. A 14-day follow-up was conducted, and laboratory parameters were collected. Statistical analysis was performed, comparing virtual resection volumes (i.e., standard vs. individual) and secondarily virtual vs. actual resection volume.

RESULTS

We found a significant difference (p = 0.001) in the comparison of standard vs. individual in all 13 cases, with an average 92.8 mL smaller resected volume, sparing 11.3% of liver parenchyma with virtual resection. No patients suffered from acute liver failure. Perioperative mortality was 0%.

CONCLUSION

Mint Liver is capable of acquiring exact anatomical and volumetric knowledge prior to hepatic resections. Liver parenchyma can be spared by preoperative assessment of the resection plan. We propose that this tool could be an important addition to preoperative patient evaluation, especially in complex liver surgery and living donor liver transplantation where precise volumetry is the decisive factor.

Exact CT-based liver volume calculation including nonmetabolic liver tissue in three-dimensional liver reconstruction

Exact preoperative determination of the liver volume is of great importance prior to hepatobiliary surgery, especially in living donated liver transplantation (LDLT) and extended hepatic resections. Modern surgery-planning systems estimate these volumes from segmented image data. In an experimental porcine study, our aim was (1) to analyze and compare three volume measurement algorithms to predict total liver volume, and (2) to determine vessel tree volumes equivalent to nonmetabolic liver tissue. Twelve porcine livers were examined using a standardized three-phase computed tomography (CT) scan and liver volume was calculated computer-assisted with the three different algorithms. After hepatectomy, livers were weighed and their vascular system plasticized followed by CT scan, CT reconstruction and re-evaluation of total liver and vessel volumes with the three different algorithms. Blood volume determined by the plasticized model was at least 1.89 times higher than calculated by multislice CT scans (9.7% versus 21.36%, P=0.028). Analysis of 3D-CT-volumetry showed good correlation between the actual and the calculated liver volume in all tested algorithms with a high significant difference in estimating the liver volume between Heymsfield versus Heidelberg (P=0.0005) and literature versus Heidelberg (P=0.0060). The Heidelberg algorithm reduced the measuring error with deviations of only 1.2%. The present results suggest a safe and highly predictable use of 3D-volumetry in liver surgery for evaluating liver volumes. With a precise algorithm, the volume of remaining liver or single segments can be evaluated exactly and potential operative risks can therefore be better calculated. To our knowledge, this study implies for the first time a blood pool, which corresponds to nonmetabolic liver tissue, of more than 20% of the whole liver volume.

Extending the frontiers of resectability in advanced colorectal cancer

AIM

To review the advances in the past decade that have enabled more patients with colorectal liver metastases (CRLM) to undergo curative hepatic resection.

METHODS

A comprehensive literature review and pertinent data published on advanced CRLM from The University of Texas M. D. Anderson Cancer Center were used for this review.

RESULTS

Criteria for resectability of CRLM have expanded with the advent of effective chemotherapy, improved surgical technique, and novel strategies such as preoperative volumetry, portal vein embolization, and two-stage hepatectomy. Despite the aggressiveness of these approaches to treating patients with advanced disease, recent series show an improvement in 5-year survival rate for patients with CRLM.

CONCLUSIONS

Advances in multidisciplinary management and careful patient selection have enabled more patients to undergo curative resection for CRLM, with corresponding improvement in survival rates.

Predicting pleural effusion and ascites following extended hepatectomy in the non-cirrhotic liver

BACKGROUND

There are cases in which intractable pleural effusion and/or ascites appear even in the non-cirrhotic liver following extended liver resection, making postoperative management difficult. In this study we investigated the risk factors for pleural effusion and ascites following extended hepatectomy.

METHODS

Subjects were 50 patients between 1996 and 2003 who had hepatic metastasis of colorectal cancer, and who underwent extended liver resection of hemihepatectomy or greater at a time separate from the surgery for their colorectal cancer. The 50 patients were classified according to the presence or absence of pleural effusion and/or ascites, and compared for preoperative ICGR15, pre- and postoperative total serum protein and albumin levels, operating time, amount of blood loss, resected liver weight g/bodyweight kg (Hx ratio), intraoperative fluid replacement volume, period of surgery, operative procedure, use of serum and plasma derivatives, and use of catecholamines.

RESULTS

In a univariate analysis of pleural effusion and ascites, the Hx ratio, period of surgery, operative procedure, use of fresh frozen plasma and use of albumin preparations were significant factors, but in a multivariate analysis only the Hx ratio was a significant independent factor. Among patients with an Hx ratio of 8 or above, many had postoperative pleural effusion and ascites.

CONCLUSIONS

The Hx ratio is a simple method for the evaluation of postoperative remnant liver function and is extremely useful as a predictive factor for pleural effusion and ascites following extended hepatectomy in the non-cirrhotic liver.

Navigator-echo-based MR provides high-resolution images and precise volumetry of swine livers without breath holding or injection of contrast media

The accurate calculation of hepatic volume by computed tomography (CT) or magnetic resonance (MR) is complicated by the need for breath holding and the injection of contrast media. These are often contraindicated in patients with liver failure, and we examined the ability of unenhanced 3-dimensional (3-D) navigator-echo-based MR (NE-MR) to accurately image livers and measure volumes without breath holding compared to unenhanced (plain) or gadolinium-diethylene triamine pentaacetic acid enhanced MR (Gd-MR) in miniature swine (n = 8). Without breath holding, diaphragm movement monitoring with NE-MR reduced motion artifacts in hepatic images compared with the other modalities. Without the injection of contrast media, the signal-to-noise ratios of the images obtained using NE-MR were significantly higher than those from plain MR; Gd-MR was superior to NE-MR, however (79.5 +/- 7.5 vs. 63.2 +/- 6.0 or 97.8 +/- 8.1, respectively; P < 0.01 for each). Overall, NE-MR produced improved high-resolution liver images. Consequently, liver volumes calculated based on NE-MR images were more highly correlated with actual liver weights compared to plain or Gd-MR in the whole livers (n = 8; r = 0.937 vs. 0.835 or 0.904, respectively). Also, NE-MR demonstrated significantly strong correlation between actual weights and volumetry-calculated volumes in regenerative livers 7 days after massive hepatectomy (n = 10, r = 0.989, P < 0.01). In conclusion, our results indicate that without breath holding or the injection of contrast media, 3-D NE-MR can provide both high-resolution liver images and precise hepatic volumes in patients with liver failure due to liver surgery (massive hepatectomy and living donor liver transplantation) or fulminant hepatic failure.

The value of residual liver volume as a predictor of hepatic dysfunction and infection after major liver resection

BACKGROUND AND AIMS

Major liver resection incurs a risk of postoperative liver dysfunction and infection and there is a lack of objective evidence relating residual liver volume to these complications.

PATIENTS AND METHODS

Liver volumetry was performed on computer models derived from computed tomography (CT) angioportograms of 104 patients with normal synthetic liver function scheduled for liver resection. Relative residual liver volume (%RLV) was calculated as the relation of residual to total functional liver volume and related to postoperative hepatic dysfunction and infection. Receiver operator characteristic curve analysis was undertaken to determine the critical %RLV predicting severe hepatic dysfunction and infection. Univariate analysis and multivariate logistic regression analysis were performed to delineate perioperative predictors of severe hepatic dysfunction and infection.

RESULTS

The incidence of severe hepatic dysfunction and infection following liver resection increased significantly with smaller %RLV. A critical %RLV of 26.6% was identified as associated with severe hepatic dysfunction (p<0.0001). Additionally, body mass index (BMI), operating time, and intraoperative blood loss were significant prognostic indicators for severe hepatic dysfunction. It was not possible to predict the individual risk of postoperative infection precisely by %RLV. However, in patients undergoing major liver resection, infection was significantly more common in those who developed postoperative severe hepatic dysfunction compared with those who did not (p=0.030).

CONCLUSIONS

The likelihood of severe hepatic dysfunction following liver resection can be predicted by a small %RLV and a high BMI whereas postoperative infection is more related to liver dysfunction than precise residual liver volume. Understanding the relationship between liver volume and synthetic and immune function is the key to improving the safety of major liver resection.

Nitric oxide and TGF-beta1 inhibit HNF-4alpha function in HEPG2 cells

This study analyzes if the profibrogenic factors nitric oxide and transforming growth factor-beta1 (TGF-beta1) affect hepatocyte nuclear factor-4alpha (HNF-4alpha) function. For this purpose, HepG2 cells were treated with TGF-beta1 or with a nitric oxide donor to determine mRNA levels of coagulation factor VII and HNF-4alpha. Treatment effect on factor VII gene promoter was assessed by chloramphenicol acetyl-transferase assays in cells transfected with the pFVII-CAT plasmid. HNF-4alpha binding and protein levels were determined by gel shift assays and Western blot. TGF-beta1 and nitric oxide downregulated factor VII mRNA levels by inhibiting its gene promoter activity. This inhibition is caused by a decrease in the DNA binding of HNF-4alpha. TGF-beta1 induces degradation of HNF-4alpha in the proteasome while nitric oxide provokes nitrosylation of cysteine residues in this factor. TGF-beta1 and nitric oxide inhibit HNF-4alpha activity. These findings may explain the loss of liver functions that occurs during fibrosis progression.

Expression of Wilms' tumor suppressor in the liver with cirrhosis: relation to hepatocyte nuclear factor 4 and hepatocellular function

The Wilms' tumor suppressor WT1 is a transcriptional regulator present in the fetal but not in the mature liver. Its expression and functional role in liver diseases remains unexplored. In this study, we analyzed WT1 expression by reverse-transcription polymerase chain reaction (RT-PCR) and by immunohistochemistry in normal and diseased livers. In addition, we performed in vitro studies in isolated rat hepatocytes to investigate WT1 regulation and function. We detected WT1 messenger RNA (mRNA) in 18% of normal livers, 17% of chronic hepatitis with minimal fibrosis, 49% of chronic hepatitis with bridging fibrosis, and 71% of cirrhotic livers. In cirrhosis, WT1 immunoreactivity was localized to the nucleus of hepatocytes. WT1 mRNA abundance correlated inversely with prothrombin time (P =.04) and directly with serum bilirubin (P =.002) and with the MELD score (P =.001) of disease severity. In rats, WT1 expression was present in fetal hepatocytes and in the cirrhotic liver but not in normal hepatic tissue. In vitro studies showed that isolated primary hepatocytes express WT1 when stimulated with transforming growth factor beta (TGF-beta) or when the cells undergo dedifferentiation in culture. Moreover, we found that WT1 down-regulates hepatocyte nuclear factor 4 (HNF-4), a factor that is essential to maintain liver function and metabolic regulation in the mature organ. Hepatic expression of HNF-4 was impaired in advanced human cirrhosis and negatively correlated with WT1 mRNA levels (P =.001). In conclusion, we show that WT1 is induced by TGF-beta and down-regulates HNF-4 in liver cells. WT1 is reexpressed in the cirrhotic liver in relation to disease progression and may play a role in the development of hepatic insufficiency in cirrhosis.

[Semi-automatic measurements of hepatic lobes. Application to study of liver volumes. Analysis of 50 computed tomography of normal liver]

OBJECTIVE

Healthy and pathological hepatic volumetry can be of great interest in Liver pathology and treatment. We studied the hepatic segmentation in order to verify if it is possible to estimate the volume of one lobe, when the volume of the other lobe or the total liver is known.

PATIENTS AND METHODS

We studied 50 normal hepatic angiotomographies. For each exam and using the Couinaud classification, we measured the total hepatic volume, the right lobe, the left lobe and the caudate lobe volumes. We used a software called "Hepato" developed in order to quantify automatically CTScan images of the liver. We performed a linear regression analysis (least squares method) and calculated the determination coefficient to study the correlation between the different volumes.

RESULTS

The mean total hepatic volume was 1497 cm3. We obtained for the right lobe 1231 cm3, 226 cm3 for left lobe, and 39 cm3 for the caudate lobe. Moreover there was a weak correlation between these volumes.

CONCLUSION

Exact volume estimation of an hepatic lobe in one patient can not be obtained from the total hepatic volume. However, theses volumes can only be measured from three-dimensional images. Since classical image editing tools are time request, it becomes impossible to utilize them in a clinical routine to get the different volumes of the Liver. Thus, a software dedicated for liver parenchyma recognition is necessary.

Extended hepatic resection for hepatocellular carcinoma in patients with cirrhosis: is it justified?

OBJECTIVE

To evaluate the perioperative outcomes and long-term survival of extended hepatic resection for hepatocellular carcinoma (HCC) in patients with cirrhosis.

SUMMARY BACKGROUND DATA

Hepatic resection is a well-established treatment for HCC in cirrhotic patients with preserved liver function and limited disease. However, the role of extended hepatic resection (more than four segments) for HCC in cirrhotic patients has not been elucidated.

METHODS

Between 1993 and 2000, 45 consecutive patients with histologically confirmed cirrhosis underwent right or left extended hepatectomy for HCC (group A). Perioperative outcomes and long-term survival of these patients were compared with 161 patients with HCC and cirrhosis who underwent hepatic resection of a lesser extent in the same period (group B). All clinicopathologic and follow-up data were collected prospectively.

RESULTS

Group A patients had significantly higher intraoperative blood loss, longer operation time, and longer hospital stay than group B. However, the two groups were similar in overall morbidity and hospital mortality. There were no significant differences in the incidence of liver failure or other complications. The resection margin width was similar between the two groups. Despite significantly larger tumor size in group A compared with group B, long-term survival was comparable between the two groups.

CONCLUSIONS

Extended hepatic resection for HCC can be performed in selected cirrhotic patients with acceptable morbidity, mortality, and long-term survival that are comparable to those of lesser hepatic resection. Extended hepatectomy for large HCC extending from one lobe to the other or central HCC critically related to the hepatic veins is justifiable in cirrhotic patients with preserved liver function and adequate liver remnant.

Extended hepatic resection for hepatocellular carcinoma in patients with cirrhosis: is it justified?

OBJECTIVE

To evaluate the perioperative outcomes and long-term survival of extended hepatic resection for hepatocellular carcinoma (HCC) in patients with cirrhosis.

SUMMARY BACKGROUND DATA

Hepatic resection is a well-established treatment for HCC in cirrhotic patients with preserved liver function and limited disease. However, the role of extended hepatic resection (more than four segments) for HCC in cirrhotic patients has not been elucidated.

METHODS

Between 1993 and 2000, 45 consecutive patients with histologically confirmed cirrhosis underwent right or left extended hepatectomy for HCC (group A). Perioperative outcomes and long-term survival of these patients were compared with 161 patients with HCC and cirrhosis who underwent hepatic resection of a lesser extent in the same period (group B). All clinicopathologic and follow-up data were collected prospectively.

RESULTS

Group A patients had significantly higher intraoperative blood loss, longer operation time, and longer hospital stay than group B. However, the two groups were similar in overall morbidity and hospital mortality. There were no significant differences in the incidence of liver failure or other complications. The resection margin width was similar between the two groups. Despite significantly larger tumor size in group A compared with group B, long-term survival was comparable between the two groups.

CONCLUSIONS

Extended hepatic resection for HCC can be performed in selected cirrhotic patients with acceptable morbidity, mortality, and long-term survival that are comparable to those of lesser hepatic resection. Extended hepatectomy for large HCC extending from one lobe to the other or central HCC critically related to the hepatic veins is justifiable in cirrhotic patients with preserved liver function and adequate liver remnant.

Portal vein embolization vs. portal vein ligation for induction of hypertrophy of the future liver remnant

The objective of this study was to assess the efficacy of right portal vein embolization (PVE) vs. right portal vein ligation (PVL) for induction of hypertrophy of the left lateral liver lobe before extended right hepatectomy. Thirty-four patients with primary or secondary liver tumors and estimated remnant functional liver parenchyma of less than 0.5% of body weight underwent either right PVE (transcutaneous, n = 10; transileocolic, n = 7) or right PVL (n = 17). Liver volume was assessed by CT scan before occlusion of the right portal vein and prior to resection. There were no deaths. The morbidity rate in each group was 5.8% (PVE, 1 abscess; PVL, 1 bile leak). The increase in liver volume was significantly higher after PVE compared with PVL (188 +/- 81 ml vs. 123 +/- 58 ml) (P = 0.012). Postoperative hospital stay was significantly shorter after PVE in comparison to PVL (4 +/- 2.9 days vs. 8.1 +/- 5.1 days; P < 0.01). Curative liver resection was performed in 10 of 17 patients after PVE and 11 of 17 patients after PVL. PVE and PVL were found to be feasible and safe methods of increasing the remnant functional liver volume and achieving resectability for extended liver tumors. PVE results in a significantly more efficient increase in liver volume and a shorter hospital stay.

Virtual hepatic resection using three-dimensional reconstruction of helical computed tomography angioportograms

OBJECTIVE

To establish the accuracy of virtual hepatic resection using three-dimensional (3D) models constructed from computed tomography angioportography (CTAP) images in determining the liver volume (LV) resected during resectional liver surgery.

SUMMARY BACKGROUND DATA

The ability to measure LV before surgery could be useful in determining the extent and nature of hepatic resection. Accurate assessment of LV and an estimate of liver function may also allow prediction of postoperative liver failure in patients undergoing resection, assist in volume-enhancing embolization procedures, help with the planning of staged hepatic resection for bilobar disease, and aid in selection of living-related liver donors.

METHODS

A retrospective study was conducted involving 27 patients scheduled for liver resection. Using mapping technology, 3D models were constructed from helical CTAP images. From these 3D models, tumor volume, total LV, and functional LV were calculated and were compared with body weight. The 3D liver models were subjected to a virtual hepatectomy along established anatomical planes, and the resected LV was calculated. The resected volume predicted by radiologists (unaware of the actual weight) was compared with the specimen weight measured after actual surgical resection.

RESULTS

A significant correlation was found between body weight and functional LV but not total LV. The computer prediction of resected LV after virtual hepatectomy of 3D models compared well with resected liver weight.

CONCLUSION

Virtual hepatectomy of 3D CTAP reconstructed images provides an accurate prediction of liver mass removed during subsequent hepatic resection. The authors intend to combine this technology with an assessment of liver function to attempt to predict patients at risk for liver failure after hepatic resection.