Effect of temporary occlusion of the hepatic vein on dual blood in the liver: evaluation with spiral CT

Adverse effects of graft congestion and ameliorative effects of hepatocyte growth factor after liver transplantation in rats

Living donor liver transplantation (LT) and deceased donor split-LT often result in congestion within liver grafts. The regenerative process and function of congested areas, especially graft congestion associated with LT, are not well understood. Therefore, we created new rat models with congested areas in partially resected livers and orthotopically transplanted these livers into syngeneic rats to observe liver regeneration and function in congested areas. This study aimed to compare liver regeneration and the function of congested areas after liver resection and LT, and to explore a new approach to ameliorate the adverse effects of graft congestion. Although the congested areas after liver resection regenerated normally on postoperative day 7, the congested areas after LT had poor regeneration with abscess development on postoperative day 7. Necrotic areas in congested areas were larger after LT than after liver resection on postoperative days 1, 3, and 7 ( p < 0.05, p < 0.05, and p < 0.01, respectively). Although congested areas after liver resection did not affect survival, in the LT model, the survival of rats with congested areas was significantly poorer even with larger grafts than that of rats with smaller noncongested grafts ( p = 0.04). Hepatocyte growth factor administration improved the survival rate of rats with congested grafts from 41.7% to 100%, improved the regeneration of congested areas, and significantly reduced the size of necrotic areas ( p < 0.05). Thus, congested areas in liver grafts may negatively impact recipients. Short-term administration of hepatocyte growth factor may improve postoperative outcomes of recipients with graft congestion and contribute to more effective use of liver grafts (approval number: MedKyo-23137, Institutional Ethics Committee/Kyoto University).

Effects of Adding Congested Segment IV to the Left Lateral Graft on Short-term Outcomes in Pediatric Living-donor Liver-transplant Recipients

Background

In some pediatric patients undergoing living-donor liver transplantation, segment IV without the middle hepatic vein can be added to a left lateral segment graft to obtain larger graft volume. Because no clear consensus on this technique exists, this study investigated the effects of congested areas on postoperative outcomes in pediatric patients with biliary atresia undergoing living-donor liver transplantation.

Methods

We retrospectively reviewed data of recipients with biliary atresia aged ≤15 y who had undergone living-donor liver transplantation at Kyoto University Hospital between 2006 and 2021 and with graft-to-recipient weight ratios (GRWR) of ≤2%. Based on the percentage of congested area in the graft, patients were classified into the noncongestion (n = 40; ≤10%) and congestion (n = 13; >10%) groups. To compare the differences between groups with similar nooncongestive GRWRs and investigate the effect of adding congested areas, patients in the noncongestion group with GRWRs of ≤1.5% were categorized into the small noncongestion group (n = 24).

Results

GRWRs and backgrounds were similar between the noncongestion and congestion groups; however, patients in the congestion group demonstrated significantly longer prothrombin times, higher ascites volumes, and longer hospitalization. Further, compared with the small noncongestion group, the congestion group had significantly greater GRWR and similar noncongestive GRWR; however, the congestion group had significantly longer prothrombin time recovery (P = 0.020, postoperative d 14), higher volume of ascites (P < 0.05, consistently), and longer hospitalization (P = 0.045), requiring significantly higher albumin and gamma-globulin transfusion volumes than the small noncongestion group (P = 0.027 and P = 0.0083, respectively). Reoperation for wound dehiscence was significantly more frequent in the congestion group (P = 0.048).

Conclusions

In pediatric liver-transplant recipients, adding a congested segment IV to the left lateral segment to obtain larger graft volume may negatively impact short-term postoperative outcomes.

Congestion Area of the Right Lobe Graft in Living Donor Liver Transplantation: Quantitative Evaluation of Hemodynamics Using Computed Tomography Perfusion

BACKGROUND

The hemodynamics of congestion areas in the right lobe graft after living donor liver transplantation (LDLT) remains unclear. The aim of this study was to elucidate the hemodynamics of congestion areas in the right lobe graft after LDLT using computed tomography (CT) perfusion imaging and the dual-input maximum slope method.

METHODS

Sixteen recipients underwent CT perfusion of the liver and portal phase abdominal to pelvic CT 1week after LDLT using a right lobe graft. The attenuation of segments V and VIII on the portal venous phase abdominal to the pelvic CT scan was classified into 3 categories: hyperattenuation, iso-attenuation, and hypoattenuation. Mean arterial blood flow (AF, mL/min/100 mL tissue), portal blood flow (PF, mL/min/100 mL tissue), and perfusion index (%) [PI = AF/(AF + PF) × 100] were compared between the hyperattenuation group and iso-attenuation group. The independent t test was used for these statistical analyses.

RESULTS

On the portal phase abdominal scan, 15 segments, 16 segments, and 1 segment showed hyperattenuation, iso-attenuation, and hypoattenuation, respectively. The mean AF and PI of the hyperattenuation group (44.4 ± 24.4, 30.2 ± 13.5) were significantly higher than those of the iso-attenuation group (28.0 ± 7.8, 19.9 ± 6.2) (P < .05, P < .05).

CONCLUSIONS

The congested liver segments showed high AF and high PI on CT perfusion imaging. This method enables the feasible quantification of the hemodynamics and the description of focal hemodynamic change in the graft after LDLT.

Reconstruction of the middle hepatic vein using a vein graft from the resected portion of the liver

Background

The middle hepatic veins are often infiltrated by intrahepatic cholangiocarcinoma. Reconstruction of the hepatic vein plays a critical role in preserving more of the residual liver volume and reducing the risk of postoperative liver failure in extreme hepatectomy. We here report a novel way to reconstruct middle hepatic vein by using vessel grafts from wasted liver.

Case presentation

Case 1: A 64-year-old man was diagnosed with intrahepatic cholangiocarcinoma. The bifurcation and left branch of the portal vein were stenosed, and the root of the middle hepatic vein was infiltrated by the tumor. An extended left hepatectomy was performed, the portal vein was resected and reconstructed, and the middle hepatic vein was reconstructed by anastomosing the proximal left hepatic vein to the distal middle hepatic vein. Case 2: A 69-year-old woman was diagnosed with intrahepatic cholangiocarcinoma. The tumor was located in the left lobe of the liver and the left and middle hepatic veins were infiltrated by the tumor. An extended left hepatectomy was performed, and the left portal vein was used as a vein graft to reconstruct the middle hepatic vein. Both of the two patients’ postoperative ultrasound showed vessel graft patency.

Conclusion

Using a vein graft from the resected portion of the liver to reconstruct the middle hepatic vein was a useful technique and showed good result.

Venous thrombosis and segmental hypoperfusion in amebic liver abscess: MDCT demonstration and its implications

PURPOSE

To report venous thrombosis and associated perfusion defect in amebic liver abscess (ALA) using MDCT.

METHOD

MDCT images of 62 patients with ALA were reviewed for venous thrombosis and associated perfusion abnormalities.

RESULT

The study found 43 (69%) patients with venous thrombosis: portal vein thrombosis (PVT) occurred in 39, hepatic vein thrombosis (HVT) in 37 and inferior vena cava (IVC) thrombosis in 4. Combined PVT and HVT occurred in 33 (77%) patients. The portal vein thrombi remained localized in subsegmental branches in 25 patients and extended to segmental branches in 14. The hepatic vein thrombi were confined to peripheral branches in 18 patients; they progressed to the main trunk in 19 and to the IVC in 4. A wedge-shaped hypoattenuating zone suggesting ischemia was identified in 33 (77%) patients in portal phase: 31 had combined PVT and HVT, 2 had HVT alone, but none had PVT alone. It occurred significantly more often with combined PVT and HVT than HVT alone (p = 0.05). Arterial phase enhancement occurred in 2 of 13 patients with multiphasic CT. All patients were symptomatic despite medical therapy and therefore required percutaneous drainage. About half of the patients were identified with ruptured abscesses. Segmental atrophy was observed in seven of nine patients who underwent follow-up CT.

CONCLUSION

Combined PVT and HVT commonly occur with ALA and often manifests as segmental hypoperfusion in portal venous phase, indicating ischemia. The detection of such events by CT may be indicative of severe disease that requires aggressive management involving percutaneous drainage.

Venous thrombosis and segmental hypoperfusion in amebic liver abscess: MDCT demonstration and its implications

PURPOSE

To report venous thrombosis and associated perfusion defect in amebic liver abscess (ALA) using MDCT.

METHOD

MDCT images of 62 patients with ALA were reviewed for venous thrombosis and associated perfusion abnormalities.

RESULT

The study found 43 (69%) patients with venous thrombosis: portal vein thrombosis (PVT) occurred in 39, hepatic vein thrombosis (HVT) in 37 and inferior vena cava (IVC) thrombosis in 4. Combined PVT and HVT occurred in 33 (77%) patients. The portal vein thrombi remained localized in subsegmental branches in 25 patients and extended to segmental branches in 14. The hepatic vein thrombi were confined to peripheral branches in 18 patients; they progressed to the main trunk in 19 and to the IVC in 4. A wedge-shaped hypoattenuating zone suggesting ischemia was identified in 33 (77%) patients in portal phase: 31 had combined PVT and HVT, 2 had HVT alone, but none had PVT alone. It occurred significantly more often with combined PVT and HVT than HVT alone (p = 0.05). Arterial phase enhancement occurred in 2 of 13 patients with multiphasic CT. All patients were symptomatic despite medical therapy and therefore required percutaneous drainage. About half of the patients were identified with ruptured abscesses. Segmental atrophy was observed in seven of nine patients who underwent follow-up CT.

CONCLUSION

Combined PVT and HVT commonly occur with ALA and often manifests as segmental hypoperfusion in portal venous phase, indicating ischemia. The detection of such events by CT may be indicative of severe disease that requires aggressive management involving percutaneous drainage.

Indicator for local recurrence of hepatocellular carcinoma after proton beam therapy: analysis of attenuation difference between the irradiated tumor and liver parenchyma on contrast enhancement CT

OBJECTIVES

We aimed to identify dynamic CT features that can be used for prediction of local recurrence of hepatocellular carcinoma (HCC) after proton beam therapy (PBT).

METHODS

We retrospectively retrieved CT scans of patients with PBT-treated HCC, taken between January 2004 and December 2016. 17 recurrent lesions and 34 non-recurrent lesions were retrieved. The attenuation difference between irradiated tumor and irradiated parenchyma (AD_HCC-IP) was compared in the two groups by using the Mann-Whitney U test. Cut-off value of AD_HCC-IP was estimated by using the Youden index.

RESULTS

The follow-up time after PBT initiation ranged from 374 to 2402 days (median, 1069 days) in recurrent lesions, and 418 to 2923 days (median, 1091.5 days) in non-recurrent lesions (p = 0.892). The time until appearance of local recurrence after PBT initiation ranged from 189 to 2270 days (median, 497 days). AD_HCC-IP of recurrent lesions [mean, -21.8 Hounsfield units (HU); from -95 to -31 HU] was significantly greater than that of non-recurrent lesions (mean, -51.7 HU; from -117 to -12 HU) at 1-2 years in portal venous phase (p = 0.039). 5-year local tumor control rates were 0.93 and 0.56 in lesions with AD_HCC-IP at 1-2 years in PVP < -55 and ≥ -55 HU, respectively.

CONCLUSION

The attenuation difference between irradiated HCC and irradiated liver parenchyma in portal venous phase at 1-2 years after PBT can predict long-term local recurrence of HCC after treatment.

ADVANCES IN KNOWLEDGE

We identified a cut-off value for contrast enhancement of HCC after PBT that could predict future local recurrence.

CT and MRI imaging and interpretation of hepatic arterioportal shunts

Hepatic arterioportal shunts (HAPS) occur due to organic or functional fistulization of blood flow between arterial hepatic vasculature and venous portal systems. It is a type of hemodynamic abnormality of the liver being observed increasingly with the use of temporal imaging modalities. HAPS occur due to other underlying hepatic abnormalities including the presence of an underlying tumor or malignancy. When a HAPS is present, the appearance of these abnormalities on imaging studies suggests an underlying abnormality, must be considered atypical even if asymptomatic, and warrants careful evaluation. Over time, and as a function of degree of fistulae, symptoms and potential life-threatening complications may arise from the HAPS. These systemic complications may include the development of portal hypertension, splenomegaly, as well as accelerated metastasis in patients with malignant tumors. This manuscript reviews common underlying conditions associated with HAPS and their radiologic interpretation.

Clinical characteristics of hepatic Arterioportal shunts associated with hepatocellular carcinoma

BACKGROUND

Hepatic arterioportal shunt (A-P shunt) is defined as the direct blood flow established between hepatic artery and portal venous system; it is frequently observed in patients with hepatocellular carcinoma (HCC). Clinically, it is important to diagnose HCC associated A-P shunts, as it may impact the treatment strategy of the patients. In the present study, we described the imaging findings of the HCC associated A-P shunts and discussed the treatments strategy of such patients. From the findings, we also discussed the potential cause of A-P shunts.

METHODS

Clinical data of HCC patients (n = 560), admitted to the hospital between April 2012 to April 2014, were reviewed. Hepatic angiography was used to examine the presence of A-P shunts. Of the 137 patients with A-P shunts, grading of the A-P shunts was performed, and statistical analysis of the different grades of A-P shunts and clinical characteristics was performed.

RESULTS

The hepatic angiography confirmed that 99 patients had typical A-P shunts (Grade 1-3), and 38 patients had atypical A-P shunts. Embolization was the main strategy used to treat A-P shunts, in which liquid embolic agents appeared to provide a better treatment outcome. The correlation analysis showed that the grading of portal vein tumor thrombus was significantly associated with the grading of A-P shunt (p = < 0.001, Spearman correlation coefficient was 0.816 ± 0.043).

CONCLUSIONS

We characterized A-P shunts and proposed treatment strategy for treating HCC patients with various levels of A-P shunts. The findings supported the hypothesis that the formation of HCC associated A-P shunts was caused by tumor thrombus.

Influence of outflow-obstructed liver volume and venous communication development: A three-dimensional volume study in living donors

Living donor liver transplantation using the left liver graft with the middle hepatic vein (MHV) is a well-established procedure. Following such procedures, outflow obstruction occurs in remnant livers. However, the effects of the outflow-obstructed liver volume (LV_Out-Ob ), with or without venous communication development, remain unclear. The aim of the study is to investigate effects of outflow-obstructed regions by focusing on short-term outcomes and remnant liver hypertrophy in left liver procurement donors. Of 532 donors, we collected data from 119 undergoing left liver procurement with the MHV. Postoperative hepatic parameters, venous communication development, and liver hypertrophy were evaluated in 2 donor groups based on LV_Out-Ob . The left liver was procured with the MHV in 119 donors, who formed 2 more groups based on the median LV_Out-Ob : large-outflow-obstruction group (n = 60; LV_Out-Ob  ≥ 263 mL) and small-outflow-obstruction (n = 59; LV_Out-Ob  < 263 mL) group. Postoperative liver function parameters were significantly impaired in the large-outflow-obstruction group compared with the small-outflow-obstruction group. Postoperative venous communication developed in 52 (66.7%) of 78 donors analyzed. Hypertrophy ratios in remnant right livers and right paramedian sectors were significantly higher in the small-outflow-obstruction group than in the large-outflow-obstruction group (P = 0.01 and P = 0.02, respectively). The liver hypertrophy ratio of outflow-obstructed regions was better, especially in small regions developing venous communication (P =  0.001). The postoperative morbidity rate did not differ significantly (P = 0.66). In conclusion, the procurement of the left liver graft with the MHV was safely performed with minimal morbidity by assessing the donor remnant right liver volume with and without outflow obstruction. Attention should be paid that postoperative hepatic parameters and remnant liver hypertrophy were impaired in the remnant livers with large outflow-obstructed regions compared with those with small outflow-obstructed regions. Liver Transplantation 23 1531-1540 2017 AASLD.

Partial Hepatectomy with Middle Hepatic Vein Reconstruction Using a Left Inferior Vena Cava Graft

Duplicated inferior vena cava (IVC) is a rare congenital anomaly. We describe the utility of a new graft from the left IVC in a patient with duplicated IVC for reconstructing the middle hepatic vein (MHV) after partial hepatectomy with MHV resection. A 67-year-old woman with hepatitis C was found to have a liver tumor. Magnetic resonance imaging confirmed that the tumor, which was attached to the MHV, was hepatocellular carcinoma. Central bisectionectomy (S4, S5, and S8 resection) could not be tolerated because of poor liver function and a low future liver remnant volume. Therefore, partial hepatectomy with MHV resection was performed. The left IVC was harvested as a venous graft and was substituted for the resected MHV. She recovered uneventfully and was discharged on postoperative day 12. To the best of our knowledge, this is the first report of using the left IVC as a venous graft. The left IVC is a good candidate graft for the MHV or for portal vein reconstruction because of its length, diameter, and easy harvesting (it did not require an extra incision) in a patient with duplicated IVC.

Features of acute liver congestion on gadoxetate disodium-enhanced MRI in a rat model: Role of organic anion-transporting polypeptide 1A1

PURPOSE

To evaluate the features of hepatic congestion on gadoxetate disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and the mechanisms responsible for the radiological findings in a rat model of partial liver congestion.

MATERIALS AND METHODS

A conventional T1 -weighted spin-echo sequence of the liver was performed using a 1.5T magnetic resonance imager with an 80-mm magnetic aperture for animal studies. We induced regional congestion using partial left lateral hepatic vein ligation (n = 5) and evaluated the following in both congestive liver (CL) and noncongestive liver (non-CL): 1) chronological changes in the relative enhancement (RE) up to 60 minutes after Gd-EOB-DTPA administration, and 2) mRNA and protein expression of rat organic anion transporting protein 1a1 (Oatp1a1).

RESULTS

The RE in the CL reached a small peak (18%) at 5 minutes, corresponding to approximately half of the value observed in the non-CL, then slowly decreased in a linear manner thereafter. The degree of RE in the CL was significantly lower than that in the non-CL for up to 30 minutes (P < 0.05). An immunohistological examination showed that Oatp1a1 protein expression was downregulated in the CL. The mRNA level of Oatp1a1 in the CL was significantly upregulated, compared with that in control rat liver (P = 0.046), whereas no significant difference was observed between the CL and the non-CL (P = 0.698).

CONCLUSION

The reduced signal intensity in the CL on Gd-EOB-DTPA-enhanced MRI could be explained by the decreased uptake of Gd-EOB-DTPA via Oatp1a1 protein in the congestive area.

Retrograde-outflow percutaneous isolated hepatic perfusion using cisplatin: A pilot study on pharmacokinetics and feasibility

OBJECTIVES

This study aimed to evaluate the feasibility and underlying pharmacokinetics of the retrograde-outflow technique for percutaneous isolated hepatic perfusion (PIHP).

METHODS

Retrograde-outflow PIHP was performed in 12 male pigs (weight, 37-44 kg) by redirecting hepatic outflow through the portal vein. Blood with cisplatin (2.5 mg/kg) in an extracorporeal circuit was circulated through the liver under isolation using rotary pumps with balloon catheters. Hepatic angiographic examinations were conducted during perfusion, and histopathological examinations of the organs were conducted after perfusion. The maximum platinum concentration (C max), area under the concentration-time curve (AUC), and chronologic laboratory data were measured.

RESULTS

Retrograde-outflow isolated hepatic angiography confirmed that contrast media flowed into the portal veins in all 12 pigs. The hepatic veins and inferior vena cava were not opacified. Hepatic C max (86.3 mg/l) was 39-fold greater than systemic C max (2.2 mg/l), and hepatic AUC (1330.8 min · mg/l) was 30-fold greater than systemic AUC (44.6 min · mg/l). Histopathological examinations revealed no ischaemic changes or other abnormalities in the liver, duodenum, small intestine, or colon. Within 1 week of the procedure, chronologic laboratory data (n = 3) normalized or returned to pre-therapy levels.

CONCLUSIONS

The retrograde-outflow technique appears to enable safe and feasible PIHP therapy.

KEY POINTS

• The portal vein acted as an outflow tract under retrograde-outflow PIHP. • Plasma hepatic-to-systemic exposure ratio was 39.2 for the maximum platinum concentration. • Plasma hepatic-to-systemic exposure ratio was 29.8 for the AUC. • The retrograde-outflow technique appears to enable safe and feasible PIHP.

Interventional treatment for unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer and third leading cause of cancer-related death in the world. The Barcelona clinic liver cancer classification is the current standard classification system for the clinical management of patients with HCC and suggests that patients with intermediate-stage HCC benefit from transcatheter arterial chemoembolization (TACE). Interventional treatments such as TACE, balloon-occluded TACE, drug-eluting bead embolization, radioembolization, and combined therapies including TACE and radiofrequency ablation, continue to evolve, resulting in improved patient prognosis. However, patients with advanced-stage HCC typically receive only chemotherapy with sorafenib, a multi-kinase inhibitor, or palliative and conservative therapy. Most patients receive palliative or conservative therapy only, and approximately 50% of patients with HCC are candidates for systemic therapy. However, these patients require therapy that is more effective than sorafenib or conservative treatment. Several researchers try to perform more effective therapies, such as combined therapies (TACE with radiotherapy and sorafenib with TACE), modified TACE for HCC with arterioportal or arteriohepatic vein shunts, TACE based on hepatic hemodynamics, and isolated hepatic perfusion. This review summarizes the published data and data on important ongoing studies concerning interventional treatments for unresectable HCC and discusses the technical improvements in these interventions, particularly for advanced-stage HCC.

Intrahepatic blood flow redistribution after temporary occlusion of the middle hepatic vein during right lobe liver donation: report of a case

INTRODUCTION

One of the critical factors that influence graft function after live donor liver transplantation is the presence or absence of global or sectorial liver congestion. Many authors advocate for routine middle hepatic vein (MHV) reconstruction because it is often difficult to determine when the MHV or one of its major branches have functional significance. Predictive tests to assess hemodynamic and functional significance of the MHV and its tributaries are still under study.

CASE REPORT

We have described a novel intraoperative manipulation and Doppler ultrasonographic evaluation that led to the decision to include the MHV with the right lobe graft.

Hemodynamics in rat liver tumor model during retrograde-outflow isolated hepatic perfusion with aspiration from the portal vein: angiography and in vivo microscopy

BACKGROUND

Orthograde percutaneous isolated hepatic perfusion (IHP) techniques using balloon occlusion catheters are relatively simple and facilitate repeated therapy, but they result in higher rates of leakage from the perfusion circuit into the systemic circulation. Therefore, a feasible protocol for percutaneous IHP with less leakage is required.

PURPOSE

To investigate hemodynamic changes in rat liver and tumor during retrograde-outflow isolated hepatic perfusion (R-IHP) with aspiration from the portal vein (PV).

MATERIAL AND METHODS

Animal experiments were approved by the Animal Experiment Ethics Committee of Lund University. Eighteen rats underwent R-IHP after laparotomy and catheterization of the PV and hepatic artery (HA). The HA, inferior vena cava (IVC), and PV were ligated, and flow through the suprahepatic IVC was controlled with a suture loop. The rats were divided into two groups to examine blood flow during R-IHP. Four rats (group 1) underwent arteriography via the HA with and without R-IHP, and 14 rats (group 2) were inoculated with tumor and examined by in vivo fluorescence microscopy of liver and tumor during R-IHP.

RESULTS

In group 1, hepatic arteriography during R-IHP confirmed arterioportal communication in all four rats, with the PV acting as an outflow tract. In vivo fluorescence microscopy in group 2 showed strong enhancement of tumors, and no blood supply from the portal venules to the tumors was seen in any of the 14 rats. Blood flow in the major portion of the hepatic lobules was stopped and the percentage of enhanced area was significantly lower in the normal hepatic lobules than in the tumors (P < 0.0001).

CONCLUSION

We confirmed reversal of blood flow concomitant with good perfusion of the liver tumor and with reduced perfusion of normal liver parenchyma during R-IHP.

Detection of intrahepatic veno-venous shunts by three-dimensional venography using multidetector-row computed tomography during angiography

PURPOSE

The hepatic vein (HV) can be removed during hepatectomy if there is an effective intrahepatic veno-venous shunt (vv-shunt). We evaluated the efficacy of vv-shunt detection by three-dimensional (3D) venography reconstructed from multidetector-row computed tomography (MDCT) during angiography.

METHODS

3D venography was reconstructed using computer software in 88 patients with intrahepatic tumors.

RESULTS

We found that 12 patients had one shunt [4 right hepatic vein (RHV)-middle hepatic vein (MHV) and 12 RHV- inferior right hepatic vein (IRHV)] and 1 patient had 2 shunts (RHV-MHV and -IRHV), confirming a clinically efficient vv-shunt in 14.8% of the patients. In one patient with an RHV-IRHV shunt, the preserved RHV-IRHV shunt worked well and prevented congestion of the postero-caudal subsegment after central bisegmentectomy with partial resection of the RHV ventral trunk for huge hepatocellular carcinoma (HCC).

CONCLUSIONS

Although the vv-shunt detection rate by 3D venography is low, a visualized vv-shunt proved to be efficient. Thus, invasive occlusion venography is avoidable if a vv-shunt is seen on 3D venography.

Transcatheter arterial chemoembolization based on hepatic hemodynamics for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer-related deaths in the world. The Barcelona Clinic Liver Cancer (BCLC) classification has recently emerged as the standard classification system for clinical management of patients with HCC. According to the BCLC staging system, curative therapies (resection, transplantation, and percutaneous ablation) can improve survival in HCC patients diagnosed at an early stage and offer potential long-term curative effects. Patients with intermediate-stage HCC benefit from transcatheter arterial chemoembolization (TACE), and those diagnosed at an advanced stage receive sorafenib, a multikinase inhibitor, or conservative therapy. Most patients receive palliative or conservative therapy only, and approximately 50% of patients with HCC are candidates for systemic therapy. TACE is often recommended for advanced-stage HCC patients all over the world because these patients desire therapy that is more effective than systemic chemotherapy or conservative treatment. This paper aims to summarize both the published data and important ongoing studies for TACE and to discuss technical improvements in TACE for advanced-stage HCC.

Portal uptake function in veno-occlusive regions evaluated by real-time fluorescent imaging using indocyanine green

BACKGROUND & AIMS

Although recent advances in preoperative imaging have enabled accurate estimation of the regional liver volume with venous occlusion, the extent of functional decrease in such regions remains unclear. In this study, the portal uptake function in postoperative veno-occlusive regions and non-veno-occlusive regions was evaluated by intraoperative fluorescent imaging after intravenous injection of indocyanine green (ICG).

METHODS

In 22 liver resection patients and 23 recipients and 18 donors of liver transplantation, fluorescent intensity on the remnant liver or the liver graft was evaluated in real time following intravenous injection of ICG (0.0025 mg per 1 ml of remnant liver volume).

RESULTS

Plateau ICG concentrations were significantly lower in the veno-occlusive regions (C(VO)) than in the non-veno-occlusive regions (C(Non)) in liver resection patients (median [range], 0.75 [0.29-2.0]μg/ml vs. 3.0 [0.46-6.4]μg/ml, p<0.001), donors (0.69 [0.29-1.9]μg/ml vs. 2.4 [0.46-6.4]μg/ml, p<0.001), and recipients (0.75 [0.34-1.8]μg/ml vs. 1.8 [0.54-6.4]μg/ml, p<0.001). Distributions of the C(VO)/C(Non) and the ratio of the hepatic uptake rate constant in the veno-occlusive regions to that in non-veno-occlusive regions were both around 40% (mean ± standard deviation, 0.36 ± 0.17 and 0.42 ± 0.16, respectively). When the functional remnant liver volume was calculated as a sum of non-veno-occlusive regions and veno-occlusive regions multiplied by C(VO)/C(Non), its ratio to the total liver volume was correlated with the improved postoperative/preoperative ratio of prothrombin time.

CONCLUSIONS

Portal uptake function in veno-occlusive regions is approximately 40% of that in non-veno-occlusive regions. Intraoperative ICG-fluorescent imaging enables real-time evaluation of the extent of the functional decrease in veno-occlusive regions, enhancing accurate estimation of the hepatic functional reserve for determining the surgical indications and procedures.

Perfusion and parenchymal changes related to vascular alterations of the liver

Imaging plays a significant role in the diagnosis of vascular abnormalities of the liver and sometimes provides the only clue to the correct diagnosis. With advances of imaging techniques and multiphasic acquisition of liver imaging, various perfusion changes are frequently encountered. Correct imaging diagnosis of significant vascular diseases can prompt appropriate work-up and timely management. Accurate differentiation of clinically insignificant perfusion phenomena from clinically significant findings including neoplastic conditions and in the setting of post-transplantation is essential. This pictorial essay illustrates various perfusion and parenchymal changes associated with portal venous inflow, hepatic venous outflow, and non-portal venous third inflow and describes brief background pathophysiology and differential points.

Obstruction at middle hepatic venous tributaries in modified right lobe grafts after living-donor liver Transplantation: diagnosis with contrast-enhanced US

PURPOSE

To investigate the ability of contrast material-enhanced ultrasonography (US) to help diagnose obstruction of middle hepatic venous (MHV) tributaries soon after living-donor liver transplantation with modified right lobe grafts.

MATERIALS AND METHODS

The institutional review board approved the study and waived requirement for informed consent. Sixty-five consecutive patients (48 men, 17 women; mean age, 52.8 years; range, 33-69 years) who underwent living-donor liver transplantation with modified right lobe grafts between February and May 2009 were included. All patients underwent contrast-enhanced US and Doppler US on postoperative day 1 and underwent computed tomography (CT) within 7 days after US. At contrast-enhanced US, parenchymal enhancement patterns in the territory of each MHV tributary during arterial and portal venous phases were evaluated. With use of most frequent enhancement patterns in patients with obstruction at MHV tributaries as a criterion, diagnostic performance of contrast-enhanced US was compared with that of Doppler US for diagnosis of obstruction at MHV tributaries; CT was the reference standard. Generalized estimating equations were used to adjust for data clustering.

RESULTS

Of 148 MHV tributaries in 65 patients, 36 (24.3%) in 31 patients were diagnosed as obstructed at CT. With arterial high echogenicity or portal low echogenicity used as a criterion for hepatic venous obstruction, contrast-enhanced US had sensitivity, specificity, and accuracy of 91% (33 of 36), 97% (109 of 112), and 95% (142 of 148), respectively, whereas Doppler US had values of 83% (30 of 36), 86% (97 of 112), and 85% (127 of 148), respectively. Contrast-enhanced US was significantly more specific and accurate than Doppler US for diagnosis of obstruction at MHV tributaries (P=.024 and .01, respectively). Arterial high echogenicity was noted only in the hepatic venous obstruction group.

CONCLUSION

Contrast-enhanced US can help accurately assess hepatic venous obstruction at MHV tributaries after living-donor liver transplantation with a modified right lobe graft. Contrast-enhanced US was significantly more specific than Doppler US, with arterial hyperenhancement in the affected area being specific to hepatic venous obstruction.

Hepatofugal portal venous flow on Doppler sonography after liver transplantation. Analysis of presumed causes based on radiologic and pathologic features

OBJECTIVES

The purpose of this study was to categorize hepatofugal portal venous flow on Doppler sonography after liver transplantation and to investigate its clinical importance and presumed causes based on radiologic and pathologic findings.

METHODS

This retrospective study was approved by our Institutional Review Board, and the requirement for informed consent was waived. Examination of our database over 4 years revealed 30 patients in whom Doppler sonography showed hepatofugal portal venous flow during follow-up periods. We investigated its occurrence and clinical features, including radiologic and pathologic findings, and classified the possible causes into 5 types: A, systemic problems; B, gross vascular abnormalities correctable by intervention; C, specific cardiac problems; D, microscopic abnormalities of the graft; and E, miscellaneous. We classified the patterns of hepatofugal portal venous flow into continuous hepatofugal or hepatofugal-dominant to-and-fro flow and hepatopetal-dominant to-and-fro flow, and we investigated the relationship of the presumed causes and flow patterns with the clinical course.

RESULTS

The incidence of hepatofugal portal venous flow was 2.38%. The overall mortality rate was 26.67% (95% confidence interval, 11.1%-42.9%): all patients (n = 5) in group A, 1 in group C, and 2 in group D, died. Possible cause type B and a mainly hepatopetal flow pattern were good prognostic factors (P = .031 and .018, respectively).

CONCLUSIONS

Hepatofugal portal venous flow reflects diverse pathologic conditions after liver transplantation, and its clinical importance also differs depending on the cause.

Acute outflow obstruction of hepatic veins in rabbits: quantitative analysis of hepatic perfusion with contrast-enhanced sonography

OBJECTIVES

To compare time-enhancement curve parameters of contrast-enhanced sonography in acute partial hepatic venous outflow obstruction with those of a baseline study.

METHODS

Contrast-enhanced sonography was performed in 11 rabbits with bolus administration of a sulfur hexafluoride contrast agent (0.1 mL/kg). After baseline scanning for 3 minutes, a 5.3F balloon catheter was placed into the left hepatic vein. Obstruction was artificially induced by 0.4-mL balloon inflation, and sonography was repeatedly performed thereafter. On images stored with 1-second intervals, 2 × 2-mm regions of interest were placed, and mean luminosity was measured. Time-enhancement curves were plotted, and contrast arrival times, peak enhancement values, peak enhancement times, 50% wash-out times, and 3-minute wash-out rates were obtained. Paired t tests were performed to evaluate the significance of differences in the parameters between baseline and obstruction.

RESULTS

On baseline sonography, the median contrast arrival time, peak enhancement value, peak enhancement time, 50% wash-out time, and 3-minute wash-out rate were 6 (range, 4-8; mean ± SD, 5.9 ± 1.2) seconds, 188.5 (104.7-209.5; 178.4 ± 33.1) arbitrary units, 19 (14-27; 19.8 ± 4.1) seconds, 75 (60-101; 78.2 ± 13.9) seconds, and 89.7% (81.3%-95.1%; 88.4% ± 4.9%), respectively. With obstruction, those values were 7 (5-12; 6.9 ± 2.3) seconds, 202.8 (98.2-215.1; 186.0 ± 39.3) arbitrary units, 31 (17-59; 32 ± 11.6) seconds, 101 (47-136; 96.2 ± 23.6) seconds, and 79.2% (66.2%-88.8%; 79.1% ± 7.6%). Compared with baseline, the peak enhancement time was significantly delayed from 19 to 31 seconds (P = .0027), 50% wash-out time significantly delayed from 75 to 101 seconds (P = .0209), and 3-minute wash-out rate significantly decreased from 89.7% to 79.2% (P < .0001) with obstruction, but there were no significant differences in contrast arrival times and peak enhancement values (P = .0756 and .2179).

CONCLUSIONS

Contrast-enhanced sonography can provide quantitative assessment of microbubble congestion in partial hepatic venous outflow obstruction. The peak enhancement time and 50% wash-out time are delayed and 3-minute wash-out rate is decreased in rabbits with artificially induced obstruction compared with a baseline study.

Radiological assessment of hepatic vein invasion by hepatocellular carcinoma using combined computed tomography hepatic arteriography and computed tomography arterial portography

PURPOSE

The aim of this study was to elucidate computed tomography hepatic arteriography (CTHA) and CT arterial portography (CTAP) findings characteristic of hepatocellular carcinoma (HCC) with large hepatic venous invasion (HVI) and then to examine whether the presence of minute HVI can be diagnosed based on each finding.

MATERIALS AND METHODS

Combined CTHA and CTAP of 106 HCCs were examined. Two radiologists analyzed the radiological findings of five nodules with large HVI (group vv2). The remaining 101 nodules were classified into two groups: group vv1, positive minute HVI; group vv0, negative HVI. They examined whether each finding observed in group vv2 could be detected in groups vv1 and vv0.

RESULTS

Analysis of group vv2 identified (a) tumor thrombus, (b) early inflow of the contrast into the hepatic vein proximal to the invaded site, and (c) partially decreased portal venous flow in the peripheral parenchyma subject to the involved hepatic vein. Findings (b) and (c) were observed in 16% of group vv1. A significant difference in frequency of finding (c) was obtained between groups vv1 and vv0. The positive and negative predictive values of finding (c) were 66.7% and 77.9%, respectively.

CONCLUSION

Findings (b) and (c), especially the latter, may partly contribute to the radiological diagnosis of minute HVI.

Analysis of intrahepatic venovenous shunt by hepatic venography

BACKGROUND

The necessity of preserving hepatic venous drainage in hepatectomy and liver transplantation has recently been accepted; however, the hepatic vein (HV) can be removed when an effective intrahepatic venovenous shunt (VV shunt) exists.

METHODS

Occlusion venography of the right HV (RHV) was performed in 51 patients to investigate the VV shunt characteristics.

RESULTS

Twenty patients had a shunt between the RHV and large HVs whose root diameters were >3 mm, such as the superficial or inferior RHV, or the middle HV. Twenty patients had a shunt between the RHV and small HVs with root diameters < or =3 mm. Eleven patients had no shunt. The change in anterior portal vein blood flow after RHV occlusion, evaluated by Doppler ultrasonography, was minimal (5 +/- 3%) in patients with a shunt between the RHV and large HVs, and less than in patients with a shunt between the RHV and small HVs (38% +/- 18%) or without a shunt (50% +/- 17%; P < .0001). A shunt between the RHV and large HV was less frequently seen in those patients with cirrhosis (3/20) than in those without cirrhosis (17/31; P = .0044). The existence of the shunt between the RHV and large HVs was unpredictable, however, from computed tomographic findings or laboratory data.

CONCLUSION

A hemodynamically significant VV shunt between the RHV and large HV was observed in fewer than half of the patients and less frequently in cirrhotic patients. Preservation of hepatic venous drainage should be considered in patients without a hemodynamically significant VV shunt in liver surgery.

Interventional oncology: new options for interstitial treatments and intravascular approaches: right hepatic vein embolization after right portal vein embolization for inducing hypertrophy of the future liver remnant

Extensive hepatic resection is often associated with post-hepatectomy liver failure. Owing to the regenerative capacity of the liver, preoperative portal vein embolization (PVE) has been proposed to increase the functional mass of the non-embolized liver segments that will remain in situ after surgery. However, in some patients, hypertrophy of the non-embolized liver segments following PVE is insufficient to support major hepatectomy. Several studies have demonstrated alternative techniques for inducing hypertrophy of the non-embolized liver segments, including PVE in conjunction with hepatic arterial embolization or hepatic vein embolization in conjunction with PVE. Investigation of new techniques for inducing hypertrophy of the future liver remnant can reasonably be expected to expand the selection criteria for extensive hepatic resection.

Right hepatic vein stenosis at anastomosis in patients after living donor liver transplantation: optimal Doppler US venous pulsatility index and CT criteria--receiver operating characteristic analysis

PURPOSE

To establish optimal Doppler ultrasonographic (US) venous pulsatility index and computed tomographic (CT) criteria for right hepatic vein (RHV) stenosis after living donor liver transplantation (LDLT) and to compare accuracies of these methods by using receiver operating characteristic (ROC) analysis.

MATERIALS AND METHODS

This retrospective study was approved by an institutional review board; informed consent was waived. Eighty patients (48 men, 32 women; mean age, 51.5 years +/- 9.2 [standard deviation]) underwent Doppler US and CT within 8 days of hepatic venography following right lobe LDLT between October 2006 and September 2008. At venography, RHVs were classified into a stenosis or nonstenosis group. At Doppler US, venous pulsatility index was defined as the difference between maximum and minimum frequency shifts divided by maximum frequency shift. At CT, diameters of anastomosis and RHV were measured; percentage of stenosis was calculated. Mean Doppler US and CT parameters in the two groups were compared; ROC analysis was performed.

RESULTS

There were 30 stenotic and 50 nonstenotic RHVs. Mean venous pulsatility index and mean anastomosis diameter were significantly lower and mean percentage of stenosis was significantly higher in the stenosis than the nonstenosis group (P < .001 each). Optimal cutoffs for venous pulsatility index, anastomosis diameter, and percentage of stenosis were 0.16, 3.7 mm, and 47%, respectively. Sensitivity and specificity were 86.7% and 68.0% for venous pulsatility index, 96.7% and 88.0% for anastomosis diameter, and 96.7% and 86.0% for percentage of stenosis, respectively. At ROC analysis, anastomosis diameter (P = .002) and percentage of stenosis (P = .003) were significantly more accurate than venous pulsatility index.

CONCLUSION

CT is more accurate than Doppler US for RHV stenosis after LDLT, with venous pulsatility index as the sole sonographic criterion. Patients suspected of having RHV stenosis at Doppler US may benefit from CT to reduce unnecessary venography.

Nontumorous arterioportal shunts in the liver: CT and MRI findings considering mechanisms and fate

The intrahepatic non-tumorous arterioportal shunt (APS) is one of the important causes of transient hepatic enhancement differences (THED) on dynamic CT or MRI. Most small APSs are located in the peripheral portion of the liver. Because of the parenchymal distortion in the advanced cirrhotic liver, many small APSs tend to show an amorphous or nodular appearance, making them difficult to distinguish from hypervascular tumors. In addition to the use of dynamic CT or MRI, iso-attenuation densities or iso-intensities on pre-contrast and equilibrium phases, MRI using a liver-specific contrast agent can be useful to characterize the hypervascular pseudolesions. Because there is no difference in water diffusion in the hepatic parenchyma in the region of the APS, diffusion-weighted MRI also has great potential to distinguish non-tumorous shunts from true focal lesions. Larger (>2 cm) APSs of direct arterio-portal venous fistulas from extrinsic insults show typical subcapsular wedge-like THEDs that are only temporarily depicted several months after the traumatic event; most of these THEDs gradually decrease in size or vanish completely. By understanding the nature of non-tumorous APSs, radiologists will be able to provide a more accurate assessment of many THEDs during daily interpretations of CT or MR images of the liver.

Optimal acquisition delay for dynamic contrast-enhanced MRI of hypervascular hepatocellular carcinoma

OBJECTIVE

The purpose of this study was to prospectively determine the optimal acquisition delay for imaging of hypervascular hepatocellular carcinoma with multiphasic dynamic contrast-enhanced MRI.

SUBJECTS AND METHODS

One hundred twenty patients with chronic hepatic disease underwent three-phase dynamic contrast-enhanced MRI of the liver, which revealed 49 hypervascular hepatocellular carcinomas. Abdominal aortic contrast arrival time was determined with test bolus imaging. Patients were assigned to one of the following four groups according to acquisition delay determined from abdominal aortic contrast arrival time to the middle of the k-space for the early, late hepatic arterial, and portal venous phases: 0, 12, and 49 seconds (group 1); 3, 15, and 52 seconds (group 2); 6, 18, and 55 seconds (group 3); and 9, 21, and 58 seconds (group 4). Each phase of imaging took 12 seconds. Contrast enhancement in the abdominal aorta, portal vein, hepatic parenchyma, and hepatocellular carcinoma was evaluated. Peritumoral sinusoidal enhancement (i.e., coronal enhancement) also was assessed.

RESULTS

Intense enhancement of hepatocellular carcinoma with little background parenchymal enhancement occurred at 9-12 seconds (p < 0.05) after arrival of contrast material in the abdominal aorta. Hepatocellular carcinoma-to-liver contrast began to decline at 15 seconds and decreased to less than zero at 49 seconds. The conspicuity of coronal enhancement was greater 21 seconds after contrast administration than in earlier phases.

CONCLUSION

With the injection protocol used in this study, optimal acquisition delay-determined from abdominal aortic contrast arrival time to the middle of the k-space acquisition-for imaging of hypervascular hepatocellular carcinoma was 9-12, 21 or more, and 49 seconds for the early, late hepatic arterial, and portal venous phases.

Sinusoidal perfusion in the veno-occlusive region of living liver donors evaluated by indocyanine green and near-infrared spectroscopy

Split liver transplantation and living donor liver transplantation (LDLT) commonly use a right liver graft without the middle hepatic vein (MHV). Although tributaries of the MHV are not reconstructed in the majority of cases, the alterations of the microcirculation and its regional functions remain unknown. We addressed these issues by assessing liver tissue indocyanine green (ICG) uptake with near-infrared spectroscopy (NIRS) in 21 donors. After graft procurement, visual inspection (before and after hepatic arterial clamping) and Doppler examination of the veno-occlusive region were performed. Bolus ICG (100 microg/kg) was then administered intravenously. Blood ICG at the finger tip was measured with pulse dye densitometry, whereas the liver ICG concentrations in the veno-occlusive and non-veno-occlusive regions were simultaneously measured for 15 minutes by NIRS. We estimated the hepatic ICG uptake rate constants in the veno-occlusive region (Ku-oc) and non-veno-occlusive region (Ku-non). Changes in sinusoidal perfusion in the veno-occlusive region were expressed by the ratio of Ku-oc to Ku-non (Roc/non). The median value of Roc/non was 0.47, although it ranged from 0.13 to 0.94. Roc/non was related to the extent of liver surface discoloration before and after hepatic arterial clamping (P = 0.03 and 0.01, respectively). In conclusion, sinusoidal perfusion was impaired in the veno-occlusive regions of living donor livers, but the magnitude of the effect varied greatly. Measurement of hepatic ICG uptake by NIRS could become a valuable tool for assessing the indication for venous reconstruction in LDLT and/or split donor liver transplantation.

Doppler sonography to diagnose venous congestion in a modified right lobe graft after living donor liver transplantation

OBJECTIVE

The objective of our study was to assess the value of Doppler sonography for the diagnosis of hepatic venous congestion in a modified right lobe graft during the early postoperative period after living donor liver transplantation.

SUBJECTS AND METHODS

Doppler sonography examinations were prospectively performed in 54 patients within 24 hours after living donor liver transplantation with a modified right lobe graft in which large (> 5 mm) middle hepatic vein (MHV) tributaries were reconstructed. The number, flow direction, and waveform of the MHV tributaries; the echogenicity of the surrounding parenchyma; and the flow direction of the corresponding portal branch were evaluated. Hepatic venous congestion was diagnosed when there was no color flow or a monophasic waveform of an MHV tributary. The sensitivity of Doppler sonography for the detection of MHV tributaries was assessed using donors' preoperative CT scans and surgical records as references. The diagnostic values of Doppler sonography for hepatic venous congestion were assessed using recipients' postoperative CT scans as references. Differences in prevalence of Doppler sonography findings between the group with hepatic venous congestion and the non-hepatic venous congestion group were assessed.

RESULTS

Doppler sonography enabled us to identify 90% (155/173) of all and 98% (129/131) of the large MHV tributaries. The sensitivity and specificity of Doppler sonography for hepatic venous congestion were 90% (28/31) and 77% (96/124), respectively, for all and 88% (15/17) and 85% (95/112), respectively, for large MHV tributaries. Parenchymal hyperechogenicity was more commonly seen in the hepatic venous congestion group (65%, 20/31) than in non-hepatic venous congestion group (6%, 7/124) (p < 0.01). All five MHV tributaries with reversed flow were seen in the non-hepatic venous congestion group. All five portal branches with hepatofugal flow were seen in the hepatic venous congestion group.

CONCLUSION

Doppler sonography provides a reliable noninvasive surveillance tool for hepatic venous congestion in a modified right lobe graft during the early postoperative period after living donor liver transplantation.

Left Renal Vein Graft for Vascular Reconstruction in Abdominal Malignancy

BACKGROUND

Advanced abdominal malignancies are occasionally invasive for the major blood vessels, such as the portal vein (PV), inferior vena cava (IVC), and major hepatic veins (HVs), and complete removal of the tumors is required for patients undergoing vascular resection and reconstruction. We used left renal vein (LRV) grafts for vascular reconstruction in patients with these malignancies and evaluated their clinical relevance.

METHODS

A total of 113 patients underwent vascular resection including the PV (42 patients), IVC (68 patients), and HV (3 patients) for hepatobiliary-pancreatic or abdominal tumor resection. Of these, 11 patients underwent vascular reconstruction with a LRV graft of the PV, superior mesenteric vein (SMV), and HVs in 3 patients each, and the IVC in 2 patients. The HVs were resected with segmentectomy involving Couinaud's segments VII, VIII, and IV; VII, VIII, and II; or III, IV, VIII in each patient. The PV and SMV were resected in 5 patients undergoing pancreaticoduodenectomy for pancreatic carcinoma, and in 1 patient being treated with extended right hepatectomy and pancreaticoduodenectomy for hepatic hilar carcinoma. The IVC was partially resected in 1 patient with advanced colon cancer and 1 with malignant schwannoma.

RESULTS

The mean graft length of LRV obtained was 3.6 (3.5-4.0) cm. The graft was used as a tube in 9 patients, and as a patch in 2 patients. The mean duration of clamping time was 41.9 (35-60) min. Portal vein thrombosis was encountered in 2 patients, and anastomotic stenosis in 1 patient. Other morbidity was not related to vascular reconstruction. One patient who underwent extended right hepatectomy and pancreaticoduodenectomy died of liver failure in the hospital. The serum creatinine level after surgery did not deteriorate except in the one patient who died in the hospital. Graft patency was maintained during the follow-up period in all patients.

CONCLUSIONS

A LRV graft may enhance the possibility of vascular reconstruction without deteriorating serum creatinine level, and it provides sound graft patency.

Haemodynamic changes in the liver under balloon occlusion of a portal vein branch: evaluation with single-level dynamic computed tomography during hepatic arteriography

AIM

To assess haemodynamic changes in the liver under temporary occlusion of an intrahepatic portal vein.

MATERIALS AND METHODS

Between February 2000 and October 2004, 16 patients with hepatobiliary disease underwent single-level dynamic computed tomography during hepatic arteriography (SLD-CTHA) under temporary balloon occlusion of an intrahepatic portal vein. All patients needed percutaneous transhepatic portography for therapy of their disease. SLD-CTHA was undertaken to clarify the time-attenuation curve influenced by portal vein occlusion, and it was performed continuously over a period of 30s. The difference in absolute attenuation of the liver parenchyma in segments with occluded and non-occluded portal vein branches was determined by means of the CT number, and the difference in absolute attenuation of the occluded and non-occluded portal veins themselves was also evaluated.

RESULTS

SLD-CTHA demonstrated a demarcated hyperattenuation area in the corresponding distribution of the occluded portal vein branch. The attenuation of the liver parenchyma supplied by the occluded portal vein was significantly higher than that in the non-occluded area (p<0.01). The balloon-occluded portal branch enhancement in 15 of 16 cases (94%) appears due to arterio-portal communications. Failure to evaluate a remaining case for portal branch enhancement was due to absence of a visualized portal branch in the section.

CONCLUSION

Under temporary occlusion of an intrahepatic portal vein, hepatic angiography produced enhancement of the occluded portal branches and their corresponding parenchymal distribution; this finding is considered consistent with the presence of arterio-portal communications.

Hepatic Venous Congestion After Right-lobe Living-donor Liver Transplantation

PURPOSE

To describe and determine the additional value of delayed-phase imaging of hepatic venous congestion after living-donor liver transplantation.

MATERIALS AND METHODS

Twenty-eight patients who had surgical ligation of the middle hepatic vein (HV) in living-donor liver transplantation underwent 3-phase computed tomography scans. Two radiologists analyzed in consensus the presence and pattern of the hepatic attenuation difference and the opacification of the HV in the congested areas of the liver during each phase of the initial and follow-up computed tomography scanning. The imaging findings were correlated with the serum bilirubin level.

RESULTS

Opacification of the HV was observed more frequently in 22 (92%) of 24 hyperattenuating areas on delayed-phase (DP) scans than in 2 (50%) of 4 hypoattenuating areas in the congested areas of the liver. Patients with persistent hypoattenuatation in the congested areas on all phases (14%) showed significantly persistent hyperbilirubinemia after postoperative 4 weeks and showed a higher mortality rate (50%) than did the other patients with hyperattenuation on DP scans.

CONCLUSIONS

A hypoattenuating area of the liver during DP scans indicates severe hepatic congestion and is correlated with hyperbilirubinemia and a high mortality rate.

Portal and hepatic vein thrombosis in liver abscess: CT findings

OBJECTIVE

Our aim is to describe imaging findings of portal and hepatic vein thrombosis in pyogenic liver abscess on contrast-enhanced MDCT and to determine the incidence and evolving patterns on follow-up imaging.

METHODS

Over a 5-year period, 67 patients with liver abscess underwent single-phase (n=30) or triphasic (n=37) contrast-enhanced CT. Images were reviewed for the presence of portal vein (PV) or hepatic vein (HV) thrombosis, regional parenchymal attenuation, and changes on follow-up CT.

RESULTS

Venous thrombosis was seen in 28/67 patients (42%), involving PV in 16/67 (24%) and HV vein in 15/67 (22%); 3/67 (4%) had both PV and HV thrombosis. Thrombosis was seen as non-enhancing linear structures without expanding the lumen in all cases. Regional parenchymal attenuation during the portal-phase was hyperattenuating (10/16, 63%) or isoattenuating (6/16, 38%) in PV thrombosis, and mostly hypoattenuating (13/15, 87%) in HV thrombosis (P<.001). Of 27 patients with follow-up contrast-enhanced CT, venous thrombosis resolved in 10/27 (37%) within 6 months and persisted in 17/27 (63%) for 3-38 months, including 13 PV thrombosis and 4 HV thrombosis. Interval parenchymal atrophy was seen only in four all with persistent PV thrombosis.

CONCLUSIONS

Both PV and HV thrombosis frequently occurs in liver abscess and is seen as non-enhancing linear structures without expanding the lumen on contrast-enhanced CT. Regional attenuation changes in hepatic vein thrombosis were often hypoattenuating whereas none with portal vein thrombosis showed hypoattenuation.

Impact of venous drainage on regeneration of the anterior segment of right living-related liver grafts

The effect of additional venous reconstruction on morphologic and functional regeneration of the anterior segment of right-lobe liver grafts was compared among three groups according to graft type: right liver graft without the middle hepatic vein (MHV) or MHV tributaries (n=7), with MHV tributaries (n=25) and with the MHV (n=10). Whole graft volume (GV) and anterior segment volume (ASV) were estimated from CT scans and post-operative laboratory data and daily ascitic fluid volume were examined. Peak GV in each group was reached two or three wk after surgery. The ASV/GV ratios of the grafts with the MHV or MHV tributaries were higher than those of grafts without additional venous reconstruction. However, the asparate aminotransferase and ascitic fluid volume values in the group that received grafts with MHV tributaries were higher than in the group that received grafts with the MHV in the same period. Although rapid enlargement of the anterior segment of right-lobe grafts with MHV tributaries occurred in the early post-operative period, complete functional liver regeneration may not occur even after additional tributary reconstruction. These results suggest that the selection of right-lobe grafts with the MHV is more beneficial for recipients, as long as donor safety is protected and that as many MHV tributaries as possible should be reconstructed in right-lobe grafts without MHV.

Branching patterns and drainage territories of the middle hepatic vein in computer-simulated right living-donor hepatectomies

Full right hepatic grafts are most frequently used for adult-to-adult living donor liver transplantation (LDLT). One of the major problems is venous drainage of segments 5 and 8. Thus, this study was designed to provide information on venous drainage of right liver lobes for operation-planning. Fifty-six CT data sets from routine clinical imaging were evaluated retrospectively using a liver operation-planning system. We defined and analyzed venous drainage segments and the impact of anatomic variations of the middle hepatic vein (MHV) on venous outflow from segments 5 and 8. MHV variations led to significant shifts of segment 5 drainage between the middle and right hepatic vein. In cases with the most frequent MHV branching pattern (n = 33), a virtual hepatectomy closely right to the MHV intersected drainage vessels that provided drainage for 30% of the potential graft, not taking into account potential veno-venous shunts. In individuals with inferior MHV branches that extend far into segments 5 and 6 (n = 10), the overall graft volume at risk of impaired venous drainage increased by 5% (p < 0.001). If this is confirmed in clinical trials and correlated with intraoperative findings, the use of liver operation-planning systems would be beneficial to improve overall outcome after right lobe LDLT.

Hepatic metastases: perilesional enhancement on dynamic MRI

OBJECTIVE

Our purpose was to determine whether the perilesional parenchymal enhancement of hepatic metastases could be correlated with tumoral enhancement on arterial phase images or tumor size on dynamic MRI.

MATERIALS AND METHODS

One hundred thirty-four lesions of hepatic metastases in 44 patients were subjected to a retrospective analysis of the dynamic MR images obtained with 3D spoiled gradient-echo sequences. The thickness of the enhancing rim on arterial phase images was regarded as a summation of the enhancing component of tumor periphery and perilesional enhancement, which were estimated by the tumor size on precontrast T1-weighted images. The presence of wedge-shaped perilesional enhancement was also correlated with the lesion size.

RESULTS

Except for 17 diffusely enhanced lesions, lesion size was comparable between the lesions with (n = 87; 26 +/- 19 [SD] mm) and without rim enhancement (n = 30; 27 +/- 23 mm) on the arterial phase dynamic MR images (p > 0.05). The degree of peripheral tumoral enhancement showed an inverse correlation (r = -0.389) with the thickness of the circumferential perilesional enhancement (p < 0.001). The mean size of the lesions with wedge-shaped perilesional enhancement (n = 44; 33 +/- 20 mm) was larger than that of the other lesions (n = 90; 25 +/- 19 mm) (p = 0.016).

CONCLUSION

The degree of circumferential perilesional enhancement of hepatic metastases on arterial phase dynamic MR images would be independent of the lesion size but inversely correlated with the degree of peripheral tumoral vascularity. An understanding of these features may help tumor characterization and should prompt hypotheses and studies of microvascular phenomena in tumoral and epitumoral environments.

Triphasic helical CT in Budd-Chiari syndrome: patterns of enhancement in acute, subacute and chronic disease

AIM

To retrospectively evaluate helical computed tomography (CT) findings in a series of consecutive patients with Budd-Chiari syndrome.

METHODS

Patterns of enhancement observed at contrast-enhanced helical CT in 10 consecutive patients (six women, four men; aged 27-51 years) with either acute, subacute or chronic Budd-Chiari syndrome were retrospectively evaluated along with the status of the hepatic veins. All patients underwent triphasic helical CT (10 mm beam collimation, 7 mm rec. intervals, 120 kV, 200-250 mA, pitch = 1.0) performed at 20-25, 70-75 and 300 s after i.v. bolus (3 ml/s) injection of 150 ml iodinated non-ionic contrast media.

RESULTS

Abnormal patterns of enhancement were identified in eight patients. In all patients with acute Budd-Chiari disease (3/3) abnormal arterial enhancement of the caudate lobe, the so-called "fan-shaped pattern" was observed, whereas visible venous thrombosis was only depicted in two. Conversely, a "patchy pattern" of enhancement was observed in five out of seven patients with either sub-acute (2) or chronic Budd-Chiari disease (5) along with a strip-like appearance or lack of visualization of hepatic veins.

CONCLUSIONS

The "fan-shaped" pattern of enhancement represent a characteristic finding of acute Budd-Chiari disease, and it may help to suggest the correct diagnosis even in absence of visible venous thrombosis.

Hepatic Attenuation Differences Associated with Obstruction of the Portal or Hepatic Veins in Patients with Hepatic Abscess

OBJECTIVE

The purpose of our study was to determine the nature of the association between the attenuation difference of the hepatic parenchyma surrounding an abscess and obstruction of the regional portal vein or of the hepatic vein.

MATERIALS AND METHODS

Helical CT scans of 60 patients with hepatic abscess were analyzed for the presence of complete or partial obstruction of the portal or hepatic veins and for attenuation differences in the surrounding parenchyma. Clinical (age, sex, underlying disease, and microorganism) and CT (obstruction of the portal or hepatic vein and number, location, and size of abscesses) findings were analyzed statistically for possible associations with each of regional parenchymal hyper- and hypoattenuation by using the chi-square test and multivariate logistic regression analysis.

RESULTS

Regional parenchymal hyperattenuation was identified in 40 patients (67%). More patients with portal vein obstruction showed regional parenchymal hyperattenuation than patients without portal vein obstruction (22/27 patients vs 18/33, p = 0.028), and more patients with hepatic vein obstruction showed regional parenchymal hypoattenuation than those without hepatic vein obstruction (11/21 vs 3/39, p = 0.0003). Multivariate logistic regression analysis showed that portal venous obstruction was the only statistically significant predictor of regional parenchymal hyperattenuation (p = 0.032; odds ratio, 3.7) and that parenchymal hypoattenuation was associated with hepatic venous obstruction (p = 0.001; odds ratio, 44.9).

CONCLUSION

Parenchymal hypo- and hyperattenuation are frequently observed in the hepatic region surrounding an abscess on dynamic CT. Moreover, these parenchymal attenuation differences are associated with regional portal or hepatic vein obstruction.

Hepatic venous outflow reconstruction in right live donor liver transplantation

The increasing experience with live donor liver transplantation has allowed for the identification of potential morbidities associated with technical considerations. Technical graft failure can be associated with both inflow and outflow vascular compromise. Although the latter has not always been given the relevance of the former, evidence pointing to its pivotal role continues to mount. We believe that impaired venous outflow was a cause of previously unexplained graft failures during our initial experience. Based on this observation, we developed a technique to prevent the "choking" of the graft at the outflow anastomosis with the inferior vena cava (IVC). The enhanced outflow via a cloaca maximum is achieved by reconstructing the graft vessels with preserved veins or arteries (usually iliac vessels are used) from a blood-group-identical or blood-group-compatible deceased organ donor. Alternatively, hepatic vein or portal vein obtained from the resected native liver can be used. The reconstructed common outflow is anastomosed to a triangular opening of the IVC. Such enhanced outflow provides optimal venous drainage, especially during the early phase of growth of the graft.

Peritumoral fat-spared area is well correlated with the presence of temporal peritumoral enhancement in hepatic hemangioma in fatty liver

PURPOSE

To assess the relationship between temporal peritumoral enhancement and peritumoral focal fat sparing adjacent to hepatic hemangiomas.

MATERIALS AND METHODS

On the basis of MRI and sonographic imaging follow-up, 51 hepatic hemangiomas were identified in 37 patients, who had both hepatic hemangiomas and focal fat-sparing areas in fatty liver. Among them, 36 tumors were associated with peritumoral focal fat spares. The association between the temporal peritumoral enhancement in the early arterial phase of dynamic MRI and peritumoral fat sparing in the same hemangioma was investigated. Furthermore, the configuration of the temporal peritumoral enhancement was correlated with that of the peritumoral focal fat-sparing area. We used Chi square and Fisher's exact test for statistic analysis.

RESULTS

A total of 31 out of 36 hemangiomas (86.1%) showed both peritumoral focal fat spares and temporal peritumoral enhancement. The presence of temporal peritumoral enhancement is significantly related to that of peritumoral focal fat-sparing (P < 0.001). A total of 21 of the 31 tumors (67.7%) presented with similar configuration of the peritumoral focal fat-sparing area and temporal peritumoral enhancement area with respect to size and shape. The remaining 10 hemangiomas showed similar shape but slightly different size in these two imaging characteristics.

CONCLUSION

Temporal peritumoral enhancement seen in hepatic hemangioma might be related to focal fatty sparing adjacent to the hemangiomas.

Percutaneous radiofrequency ablation for unresectable large hepatic tumours during hepatic blood flow occlusion in four patients

AIM

To evaluate percutaneous radiofrequency (RF) ablation therapy for unresectable large hepatic tumours combined with regional interruption of hepatic blood flow, and to assess the safety and efficacy of this procedure.

MATERIALS AND METHODS

Four patients with hepatic tumours were enrolled in this study. Patients were treated by a single session of RF ablation during occlusion of both hepatic artery and hepatic vein. Tumour size ranged from 45-57 mm (mean 50.2 mm). Initial therapeutic efficacy was evaluated with helical computed tomography (CT) performed within 9 days after the treatment. CT or magnetic resonance imaging (MRI) was performed every 2-3 months thereafter.

RESULTS

The largest axis of coagulated lesions after the ablation was 50-60 mm (mean 56.5 mm) in diameter. The ablation therapy was considered complete in three patients; after a mean follow-up of 12.7 months, CT and MRI revealed complete destruction of their tumours. One patient required further treatment. No severe complications occurred.

CONCLUSION

Although further studies are needed, in this limited clinical trial a local ablation area exceeding 50 mm in diameter was achieved safely.