Hepatic venous congestion after living donor liver transplantation with right lobe graft: two-phase CT findings

Complications after Thermal Ablation of Hepatocellular Carcinoma and Liver Metastases: Imaging Findings

Tumour ablation is a strategy of treatment of hepatic tumours in patients with small hepatocellular carcinoma (HCC) (<3 cm) or in patients unfit for surgical resection. Moreover, tumor ablation can be used as an adjuvant therapy or may be used in association with resection in case of patients with poor functional liver disease. These types of treatment usually could be performed percutaneously under image guidance. The most clinically verified and used ablation modalities are Radiofrequency Ablation (RFA) and microwave ablation (MWA). However, despite both of them are considered minimally invasive techniques, they could be related to post-procedural complications. The International Working Group on Image-Guided Tumor and the Society of Interventional Radiology (SIR) identified major and minor post-ablative complications. Major complications, as vascular complications, occur in 2.2% to 3.1% of cases and include all the high risk pathological conditions which could increase the level of care or result in hospital admission or substantially prolonged hospital stay (SIR classifications C−E). Minor complications, as biliary complications, occur in 5% to 8.9% and include self-limiting conditions that are considered to be of low risk for the patient’s outcome. The purpose of this review is to summarise the main pathological ultrasound (US) and Computed Tomography (CT) findings, that may arise after ablative treatment. To simplify the analysis, the pathological pictures are divided according to the site of damage into vascular, biliary and extrahepatic complications.

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.

Comparison of Regeneration of Remnant Liver After Hemihepatectomy with or Without the Middle Hepatic Vein

BACKGROUND

There is no consensus about remnant liver regeneration associated with middle hepatic vein (MHV) resecting.

METHODS

Seventy-five patients who underwent hemihepatectomy were retrospectively analysed with respect to remnant liver regeneration. The liver remnant volume (LRV) and each sectional volume were postoperatively measured with multidetector computed tomography at day 7 and months 1, 2, 5, and 12 after the operation.

RESULTS

In right hemihepatectomy cases, the regeneration rate of LRV in the MHV preservation group was significantly higher than that of the MHV resection group at months 5 and 12. In particular, the regeneration rate of remnant segment IV peaked at day 7 and was shrunk after 1 month, and was significant higher in the MHV preservation group. In left hemihepatectomy cases, the regeneration rate of LRV at month 12 was significantly higher in the MHV preservation group. The regeneration rate of the remnant anterior section peaked at 1 month and was shrunk.

CONCLUSION

In this study, the MHV should be preserved or reconstructed whenever possible during hepatic hemihepatectomy. Hepatic regeneration in the MHV perfusion region becomes poor within 7 days to 1 month after surgery (UMIN000023714).

Doppler ultrasound follow-up of middle hepatic vein tributaries-interposition vessel graft in recipients of living donor liver transplantation using modified right lobe grafts

OBJECTIVE

To investigate the value of Doppler ultrasound (US) in recipients of living donor liver transplantation (LDLT) using modified right-lobe grafts (mRLGs) with obstruction of the middle hepatic vein tributaries (MHVTs)-interposition vessel graft (IVG).

METHODS

This study included 240 consecutive LDLT recipients in whom 564 MHVTs (>5 mm) were reconstructed using IVG. Regular follow-up Doppler US was performed to assess the patency of the MHVTs-IVG and, if there was an obstruction, to evaluate for the establishment of collateral drainage. MHVTs with obstruction were subdivided into those with and without intrahepatic veno-venous collaterals on Doppler US and were correlated with CT scans.

RESULTS

MHVTs-IVG obstruction was identified in 137 patients with 227 MHVTs on follow-up Doppler US (6.2  ±  4.7 months). 90 patients with 149 MHVTs in whom the time interval between Doppler US and contrast-enhanced dynamic CT scans was <1 week were classified into either collateral (68 patients with 121 MHVTs) or non-collateral (22 patients with 28 MHVTs) groups. The presence of intrahepatic veno-venous collaterals on Doppler US were significantly related to no remarkable hepatic venous congestion on CT by both per-patient and per-vein analyses (66 of 68 patients (97.1%) and 118 of 121 MHVTs (97.5%), p < 0.001 and p < 0.001, respectively).

CONCLUSION

On Doppler US follow-up of LDLT recipients using mRLGs, identification of intrahepatic veno-venous collaterals associated with obstruction of MHVTs-IVG suggests no remarkable hepatic venous congestion. Advances in knowledge: When an obstruction of a MHVTs-IVG is encountered on Doppler US follow-up of LDLT recipients using mRLGs, no further evaluation with CT is warranted if intrahepatic veno-venous collaterals are observed on Doppler US, as this finding suggests no remarkable hepatic congestion.

Perfusion CT imaging of the liver: review of clinical applications

Perfusion computed tomography (CT) has a great potential for determining hepatic and portal blood flow; it offers the advantages of quantitative determination of lesion hemodynamics, distinguishing malignant and benign processes, as well as providing morphological data. Many studies have reported the use of this method in the assessment of hepatic tumors, hepatic fibrosis associated with chronic liver disease, treatment response following radiotherapy and chemotherapy, and hepatic perfusion changes after radiological or surgical interventions. The main goal of liver perfusion imaging is to improve the accuracy in the characterization of liver disorders. In this study, we reviewed the clinical application of perfusion CT in various hepatic diseases.

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.

Various complications of percutaneous radiofrequency ablation for hepatic tumors: radiologic findings and technical tips

Radiofrequency ablation is a safe and effective treatment for primary and secondary liver malignancies and has a low complication rate; however, there are various radiofrequency ablation-related complications which can occur from the thorax to the pelvis. Although most of these complications are usually minor and self-limited, they may become fatal if diagnosis and treatment are delayed. It is important for radiologists performing radiofrequency ablation to have a perspective regarding the possible radiofrequency ablation-related complications and their risk factors as well as the radiologic findings for their timely detection and increase of the treatment efficacy, and thereby encouraging the use of the radiofrequency ablation technique. This article illustrates the various imaging features of common and rare radiofrequency ablation-related complications as well as offers technical tips in order to avoid these complications.

Hepatic venous congestion in living donor grafts in liver transplantation: is there an effect on hepatocellular carcinoma recurrence?

A certain degree of graft congestion in living donor liver transplantation (LDLT) using a right liver graft may be inevitable because of the mismatch between the inflow and outflow structures of the liver. The subsequent inflammatory reaction and rapid regeneration of the graft have been suggested as causes of tumor recurrence. Therefore, we investigated the influence of graft congestion on hepatocellular carcinoma (HCC) recurrence after LDLT. Two hundred eighty-nine LDLT patients for HCC within the University of California San Francisco criteria between November 1999 and February 2012 were investigated. Patients were assigned to groups on the basis of the degree of congestion (≤10% for group A and >10% for group B), which was determined by 3-dimensional reconstruction of posttransplant multidetector helical computed tomography within 2 weeks. Perioperative characteristics, regeneration rates after 6 months, and recurrence rates were compared between the groups, and a multivariate analysis of the influence of congestion on tumor recurrence was subsequently completed. No significant difference in demographics was found. Group B had more elevated peak posttransplant levels of aspartate aminotransferase (296.26 versus 227.53, P = 0.05), alanine aminotransferase (382.91 versus 276.98, P = 0.04), and highly selective C-reactive protein (5.41 versus 3.55, P < 0.001); a higher noncongestive section regeneration rate (25.8% versus 13.6%, P = 0.012); and a higher recurrence rate (30.4% versus 9.7%, P = 0.01) than group A. Graft congestion > 10% [hazard ratio (HR) = 3.10, 95% confidence interval (CI) = 1.15-8.35, P = 0.03], microvascular invasion (HR = 5.43, 95% CI = 2.04-14.44, P < 0.01), and an alpha-fetoprotein level > 200 IU/L (HR = 2.98, 95% CI = 1.10-8.03, P = 0.03) were significantly related to tumor recurrence. Liver congestion may promote the recurrence of HCC after LDLT; therefore, it should be minimized.

An extended dysfunctional area in the congestive area of the remnant liver after hemi-hepatectomy with middle hepatic vein resection for liver cancers evaluated on the gadoxetic acid disodium-enhanced magnetic resonance imaging

BACKGROUND

The aim of the present study was to evaluate the liver function in the congestive area of the remnant liver after hemi-hepatectomy with middle hepatic vein (MHV) resection for liver cancers.

METHODS

From November 2009 through December 2012, 18 patients underwent hemi-hepatectomy including the MHV for liver cancers. Post-hepatectomy, the volume of the congestive area, which appeared as a hyper-intense area on T2-weighted images and dysfunctional area, which appeared as a low intensity area on hepatobiliary phase images in the remnant liver was evaluated in all patients by gadoxetic acid disodium-enhanced magnetic resonance imaging.

RESULTS

Fifteen of 18 patients showed a congestive area, and 16 of 18 patients showed a dysfunctional area in the remnant liver. The dysfunctional rate (median 11%) was significantly larger than the congestive rate (median 5%, P = 0.0004). The dysfunctional rate was associated with tumor invasion to the root of the MHV, and no tumor invasion to the root of the MHV was identified as a significant predictor of a larger dysfunctional area (odds ratio 25.888, P = 0.0267) on multivariate analysis.

CONCLUSION

Hemi-hepatectomy with MHV resection for liver cancers should be performed considering the dysfunctional area in the remnant liver, which is associated with tumor invasion to the root of the MHV.

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.

Hepatectomy preserving drainage veins of the posterior section for liver malignancy invading the right hepatic vein: an alternative to right hepatectomy

BACKGROUND

Although a right hepatectomy (RH) traditionally has been performed for liver tumors infiltrating the main trunk of the right hepatic vein (RHV), the presence of drainage veins of the posterior section (DVPS) beside the RHV provides a chance to preserve their draining area even if the main trunk of the RHV is removed.

METHODS

Since 2005, we systematically have performed DVPS-preserving hepatectomies whenever possible. In the present study, we describe our experience treating 12 consecutive patients who underwent this procedure.

RESULTS

We performed the following types of liver resections concomitant with the main trunk of the RHV without packed red cell transfusion, liver failure, or 90-day mortality: extended right anterior sectionectomy in 2 patients, extended segmentectomy 7 in 3, extended segmentectomy 8 in 2, and partial resection of segment 7 in 2 and segment 8 in 3. Postoperative morbidity was observed in 4 (33%) cases, all of which had pleural effusion requiring a tap. A free resection margin was obtained in all patients.

CONCLUSIONS

This procedure could be a useful alternative to RH, providing a chance for radical liver resection with minimal parenchymal sacrifice in selected patients with DVPS.

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.

Diffuse liver disease: strategies for hepatic CT and MR imaging

The liver plays several complex but essential roles in the metabolism of amino acids, carbohydrates, and lipids, as well as synthesis of proteins. The basic pathophysiology of diffuse parenchymal hepatic diseases usually represents a failure in one of these metabolic pathways. Specific parenchymal diseases can be categorized as storage, vascular, and inflammatory diseases. Cross-sectional hepatic imaging techniques, specifically multidetector computed tomography (CT) and magnetic resonance (MR) imaging, have roles in evaluation of diffuse liver disease. The prominent role of multidetector CT is primarily defined by its excellent morphologic visualization capabilities, in particular of diffuse or focal intrahepatic lesions as well as of anatomic relationships between the liver and adjacent organs. The variety of available multidetector CT scanners covers a huge spectrum of detector configurations ranging from equally sized and equally spaced detector arrays to asymmetric detector configurations, resulting in imaging protocols with unique parameters for almost each multidetector CT system. In addition to 64-detector row imaging, hepatic multidetector CT can be performed with emerging techniques such as dual-energy CT. Hepatic MR imaging has been proved to be a comprehensive modality for assessing the morphology and functional characteristics of the liver. Concurrent technical improvements as well as implementation of advanced imaging sequence designs permit high-quality examination of the liver with T1-, T2-, and diffusion-weighted pulse sequences. Three basic demands remain if MR imaging is chosen for hepatic imaging: to improve parenchymal contrast, to suppress respiratory motion, and to ensure complete anatomic coverage. Supplemental material available at http://radiographics.rsna.org/content/29/6/1591/suppl/DC1.

Hepatic venous occlusion causes more impairment after reperfusion compared with portal clamping in a murine model

BACKGROUND

Hepatic ischemia/reperfusion (IR) has been extensively studied, but reperfusion after acute hepatic congestion caused by venous occlusion is poorly understood. Congestion/reperfusion (CR) is not uncommon with the development of partial liver transplantation and liver resection. The purpose of this study was to compare the impairments caused by acute hepatic CR or IR using a murine model.

MATERIALS AND METHODS

Mice were randomly divided into IR, CR, and a sham operation (SO) group. The portal vein and hepatic artery of the left anterior hepatic lobe (LAHL) were clamped in the IR group, while the hepatic vein of the LAHL was temporarily occluded in the CR Group. This occurred for 75 min followed by reperfusion. The animals were sacrificed at 2, 6, and 24h after reperfusion. Blood and liver samples were collected for hepatic function, histology, myeloperoxidase (MPO), intravital microscopy, and real-time PCR analysis.

RESULTS

Both IR and CR groups showed elevated liver function, histologic damage, cellular apoptosis, and microcirculatory dysfunction compared with the SO group. Compared with the IR group, the CR group revealed higher hepatic enzyme activities (ALT: 838.5 ± 155.6 versus 474.6 ± 123.8 P<0.05, AST: 792.5 ± 93.5 versus 574.8 ± 188.4 P<0.05), increased sinusoidal nonperfusion rate at 2h after reperfusion (27.4% ± 1.97% versus 23.8% ± 1.93%, P<0.05), and raised MPO level at 24h (0.34 ± 0.11 versus 0.15 ± 0.04, P<0.01). The mRNA levels of IL-1β at 6h and MCP-1 at 2 and 6h were markedly higher in the CR group than in the IR group.

CONCLUSION

Hepatic reperfusion after acute congestion provokes an increased inflammatory response and causes more severe impairments in the liver compared with ischemia/reperfusion in a murine model.

Hepatic outflow obstruction at middle hepatic vein tributaries or inferior right hepatic veins after living donor liver transplantation with modified right lobe graft: comparison of CT and Doppler ultrasound

OBJECTIVE

The objective of our study was to compare CT and Doppler ultrasound in the diagnosis of hepatic outflow obstruction at the middle hepatic vein (MHV) tributaries and inferior right hepatic veins (RHVs) after living donor liver transplantation (LDLT) with modified right lobe grafts.

MATERIALS AND METHODS

Thirty-seven venographies were performed in 36 patients after LDLT with modified right lobe grafts, evaluating 51 MHV tributaries and 25 inferior RHVs. They were classified as obstructed or nonobstructed. On Doppler ultrasound or CT, flow patterns of the MHV tributaries and inferior RHVs or the relative parenchymal attenuation, enhancement, and opacification of these veins were evaluated for the diagnosis of hepatic outflow obstruction. McNemar tests were performed to compare the diagnostic values of Doppler ultrasound and CT.

RESULTS

On the basis of hepatic venography, 33 MHV tributaries were categorized as obstructed and 18 as nonobstructed, and 16 inferior RHVs were categorized as obstructed and nine as nonobstructed. For the diagnosis of MHV tributary obstruction, Doppler ultrasound was more sensitive and accurate, although less specific, than CT (97% vs 39%, respectively, p < 0.001; 86% vs 61%, p = 0.0209; 67% vs 100%, p = 0.0412). Similarly, Doppler ultrasound was more sensitive (94% vs 31%, respectively) and accurate (84% vs 56%) than CT, although less specific (67% vs 100%), for the diagnosis of inferior RHV obstruction, with a statistical significance only for sensitivity (p = 0.002, 0.092, and 0.248, respectively).

CONCLUSION

Doppler ultrasound is more sensitive and accurate than CT for the detection of obstruction at the MHV tributaries and inferior RHVs in patients after LDLT using modified right lobe grafts. Although current CT criteria produce high specificity and may reduce unnecessary invasive venographies, optimal CT criteria with acceptable sensitivity should be reestablished.

Uncommon causes of hepatic congestion in patients after living donor liver transplantation

OBJECTIVE

The purpose of this article is to illustrate the radiologic findings of various uncommon conditions that cause hepatic congestion in patients after living donor liver transplantation.

CONCLUSION

Radiologic findings of hepatic congestion may vary according to the cause and the level of outflow obstruction. It is important for radiologists to be aware of such variations in order to make an early diagnosis of hepatic congestion and to enable timely proper management in recipients after living donor liver transplantation.

Evaluation of standard liver volume formulae for Chinese adults

AIM: To evaluate different standard liver volume (SLV) formula and verify the applicability of the formulae for Chinese adults.

METHODS: Data from 70 cases of living donor liver transplantation (LDLT) performed at our transplantation centers between January 2008 and April 2009 were analyzed. SLV was estimated using our recently reported formula [the Chengdu formula: SLV (mL) = 11.5 × body weight (kg) + 334] and other reported formulae used for Chinese adults. Actual intraoperative liver volumes were obtained from a review of the patients’ medical records.

RESULTS: The actual right liver volume was not significantly different from the estimated right liver volume determined by the Chengdu formula, but was significantly smaller than estimates using the Heinemann, Urata, Vauthey, and Lee formulae (P < 0.01), and significantly larger than estimates using the Fan formula (P < 0.05).

CONCLUSION: The Chengdu formula was demonstrated to be reliable by its application in LDLT.

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.

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.

Advances in imaging diagnosis of Budd-Chiari syndrome

Budd-Chiari syndrome (BCS) is very easy to be misdiagnosed due to the lack of specificity in clinical manifestation. With the improvement of multiple imaging diagnostic devices and methods, the detection rate of BCS is raised. The noninvasive imaging examination methods, such as ultrasound, multi-slice computed tomography (MSCT), magnetic resonance imaging (MRI), are able to clearly display hepatic vein (HV), inferior vena cave (IVC), and the location and type of stenosis. Therefore, they are useful for the clinical treatment and result observation.

Value of CT and Doppler Sonography in the Evaluation of Hepatic Vein Stenosis After Dual-Graft Living Donor Liver Transplantation

OBJECTIVE

The purpose of this study was to evaluate the imaging findings and role of CT and Doppler sonography in the diagnosis of hepatic vein (HV) stenosis after dual-graft living donor liver transplantation (LDLT).

MATERIALS AND METHODS

Using hepatic venography as the reference standard, 73 grafts with venographic evaluation in 43 dual-graft LDLT recipients were classified into either a stenosis (n = 39) or a nonstenosis (n = 34) group. CT scans were evaluated for relative attenuation, enhancement pattern, and HV abnormality for each graft. Doppler sonography evaluation of the flow pattern of HVs for each graft was performed. CT and Doppler sonography findings were compared in the stenosis and nonstenosis groups using the independent sample Student's t test and Fisher's exact test. Multifactorial logistic regression analysis was performed to determine the best predictors of the diagnosis of HV stenosis.

RESULTS

Heterogeneous enhancement (p = 0.046), abnormal HV on CT (p = 0.025), and HV wave pattern on Doppler sonography (p = 0.005) were significant findings. The accuracy for the diagnosis of HV stenosis was 60.0% for heterogeneous enhancement, 61.5% for abnormal HV, and 66.2% for a monophasic flow pattern. Heterogeneous enhancement and HV wave pattern were significant independent findings on multifactorial logistic regression analysis. The overall accuracy of the logistic model in the diagnosis of HV stenosis was 71.7%.

CONCLUSION

Although CT and Doppler sonography can be helpful in diagnosing HV stenosis, given the low accuracy of individual imaging findings, the diagnosis of HV stenosis should be made cautiously, with both CT and Doppler sonography regarded as complementary examinations.

Adult living donor liver transplantation: living donation of the right liver lobe

BACKGROUND

Adult living donor liver transplantation (LDLT) has become a routine treatment option for patients waiting for liver transplantation. In European and North American countries, LDLT for adult recipients is mainly performed with right lobe grafts. Indications, when compared to deceased donor liver transplantation, are controversial.

MATERIALS AND METHODS

In our institution, patients suffering from hepatocellular carcinoma in cirrhosis, non-resectable hilar cholangiocarcinoma, viral hepatitis associated cirrhosis, as well as cholestatic liver and biliary disease are considered good candidates for LDLT.

RESULTS

In this overview, donor evaluation, graft selection, and the donor operation with special regard to operative techniques and strategies are discussed. For visualization, a 5-min video sequence of the standard donor operation as performed in our institution is attached.

CONCLUSION

Given the ongoing shortage of donor organs, adult LDLT has become a routine treatment option for patients waiting for liver transplantation. The associated inevitable risk for the healthy donor, however, remains ethically controversial.

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.

Live donor liver transplantation in adults

Live donor liver transplantation (LDLT) was initiated in 1988 for children recipients. Its application to adult recipients was limited by graft size until the first right liver LDLT was performed in Hong Kong in 1996. Since then, right liver graft has become the major graft type. Despite rapid adoption of LDLT by many centers, many controversies on donor selection, indications, techniques, and ethics exist. With the recent known 11 donor deaths around the world, transplant surgeons are even more cautious than the past in the evaluation and selection of donors. The need for routine liver biopsy in donor evaluation is arguable but more and more centers opt for a policy of liberal liver biopsy. Donation of the middle hepatic vein (MHV) in the right liver graft was considered unsafe but now data indicate that the outcome of donors with or without MHV donation is about equal. Right liver LDLT has been shown to improve the overall survival rate of patients with chronic liver disease, acute or acute-on-chronic liver failure and hepatocellular carcinoma waiting for liver transplantation. The outcome of LDLT is equivalent to deceased donor liver transplantation despite a smaller graft size and higher technical complexity.

Complications of percutaneous radiofrequency ablation for hepato-cellular carcinoma: imaging spectrum and management

Percutaneous radiofrequency (RF) ablation is feasible for the treatment of unresectable hepatocellular carcinoma, and experience at the authors' institution during 5 years indicates that percutaneous RF ablation can be performed safely in most cases. However, early or late complications related to mechanical or thermal damage may be observed at follow-up examination. Complications may be classified in three groups: vascular (eg, portal vein thrombosis, hepatic vein thrombosis with partial hepatic congestion, hepatic infarction, and subcapsular hematoma), biliary (eg, bile duct stenosis and biloma, abscess, and hemobilia), and extrahepatic (eg, injury to the gastrointestinal tract, injury to the gallbladder, pneumothorax and hemothorax, and tumor seeding). Most complications can be managed with conservative treatment, percutaneous or endoscopic drainage, or surgical repair. Because an early and accurate diagnosis is necessary for proper management, radiologists should be familiar with the imaging features of each type of complication.

Endovascular stent placement for interposed middle hepatic vein graft occlusion after living-donor liver transplantation using right-lobe graft

Middle hepatic vein (MHV) reconstruction is performed to drain the right paramedian sector to prevent hepatic venous congestion (HVC). The aim of the present study was to evaluate endovascular stent placement in patients with stenosed and/or occluded interposition vein graft (IVG) to segment V hepatic vein (V5) and segment VIII hepatic vein (V8) after living-donor liver transplantation (LDLT). The procedure was performed in 11 recipients; 7 underwent it within 24 hours of LDLT. The following parameters, including technical success, clinical success, complications, patient survival data, and serial computed tomography (CT) findings during follow-up, were documented retrospectively. Technical success was defined as both successful stent placement and resolution of stenosis or occlusion with copious flow of contrast medium through the stent, while clinical success was defined as both improvement of liver function tests (LFTs) and reduction or disappearance of hepatic low-attenuation areas on follow-up CT scans taken within 1 week of stent placement. Technical success was achieved in 10 of 11 patients (91%), and clinical success was achieved in 9 of 11 patients (82%). Acute thrombotic occlusion of the stent-inserted hepatic vein occurred in 1 patient 1 day following stent placement. During the mean follow-up period of 468 days (range, 13-891 days), 9 patients survived and 2 patients died. No death was directly related to stent placement or its related complications. The low-attenuation area in the involved hepatic segment V (S5) and/or VIII (S8) area prior to stent placement disappeared completely on follow-up CT scans performed at 3-12 days (mean, 5.4 days) after stent placement in all 9 patients with clinical success. No attenuation change occurred even in cases with chronic occlusion of the stent-inserted hepatic veins. In conclusion, though IVG to V5 and V8 remains controversial, the treatment of their stenosis or occlusion is safe and effective, even during their immediate postoperative period.

Living donor liver transplantation

The introduction of living donor liver transplantation (LDLT) has been one of the most remarkable steps in the field of liver transplantation (LT). First introduced for children in 1989, its adoption for adults has followed only 10 years later. As the demand for LT continues to increase, LDLT provides life-saving therapy for many patients who would otherwise die awaiting a cadaveric organ. In recent years, LDLT has been shown to be a clinically safe addition to deceased donor liver transplantation (DDLT) and has been able to significantly extend the scarce donor pool. As long as the donor shortage continues to increase, LDLT will play an important role in the future of LT.

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.