Detachable balloon-modified reducing stent to treat hepatic insufficiency after transjugular intrahepatic portosystemic shunt creation

A patient developed severe hepatic insufficiency after creation of a transjugular intrahepatic portosystemic shunt, which was treated unsuccessfully with a constrained Wallstent ("reducing stent"). After a failed attempt at occluding the shunt with an occlusion balloon, a detachable balloon was placed at the portal end of the constrained stent. This balloon-modified reducing stent reduced flow while maintaining shunt patency, and the patient's hepatic insufficiency improved. She went on to undergo successful liver transplantation several months later.

Efficacy of an extracorporeal flat-plate bioartificial liver in treating fulminant hepatic failure

BACKGROUND

Fulminant hepatic failure is associated with a high mortality rate. Orthotopic liver transplantation is the only established treatment for patients who do not respond to medical management. A major limitation of this treatment is a shortage of donor organs, resulting in many patients dying while waiting for a transplant. An extracorporeal bioartificial liver (BAL) has the potential to provide temporary support for patients with fulminant hepatic failure (FHF) and for patients awaiting orthotopic liver transplantation. We developed a flat-plate BAL with an internal membrane oxygenator in which porcine hepatocytes were cultured as a monolayer.

MATERIALS AND METHODS

Twenty-four hours after cannulation of the left carotid artery and right jugular vein, FHF was induced in rats by administering 2 intraperitoneal injections of D-galactosamine (GalN) (1.2 g/kg) at a 12-h interval. The rats were connected to a BAL device 24 h after the first GalN injection and underwent extracorporeal perfusion for a duration of 10 h. Liver histology, liver-specific markers, and animal survival up to 168 h (7 days) were examined.

RESULTS

Histologically, liver damage was reduced in the animal group treated with the hepatocyte-based BAL device. Significant reductions occurred in the plasma ammonia levels and prothrombin times in the group treated with the seeded BAL device. Animal survival in the group treated with the seeded BAL device was significantly higher (50.0%) than in the control animal group treated with an unseeded BAL device (11.1%).

CONCLUSIONS

This flat-plate BAL with an internal membrane oxygenator and cultured porcine hepatocytes has yielded encouraging results in the treatment of rats with GalN-induced FHF.

Hepatocyte growth factor gene therapy accelerates regeneration in cirrhotic mouse livers after hepatectomy

BACKGROUND

Impaired regeneration and dysfunction of the cirrhotic liver following partial hepatectomy (PHx) are the most serious risk factors for postoperative liver failure.

AIMS

Using naked hepatocyte growth factor (HGF) plasmid by the electroporation (EP) in vivo method, we investigated HGF for its role and mechanism of proliferation and restoration of liver mass in cirrhotic mice following PHx.

ANIMALS

Eight week old female mice were used.

METHODS

HGF plasmid 50 micro g was injected intramuscularly and transferred by EP in vivo once a week for three weeks. After establishment of carbon tetrachloride induced cirrhosis, mice underwent PHx. The HGF treated group was given naked HGF plasmid four days before PHx, and additional HGF was given once a week until they were killed, while a control group was given only empty plasmid. Mice were killed 2, 4, 10, and 14 days after PHx. Morphological and functional restoration of the liver were examined, as well as activation of mitogen activated protein kinase (MAPK) and mRNA levels of HGF activator (HGFA).

RESULTS

The HGF treated group demonstrated a continuous threefold increase in HGF levels in plasma. Therapy with HGF in cirrhotic PHx resulted in effective liver regeneration via restoration of HGFA and activation of MAPK p44/p42, accelerated normalisation of liver function, and increased collagen degradation.

CONCLUSIONS

HGF gene therapy by in vivo EP may be useful for hepatic resection in cirrhotic livers by stimulating liver proliferative and collagenolytic capacities, as well as accelerating functional recovery.

Overexpression of thioredoxin prevents acute hepatitis caused by thioacetamide or lipopolysaccharide in mice

Thioredoxin (Trx) is a small redox-active protein with antioxidant and antiapoptotic effects. Trx transgenic (Tg) mice are more resistant to cerebral infarction and survive longer than wild-type (WT) C57BL/6 mice. The aim of the present study was to investigate the protective role of Trx in acute hepatitis models. The expression of endogenous Trx was decreased in thioacetamide (TAA)-induced acute hepatitis. TAA (100 microg/g) was injected intraperitoneally in WT and Tg mice. Survival rate after TAA injection was higher in Tg mice than in WT mice. The level of oxidative stress was significantly less in Tg mice than in WT mice, as shown by the protein carbonylation assay and lipid peroxidation assay. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cells were less in Tg mice than in WT mice, which was consistent with DNA laddering assay. Caspase-3 and caspase-9 activities and cytochrome c release were significantly inhibited in Tg mice compared with those in WT mice. In addition, lipopolysaccharide (LPS) plus d-galactosamine (GalN), or anti-Fas antibody (Jo2) were injected. Survival rate after LPS plus GalN injection was much higher in Tg mice than in WT mice. In contrast, there was no difference in survival rate after Jo2 injection between WT and Tg mice. In conclusion, transgene of Trx attenuated TAA- or LPS-induced acute lethal hepatitis. In addition to an antioxidant effect, Trx has the potential to protect acute liver injury via an antiapoptotic effect, which mainly inhibits mitochondria-mediated apoptosis signaling.

Auxiliary partial liver grafting in rats: effect of host hepatectomy on graft regeneration, and review of literature on surgical technique

Auxiliary partial liver transplantation (APLT) is beneficial for fulminant liver failure when there is potential for recovery of the diseased liver. However, the impact of host hepatectomy on regeneration of the grafted liver is unclear. In this study, we modified a previous rat model of auxiliary whole liver transplantation without portal vein reconstruction, and studied the effect of host hepatectomy on regeneration of the cut liver graft. Thirty percent of the liver was heterotopically transplanted, to connect the recipient's left renal artery and vein with the graft's aortic cuff of the hepatic artery and inferior vena cava, respectively, using a cuff technique; 30% of the recipient liver then was cut. The control group was left intact. The liver grafts were weighed preoperatively and 2 weeks postoperatively. This procedure prevented congestion of the graft liver and achieved a high success rate, even when performed by a surgeon who was relatively inexperienced with the technique. The weight of the grafted liver in the host hepatectomized group significantly increased (P < 0.05) compared with that of the control group. We developed an experimental model of APLT and reviewed the literature on rat heterotopic liver transplantation, and compared the surgical techniques.

Fulminant hepatic failure

The term "fulminant hepatic failure" (FHF) encompasses a pattern of clinical symptoms and pathophysiological responses associated with rapid arrest of normal hepatic function. The syndrome is defined by the presence of hepatic encephalopathy in association with coagulopathy and jaundice. In many cases, the clinical picture is complicated by cerebral edema, renal impairment, sepsis, and multiorgan failure. In this review, we examine the specific causes of FHF, including acetaminophen-related hepatotoxicity, drug- and viral-related FHF, and other less common causes of FHF such as pregnancy and vascular related disease. The approach to FHF should be multidisciplinary and requires a thorough understanding of the biochemical, metabolic, and physiological changes associated with hepatic necrosis. Also examined are management issues pertinent to these complex situations and the role of liver transplantation and liver assist devices are considered.

Body composition and components of energy expenditure in children with end-stage liver disease

BACKGROUND

Better understanding of body composition and energy metabolism in pediatric liver disease may provide a scientific basis for improved medical therapy aimed at achieving optimal nutrition, slowing progression to end-stage liver disease (ESLD), and improving the outcome of liver transplantation.

METHODS

Twenty-one children less than 2 years of age with ESLD awaiting liver transplantation and 15 healthy, aged-matched controls had body compartment analysis using a four compartment model (body cell mass, fat mass, extracellular water, and extracellular solids). Subjects also had measurements of resting energy expenditure (REE) and respiratory quotient (RQ) by indirect calorimetry. Nine patients and 15 control subjects also had measurements of total energy expenditure (TEE) using doubly labelled water.

RESULTS

Mean weights and heights were similar in the two groups. Compared with control subjects, children with ESLD had higher relative mean body cell mass (33 +/- 2% vs 29 +/- 1% of body weight, P < 0.05), but had similar fat mass, extracellular water, and extracellular solid compartments (18% vs 20%, 41% vs 38%, and 7% vs 13% of body weight respectively). Compared with control subjects, children with ESLD had 27% higher mean REE/body weight (0.285 +/- 0.013 vs 0.218. +/- 0.013 mJ/kg/24h, P < 0.001), 16% higher REE/unit cell mass (P < 0.05); and lower mean RQ (P < 0.05). Mean TEE of patients was 4.70 +/- 0.49 mJ/24h vs 3.19 +/- 0.76 in controls, (P < 0.01).

CONCLUSIONS

In children, ESLD is a hypermetabolic state adversely affecting the relationship between metabolic and nonmetabolic body compartments. There is increased metabolic activity within the body cell mass with excess lipid oxidation during fasting and at rest. These findings have implications for the design of appropriate nutritional therapy.

Treatment of life-threatening hyperkalemia using hemoconcentration in parallel to venovenous bypass during orthotopic liver transplantation

IMPLICATIONS

The elimination of potassium in patients with end-stage kidney failure is limited. An increase in potassium concentrations can lead to lethal arrhythmias. In the described case, a large potassium concentration was treated during a liver transplantation using a new technical approach.

A correlation between the pretransplantation MELD score and mortality in the first two years after liver transplantation

The Model for End-Stage Liver Disease (MELD) score is now the criteria for allocation in liver transplantation for patients with chronic disease. Although the score has been effective in the prediction of mortality in patients awaiting liver transplantation, its abilities to predict posttransplantation outcome need study. The aim of this study is to compare outcome in the first 2 years after liver transplantation according to the pretransplantation MELD score. The study includes 669 consecutive patients who underwent primary liver transplantation between December 1993 and October 1999 in a single transplant center. Patients who died of malignancy were excluded from the series. Pretransplantation MELD score was calculated using the United Network for Organ Sharing formula. Patients were stratified according to MELD score less than 15, 15 to 24, and 25 and higher. Posttransplantation survival at 3, 6, 12, 18, and 24 months was significantly lower in the groups with a higher MELD score. The difference was significant for hepatitis C and noncholestatic liver diseases, but not cholestatic diseases. In patients with a MELD score between 15 and 24, survival was significantly greater with cholestatic diseases and lower in patients with hepatitis C. In our study, pretransplantation MELD score correlates with survival in the first 2 years after transplantation. There is a survival advantage for patients with cholestatic diseases compared with those with hepatitis C. These findings suggest the need to readjust MELD score-based allocation decisions to consider patient outcome.

Advances in extracorporeal detoxification by MARS dialysis in patients with liver failure

Although liver transplantation has become standard procedure for patients with liver failure, a number of issues in the management of these patients remains to be addressed. Alternative approaches have been tested, such as hepatocytes containing liver-support systems and filtration devices. However, the replacement of detoxification has been difficult, as the majority of toxins accumulating in liver failure is albumin-bound. Albumin dialysis (MARS system) is characterized by the specific removal of albumin-bound toxins through an innovative membrane transport. In particular, the albumin acts as a specific molecular adsorbent that is regenerated on line in a recycling system. Nowadays MARS represents the most frequently used liver support system. This treatment has been shown to remove albumin-bound molecules, such as bilirubin, bile acids, aromatic amino acids and copper. The removal of these toxins is clinically accompanied with an improvement of liver, cardiovascular and renal functions and hepatic encephalopathy. In several trials MARS was found to improve the clinical situation in patients with acute exacerbation of chronic liver failure and acute hepatic failure, but also in hepatorenal syndrome and primary graft non function or chronic rejection after liver transplantation. In summary, a critical analysis of the literature confirms that MARS device can be a safe therapeutic choice to achieve a better clinical outcome, and, sometimes, a survival advantage in patients with liver failure, even if a multi-center randomized trial is the only reliable way to enforce today's results. Further advances in the MARS components will definitively state whether albumin dialysis may represent the future in the field of artificial liver devices.

Cyclooxygenase-2 and inducible nitric oxide synthase in omental arteries harvested from patients with severe liver diseases: immuno-localization and influence on vascular tone

OBJECTIVE

To investigate the expression of inducible cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) and the role of vasodilatory prostanoids and endogenous nitric oxide (NO) in small omental arteries harvested from patients with severe liver diseases.

DESIGN

Ex vivo study of resistance arteries. SETTING. Intensive care unit.

PATIENTS

Twenty patients undergoing liver transplantation for fulminant hepatic failure (FHF, n=6), cirrhogenous viral hepatitis (CH, n=6) and limited hepatocarcinoma (controls, n=8).

INTERVENTIONS

Western blot and immunohistochemical labeling for assessment of COX-2 and iNOS expression and localization and ex vivo vascular reactivity studies.

MEASUREMENTS AND RESULTS

Significant upregulation of COX-2 and iNOS expressions were detected in arteries from FHF and CH patients with a greater increase in the former than in the latter. Ex vivo contractile responses to norepinephrine and the thromboxane A(2) analog, U46619, were not significantly different between patients with severe liver dysfunction and controls. Exposure to either the NO-synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), the cyclooxygenase inhibitor, indomethacin, or their combination did not significantly modify contractions of agonists in controls and CH patients. In FHF, the specific COX-2 inhibitor, N-(2-cyclohexyloxy-4-nitrophenyl) methanesulfonamide (1 micro m/l), but not L-NAME, significantly enhanced the maximal effect ( p<0.01) and the sensitivity ( p<0.01) to norepinephrine.

CONCLUSIONS

COX-2 and iNOS are upregulated in omental arteries from patients with cirrhogenous hepatitis and fulminant hepatic failure. Whereas neither NO nor vasodilatory prostaglandins seem to play a major role in counteracting arterial contractility of arteries from control patients, COX-2 derivatives are involved in lowering the arterial contractility of vessels harvested from FHF patients.

Cerebral oxygenation determined by near-infrared spectrophotometry in patients with fulminant hepatic failure

BACKGROUND/AIMS

In severe cases of acute liver failure (ALF), cerebral hyperperfusion may result in high intracranial pressure and brain damage. The aim of this study was to determine if near-infrared spectrophotometry (NIRS) could detect a raise in cerebral blood flow and oxygenation induced by noradrenaline (NA) infusion.

METHODS

In seven ALF patients (five females and two males; median age 49 years (range 20-70)) changes in cerebral concentration of oxy-(deltaHbO(2)) and total-haemoglobin (deltaHbT) were compared to the jugular bulb saturation (SvjO(2)) and cerebral blood flow velocity (Vmean) during NA infusion.

RESULTS

Mean arterial pressure increased from 68 (64-86) to 103 (87-118) mmHg and the cerebral perfusion pressure from 61 (53-79) to 95 (74-110) mmHg (P<0.05), while the intracranial pressure (7 (6-15) mmHg) was not significantly changed. In six patients cerebral deltaHbO(2) and deltaHbT increased 2.7 (0.3-9.6) and 2.0 (0.3-14.8) micromol l(-1), respectively, but cerebral oxygenation decreased in one patient. SvjO(2) increased from 68 (55-76) to 74 (64-78) % (P<0.05) concomitant with an increase in Vmean from 47 (34-65) to 68 (50-86) cm s(-1) (P<0.05). deltaHbO(2) covariated with changes in SvjO(2) during NA in all but one patient.

CONCLUSIONS

In ALF patients, a change in cerebral perfusion was detected by NIRS. The combination of NIRS and transcranial Doppler sonography may be valuable non-invasive techniques to detect cerebral hyperperfusion before intracranial hypertension becomes manifest.

Mechanism of postoperative liver failure after excessive hepatectomy investigated using a cDNA microarray

BACKGROUND/PURPOSE

Excessive hepatectomy often causes fatal liver failure. We have reported that this is mainly mediated by apoptosis, characterized pathologically by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) assay-positive hepatocytes and a ladder pattern in DNA fragmentation assays.

METHODS

To investigate the mechanism, we used cDNA microarray analysis to compare clearly differentiated rat partial hepatectomy (PHx) models (90% PHx, and 95% PHx). All 90% PHx rats survived, but the 95% PHx animals died of hepatic failure within 96 h. Remnant liver was obtained at four time points (1, 3, 12, and 24 h after PHx). After RNA extraction, two samples were labeled with different fluorescent dyes and hybridized to the Institute of Physical and Chemical Research (RIKEN) set of 18 816 full-length enriched mouse cDNA arrays. Scanning for fluorescent dye signals was performed, and the mRNA expression ratio of the two models was examined.

RESULTS

Genes of the p21 cyclin-dependent kinase (CDK) inhibitor, Fas, interleukin (IL)-18, and many caspases were upregulated at 1 h after PHx in the 95% PHx group. On the other hand, genes of Bcl-2, heat shock proteins, and glutathione-S-transferase were downregulated.

CONCLUSIONS

We concluded that fatal hepatic failure after excessive hepatectomy was characterized by increased apoptosis and diminished liver regeneration.

Dominant negative MORT1/FADD rescues mice from CD95 and TNF-induced liver failure

Derangement of the apoptotic program is considered an important cause of liver disease. It became clear that receptor-mediated apoptosis is of specific interest in this context, and CD95 and CD120a, both members of the tumor necrosis factor (TNF) receptor superfamily, are the most prominent cell death receptors involved. The death signal is induced upon ligand binding by recruitment of caspases via the adapter molecule MORT1/FADD to the receptor and their subsequent activation. To investigate the role of MORT1/FADD in hepatocyte apoptosis, we generated transgenic mice expressing liver-specific dominant negative mutant. Mice looked grossly normal; breeding and liver development were not different compared with wild-type littermates. Expression of the transgene completely protected animals from liver failure induced by the anti-Fas antibody Jo2, whereas control animals died as expected 3 to 6 hours after i.p. injection of 15 microg antibody from acute hemorrhagic liver failure. Histology demonstrated only moderate inflammatory changes in the transgenic animals, whereas severe hemorrhagic hepatitis was observed in controls. Similar results were obtained in a model of TNF-mediated liver failure, in which transgenic animals survived significantly better than wild-type animals. In conclusion, our experiments provide evidence that MORT1/FADD is indispensable for Fas and TNF-mediated hepatic injury. This is not only of great importance for targeting future therapies for liver disease but might also serve as an intriguing model to study other causes of liver injury.

Portal embolization in various types of liver: novel variables to predict hypertrophy

BACKGROUND/AIMS

The aim of this study was to investigate the hypertrophic effect of portal embolization in various types of liver and clarify useful variables, for predicting efficacy of portal embolization.

METHODOLOGY

Portal embolization was performed for 46 patients with hepatocellular carcinoma (n = 30), biliary tract cancer (n = 9), or metastatic liver tumors (n = 7). The hypertrophic effect of portal embolization in relation to diseases, clinical liver conditions, histological fibrosis, and liver function were examined.

RESULTS

The hypertrophic effect of portal embolization was impaired in the patients with hepatocellular carcinoma, chronic hepatitis/cirrhotic liver, and advanced liver fibrosis. ICGR15 (indocyanine green dye retention rate at 15 minutes) was revealed to be an independent adverse predicting factor. Especially in hepatocellular carcinoma patients, platelet count was significantly correlated with the hypertrophy ratio. In patients who underwent major hepatectomy for hepatocellular carcinoma, not only the incidences of posthepatectomy liver failure but also survival rate were similar between patients with and without portal embolization, although patients with portal embolization originally had a limited liver function.

CONCLUSIONS

Preoperative portal embolization made major hepatectomy possible in hepatocellular carcinoma patients, although portal embolization was less effective compared with other diseases. ICGR15 and platelet count may be novel variables to predict the hypertrophic effect of portal embolization in all and hepatocellular carcinoma patients, respectively.

Liver and kidney function and histology in rats exposed to cadmium and ethanol

AIMS

The present study was performed to assess the function and histology of the liver and kidney in rats exposed to 50 mg Cd/l (as cadmium chloride) and/or 10% (w/v) ethanol (EtOH) for 12 weeks.

METHODS

The activities of alanine aminotransferase (ALAT) and asparate aminotransferase (AspAT) in serum were measured as indicators of the liver function. As parameters of the kidney function, creatinine, total protein and urea concentrations in serum and urine, as well as urinary alkaline phosphatase (ALP) activity were determined, and creatinine clearance was calculated. Both organs were subjected to histopathological analysis.

RESULTS

Daily Cd intake ranged from 3.17 to 4.28 mg/kg body weight and from 2.41 to 3.17 mg/kg body weight in the Cd and Cd + EtOH groups, respectively. The daily intake of 10% EtOH ranged from 47.5 to 86.9 g/kg body weight in the EtOH and from 47.3 to 63.4 g/kg body weight in the Cd + EtOH-exposed rats. Cd and EtOH, independently of separate or combined application, changed liver and kidney function and histology. Rats treated with Cd alone and those co-exposed to both substances showed qualitatively similar, but different magnitudes of changes, in liver and kidney histology. Blurred trabecular structure, vacuolar degeneration and increased density of nuclear chromatin with very compact nuclear structure were found in hepatocytes of zones 2 and 3. Moreover, mononuclear cell infiltrations and necrosis of single cells were evident in zone 1. In the kidney tubules, degeneration and hypertrophy of epithelial cells and dilation in the glomeruli were also observed. Some functional (increased serum AspAT and urinary ALP, decreased urinary urea) and structural changes in the liver and kidney were more evident in the case of combined exposure, while others were more evident after single exposure. However, a decrease in creatinine clearance, noted only in the animals treated with Cd and EtOH, shows that functional changes indicating renal insufficiency are more serious in the co-exposed group.

CONCLUSIONS

Due to lower Cd and EtOH intake (resulting from a stronger aversion to drinking water containing both substances) in the co-exposed rats, as compared to the Cd- and EtOH-treated groups, it is difficult to draw a definite conclusion from this study. The findings, however, seem to indicate that EtOH increases Cd nephrotoxicity in rats, and thus may suggest a higher risk of kidney damage in alcoholics exposed to Cd. Unfortunately, this study does not provide clear evidence if, and to what extent, EtOH influences Cd hepatotoxicity.

Effects of hyperammonemia and liver failure on glutamatergic neurotransmission

Glutamate is the main excitatory neurotransmitter in mammals. Glutamatergic neurotransmission involves several steps, beginning with release of glutamate from the presynaptic neuron. Glutamate in the extracellular space activates glutamate receptors present in the synaptic membranes, leading to activation of signal transduction pathways associated with these receptors. To avoid continuous activation of glutamate receptors, glutamate is removed from the synaptic cleft by specific glutamate transporters located mainly on astrocytes. All these steps are tightly modulated under physiological conditions, and alterations of any of the above steps may result in impairment of glutamatergic neurotransmission, leading to neurological alterations. There are studies in the literature reporting alterations in all these steps in hyperammonemia and/or hepatic failure. Glutamatergic neurotransmission modulates important cerebral processes. Some of these processes are altered in patients with liver disease and hepatic encephalopathy, who show altered sleep-wake patterns, neuromuscular coordination, and decreased intellectual capacity. The alterations in glutamatergic neurotransmission may be responsible for some of these neurological alterations found in hepatic encephalopathy. The effects of hyperammonemia and liver failure on different steps of glutamatergic neurotransmission including alterations of glutamate concentration in the extracellular fluid in brain, transport and transporters of glutamate, the content and function of different types of glutamate receptors and signal transduction pathways. Alterations induced by hyperammonemia and liver failure on the glutamate-nitric oxide-cGMP pathway in brain may result in changes in long-term potetiation and learning ability.

Caspofungin

Available systemically effective antifungal agents for the treatment of invasive fungal infections are few. With the increasing recognition of a need for newer antifungal drugs, caspofungin has been introduced as the first member of a new class of compounds called echinocandins. This paper reviews the chemistry and mechanism of action of caspofungin, its activity in vitro and in animal models, and clinical pharmacokinetics,clinical efficacy and safety in patients.

Magnetic resonance imaging measurement of brain edema in patients with liver disease: resolution after transplantation

PURPOSE OF REVIEW

Results from experimental studies indicate that widespread osmotic disturbance induced by astrocytic accumulation of glutamine as a result of ammonia detoxification may lead to brain edema, not only in cases of fulminant hepatic failure, but in the entire spectrum of liver disease. This review summarizes recent magnetic resonance imaging data obtained in patients with chronic liver failure before and after liver transplantation that support the hypothesis that mild brain edema exists in these patients in the absence of clinical hepatic encephalopathy.

RECENT FINDINGS

Diffuse white matter abnormalities have been detected with several magnetic resonance imaging techniques such as magnetization transfer ratio measurements, which show significantly low values in otherwise normal appearing brain white matter, and fast-Flair sequences, which show abnormal high-signal intensity of the hemispheric white matter tracts. Both these abnormalities return to normal with restoration of liver function, indicating their reversibility and supporting the hypothesis that they reflect mild diffuse brain edema.

SUMMARY

It is likely that magnetic resonance imaging will be increasingly used to evaluate the mechanisms involved in the pathogenesis of hepatic encephalopathy and to assess the effects of therapeutic measures focused on correcting astrocyte swelling in these patients.