With the increased temporal resolution available in dynamic computed tomography (CT) and magnetic resonance imaging (MRI), hepatic arterioportal shunts are now more frequently encountered than in the past. The condition occurs in various hepatic diseases in which portal or hepatic venous flow is compromised. The underlying mechanism and the degree of shunt affect its appearance at dynamic imaging. The dynamic CT and MRI findings have been summarized as early enhancement of peripheral portal veins, and wedge-shaped transient parenchymal enhancement during the hepatic arterial phase. Recognition of arterioportal shunt can suggest the presence of a previously unsuspected disorder and avoids false-positive diagnosis or overestimation of a hepatic disease. Familiarity with the pathophysiology of arterioportal shunt also allows investigation of the hepatic hemodynamic changes occurring in various hepatic diseases.
Computed tomography (CT); Computed tomography (CT), helical; Liver, CT; Liver, MR; Magnetic resonance (MR), rapid imaging; Shunts, arteriovenous
A congenital intrahepatic portosystemic shunt is a rare anomaly; but, the number of diagnosed cases has increased with advanced imaging tools. Symptomatic portosystemic shunts, especially those that include hyperammonemia, should be treated; and various endovascular treatment methods other than surgery have been reported. Hepatic masses with either an intra- or extrahepatic shunt also have been reported, and the mass is another reason for treatment. Authors report a case of a congenital intrahepatic portosystemic shunt with a hepatic mass that was successfully treated using a percutaneous endovascular approach with vascular plugs. By the time the first short-term follow-up was conducted, the hepatic mass had disappeared.
Portosystemic shunt, surgical; Liver neoplasm; Radiology, interventional
Purpose. Review the safety and long-term success with portosystemic shunts in children at a single institution. Methods. An IRB-approved, retrospective chart review of all children ages 19 and undergoing surgical portosystemic shunt from January 1990–September 2008. Results. Ten patients were identified, 8 females and 2 males, with a mean age of 15 years (range 5–19 years). Primary diagnoses were congenital hepatic fibrosis (5), hepatic vein thrombosis (2), portal vein thrombosis (2), and cystic fibrosis (1). Primary indications were repeated variceal bleeding (6), symptomatic hypersplenism (2), and significant liver dysfunction (2). Procedures performed were distal splenorenal bypass (4), side-to-side portocaval shunt (3), proximal splenorenal shunt (2), and an interposition H-graft portocaval shunt (1). There was no perioperative mortality and only minor morbidity. Seventy percent of patients had improvement of their symptoms. Eighty percent of shunts remained patent. Two were occluded at a median follow-up of 50 months (range 0.5–13.16 years). Two patients underwent subsequent liver transplantation. Two patients died at 0.5 and 12.8 years postoperatively, one from multisystem failure with cystic fibrosis and one from post-operative transplant complications. Conclusions. The need for portosystemic shunts in children is rare. However, in the era of liver transplantation, portosystemic shunts in selected patients with well-preserved liver function remains important. We conclude that portosystemic shunts are safe and efficacious in the control of variceal hemorrhage and symptoms related to hypersplenism.
Congenital airway anomalies can be asymptomatic or may cause severe respiratory distress requiring immediate treatment. These anomalies can present early in life, or may be just incidental findings. It is important to recognize these entities to realize their clinical significance and to avoid false diagnosis. In this article, the various congenital airway anomalies and their imaging features by multidetector computed tomography (MDCT) are reviewed in order of occurrence during the embryological timeline. This pictorial essay reviews the various distinct congenital airway lesions and their MDCT manifestations. It also provides insight into the embryological basis of the congenital airway lesions encountered.
Airway; Anomalies; Computed tomography; Congenital
Hepatic encephalopathy most commonly occurs in patients with cirrhosis and end-stage liver disease, however, the disorder can also occur in the presence of intra or extrahepatic shunts when the intrahepatic circulation is effectively bypassed. The majority of extrahepatic shunts described to date develop between a mesenteric vein and inferior vena cava. Herein we report a novel case of a superior mesenteric vein to left internal iliac vein shunt that led to hepatic encephalopathy in a 57 year old woman with no apparent underlying liver disorder. The patient presented with confusion, disorientation and hyperammonemia. Work-up for parenchymal liver disease was negative and liver biopsy findings did not show significant liver disease. Magnetic resonance imaging revealed a serpiginous 1 cm wide shunt that diverted superior mesenteric vein blood from the portal confluence to the left internal iliac vein. Surgical closure of the shunt led to marked improvement of the patient with resolution of hepatic encephalopathy. This report is the first description of a portosystemic shunt, likely congenital, linking these two vessels resulting in clinically significant hepatic encephalopathy. The findings emphasize that abdominal and pelvic imaging should be considered in patients with signs of hepatic encephalopathy that have none to minimal hepatic disease.
Hepatic Encephalopathy; Portosystemic shunt; Non-cirrhotic liver
Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.
Doppler; hepatic; spectral; ultrasound; vascular
High-flow hepatic vascular anomalies with arteriovenous shunting commonly manifest during the neonatal period with signs and symptoms of congestive heart failure, but to our knowledge, they have never been described in patients with hereditary hemorrhagic telangiectasia (HHT). We report here our experience with 3 patients with hepatic arteriovenous malformations (AVMs) who presented with symptoms of high-output congestive heart failure during the neonatal period and were subsequently diagnosed with HHT. Imaging showed large hypervascular lesions and multiple hepatic arteriovenous shunts that differentiated these lesions from liver hemangiomas. Transcatheter embolization was performed in all cases. One infant died of sepsis shortly after embolization; follow-up at the age of 2.5 years of the surviving infants revealed involution of the vascular lesions and no evidence of symptom recurrence. We conclude that severe symptoms related to hepatic AVMs in HHT can occur in the neonatal period and that HHT should therefore be included in the differential diagnosis of symptomatic neonatal hepatic vascular malformations. Imaging plays a key role in differentiating hepatic AVMs from hemangiomas, because the latter require additional pharmacologic treatments. Early transcatheter embolization seems to be effective, but long-term outcomes still need to be assessed.
hereditary hemorrhagic telangiectasia; HHT; genetics; Rendu-Osler-Weber; arteriovenous malformations; visceral; liver; children
We sought to identify and characterize the abnormal vascular structures responsible for pulmonary arteriovenous shunting following the Glenn cavopulmonary shunt. Superior cavopulmonary shunt is commonly performed as part of the staged pathway to total cavopulmonary shunt to treat univentricular forms of congenital heart disease, however, clinically significant pulmonary arteriovenous malformations develop in some patients after the procedure. The causes of pulmonary arteriovenous malformations and other pulmonary vascular changes that occur after cavopulmonary shunt are not known. Using a juvenile lamb model of superior cavopulmonary anastomosis that reliably produces pulmonary arteriovenous malformations, we performed echocardiography and morphological analyses to determine the anatomic site of shunting and to identify the vascular structures involved. Pulmonary arteriovenous shunting was identified by contrast echocardiography in all surviving animals (n = 40) following superior cavopulmonary anastomosis. Pulmonary vascular corrosion casts revealed abnormal tortuous vessels joining pulmonary arteries and veins in cavopulmonary shunt animals but not control animals. In conclusion, unusual channels that bridged pulmonary arteries and veins were identified. These may represent the vascular structures responsible for arteriovenous shunting following the classic Glenn cavopulmonary shunt. Detailed analysis of these structures may elucidate factors responsible for their development.
Heart defects; Congenital pulmonary circulation; Arteriovenous malformation
Congenital absence of portal vein (CAPV) was a rare event in the past. However, the number of detected CAPV cases has increased in recent years because of advances in imaging techniques. Patients with CAPV present with portal hypertension (PH) or porto-systemic encephalopathy (PSE), but these conditions rarely occur until the patients grow up or become old. The patients usually visit doctors for the complications of venous shunts, hepatic or cardiac abnormalities detected by ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). The etiology of this disease is not clear, but most investigators consider that it is associated with abnormal embryologic development of the portal vein. Usually, surgical intervention can relieve the symptoms and prevent occurrence of complications in CAPV patients. Moreover, its management should be stressed on a case-by-case basis, depending on the type or anatomy of the disease, as well as the symptoms and clinical conditions of the patient.
Congenital absence of portal vein; Abernethy malformation; Focal nodular hyperplasia
The purpose of this study was to review the embryology, classification, imaging features and treatment options of Müllerian duct anomalies. The three embryological phases will be described and the appearance of the seven classes of Müllerian duct anomalies will be illustrated using hysterosalpingography, ultrasound and MRI. This exhibit will also review the treatment options, including interventional therapy. The role of imaging is to help detect, classify and guide surgical management. At this time, MRI is the modality of choice because of its high accuracy in detecting and accurately characterising Müllerian duct anomalies. In conclusion, radiologists should be familiar with the imaging features of the seven classes of Müllerian duct anomalies, as the appropriate course of treatment relies upon the correct diagnosis and categorisation of each anomaly.
An inherited basis for congenital extrahepatic portosystemic shunts (EHPSS) has been demonstrated in several small dog breeds. If in general both portocaval and porto-azygous shunts occur in breeds predisposed to portosystemic shunts then this could indicate a common genetic background. This study was performed to determine the distribution of extrahepatic portocaval and porto-azygous shunts in purebred dog populations.
Data of 135 client owned dogs diagnosed with EHPSS at the Faculty of Veterinary Medicine of Utrecht University from 2001 – 2010 were retrospectively analyzed. The correlation between shunt localization, sex, age, dog size and breed were studied. The study group consisted of 54 males and 81 females from 24 breeds. Twenty-five percent of dogs had porto-azygous shunts and 75% had portocaval shunts. Of the dogs with porto-azygous shunts only 27% was male (P = 0.006). No significant sex difference was detected in dogs with a portocaval shunt. Both phenotypes were present in almost all breeds represented with more than six cases. Small dogs are mostly diagnosed with portocaval shunts (79%) whereas both types are detected. The age at diagnosis in dogs with porto-azygous shunts was significantly higher than that of dogs with portocaval shunts (P < 0.001).
The remarkable similarity of phenotypic variation in many dog breeds may indicate common underlying genes responsible for EHPSS across breeds. The subtype of EHPSS could be determined by a minor genetic component or modulating factors during embryonic development.
Congenital disorders of the hepatic portal vasculature are rare in man but occur frequently in certain dog breeds. In dogs, there are two main subtypes: intrahepatic portosystemic shunts, which are considered to stem from defective closure of the embryonic ductus venosus, and extrahepatic shunts, which connect the splanchnic vascular system with the vena cava or vena azygos. Both subtypes result in nearly complete bypass of the liver by the portal blood flow. In both subtypes the development of the smaller branches of the portal vein tree in the liver is impaired and terminal branches delivering portal blood to the liver lobules are often lacking. The clinical signs are due to poor liver growth, development, and function. Patency of the ductus venosus seems to be a digenic trait in Irish wolfhounds, whereas Cairn terriers with extrahepatic portosystemic shunts display a more complex inheritance. The genes involved in these disorders cannot be identified with the sporadic human cases, but in dogs, the genome-wide study of the extrahepatic form is at an advanced stage. The canine disease may lead to the identification of novel genes and pathways cooperating in growth and development of the hepatic portal vein tree. The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis. Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.
Corynebacterium spp. are responsible for an important minority of cases of colonization of cerebrospinal fluid shunts used for the treatment of hydrocephalus. In common with coagulase-negative staphylococci, they present a serious therapeutic problem because they are often resistant to multiple antibiotics. We studied the morphologies of coryneforms in colonized hydrocephalus shunts removed from patients and observed extracellular slime similar in appearance to that seen in coagulase-negative staphylococci. We also studied a series of such isolates from other cases of hydrocephalus shunt colonization using an established laboratory model and consistently observed slime production in these shunts as well. We propose that this might be a further reason for failure to eradicate these organisms without shunt removal as well as a factor in their pathogenesis in device-related infections.
Rendu-Osler-Weber disease is a rare autosomal dominant disorder. Hepatic involvement manifests itself as vascular, parenchymal, and biliary lesions with characteristic telangiectasias and vascular shunts. In a 37-year-old female patient, dynamic contrast-enhanced upper abdominal CT and MRI were performed. CT and MRI revealed dilated celiac trunk and hepatic artery. On early arterial phase, dilated hepatic veins showed significant enhancement. On arterial and portal venous phases, liver showed significantly heterogeneous contrast enhancement and showed homogenous enhancement in the hepatic parenchymal phase. On the magnetic resonance cholangiopancreatography, irregular biliary ducts with strictures and dilatation were seen.
Four patients with Felty's syndrome developed massive upper gastrointestinal bleeding due to oesophageal varices. The underlying hepatic pathology in all 4 was nodular regenerative hyperplasia. This appears to be a difficult histological diagnosis to make, having been initially reported as normal on percutaneous biopsy or as fibrosis or cirrhosis on wedge biopsy. This series brings the total number of cases reported in the English literature of this association to 12, suggesting a definite symptom complex. The portal hypertension seems to be due to a combination of increased splenic blood flow and postsinusoidal resistance. The clinical importance of this syndrome is that the appropriate therapy for bleeding oesophageal varices appears to be shunt procedure such as a splenorenal shunt with splenectomy, which should be well tolerated.
In a prospective study of 170 patients with various types of chronic liver disease, a pulmonary gas transfer defect was found in 20% and mottled shadowing in the chest radiograph in 6%. The presence of these abnormalities was not related to the cause of the liver disease.
Reduction of transfer factor in liver disease was not accompanied by a restrictive ventilatory defect and was found in most cases with mottled radiographs.
The incidence of finger clubbing and the levels of both venoarterial admixture and cardiac output were higher in patients with mottling than in those with normal radiographs. Mottling was also seen in the chest radiographs of five other patients with hepatic cirrhosis who had previously been investigated for cyanosis due to intrapulmonary shunting.
Despite earlier reports of active chronic hepatitis and primary biliary cirrhosis occurring in patients with fibrosing alveolitis, we suggest that these radiographic changes in liver disease are usually caused by a pulmonary vascular disorder, rather than by coincidental lung disease, and are a local manifestation of a generalized vasodilated state. The low incidence of diffuse lung disease complicating chronic liver disease was confirmed by reviewing the hospital necropsy records.
In one patient the radiographic mottling disappeared and the physiological evidence of a circulatory disorder became less marked during a period of improved hepatocellular function.
The treatment of hydrocephalus is a challenging one. The development of shunt devices have greatly improved the survival and quality of life of paediatric patients with hydrocephalus; however, shunt dysfunction is a common problem which represents a significant scope of work for paediatric neurosurgeons with shunt failures occuring in up to 40 to 50% of patients during the first two years after shunt surgery.
Numerous pathologies ranging from congenital to acquired conditions can result in the development of hydrocephalus in the paediatric population. Obstruction of proximal or distal catheter ends, misplacement, infections and over drainage are some of the common problems accounting for shunt failures.
We discussed some of the pertinent problems and nuances involved in treatment of paediatric hydrocephalus with VPS as well as to review the role of endoscopic procedures as an alternative to VPS.
Hydrocephalus; Ventriculo-peritoneal shunt; Ventriculomegaly
Orbital venous pathologies encompass a broad range of entities including tumors, shunts, congenital anomalies, aneurysms, and obstructive lesions. Patients may present with a variety of clinical findings which may include a combination of tumefaction, vascular engorgement, orbital pulsation, and exophthalmos, depending on the relationship between the lesion and the vascular system. Clinical findings may be unreliable in excluding serious underlying disorders, and so an extensive clinical and radiologic evaluation is necessary. This article presents a rare case of spontaneous aseptic cavernous sinus-superior ophthalmic vein thrombosis in a woman on hormone replacement therapy, and illustrates the multidisciplinary approach in diagnosis and management. The literature on issues surrounding this case is reviewed.
The echocardiographic abnormalities of tricuspid valve motion in 2 patients with left ventricular to right atrial shunts are described. In both patients the abnormal anatomy was defined at surgery, in one patient the shunt being above the tricuspid valve leaflets (supravalvar) and in the other patient through the septal leaflet (intravalvar). Different patterns of tricuspid valve systolic fluttering were seen in these two cases and the possible reasons for this are discussed. After surgical closure of the defects the systolic fluttering of the tricuspid valve was no longer observed. Echocardiography appears to be useful in detecting the presence of left ventricular to right atrial shunts which otherwise may be difficult to diagnose.
BACKGROUND: Although about 80% of properly diagnosed patients with hydrocephalus improve after implantation of any model of shunt, the remaining 20% may develop further complications because of inadequate shunt performance. Therefore, hydrocephalus shunts require careful independent laboratory evaluation. METHOD: Computer supported shunt testing, based on the new International Standard Organisation directives, characterises various aspects of pressure-flow performance of shunts such as variability with time, susceptibility to reflux, siphoning, temperature related behaviour, external pressure, the influence of a strong magnetic field (for example, MRI), presence of pulsation in differential pressure, particles in drained fluid, etc. RESULTS: Seven different models of valves, representing most common constructions, have been tested so far. Most contemporary valves have a hydrodynamic resistance which is too low. This may result in overdrainage both related to posture and during nocturnal cerebral vasogenic waves. A long distal catheter increases the resistance of these valves by 100%-200%. Most shunts are very sensitive to the presence of air bubbles and small particles in drained fluid. Few shunt models offer reasonable resistance to negative outlet pressure, preventing complications related to overdrainage. Valves with an antisiphon device may be blocked by raised subcutaneous pressure. All programmable valves are susceptible to overdrainage in an upright position. CONCLUSION: The behaviour of a valve during such testing is of immediate relevance to the surgeon and may not be adequately described in the manufacturer's product information.
Infection is a major cause of CSF shunt failure that places the patient at risk of intellectual impairment, development of loculated CSF compartments, and death. The purpose of this article is to review the published literature related to vancomycin for treatment of pediatric CSF shunt infections. Fifty percent of shunt infections appear within 2 months of shunt placement or revision; 90% occur within 6 months. Ninety percent of organisms infecting CSF shunting devices are Staphylococcus and Streptococcus species. The emergence of methicillin-resistant strains of staphylococci has made vancomycin the antibiotic of choice for these infections. The usual intravenous regimen is 60 mg/kg/day divided every 6 hours. Intraventricular vancomycin should be considered for most patients, starting with 10 mg daily. CSF vancomycin concentrations should be monitored and dosing adjustments made as needed to maintain CSF trough vancomycin concentrations between 5 and 20 mg/L.
cerebrospinal fluid; pediatric; shunt infections; vancomycin; ventriculoperitoneal
The effect of liver disease on glucagon metabolism was examined in nine patients with chronic liver disease who were studied both before and after the creation of a surgical portasystemic shunt. Hepatocellular function did not deteriorate after shunt surgery. However, hepatic perfusion with splanchnic venous blood, as determined by scintisplenoportography, decreased after shunt surgery in six subjects but appeared unaltered in three. Basal plasma immunoreactive glucagon (IRG) levels in the pre-shunt cirrhotic group were significantly greater (p <0·005) than in control subjects and further increased (p <0·05) after shunt surgery. Moreover, the increase in basal IRG after shunt was evident only in patients in whom portasystemic shunting was demonstrably increased by surgery. Despite the higher basal IRG levels postoperatively, shunt surgery in the cirrhotics did not alter basal glucose and insulin levels or the glucose and insulin response to a glucose or protein load. Circulating IRG was heterogeneous in the pre-shunt cirrhotic patients: the 9000 molecular weight fraction comprised 27±4%, the 3500 mol. wt. fraction 71±4%, and the > 40 000 mol. wt. fraction was minimal. After shunt surgery, the relative proportion of the 9000 mol. wt. fraction of IRG (13±3%) decreased significantly (p <0·05) and this fall was associated with a corresponding increase in the 3,500 mol. wt. fraction (84±4%). It is concluded that, in cirrhosis, hyperglucagonaemia is: (1) dependent on the degree of portasystemic shunting rather than impaired hepatocellular function; (2) predominantly due to increased circulating 3500 molecular weight glucagon; and (3) not a major factor in the pathogenesis of carbohydrate intolerance in liver disease.
There is significant overlap in the genes and pathways that control liver development and those that regulate liver regeneration, hepatic progenitor cell expansion, response to injury and cancer. Additionally, defects in liver development may underlie some congenital and perinatal liver diseases. Thus, studying hepatogenesis is important for understanding not only how the liver forms, but also how it functions. Elegant work in mice has uncovered a host of transcription factors and signaling molecules that govern the early steps of hepatic specification, however the inherent difficulty of studying embryogenesis in utero has driven developmental biologists to seek new systems. The rapidly developing vertebrate zebrafish is a favorite model for embryology. The power of forward genetic screens combined with live real-time imaging of development in transparent zebrafish embryos has highlighted conserved processes essential for hepatogenesis and has uncovered some exciting new players. This review will present the advantages of zebrafish for studying liver development, underscoring how studies in zebrafish and mice complement each other. In addition to their value for studying development, zebrafish models of hepatic and biliary diseases are expanding, and using these small, inexpensive embryos for drug screening has become de rigueur. Zebrafish provide a shared platform for developmental biology and translational research, offering innovative methods for studying liver development and disease.
Arterial and arteriovenous abnormalities are reported in association with advanced liver disease, those most commonly recognised are spider naevi, pulmonary arteriovenous shunts, and generalised vasodilatation. The first two cases of peripheral systemic arteriovenous malformations in association with cirrhosis are reported. After liver transplantation in one of these patients the vascular malformation regressed. A review of published works shows that other vascular complications of advanced liver disease such as pulmonary shunts and generalised vasodilation also regress after orthotopic liver transplantation.
Many surgical procedures, including four categories of portal-systemic shunts and a variety of nonshunting operations, have been proposed for patients who bleed from esophagogastric varices. As data have accumulated from clinical trials designed to assess these operations, no single procedure has emerged as ideal for all patients. The urgency of surgical operation, status of hepatic hemodynamics and experience of the surgeon appear to be the most important factors to consider in selecting the appropriate operation for a patient. The timing of the operation with respect to the acute bleeding episode remains controversial. As more effective, conservative methods for temporarily controlling hemorrhage have become available, however, most surgeons now prefer elective procedures because they have lower surgical mortality than emergency intervention. Selective portal-systemic shunts (distal splenorenal shunt and left gastric-vena caval shunt) and nonshunting operations are probably the only procedures that preserve hepatic portal perfusion and thus are less frequently complicated by postoperative encephalopathy than completely diverting shunts. Side-to-side portal-systemic shunts, because they decompress hepatic sinusoids and the splanchnic viscera, are the most effective operations for relieving ascites. None of the available procedures have been proved by controlled trials to be superior to others with respect to long-term postoperative survival.