Sonographic diagnosis of hepatic vascular disorders

Association between Preoperative Retrograde Hepatic Vein Flow and Acute Kidney Injury after Cardiac Surgery

Key questions: Is there a predictive value of hepatic venous flow patterns for postoperative acute kidney injury (AKI) after cardiac surgery? Key findings: In patients who underwent cardiac surgery, retrograde hepatic venous waves (A, V) and their respective ratio to anterograde waves showed a strong association with postoperative AKI, defined as the percentage change of the highest postoperative serum creatinine from the baseline preoperative concentration (%ΔCr). The velocity time integral (VTI) of the retrograde A wave and the ratio of the retrograde and anterograde waves’ VTI were independently associated with AKI after adjustment for disease severity. Take-home message: A higher ratio of retrograde/antegrade waves in hepatic venous retrograde waves, which are related to hepatic stasis, may predict AKI after cardiac surgery. Introduction: Hepatic venous flow patterns reflect pressure changes in the right ventricle and are also markers of systemic venous congestion. Pulsatility of the inferior caval vein was used to predict the risk of acute kidney injury (AKI) after cardiac surgery. Aims: Our objective was to evaluate the association between preoperative hepatic venous flow patterns and the risk of AKI in patients after cardiac surgery. Methods: This prospective, observational study included 98 patients without preexisting liver disease who underwent cardiac surgery between 1 January 2018, and 31 March 2020, at a tertiary heart center. In addition to a routine echocardiographic examination, we recorded the maximal velocity and velocity time integral (VTI) of the standard four waves in the common hepatic vein with Doppler ultrasound. Our primary outcome measure was postoperative AKI, defined as the percentage change of the highest postoperative serum creatinine from the baseline preoperative concentration (%ΔCr). The secondary outcome was AKI, defined by KDIGO (Kidney Disease Improving Global Outcomes) criteria. Results: The median age of the patients was 69.8 years (interquartile range [IQR 25−75] 13 years). Seventeen patients (17.3%) developed postoperative AKI based on the KDIGO. The VTI of the retrograde A waves in the hepatic veins showed a strong correlation (B: 0.714; p = 0.0001) with an increase in creatinine levels after cardiac surgery. The velocity time integral (VTI) of the A wave (B = 0.038, 95% CI = 0.025−0.051, p < 0.001) and the ratio of VTI of the retrograde and anterograde waves (B = 0.233, 95% CI = 0.112−0.356, p < 0.001) were independently associated with an increase in creatinine levels. Conclusions: The severity of hepatic venous regurgitation can be a sign of venous congestion and seems to be related to the development of AKI.

Hemodynamic effect through a novel endoscopic intervention in management of varices and hypersplenism (with video)

BACKGROUND AND AIMS

We previously reported a new and combined EUS-guided intervention in a patient with portal hypertension, consisting of obliteration of varices and partial splenic embolization (PSE). Performing PSE is known to diminish the increase in portal venous pressure after endoscopic intervention for varices. The aim of this study was to use multidetector CT portal venography to evaluate the anatomy of esophagogastric varices (EGV) and the impact on hemodynamics of portosystemic collaterals shortly after the concomitant procedures.

METHODS

From October 2019 to December 2020, 5 patients with cirrhosis and with clinically significant portal hypertension who had variceal bleeding history and hypersplenism were treated with combined endoscopic obliteration for varices and EUS-guided PSE. Multidetector CT portal venography was applied to assess the anatomic drainage patterns of the EGV, diameters of feeders and drainage vessels, and splenic embolization rate.

RESULTS

Within 5 days after concomitant endoscopic interventions, we observed decreased mean diameters of the left gastric vein, short gastric vein, and azygos vein as .3 mm, 1.0 mm, and 5.2 mm compared with 3.11 mm, 7.1 mm, and 5.4 mm before the procedures, respectively. Patients showed increased white blood cells (mean count of 2.7 × 10⁹/L before vs 5.8 × 10⁹/L after) and platelets (mean count of 52.8 × 10⁹/L before vs 95.8 × 10⁹/L after). The mean splenic embolization rate was 64.5% (range, 28.8%-84.6%).

CONCLUSIONS

Our experience may illustrate an alternative technique of combining EUS-guided PSE with endoscopic therapy of varices to treat patients with portal hypertension.

[Budd-Chiari syndrome, review and illustration]

Budd-Chiari syndrome is a rare vascular disorder characterized by obstruction of the hepatic venous outflow. Various diseases causing coagulopathy play a role in aetiology, such as myeloproliferative disorders. Acute vascular occlusion may lead to acute phlebitis with fever. The classic triad of acute liver failure may be present with ascites, hepatomegaly, and abdominal pain. However, subacute courses of disease were also observed. Because of the variable symptoms and severity extent, depending on the acuity of the course and the extent of the affected vessels, diagnosis is often difficult. Sonography, as a ubiquitously available and cost-effective diagnostic tool, plays a leading role. Doppler ultrasonography can be used to visualize hemodynamics in particular. In acute thrombotic occlusion, the affected hepatic veins usually cannot or only partially be visualized. In non-occluding thrombi, turbulent flow patterns may develop in the area of venous outflow obstruction, and flow velocity is then increased in the area of stenosis. Contrast enhanced ultrasound offers even better specificity of diagnosis. Computed tomography and magnetic resonance imaging can directly visualize thrombi and the cause of obstruction. Once the diagnosis is confirmed, anticoagulation must be initiated, but therapy of the underlying disease must also be started. If symptom-controlling measures are not sufficient, angioplasty/stenting to reopen short-segment stenoses or implantation of a TIPSS device may be considered. Liver transplantation remains ultima ratio. As studies on the precision of diagnostic methods are controversial, the characteristics of imaging for BCS are therefore summarized in this review on the basis of several illustrating case reports.

Feline abdominal ultrasonography: what's normal? what's abnormal? Hepatic vascular anomalies

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Although hepatic vascular anomalies are less common than disorders of the hepatic parenchyma and biliary tree, our understanding and recognition of these is gradually increasing with advancements in ultrasound technology and image quality.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even differentiating between normal variation and pathological changes can be challenging for all but the most experienced. In addition, some views may be obscured by overlying structures; for example, the termination of a shunt entering the left phrenic or azygous veins is often difficut to see due to the high probability of lung passing between the shunt and the transducer as the cat breathes.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the appearance of various hepatic vascular anomalies. It is aimed at general practitioners who wish to improve their knowledge and confidence in feline abdominal ultrasound and is accompanied by high-resolution images. Ultrasound of the liver and biliary tree were discussed in articles published in January and May 2019, respectively.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Large-volume paracentesis effects plasma disappearance rate of indo-cyanine green in critically ill patients with decompensated liver cirrhosis and intraabdominal hypertension

BACKGROUND

Ascites is a major complication of decompensated liver cirrhosis. Intraabdominal hypertension and structural alterations of parenchyma involve decisive changes in hepatosplanchnic blood flow. Clearance of indo-cyanine green (ICG) is mainly dependent on hepatic perfusion and hepatocellular function. As a consequence, plasma disappearance rate of ICG (ICG-PDR) is rated as a useful dynamic parameter of liver function. This study primarily evaluates the impact of large-volume paracentesis (LVP) on ICG-PDR in critically ill patients with decompensated cirrhosis. Additionally, it describes influences on intraabdominal pressure (IAP), abdominal perfusion pressure (APP), hepatic blood flow, hemodynamic and respiratory function.

METHODS

We analyzed LVP in 22 patients with decompensated liver cirrhosis. ICG-PDR was assessed by using noninvasive LiMON technology (Pulsion® Medical Systems; Maquet Getinge Group), and hepatic blood flow was analyzed by color-coded duplex sonography.

RESULTS

Paracentesis of a median volume of 3450 mL ascites evoked significant increases of ICG-PDR from 3.6 (2.8-4.6) to 5.1 (3.9-6.2)%/min (p < 0.001). Concomitantly, we observed a raise in "ICG-Clearance" from 99 (73.5-124.5) to 104 (91-143.5) mL/min/m2 (p = 0.005), while circulating blood volume index was unchanged [2412 (1983-3025) before paracentesis vs. 2409 (1997-2805) mL/m2, p = 0.734]. Sonography revealed a significant impact of paracentesis on hepatic blood flow: Hepatic artery resistance index dropped from 0.74 (0.68-0.75) to 0.68 (0.65-0.71) (p < 0.001) and maximum flow velocity in hepatic vein increased from 24 (17-30) to 30 (22-36) cm/s (p < 0.001). Consistent with previous studies, paracentesis caused significant decreases in IAP from 19.0 (15.0-20.3) to 11.0 (8.8-12.3) mmHg (p < 0.001) and central venous pressure from 22.5 (17.8-29.0) to 17.5 (12.8-24.0) mmHg (p < 0.001) with inverse increases in APP from 63.0 (56.8-69.5) to 71.0 (65.5-78.5) mmHg (p < 0.001). Changes in ICG-PDR were concomitant with changes in IAP (r = - 0.602) and APP (r = 0.576). Moreover, we found a substantial improvement in respiratory function. By contrast, hemodynamic parameters assessed by transpulmonary thermodilution, serum bilirubin and international normalized ratio did not change after paracentesis.

CONCLUSION

Critically ill patients with decompensated cirrhosis and elevated IAP showed dramatically impaired ICG-PDR. Paracentesis evoked an improvement in ICG-PDR in parallel with a decreased IAP and an increased APP, while conventional parameters of liver function did not change. This effect on ICG-PDR is mainly referable to a relief of intraabdominal hypertension and changes in hepatosplanchnic blood flow.

Sonographic Evaluation of the Portal and Hepatic Systems

Color and spectral Doppler are used to evaluate flow characteristics in the portal and hepatic vessels. On occasion, suprahepatic pathologies are reflected in the flow characteristics of the hepatic veins and transmitted to the portal venous system across the hepatic sinusoids. Few definitive duplex findings are pathognomic for portal hypertension. Evaluation of the portal venous system is analogous to a puzzle. A picture of the processes can only be attained after many of the pieces are assembled.

Thrombotic Venous Diseases of the Liver

Thrombotic venous diseases of the liver do not occur frequently, but when they do, they can present as difficult diagnostic and therapeutic challenges. The aim of this article is to review the epidemiology, pathogenesis, diagnosis, and therapeutic options of these serious vascular problems.

Doppler ultrasonography measurement of hepatic hemodynamics during Valsalva maneuver: healthy volunteer study

Purpose:

The aim of our study was to assess the hemodynamic change of liver during the Valsalva maneuver using Doppler ultrasonography.

Methods:

Thirty healthy men volunteers were enrolled (mean age, 25.5±3.64 years). The diameter, minimal and maximal velocities, and volume flow of intrahepatic inferior vena cava (IVC), middle hepatic vein (MHV), and right main portal vein (RMPV) was measured during both rest and Valsalva maneuver. These changes were compared using paired t-test.

Results:

The mean diameters (cm) of the intrahepatic IVC at rest and Valsalva maneuver were 1.94±0.40 versus 0.56±0.66 (P<0.001). The mean diameter (cm), minimal velocity (cm/sec), maximal velocity (cm/sec), and volume flow (mL/min) of MHV at rest and Valsalva maneuver were 0.60±0.15 versus 0.38±0.20 (P<0.001), -7.98±5.47 versus 25.74±13.13 (P<0.001), 21.34±6.89 versus 35.12±19.95 (P=0.002), and 106.94±97.65 versus 153.90±151.80 (P=0.014), respectively. Those of RMPV at rest and Valsalva maneuver were 0.78±0.21 versus 0.76±0.20 (P=0.485), 20.21±8.22 versus 18.73±7.43 (P=0.351), 26.79±8.85 versus 24.93±9.91 (P=0.275), and 391.52±265.63 versus 378.43±239.36 (P=0.315), respectively.

Conclusion:

The blood flow velocity and volume flow of MHV increased significantly during Valsalva maneuver. These findings suggest that hepatic vein might play an important role to maintain venous return to the heart during the maneuver.

Nuclear medicine dynamic investigations in the diagnosis of Budd-Chiari syndrome

AIM

To investigate the hepatic hemodynamics in the Budd-Chiari syndrome (BCS) using per-rectal portal scintigraphy (PRPS) and liver angioscintigraphy (LAS).

METHODS

Fourteen consecutive patients with BCS were evaluated by PRPS between 2003 and 2012. Ten of them underwent LAS and liver scan (LS) with Tc-99m colloid. Eleven patients had clinical manifestations and three were asymptomatic, incidentally diagnosed at PRPS. The control group included 15 healthy subjects. We used new parameters at PRPS, the liver transit time of portal inflow and the blood circulation time between the right heart and liver. PRPS offered information on the hepatic areas missing venous outflow or portal inflow, length and extent of the lesions, open portosystemic shunts (PSS), involvement of the caudate lobe (CL) as an intrahepatic shunt and flow reversal in the splenic vein. LAS was useful in the differential diagnosis between the BCS and portal obstructions, highlighting the hepatic artery buffer response and reversed portal flow. LS offered complementary data, especially on the CL.

RESULTS

We described three hemodynamic categories of the BCS with several subtypes and stages, based on the finding that perfusion changes depend on the initial number and succession in time of the hepatic veins (HVs) obstructions. Obstruction of one hepatic vein (HV) did not cause opening of PSS. The BCS debuted by common obstruction of two HVs had different hemodynamic aspects in acute and chronic stages after subsequent obstruction of the third HV. In chronic stages, obstruction of two HVs resulted in opening of PSS. The BCS, determined by thrombosis of the terminal part of the inferior vena cava, presented in the acute stage with open PSS with low speed flow. At least several weeks are required in the obstructions of two or three HVs for the spontaneous opening of dynamically efficient PSS. The CL seems to have only a transient important role of intrahepatic shunt in several types of the BCS.

CONCLUSION

Dynamic nuclear medicine investigations assess the extent and length of hepatic venous obstructions, open collaterals, areas without portal inflow, hemodynamic function of the CL and reverse venous flow.

Management of portal hypertension in children with portal vein thrombosis

Portal vein thrombosis (PVT) is a common cause of portal hypertension in children. Predisposing conditions for PVT are obscure in more than half of the cases. Variceal bleeding and splenomegaly are the most frequent initial manifestations. Radiologic imaging studies are the mainstay for diagnosis. Treatment includes pharmacologic, endoscopic, and surgical modalities. β-Adrenergic blockers are not routinely used in children because of unproven efficacy and significant adverse effects. Endoscopic methods, such as sclerotherapy and endoscopic variceal ligation (EVL), are highly effective in the treatment of acute variceal bleeding and eradication of varices. EVL is the treatment of choice because of minimal complications and the need for few endoscopic sessions. EVL facilitates portal decompression either by the formation of collateral vessels or by surgical portosystemic shunting, when vessels grow to the proper diameter for anastomosis. Surgical portosystemic shunts are reserved for refractory cases because of significant complications and technical difficulties. Transjugular portosystemic shunts have an emerging role in the management of portal hypertension caused by PVT. PVT may occur in the posttransplant setting, but optimal management is not defined yet.

Understanding the spectral Doppler waveform of the hepatic veins in health and disease

Duplex Doppler sonography is a fundamental component of the complete ultrasonographic examination of the liver. Accurate interpretation of the spectral Doppler tracing from the hepatic veins is valuable, as it reflects important cardiac and hepatic physiology. Normally, there are four phases: A, S, V, and D; the S and D waves indicate flow in the antegrade direction toward the heart. In hepatic and cardiac disease, these normal waves may be absent, a finding indicative of flow in a nonphysiologic manner. In addition, transient patient factors such as phase of the respiratory cycle may influence the appearance of the spectral tracing. Familiarity with the normal and abnormal spectral Doppler waveforms from the hepatic veins and knowledge of their respective physiology and pathophysiology provide valuable insights. Systematic analysis of the direction, regularity, and phasicity of the spectral tracing and the ratio of the amplitudes of the S and D waves allows one to arrive at the correct differential diagnosis in most situations.

Diagnostic and interventional radiology for Budd-Chiari syndrome

Budd-Chiari syndrome is a heterogeneous group of disorders characterized by hepatic venous outflow obstruction that involves one or more draining hepatic veins. Its occurrence in populations in the western hemisphere is commonly associated with hypercoagulative states. Clinical manifestations in many cases are nonspecific, and imaging may be critical for early diagnosis of venous obstruction and accurate assessment of the extent of disease. If Budd-Chiari syndrome is not treated promptly and appropriately, the outcome may be dismal. Comprehensive imaging evaluations, in combination with pathologic analyses and clinical testing, are essential for determining the severity of disease, stratifying risk, selecting the appropriate therapy, and objectively assessing the response. The main goal of treatment is to alleviate hepatic congestion, thereby improving hepatocyte function and allowing resolution of portal hypertension. Various medical, endovascular, and surgical treatment options are available. Percutaneous and endovascular procedures, when performed in properly selected patients, may be more effective than medical treatment methods for preserving liver function and arresting disease progression in the long term. In addition, such procedures are associated with lower morbidity and mortality than are open surgical techniques.

Early sonographic assessment of Budd-Chiari syndrome after orthotopic liver transplantation

Budd-Chiari syndrome is a rare vascular complication of liver transplantation that may result in loss of the graft and a high mortality risk. Therefore, early diagnosis is extremely important to allow preservation of the graft and improve the prognosis. We describe the sonographic findings in a patient in whom Budd-Chiari syndrome occurred 2 days after orthotopic liver transplantation.

Ultrasonographic diagnosis of unusual portal vascular abnormalities in two cats

Two cases of ascites secondary to portal vascular abnormalities associated with portal hypertension are described. In the first case a five-month-old cat was presented with recurrent ascites and investigations showed that the underlying cause was a hepatic arteriovenous fistula. Ultrasonography showed direct communication of the coeliac artery and right branch of the portal vein. There was also hepatofugal flow in the main portal vein consistent with portal hypertension. The ultrasonographic features were similar to those seen in dogs with hepatic arteriovenous fistulae. In the second case, ascites, portal hypertension and an intraluminal mass in the main portal vein was diagnosed in a 16-year-old cat that had been presented with hyperthyroidism and hepatomegaly. Acquired portosystemic collaterals involving the left renal vein were present. Additional diagnostic investigations were not permitted. Ultrasonography was useful in both cases to document portal hypertension and the underlying cause.

Ultrasound of the liver

This article summarizes the recent advances in ultrasound imaging of the liver, especially contrast-enhanced imaging. Contrast-enhanced ultrasound has dramatically changed the role of ultrasound in liver tumor characterization, detection, and other applications. Available ultrasound contrast agents, agents under development, contrast-specific imaging techniques, and its applications in liver imaging are discussed.

Correction of Left Hepatic Vein Redundancy in Paediatric Liver Transplantation

Redundancy of hepatic vein in the venous outflow reconstruction of partial graft in paediatric liver transplantation may occur when the graft hepatic vein is longer than anticipated. We describe two cases with outflow obstruction due to hepatic vein redundancy. The correction of the redundancy was made by pulling the graft caudally and to the left or right side of the abdominal cavity as determined by Doppler ultrasonography.

Effects of splenohepatopexy and omentopexy in experimentally induced infrahepatic portal hypertension in rats

The purpose of this study was to determine whether splenohepatopexy (SHP) or omental transposition (OP) could reverse the portal hypertension (PH) induced by portal vein ligation (PVL). Fifty-eight Wistar rats divided into four groups: in group A (22 rats) PH was produced by calibrated PVL. In group B (8 rats), SHP was performed. Group C animals (13 rats) underwent SHP and PVL. In group D (15 rats) both PVL and OP were done. In all of the rats, the portal pressures (PP) were measured before and after the production of PVL. For SHP, small areas on the spleen and liver capsula were stripped off, and these two areas were placed together. In group D, an omentum patch was tied on the prepared liver surface. Twelve weeks after surgery, the PP were measured again and portal angiography was done. The liver, omentum and spleen were histopathologically examined. In all of the groups, the PP after PVL were significantly higher than before PVL. Twelve weeks after surgery, the PP of SHP and OP groups were significantly lower than those with PVL alone. Angiographic study showed many collaterals between transposed tissue and liver. Histopathologically, the collaterals of animals with SHP or OP were found to be well developed to allow sufficient flow for PP reduction. Both SHP and OP may reverse the increased PP in PVL model of PH. In the future; these methods may be alternative techniques for PP reduction in human beings as well.

Emergency Doppler evaluation of the liver and kidneys

Doppler ultrasound is useful in the emergent evaluation of the liver and kidney transplant patient. Arterial stenosis, pseudoaneurysm, and venous thrombosis are treatable causes of allograft failure that can be detected easily with color and spectral Doppler. Doppler has a limited but important role in the emergent evaluation of the native liver and kidneys, usually involving prior biopsy or instrumentation.

Hepatobiliary imaging and its pitfalls

In summary, US is the initial imaging modality for the evaluation of acute right upper quadrant pain. It permits accurate diagnosis of acute cholecystitis and successfully identifies multiple other causes of patient symptomatology. Some of these processes lie outside the hepatobiliary system and include renal infection and obstruction, pancreatitis and its sequelae, duodenal or colonic perforation or mass lesions, peritoneal tumor spread, adrenal hemorrhage, and even remote problems, such as pneumonia. The limitations on US include incomplete imaging of the liver, most often at the dome or beneath ribs on the surface, and incomplete visualization of lesion boundaries, particularly with some infections and tumors. For these clinical scenarios, contrast-enhanced CT is complementary to US and should be encouraged. In the biliary tree, US has limitations in situations in which the ducts are not dilated and sometimes with imaging the extra hepaticducts, especially distally. For these patients, CT or MR imaging (MRCP) is especially useful. If one keeps the clinical scenario in mind and always images a patient where he or she hurts, US is a powerful and effective diagnostic method for evaluating acute right upper quadrant pain.

Hepatic venoplasty in right lobe live donor liver transplantation

Inclusion of the middle hepatic vein (MHV) in a right lobe graft is essential to guarantee uniform venous drainage and optimum function of the graft, but end-to-end recipient-to-donor MHV anastomosis may result in outflow obstruction. To avoid outflow obstruction, we designed the venoplasty technique. From September 2000 to November 2002, 65 adult patients received right lobe live donor liver transplantation (LDLT) with grafts containing the right hepatic vein (RHV) and MHV. In the first 34 recipients, the graft RHV and MHV were anastomosed to the recipients' RHV and MHV/left hepatic vein, respectively. For the subsequent 31 recipients, the MHV was joined to the RHV at the back table to form a triangular common orifice. The septum in between the two hepatic veins was divided at the middle and sutured transversely to remove the ridge in between and to create a large opening. The common orifice was anastomosed to a matched-size triangular opening in the recipient's inferior vena cava. After reperfusion, the presence of triphasic pulsatility on spectral Doppler tracing was regarded as a sign of perfect reconstruction. In the first group, Doppler study showed little flow in the MHV in 3 patients, absent pulsatility in the MHV after portal vein reperfusion in 4 patients, and absent pulsatility in the MHV after hepatic artery reperfusion in 5 patients. In the second group, excellent triphasic pulsatility was seen in all except 1 patient (12 of 34 versus 1 of 31, P =.001). A significant increase in the peak flow velocity was seen in the MHV in the second group (median, 19.45 cm/sec versus 31.4 cm/sec, P<.001). Less time was required to complete the hepatic vein anastomoses in the second group (40 minutes versus 27 minutes, P<.001). In conclusion, hepatic venoplasty technique facilitates the implantation of the right lobe graft and guarantees outflow in the MHV.

Portal Hypertension

Portal hypertension is a serious condition that is most commonly a result of cirrhosis. It is defined as an increase in portal venous pressure that impedes blood flow into the liver. This review describes portal hypertension and its typical etiologies. Twodimensional and Doppler sonography play important roles in the diagnosis and surveillance of patients with portal hypertension.

Doppler sonography measurement of portal blood flow velocity after glucagon injection in patients with chronic HCV infection

Doppler sonography measurement of portal flow velocity (PFV) after glucagon injection was performed in 45 patients with chronic hepatitis C virus (HCV) infection. Patients were divided into three groups: group 1 = no or mild liver fibrosis; group 2 = moderate to severe liver fibrosis, and group 3 = liver cirrhosis. All patients were examined using a Doppler ultrasound (US) multipurpose equipment and a convex 3.5-MHz probe, 10 min before (baseline), as well as 5 and 10 min after, IV administration of 1 mg of glucagon chloride. No significant differences were found in mean baseline PFV among group 1 (19.4 +/- 2.4 cm/s), group 2 (20.1 +/- 3.6 cm/s) and group 3 (17.5 +/- 3.7 cm/s). Five minutes after glucagon injection, all three groups showed significantly increased values of mean PFV (25.6 +/- 4.8, 23.7 +/- 4.0 and 19.5 +/- 5.0 cm/s, respectively; p < 0.05 vs. baseline). The mean increase of PFV above baseline was significantly higher in group 1 (7.9 +/- 3.7 cm/s) than in group 2 (4.5 +/- 3.9 cm/s) (p < 0.05) or in group 3 (2.7 +/- 2.3 cm/s) (p < 0.05). A significant inverse correlation was found between individual values of fibrosis score and of individual increase of PFV. In patients with chronic HCV infection, Doppler sonography measurement of PFV after glucagon injection could be useful in assessing the severity of liver histological damage.

Budd-Chiari syndrome: spectrum of appearances of acute, subacute, and chronic disease with magnetic resonance imaging

The purpose of this study was to describe our collective experience in the magnetic resonance (MR) investigation of patients with proven acute, subacute, and chronic Budd-Chiari syndrome and to demonstrate the spectrum of appearances on T1- and T2-weighted as well as dynamic post-gadolinium spoiled gradient-echo imaging. All patients with proven Budd-Chiari syndrome who underwent MR examinations between June, 1992 and October, 1998 were included in the study. Fourteen patients were included in the study: four with acute, three with subacute, three with chronic, and four with acute superimposed on either subacute (two) or chronic (two) Budd-Chiari syndrome. MR imaging features were retrospectively evaluated to determine: a) liver morphology, b) pattern of signal intensity (SI) on T1-weighted images, c) pattern of SI on T2 weighted images, d) dynamic enhancement characteristics, e) presence or absence of visible venous thrombosis, and f) presence or absence of venous macroscopic collaterals. The MR findings were correlated with surgical, histopathological, and laboratory data to determine imaging characteristics related to the chronicity of the disease process. Hepatic venous thrombosis or absence of hepatic venous flow was demonstrated in all patients in the study. In the four patients with acute Budd-Chiari syndrome, the liver periphery was moderately low signal on T1 and moderately high signal on T2-weighted images relative to the central liver; both early and late gadolinium-enhanced images revealed diminished peripheral enhancement. In the three patients with subacute Budd-Chiari syndrome, the liver periphery was moderately low signal on T1, and moderately high signal on T2-weighted images, while early and late gadolinium-enhanced images revealed heterogenously increased enhancement within the liver periphery. In the three patients with chronic Budd-Chiari syndrome, the SI differences between peripheral and central liver were minimal on T1- and T2-weighted images, and enhancement differences were also minimal. Extensive bridging intrahepatic and capsular venous collaterals were visualized in chronic cases. In the four patients with acute Budd-Chiari syndrome superimposed on more chronic disease, a combination of gadolinium enhancement patterns was observed on MR images. Enhancement patterns between central and peripheral liver were different for acute, subacute, and chronic Budd-Chiari syndromes, suggesting differentiation between these phases of the disease process. Application of this pattern approach permitted recognition of acute changes superimposed on more chronic disease.

Evaluation of extrahepatic portal hypertension and surgical portal systemic shunts by intravenous CT portography

The purpose of this study was to evaluate the splenoportal (SP) axis and patency of portal systemic shunts in extrahepatic portal venous obstruction (EHO) by intravenous CT portography (CTP). Fifty-five patients of preshunt EHO, and 21 patients of postshunt (surgical portal systemic shunts) EHO, were subjected to intravenous CTP on a subsecond helical CT scanner. Thin, axial sections and three dimensional (3-D) reconstructions, including maximum intensity projection (MIP) and shaded surface display (SSD), were obtained. The findings were correlated with Color Doppler Flow Imaging (CDFI). In the EHO preshunt group, the site of the block demonstrated on CTP correlated with CDFI in 53 of 55 cases. In the postshunt group, shunt patency evaluation by CTP was in agreement with CDFI in 19 of 21 patients (8 patent; 13 blocked). Two patients in each group could not be evaluated on CDFI, while CTP could provide the appropriate information. There was no false positivity or negativity with CTP in patients evaluated on both modalities. The etiology of EHO, the global view of collaterals, and the 3-D anatomy of SP axis could be well depicted and was well accepted by the surgeons. We conclude that CTP is an impressive new technique that can effectively evaluate pre- and postshunt cases of EHO.

Ultrasound and MR findings in acute Budd-Chiari syndrome with histopathologic correlation

This report describes the sonographic and MR appearances of acute Budd-Chiari syndrome (BCS) in a 30-year-old woman. Current imaging techniques including duplex Doppler sonography and dynamic gadolinium-enhanced MRI were employed, and direct histopathologic correlation was made. Duplex Doppler sonography revealed a heterogeneous enlarged liver, no flow in the left and middle hepatic veins, and only trace abnormal flow in the distal-most right hepatic vein. Dynamic serial gadolinium-enhanced, spoiled gradient echo imaging demonstrated early homogeneous enhancement of an enlarged caudate lobe, as well as heterogeneously decreased enhancement of the remainder of the hepatic parenchyma. This differential enhancement pattern persisted on delayed imaging. Patent hepatic veins were not demonstrated on any sequence. Associated findings included hepatomegaly, ascites, and patent portal vasculature. These imaging findings were interpreted as consistent with acute BCS. Within 10 days, the patient underwent orthotopic liver transplantation. Histopathology demonstrated hepatic necrosis and hepatic venous thrombosis consistent with acute BCS.