Assessment of portal venous system patency in the liver transplant candidate: a prospective study comparing ultrasound, microbubble-enhanced colour Doppler ultrasound, with arteriography and surgery

The Role of Contrast-Enhanced Ultrasound (CEUS) in the Detection of Neoplastic Portal Vein Thrombosis in Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the principal primary liver cancer and one of the most frequent malignant tumors worldwide in patients with chronic liver disease. When diagnosed at an advanced stage, it is often associated with portal vein tumor thrombosis (PVTT), which heavily affects patients' prognosis. Imaging evaluation is crucial in PVTT detection and staging; computed tomography and magnetic resonance are the principal diagnostic tools. Contrast-enhanced ultrasound (CEUS) is a non-invasive and easily repeatable method that can also be used in patients with impaired renal function. It represents an important means for the identification of PVTT, particularly differentiating neoplastic and non-neoplastic thrombosis through the analysis of ultrasound enhancement characteristics of the thrombosis (arterial hyperenhancement and portal washout), thus allowing more refined disease staging, appropriate treatment planning, and response evaluation, along with prognosis assessment.

Porto-spleno-mesenteric venous thrombosis after elective splenectomy: a retrospective cohort study

Background

Elective splenectomy is the main treatment for a wide range of haematological diseases. Porto-spleno-mesenteric venous thrombosis represents one of the most severe complications of this procedure. The aim of this study was to evaluate risk factors associated with development of porto-spleno-mesenteric venous thrombosis after elective splenectomy.

Methods

All cases of elective splenectomy carried out from April 1st 2017 to January 31st 2023 were included in this single centre retrospective cohort study. Patients' demographics and perioperative data were analysed and correlated with the incidence of postoperative thrombosis. All patients underwent postoperative doppler ultrasound screening for thrombosis. Analysis was performed using SPSS 28, with p-value < 0.05 considered significant.

Results

Twenty-two patients (10 women, 12 men) underwent splenectomy during the study period. Indications were: immune thrombocytopenia (n: 6), myeloproliferative disorder (n: 6), hereditary spherocytosis (n: 4), thalassemia (n: 1), lymphoma (n: 1), leukaemia (n: 1), other malignancies (n: 3). Six patients developed porto-spleno-mesenteric venous thrombosis and only 2 of them were symptomatic. Patients were treated with anticoagulation therapy with complete resolution. Analysis identified three main factors associated with thrombosis: spleen diameter (p = 0.03), myeloproliferative disorder (p = 0.02), intraoperative platelet transfusion (p = 0.002) and intraoperative red blood cells transfusion (p = 0.009).

Conclusion

Standardized postoperative screening allows prompt diagnosis and treatment of porto-spleno-mesenteric venous thrombosis even in asymptomatic cases. Patient with splenomegaly and affected by myeloproliferative disorder have a greater risk to develop this complication.

Portal Vein Thrombosis in Cirrhosis

Patients with cirrhosis of the liver are at high risk of developing portal vein thrombosis (PVT), which has a complex, multifactorial cause. The condition may present with a myriad of symptoms and can occasionally cause severe complications. Contrast-enhanced computed tomography (CT) is the gold standard for the diagnosis of PVT. There are uncertainties regarding the effect on PVT and its treatment outcome in patients with cirrhosis. The main challenge for managing PVT in cirrhosis is analyzing the risk of hemorrhage compared to the risk of thrombus extension leading to complications. All current knowledge regarding non-tumor PVT in cirrhosis, including epidemiology, risk factors, classification, clinical presentation, diagnosis, impact on natural history, and treatment, is discussed in the present article.

Portal vein thrombosis in patients with chronic liver diseases: From conventional to quantitative imaging

Portal vein thrombosis is a pathological condition characterized by the lumen occlusion of the portal vein and its intrahepatic branches, commonly associated to chronic liver diseases. Portal vein thrombosis is often asymptomatic and discovered as an incidental finding in the follow-up of chronic hepatopathy. Imaging plays a pivotal role in the detection and characterization of portal vein thrombosis in patients with hepatocellular carcinoma. Ultrasound and Color-Doppler ultrasound are usually the first-line imaging modalities for its detection, but they have limits related to operator-experience, patient size, meteorism and the restrained field-of view. Unenhanced cross-sectional imaging doesn't provide specific signs of portal vein thrombosis except under certain specific circumstances. Conventional contrast-enhanced imaging can depict portal vein thrombosis as an endoluminal filling defect best detected in venous phase and can differentiate between non-neoplastic and neoplastic thrombus based on the contrast enhanced uptake, but not always rule-out the malignant nature. Functional and quantitative imaging techniques and software seem to be more accurate. The purpose of this work is to provide the reader with an accurate overview focused on the main imaging features of portal vein thrombosis.

Progress in clinical diagnosis and treatment of cavernous transformation of the portal vein

Cavernous transformation of the portal vein (CTPV) refers to the compensatory neoformation of venous collaterals around the hepatic portal after the main portal vein or its branches are blocked, in order to maintain liver blood perfusion. This disease is relatively rare, and in clinical practice, its etiology, diagnosis, and treatment are not well understood. Patients with portal hypertension-related syndromes need to receive active treatment. The main goal of treatment is to prevent upper gastrointestinal hemorrhage and hypersplenism caused by portal hypertension, and to restore hepatopetal portal blood perfusion. It is necessary to fully assess the patient's condition and understand the best indications for each treatment. On this basis, we should adopt individualized comprehensive treatment strategies. This article reviews the latest advances in the understanding of the etiology, diagnosis, classification, and treatment of CTPV.

Future developments in the imaging of the gastrointestinal tract: the role of ultrasound

PURPOSE OF REVIEW

The purpose of this review is to summarize the utilization and most recent developments with regard to the use of ultrasound when imaging the abdomen and gastrointestinal tract.

RECENT FINDINGS

Although the use of ultrasound to assess the anatomy of the various abdominal organs is well established within radiology and critical care, its use as part of functional and physiological assessment is still evolving. Recent developments have extended the use of ultrasound beyond standard B-mode/2D imaging techniques to incorporate more functional and haemodynamic assessment. These include the use of contrast-enhanced ultrasound (CEUS), elastography, and colour Doppler techniques.

SUMMARY

Whilst Doppler techniques are reasonably well established within critical care ultrasound (CCUS), especially in echocardiography, CEUS and elastography are less well known. CEUS utilizes a purely intravascular contrast agent whilst elastography measures the degree of deformation or stiffness in various organs. Whilst their use individually may be limited; they may play a role in a multiparametric assessment. Mirroring the overall trends in critical care ultrasound development, abdominal ultrasound assessment is best integrated in a holistic approach and adapted to the individual patient.

Contrast imaging ultrasound for the detection and characterization of carotid vulnerable plaque

Not only the degree of luminal narrowing but also the plaque morphology and composition play an important role in risk stratification of carotid atherosclerotic lesions. During the last few years, carotid contrast-enhanced ultrasound (CEUS) has emerged as a valuable imaging tool to assess such vulnerable carotid plaques. This review article discussed the use of CEUS for the detection of carotid plaque irregularities and ulcerations as well as the quantification of intraplaque neovascularization and its correlation with histology and inflammatory biomarkers. Apart from evaluating for markers of vulnerable carotid plaques, CEUS enhancement is directly associated with past cerebrovascular events. More importantly, preliminary evidence has shown that CEUS could be used to predict future cerebrovascular and cardiovascular events. Despite the progress in CEUS imaging for carotid atherosclerotic disease, past studies still suffer from the retrospective nature, small sample size, and a lack of matched, well controlled prospective studies. In the future, large multi-center prospective studies addressing the relationship between CEUS findings and patient clinical outcomes in carotid atherosclerotic disease are warranted.

General principles and overview of vascular contrast-enhanced ultrasonography

Ultrasonography (US) is the first-line modality for the evaluation of vascular pathology. Although well-established for many diseases, US has inherent limitations that can occasionally hinder an accurate diagnosis. The value of US was improved by the introduction of microbubbles as ultrasonographic contrast agents (UCAs) and the emergence of contrast-enhanced ultrasonography (CEUS), following the introduction of second-generation UCAs and the emergence of modern contrast-specific techniques. CEUS offers valuable information about vascular disease, both on a macrovascular and a microvascular level, with well-established applications for carotid disease, post-interventional follow-up of abdominal aortic aneurysms, and the assessment of portal vein thrombosis. The purpose of this review is to discuss the principles of CEUS and to present an overview of its vascular applications.

Diagnosis, Development, and Treatment of Portal Vein Thrombosis in Patients With and Without Cirrhosis

Portal vein thrombosis unrelated to solid malignancy is common in patients with cirrhosis, but less frequently observed in patients without cirrhosis. Prompt diagnosis and management of acute symptomatic portal vein thrombosis are essential. Failure to detect and treat thromboses can result in mesenteric ischemia, chronic cavernous transformation, and complications of portal hypertension. In patients with cirrhosis, development of portal vein thrombosis is often insidious and remains undetected until its incidental detection. Management of portal vein thrombosis in patients with cirrhosis is more controversial. However, there are data to support treatment of specific patients with anticoagulation agents. We review the common and distinct features of portal vein thromboses in patients without liver tumors, with and without cirrhosis.

Application of contrast-enhanced ultrasound after liver transplantation: Current status and perspectives

Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents (UCAs), in combination with contrast-specific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and post-transplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrast-enhanced ultrasound applications in liver transplantation.

Radiological Diagnosis of Portal/Mesenteric Vein Occlusion

Background

In contrast to an acute occlusion of the visceral arteries, which is the most important differential diagnosis for an occlusion of the portal venous system and which poses a highly dangerous situation ending in gangrene of the bowel wall, the symptoms of an acute occlusion of the portal venous system are quite unspecific. To rule out an acute arterial occlusion, diagnostic evaluation has to be carried out quickly in order to decide on the necessity of therapeutic steps concerning a recanalization of the occluded vessels. Only few therapeutic options are available to recanalize and remodel the portal venous system, depending on the underlying disease, the age of the occlusion, its extension, and the effect on the bowel wall, stomach, spleen, and abdominal wall. Moreover, the efficacy of recanalization procedures mainly depends on the formation and number of collateral venous blood supply, its degree, and the anatomic structure. Possible complications of portal hypertension like varices, gastrointestinal vasculopathy, ascites, and splenomegaly also influence the success of recanalization procedures. Only in cases of acute thrombotic occlusion systemic lytic therapy promises to be successful. Therefore, other options such as transjugular intrahepatic recanalization, e.g. by means of the TIPS (transjugular intrahepatic portosystemic shunt) procedure, have to be evaluated.

Methods

Review of the literature.

Results

Noninvasive methods such as ultrasound (US), computed tomography, and especially magnetic resonance imaging (MRI) allow the evaluation of therapeutic options as well as their success, the feasibility of technical procedures, the detection of possible risks, and a calculation of risks and benefits.

Conclusion

In order to arrive at the correct therapeutic decision, a combination of MRI and US methods combined with color Doppler guarantee the most efficient diagnostic results in cases with acute or chronic occlusions of the portal venous system.

Differentiating malignant from benign thrombosis in hepatocellular carcinoma: contrast-enhanced ultrasound

BACKGROUND

To determine the accuracy of contrast-enhanced ultrasonography (CEUS) in differentiating malignant and benign venous thrombosis complicating hepatocellular carcinoma (HCC).

METHODS

Fifty patients (M:F = 41:9; age range 46-83 years) with HCC and venous thrombosis [portal vein (PV) in 45 and hepatic vein (HV) in 5] detected on CT or MR scan were evaluated with CEUS. Reference standard of malignant and benign thrombosis was based on serial clinicoradiologic follow-up (n = 43) or pathology (n = 7). Two independent, blinded readers retrospectively recorded the enhancement features of the venous thrombosis and diagnosed as benign or malignant thrombosis with a five-point confidence scale. Receiver operating characteristic (ROC) curves were calculated to determine the diagnostic performance of CEUS in differentiating malignant from benign thrombosis. Confidence level ratings were also used to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the diagnosis of malignant thrombosis. Inter-reader agreement was calculated using κ statistics in each assessed finding. Gray scale and Doppler characteristics of primary tumor and thrombosis were also assessed.

RESULTS

Of the 50 patients, 37 were malignant (33 with PV thrombosis and 4 with HV thrombosis) and 13 were benign (12 with PV thrombosis and 1 with HV thrombosis). In ROC curve analysis for differentiating malignant from benign thrombosis, Az was 0.947 (CI 0.841-0.991) for reader 1 and 0.958 (CI 0.861-0.995) for reader 2 with excellent inter-reader agreement (κ = 0.86). When the confidence level ratings of 1 or 2 were considered malignant thrombosis, the sensitivity, specificity, PPV, and NPV in differentiating malignant from benign thrombosis were 100%, 83%, 95%, and 100% for reader 1 and 100%, 92%, 97%, and 100% for reader 2.

CONCLUSION

CEUS is useful to differentiate malignant and benign venous thrombosis associated with HCC with high diagnostic accuracy.

Feasibility and long-term evolution of TIPS in cirrhotic patients with portal thrombosis

AIM

Many researchers consider portal thrombosis (PT) as a contraindication to transjugular intrahepatic portosystemic shunt (TIPS). The aim of this retrospective study was to compare the feasibility and long-term prognosis of TIPS in cirrhotic patients, with and without, complete PT.

PATIENTS AND METHODS

Four hundred and thirty-six consecutive cirrhotic patients with portal hypertension were referred for TIPS, between 1990 and 2004. These patients were divided into two groups according to their portal patency. PT+: 34 patients with complete PT with cavernoma (19) or without (15) cavernoma versus PT-: 402 patients with normal portal patency (308) and partial PT (94). Epidemiological data were compared using the chi and Student's t-tests, and comparative evolution was made from actuarial data using the log-rank test.

RESULTS

PT+ patients were more frequently women with viral hepatitis, and TIPS was performed more often for bleeding indications. The TIPS success rate was significantly lower in the PT+ group (79%) than in the PT- group (99.5%) (P<10). Presence of a cavernoma decreased the success rate to 63%. TIPS was always feasible in cases of recent PT and portal cavernoma with an accessible intrahepatic patent portal branch. Early and late outcome and complications were not significantly different between the two groups.

CONCLUSION

Complete PT does not modify TIPS' long-term outcome. Rather than a contraindication, PT should be considered as an indication for TIPS in cirrhotic patients with accessible intrahepatic portal vein. Further randomized studies should be planned in cirrhotic patients with recent PT to better qualify TIPS and anticoagulation indications, respectively.

Sonographic evaluation of vessel grafts in living donor liver transplantation recipients of the right lobe

AIM

To evaluate the vessel grafts (VG) used to reconstruct the middle hepatic vein (MHV) tributaries with ultrasonography.

METHODS

Twenty-four patients undergone living donor liver transplantation were enrolled in our study. MHV tributaries larger than 5 mm in diameter were reconstructed with interposition VG. Blood flow of the graft and interposition VG was checked by Doppler ultrasonography daily in the first 2 postoperative weeks and monthly followed up after discharge. The sensitivity of VG detected by ultrasonography was assessed using surgical records as references. Student's t test was used to compare the velocity of VG and occluded VG in chronic patents (> 3 mo).

RESULTS

Thirty-one VG were used to reconstruct the MHV tributaries. Ultrasonography identified 96.7% (30/31) of large MHV tributaries and 90.3% (28/31) of VG. The diameter of VG was 5.6 +/- 0.8 mm and the velocity of VG was 19.7 +/- 8.1 cm/s. Two VG (2/31, 6.5%) were occluded on the first postoperative day in one patient who suffered from persistent ascites and had a prolonged recovery of liver function. Twenty-six VG (26/31, 83.9%) were patent 2 wk after operation. Six (6/31, 19.4%) VG were patent over 3 mo after operation. Intrahepatic venous collaterals were detected in 29.2% (7/24) patients. The velocity of VG and occluded VG was 30.1 +/- 5.6 cm/s, 16.5 +/- 5.8 cm/s, respectively, in chronic patents. The difference between two groups was statistically significant (P < 0.001).

CONCLUSION

Our results indicate that most VG are patent in the first postoperative week while only a small portion with a higher velocity remains patent after 3 mo. Intrahepatic venous collaterals can be observed in some patients after occlusion of VG.

Implantable sensor for blood flow monitoring after transplant surgery

A limited number of techniques are employed in clinical medicine for regional tissue perfusion assessment. These methods are marginally effective and are not well suited for implantation due to the inability to miniaturize the associated technologies. Consequently, no standardized techniques exist for real-time, continuous monitoring of organ perfusion following transplantation. In this paper, a brief overview of the relevant clinical techniques employed for regional tissue perfusion assessment is given with particular emphasis on post-surgical monitoring of transplanted organs. The ideal characteristics for a perfusion monitoring system are discussed and the development of a new, completely implanted local tissue monitoring system is summarized. <I>In vivo</I> and <I>in vitro</I> data are presented that establish the efficacy of this new technology, which is a photonics-based sensor system uniquely suited for continuous tissue monitoring and real-time data reporting. The suitablity of this sensor technology for miniaturization, which enables implantation for monitoring localized tissue perfusion, is discussed.

Clinical utility of microbubble contrast-enhanced ultrasound in the diagnosis of hepatic artery occlusion after liver transplantation

To evaluate the frequency of use and the diagnostic accuracy of real-time contrast-enhanced ultrasound (CEUS) in the diagnosis of hepatic artery occlusion after liver transplantation. One hundred and fifty-two liver transplantations in 142 adult subjects, comprising 80 male patients and 62 female patients, were studied. After surgery, liver circulation was routinely assessed by conventional Doppler ultrasound (US). Wherever the examiners were not confident about the state of the circulation, CEUS was performed with one or more doses of a sulfur hexafluoride (SF-6)-containing second-generation contrast agent intravenously. Clinical follow up including repeat Doppler US, computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) of the liver vasculature were used as reference standards. During the first month after transplantation, Doppler US was inconclusive with regard to patency of the hepatic artery (HA) circulation in 20 (13 %) of 152 transplantations. CEUS was performed in these patients, and detected six cases of HA thrombosis (HAT) in five transplants. CEUS correctly ruled out HA occlusion in 15 transplants. All HA occlusions occurred during the first 14 days after transplantation. In the subset of transplantations examined with CEUS, the sensitivity, specificity and accuracy of CEUS were 100%. In approximately 13% of cases, conventional Doppler US did not provide sufficient visualization of the HA after liver transplantation. In these cases, correct diagnosis was achieved by supplementary CEUS.

Contrast-enhanced ultrasonography and spiral computed tomography in the detection and characterization of portal vein thrombosis complicating hepatocellular carcinoma

The aim was to compare the performances of contrast-enhanced (CE) ultrasonography (US) and spiral computed tomography (CT) in the detection and characterization of portal vein thrombosis complicating hepatocellular carcinoma (HCC). We studied 50 patients with HCC who had biopsy-proven portal vein thrombi that had been detected with US and color Doppler US. Thirteen of the thrombi involved the main portal trunk and 37 the segmental branches. CEUS and CT were performed within a week of thrombus biopsies. For each imaging technique, diagnoses of thrombosis (present/absent) and thrombus nature (malignancy/benignancy) were made by experienced readers under blinded conditions and compared with pathological findings to determine accuracy rates for thrombus detection and characterization. Forty-four of the 50 thrombi were pathologically diagnosed as malignant and the remaining six were benign. CEUS detected 50/50 (100%) thrombi and correctly characterized 49/50 (98%). CT detected 34/50 (68%) thrombi and correctly characterized 23 of these 34 (68%). CEUS outperformed CT in terms of both thrombus detection (P < 0.0001) and characterization (P = 0.0001). CEUS appears to be significantly superior to CT for detection and characterization of portal vein thrombosis complicating HCC, and it should be considered in the staging of these tumors.

Contrast-enhanced ultrasound with SonoVue in the evaluation of postoperative complications in pediatric liver transplant recipients

PURPOSE

To evaluate the utility of contrast-enhanced sonography in the study of pediatric liver transplant recipients and its potential impact in reducing the need for invasive diagnostic procedures.

MATERIALS AND METHODS

From October 2002 to December 2003 we performed routine color Doppler ultrasound and contrast-enhanced ultrasound studies on 30 pediatric patients who had undergone liver transplantation. Findings indicative of complications were confirmed with invasive studies (angiography, computed tomography, and PTC).

RESULTS

Contrast-enhanced sonography correctly identified four of the five cases of hepatic artery thrombosis and all those involving the portal (n = 6) and hepatic vein (n = 3) thrombosis. It failed to identify one case of hepatic artery thrombosis characterized by collateral circulation arising from the phrenic artery and the single case of hepatic artery stenosis. The latter was more evident on color Doppler, which revealed a typical tardus parvus waveform. The use of contrast offered no significant advantages in the study of biliary complications although it did provide better visualization of bile leaks.

CONCLUSIONS

Contrast-enhanced sonography improves diagnostic confidence and reduces the need for more invasive imaging studies in the postoperative follow-up of pediatric liver transplant recipients.

Diagnosis of benign and malignant portal vein thrombosis in cirrhotic patients with hepatocellular carcinoma: color Doppler US, contrast-enhanced US, and fine-needle biopsy

BACKGROUND

We assessed the role of contrast-enhanced ultrasound (CEUS) in the differential diagnosis between benign and malignant portal vein thrombosis in patients who had cirrhosis with hepatocellular carcinoma (HCC).

METHODS

Fifty-four consecutive patients who had cirrhosis, biopsy-proved HCC, and thrombosis of the main portal vein and/or left/right portal vein on US were prospectively studied with color Doppler US (CDUS) and CEUS. CEUS was performed at low mechanical index after intravenous administration of a second-generation contrast agent (SonoVue, Bracco, Milan, Italy). Presence or absence of CDUS signals or thrombus enhancement on CEUS were considered diagnostic for malignant or benign portal vein thrombosis. Twenty-eight patients also underwent percutaneous portal vein fine-needle biopsy (FNB) under US guidance. All patients were followed-up bimonthly by CDUS. Shrinkage of the thrombus and/or recanalization of the vessels on CDUS during follow-up were considered definitive evidence of the benign nature of the thrombosis, whereas enlargement of the thrombus, disruption of the vessel wall, and parenchymal infiltration over follow-up were considered consistent with malignancy. CDUS, CEUS, and FNB results were compared with those at follow-up.

RESULTS

Follow-up (4 to 21 months) showed signs of malignant thrombosis in 34 of 54 patients. FNB produced a true-positive result for malignancy in 19 of 25 patients, a false-negative result in six of 25 patients, and a true-negative result in three of three patients. CDUS was positive in seven of 54 patients. CEUS showed enhancement of the thrombus in 30 of 54 patients. No false-positive result was observed at CDUS, CEUS, and FNB. Sensitivities of CDUS, CEUS, and FNB in detecting malignant thrombi were 20%, 88%, and 76% respectively. Three patients showed negative CDUS and CEUS and positive FNB results; follow-up confirmed malignant thrombosis in these patients. One patient showed negative CDUS, CEUS, and FNB findings. However, follow-up of the thrombus showed US signs of malignancy. Another FNB confirmed HCC infiltration of the portal vein.

CONCLUSION

CEUS seems to be the most sensitive and specific test for diagnosing malignant portal vein thrombosis in patients with cirrhosis.

Thrombosis of the portal venous system

Portal vein thrombosis (PVT) is a rare cause of portal hypertension. Its diagnosis has been facilitated by improvements in imaging techniques, in particular Doppler sonography. The prevalence is about 1% in the general population, but much higher rates are observed in patients with hepatic cirrhosis (7%, range 0.6-17%), particularly those who also have hepatocellular carcinoma (HCC) (35%). The most common causes of PVT are myeloproliferative disorders, deficiencies of anticoagulant proteins, prothrombotic gene mutations, cirrhosis with portal hypertension, and HCC. Its development often requires the presence of two or more risk factors (local and/or systemic), e.g., a genetically determined thrombophilic state plus an infectious episode or abdominal surgery. It is clinically useful to distinguish between cirrhotic and noncirrhotic forms. Portal vein thrombosis is also traditionally classified as acute or chronic, but this distinction is often difficult. Color Doppler ultrasound is the first-line imaging study for diagnosis of PVT; magnetic resonance angiography and CT angiography are valid alternatives. The main complications are ischemic intestinal necrosis (in acute PVT) and esophageal varices (in chronic cases); the natural history of the latter differs depending on whether or not the thrombosis is associated with cirrhosis. The treatment of choice for PVT has never been adequately investigated. It is currently based on the use of anticoagulants associated, in some cases, with thrombolytics, but experience with the latter agents is too limited to draw any definite conclusions. In chronic thrombosis (even forms associated with cirrhosis), anticoagulant therapy is recommended and possibly, beta-blockers as well. Naturally, treatment of the underlying pathology is essential.

Prospective evaluation of vascular complications after liver transplantation: comparison of conventional and microbubble contrast-enhanced US

PURPOSE

To prospectively compare diagnostic performance of conventional Doppler ultrasonography (US) and microbubble contrast material-enhanced US for assessment of vascular complications after liver transplantation, with clinical follow-up or angiography as reference standard.

MATERIALS AND METHODS

This study was approved by institutional review board and was HIPAA compliant. Written informed consent was obtained. Seventy-two patients (49 men, 23 women; average age, 52.3 years) were included in this study. Patients who had undergone liver transplantation underwent conventional color Doppler and contrast-enhanced US of the liver. Quality of hepatic artery (HA) and portal vein (PV) visualization, contrast material arrival time, and time for complete evaluation of vasculature were compared for both techniques. McNemar test was used to compare vascular flow visualization scores; Student t test was used to compare mean study times with both techniques. Patients without HA flow at Doppler US underwent angiography; those with flow were followed up clinically. McNemar test was used to compare sensitivity of both techniques.

RESULTS

Contrast-enhanced US helped significantly improve flow visualization in hepatic vessels (P < .001). Mean contrast material arrival time was 13.7 seconds +/- 3.8 (standard deviation) in proper HA and 20.7 seconds +/- 6.3 in PV. Mean study time decreased from 27.4 minutes +/- 13.9 to 9.3 minutes +/- 4.5 (P < .01). Doppler US failed to depict HA flow in eight patients; contrast-enhanced US showed flow in six and no flow in two of these patients. Follow-up results confirmed contrast-enhanced US findings. Sensitivity, specificity, and accuracy for Doppler US were 91.3%, 100%, and 91.5%, respectively. Sensitivity, specificity, and accuracy of contrast-enhanced US were all 100%. Sensitivity and accuracy values of the two techniques were significantly different (P < .014); there was no significant difference in specificity (P > .99)

CONCLUSION

Contrast-enhanced US helped improve flow visualization in the HA and PV, decrease scanning time, and correctly differentiate between thrombosis and a patent artery in patients without HA flow at conventional Doppler US.

Contrast-enhanced versus conventional and color Doppler sonography for the detection of thrombosis of the portal and hepatic venous systems

OBJECTIVE

We conducted a prospective study to compare sonography, color Doppler sonography, and contrast-enhanced sonography for the detection and characterization of portal and hepatic vein thrombosis complicating hepatic malignancies.

SUBJECTS AND METHODS

Three hundred sixteen patients with biopsy-proved hepatic tumors were studied at baseline and 3 months later with sonography, color Doppler sonography, and contrast-enhanced sonography. Thrombosis was defined as the presence of intraluminal echogenic material at sonography, absence of intraluminal color signals at color Doppler sonography, and presence of nonenhancing intraluminal area at contrast-enhanced sonography. Thrombi were considered malignant if they displayed continuity with tumor tissue at sonography, intrathrombus color signals at color Doppler sonography, and enhancing signals at contrast-enhanced sonography, both having arterial waveforms at Doppler spectral examination. Definitive diagnoses were obtained by sonographically guided biopsy except for thrombi displaying at conventional sonography unequivocal continuity with tumor tissue.

RESULTS

Thrombosis was detected in 79 (25.0%) of 316 patients at baseline and in 83 (26.3%) of 316 patients after 3 months. Eighty-one (97.6%) of the 83 thrombi were malignant. Definitive diagnosis was performed by imaging in 60 (72.3%) of the 83 cases and by biopsy in 23 cases (27.7%). For thrombus detection, contrast-enhanced sonography displayed significantly higher sensitivity than color Doppler sonography (p = 0.004) and borderline superiority over sonography (p = 0.058). For thrombus characterization, contrast-enhanced sonography was significantly more sensitive than color Doppler sonography (p < 0.0005) and conventional sonography (p = 0.02).

CONCLUSION

Contrast-enhanced sonography is superior to sonography and color Doppler sonography for the detection and characterization of portal and hepatic vein thrombosis complicating hepatic malignancies.

Diagnostic efficacy of SonoVue®, a second generation contrast agent, in the assessment of extracranial carotid or peripheral arteries using colour and spectral Doppler ultrasound: a multicentre study

The purpose of this study was to demonstrate the improvement in diagnostic quality and diagnostic accuracy of SonoVue microbubble contrast-enhanced ultrasound (CE-US) versus unenhanced ultrasound imaging during the investigation of extracranial carotid or peripheral arteries. 82 patients with suspected extracranial carotid or peripheral arterial disease received four SonoVue doses (0.3 ml, 0.6 ml, 1.2 ml and 2.4 ml) with Doppler ultrasound performed before and following each dose. Diagnostic quality of the CE-US examinations was evaluated off-site for duration of clinically useful contrast enhancement, artefact effects and percentage of examinations converted from non-diagnostic to diagnostic. Accuracy, sensitivity and specificity were assessed as agreement of CE-US diagnosis evaluated by an independent panel of experts with reference standard modality. The median duration of clinically useful signal enhancement significantly increased with increasing SonoVue doses (p< or =0.002). At the dose of 2.4 ml of SonoVue, diagnostic quality evaluated as number of inconclusive examinations significantly improved, falling from 40.7% at baseline down to 5.1%. Furthermore, SonoVue significantly (p<0.01) increased the accuracy, sensitivity and specificity of assessment of disease compared with baseline ultrasound. SonoVue increases the diagnostic quality of Doppler images and improves the accuracy of both spectral and colour Doppler examinations of extracranial carotid or peripheral arterial disease.

Aggressive surgical resection for carcinoma of gallbladder

BACKGROUND

The aim of the present study was to review the long-term result of patients with carcinoma of gallbladder with adequate investigations and aggressive surgical resection.

METHODS

A retrospective study was carried out on patients with carcinoma of gallbladder treated at the Division of Hepatopancreatobiliary Surgery, the Chinese University of Hong Kong from January 1997 to December 2002.

RESULTS

Of the 47 patients with carcinoma of gallbladder, 28 patients were treated symptomatically because they were found to have metastatic disease (n = 22), unresectable disease (n = 2) or poor associated medical disease (n = 4). One patient had carcinoma in-situ after laparoscopic cholecystectomy. No further treatment was considered necessary. The remaining 18 patients (38.3%) came to laparotomy after preoperative investigations with ultrasonography, computed tomography, endoscopic or percutaneous cholangiography, and visceral angiography. Laparoscopy and laparoscopic ultrasound were used in the later part of the study. Radical cholecystectomy was carried out in 14 patients (77.8%). The in-hospital mortality rate was 5.3% and the surgical morbidity was 31.6%. The remaining four patients underwent palliative cholecystectomy because of the extent of the disease. The overall 5-year survival for the 47 patients was 19.1%, for the 18 patients who came to laparotomy was 44.4%, and for the 14 patients who underwent resection with curative intent was 57.1%.

CONCLUSIONS

With adequate preoperative investigations, and the use of laparoscopy and laparoscopic ultrasound, radical resection was possible in the majority of patients who came to laparotomy for carcinoma of gallbladder. Aggressive radical resection gave good results.

Imaging and radiological interventions of portal vein thrombosis

Portal vein thrombosis (PVT) is diagnosed by imaging methods. Once diagnosed by means of ultrasound, Doppler ultrasound can be performed to distinguish between a benign and malignant thrombus. If further information is required, magnetic resonance angiography or contrast-enhanced computed tomography is the next step, and if these tests are unsatisfactory, digital subtraction angiography should be performed. Many papers have been published dealing with alternative methods of treating PVT, but the material is fairly heterogeneous. In symptomatic non-cavernomatous PVT, recanalization using local methods is recommended by many authors. Implantation of transjugular intrahepatic portosystemic shunt is helpful in cirrhotic patients with non-cavernomatous PVT in reducing portal pressure and in diminishing the risk of re-thrombosis. In noncirrhotic patients with recent PVT, some authors recommend anticoagulation alone. In chronic thrombotic occlusion of the portal vein, local measures may be implemented if refractory symptoms of portal hypertension are evident.

Transaminitis after pancreatic islet transplantation

BACKGROUND

An asymptomatic, self-limited transaminitis uniformly follows pancreatic islet transplantation (PIT) performed through portal vein (PV) infusion. The underlying cause and significance of this transaminitis is unclear.

STUDY DESIGN

Records of all patients with insulin-dependent diabetes mellitus who had undergone PIT at our institution were reviewed. All PITs were performed in conjunction with a remote pancreatic islet isolation center and done through percutaneous transhepatic PV infusion. Alanine aminotransferase (ALT) levels, serum glucose concentrations, insulin requirements, and color-flow Doppler ultrasonography examinations of the right upper quadrant were assessed before and after PIT.

RESULTS

Eleven patients have undergone a total of 26 PITs. An elevated ALT level occurred in all 11 patients (100%) after the first PIT, with the median post-PIT peak ALT level reaching 187 IU/L. Transaminitis was less frequent and less marked after the second PIT. A negative correlation between viability of the pancreatic islets transplanted (r = -0.44, p = 0.03) and a positive correlation between the ratio of maximum to initial PV pressure (r = 0.41, p = 0.04) were seen with the subsequent ALT peak. Color-flow Doppler ultrasonography examinations showed no occurrences of PV thrombosis or intrahepatic hematoma. Finally, the degree of transaminitis did not correlate with post-PIT insulin requirements, indicating that post-PIT transaminitis cannot be used to measure allograft rejection or function.

CONCLUSIONS

Transaminitis after PIT is common and self-limited. Post-PIT transaminitis does not signal acute rejection or serious procedure-related complications such as PV thrombosis or intrahepatic hematoma.

Contrast enhanced ultrasound in liver imaging

Ultrasound contrast agents were originally introduced to enhance the Doppler signals when detecting vessels with low velocity flow or when imaging conditions were sub-optimal. Contrast agents showed additional properties, it was discovered that a parenchymal enhancement phase in the liver followed the enhancement of the blood pool. Contrast agents have made ultrasound scanning more accurate in detection and characterization of focal hepatic lesions and the sensitivity is now comparable with CT and MRI scanning. Further, analysis of the transit time of contrast agent through the liver seems to give information on possible hepatic involvement, not only from focal lesions but also from diffuse benign parenchymal disease. The first ultrasound contrast agents were easily destroyed by the energy from the sound waves but newer agents have proved to last for longer time and hereby enable real-time scanning and make contrast enhancement suitable for interventional procedures such as biopsies and tissue ablation. Also, in monitoring the effect of tumour treatment contrast agents have been useful. A brief overview is given on some possible applications and on different techniques using ultrasound contrast agents in liver imaging. At present, the use of an ultrasound contrast agent that allows real-time scanning with low mechanical index is to be preferred.

Preoperative preparation of patients with advanced liver disease

OBJECTIVE

To review the characteristic features of patients with advanced liver disease that may lead to increased perioperative morbidity and mortality rates.

DESIGN

Literature review.

RESULTS

Patients with end-stage liver disease are at high risk of major complications and death following surgery. The most common complications are secondary to acute liver failure and include severe coagulopathy, encephalopathy, adult respiratory distress syndrome, acute renal failure, and sepsis. The degree of malnutrition, control of ascites, level of encephalopathy, prothrombin time, concentration of serum albumin, and concentration of serum bilirubin predict the risk of complications and death following surgery. Other determinants of adverse outcome include emergency surgery, advanced age, and cardiovascular disease. Portal hypertension is a prominent feature of advanced liver disease, and it predisposes the patient to variceal hemorrhage, hepatorenal syndrome, hepatopulmonary syndrome, and uncontrolled ascites. Portal hypertension can be ameliorated by percutaneous or surgical portasystemic shunting procedures. If well-defined contraindications are not present, patients with advanced liver disease should be evaluated for orthotopic liver transplantation from a cadaver donor or possible living-related liver transplantation.

CONCLUSIONS

Optimal preparation, which addresses the common features of advanced liver disease, may decrease the risk of complications or death following surgery. Preparation should include correcting coagulopathy, minimizing preexisting encephalopathy, preventing sepsis, and optimizing renal function.

Endoscopic ultrasound is a sensitive and specific test to diagnose portal venous system thrombosis (PVST)

OBJECTIVES

Thrombosis of the portal venous system (PVS) may complicate cirrhosis, pancreatitis, malignancies, and hypercoagulable states. Computed tomography (CT) scanning can diagnose thrombi present in the lumen of the PVS, but is probably insensitive. Endoscopic ultrasound (EUS) may be a more sensitive test for diagnosing PVS thrombosis (PVST). We sought to determine the accuracy of EUS for the diagnosis of PVST.

METHODS

Using a retrospective analysis of patients' studies retrieved from a database at Massachusetts General Hospital, we determined the sensitivity and specificity of EUS in 16 patients with PVST and 29 without PVST as proven by surgery and/or CT scanning. All patients underwent a linear EUS exam of the PVS and the results of the EUS report were used as the basis of the study.

RESULTS

The sensitivity of EUS for the finding of PVST was 81% in 13 of 16 patients and the specificity was 93% in 27 of 29 patients with an overall accuracy of 89% (40/45). In an additional group of 11 patients, EUS demonstrated the presence of a PVST that was not detected by CT scanning.

CONCLUSION

Linear EUS is a highly sensitive and specific test for PVST.

Three-dimensional contrast-enhanced MR angiography in diagnosis of portal vein involvement by hepatic tumors

AIM: To assess the accuracy of three-dimensional contrast-enhanced magnetic resonance angiography (3D CE MRA) in evaluation of the portal vein involvement in patients with hepatic tumors.

METHODS: 3D CE MRA was performed in 62 patients with hepatic tumors to assess the patency of the main, right and left portal veins before hepatic surgery. A total of 186 veins were examined for encasement, occlusion and tumor thrombosis. The results of 3D CE MRA diagnosis were then correlated with the surgical-pathological and intra-operative sonographic findings.

RESULTS: 3D CE MRA correctly detected 48 of 49 involved and 135 of 137 noninvolved portal veins with the sensitivity of 98%, specificity of 99%, positive predictive value of 96% and negative predictive value of 99%.

CONCLUSION: 3D CE MRA is accurate in evaluation of the portal vein involvement in patients with hepatic tumors.