Role of contrast-enhanced 3D magnetic resonance portography in evaluating portal venous system compared with color Doppler ultrasonography

Venous Thrombosis in Acute Pancreatitis: What to and Not to Do?

Acute pancreatitis is an acute inflammatory condition of the pancreas that has not only local but systemic effects as well. Venous thrombosis is one such complication which can give rise to thrombosis of the peripheral vasculature in the form of deep vein thrombosis, pulmonary embolism, and splanchnic vein thrombosis. The prevalence of these complications increases with the severity of the disease and adds to the adverse outcomes profile. With better imaging and awareness, more cases are being detected, although many at times it can be an incidental finding. However, it remains understudied and strangely, most of the guidelines on the management of acute pancreatitis are silent on this aspect. This review offers an overview of the incidence, pathophysiology, symptomatology, diagnostic work-up, and management of venous thrombosis that develops in AP.

Comparison of unenhanced and contrast-enhanced 3 T magnetic resonance portovenography in children with extra hepatic portal venous obstruction

PURPOSE

To evaluate role of 3-T magnetic resonance portovenography (MRPV) in children with extra hepatic portal venous obstruction (EHPVO) and compare unenhanced and contrast-enhanced sequences.

METHODS

20 Children with EHPVO underwent MRPV using unenhanced [T2, T1 pre-contrast, Balanced turbo field echo (BTFE)] and contrast-enhanced (CE) modified DIXON (mDIXON) sequences. The images were evaluated for the patency of abdominal veins, hepatic and splenic parenchyma by two radiologists for interobserver agreement.

RESULTS

BTFE and post-contrast mDIXON sequences performed best for evaluation of abdominal veins. Concordance between the BTFE and CE sequences was good to very good for both the radiologists for splenic vein (SV) evaluation. The concordance between the two sequences for evaluation of superior mesenteric vein and its confluence with the SV was less remarkable and varied from fair to good, while the interobserver agreement was very good to perfect. The interobserver agreement between the BTFE and CE sequence for the evaluation of left renal vein was very good, while that for IVC was perfect. The agreement between BTFE and CE sequence was perfect for the evaluation of right and middle hepatic veins, while the interobserver agreement was good to perfect. The interobserver agreement was poor for evaluation of hepatic parenchyma on BTFE sequence as compared to CE sequence, and moderate for splenic parenchyma.

CONCLUSION

BTFE sequence is the single best unenhanced MR pulse sequence to detect all the vascular structures in children with EHPVO. CE-MRI is not superior to BTFE sequence and should be used at the discretion of the radiologist.

Impact of sustained virologic response on short-term clinical outcomes in hepatitis C-related cirrhosis

BACKGROUND

Hepatitis C virus (HCV) is a common cause of cirrhosis, leading to increased morbidity and mortality. Treatment of the underlying etiology has been shown to improve fibrosis and cirrhosis.

AIM

We sought to evaluate the impact of a sustained virologic response on liver chemistries, model for end stage liver disease (MELD) score, Child-Pugh-Turcotte score (CPT), and fibrosis 4 score (FIB4) in patients with liver cirrhosis secondary to HCV with portal hypertension, with or without decompensation.

METHODS

Patients with HCV seen in our transplant clinic between June 2013 and September 2015 were identified using ICD-9 code 573.3. Charts were reviewed retrospectively.

RESULTS

We collected data from 92 patients with a mean pretreatment MELD score of 9.16±2.98. The most common genotype was Ia, n=79 (86%). The mean duration of follow-up was 7.52±2.25 months. Transaminitis improved significantly at follow-up versus pretreatment [mean aspartate transaminase from 81.2±62.9 to 32.4±12.0 (P<0.0001); alanine transaminase 74.7±77.8 to 27.7±19.4 (P<0.0001)]. Albumin, bilirubin, and α-fetoprotein improved significantly. MELD scores improved in patients with pretreatment scores greater than 10 (P<0.0003), but not in patients with pretreatment scores less than 10 (P=0.501). The CPT score decreased from 6.1±0.9 to 5.8±0.9 (P<0.0024). The FIB4 score improved significantly in patients with baseline FIB4 more than 3.24, but not with higher baseline FIB4.

CONCLUSION

Use of direct antivirals in patients with decompensated cirrhosis because of HCV leads to improved MELD, FIB4, and CPT scores.

Left Gastric Vein Visualization with Hepatopetal Flow Information in Healthy Subjects Using Non-Contrast-Enhanced Magnetic Resonance Angiography with Balanced Steady-State Free-Precession Sequence and Time-Spatial Labeling Inversion Pulse

Objective

To selectively visualize the left gastric vein (LGV) with hepatopetal flow information by non-contrast-enhanced magnetic resonance angiography under a hypothesis that change in the LGV flow direction can predict the development of esophageal varices; and to optimize the acquisition protocol in healthy subjects.

Materials and Methods

Respiratory-gated three-dimensional balanced steady-state free-precession scans were conducted on 31 healthy subjects using two methods (A and B) for visualizing the LGV with hepatopetal flow. In method A, two time-spatial labeling inversion pulses (Time-SLIP) were placed on the whole abdomen and the area from the gastric fornix to the upper body, excluding the LGV area. In method B, nonselective inversion recovery pulse was used and one Time-SLIP was placed on the esophagogastric junction. The detectability and consistency of LGV were evaluated using the two methods and ultrasonography (US).

Results

Left gastric veins by method A, B, and US were detected in 30 (97%), 24 (77%), and 23 (74%) subjects, respectively. LGV flow by US was hepatopetal in 22 subjects and stagnant in one subject. All hepatopetal LGVs by US coincided with the visualized vessels in both methods. One subject with non-visualized LGV in method A showed stagnant LGV by US.

Conclusion

Hepatopetal LGV could be selectively visualized by method A in healthy subjects.

Approach to thrombosis at unusual sites: Splanchnic and cerebral vein thrombosis

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are two manifestations of unusual site venous thromboembolism (VTE). SVT includes thrombosis in the portal, mesenteric or splenic veins, and the Budd-Chiari syndrome. CVT encompasses thrombosis of the dural venous sinuses and thrombosis of the cerebral veins. Unusual site VTE often represents a diagnostic and therapeutic challenge because of the heterogeneity in clinical presentation, the limited evidence available in the literature on the acute and long-term prognosis of these diseases, and the lack of large randomized controlled trials evaluating different treatment options. This narrative review describes the approach to patients with SVT or CVT by examining the diagnostic process, the assessment of potential risk factors and the appropriate anticoagulant treatment.

Clinical manifestations and imaging tools in the diagnosis of splanchnic and cerebral vein thromboses

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are uncommon manifestation of venous thromboembolism (VTE), occurring less frequently than deep vein thrombosis of the lower extremities and pulmonary embolism. SVT encompasses portal vein thrombosis, mesenteric vein thrombosis, splenic vein thrombosis and the Budd-Chiari syndrome. It is therefore a heterogeneous disease, with differences in clinical manifestations according to the site of thrombosis. CVT includes thrombosis of the cortical or deep cerebral veins and thrombosis of the major dural venous sinuses. Clinical presentation is variable, with a wide spectrum of signs and symptoms that can mimic other cerebral diseases. There are no clinical algorithms or specific laboratory tests that can guide in the identification of SVT and CVT; therefore, the diagnosis relies exclusively on imaging tests. Conventional angiography once was the gold standard for the diagnosis of SVT and CVT, but it is rarely used nowadays. Abdominal ultrasound (US), computed tomography (CT) and magnetic resonance (MR) with angiography are currently used for the diagnosis of SVT; while cerebral CT and MR with angiography are currently used for the diagnosis of CVT. These imaging tests have different sensitivities/specificities and different advantages/disadvantages that should be kept into consideration when choosing the appropriate imaging test based on the suspected site of thrombosis. This narrative review summarizes the clinical and diagnostic approach to SVT and CVT.

Extrahepatic Portal Vein Obstruction in Children: Role of Preoperative Imaging

Aim:

Extrahepatic portal vein obstruction (EHPVO) is characterized by features of recent thrombosis or portal hypertension with portal cavernoma as a sequel of portal vein obstruction. Imaging of spleno-portal axis is the mainstay for the diagnosis of EHPVO. The aim of this study is to analyze the role of imaging in the preoperative assessment of the portal venous system in children with EHPVO.

Materials and Methods:

A hospital-based cross-sectional study was conducted on twenty children with EHPVO aged between 1 and 18 years over a period of 1 year. The children were evaluated clinically, followed by upper gastrointestinal endoscopy. Radiological assessment included imaging of the main portal vein, its right and left branches, splenic vein, and superior mesenteric vein using color Doppler ultrasonography (CDUSG) and magnetic resonance portovenogram (MRP). Evidence of portal biliopathy, status of collaterals, and possible sites for portosystemic shunt surgery were also examined.

Results:

All the patients presented in chronic stage with portal cavernoma and only one patient (5%) had bland thrombus associated with cavernoma. The CDUSG and MRPs had a sensitivity of 66.6-90% and 96.7% and specificity of 91.5% and 98.3% respectively with regard to the assessment of the extent of thrombus formation and flow in the portal venous system. Both the modalities were found to be complementary to each other in preoperative assessment of EHPVO. However, the sensitivity of MRP was slightly superior to CDUSG in detecting occlusion and identifying portosystemic collaterals and dilated intrahepatic biliary radicals.

Conclusion:

Results of the present study indicate that MRP is well suited and superior to CDUSG in the preoperative imaging of patients with EHPVO.

Portal venous system thrombosis complicating acute pancreatitis

Acute pancreatitis (AP) is an acute inflammatory disease of the pancreas characterized by local or systemic complications. Portal venous system thrombosis (PVT) is a relatively rare complication, which is often an incidental finding on contrast-enhanced computed tomography (CECT) performed to assess symptoms or local complications. If clinicians focus on AP while ignoring PVT, it may have serious clinical consequences. Previous studies on PVT complicating pancreatitis focused principally on chronic pancreatitis (CP) patients. Only a few single-center studies have been reported in foreign countries, and there are rare studies in China. For PVT complicating AP, there is still controversy over whether to implement anticoagulation therapy or not, suggesting the lack of a standardized treatment. This paper aims to explore the characteristics and treatment of PVT complicating AP and reviews the literature with an aim to raise awareness of this complication.

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.

Portal vein thrombosis

Portal vein thrombosis is an important cause of portal hypertension. PVT occurs in association with cirrhosis or as a result of malignant invasion by hepatocellular carcinoma or even in the absence of associated liver disease. With the current research into its genesis, majority now have an underlying prothrombotic state detectable. Endothelial activation and stagnant portal blood flow also contribute to formation of the thrombus. Acute non-cirrhotic PVT, chronic PVT (EHPVO), and portal vein thrombosis in cirrhosis are the three main variants of portal vein thrombosis with varying etiological factors and variability in presentation and management. Procoagulant state should be actively investigated. Anticoagulation is the mainstay of therapy for acute non-cirrhotic PVT, with supporting evidence for its use in cirrhotic population as well. Chronic PVT (EHPVO) on the other hand requires the management of portal hypertension as such and with role for anticoagulation in the setting of underlying prothrombotic state, however data is awaited in those with no underlying prothrombotic states. TIPS and liver transplant may be feasible even in the setting of PVT however proper selection of candidates and type of surgery is warranted. Thrombolysis and thrombectomy have some role. TARE is a new modality for management of HCC with portal vein invasion.

Imaging in clinical decision-making for portal vein thrombosis

Thrombosis of the portal venous system is a frequent and potentially life-threatening condition that can take place in a number of different clinical settings including liver cirrhosis, hepatocellular carcinoma, other solid tumours, abdominal septic foci, acute pancreatitis, haematological malignancies and congenital or acquired prothrombotic disorders. Clinical decision-making in patients with thrombosis of the portal venous system is a particularly complex process owing to the heterogeneity of the population affected by this condition and the lack of high-quality evidence from randomized controlled trials for the use of anticoagulation therapy in these patients. This Review discusses the available data regarding how imaging can provide assistance to physicians involved in this decision-making process in different clinical settings. A flowchart illustrating how to use imaging in this setting, based on current evidence and on the experience of the Vascular Liver Diseases Group of the Hospital Clinic in Barcelona, is also presented.

Splanchnic venous thrombosis and pancreatitis

Pancreatitis is an inflammatory process with local and systemic manifestations. One such local manifestation is thrombosis in splanchnic venous circulation, predominantly of the splenic vein. The literature on this important complication is very sparse. This review offers an overview of mechanism of thrombosis, its pathophysiology, diagnosis, and management in the setting of acute as well as chronic pancreatitis.

The diameter of the originating vein determines esophageal and gastric fundic varices in portal hypertension secondary to posthepatitic cirrhosis

OBJECTIVE

The aim of this study was to determine whether and how the diameter of the vein that gives rise to the inflowing vein of the esophageal and gastric fundic varices secondary to posthepatitic cirrhosis, as measured with multidetector-row computed tomography, could predict the varices and their patterns.

METHODS

A total of 106 patients with posthepatitic cirrhosis underwent multidetector-row computed tomography. Patients with and without esophageal and gastric fundic varices were enrolled in Group 1 and Group 2, respectively. Group 1 was composed of Subgroup A, consisting of patients with varices, and Subgroup B consisted of patients with varices in combination with portal vein-inferior vena cava shunts. The diameters of the originating veins of veins entering the varices were reviewed and statistically analyzed.

RESULTS

The originating veins were the portal vein in 8% (6/75) of patients, the splenic vein in 65.3% (49/75) of patients, and both the portal and splenic veins in 26.7% (20/75) of patients. The splenic vein diameter in Group 1 was larger than that in Group 2, whereas no differences in portal vein diameters were found between groups. In Group 1, the splenic vein diameter in Subgroup A was larger than that in Subgroup B. A cut-off splenic vein diameter of 8.5 mm achieved a sensitivity of 83.3% and specificity of 58.1% for predicting the varices. For discrimination of the varices in combination with and without portal vein-inferior vena cava shunts, a cut-off diameter of 9.5 mm achieved a sensitivity of 66.7% and specificity of 60.0%.

CONCLUSION

The diameter of the splenic vein can be used to predict esophageal and gastric fundic varices and their patterns.

MR evaluation of portal hypertensive collateral shunting vessels for predicting outcome after transjugular intrahepatic portosystemic shunt

PURPOSE

We assessed whether magnetic resonance (MR) imaging evaluation of portosystemic collateral shunts can aid prediction of therapeutic effectiveness and complications after creation of a transjugular portosystemic shunt (TIPS), and technical difficulty during the TIPS procedure.

MATERIALS AND METHODS

We retrospectively reviewed 32 patients (27 men, 5 women; mean age, 56.4 years) who underwent TIPS creation following gadolinium-enhanced MR examination. We measured the diameters of pre-existing portosystemic collateral shunting vessels, added the measurements together to generate a shunting collateral score for each patient, and divided patients into 2 groups by score of 4 or greater or less than 4. We then compared therapeutic effectiveness, technical difficulty and complications of the TIPS procedure, and portal venous (PV) pressure, PV-inferior vena cava (IVC) pressure gradient, and PV diameter between the groups.

RESULTS

The patients with a pre-existing large portosystemic shunt showed insignificant trends toward higher technical difficulty of the shunt procedure and rate of shunt dysfunction. The 2 groups showed no significant difference in early mortality rate, onset or worsening rate of hepatic encephalopathy after TIPS creation, PV pressure, PV-IVC pressure gradient, or PV diameter.

CONCLUSION

Gadolinium-enhanced MR imaging may help in predicting technical difficulty and complications of TIPS.

MR imaging evaluation of the hepatic vasculature

Assessment of the hepatic vasculature is essential for tumor staging, surgical planning, and understanding of liver disease. Technological advances have made contrast-enhanced magnetic resonance (MR) imaging comparable to multidetector-row computed tomography for diagnostic vascular imaging with respect to spatial resolution. Unenhanced MR angiographic sequences enable reasonable clinical assessment of vessels without contrast agents in patients with contraindications or renal insufficiency. Furthermore, MR angiography may be used to provide directional information through manipulation of the signal intensity of flowing blood. A major limitation to consistent contrast-enhanced MR angiography is the timing of MR image acquisition with arrival of the contrast bolus in the structures of interest. In this article, the authors discuss currently available techniques for imaging of the hepatic vasculature.

Survival among children with portal vein thrombosis and end-stage liver disease

Occlusive PVT concurrent with chronic liver disease is a common clinical entity among pediatric patients referred for transplantation. The natural history of PVT is unknown. Our aim was to determine, using a retrospective cohort design, if children under 13 yr with chronic liver disease and concomitant PVT have an increased mortality risk prior to and after transplantation. A total of 203 patients were included in the study. Nearly 10% of the population had PVT (n = 19); 63.2% of PVT patients (5.9% of total cohort) underwent liver transplantation (n = 12). PVT patients tended to be younger than non-PVT patients at evaluation (1.94 +/- 3.51 vs. 3.79 +/- 4.11, p = 0.059). Clinical and demographic factors were similar between the two groups. Regarding survival, four PVT patients died, of which two had undergone transplantation. Kaplan-Meier analyses indicated that PVT and non-PVT patients had similar survival from the time of evaluation, on the waiting list, and after transplant. Although limited by sample size, our study suggests that a diagnosis of PVT does not increase the mortality risk for children waiting for a liver transplant. Further study is needed to discern variations in mortality risk that may occur in the pediatric chronic liver disease population with PVT.

Review article: the modern management of portal vein thrombosis

BACKGROUND

Portal vein thrombosis (PVT) is an important cause of portal hypertension. It may occur as such with or without associated cirrhosis and hepatocellular carcinoma. Information on its management is scanty.

AIM

To provide an update on the modern management of portal vein thrombosis. Information on portal vein thrombosis in patients with and without cirrhosis and hepatocellular carcinoma is also updated.

METHODS

A pubmed search was performed to identify the literature using search items portal vein thrombosis-aetiology and treatment and portal vein thrombosis in cirrhosis and hepatocellular carcinoma.

RESULTS

Portal vein thrombosis occurs because of local inflammatory conditions in the abdomen and prothrombotic factors. Acute portal vein thrombosis is usually symptomatic when associated with cirrhosis and/or superior mesenteric vein thrombosis. Anticoagulation should be given for 3-6 months if detected early. If prothrombotic factors are identified, anticoagulation should be given lifelong. Chronic portal vein thrombosis usually presents with well tolerated upper gastrointestinal bleed. It is diagnosed by imaging, which demonstrates a portal cavernoma in place of a portal vein. Anticoagulation does not have a definite role, but bleeds can be treated with endotherapy or shunt surgery. Rarely liver transplantation may be considered.

CONCLUSION

Role of anticoagulation in chronic portal vein thrombosis needs to be further studied.