Multimodality imaging of primary extrahepatic portal vein obstruction (EHPVO): what every radiologist should know

The Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management

PURPOSE

To illustrate diagnostic and interventional imaging for the characterization and treatment of portal vein thrombosis (PVT).

INTRODUCTION

The broad spectrum of congenital and acquired PVT manifestations is illustrated, with a focus on the pediatric population; diagnostic and interventional imaging techniques are described.

DESCRIPTION

PVT frequently presents as an incidental finding at imaging in the screening for liver diseases or for other unrelated reasons. PVT can be classified based on: extension (intrahepatic, extrahepatic, involving the spleno-mesenteric tract, etc.); degree (partial or complete); onset (acute or chronic); and with or without cavernomatous transformation. This comprehensive review relies on the experience gained from a large series of congenital and acquired PVT in a referral center for pediatric and adult liver transplantation. Diagnostic and interventional imaging techniques are described, including: color-Doppler and contrast-enhanced Ultrasound; CT and MR angiography; retrograde portography; percutaneous transhepatic, transplenic, and transmesenteric portography; transjugular intrahepatic portosystemic shunt creation. Pre- and post-operative imaging assessment of the surgical meso-rex bypass is discussed. The description is enriched with an original series of pictorial imaging findings.

CONCLUSION

PVT is a clinical condition associated with significant morbidity and mortality. Diagnostic and interventional imaging plays a crucial role in both conservative and operative management.

Benign Hepatic Nodules in Patients With Primary Extrahepatic Portal Vein Obstruction: Clinical and Magnetic Resonance Imaging Features

Background/objective

To retrospectively evaluate the magnetic resonance imaging (MRI) features of benign hepatic nodules in patients with extrahepatic portal vein obstruction (EHPVO) and assess predictable features for their development.

Methods

This retrospective observational study included 18 diagnosed patients of EHPVO who underwent contrast enhanced abdominal MRI at our Institute between June 2016 and May 2017, and who could be followed up for at least two years. The patients with liver nodules formed the study group (n = 8; 4 males, 4 females; mean age: 26.1 ± 10.9 years) and patients without liver nodules were controls (n = 10; 3 males, 7 females; mean age: 24.2 ± 15.1 years). Liver nodules were confirmed as benign by either biopsy or stability on follow up imaging. MRI features of liver nodules were assessed. Clinical details and imaging data of the study group were compared with controls to assess predictable features.

Results

There was no statistically significant difference in age, gender, clinical characteristics and upper gastrointestinal endoscopic findings between the study and control groups. The size of the lienorenal collateral, left renal vein and superior mesenteric vein were significantly larger in the study group (P < 0.05). In the study group, the majority had multiple hepatic nodules with most of them being isointense on T1 (18/35; 51.4%) and T2-weighted images (16/35; 45.7%) and showing restriction of diffusion (21/35; 60%). All (n = 35) lesions showed arterial phase hyperenhancement and none showed washout in the venous phase. The patients in the control group did not develop any liver nodules during the follow-up period.

Conclusion

Liver nodules in patients with EHPVO are likely to be benign and have characteristic MRI features. Significantly larger lienorenal collateral, left renal vein and superior mesenteric vein were associated with the development of these nodules.

Bleeding per rectum in pediatric population: A pictorial review

Bleeding per rectum in children can be seen in congenital as well as acquired conditions that may require medical or surgical management. The present review article is aimed to discuss the imaging findings of some common and uncommon causes of bleeding per rectum in children.

Bleeding per rectum in pediatric population: A pictorial review

Bleeding per rectum in children can be seen in congenital as well as acquired conditions that may require medical or surgical management. The present review article is aimed to discuss the imaging findings of some common and uncommon causes of bleeding per rectum in children.

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.

Histological analyses of trucut liver biopsies from patients with noncirrhotic portal fibrosis and extra-hepatic portal vein obstruction

Background

Both noncirrhotic portal fibrosis (NCPF) and extrahepatic portal venous obstruction (EHPVO) are important causes of noncirrhotic portal hypertension (PH) in the Asian region. In this study, we analyzed the histopathological changes of liver needle-core biopsies from patients with NCPF and EHPVO.

Patients and Methods

The patients were diagnosed as per the Asia Pacific Association for the Study of Liver (APASL) criteria. Minimum adequacy criteria for liver core biopsies were defined, and finally, 69 liver biopsies from patients with NCPF and 100 liver biopsies from patients with EHPVO were analyzed. All histological parameters were predefined, and three experienced pathologists analyzed the biopsies after reaching consensus. Institute ethics committee clearance was taken.

Results

Although some histological features were overlapping, phlebosclerosis of intra-hepatic branches of the portal vein (PV), periportal aberrant vascular channels, remnant portal tracts, and hepatic fibrosis beyond the portal tracts without the formation of complete hepatic nodules (P < 0.001 for all) were common histological characteristics of NCPF on core-needle liver biopsies; while maintained lobular architecture, nonspecific dilatation of PV branches, absence of intra-hepatic PV phlebosclerosis, aberrant vascular channels, and significant fibrosis were characteristics of EHPVO.

Conclusions

Despite the considerable histological overlap between NCPF and EHPVO, careful histological evaluation, supplemented by clinical features, radiological and biochemical findings can help in making a conclusive diagnosis. Patients with NCPF and EHPVO with clinical jaundice show transaminitis, high serum alkaline phosphatase level, more variceal bleed, and histological evidences of nodular regenerative hyperplasia.

Extrahepatic Portal Venous Obstruction With Hepatic Enzyme Elevation Resembling Hepatitis in Patients With Cancer

BACKGROUND/AIM

Chemotherapy is often halted due to abnormal liver function resembling hepatitis. But the cause can be extrahepatic portal venous obstruction (EHPVO) with hepatic enzyme elevation rather than being an adverse effect of chemotherapy. We investigated EHPVO with hepatic enzyme elevation in patients with cancer.

PATIENTS AND METHODS

Data of these hospitalized patients with solid tumors between January 2013 and September 2017 were collected. The criteria for study inclusion were: (i) Extrahepatic malignancy; (ii) computed tomographic scans showing a tumor with external compression of the extrahepatic portal vein; and (iii) serum aminotransferase (AST) or alanine transaminase (ALT) level three times above the normal value.

RESULTS

Thirteen out of 377 (3%) patients developed EHPVO with hepatic enzyme elevation, as demonstrated from computed tomographic scan. Four cases (31%) also had vascular thrombosis (three portal vein and one inferior vena cava). Serum AST increased from 34±11 to 169±94 U/l. ALT increased from 9±38 to 177±104 U/l. There was no relationship of EHPVO with viral markers and cirrhosis. Six cases received chemotherapy with liver function improvement.

CONCLUSION

EHPVO occurred in patients with metastatic cancer, leading to hepatic enzyme elevation resembling hepatitis without hepatitis risk factors and cirrhosis. Before withholding chemotherapy due to hepatic enzyme elevation, the possibility of EHPVO should firstly be excluded.

Changes in liver morphology in patients with extrahepatic portal venous obstruction: a retrospective magnetic resonance imaging study

OBJECTIVE

To investigate the liver parenchymal changes on MRI in patients with extrahepatic portal venous obstruction (EHPVO).

METHODS

This was a retrospective evaluation of the MRI studies in patients with EHPVO between January 2016 and April 2018. The diagnosis of EHPVO in each case had been established on the basis of clinical and Doppler parameters. Following findings were recorded on MRI: liver size; outline; overall volume redistribution; volume redistribution of caudate, right and left lobes; signal heterogeneity, intrahepatic biliary radicle dilatation, focal liver lesions, gallstones and ascites.

RESULTS

A total of 164 MRI studies were evaluated. Median age was 27 years (range, 6-70). There were 90 (54.9%) males and 74 (45.1%) females. The median liver size was 14 cm (range 5-17). The median spleen size was 15.9 cm (range, 6-28). A spleen size ≥12 cm was seen in 136 (82.9%) patients. The liver outline was nodular in 32 (19.5%) patients. Volume redistribution was seen in 63 (38.4%) patients. Caudate lobe hypertrophy was seen in 49 (29.9%) patients. Right lobe atrophy and hypertrophy was seen in 4 (2.4%) and 1 (0.6%) patients respectively. Left lobe atrophy and hypertrophy was seen in 15 (9.1%) and 10 (6.1%) patients respectively. 30 MRI (18.3%) showed heterogeneous signal intensity. Focal lesions were seen in 22 (13.4%) patients. Intrahepatic biliary radicle dilatation, gallstones and ascites were seen in 120 (73.2%), 54 (32.9%) and 26 (15.9%) patients respectively.

CONCLUSION

Liver morphological changes are common in EHPVO.

ADVANCES IN KNOWLEDGE

The morphological changes in liver in patients with EHPVO have not been described previously. This information will prevent misdiagnosis of this condition as cirrhosis.

Portal Cavernoma Cholangiopathy: Histologic Features and Differential Diagnosis

Objectives

Portal cavernoma cholangiopathy (formerly portal biliopathy) is a type of biliary injury that occurs in association with a portal vein thrombus or cavernoma. Although the radiographic features of portal cavernoma cholangiopathy have been enumerated in the literature, its histologic features have not been described in detail.

Methods

We describe the histologic findings in liver specimens from three patients with radiologically confirmed portal cavernoma cholangiopathy.

Results

Of the three patients, one underwent surgical resection due to a clinical suspicion for cholangiocarcinoma, one had a liver biopsy sample obtained for evaluation of possible cirrhosis, and one had a clinically suspicious "hilar mass" at the time of orthotopic liver transplant. Histologic features common among the three liver specimens included portal venous abnormalities, where the portal veins were obliterated or small relative to the portal tract size, and obstructive biliary changes, such as ductular reaction and reactive epithelial atypia accompanied by a mixed inflammatory cell infiltrate with neutrophils.

Conclusions

This case series provides clinicopathologic characteristics of portal cavernoma cholangiopathy. Histologic changes are reminiscent of hepatoportal sclerosis and/or bile duct obstruction. Attention to portal veins can provide helpful diagnostic clues, especially when biopsy samples are obtained from patients with a known portal vein thrombus or cavernoma.

Contrast-enhanced Computed Tomography Imaging of Splenic Artery Aneurysms and Pseudoaneurysms: A Single-center Experience

AIM

The aim of our study was to evaluate the computed tomography (CT) imaging features of splenic artery aneurysm and pseudoaneurysm and to identify the disease conditions related to the same. We also wanted to ascertain any relationship between these associated disease conditions and the imaging features of the aneurysms.

MATERIALS AND METHODS

This retrospective study included patients diagnosed to have splenic artery aneurysms on contrast-enhanced CT examination between January 2001 and January 2016. Data were obtained from the picture archiving and communication system. The size, number, location, morphology, the presence of thrombosis, calcification, and rupture of the aneurysms were evaluated.

RESULTS

A total of 45 patients were identified with a mean age of 45 years. Splenic artery aneurysms were idiopathic in 12 (26.6%) patients. In the remaining patients, the main associated disease conditions included pancreatitis 15 (33%), chronic liver disease with portal hypertension 8 (18%), and extrahepatic portal vein obstruction (EHPVO) 6 (13%). Statistically significant findings included the relationship between EHPVO and multiple aneurysms (P = 0.002), chronic liver disease and fusiform aneurysm (P = 0.008), and smaller size of idiopathic aneurysms (P < 0.001).

CONCLUSION

Based on this study, splenic artery aneurysms were associated with a variety of etiologies. The characteristics of the aneurysms such as size, location, and morphology vary with the associated disease conditions. These variations may have implications for the management.

Non-cirrhotic portal hypertension: an imaging review

Non-cirrhotic portal hypertension (NCPH) comprises a group of diseases that are characterized by increased portal pressure in the absence of cirrhosis of the liver. It may arise as a result of either primary hepatic disease or the effects of systemic disorders on liver. The natural course of NCPH is largely indolent and benign with an overall better outcome than cirrhosis, as long as the complications of portal hypertension are properly managed and regular surveillance is carried out. However, due to the numerous and variable etiological factors and lack of standardized diagnostic criteria, this entity is under-recognized clinically as well as pathologically and often gets mislabeled as cryptogenic cirrhosis. Therefore, it is imperative for radiologists to be aware of the imaging features of various entities that constitute NCPH to facilitate early recognition of this disorder. The present review shall comprehensively discuss the role of imaging in the diagnosis of obliterative portal venopathy, which is a common and one of the most poorly understood disorders leading to NCPH. The other radiologically relevant entities will also be briefly appraised.

Hepatic morphology abnormalities: beyond cirrhosis

The diagnosis of cirrhosis can be reached on the basis of established hepatic morphological changes. However, some other conditions can mimic cirrhosis. The aim of this pictorial essay is to review the CT and MRI appearances of hepatic morphology abnormalities in the cirrhotic liver and other diseases, describing pathologic conditions that can mimic cirrhosis, with useful tips for the differential diagnosis. Mimickers of cirrhosis include congenital hepatic fibrosis, Caroli disease, Budd-Chiari Syndrome, hepatoportal sclerosis, cavernous transformation of the portal vein, pseudocirrhosis from metastatic disease, acute liver failure, post-therapeutic morphologic changes in the liver, and infective conditions including schistosomiasis and oriental cholangiohepatitis. Recognizing the hepatic morphological changes in images can help radiologists to diagnose cirrhosis and other diseases in early stages.

Portal vein thrombosis after cesarean section in a patient on prolonged bed rest due to threatened preterm labor

Portal vein thrombosis is a rare but life-threatening complication during pregnancy and postpartum period. Color Doppler ultrasound is useful for prompt diagnosis. Although the risk of complications should be considered, successful pregnancy with comorbid portal vein thrombosis is possible with appropriate anticoagulation therapy and close monitoring.

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.

Portal cavernoma cholangiopathy: diagnosis, imaging, and intervention

The term portal cavernoma cholangiopathy refers to the biliary tract abnormalities that accompany extrahepatic portal vein obstruction (EHPVO) and subsequent cavernous transformation of the portal vein. EHPVO is a primary vascular disorder of the portal vein in children and adults manifested by longstanding thrombosis of the main portal vein. Nearly all patients with EHPVO have manifestations of portal cavernoma cholangiopathy, such as extrinsic indentation on the bile duct and mild bile duct narrowing, but the majority are asymptomatic. However, progressive portal cavernoma cholangiopathy may lead to severe complications, including secondary biliary cirrhosis. A spectrum of changes is seen radiologically in the setting of portal cavernoma cholangiopathy, including extrinsic indentation of the bile ducts, bile duct stricturing, bile duct wall thickening, angulation and displacement of the extrahepatic bile duct, cholelithiasis, choledocholithiasis, and hepatolithiasis. Radiologists must be aware of this disorder in order to provide appropriate imaging evaluation and interpretation, to facilitate appropriate treatment and to distinguish this entity from its potential radiologic mimics.

Imaging and radiological interventions in extra-hepatic portal vein obstruction

Extrahepatic portal vein obstruction (EHPVO) is a primary vascular condition characterized by chronic long standing blockage and cavernous transformation of portal vein with or without additional involvement of intrahepatic branches, splenic or superior mesenteric vein. Patients generally present in childhood with multiple episodes of variceal bleed and EHPVO is the predominant cause of paediatric portal hypertension (PHT) in developing countries. It is a pre-hepatic type of PHT in which liver functions and morphology are preserved till late. Characteristic imaging findings include multiple parabiliary venous collaterals which form to bypass the obstructed portal vein with resultant changes in biliary tree termed portal biliopathy or portal cavernoma cholangiopathy. Ultrasound with Doppler, computed tomography, magnetic resonance cholangiography and magnetic resonance portovenography are non-invasive techniques which can provide a comprehensive analysis of degree and extent of EHPVO, collaterals and bile duct abnormalities. These can also be used to assess in surgical planning as well screening for shunt patency in post-operative patients. The multitude of changes and complications seen in EHPVO can be addressed by various radiological interventional procedures. The myriad of symptoms arising secondary to vascular, biliary, visceral and neurocognitive changes in EHPVO can be managed by various radiological interventions like transjugular intra-hepatic portosystemic shunt, percutaneous transhepatic biliary drainage, partial splenic embolization, balloon occluded retrograde obliteration of portosystemic shunt (PSS) and revision of PSS.

Imaging Diagnosis of Splanchnic Venous Thrombosis

Splanchnic vein thrombosis (SVT) is a broad term that includes Budd-Chiari syndrome and occlusion of veins that constitute the portal venous system. Due to the common risk factors involved in the pathogenesis of these clinically distinct disorders, concurrent involvement of two different regions is quite common. In acute and subacute SVT, the symptoms may overlap with a variety of other abdominal emergencies while in chronic SVT, the extent of portal hypertension and its attendant complications determine the clinical course. As a result, clinical diagnosis is often difficult and is frequently reliant on imaging. Tremendous improvements in vascular imaging in recent years have ensured that this once rare entity is being increasingly detected. Treatment of acute SVT requires immediate anticoagulation. Transcatheter thrombolysis or transjugular intrahepatic portosystemic shunt is used in the event of clinical deterioration. In cases with peritonitis, immediate laparotomy and bowel resection may be required for irreversible bowel ischemia. In chronic SVT, the underlying cause should be identified and treated. The imaging manifestations of the clinical syndromes resulting from SVT are comprehensively discussed here along with a brief review of the relevant clinical features and therapeutic approach.