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Portal vein thrombosis in liver cirrhosis – the added value of contrast enhanced ultrasonography.

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Review

DOI: 10.11152/mu.2013.2066.182.pvt

Abstract

Portal vein thrombosis (PVT) is a frequent complication of liver cirrhosis and its prevalence increases with the severity of liver disease. Patients with liver cirrhosis and hepatocellular carcinoma may have either malignant or blunt (benign) PVT. In these patients, the diagnosis and characterization of PVT is important for the prognosis and further treatment.

Ultrasound (US) is the modality of choice for the diagnosis of PVT. The features of PVT on B-mode (gray-scale) US include: dilatation of the portal vein, visualization of the thrombus and, in chronic PVT- cavernous transformation. Sensitiv- ity of US in the diagnosis of PVT is improved by the use of Doppler US and of ultrasound contrast agents. In the latter years, contrast enhanced ultrasound (CEUS) showed high sensitivity in the differential diagnosis between benign and malignant PVT and could be the diagnostic method of choice for the characterization of PVT. Blunt thrombi are avascular and will not enhance during CEUS examination, while a hyperenhancement pattern of the portal thrombus in the arterial phase, with “wash out” in the portal or late phase is typical for malignant PVT.

Keywords: Portal vein thrombosis (PVT), Liver cirrhosis; Ultrasound (US), Contrast enhanced ultrasound (CEUS)

Portal vein thrombosis in liver cirrhosis – the added value of contrast enhanced ultrasonography.

Mirela Danilă, Ioan Sporea, Alina Popescu, Roxana Șirli

Department of Gastroenterology and Hepatology, “Victor Babeş” University of Medicine and Pharmacy, Timişoara, Romania

Received 12.03.2016 Accepted 30.03.2016 Med Ultrason

2016, Vol. 18, No 2, 218-223

Corresponding author: Dr. Mirela Danilă

73, Martir Petru Domășneanu str, ap.9 300351 Timişoara, Romania

Phone: + 40-723-480752, Fax: + 40-256-488003 E-mail: [email protected]

Introduction

Ultrasound (US) is the most used imaging method in the evaluation and surveillance of patients with hepatopathies, especially in patients with advanced fibrosis and cirrhosis.

According to all guidelines (AASLD, EASL-EORT) [1,2]

US is the only imaging method used for screening of hepa- tocellular carcinoma and is recommended to be performed every 6 months. PVT can be an incidental finding on ultra- sound surveillance especially when asymptomatic. Also, all patients with chronic liver diseases should undergo a US Doppler examination at the time of first diagnosis to assess the presence of signs of cirrhosis and portal hyper- tension as recommended by EFSUMB guidelines [3].

Liver cirrhosis – the end stage of liver disease – is a condition with many complications [4-6]. One that is

common is PVT that can lead to hepatic decompensation by increasing portal hypertension.

The prevalence of PVT increases with the severity of cir- rhosis, from 1% [7] in patients with compensated cirrhosis to 8-25% [8] in candidates for liver transplantation. Many fac- tors are involved: local (liver architectural changes, slowing of portal vein flow due to resistance increase in the cirrhotic liver, the presence of periportal lymphangitis) [9], systemic (unbalanced hemostasis with a tendency to hypercoagulabil- ity), and other congenital and acquired factors [10].

On the other hand, PVT is more frequent in patients with cirrhosis and hepatocellular carcinoma (HCC), oc- curring in approximately 35% of cases [11]. Malignant PVT in patients with HCC is a contraindication for cura- tive treatment and also for liver transplantation, due to the high rate of tumor recurrence [12]. However, differ- entiating between benign and malignant thrombi in portal veins is sometimes difficult. The use of contrast agents in ultrasound examination (CEUS) has been shown to in- crease the sensitivity of ultrasound for the detection and also for the characterization of portal thrombi.

The clinical consequences of PVT are related to thrombus extension. PVT can be classified anatomically

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Fig 1. a) Complete PVT (double arrow) in a patient with a large hepatocellular carcinoma (between arrows) situated in the proximity of the main portal vein; b) Recanalisation in benign portal vein thrombosis with cavernous transformation. Doppler US reveals the presence of color signals inside the thrombus.

Fig 2. a) Partial PVT in a patient with HCV decompensated liver cirrhosis with large perihepatic ascites;b) Doppler US ex- amination reveals color signals between the thrombus and por- tal vein wall suggesting partial PVT.

into four grades [13] according to where the thrombus extends: Grade 1: Partial PVT – the obstruction of the portal vein by the thrombus in less than 50% of its lumen;

Grade 2: obstruction of PV is greater than 50% or com- plete occlusion with or without minimal extension into the superior mesenteric vein (SMV); Grade 3: Complete thrombosis of both PV, thrombus extends to the proxi- mal part of the SMV; Grade 4: complete thrombosis – the portal vein thrombus affects proximal and also distal SMV.

Patients with limited PVT can be asymptomatic, but the most common clinical presentations in PVT patients are: gastrointestinal bleeding, abdominal pain, jaundice, and hepatic encephalopathy. If the thrombus involves proximally the superior mesenteric vein, the risk of intes- tinal infarction is high [14].

Gray-scale (B-mode imaging) and Doppler US in the diagnosis of PVT

In most patients, gray-scale and Doppler US allow the non-invasive diagnosis of PVT by demonstrating the presence of hyperechoic material within the portal vein, distension of the portal vein and its tributaries, and total or partial absence of flow [15].

In PVT the thrombus is observed as an echogenic le- sion within the portal vein. The thrombus echogenicity can be hypo-, hyper- or isoechoic in standard US and its echogenity is not predictive for the nature of PVT (be- nign or malignant), but the presence of an adjacent liver mass to the PVT is highly predictive for malignant PVT [15] (fig 1a). Sometimes, a recently formed thrombus may be anechoic and thus can be missed by standard US examination [15]. The lack of variation in the portal vein diameter with respiration, coupled with a portal vein di- ameter greater than 13-15 mm, is also highly indicative of portal vein occlusion [16].

Another sonographic feature of portal vein occlusion is the development of collaterals with cavernous transfor- mation (fig 1b). Because this transformation takes a long time to develop, the presence of portal cavernoma can be a marker for blunt thrombus [17]. Patients with malig- nant thrombus and hepatocellular carcinoma usually do not live long enough to develop a cavernoma.

In many cases the gray-scale US cannot differentiate between benign and malignant thrombosis [15]. In malig- nant PVT, US detects an echodense material in the portal vein lumen that can be limited or extensive, involving the common portal vein, the portal bifurcation and portal branches, sometimes with invasion of portal vein walls which is characteristic for malignant PVT [18].

Sensitivity of US in detecting PVT increases with PVT grade (100% in complete PVT) [13], false negative diagnosis occurring only in incomplete PVT.

Doppler US has been accepted as the “gold standard”

in assessing the direction of flow in the portal venous system [19], but it is also highly accurate in detecting thrombosis that involves the trunk of the portal vein and its intrahepatic branches.

There are some aspects in Doppler US very sensi- tive for the differentiation between malignant and benign PVT. Color signals within the thrombus (due to tumoral neovascularity) and detection of pulsatile flow in a portal vein thrombus using power Doppler US are criteria for malignant PVT [20].

Detection of pulsatile flow within a portal thrombus in patients with hepatocellular carcinoma was first reported by Pozniak et al [21]. Tanaka et al demonstrated that the presence of pulsatile flow in a portal thrombus is specific for malignant thrombosis [20]. Using detection of pulsa- tile flow within the thrombus as a criteria for malignant PVT diagnosis, the sensitivity and specificity of color Doppler sonography were 92% and 100% respectively, with 95% accuracy in the study of Lencioli et al [22].

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The presence of pulsatile flow in the portal vein thrombus had 82.5% sensitivity and 100% specificity for the diagnosis of malignant PVT in the Ueno et al study [23]. In the same study, the overall accuracy in differenti- ating between benign and malignant portal vein thrombi by power Doppler US was 87%. But the sensitivity of Doppler US in the detection of malignant thrombi is highly dependent on the size of the thrombus [24], lower than 20% [25,26].

From the clinical point of view, it is very important to determine whether PVT is complete (occupying the entire lumen of portal vein) or partial. Color Doppler US examination can be used to differentiate between com- plete and partial PVT revealing complete or partial ab- sence of color signals within the portal lumen [27] (fig 2).

CEUS in the diagnosis of PVT

The differentiation of a malignant vs. benign PVT is of paramount importance in the management of patients with liver cirrhosis. CEUS appeared to be superior to US and Doppler US for both the detection and characteriza- tion of PVT.

One of the indications for the use of CEUS in the EF- SUMB guidelines [28] is the characterization of PTV in cirrhotic patients, which is crucial for a therapeutic deci- sion, and also for the prognosis. Patients with malignant invasion of major branches of the portal vein or hepatic veins have a poor prognosis (stage IV by the TNM clas- sification) and are not candidates for surgical resection or liver transplantation [18].

CEUS allows detailed visualization of the hepatic mi- crovasculature system (similar to computer tomography [CT] or magnetic resonance imaging [MRI]), of focal liver lesions and also of portal vein thrombosis. Blunt thrombi are avascular and will not enhance during CEUS examination. Malignant thrombi have the same enhance-

ment pattern as the tumor from which they originated, in- cluding rapid arterial phase hyperenhancement and slow or weak portal venous wash out (fig 3) [28].

In the study of Rossi et al four patterns of PVT en- hancement were described during CEUS [26]: Pattern 1 – typical for thrombi without internal vascularization (thrombus enhancement is absent in all three phases).

This is a benign thrombosis; Pattern 2 – diffuse thrombus enhancement visible only during the early arterial phase, reflecting the diffuse thrombus vascularization similar to that of the tumor tissue from which it originates; Patterns 3 (linear or punctate enhancement) and 4 (multilinear or multipunctate enhancement) can be observed during either the arterial or portal and late phases of CEUS and are in- dicative of thrombus vascularization. Patterns 2, 3 and 4 are present in malignant PVT and may be combined. In the same study, the sensitivity of B mode ultrasound, color Doppler US, and CEUS were compared. CEUS sensitivity was significantly higher than color Doppler for the detec- tion of thrombi with and without continuity with the tumor tissue (p<0.05); for occluding vs. no occluding thrombi (p<0.05); and also for the characterization of PVT [26].

Dynamic contrast-enhanced MRI and 4-phase multi- detector CT are the most effective imaging techniques in the diagnosis of HCC and in the stadialization of the disease [2]. Macrovascular invasion such as PVT in HCC is a contraindication for curative treatments. Helical CT was less sensitive than CEUS for the characterization of PVT (98 vs. 67.6%) in the Rossi et al study [29], but CT and MRI also provide information regarding the throm- bus extension, such as SMV involvement. Also CT and MRI offer a simultaneous diagnosis of PVT and its pos- sible underlying cause such as HCC.

In the latter years many studies have been completed in order to assess the value of CEUS in the diagnosis of PVT and all demonstrated its high value in the characteri- zation and also for the detection of PVT (Table I).

Fig 3. a) Malignant PVT with hyperenhancement of the thrombus in the arterial phase, 12 seconds after SonoVue injection (arrows);

b) CEUS examination reveals thrombus vascularization with early arterial enhancement (“linear pattern” described by Rossi [29]) – suggesting malignant portal vein thrombosis; c) Malignant PVT– washout is present in the portal phase of CEUS examination (1 minute after contrast injection) (double arrows).

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In the Sorrentino et al study 108 cirrhotic patients with HCC and PVT without direct contiguity between the thrombus and HCC were evaluated by means of CEUS and fine needle biopsy (FNB). They reported the same sensitivity, specificity, positive and negative predic- tive value for CEUS and fine needle biopsy (FNB) for the diagnosis of PVT. There were 6 false-negative patients on baseline CEUS, but they were also false-negative at FNB [31]. In these patients CEUS showed no homogene- ous arterial enhancement at baseline and also no malig- nant cells were found by FNB. After 6 months follow-up an extension of the thrombi was observed in all 6 cases, with a “mosaic pattern” of enhancement following con- trast bolus at CEUS, confirmed as malignant by a repeat- ed FNB. If this “mosaic pattern” is considered suggestive for malignant PVT than the sensitivity of CEUS for the characterization of PVT is 100%. A false-negative result at FNB can be possible if biopsy is taken from a segment of the thrombus that does not contain malignant cells.

Using CEUS guided PVT biopsy the sensitivity of the method was highly improved [31].

In the Ueno et al study [30], the hyperenhancement pattern was present in all malignant thrombi (100% of the cases). The references methods in this study were CT, angiography, CT+angiography, pathological proof, or follow-up.

In the Raza et al study [34] 50 patients were restro- spectively evaluated by two independent readers. The performance of CEUS in differentiating malignant from benign PVT, were similar for both readers.

Even if all published studies showed very good re- sults for the characterization of PVT by CEUS, it must be mentioned that only a small number of patients were included (between 50-108 patients).

In some cases, US examination reveals only PVT without definite evidence of a mass-forming lesion in the liver or a very inhomogeneous hepatic echo texture. Con- firmation of the malignant nature of PVT using CEUS examination strongly suggests the presence of HCC (un- apparent or occult HCC) [35].

CEUS has some advantages over other imaging methods in the diagnosis of PVT: it is a fast and real-time examination that can be performed in the same session with thrombus detection and it is an inexpensive method with almost no complications and no irradiation.

In conclusion in most patients, B mode (standard) and Doppler US allows the non-invasive diagnosis of PVT, by demonstrating hyperechoic material within the portal vein, distension of the portal vein and its tributar- ies, and total or partial absence of flow.

CEUS proved to be a very sensitive method for char- acterization and also for the detection of PVT. The high sensitivity of this method recommends CEUS as the first line imaging method for the characterization of PVT and should be considered as the “gold standard method”. In some cases CEUS is the only imaging method available for the differential diagnosis between benign and malig- nant PVT (patients with contraindication for CT and/or MRI).

But we must bear in mind that US is an operator- dependent method, influenced by the examiner’s experi- ence, by the patient’s condition, and also by the US ma- chine performance.

Conflict of interest: none

Acknowledgements: The research published in this paper was made with support from a grant awarded by Table I. Clinical studies of CEUS efficacy in the characterization of portal vein thrombosis.

Study N Criteria for diagnosis Se

(%) Sp (%) Ac

(%) PPV (%) NPV

(%) Tarantino et al. Abdom Imag-

ing 2006 [26] 54 Enhancement features of PVT on CEUS /follow-up 88 - - - -

Ueno et al.

J Ultrasound Med 2006 [30] 55 Enhancement of PVT in malignant thrombosis/no

enhancement in benign PVT 100 100 100 100 100

Rossi et al.

Eur Radiol 2008 [29] 50 Enhancing tissue within the vessel lumen in the early

arterial phase in malignanat PVT/Spiral TC 98 - - - -

Sorrentino et al. World J Gas-

troenterol 2009 [31] 108 Enhancement features of PVT on CEUS/FNB 89.6 100 - 100 89.2 Song ZZ et al. Eur J Radiol

2010 [32] 17 Enhancement of PVT on CEUS /follow-up 100 66.7 93.3 - -

Danila et al. Med Ultrason

2011 [33] 38 Enhancement features of PVT (EFSUMB criteria) 97.2 - - - -

Raza SA et al. Abdom Imaging

2014 [34] 50 Enhancement of PVT on CEUS/ clinico-radiologic

follow-up 100

100 83

92 95

97 100

100 N – number of patients, Se – Sensitivity, Sp – specificity, Ac – accuracy, PPV – positive predictive value, NPV – negative predictive value

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the “Victor Babeş” University of Medicine and Pharma- cy Timisoara, in Programul III – C2 – PCFI – 2015/2016.

References

1. Bruix J, Sherman M; Practice Guidelines Committee, American Association for the Study of Liver Diseases.

Management of hepatocellular carcinoma. Hepatology 2005; 42: 1208-1236.

2. European Association for the Study of the Liver, Euro- pean Organisation for Research and Treatment of Cancer.

EASL–EORTC Clinical Practice Guidelines: Management of hepatocellular carcinoma. J Hepatol 2012; 56: 908–943.

3. Berzigotti A, Piscaglia F; EFSUMB Education and Profes- sional Standards Committee. Ultrasound in portal hyper- tension – part 2 – and EFSUMB recommendations for the performance and reporting of ultrasound examinations in portal hypertension. Ultraschall in Med 2012; 33: 8-32.

4. Pincus KJ, Tata AL, Watson K. Risk of venous thromboem- bolism in patients with chronic liver disease and the utility of venous thromboembolism prophylaxis. Ann Pharmaco- ther 2012; 46: 873-878.

5. Primignani M. Portal vein thrombosis, revisited. Dig Liver Dis 2010; 42: 163–170.

6. Søgaard KK, Horváth-Puhó E, Grønbaek H, Jepsen P, Vil- strup H, Sørensen HT. Risk of venous thromboembolism in patients with liver disease: a nationwide population-based case-control study. Am J Gastroenterol 2009; 104: 96-101.

7. Okuda K, Ohnishi K, Kimura K, et al. Incidence of portal vein thrombosis in liver cirrhosis. An angiographic study in 708 patients. Gastroenterology 1985; 89: 279–286.

8. Francoz C, Belghiti J, Vilgrain V, et al. Splanchnic vein thrombosis in candidates for liver transplantation: usefulness of screening and anticoagulation. Gut 2005; 54: 691–697.

9. Witte CL, Brewer ML, Witte MH, Pond GB. Protean mani- festations of pylethrombosis. A review of thirty-four pa- tients. Ann Surg 1985; 202: 191–202.

10. Amitrano L, Guardascione MA, Ames PR. Coagulation ab- normalities in cirrhotic patients with portal vein thrombo- sis. Clin Lab 2007; 53: 583-589.

11. Pirisi M, Avellini C, Fabris C, et al. Portal vein thrombo- sis in hepatocellular carcinoma: age and sex distribution in an autopsy study. J Cancer Res Clin Oncol. 1998; 124:

397–400.

12. Mazzaferro V, Regalia E, Doci R, et al. Liver transplanta- tion for the treatment of small hepatocellular carcinomas in patients with cirrhosis. N Engl J Med 1996; 334: 693-699.

13. Yerdel MA, Gunson B, Mirza D, et al. Portal vein throm- bosis in adults undergoing liver transplantation: risk fac- tors, screening, management, and outcome. Transplantation 2000; 69: 1873–1881.

14. DeLeve LD, Valla DC, Garcia-Tsao G; American Associa- tion for the Study Liver Diseases. Vascular disorders of the liver. Hepatology 2009; 49: 1729–1764.

15. Van Gansbeke D, Avni EF, Delcour C, Engelholm L, Struyven J. Sonographic features of portal vein thrombosis.

AJR Am J Roentgenol 1985; 144: 749–752.

16. Bolondi L, Gandolfi L, Arienti V, et al. Ultrasonography in the diagnosis of portal hypertension: diminished response of portal vessels to respiration. Radiology 1982; 142: 167- 172.

17. McNaughton DA, Abu-Yousef MM. Doppler US of the liver made simple. Radiographics 2011; 31: 161–188.

18. Piscaglia F, Gianstefani A, Ravaioli M, et al; Bologna Liver Transplant Group. Criteria for diagnosing benign portal vein thrombosis in the assessment of patients with cirrho- sis and hepatocellular carcinoma for liver transplantation.

Liver Transpl 2010; 16: 658-667.

19. Berzigotti A, Abraldes JG, Tandon P, et al. Ultrasonograph- ic evaluation of liver surface and transient elastography in clinically doubtful cirrhosis. J Hepatol 2010; 52: 846–853.

20. Tanaka K, Numata K, Okazaki H, Nakamura S, Inoue S, Takamura Y. Diagnosis of portal vein thrombosis in patients with hepatocellular carcinoma: efficacy of color Doppler sonography compared with angiography. AJR Am J Roent- genol 1993; 160: 1279-1283.

21. Pozniak MA, Baus KM. Hepatofugal arterial signal in the main portal vein: an indicator of intravascular tumor spread. Radiology 1991; 180: 663-666.

22. Lencioni R, Caramella D, Sanguinetti F, Battolla L, Falaschi F, Bartolozzi C. Portal vein thrombosis after percutaneous ethanol injection for hepatocellular carcinoma: value of color Doppler sonography in distinguishing chemical and tumor thrombi. AJR Am J Roentgenol 1995; 164: 1125-1130.

23. Ueno N, Tomiyama T, Tano S, Wada S, Miyata T. Color Doppler ultrasonography in the diagnosis of portal vein in- vasion in patients with pancreatic cancer. J Ultrasound Med 1997; 16: 825–830.

24. Tarantino L, Ambrosino P, Di Minno MN. Contrast-en- hanced ultrasound in differentiating malignant from benign portal vein thrombosis in hepatocellular carcinoma. World J Gastroenterol 2015; 21: 9457-9460.

25. Tarantino L, Francica G, Sordelli I, et al. Diagnosis of benign and malignant portal vein thrombosis in cirrhotic patients with hepatocellular carcinoma: color Doppler US, contrast-enhanced US, and fine-needle biopsy. Abdom Im- aging 2006; 31: 537–544.

26. Rossi S, Rosa L, Ravetta V, et al.Contrast-enhanced versus conventional and color Doppler sonography for the detec- tion of thrombosis of the portal and hepatic venous systems.

AJR Am J Roentgenol 2006; 186: 763-773.

27. Sabol TP, Molina M, Wu GY. Thrombotic venous diseases of the liver. J Clin Transl Hepatol 2015; 3: 189–194.

28. Claudon M, Dietrich CF, Choi BI, et al. Guidelines and good clinical practice recommendations for contrast en- hanced ultrasound (CEUS) in the liver – Update 2012: A WFUMB-EFSUMB initiative in cooperation with repre- sentatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS.

Ultrasound Med Biol 2013; 39: 187–210.

29. Rossi S, Ghittoni G, Ravetta V, et al. Contrast-enhanced ultrasonography and spiral computed tomography in the detection and characterization of portal vein thrombosis complicating hepatocellular carcinoma. Eur Radiol 2008;

18: 1749-1756.

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30. Ueno N, Kawamura H, Takahashi H, et al. Characterization of portal vein thrombus with the use of contrast-enhanced sonography. J Ultrasound Med 2006; 25: 1147–1152 31. Sorrentino P, D’Angelo S, Tarantino L, Ferbo U, Bracigli-

ano A, Vecchione R. Contrast-enhanced sonography ver- sus biopsy for the differential diagnosis of thrombosis in hepatocellular carcinoma patients. World J Gastroenterol 2009;15: 2245-2251.

32. Song ZZ, Huang M, Jiang TA, et al. Diagnosis of portal vein thrombosis discontinued with liver tumors in patients with liver cirrhosis and tumors by contrast-enhanced US: a pilot study. Eur J Radiol 2010; 75: 185-188.

33. Dănilă M, Sporea I, Popescu A, Şirli R, Şendroiu M. The value of contrast enhanced ultrasound in the evaluation of the nature of portal vein thrombosis Med Ultrason 2011;

13: 102-107.

34. Raza SA, Jang HJ, Kim TK. Differentiating malignant from benign thrombosis in hepatocellular carcinoma:

contrast-enhanced ultrasound. Abdom Imaging 2014; 39:

153–161.

35. Spârchez Z, Radu P, Zaharia T, et al. B-mode and Contrast Enhanced Ultrasound guided biopsy of portal vein throm- bosis. Value in the diagnosis of occult hepatocellular carci- noma in liver cirrhosis. Med Ultrason 2010; 12: 286-294.

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