Detection Of Portal Vein Thrombosis Research Articles

Dual-Energy CT for the Detection of Portal Vein Thrombosis: Improved Diagnostic Performance Using Virtual Monoenergetic Reconstructions.

Purpose: To investigate the diagnostic performance of noise-optimized virtual monoenergetic images (VMI+) in dual-energy CT (DECT) of portal vein thrombosis (PVT) compared to standard reconstructions. Method: This retrospective, single-center study included 107 patients (68 men; mean age, 60.1 ± 10.7 years) with malignant or cirrhotic liver disease and suspected PVT who had undergone contrast-enhanced portal-phase DECT of the abdomen. Linearly blended (M_0.6) and virtual monoenergetic images were calculated using both standard VMI and noise-optimized VMI+ algorithms in 20 keV increments from 40 to 100 keV. Quantitative measurements were performed in the portal vein for objective contrast-to-noise ratio (CNR) calculation. The image series showing the greatest CNR were further assessed for subjective image quality and diagnostic accuracy of PVT detection by two blinded radiologists. Results: PVT was present in 38 subjects. VMI+ reconstructions at 40 keV revealed the best objective image quality (CNR, 9.6 ± 4.3) compared to all other image reconstructions (p < 0.01). In the standard VMI series, CNR peaked at 60 keV (CNR, 4.7 ± 2.1). Qualitative image parameters showed the highest image quality rating scores for the 60 keV VMI+ series (median, 4) (p ≤ 0.03). The greatest diagnostic accuracy for the diagnosis of PVT was found for the 40 keV VMI+ series (sensitivity, 96%; specificity, 96%) compared to M_0.6 images (sensitivity, 87%; specificity, 92%), 60 keV VMI (sensitivity, 87%; specificity, 97%), and 60 keV VMI+ reconstructions (sensitivity, 92%; specificity, 97%) (p ≤ 0.01). Conclusions: Low-keV VMI+ reconstructions resulted in significantly improved diagnostic performance for the detection of PVT compared to other DECT reconstruction algorithms.

Prevalence of portal vein thrombosis detected by computed tomography angiography in dogs.

To evaluate dogs with computed tomography angiography of the abdomen for overall prevalence of portal vein thrombosis and prevalence of portal vein thrombosis based on different disease categories. To evaluate dogs with and without portal vein thrombosis for differences in outcome. To compare ultrasound to computed tomographic angiography for identification of portal vein thrombosis. Abdominal computed tomography angiography of 223 client-owned animals was reviewed for evidence of portal vein thrombosis. Based on medical records, dogs were assigned to disease categories: (1) liver disease; (2) non-hepatic neoplasia; (3) pancreatitis; (4) infectious disease; (5) immune-mediated disease; (6) other; (7) multiple diseases. Different categories were compared for the prevalence of portal vein thrombosis. Outcome was evaluated in dogs with and without portal vein thrombosis. Ultrasound reports were reviewed to determine the detection of thrombosis on ultrasound. Twenty-eight dogs (13%) had portal vein thrombosis. The pancreatitis category contained the highest percentage of portal vein thrombosis among different categories (eight of 19; 42%). There was a similar outcome between dogs with and without portal vein thrombosis. Of 21 dogs with portal vein thrombosis that had ultrasound performed, ultrasound detected thrombosis in four of 21 (19%) cases. In this study, portal vein thrombosis prevalence was higher in dogs with pancreatitis compared to dogs with liver disease, non-hepatic neoplasia and other abdominal or systemic disease. The portal system should be carefully evaluated with imaging in dogs with pancreatitis. As compared to ultrasound, CT angiography is the imaging method of choice for detection of portal vein thrombosis in dogs.

Imaging and minimally invasive endovascular therapy in the management of portal vein thrombosis

Thrombosis of the portal venous system, although rare in the general population, is commonly diagnosed in patients with specific underlying conditions including prothrombotic diseases, cirrhosis, hepatobiliary malignancy, and intraabdominal inflammation. Recent improvements in imaging have played a fundamental role in increased detection of portal vein thrombosis (PVT), frequently reported in asymptomatic patients as an incidental finding. Minimally invasive, endovascular therapy is a medically rational option to achieve recanalization of the portal vein as an adjunct to conservative medical management. This review focuses on the advances in imaging modalities to diagnose, stage and follow-up PVT, and gives a short overview of the available endovascular techniques in this field.

Role of low-molecular-weight heparins in prevention of thromboembolic complication after transarterial chemoembolization in hepatocellular carcinoma.

Portal vein thrombosis (PVT) is a common complication after transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC). This is the first clinical study to evaluate the role of low-molecular-weight heparins (LMWHs) with TACE in HCC for the prevention of thromboembolism complications (PVT). This study was carried out on 40 patients with HCC requiring TACE who presented to the Tropical Medicine Department, Tanta University and Interventional Radiology Department of Ain-Shams University Hospitals starting from April 2015. Patients were divided in two groups: group I included 20 patients with HCC treated by TACE only. Group II included 20 patients with HCC treated by TACE and an adjuvant dose of LMWH. Radiological assessment of efficacy of procedure and detection of PVT as a complication was performed using ultrasound abdomen and pelvis and triphasic spiral computed tomography with contrast. This study was carried out on 40 patients with HCC requiring TACE who presented to the Tropical Medicine Department of Tanta University and Interventional Radiology Department of Ain-Shams University Hospitals. The incidence of PVT after TACE was higher in group I than group II, with seven cases in group I and only one case in group II. LMWH with TACE in HCC is strongly recommended for prevention of thromboembolism complications (PVT). However, larger randomized-controlled studies are needed to confirm these obvious findings.

Portal Vein Thrombosis in Patients with Hepatocellular Carcinoma: Diagnostic Accuracy of Gadoxetic Acid-enhanced MR Imaging.

Purpose To assess the diagnostic performance of gadoxetic acid-enhanced magnetic resonance (MR) imaging in the evaluation of portal vein thrombosis (PVT) in patients with hepatocellular carcinoma (HCC). Materials and Methods This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. A total of 366 patients with HCC who underwent gadoxetic acid-enhanced MR imaging between January 2007 and May 2013, including 134 with malignant PVT, 49 with benign PVT, and 183 without PVT matched for age and sex, comprised our study population. PVTs were complete in 125 patients and partial in 58 and were located in a major portal vein (n = 159) or segmental portal vein (n = 24). Two radiologists independently reviewed the MR images and assessed the sensitivity, specificity, and accuracy in the detection and characterization of PVT according to location (major vs segmental) and type (complete vs partial). The Fisher exact or χ(2) test was used to evaluate sensitivity difference between the subsets. Results Gadoxetic acid-enhanced MR imaging showed good sensitivity (reviewer 1, 84% [154 of 183 patients]; reviewer 2, 70% [129 of 183 patients]) and high specificity (reviewer 1, 89% [163 of 183 patients]; reviewer 2, 96% [176 of 183 patients]) in the detection of PVT. Diagnostic accuracy for differentiating malignant PVT from benign PVT was high (reviewer 1, 92% [141 of 154 patients]; reviewer 2, 95% [122 of 129 patients]). However, there was slightly lower sensitivity for detecting segmental PVT compared with that of major PVT in the malignant PVT group (reviewer 1, 95% [104 of 110 patients] vs 88% [21 of 24 patients]; reviewer 2, 82% [90 of 110 patients] vs 79% [19 of 24 patients]; P = .203 and .775 for reviewers 1 and 2, respectively). Conclusion Gadoxetic acid-enhanced MR imaging provided good diagnostic performance in the detection of PVT and the differentiation of malignant from benign PVT in patients with HCC. However, caution is needed when evaluating potential candidates for curative treatment because of the low sensitivity for segmental PVT in the malignant PVT group. (©) RSNA, 2016 Online supplemental material is available for this article.

Portal Vein Thrombosis after Partial Splenic Embolization in Liver Cirrhosis: Efficacy of Anticoagulation and Long-term Follow-up

To investigate the treatment and long-term outcome of portal vein thrombosis (PVT) after partial splenic embolization (PSE). From January 2006 to December 2011, 145 patients with hypersplenism caused by cirrhotic portal hypertension underwent PSE. In 11 cases, PVT was detected 13-42 days after PSE. Among the 11 patients, 5 underwent anticoagulant therapy because of clinical symptoms, and 6 did not receive anticoagulation because they were symptom-free (4 patients) or experienced variceal bleeding (2 patients). The long-term follow-up data from these 11 patients were analyzed retrospectively. The 11 patients with PVT had a mean splenic infarction ratio of 71.5%. The mean duration of follow-up was 37.6 months. During the follow-up period, none of the 5 patients who underwent anticoagulation developed variceal hemorrhage despite presenting with large esophagogastric varices. Four of the five patients achieved complete resolution of thrombosis, and one did not develop thrombus progression. However, among the 6 patients who did not undergo anticoagulation, 2 developed esophagogastric variceal hemorrhage secondary to thrombus progression, 3 developed cavernous transformation of the portal vein and variceal progression, and 1 had partial calcification of the thrombus. Two patients who had variceal bleeding or rebleeding underwent a transjugular intrahepatic portosystemic shunt. Complete recanalization of the portal vein was achieved after the procedures. PVT is a severe, potentially fatal complication of PSE. Early detection of PVT and prompt anticoagulation are effective to avoid serious consequences of PVT.

Risk factors and clinical characteristics of portal vein thrombosis after splenectomy in patients with liver cirrhosis

Portal vein thrombosis (PVT) is a potential lethal complication and may have negative influence on the prognosis after splenectomy in patients with liver cirrhosis. Prevention and timely detection of PVT are quite significant. There is a lack of knowledge about the clinical features and risk factors of PVT. Our study aimed to investigate the risk factors and clinical characteristics of PVT in order to figure out the high-risk individuals. We collected the clinical data of 472 consecutive patients with non-neoplastic liver cirrhosis who had undergone splenectomy from January 2008 to December 2010 in our institution. Clinical and surgical characteristics of patients who developed PVT postoperatively and those who did not develop PVT were compared. Univariate and multivariate analyses of risk factors of PVT were performed. The mortality and rebleeding rate of the patients were also evaluated. Of the 472 patients, 52 were excluded from the study. PVT developed in 71 (71/420, 16.9%) patients. Multivariate analysis revealed that wider preoperative portal vein diameter, postoperative thrombocytosis, prolonged prothrombin time and periesophagogastric devascularization were significantly correlated with PVT development [odds ratio (OR): 5.701, 2.807, 1.850 and 2.090, respectively]. The incidence of PVT in patients who took antiplatelet drugs was not lower than that in those who did not. Follow-up showed that patients in the PVT group had a tendency towards reduced overall survival but it was not statistically significant. Gastrointestinal bleeding occurred more often in the PVT group than that in the non-PVT group (P=0.044). Wider preoperative portal vein diameter, postoperative thrombocytosis, prolonged prothrombin time and periesophagogastric devascularization are independent risk factors of PVT. PVT is related with higher risk of postoperative gastrointestinal hemorrhage but has no significant impact on the overall survival.

Magnetic resonance portal venography: use of fast-acquisition true FISP imaging in the detection of portal vein thrombosis

To determine the accuracy of true fast imaging with steady-state precession (true FISP) in the diagnosis of portal vein thrombosis in patients with cirrhosis and compare it to contrast-enhanced three-dimensional (3D) magnetic resonance (MR) angiography, the reference standard. Twenty-four consecutive patients with suspected portal venous thrombosis underwent contrast-enhanced 3D MR angiography and true FISP imaging of the portal vein. All patients had undergone at least one other imaging study, either computed tomography, (CT) or ultrasound. Both sets of MR images were evaluated for patency of the portal venous system and for image quality. Portal vein thrombosis was diagnosed in six of the 24 patients. Four patients with portal vein thrombosis were accurately diagnosed on the true FISP sequence. This sequence also accurately diagnosed the patency of the portal vein in 17 patients. However, the results were inconclusive in three patients. The image quality of the true FISP sequence of the three inconclusive patients was graded as either poor or fair. Of these three patients, contrast-enhanced 3D MR angiography confirmed portal vein thrombosis in two patients and portal vein stenosis in one patient. True FISP imaging had a sensitivity of 67% and a specificity of 100% for the diagnosis of portal vein thrombosis. The results of the present study show that the true FISP sequence is useful in diagnosing portal vein thrombosis. It could be employed as an adjunct to contrast-enhanced MR angiography in the severely debilitated patient where respiratory motion may degrade the images or in patients where the use of intravenous contrast medium is not possible due to poor venous access.

Accuracy of magnetic resonance imaging for preoperative detection of portal vein thrombosis in liver transplant candidates

The detection of main portal vein thrombosis (PVT) on preoperative imaging of liver transplant candidates has important technical implications for the transplantation procedure. Data are scarce regarding the accuracy of magnetic resonance imaging (MRI) at detecting PVT. The aim of our study was to compare preoperative findings of the portal vein on MRI to operative findings at liver transplantation. Abdominal MRI and clinical records of 172 consecutive patients who received liver transplants between January 1999 and September 2004 were reviewed. Two radiologists independently evaluated the last abdominal magnetic resonance examinations obtained before liver transplantation, blinded to the original reading, operative findings, and clinical data. Findings on MRI were compared with intraoperative findings at transplantation. Main PVT was detected in 12 patients, in whom 8 were found to have thrombus at surgery, with 6 requiring a jump graft or thrombectomy. Sensitivity and specificity of MRI for detecting main PVT were 100% and 98%, respectively. The cause of discordance between findings on MRI and at transplantation in 2 cases was a diminutive caliber of the main portal vein that was interpreted as recanalized chronic thrombosis on MRI. In conclusion, in our study group MRI detected PVT in all liver transplant recipients requiring jump grafts at transplantation. The major reason for a false-positive MRI was a diminutive but patent portal vein.

Portal vein thrombosis: etiology, diagnostic strategy, therapy and management

Myeloproliferative disorder, liver cirrhosis with portal hypertension, deficiency of natural anticoagulant proteins, gene mutation and hepatocellular carcinoma are the most frequent causes of portal vein thrombosis (PVT). Higher accuracy of the diagnostic methods is the reason why today the cause of PVT can be found more frequently. With imaging methods, PVT with or without cavernous transformation can be diagnosed. Fresh thrombus can be undetected in sonography due to the low echogenity but can be recognized in color Doppler sonography, especially with contrast-enhancing agent. Contrast-enhanced 3D MR angiography allows a comparable accuracy in the detection of PVT as digital subtraction angiography. Therapeutical options of PVT consist of mechanical recanalization of the portal vein, local fibrinolysis with or without placement of transjugular intrahepatic portosystemic stent shunt (TIPS), combination of mechanical recanalization and local fibrinolysis, systemic thrombolytic therapy, anticoagulation alone and surgical thrombectomy. Once PVT is found in sonography, Doppler sonography may be performed in order to distinguish benign from malignant thrombus. If further information is needed, MR angiography or contrast enhanced CT is the next step. If these tests are unsatisfactory, digital subtraction angiography should be performed. Until the early nineties, shunt surgery was recommended in patients with PVT who bled despite endoscopic treatment. Today, in symptomatic noncavernomatous PVT, recanalization with local methods is recommended. Additional implantation of TIPS should be performed when the patient is cirrhotic. In recent PVT in non-cirrhotic patients anticoagulation alone is recommended. It is expected that in old PVT anticoagulation can prevent further extension of the thrombus.

Indwelling mesenteric venous catheterization for early detection of portal vein thrombosis: Possible application to pediatric liver transplantation

Portal vein thrombosis (PVT) is a well-recognized complication after liver transplantation, particularly in children. When it occurs early in the postoperative period, it has serious consequences, and rapid detection is essential. The purposes of this study were (1) to ascertain whether continuous monitoring of mesenteric venous pressure (MVP), via an indwelling mesenteric venous catheter, could assist in early detection of PVT and (2) to investigate the role of portography, via the catheter, in confirming this complication. An animal model of PVT was developed in pigs. At laparotomy, a heparin-coated catheter was inserted into a jejunal mesenteric vein, delivered percutaneously and connected to a pressure transducer. Conditions of PVT were simulated by progressive occlusion of the portal vein (PV) using a silastic tourniquet, and the degree of PV stenosis was assessed by Doppler ultrasound flow-velocity measurement. MVP was recorded 1 and 3 minutes after PV occlusion, and portography was performed via the indwelling catheter. There were significant increases in MVPs with all degrees of PV stenosis ( P < .01, Student's t test). No significant changes in MVP were noted between 1 and 3 minutes postocclusion. Portography clearly demonstrated PV stenosis. There were no instances of PVT, despite repeated and prolonged occlusion of the PV. Progressive degrees of PV stenosis have been clearly detected by an indwelling mesenteric venous catheter in an animal model. This method may be useful for the diagnosis and treatment of PVT after pediatric liver transplantation.

Sonographic features of portal vein thrombosis.

The ability of real-time sonography to demonstrate the liver venous network is well documented. Sonographic features of 21 cases of unsuspected portal vein thrombosis, detected by a screening sonography of the upper abdomen and subsequently confirmed by computed tomography, angiography, or surgery, are discussed. Sonographic features of portal vein thrombosis were an echogenic thrombus within the lumen of the vein (67%), demonstration of portal vein collateral circulation (48%), enlargement of the thrombosed segment of the vein (38%), and the so-called cavernomatous transformation of the portal vein (19%). Echogenic endoluminal thrombi were observed with the same incidences in malignant and benign disease. Sonography, unlike angiography, was unable to characterize neoplastic thrombi; only the combination of an echogenic thrombus and an adjacent hepatic mass was strongly suggestive of malignancy, especially hepatoma. The extensive use of sonography as a screening test in upper abdomen pathology will probably improve the detection of portal vein thrombosis, a diagnosis until now considered rare.