Septic thrombosis of the portal vein due to peripancreatic ligamental abscess

Septic thrombus formation of both the main portal vein and its intrahepatic branches were observed on CT in a patient with peripancreatic abscess. The septic thrombosis of portal vein (STPV) extended from the level of porta hepatis into the intrahepatic branches, but the portal vein and superior mesenteric vein at the level of pancreatic head were preserved with no evidence of thrombosis angiographically. The gas-containing abscess near the head of the pancreas extended toward the hepatic hilum and surrounded the portal vein and its branches on CT. It was concluded that these thrombi of portal vein branches at porta hepatis and intrahepatic branches were caused by extensions of peripancreatic abscess via the hepatoduodenal ligament and ligamentum teres. Computed tomography was useful in depicting the ligamentous spread of peripancreatic abscess resulting in STPV. Received: 29 September 1997; Revision received: 13 February 1998; Accepted: 16 February 1998     

Hemodynamics of portal blood flow shown by CT portography. Work in progress

Computed tomography and arterial portography were combined in 12 patients for studies of the anatomy and hemodynamics of the portal venous system. This technique was found to be more sensitive than conventional venous-phase angiograms of the superior mesenteric and splenic arteries for evaluation of the anatomy of the portal venous system and extent of thrombosis in patients with cavernous transformation and also facilitated recognition of subtle evidence of hepatofugal flow and portosystemic shunts. CT portography can be employed when conventional angiograms fail to show the portal vein adequately.     

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.     

Adenocarcinoma of the pancreatic ducts: comparative evaluation with CT and MR imaging at 1.5 T.

A prospective comparison of computed tomography (CT) and magnetic resonance (MR) imaging at 1.5 T was performed in 50 patients with the suspected diagnosis of pancreatic carcinoma. CT scans were obtained before and after administration of contrast material in 41 of 50 patients (82%); 34 of 41 postcontrast scans (83%) were obtained with dynamic CT. MR images were interpreted without knowledge of the results of CT, ultrasound, cholangiography, or endoscopic retrograde cholangiopancreatography in 48 patients (96%). Surgical correlation of findings at CT and MR imaging was performed in 24 patients (48%) at laparotomy and in two patients (4%) at autopsy. On T1-weighted MR images, relatively diminished signal intensity of tumor compared with that of the adjacent pancreas was a consistent finding. MR imaging proved superior to CT in identification of pancreatic carcinoma (particularly in smaller intrapancreatic tumors), peripancreatic extension, vascular and portal vein invasion, and duodenal invasion. These results suggest that MR imaging of the pancreas is superior in many instances to CT in preoperative evaluation of pancreatic carcinoma.     

Pseudothrombosis in the portal venous system: a potential pitfall with gadolinium-enhanced dynamic gradient-recalled echo imaging of the liver

Gadolinium-enhanced dynamic magnetic resonance (MR) images in 90 patients were reviewed to assess the artifacts mimicking portal venous thrombosis. The incidence of definite signal-intensity decrease mimicking pathologic condition was higher (P < 0.01) in the right (8%) and left (9%) portal vein branches and portal trunk (6%) than in the splenic (0%) or superior mesenteric (1%) vein with equilibrium-phase images. Radiologists should remember that dynamic MR images occasionally show signal-intensity decrease mimicking portal venous thrombosis due to flow artifact.     

The correlation between MR and angiography in portal hypertension

Forty-two MR examinations and hepatic panangiograms in 38 patients with portal hypertension were correlated with MR images to determine the ability of MR to detect portal vein hemodynamics. These studies were prospectively analyzed for degree of portal perfusion and direction of flow, portal vein thrombosis, and presence and type of shunt surgery. Thirty-three MR examinations were determined to have grade I (good) or II (fair) portal blood flow. Twenty-nine of these were grade I or II by angiography; the other four were grade IV. Of the eight cases documented as grade IV (hepatofugal portal blood flow) by angiography, none were considered grade IV by MR, suggesting that MR was unable to detect retrograde flow. The other case was not graded because of cavernous transformation of the portal vein. MR correlated well with angiography for the detection or absence of portal vein thrombus, agreeing with angiography in 41 of 42 cases. Two angiographically proven cases of portal vein thrombosis were correctly identified on MR. MR correctly identified the absence of portal vein clot in 39 of 40 angiographically negative cases. MR and angiography also agreed in 41 of 42 cases that a shunt was either present/absent or patent/occluded. The single error was due to inadequate MR scanning in the region of interest. The results show that MR cannot be used to grade blood flow in the portal vein. However, MR accurately detects portal vein thrombosis and the patency of surgical shunts.     

Pancreatic-phase versus portal vein-phase helical CT of the pancreas: optimal temporal window for evaluation of pancreatic adenocarcinoma

OBJECTIVE: Our objective was to use helical CT to compare the enhancement attenuation values of pancreatic adenocarcinoma, adjacent normal pancreas, and critical vascular structures during the pancreatic phase and portal vein phase. SUBJECTS AND METHODS: Forty-one patients with pathologically proven pancreatic adenocarcinoma underwent dual-phase thin-section dynamic helical CT using a pancreatic-phase and portal vein-phase protocol. The scan delay after initiation of the contrast bolus was 40 sec for the pancreatic phase and 70 sec for the portal vein phase. Attenuation values after i.v. contrast administration were calculated during both phases of scanning for normal pancreas, pancreatic tumor, celiac axis, superior mesenteric artery, superior mesenteric vein, splenic vein, and portal vein. Quantitative values were assessed using regions of interest. RESULTS: Mean differences of enhancement between tumor and normal pancreas were significantly greater in the pancreatic phase (57 H) than the portal vein phase (35 H) (p = .0001). Enhancement values of all the critical vascular structures were also significantly greater in the pancreatic phase than the portal vein phase (p < .001). CONCLUSION: With dynamic thin-section helical CT, pancreatic-phase scanning provides greater differences in contrast enhancement between normal pancreas and pancreatic tumor and between pancreatic tumors and surrounding critical vascular structures than does portal vein-phase scanning.     

肝硬化门静脉性胆病的影像表现

目的：探讨肝硬化门静脉高压性胆病（PB）的MSCT及MRI表现。方法：回顾性分析16例肝硬化PB患者的MSCT及MRI表现,分析门静脉血栓导致PB的解剖位置和临床表现。结果：16例患者中门静脉海绵样变13例,其中8例合并门静脉血栓;门静脉和／或门静脉分支血栓3例。16例患者中3例表现为肝内胆管扩张,9例表现为肝外胆管及一侧肝内胆管扩张,4例表现为肝外胆管和两侧肝内胆管扩张。本组病例门静脉系统侧支循环的类型包括食道一胃底静脉曲张13例（13／16,81％）、胰腺周围静脉曲张10例（10／16,63％）和胆囊静脉曲张10例（10／16,63%）。结论：肝硬化门静脉高压患者出现肝外或肝内胆管扩张时应考虑门静脉高压性胆病的可能。     

Detection of thrombosis in the portal venous system: comparison of contrast-enhanced MR angiography with intraarterial digital subtraction angiography

PURPOSE: To determine whether intraarterial digital subtraction angiography (DSA) can be replaced by contrast material-enhanced magnetic resonance (MR) angiography in the assessment of patency or thrombosis of the portal venous system in patients with portal hypertension. MATERIALS AND METHODS: Thirty-six patients with portal hypertension underwent contrast-enhanced MR angiography and intraarterial DSA for assessment of the portal venous system. The images were evaluated for vessel patency or thrombosis of the portal, splenic, or superior mesenteric vein. RESULTS: Of the 101 vessels evaluated, 42 were thrombosed. Overall sensitivity, specificity, and accuracy for the detection of thrombosis were 100%, 98%, and 99%, respectively, for MR angiography and 91%, 100%, and 96%, respectively, for DSA; differences between the imaging methods were not statistically significant. Only in four patients with six vessels (6%) were there discordant findings between MR angiography and DSA. CONCLUSION: Noninvasive contrast-enhanced MR angiography has the potential to replace intraarterial DSA as the standard method to assess the whole portal venous system.     

Applications of percutaneous mechanical thrombectomy in transjugular intrahepatic portosystemic shunt and portal vein thrombosis

Portal vein thrombosis (PVT) is an uncommon cause for presinusoidal portal hypertension. PVT can be caused by one of three broad mechanisms: (1) spontaneous thrombosis when thrombosis develops in the absence of mechanical obstruction, usually in the presence of inherited or acquired hypercoagulable states; (2) intrinsic mechanical obstruction because of vascular injury and scarring or invasion by an intrahepatic or adjacent tumor; or (3) extrinsic constriction by adjacent tumor, lymphadenopathy or inflammatory process. Usually, several combined factors are necessary to result in PVT. The consequences of portal vein thrombosis are mostly related to the extension of the clot within the vein. Gastrointestinal bleeding from gastroesophageal varices is the most frequent presentation. Noninvasive imaging techniques are currently used for the screening of patients and the initial diagnosis of PVT. The invasive techniques are reserved for cases when noninvasive techniques are inconclusive, before percutaneous interventional treatment, or in preoperative assessment of patients who are candidates for surgery. Recanalization of the portal vein with anticoagulation alone may not be consistent or appropriate in highly symptomatic patients. Catheterization of the superior mesenteric artery (SMA) is helpful for diagnosis as well as for therapy by allowing the intra-arterial infusion of thrombolytic drugs in the same setting. Direct transhepatic portography allows precise determination of the degree of stenosis and extension within the portal vein, as well as pressure measurements. Thrombotic occlusions of the portal, mesenteric, and splenic veins can be managed by mechanical thrombectomy (MT) or pharmacologic thrombolysis. Underlying occlusions because of organized or refractory thrombus or fixed venous stenosis are best corrected by balloon angioplasty and stent placement. Access into the portal venous system can also be established through creating a transjugular intrahepatic portosystemic shunt (TIPS). Creating a TIPS is also important in the setting of PVT associated with cirrhosis to decompress portal hypertension and improve portal venous flow. PVT involving the portal, splenic, and/or mesenteric veins can also complicate a preexisting TIPS in which case the shunt can be readily used as therapy access. Several techniques may be used to recanalize the shunt and portal venous system, including thrombolytic therapy, balloon angioplasty/embolectomy, suction embolectomy, basket extraction of clots, and mechanical thrombectomy with a variety of devices. Advantages of MT include the potential to rapidly remove thrombus without the need for prolonged thrombolytic infusions, and reducing the potential life-threatening complications of thrombolytic therapy. Possible drawbacks include the risk of intimal or vascular trauma to the portal vein, which may promote recurrent thrombosis.     

Use of Ga-68 DOTATATE PET/CT to confirm portal vein tumor thrombosis in a patient with pancreatic neuroendocrine tumor

A 37-year-old man complained of increasing severity and frequency of abdominal pain over a 2-year period. Initial contrast-enhanced computed tomography of the abdomen demonstrated diffuse enlargement of the pancreas associated with a filling defect in the portal vein, splenomegaly with wedge-shaped peripheral splenic hypodensities and multiple hepatic hypodensities. Findings were suggestive of a pancreatic malignancy complicated by hepatic metastases, splenic infarcts, and portal vein thrombosis. We describe the use of gallium-68 DOTA-DPhe1, Tyr3-octreotate positron emission tomography/computed tomography (Ga-68 DOTATATE PET/CT) in confirming the diagnosis of a pancreatic neuroendocrine tumor with portal vein tumor thrombosis.     

Case report. Unusual presentation of a pancreatic mass in an infant: pancreatic haemangioendotheliomatosis

Primary pancreatic tumours are extremely rare in children. We report a case of a 5-month-old male with a diffuse invasive tumour of the head of the pancreas. The tumour demonstrated peripancreatic extension into the porta hepatis, which occluded the portal vein and invaded the superior mesenteric artery. It was found to be haemangioendotheliomatosis of the pancreas. Imaging, pathological findings and a brief relevant classification of haemangioma are discussed.     

经皮脾静脉途径联合TIPS治疗伴海绵样变性的门静脉血栓

目的 探讨经皮脾静脉途径联合TIPS治疗伴海绵样变性的门静脉血栓的可行性、安全性和疗效.方法 对3例门静脉血栓伴门脉海绵样变性患者行经皮脾穿脾静脉途径开通门静脉,联合TIPS重建门静脉分流道.随访22～40个月,观察治疗效果、支架通畅情况、肝功能变化和并发症.结果 3例均成功.其中1例支架经由显著扩张的海绵样变性的侧支放置,术后7个月内出现2次肝性脑病前期症状,药物治疗后症状消失.1例患者于术后6个月内出现持续性的胆红素增高,最高总胆红素为88.2μmoL/L,直接胆红素68.7 μmoL/L.予以保肝、降黄治疗后总胆红素维持在(44.4±11.6)μmol/L,直接胆红素(29.7±12.8)μmol/L.较术前无显著变化.第3例术后恢复良好.3例无术中并发症,术后随访22～40个月,支架血流通畅,未再发静脉曲张出血.结论 在有限的治疗伴有海绵样变性的门静脉血栓的方法选择中,经皮脾穿刺脾静脉途径开通门静脉,联合TIPS是安全可行和有效的,虽然技术要求上更困难和更具挑战性.     

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

AIM: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.     

MR portal venography: preliminary results of fast acquisition without contrast material or breath holding

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the feasibility of using the steady-state free precession (SSFP) sequence to perform magnetic resonance (MR) venography of the portal venous system without the use of contrast material or breath holding. MATERIALS AND METHODS: Eleven patients underwent MR venography with the SSFP technique. Coronal three-dimensional images were obtained with respiratory triggering. Contrast material and respiratory suspension were not used. All patients had recently undergone at least one other imaging study (conventional angiography, transhepatic portal venography, ultrasound, or contrast-enhanced computed tomography), and these findings were correlated with those from MR venography. The structures evaluated were the main portal vein, right portal vein, left portal vein, superior mesenteric vein, and splenic vein. RESULTS: MR venography with SSFP accurately depicted the status of these veins in all cases except one. In this patient, MR venography depicted portal vein thrombus but could not indicate that it was tumor thrombus. CONCLUSION: MR venography with SSFP accurately depicted the portal venous system in 10 of 11 patients without the use of respiratory suspension or contrast material.     

多层螺旋CT对胰源性门静脉高压的诊断价值

目的探讨多层螺旋CT腹部增强扫描在诊断胰源性门静脉高压(PSPH)中的价值。方法对15例临床疑诊胰腺体尾部病变累及门静脉系统的患者的增强CT资料进行回顾性研究,观察门静脉系统形态改变,并测量胃冠状静脉、门静脉、脾静脉、肠系膜上静脉内径。结果急慢性胰腺炎及胰腺癌侵犯或压迫脾静脉,血液向门静脉回流受阻,致其远端显影不佳,近端血管扩张以及侧支循环形成最终导致胰源性门静脉高压症。结论多排螺旋CT可连续观察侧支循环走行,清晰显示病变与邻近结构关系,为胰源性门脉高压患者提供血管形态、病因诊断等多方面有价值信息,并为临床诊断和治疗提供客观的影像学依据。     

胰腺癌血管侵犯的不同CT诊断标准的研究

目的:研究胰腺癌血管侵犯的不同CT诊断标准的优劣。材料和方法:回顾性收集我院经多层螺旋CT三期动态增强扫描并经手术病理证实为胰腺导管细胞癌的36例患者。CT轴位图像结合CTA(以MIP和VR方法重建)以及多平面重建(MPR)分别对这些血管以Loyer和Lu血管分级CT标准进行分级,并和手术结果进行对照,分别作出受试者工作特性曲线(ROC),比较曲线下面积的差异。另外,运用Lu的CT诊断标准分别评价胰周动脉和静脉受侵的准确性、灵敏度、特异度、阳性预测值、阴性预测值、Youden指数,研究Lu的CT诊断标准对动静脉分级的差异。结果:Loyer和Lu的CT诊断标准所得的灵敏度、特异度分别为84.5%、86.0%、81.4%、91.8%,两个诊断标准的ROC曲线下面积分别为0.886、0.912,经统计学检验无明显差异。应用Lu的CT诊断标准,胰周动静脉受侵的阳性预测值分别为57.1%和71.0%。结论:分别以Loyer和Lu血管分级CT标准对胰腺癌胰周血管侵犯进行分级,两者的诊断价值相同,Lu的CT诊断标准的最佳诊断分界点应在90°-180°之间,此外,它对胰周动脉的价值要比静脉差。     

Mesenteric vein thrombosis: CT identification

Superior mesenteric vein thrombosis was identified on computed tomographic scans in six patients. In each case, contrast-enhanced scans showed a high-density superior mesenteric vein wall surrounding a central filing defect. Four of the six patients had isolated superior mesenteric vein thrombosis. A fifth patient had associated portal vein and splenic vein thrombosis, and the sixth patient had associated portal vein and inferior vena cava thrombosis. The diagnosis of superior mesenteric vein thrombosis was confirmed by angiography in two patients and by surgery in a third. One of the six patients had acute ischemic bowel disease. The other five patients did not have acute ischemic bowel symptoms associated with their venous occlusion. This study defines the computed tomographic appearance of mesenteric vein thrombosis. A dense venous wall surrounding a central lucency representing blood clot was present in all six cases.     

Local extension of pancreatic carcinoma: assessment with thin-section helical CT versus with breath-hold fast MR imaging--ROC analysis.

PURPOSE: To compare contrast material-enhanced thin-section helical CT with breath-hold contrast-enhanced MR imaging for sensitivity in the detection of pancreatic adenocarcinoma and for accuracy in local tumor staging. MATERIALS AND METHODS: Fifty-seven patients (37 men, 20 women aged 42-28 years) suspected of having pancreatic adenocarcinoma were examined. The final diagnosis was confirmed at surgery to be pancreatic cancer in 31 patients; the other 26 patients were deemed not to have pancreatic cancer. All patients underwent both CT and MR imaging (turbo spin-echo and fast low-angle shot) studies. Image quality and pancreatic enhancement were subjectively evaluated. All CT scans and MR images were assessed by two independent observers by using a five-point scale for the detection of tumor and of invasion into the peripancreatic tissue, portal vein, and/or peripancreatic artery. Receiver operating characteristic curves for CT and MR imaging were analyzed. RESULTS: At visual analysis, pancreatic enhancement at CT and at MR imaging was comparable, but depiction of vessels was superior at helical CT. Detectability of tumor was comparable. Helical CT was significantly superior to MR imaging in diagnostic imaging of invasion into the peripancreatic tissue, portal vein, and/or peripancreatic artery (P < .01). CONCLUSION: Thin-section dynamic CT is more sensitive than MR imaging for detection of peripancreatic and vascular invasion in patients with pancreatic cancer.     

Transjugular intrahepatic portosystemic shunt after previous recanalization of a chronically thrombosed portal vein via a transmesenteric approach

We report a cirrhotic patient with complete occlusion of the portal vein with marked cavernous transformation due to chronic thrombosis in whom a transjugular intrahepatic portosystemic shunt (TIPS) was successfully created after direct minilaparotomy mesenteric vein catheterization, lysis and aspiration of the thrombus, and stenting in the portal vein. The methods used, we believe, provide a new technique for performing TIPS in chronically thrombosed portal veins in which previously no effective surgical therapeutic options were available. Received: 0/00/00/Accepted: 0/00/00