Small veins entering the liver

It is important to recognize and understand focal fatty infiltration and pseudolesions of the liver mimicking liver tumors on CT during arterial portography or helical-CT images. These conditions are caused by venous flow outside the main portal vein. Unless this is borne in mind, incorrect diagnosis and management may follow. This article demonstrates the appearance of the parenchymal changes caused by systemic venous flow and location of the systemic veins entering the liver parenchyma.     

螺旋CT门静脉成像诊断门脉受侵的价值

目的 评价螺旋CT门静脉成像诊断门脉受侵的准确性。材料与方法 75例患者于肝脏术前进行了螺旋CT静脉成像,总共评价了225支门静脉主干,左支及右支的受侵情况,包括包需求量、闭塞和癌栓形成,螺旋CT门静脉成像的诊断结果与手术,病理相对照。结果 螺旋CT门静脉成像发现了43支受侵中的42支和182支无受侵中的180支,SCTP判断门静脉受侵的总敏感性为97.7%,特异性为98.9%,阳性预测值为95.5%,阴性预测值为99.4%。结论 螺旋CT门静脉成像在诊断门静脉受侵中有很高的准确性。     

Haemodynamic changes in the liver under balloon occlusion of a portal vein branch: evaluation with single-level dynamic computed tomography during hepatic arteriography

AIM: To assess haemodynamic changes in the liver under temporary occlusion of an intrahepatic portal vein. MATERIALS AND METHODS: Between February 2000 and October 2004, 16 patients with hepatobiliary disease underwent single-level dynamic computed tomography during hepatic arteriography (SLD-CTHA) under temporary balloon occlusion of an intrahepatic portal vein. All patients needed percutaneous transhepatic portography for therapy of their disease. SLD-CTHA was undertaken to clarify the time-attenuation curve influenced by portal vein occlusion, and it was performed continuously over a period of 30s. The difference in absolute attenuation of the liver parenchyma in segments with occluded and non-occluded portal vein branches was determined by means of the CT number, and the difference in absolute attenuation of the occluded and non-occluded portal veins themselves was also evaluated. RESULTS: SLD-CTHA demonstrated a demarcated hyperattenuation area in the corresponding distribution of the occluded portal vein branch. The attenuation of the liver parenchyma supplied by the occluded portal vein was significantly higher than that in the non-occluded area (p<0.01). The balloon-occluded portal branch enhancement in 15 of 16 cases (94%) appears due to arterio-portal communications. Failure to evaluate a remaining case for portal branch enhancement was due to absence of a visualized portal branch in the section. CONCLUSION: Under temporary occlusion of an intrahepatic portal vein, hepatic angiography produced enhancement of the occluded portal branches and their corresponding parenchymal distribution; this finding is considered consistent with the presence of arterio-portal communications.     

Three-dimensional portography using multislice helical CT is clinically useful for management of gastric fundic varices

OBJECTIVE: This study seeks to evaluate three-dimensional (3D) helical CT portography as a tool for examining patients with gastric fundic varices. SUBJECTS AND METHODS: We compared 3D helical CT portography and conventional angiographic portography in 30 consecutive patients with gastric fundic varices. We assessed whether 3D helical CT portography is useful in selecting patients and in evaluating the results of balloon-occluded retrograde transvenous obliteration. RESULTS: Three-dimensional helical CT portography simultaneously depicted second or third branches of the intrahepatic portal vein and provided images of entire portosystemic collaterals. On 3D helical CT portography, gastric fundic varices were seen in 30 patients (100%), left gastric veins in 19 (63%), posterior gastric veins or short gastric veins in 28 (93%), gastrorenal shunts in 27 (90%), paraumbilical veins in three (10%), and inferior phrenic veins in two patients (7%). Findings of 3D helical CT portography and conventional angiographic portography were in close agreement. However, in four patients, posterior gastric veins or short gastric veins were not seen on conventional angiographic portography images of the spleen, but they were clearly revealed on 3D helical CT portography. Treatment was successful in all patients except one. Three-dimensional helical CT portography could easily evaluate therapeutic results. CONCLUSION: Three-dimensional helical CT portography proved so effective that it can be considered a less invasive alternative than conventional angiographic portography in assessing portosystemic collaterals. CT portography is useful in selecting candidates from patients with gastric fundic varices for retrograde transvenous obliteration and also in evaluating therapeutic results.     

Contrast-enhanced three-dimensional MR portography.

Three-dimensional (3D) magnetic resonance (MR) portography with contrast material enhancement is a fast means of evaluating the portal venous system that has some advantages over currently used modalities, such as digital subtraction angiography, helical computed tomography, ultrasonography, and nonenhanced MR angiography with time-of-flight and phase-contrast techniques. With contrast-enhanced 3D MR portography, a first-pass study of the mesenteric vasculature is performed after rapid bolus injection of gadopentetate dimeglumine; a 3D fast field echo sequence is used, which can demonstrate the intrahepatic and extrahepatic portal venous system clearly. Repeated sequences after administration of gadopentetate dimeglumine allow separate demonstration of the splanchnic arteries and portomesenteric veins. The images are reconstructed by means of maximum-intensity projection postprocessing, and a subtraction technique can be used to eliminate arterial enhancement and demonstrate portosystemic shunts. The coronal source images simultaneously demonstrate parenchymal lesions of the liver, pancreas, biliary tract, and spleen. This technique is clinically indicated in portosystemic shunt, portal vein thrombosis, hepatocellular carcinoma, pancreatobiliary tumor, hepatic vein obstruction, differentiation of splanchnic arterial from portal venous disease, and gastrointestinal hemorrhage. Its limitations include allergic reactions to contrast media, inappropriate positioning of the 3D acquisition slab, respiratory motion artifacts, and pseudodissection.     

Change in the hemodynamics of the portal venous system after retrograde transvenous balloon occlusion of a gastrorenal shunt

OBJECTIVE: The purpose of our investigation was to examine changes in the hemodynamics of the liver after artificial occlusion of a gastrorenal shunt. SUBJECTS AND METHODS: Nine patients with portal hypertension underwent splenic arteriography and CT arterial portography during infusion of contrast material via the splenic artery. Images were obtained with the balloon catheter both inflated and deflated in the gastrorenal shunt, and results were compared. RESULTS: During the portal phase of splenic arteriography, the intrahepatic portal vein was more clearly seen when the balloon occluded the gastrorenal shunt. Mean CT attenuation values of branches of the intrahepatic portal vein on CT arterial portograms acquired when the balloon catheter was inflated were higher than values acquired when the balloon was deflated; however, results for the inferior vena cava were the opposite. Differences in CT attenuation values were statistically significant for the right branch of the portal vein, main portal vein, right lobe of the liver parenchyma, and inferior vena cava. CONCLUSION: Closure of large gastrorenal shunts (hepatofugal portasystemic shunts) causes the portal blood flow to switch from hepatofugal to hepatopetal, which increases the effective intrahepatic portal blood flow.     

Portal vein occlusion or stenosis in patients with hepatolithiasis: observation by multiphasic contrast-enhanced CT

AIMS: To analyze the dynamic findings of multiphasic contrast-enhanced CT in hepatolithiasis and to elucidate occlusive changes in portal veins and other associated abnormalities. METHODS: This was a retrospective study of 25 selected patients with hepatolithiasis who underwent various imaging examinations, including multiphasic contrast-enhanced CT. The following CT findings were evaluated in each of 71 hepatic segments: visualization of a calculus; biliary dilation or focal hepatic atrophy of the affected segment; areas that were abnormally enhanced in the hepatic arterial phase; degrees (normal, stenosis, occlusion) of portal vein calibre; and linear delayed enhancement along the bile-duct walls, suggesting cholangitis. RESULTS: On CT, calculi were depicted as a hyperdense structures in 61 of 71 segments (86%). Focal hepatic atrophy, which frequently accompanied CT findings suggesting compensatory hypertrophy of other segments, was seen in 50 of 71 segments (70%). Areas that were abnormally enhanced were recognized in 36 of 71 segments (51%). Stenosis or occlusion of portal venous branches was observed in 59 of 71 segments (83%), including 13 segments with occlusion. Findings indicating cholangitis were noted in 50 of 71 segments (70%). The degrees of portal vein calibre were significantly correlated with the presence of hepatic atrophy or cholangitis. CONCLUSION: Hepatolithiasis is associated with significant rates of stenosis or occlusion of adjacent portal veins as well as hepatic parenchymal changes in the affected area. Chronic deterioration of portal flow may cause these morphological changes.     

CT signs of hepatofugal portal venous flow in patients with cirrhosis

OBJECTIVE: We investigated whether CT signs can be used to predict hepatofugal flow in the main portal vein in patients with cirrhosis. MATERIALS AND METHODS: We retrospectively identified 36 patients with cirrhosis, 18 with hepatopetal and 18 with hepatofugal flow in the main portal vein, who underwent contemporaneous abdominal sonography and CT. Two independent observers evaluated the following features on the randomized CT studies: diameter of the portal, splenic, and superior mesenteric veins; spleen size; and the presence of ascites, varices, or arterial phase portal venous enhancement. These data were correlated with the flow direction seen on sonography. RESULTS: A small main portal vein was the only sign significantly (p 相似文献   

无创伤性三维门静脉双螺旋CT造影

本文报到60例三维门静脉双螺旋CT造影结果.在所有的病人该方法均能显示肠系膜上静脉、脾静脉、门静脉主干及其分支、在3例肝癌.2例肝癌术后及4例门静脉高压病人,三维门静脉双螺旋CT造影结果与肠系膜上动脉门静脉造影和外科手术所见一致,表明三维门静脉双螺旋CT造影是一种安全而又可靠的显示门静脉系统的方法.     

CT arterial portography: causes of technical failure and variable liver enhancement.

OBJECTIVE. We studied the causes of technical failure and enhancement variability encountered during CT arterial portography. MATERIALS AND METHODS. CT arterial portograms and digital arteriograms were obtained via the superior mesenteric artery before partial liver resection in 43 patients with malignant tumors. These studies were reviewed for causes of technical failure and variable enhancement. RESULTS. Eleven (26%) of 43 procedures were technical failures. Causes of failure included aortic injection after catheter dislodgement (four), dense hyperenhancement associated with laminar flow in the portal vein produced by rapid venous return from a selective injection into a proximal branch vessel of the superior mesenteric artery (two), premature scanning beginning at the iliac crest (two), reflux into a replaced right hepatic artery (one), hepatic arterial enhancement via the pancreaticoduodenal arcade (one), and portal hypertension (one). Of the 32 remaining studies, 28 showed areas of parenchymal hypoenhancement or hyperenhancement. Causes of variable enhancement included impaired portal vein perfusion from mass effect of the tumor, laminar flow in the portal vein, and focal fatty infiltration. CONCLUSION. Technical failures and enhancement variability are common in CT arterial portography. Factors leading to technical failure include catheter choice and position, portal hypertension, and operator error.     

螺旋CT门静脉成像评价门脉高压的价值

目的 评价螺旋CT门静脉成像（SCTP）显示门静脉高压的价值。材料与方法 51例患者分别进行了SCTP和常规门静脉造影,间隔时间0－3天。其中42例为肝癌患者伴或不伴门静脉高压,9例为单纯肝硬化伴门静脉高压患者。分析SCTP图像上门静脉主干及左、右分支的开放性;侧支循环发生的部位和分布范围,结果与常规门静脉造影（直接和间接法）相对照,评价两者的符合情况。结果 在51例患者共153支门静脉主干和左、右分支中,SCTP显示107支通畅中的104支,46支充盈缺损、闭塞中的44支,总符合率为96．7％（148／153）。除1例冠状静脉曲张及1例脐静脉开放未显示外,SCTP清楚显影其余侧支血管,总符合率为95．3％（41／43）。结论 SCTP与常规门静脉造影诊断符合率高,能准确显示门静脉开放性和门静脉高压侧支循环分布情况,基本能取代有创性的传统门静脉造影术。     

Intrahepatic Left to Right Portoportal Venous Collateral Vascular Formation in Patients Undergoing Right Portal Vein Ligation

Purpose

We investigated intrahepatic vascular changes in patients undergoing right portal vein ligation (PVL) or portal vein embolization (PVE) in conjunction with the ensuing hypertrophic response and function of the left liver lobe.

Methods

Between December 2008 and October 2011, 7 patients underwent right PVL and 14 patients PVE. Computed tomographic (CT) volumetry to assess future remnant liver (FRL) and functional hepatobiliary scintigraphy were performed in all patients before and 3 weeks after portal vein occlusion. In 18 patients an intraoperative portography was performed to assess perfusion through the occluded portal branches.

Results

In all patients after initially successful PVL, reperfused portal veins were observed on CT scan 3 weeks after portal occlusion. This was confirmed in all cases during intraoperative portography. Intrahepatic portoportal collaterals were identified in all patients in the PVL group and in one patient in the PVE group. In all other PVE patients, complete occlusion of the embolized portal branches was observed on CT scan and on intraoperative portography. The median increase of FRL volume after PVE was 41.6 % (range 10–305 %), and after PVL was only 8.1 % (range 0–102 %) (p = 0.179). There were no differences in FRL function between both groups.

Conclusion

Preoperative PVE and PVL are both methods to induce hypertrophy of the FRL in anticipation of major liver resection. Compared to PVE, PVL seems less efficient in inducing hypertrophy of the nonoccluded left lobe. This could be caused by the formation of intrahepatic portoportal neocollateral vessels, through which the ligated portal branches are reperfused within 3 weeks.     

Patent paraumbilical vein: anatomic and hemodynamic variants and their clinical importance.

Fifty-five of 353 patients with suspected portal hypertension studied with Doppler sonography had a patent paraumbilical vein. Of these 55 patients, 39 had the classic intrahepatic venous circulation found in Cruveilhier-Baumgarten syndrome: hepatopetal flow in all segmental portal veins and hepatofugal flow leaving the liver in a paraumbilical vein in the falciform ligament to join veins of the anterior abdominal wall. Sixteen patients had variants of the classic pattern: Flow in one or more segmental portal veins of the left lobe or the entire liver was hepatofugal. In addition, new venous channels connecting the left portal vein with the extrahepatic paraumbilical vein were found. Assessment of liver function with the Pugh score showed severe impairment in the majority of patients with a patent paraumbilical vein. Patients with the classic intrahepatic circulation had smaller esophageal varices than those with hemodynamic or anatomic variants. The presence of a patent paraumbilical vein did not prevent formation of esophageal varices in the patients studied.     

门静脉高压患者多层螺旋CT在体测量研究

目的 通过多层螺旋CT门静脉血管成像,探讨门静脉高压患者门静脉系统管径、肝脾体积、肝实质强化与病因及肝功能之间的关系.资料与方法 采用16排多层螺旋CT对126例临床和实验室指标提示门静脉高压患者和47例非门静脉高压者进行门静脉CTA,并进行胃左静脉、门静脉、脾静脉、肠系膜上静脉内径测量,肝脏、脾体积测量及门静脉期肝实质和门静脉主干CT值的测量,并用SPSS 11.0统计软件包对获得数据进行分析.结果 门静脉高压患者与正常对照组相比,门静脉内径分别为(13.73±3.36) mm和(13.61±1.90) mm,脾静脉内径分别为(10.30±3.28) mm和(9.23±1.39) mm,肠系膜上静脉内径分别为(10.83±2.03) mm和(10.46±1.32) mm,胃左静脉宽度分别为(5.10±3.49) mm和(1.48±1.59) mm,肝脏体积分别为(1189.46±305.36) cm3和(1322.40±283.81) cm3,脾体积分别为(809.37±471.14) cm3和(255.53±110.35) cm3.两组间对比有统计学意义(P＜0.05).结论 多层螺旋CT门静脉血管成像在显示门静脉高压患者相关血管形态、肝脾体积及肝实质强化等多方面能提供有价值的信息,可为临床治疗方案的选择和疗效的观察评估提供影像学依据.     

Intrahepatic arterioportal shunt: helical CT findings

The purpose of this study was to characterize the appearance of intrahepatic arterioportal shunts (APS) on two-phase helical CT, with emphasis on the importance of the hepatic arterial-dominant phase (HAP) to demonstrate perfusion disorders. We review eight cases of APS diagnosed by helical CT in our institution from January 1996 to March 1997 and describe the CT findings that established diagnosis. Five of them were confirmed by angiography. In seven (87.5 %) cases of APS we found early enhancement of the peripheral portal branches during the HAP of helical CT, whereas the superior mesenteric and splenic veins remained unenhanced. In five (62.5 %) cases of APS, transient, peripheral, triangular parenchymal enhancement was depicted during the HAP of helical CT; in four of these cases there was associated early enhancement of the portal branches. Helical CT can show perfusion alterations that might remain undiagnosed with conventional CT. An understanding of the hemodynamic changes that occur in APS can help in the interpretation of focal transient hepatic parenchymal enhancement and to differentiate APS from hypervascular tumors. We believe that the helical CT findings described herein are characteristic enough to suggest the diagnosis of APS. Received: 9 February 1998; Revision received: 25 May 1998; Accepted: 7 September 1998     

三维对比剂增强MR门静脉成像与直接门静脉造影术对照

目的通过与直接门静脉造影术的比较，评价三维对比剂增强MR门静脉成像（3D CE MRP）的准确性。方法26例患者行3D CE MRP和直接门静脉造影检查。分析3D CE MRP上门静脉主干、肝内左右分支的开放性和侧支循环发生情况，其结果与直接门静脉造影对照，评价两者符合情况，并分析两者不符的原因。结果3D CE MRP和直接门静脉造影显示门静脉主干的结果完全一致。对肝内门静脉分支，有21例2种检查结果符合，但有5例不符。1例肝右叶巨大肿瘤，3D CE MRP显示门静脉右后支闭塞，但直接门静脉造影显示明显狭窄。3例左叶肝癌患者，3D CE MRP显示门静脉左支闭塞，但直接门静脉造影显示其近段狭窄和远端闭塞。另有1例肝癌患者，3D CE MRP显示门静脉左支矢状段小癌栓，而直接门静脉造影却未能显示。除1例脐静脉重开由于扫描范围较小未显示之外，3D CE MRP显示侧支循环的结果和直接门静脉造影相符。结论多数病例，3D CE MRP的显示结果与直接门静脉造影符合。3D CE MRP在鉴别肝内门静脉分支狭窄或闭塞时有一定限度，而在显示门静脉小栓子方面却有优势。     

多层螺旋CT门静脉造影的临床应用

目的:探讨多层螺旋CT门静脉造影(MSCTP) 的成像方法及其临床应用价值.材料和方法:110例临床推荐行腹部增强扫描的患者.运用最大密度投影(MIP)和容积重建(VR)两种后处理成像方法,10例增加曲面重建(CPR).结果:MSCTP能很好显示肝静脉和门静脉系统的全貌及其与病变之间的空间解剖关系,直观地评价门静脉的位置、轮廓、有无门静脉受侵或癌栓形成, 了解门静脉高压侧支循环的分布范围和程度.结论:MSCTP是肝静脉和门静脉无创性检查的可靠方法, 有较高的临床应用价值.VR比MIP重建的血管图像更优.     

Altered hepatic hemodynamics caused by temporary occlusion of the right hepatic vein: evaluation with Doppler US in 14 patients

PURPOSE: To evaluate with Doppler ultrasonography (US) the altered hepatic hemodynamics caused by temporary occlusion of the right hepatic vein. MATERIALS AND METHODS: The study group consisted of 14 patients being considered for hepatic arterial infusion or transarterial embolization. In all patients, maximum peak velocity of the blood flow in the right portal vein was measured with Doppler US before and during the occlusion of the right hepatic vein. In 13 patients, color Doppler US was performed to evaluate Doppler signal in the portal venous branch in the occluded area before and during occlusion. Average peak velocity in the right hepatic artery in eight patients was measured by using a transducer-tipped guide wire before and during occlusion. RESULTS: Maximum peak velocity of the right portal vein significantly decreased with occlusion (P <.01). Hepatic venous occlusion changed the Doppler signal in the portal venous branch in the occluded area from hepatopetal to no signal in 10 patients; to weakened hepatopetal in two; and to hepatofugal in one. Average peak velocity of the right hepatic artery showed a decrease or plateau for 15-30 seconds after the start of occlusion and then a rapid increase to reach a plateau at around 75-90 seconds, with 1.5-2 times as much velocity as that before occlusion. CONCLUSION: Increase in hepatic arterial velocity is accompanied by a decrease in the portal velocity with temporary occlusion of the right hepatic vein; the expected increased drainage through the portal vein was almost undetectable.     

Percutaneous transhepatic sclerotherapy for bleeding ileal varices associated with portal hypertension and previous abdominal surgery

A 75-year-old man with portal hypertension was referred to our institution because he suddenly began to pass a large amount of tarry stool. Arterial portography and computed tomography (CT) during arterial portography via the superior mesenteric artery, using a unified 64-slice multidetector row CT and angiography system, revealed bleeding ileal varices. The varices were supplied blood by a single ileal vein and drained by dilated veins in the abdominal wall. The bleeding was successfully arrested by performing percutaneous transhepatic sclerotherapy with 12 ml of 5% ethanolamine oleate. The blood flow to the varices was controlled by balloon occlusion, and microcoils were inserted into the varices and supplying vein. No complications or rebleeding occurred during the 13-month follow-up period, and CT images obtained during follow-up showed that the varices had disappeared.     

Portal venous system after portosystemic shunts or endoscopic sclerotherapy: evaluation with Doppler sonography

We sought to determine the usefulness of duplex Doppler sonography in the assessment of blood flow and clot formation in the portal vein in 44 patients with portal hypertension and bleeding esophageal varices who had undergone either endoscopic sclerotherapy (28 cases) or portosystemic shunt procedures (16 cases). The main, left, and right portal veins (collectively referred to as intrahepatic portal veins), superior mesenteric vein, splenic vein, and shunt were assessed for flow direction, presence of thrombi, and collaterals. Patent shunts were visualized in 12 (75%) of the 16 cases. Clot was detected in 27 (69%) of 39 intrahepatic portal veins in patients with end-to-side shunts, in six (67%) of nine intrahepatic portal veins in patients with distal splenorenal shunts, and in five (5%) of 92 intrahepatic portal veins in patients who had had endoscopic sclerotherapy. Flow in the main portal vein was hepatopetal in two (15%) of 13 patients with patent shunts (one end-to-side portacaval shunt and one distal splenorenal shunt). Flow in the main portal vein was hepatopetal in 26 (93%) of 28 patients who had had endoscopic sclerotherapy. Our data suggest endoscopic sclerotherapy preserves antegrade portal flow and results in fewer portal vein clots than surgical portosystemic shunts do. Patterns of thrombosis and flow direction vary unpredictably from patient to patient. Shunt patency should not be inferred without direct visualization of the shunt.