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.     

Hepatic arterial flow distribution with hepatic neoplasms: significance in infusion chemotherapy

Hepatic artery radionuclide flow studies and hepatic angiography in eight patients with various hepatic neoplasms were evaluated to determine the patterns of arterial flow distribution in the presence of portal vein occlusion. Increased hepatic arterial blood flow to the lobe or segment supplied by the occluded portal vein was observed in all patients. This phenomenon must be taken into account when positioning catheters for hepatic artery infusion chemotherapy; while it may improve the flow of chemotherapeutic agents to tumors located in the area of an occluded portal vein branch, it may also result in diversion of flow to the normal hepatic parenchyma away from tumors occupying the hepatic segments with patent portal venous flow. Hepatic angiography and radionuclide flow studies provide the necessary information for correct positioning of hepatic artery infusion catheters.     

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.     

暂时阻断肝静脉后肝脏的血流改变及其意义：CT影像学研究

目的 研究犬肝静脉阻断后肝脏血流改变,并评估该技术在肝癌介入治疗中的应用价值。材料与方法 对6只犬行肝静脉球囊导管阻断,应用螺旋CT行肝脏双期扫描和同层动态增强扫描。结果 肝静脉受阻肝叶密度明显低于未阻肝叶,二者形成明显的分界,门静脉逆行增强显影,受阻肝叶肝实质及门静脉增强的平均峰值时间显滞后于未受阻者。结论 暂时阻断肝静脉后受阻区域总的血流量减少,血流速度变缓,门静脉变为引流静脉。暂时阻断肝静脉行肝动脉化疗栓塞术和局部高温固化疗效是一项有临床应用前景的技术。     

Angiographic Findings in Biliary Atresia

We present the angiographic findings of 46 patients with biliary atresia (BA). There were 25 males and 21 females, with a mean age of 22.5 months (range - 1.5 to 141 months). Hepatic and mesenteric angiography were obtained as part of a liver transplantation work-up or as part of the treatment of clinical events. All patients had a histological diagnosis of BA. The portal vein was patent in 43 patients, with a mean size of 4.1 mm, using the arterial catheter as comparison. Portal hepatopetal flow was observed in 20 patient and hepatofugal flow was observed in 21 patients. Presence of gastroesophageal varices was observed in 41 patients. The hepatic artery was enlarged in all patients. In all 46 patients studied, the intrahepatic peripheral hepatic artery branches presented with irregularities in contour, including encasement, strictures, dilatation and angulation, and images suggestive of peripheral occlusion. Angiographic vascular tuft-like blush surrounding the irregular or occluded peripheral arterial segments was observed in 40 patients. The injection of Microfil ® in one case showed a marked vascular proliferation within the portal tract, apparently derived from arterial and portal connections, filling the entire portal space. We conclude that the presence of angiographically demonstrable perivascular arterial tufts in the periphery of the hepatic arterial circulation is a common finding in cases of BA, and may be a characteristic diagnostic angiographic finding.     

Prevention of hepatic infarction as acute-phase complication of TIPS by temporary balloon occlusion in a patient with primary myelofibrosis

Severe acute liver dysfunction occurred following transjugular intrahepatic portosystemic shunt (TIPS) creation in a patient with massive ascites due to portal hypertension associated with primary myelofibrosis. On US and TIPS venography, we considered that the acute liver ischemia was induced by TIPS. To avoid diffuse hepatic infarction and irreversible liver damage, a balloon catheter was inserted transjugularly into the TIPS tract and occluded it to increase portal venous flow toward the peripheral liver parenchyma. The laboratory data indicating hepatic dysfunction were improved after the procedure. We should pay attention to the possible occurrence of acute hepatic ischemia and infarction after TIPS creation even in a case of noncirrhotic portal hypertension. In such cases, temporary balloon occlusion of TIPS is an effective therapeutic method, probably as a result of inducing the development of arterial compensation through the peribiliary plexus.     

Hemodynamic and morphologic changes after portal vein embolization: differential effects in central and peripheral zones in the liver on multiphasic computed tomography

OBJECTIVE: To evaluate hemodynamic and morphologic effects in the liver after portal vein embolization (PVE). METHODS: Hepatic computed tomography scans of 7 patients who had undergone preoperative PVE were retrospectively reviewed. Pre- and post-PVE computed tomography densities were evaluated for the unenhanced, late arterial, and portal venous phases in peripheral and central hepatic regions and in the 3 main hepatic veins. Relative changes in areas in these regions were assessed in 5 evaluable patients with serial post-PVE scans. RESULTS: During the late arterial phase, enhancement was significantly higher after PVE than it was before PVE in the peripheral hepatic regions, and it was higher in the peripheral regions than in the central regions. Enhancement was also significantly higher in the right main hepatic vein than in the middle and left hepatic veins during the late arterial phase. The ratio of areas of the peripheral/central regions decreased significantly after PVE. CONCLUSIONS: Zonal enhancement in the late arterial phase changed after PVE and seemed to be associated with differential parenchymal atrophy. We speculate that the hepatic arterial supply increases peripherally and that peribiliary/periportal plexuses maintain the portal supply centrally.     

门静脉癌栓肝脏血供变更的CT表现

目的探讨门静脉癌栓血流动力学变化及肝脏周边区动脉期异常强化的发生机制.方法回顾分析30例经CT和血管造影证实的中晚期肝癌28例,转移癌2例同时并发门静脉癌栓形成的影像学资料.结果30例门静脉癌栓中在主干、左、右支同时存在的有18例,主干癌栓3例,左、右支癌栓9例.门静脉海绵样变26例,CT表现为肝门、肝裂、胆囊窝增粗成团的血管影.在30例中,肝脏周边区动脉期异常强化10例.结论门静脉癌栓后侧枝循环形成海绵样变,仍能维持肝脏的血供,肝脏周边区动脉期异常强化提示肝脏血供变更,门静脉血供减少,动脉血供代偿增加.     

Multi-detector row helical CT angiography of hepatic vessels: depiction with dual-arterial phase acquisition during single breath hold

PURPOSE: To determine by using multi-detector row computed tomography (CT), in a triphasic hepatic dynamic study, which included single breath-hold dual-arterial phase acquisition, the accuracy and frequency of visualization of the small hepatic arterial and portal venous anatomy with angiographic correlation. MATERIALS AND METHODS: In 62 patients, pre- and postcontrast triphasic helical CT were performed by using a multi-detector row CT scanner, with 2.5-mm detector row collimation, at a pitch of 6. The first and second arterial phases were performed during a single breath hold. One reader, blinded to the results of the angiography, reviewed the first arterial phase images on a cine display to assess hepatic arterial anatomy. Visualization of the portal vein and its branches was assessed by using second arterial and portal venous phase images. RESULTS: Major arterial trunks (celiac, hepatic, superior mesenteric, and left gastric) were depicted in all cases. Visualization of small arteries was as follows: right and left hepatic, 62 (100%) of 62; middle hepatic, 52 (87%) of 60; cystic, 47 (90%) of 52; right gastric, 50 (89%) of 56; and right and left inferior phrenic, 57 (92%) and 55 (89%) of 62, respectively. Subsegmental or more peripheral branches of the portal vein were depicted in 83% of cases during the second arterial phase and in 96% during the portal phase. There was no difference in degree of visualization in these two phases. CONCLUSION: Multi-detector row CT angiography was able to depict the hepatic vascular anatomy.     

Transhepatic Preoperative Portal Vein Embolization Using the Amplatzer Vascular Plug: Report of Four Cases

The Amplatzer Vascular Plug (AVP) is a device originally intended for arterial and venous embolization in peripheral vessels. From December 2004 to March 2007 we implanted a total of 8 AVPs in the portal venous system in our institution for preoperative portal vein embolization in 4 patients (55–71 years) prior to right hemihepatectomy. AVP implantation was successful in all patients. Total occlusion of the embolized portal vein branches was achieved in all patients. There were no major complications associated with the embolization.     

Preoperative evaluation of the entire hepatic vasculature in living liver donors with use of contrast-enhanced MR angiography and true fast imaging with steady-state precession

PURPOSE: To preoperatively assess the entire hepatic vasculature in living related liver donors with use of a combination of contrast material-enhanced magnetic resonance (MR) angiography and true fast imaging with steady-state precession (FISP). MATERIALS AND METHODS: Twenty-five living potential liver donors were examined preoperatively on a 1.5T Siemens Sonata system. Twenty-four underwent surgery and two had catheter angiography performed to delineate complex anatomy. Contiguous 5-mm-thick, sub-second true FISP images of the liver were initially obtained during breath-holding in axial and coronal planes (repetition time [TR]/echo time [TE], 3.2/1.6; flip angle, 70 degrees ). MR angiography was performed with use of a three-dimensional (3D) gradient-echo fast low-angle shot (FLASH) pulse sequence (TR/TE, 3.0/1.2; flip angle, 25 degrees ), with 40 mL of Gadolinium DTPA injected at a rate of 2 mL/sec. One precontrast and two postcontrast coronal 3D volumes were acquired, each in a 20-second breath-hold, and two subtracted 3D sets were calculated. Arterial anatomy was assessed with use of maximum-intensity projection, volume rendering, and multiplanar reformatting algorithms. Hepatic and portal venous anatomy was evaluated with use of the true FISP images and the venous phase of the MR angiogram. Visualization of hepatic arterial branches was noted. Visualization of portal vein branches was scored on a scale of 0-5. The presence of anatomic variants was noted. Vascular anatomy was confirmed at the time of surgery and at catheter angiography. RESULTS: Segmental branch vessels were visualized on MR angiography in the majority of cases. The segment four branch was identified in 96% patients. Variant arterial anatomy was seen in 50% of patients. MR angiography detected 10 of 11 arterial variants found at surgery and angiography. Visualization of portal vein branches was generally higher with true FISP compared to MR angiography. Twenty-four percent of patients had variant portal venous anatomy. Caudal hepatic veins were identified in 60% of patients, of which eight were significant (>5 mm). Hepatic and portal venous anatomy was accurately predicted by true FISP and MR angiography in all patients who went on to undergo surgery. CONCLUSION: Preoperative imaging with use of a combination of contrast-enhanced MR angiography and true FISP provides a comprehensive assessment of the entire hepatic vasculature in living liver donors.     

遗传性出血性毛细血管扩张症肝脏病变的 MDCT 影像学特征

目的：探讨遗传性出血性毛细血管扩张累及肝脏病变的M DC T影像学特征及临床意义。方法回顾分析9例经临床明确诊断的遗传性出血性毛细血管扩张累及肝脏的影像学资料并总结其影像特征。结果①肝动脉‐肝静脉分流4例：动脉期见增粗迂曲的肝动脉及提前显影的肝静脉;肝实质弥漫性分布小斑片状边缘模糊强化灶,门脉期等密度。其中3例肝门区胆管轻度扩张;②肝动脉‐门静脉分流1例：动脉期见扩张迂曲的肝动脉及提前显影的扩张门静脉;肝实质少量小斑片状强化灶,门脉期等密度;③肝动脉‐肝静脉分流合并肝动脉‐门静脉分流3例,动脉期肝动脉迂曲扩张,肝静脉和门静脉提前显影;肝实质弥漫性分布小斑片状强化灶,门脉期等密度;④门静脉‐肝静脉分流1例：动脉期未见扩张肝动脉,门脉期见扩张门静脉及其远端分支旁小斑片状强化灶,延迟期呈稍高密度。结论遗传性出血性毛细血管扩张症累及肝脏的CT影像表现具有特征性,充分认识其影像表现并结合临床对其诊断及鉴别诊断具有重要意义。     

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.     

Spontaneous intermittent reversal of blood flow in intrahepatic portal vein branches in cirrhosis of the liver

The intrahepatic portal venous flow in cirrhosis of the liver was evaluated by percutaneous transhepatic portography and hepatic arteriography. Spontaneous reversal of flow in segmental portal vein branches was documented. Changes in hepatic arterial inflow and portal venous pressure may result in intermittent changes in the direction of flow in segmental portal venous branches within the cirrhotic liver. Segmental reversal of blood flow seems to be the precursor of total hepatofugal portal flow.     

Hepatic venous pressure gradients measured by duplex ultrasound

AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r=0.83, P<0.0001) and with the Child-Pugh score (r=0.63, P<0.0001). An acceleration index cut-off value of 1m.s(-2) provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient>12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r=0.45,P=0.01) and portal vein velocity (r=0.40,P=0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension.     

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.     

Dynamic CT scanning of the normal canine liver: interpretation of time density curves resulting from an intravenous bolus injection of contrast material

Seven adult male mongrel dogs were monitored by electromagnetic flow probes and string occluders around the hepatic artery and portal vein. Then, time density curves of the liver, aorta and portal vein were recorded using dynamic CT scanning following the bolus injection of contrast material into a peripheral vein (n = 7) and a mesenteric vein branch (n = 5). Information on total hepatic blood flow could not be obtained from the mesenteric vein injection. The hepatic time density curve could, however, be broken into its two components, hepatic arterial and portal venous flow contribution, by selective ligation of the hepatic artery or portal vein. It could be demonstrated that the arterial component of liver enhancement reached its peak at the end of the aortic wash-out of contrast material. Thus, the hepatic time-density curve could be broken in its two components by superimposing the aortic time density curve onto the hepatic curve. An attempt was made to estimate relative portal venous blood flow by using the slopes or the peaks of both components of the hepatic curve. Using the slopes of the hepatic curve resulted in a consistent underestimation of portal venous blood flow, whereas the peaks gave an estimate of portal venous flow with an accuracy within +/- 8%.     

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.     

暂时阻断肝静脉后行肝动脉化疗栓塞术治疗肝癌的药代动力学研究

目的对照单纯经肝动脉化疗栓塞术（ＴＡＣＥ），研究暂时阻断肝静脉后行肝动脉化疗栓塞术（ＴＡＣＥＴＨＶＯ）治疗原发性肝癌的药代动力学变化。方法为了进行药代动力学研究，随机将病人分为两组，ＴＡＣＥ组和ＴＡＣＥＴＨＶＯ组。采用高效液相色谱仪测定肝静脉和外周静脉血中５氟尿嘧啶（５Ｆｕ）的血药浓度，进行药代动力学分析。结果肝静脉和外周静脉血中５Ｆｕ的曲线下面积比值，ＴＡＣＥＴＨＶＯ组明显大于ＴＡＣＥ组；肝静脉血中５Ｆｕ的峰浓度，ＴＡＣＥＴＨＶＯ组明显高于ＴＡＣＥ组。同组中肝静脉和外周静脉的５Ｆｕ浓度趋向一致时间，ＴＡＣＥＴＨＶＯ组３０分钟，ＴＡＣＥ组为６分钟。结论暂时阻断肝静脉后行肝动脉化疗栓塞术可明显提高肿瘤局部的药物浓度，延长作用时间，加倍提高了抗肿瘤的效果，该法在临床上有很好的应用价值     

Multiphase hepatic CT with a multirow detector CT scanner

OBJECTIVE: The aim of this study was to evaluate a new injection-acquisition technique performed using a multirow detector CT scanner for separation of three distinct hepatic circulatory phases (hepatic artery, portal venous inflow, hepatic venous) and to determine which of these phases is optimal for detecting hypervascular neoplasm. MATERIALS AND METHODS: Two sequential acquisitions were performed during a single breath-hold followed by a third acquisition beginning 60 sec after injection. Injection-to-scan delay for the first acquisition was the individual patient's circulation time, which was determined by a preliminary mini bolus. The mean attenuation of the upper abdominal aorta, portal vein, and hepatic parenchyma were determined for each imaging pass in 20 patients with cirrhosis and 20 patients without cirrhosis. Tumor-to-liver contrast for hypervascular primary and metastatic neoplasm was evaluated in a different set of 16 cirrhotic patients and nine noncirrhotic patients. Three-dimensional CT arteriograms were obtained from first-pass data. RESULTS: Three distinct circulatory phases (hepatic artery, portal vein inflow or late arterial, and hepatic venous) were seen in cirrhotic and noncirrhotic patients. Maximum tumor-to-liver contrast for hypervascular primary and metastatic neoplasm occurred during the second pass for both cirrhotic (p < 0.006) and noncirrhotic (p < 0. 001) patients. A three-dimensional hepatic-mesenteric CT arteriogram of normal or anomalous hepatic vessels without venous overlay was obtained from first-pass data in all patients. CONCLUSION: Rapid-sequence hepatic helical CT allows selection of the optimal time interval for hypervascular tumor detection. A new paradigm for rapid hepatic CT acquisition-namely, hepatic arterial, portal vein inflow, and hepatic venous phases-is recommended to replace hepatic artery dominant and portal venous phases.