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.     

Hepatic arteriography under temporary hepatic venous occlusion]

Hepatic arteriography with and without temporary segmental hepatic vein occlusion was performed in 10 patients, five of whom had chronic liver injury. Hepatic arteriograms obtained during hepatic venous obstruction demonstrated significantly more peripheral and definite arterial branches in the occluded area and fewer peripheral branches in the non-occluded segment. A prolonged, dense hepatogram (sinusoidogram) showing hepatofugal opacification of the portal vein was obtained in the occluded area. Only one case with a large veno-venous anastomosis did not show these findings. Hepatic arteriograms in two cases with hepatocellular carcinoma provided clear visualization of peripheral portal branches that could act as efferent tumor vessels during regional temporary hepatic vein occlusion. Temporary hepatic venous occlusion may cause a sudden increase of hepatic arterial flow in the occluded area and transsinusoidal arterioportal communication there. This method can be useful for the diagnosis and arterial infusion or embolization therapy of hepatic diseases.     

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.     

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。     

Color Doppler sonography of the hepatic artery and portal venous system

Color Doppler sonography is an important noninvasive diagnostic tool for detecting abnormalities of the hepatic vasculature in patients with diffuse liver disease. To study its usefulness in these cases, we retrospectively reviewed the findings in 147 patients with abnormal portal venous color Doppler sonograms. This group comprised all patients with abnormal portal venous color Doppler sonograms studied from February 1987 to July 1989. Correlative imaging was not available in all cases. The sonographic diagnoses included (1) portal venous thrombosis (50 patients, 93 vessels); (2) portal-systemic or portal-portal collaterals (80 patients, 95 collaterals); (3) reversed, bidirectional, or other abnormal portal venous flow patterns (36 patients); and (4) abnormal hepatic arterial flow (20 patients). Since the results reported derive from a retrospective review without consistent correlation with other imaging studies, no appraisal of the sensitivity or accuracy of portal color Doppler sonography could be made from our data. The ability of color Doppler sonography to visualize flow without altering hemodynamics has led to several novel observations in these patients. These include increased arterial flow in states of low portal blood flow, reversal of portal flow direction postprandially, coincident reversed and hepatopetal flow in different branches of a single portal vein, and normal helical portal venous flow. These and other findings show that color Doppler sonography has enhanced our ability to detect abnormalities of the hepatic and portal venous system.     

Transient increased segmental hepatic enhancement distal to portal vein obstruction on dynamic gadolinium-enhanced gradient echo MR images

The purpose of the present study was to demonstrate the frequency of occurrence of transient increased segmental hepatic enhancement distal to portal veto obstruction in patients with a lobar (main branch) portal vein obstruction. MR images of all patients with main and lobar branch portal vein obstruction examined by dynamic gadolinium enhanced gradient echo MR images between December 1990 and July 1994 were reviewed retrospectively. All studies included T2-weighted imaging, Tl-weighted spoiled gradient echo‘fast low angle shot ([FLASH])’ and postgadolinium enhanced PLASH imaging at 1, 45, and 90 sec and 10 min. Fourteen patients were identified with portal vein obstruction which Included: six with main portal and right and left branch occlusion, six with right lobar, and two with left lobar. In the six patients with main portal vein obstruction, enhancement on 1-sec postgadolinium FLASH images was homogenous (three patients), diffusely heterogeneous (two patients), or peripherally hyperintense (one patient). In eight of eight patients with isolated obstruction of the right or left lobar portal vein, transient-increased segmental enhancement distal to portal vein occlusion was observed on immediate postcontrast images. Relatively high signal intensity of the involved segments was present on 1-sec images and liver parenchymal enhancement became more homogeneous by 45 to 90 sec in all cases. In conclusion, transient-increased segmental enhancement occurred in eight of eight patients with isolated right or left portal vein occlusion. We postulate that this effect occurs due to increased hepatic arterial blood flow in the presence of portal vein obstruction.     

Traesjugular intrahepatic portosystemic shunt in portai vein thrombosis: Role of the right gastric vein with anomalous insertion

Transjugular intrahepatic portosystemic shunt (TIPS) was performed in two patients with portal vein thrombosis. In both patients, hepatopetal flow had been maintained by an anomalous insertion of the right gastric vein (RGV) into the portal vein bifurcation and into the left portal branch respectively. In one patient, the main portal trunk could not be recanalized and the RGV was used as an accessory portal vein to place one stent for TIPS. In the other case, access through the partial portal-vein occlusion was gained and three stents were placed from the hepatic vein to the main portal vein distal to the thrombus. In portal vein thrombosis, the aberrant insertion of the RGV into the left or right portal branches may maintain patency of the intrahepatic portal system and, in case of unsuccessful recanalization of the porta, may represent the sole pathway for placing a TIPS     

Doppler and gray-scale ultrasound evaluation of morphological and hemodynamic changes in liver vascualture in alcoholic patients

OBJECTIVE: The aim of this study is to search sonographically for morphological and hemodynamic changes in hepatic and splanchnic vasculature of alcoholic patients having no signs of hepatic damage, and compare these with normal healthy subjects. METHODS: Thirty alcohol-dependent patients and 30 control subjects with no alcohol problem or hepatic impairment were included in the study. All patients were evaluated by gray-scale and spectral Doppler ultrasound. The diameter of the portal vein, portal venous velocity, peak systolic and end diastolic velocities of hepatic and superior mesenteric arteries were assessed. RI, PI and systolic/diastolic velocity ratios were also calculated. RESULTS: Portal vein cross-sectional area was greater in alcoholic patients compared to control group (P = 0.0012). Portal vein velocity, hepatic artery peak systolic and end diastolic velocity, superior mesenteric artery peak systolic and end diastolic velocity were significantly greater in alcoholic patients than in control group (P < or = 0.001). No statistically significant difference was detected between other parameters evaluated. CONCLUSION: In alcohol-dependent patients, some hemodynamic and morphologic changes occur in hepatic and splanchnic circulation, even before the signs of hepatic damage develop. These changes can be detected by means of Doppler and gray-scale sonogrsphy.     

肝内门静脉和肝静脉的解剖与变异(三维动态增强磁共振血管成像分析)

目的用三维动态增强磁共振血管成像（３ｄｉｍｅｎｔｉｏｎａｌｄｙｎａｍｉｃｃｏｎｔｒａｓｔｅｎｈａｎｃｅｄＭＲＡ,３ＤＤＣＥＭＲＡ）前瞻性地观测肝内门静脉（简称门脉）和肝静脉的解剖和变异。方法共进行１４２例门脉和肝静脉３ＤＤＣＥＭＲＡ检查。对肝内门脉和肝静脉的解剖和变异做分型,计算每一型所占总调查人数的比例,并计算右后下肝静脉的显示率。结果１４２次成像中,８例（５．６％）显示门脉呈三分叉状,７例（４．９％）门脉先分出右后支,然后上行分为左支和右前支,４例（２．８％）门脉右前支源于左支,未发现有门脉左支水平段或右支缺如,余下１２３例（８６．６％）显示正常门脉分支。绝大多数情况下（９５．１％）肝中、肝左静脉合并,而三大支肝静脉单独汇入下腔静脉仅占４．９％。右后下肝静脉的显示率为７．７％。结论肝内门脉变异并不少见。肝中和肝左静脉多合并后汇入下腔静脉。部分病人有较为粗大的右后下肝静脉。３ＤＤＣＥＭＲＡ能方便而清楚地显示上述血管的解剖和变异     

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.     

Contrast-enhanced color Doppler US in malignant portal vein thrombosis

Purpose: To assess the role of contrast-enhanced color Doppler US in the differential diagnosis of benign and malignant portal vein thrombosis.Material and Methods: Fifty-six patients with portal vein thrombosis underwent color and power Doppler US examination before and after i.v. injection of galactose-palmitic acid suspension. The criterion for diagnosing the presence and extension of thrombosis was the lack of visualization of portal vein flow in a segment of the portal vein. The criterion for diagnosing malignant portal vein thrombosis was the detection of pulsatile arterial flow, either hepatopetal or hepatofugal, in the thrombus. The US data were correlated with the types of portal vein thrombosis.Results: Among the 56 patients, there were 40 benign and 16 malignant portal thromboses. Unenhanced Doppler US detected continuous blood flow in 24 benign thromboses and pulsatile in 3 malignant thromboses. No flow, either continuous or pulsatile, was detected in 16 cases with benign thrombosis and in 13 cases with malignant thrombosis. Contrast-enhanced Doppler US allowed to assess pulsatile flow in 15 cases with malignant thrombosis (94%). The use of pulsatile flow as diagnostic criterion of malignant thrombosis yielded a sensitivity of 57% and a specificity of 95% with conventional Doppler US, whereas contrast-enhanced US achieved a sensitivity of 94% and a specificity of 100%.Conclusion: Contrast-enhanced Doppler US is a reliable diagnostic tool for assessing malignant portal vein thrombosis.     

Hepatoma, arterioportal shunting, and hyperkinetic portal hypertension: therapeutic embolization

Four patients with hepatocellular carcinoma, shunting of blood from the hepatic artery to the portal vein, and hyperkinetic portal hypertension were treated by transcatheter embolization of the hepatic artery. In three acutely bleeding patients variceal hemorrhage was controlled by the embolization. Following embolization hepatofugal portal venous flow became hepatopetal in all four patients. No serious complications were encountered. When hepatoma is complicated by arterioportal shunting and hyperkinetic portal hypertension, occlusion of the fistula by transcatheter embolotherapy can reduce the portal pressure.     

Doppler sonography of hepatic arterial blood flow velocity after percutaneous transhepatic portal vein embolization

OBJECTIVE: This study was conducted to elucidate the changes in hepatic arterial blood flow after portal vein embolization. SUBJECTS AND METHODS: We prospectively measured the flow velocity and resistive index of the common, right, and left hepatic arteries, using Doppler sonography, in 21 patients who underwent embolization of the right portal vein. The measurements were performed before and 1, 3, 5, 7, and 14 days after embolization. We assessed the changes in liver volume with a volumetric study using CT. RESULTS: After embolization, flow velocity in the common hepatic artery increased significantly (p < 0.0001). Flow velocity in the right hepatic artery also increased significantly (p < 0.0001), with a significant decrease in resistive index (p < 0.0001). The flow velocity and resistive index of the left hepatic artery were unchanged. The increase in flow velocity in the right hepatic artery significantly correlated with that in the common hepatic artery (r = 0.514, p < 0.05). The calculated volume of the embolized right hepatic lobe significantly (p < 0.0001) decreased, from 685 +/- 32 cm(3) before embolization to 568 +/- 28 cm(3) after embolization. The atrophy rate of the right hepatic lobe significantly correlated with the increase in flow velocity in the right hepatic artery (r = 0.700, p < 0.0005). CONCLUSION: Portal vein embolization induces an increase in hepatic arterial blood flow velocity in the embolized hepatic segments, resulting from an increase in common hepatic arterial flow, but not from a steal phenomenon due to decreased hepatic arterial blood flow in the nonembolized hepatic segments. This observation may be explained by the simple mechanical effect of interposing a slower flowing stream (portal flow) in the path of a faster flowing stream (arterial flow).     

Clinical use of Levovist, an ultrasound contrast agent, in the imaging of liver transplantation: assessment of the pre- and post-transplant patient

Colour Doppler US is well established for imaging of hepatic vessels in the assessment of pre- and post-liver transplant patients. Unfortunately, a full colour Doppler US examination of the portal or hepatic venous and hepatic arterial systems is frequently precluded by technical factors. Ultrasound contrast agents are useful in enhancing vascular Doppler signal and play an important role in liver transplantation assessment. A series of patients with vascular problems illustrates the role of US contrast in the pre-transplant candidate, where portal vein patency and direction of flow is assessed, presence of portal vein thrombus is confirmed and cavernous transformation demonstrated. Occlusion of hepatic veins in Budd-Chiari syndrome is confidently confirmed. Following liver transplantation, US contrast allows a comprehensive assessment of hepatic artery thrombosis, hepatic artery stenosis and pseudoaneurysm formation. The need for further imaging is reduced or confidently deferred in many instances. Ultrasound contrast agents play an important role in the liver transplant candidate. Received: 15 April 1999; Revised: 21 June 1999; Accepted: 22 June 1999     

Congenital and acquired anomalies of the portal venous system.

Knowledge of the normal anatomy, most frequent variants, and congenital and acquired anomalies of the portal venous system is of great importance for liver surgery and interventional procedures such as creation of transjugular intrahepatic portosystemic shunts. Radiologic studies of the portal venous system include color Doppler ultrasonography (US), computed tomography (CT), magnetic resonance imaging, and arterial or direct portography. Among the most common branching variants of the portal vein are trifurcation, right anterior portal branch arising from the left portal vein, and right posterior portal branch arising from the main portal vein. Agenesis of the right or left portal vein is the most frequently reported congenital anomaly. Venous collateral vessels due to portal hypertension and cavernous transformation of the portal vein are best evaluated with cross-sectional imaging. Intrahepatic portosystemic, arterioportal, and arteriosystemic fistulas and associated perfusion anomalies have characteristic features at dual-phase helical CT. Color Doppler US is the single most useful tool for demonstration of aneurysms of the portal venous system and bland or neoplastic portal vein thrombosis. CT is also the best means of evaluating gas in the portal venous system, which is no longer an ominous sign and must be differentiated from aerobilia.     

Recent variceal bleeding: Doppler US hepatic vein waveform in assessment of severity of portal hypertension and vasoactive drug response

PURPOSE: To prospectively evaluate both the correlation between abnormal Doppler ultrasonography (US) hepatic vein waveforms and the hepatic venous pressure gradient (HVPG) and the response to drug treatment in patients with cirrhosis. MATERIALS AND METHODS: Ethics committee approval and informed consent of patients and control subjects were obtained. In 78 patients with cirrhosis (70 men, eight women; mean age, 49.4 years +/- 9.7 [standard deviation]) and a history of variceal bleeding, both the hepatic vein waveform--as measured with Doppler US--and the HVPG were measured, and the relationship between them was analyzed. Hepatic vein Doppler waveforms were classified as triphasic, biphasic, or monophasic. Severe portal hypertension was defined as an HVPG of more than 15 mm Hg. In a subgroup of 21 patients, changes in hepatic vein waveform and HVPG were evaluated after intravenous administration of 2 mg of terlipressin. Statistical analyses were performed with Spearman rank correlation, logistic regression analysis, and cross tabulation. RESULTS: Abnormal hepatic vein waveforms were seen in 72 patients (92%). Forty-four patients (56%) had biphasic waveforms, 28 (36%) had monophasic waveforms, and six (8%) had triphasic waveforms. A positive correlation was found between the extent of abnormalities in hepatic vein waveforms and the increase in HVPG (P < .05). Monophasic waveforms were associated with severe portal hypertension, with a sensitivity of 74% and a specificity of 95%. Twenty patients in the terlipressin subgroup had abnormal baseline waveforms; the baseline waveform improved in 18 patients in association with the HVPG reduction after injection of terlipressin. CONCLUSION: Doppler US hepatic vein waveform assessment is useful in the noninvasive evaluation of the severity of portal hypertension and the response to vasoactive drugs in patients with portal hypertension and variceal bleeding.     

Evaluation of hepatic venous pulsatility and portal venous velocity with Doppler ultrasonography during the puerperium.

OBJECTIVE: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. METHODS AND MATERIAL: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. RESULTS: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. CONCLUSION: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period.     

Doppler sonographic abnormalities suggestive of venous congestion in the right lobe graft of living donor liver transplant recipients

OBJECTIVE: Establishing optimal hepatic venous outflow is the key for a successful outcome of living donor liver transplantation using a right lobe graft. The purpose of this article is to illustrate the surgical techniques of middle hepatic vein reconstruction with an interposition vein graft in living donor liver transplant recipients using a modified right lobe graft, normal postoperative Doppler sonographic findings, and various Doppler sonographic abnormalities suggestive of hepatic venous congestion. CONCLUSION: Hepatic venous congestion after living donor liver transplantation using a right lobe graft may produce various abnormalities on Doppler sonography. In addition to allowing the patency of the middle hepatic vein tributaries and interposition vein graft to be assessed during the early postoperative period, Doppler sonography can depict the flow direction in the portal vein and in the middle hepatic vein tributaries; therefore, Doppler sonography can reveal reversal of portal flow direction in patients with acute and severe venous congestion and can show the presence of a functional intrahepatic anastomosis between the hepatic vein tributaries during the follow-up period in those with improved congestion.     

Successful embolization of a congenital intra-hepatic arterioportal fistula in a neonate with the MVP Microvascular Plug system (MVP-3Q)

This case report describes a neonate with an antenatally diagnosed vascular anomaly of the liver. Ultrasound at birth confirmed an arterioportal fistula communicating the left hepatic artery and an anterior branch of the right portal vein. Computer tomography angiography on day 7 of life redemonstrated the arterioportal fistula and defined the vascular anatomy for potential treatment. Transarterial embolization of the arterioportal fistula was performed at 3 weeks of life using an MVP Microvascular Plug System 3Q (Reverse Medical Corp, Irvine, CA, USA). Intra-procedural angiography showed successful occlusion of the fistula, patency of the portal vein with hepatopetal flow, and patency of the hepatic artery with no signs of arterial or venous thrombosis. There were no intra- or post-procedure complications. Multiple follow-up ultrasounds at 1-13 months showed stable occlusion of the embolized fistula with no evidence of recanalization, with the patient having a normal life and no sequelae. This case illustrates a successful novel approach to manage the rare condition of a solitary hepatic arterioportal fistula in a neonate using the MVP system. Current literature on congenital arterioportal fistulas and the MVP system is reviewed.     

Hemodynamic significance of the paraumbilical vein in portal hypertension: assessment with duplex US

Hemodynamic evaluation of portal and umbilical venous flow with duplex ultrasound (US) was performed in 11 patients with cirrhosis of the liver and a large umbilical vein. Two of these patients had hepatofugal flow in the umbilical vein exceeding hepatopetal flow in the portal vein. These two patients had no evidence of esophageal varices and bleeding. The remaining nine patients had esophageal varices. In these patients, the hepatopetal flow in the portal vein exceeded the hepatofugal flow through the umbilical vein. The authors conclude that duplex US may help identify the massive hepatofugal flow through a large umbilical vein that may reduce the likelihood of esophageal varices and variceal bleeding.