CT仿真内窥镜技术在肝门静脉变异分析中的应用

目的探讨CT仿真内窥镜(CTvirtual endoscopy,CTVE)在精确区分肝门静脉变异类型中的应用价值。方法对CT门静脉血管成像(CTportal angiology,CTPA)病例中筛选出MIP、VR显示为肝门静脉主干3分叉的15例病人和右支主干显示为3分叉的17例病人用CTVE分析。重点分析3分叉处的管腔结构,例如肝门静脉主干处,右前支-左支(RAPV-LPV)短共干或者是右前支-右后支(RAPV-RPPV)短共干很容易被误认为主干3分叉。以评价CTVE在分辨短共干与3分叉中的价值,纠正原始方法观察分支的欠缺。结果肝门静脉主干3分叉中60%(9例)经CTVE分析为短RAPV-LPV共干或短RAPV-RPPV共干。17例右支主干3分叉中,35%(6例)为右支主干先分出右后上支,然后分为右后下支和右前支,12%(2例)例为正常解剖(I型变异)。经CTVE分析后,32例病人只有47%(15例)是真正3分叉,阳性率仅为0.47,统计学有显著差异。结论由于短共干分支外观上极易与真正3分叉混淆,而CTVE可以真实显示腔内分叉的顺序,从而清晰鉴别3分叉与短共干。此方法可用于肝门静脉解剖的研究,纠正原始方法的不足,获得更加准确的数据。     

Reflex renal vasoconstriction on portal vein distension

The present experiments were designed to study effects of neural control mechanisms on renal sympathetic nerve activity during acute portal vein distension in anesthetized dogs. Following the inflation of a balloon placed into the main portal vein of animals with the neuraxis intact (intact group), portal vein pressure at a site of the splanchnic regions increased significantly. Mean blood pressure (MBP) fell significantly and then renal vascular resistance (RVR) increased significantly in parallel with changes in portal venous pressure. In animals with sinoaortic denervation (SAD group), changes in portal venous pressure during the inflation of a balloon did not differ from the intact group. However, decreases in MBP in the SAD group were greater than that in the intact group, and sinoaortic denervation did not alter increases in RVR. In animals with both sinoaortic denervation and cervical vagotomy (vagotomy group), portal vein distension produced more profound hypotension, and significant increases in RVR occurred. This increase in RVR, however, was abolished by renal nerve denervation. The results of the present study indicate that increases in RVR during the portal vein distension, which is associated with systemic hypotension, may be mediated by an activation of efferent sympathetic renal nerves and modified by at least two neural reflex mechanisms such as carotid sinus baroreceptors and cardiopulmonary baroreceptors. In addition, local reflex systems such as stretch receptors in the venous wall of the portal vein may be involved in excitatory response to renal sympathetic nerve, leading to renal vasoconstriction, during the portal vein distension.     

Absence of bifurcation of the portal vein

Background  Absence of the horizontal segment of the left portal vein (PV) or absence of bifurcation of the portal vein (ABPV) is extremely rare anomaly. The aim of this study was to study the extra-hepatic PV demonstrating the importance of its careful assessment for the purpose of split-liver transplantation. Method  Human cadaver livers (n = 60) were obtained from routine autopsies. The cutting plane of the liver consisted of a longitudinal section made immediately on the left of the supra-hepatic inferior vena cava through the gallbladder bed preserving the arterial, portal and biliary branches in order to obtain two viable grafts (right lobe—segments V, VI, VII, and VIII and left lobe—segments II, III, and IV) as defined by the main portal scissure. The PV was dissected out and recorded for application of the liver splitting. Results  The PV trunk has been divided into right and left branch in 50 (83.3%) cases. A trifurcation of the PV was found in 9 (15.2%) cases, 3 (5%) was a right anterior segmental PV arising from the left PV and 6 (10%) a right posterior segmental PV arising from the main PV. ABPV occurred in 1 (1.6%) case. Conclusion  Absence of bifurcation of the portal vein is a rare anatomic variation, the surgeon must be cautious and aware of the existence of this exceptional PV anomaly either pre or intra-operatively for the purpose of hepatectomies or even split-liver transplantation.     

Direct effects of various catecholamines on liver circulation in dogs.

As measured by electromagnetic blood flow transducers, direct infusion of epinephrine, norepinephrine, and dopamine into the portal vein (PV) produced a 40-50% decrease in hepatic arterial (HA) blood flow; isoproterenol increased HA flow by about 69%. No changes in PV flow or pressure were observed. Direct HA infusion of the vasoconstrictors decreased HA flow by amounts comparable to those occurring after PV infusion. However, HA infusion of isoproterenol increased HA flow only 15% suggesting a difference in beta-receptor population in the two vessels. When infused directly into the superior mesenteric artery (SMA), epinephrine and norepinephrine reduced SMA flow by about 45% and PV flow by 20-25%; HA flow increased 6-8%. Infusion of isoproterenol and dopamine into SMA increased SMA flow by 115% and 206% and PV flow by 60% and 70%, respectively, whereas HA flow decreased by 25% and 50%. Portal vein pressure increased less than 3 mmHg. Alpha- and beta-receptor blockade of the liver did not change significantly the alterations in hepatic arterial blood flow that were secondary to changes in portal venous blood flow. It is likely that regulation of hepatic arterial flow resides in mechanisms located within the liver sinusoids.     

Some aspects of the portal circulation in the liver in shock

Summary A study was made of the circulation in the portal vein of cats during shock resulting from current. To assess the circulation the author measured the blood pressure in the portal and posterior vena cavas, estimated the portocaval gradient and took repeated roentgenograms of the portal vein with the cardiotrast contrasting thereof. As revealed, the pressure in the portal vein and in the portocaval gradients was rather high even at the late phases of shock, when the arterial pressure had already undergone a considerable drop. This may be attributed to a marked resistance to the blood flow in the intrahepatic portion of the portal circulation, which is confirmed by the roentgeno grams.(Presented by Active Member AMN SSSR A. V. Lebedinskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 54, No. 10, pp. 51–54, October, 1962     

肝硬变门脉高压症大鼠舌脉的血流动力学变化及其发生机制的研究

用小剂量ＣＣＩ＿４皮下注射与脂肪饲料及乙醇喂饲复制肝硬变门脉高压性瘀证大鼠模型，以探索中医舌脉变化与舌深静脉压、门脉压、门脉血流量之间的关系。实验结果表明，实验组大鼠均已形成肝硬变，并以假小叶形成的三期病变为主，肝窦不清晰，间隙变窄乃至闭塞；舌腹面粘膜下乃至肌间、食管及胃肠粘膜下均有微小血管淤血，脾脏淤血更为明显；舌深静脉压力升高，与门脉压升高呈正相关；门脉血流量明显减少，与正常对照组大鼠比较Ｐ＜０．０１．认为肝硬变门脉高压性瘀症的舌脉粗张与细络瘀血主要是因门脉血经门一腔侧支循环回流入上腔静脉，引起上腔静脉阻力增大，压力增高，导致舌的静脉系统回流受阻，使舌深静脉血流量增多，压力升高所致。     

门静脉部分缩窄制作SD大鼠门静脉海绵样变性动物模型

目的采用门静脉部分缩窄法建立SD大鼠门静脉海绵样变性(CTPV)的动物模型,观察成模过程中门静脉压力、门静脉及周围组织的结构变化,为临床及基础研究提供可靠、稳定的模型动物。方法将SD大鼠100只,随机分为2组:假手术组和模型组,每组各50只。模型组用21G口径的钝头针对大鼠门静脉部分缩窄术;假手术组仅对门静脉进行游离探查,不进行缩窄。各组分别在术后1、2、3、4、6w随机取出10只,行门静脉测压、门静脉造影、病理学等观察门静脉及其周围组织侧支循环的形成情况。结果假手术组大鼠术后各时间段均未形成门脉高压,门静脉造影未见有侧支循环形成。模型组术后1w即形成门静脉高压,门静脉造影显示术后第3w,肝门区可见向肝性侧支循环,术后6w,门静脉区形成典型的海绵样变性。结论用21G钝针头行门静脉部分缩窄,可以复制出类似CTPV的大鼠模型。术后3w门静脉压力达到高峰,以后稍有下降并逐渐趋于稳定,在术后3w门静脉已出现向肝性侧支循环,到6w时形成典型的门静脉海绵样变性改变。     

The hepatic arterial blood flow response to portal vein occlusion in the dog

The acute effect of portal vein occlusion on hepatic arterial blood flow was studied in a group of nine anaesthetised dogs. The influence of hepatic artery denervation and total liver denervation on the hepatic arterial flow response was determined subsequently. Blood flows in the hepatic artery and portal vein were measured with electromagnetic flowmeters, and hepatic tissue perfusion with⁸⁵Krypton clearance. A side-to-side mesocaval shunt was constructed to provide a drainage channel for the mesenteric venous blood during the periods of portal vein occlusion.Occlusion of the portal vein produced an immediate and significant increase in hepatic arterial flow which was sustained at approximately 80% above control for the 6 min period of observation. Total liver blood flow and hepatic tissue perfusion were both significantly reduced by about 40%. Denervation either of the hepatic artery alone or the entire liver produced no change in the response, and it is concluded that there is no neurogenic component either initiating or modifying the early changes in hepatic arterial flow.     

Hepatic arterial perfusion regulates portal venous flow between hepatic sinusoids and intrahepatic shunts in the normal rat liver in vitro

Intrahepatic shunts regulate portal venous pressure during periods of acute portal hypertension when the transhepatic portal resistance is momentarily increased in the normal rat liver in vivo. Hepatic arterial inflow may also increase the transhepatic portal resistance and activate intrahepatic shunts. In the present study, the transhepatic portal resistance and the activity of intra-hepatic shunts were measured in vitro and the point of confluence between the hepatic artery and portal vein in the rat determined. Livers of male Sprague-Dawley rats were single-pass, dual-perfused in vitro. Total cessation or diversion of the hepatic arterial inflow to the portal venous vasculature, whilst maintaining total hepatic perfusate flow, decreased intrasinusoidal pressure, increased transhepatic portal venous resistance and opened the portal venous intrahepatic shunts in a manner similar to intraportal injection of 15-microm diameter microspheres. Injections of the microspheres into the hepatic arterial circulation increased hepatic arterial pressure dramatically, consistent with complete occlusion of the arterial vasculature. The intrahepatic shunts are located at a pre-sinusoidal level because no increases were detected in hepatic arterial pressure following intraportal injection of microspheres. The hepatic arterial vasculature, unlike the portal supply, does not possess a collateral shunt circulation and coalesces with the portal vein at an intrasinusoidal location     

A simplified method for chronic portal vein cannulation in the rat

A simple technique is described for chronic cannulation and repeated blood sampling from the portal vein of the conscious undisturbed rat. The method employs a straight cannula and allows precise location of the tip. Blood flow in the portal vein is not obstructed. The present technique was used in combination with chronic cannulation of the superior vena cava. Simultaneous blood sampling from the two cannulas was successfully carried out at fifteen minute intervals over six hour periods. The system and the sampling were well tolerated by the rats.     

Cryptic Met-enkephalin in adrenal and portal vein during splanchnic artery occlusion shock in cats

Adrenal vein (AD), portal vein (PV), and femoral artery (FA) plasma levels of immunoreactive (IR) Met-enkephalin pentapeptide (ME) and extended ME-IR forms, obtained after sequential incubation of plasma with trypsin and carboxypeptidase B, were examined in 4 cats during splanchnic artery occlusion shock at baseline (S1), during early shock (S2), late shock (S3), and after naloxone (1 mg/kg, i.v.) administration (S4). Early shock (S2) led to a significant increase in levels of extended and fully processed Met-enkephalin IR at all 3 collection sites (AD, PV, FA) without a change in proportional levels of extended Met-enkephalin IR to the pentapeptide IR (ME). Naloxone administration during late shock (S4), however, resulted in a disproportionate increase (150-fold from baseline) in adrenal vein plasma levels of extended Met-enkephalin IR forms, as compared to ME IR (23-fold). In contrast, no changes in plasma levels occurred in PV and FA.     

Flow competition between hepatic arterial and portal venous flow during hypothermic machine perfusion preservation of porcine livers

Hypothermic machine perfusion (HMP) is regarded as a better preservation method for donor livers than cold storage. During HMP, livers are perfused through the inlet blood vessels, namely the hepatic artery (HA) and the portal vein (PV). In previous HMP feasibility studies of porcine and human livers, we observed that the PV flow decreased while the HA flow increased. This flow competition restored either spontaneously or by lowering the HA pressure (PHA). Since this phenomenon had never been observed before and because it affects the HMP stability, it is essential to gain more insight into the determinants of flow competition. To this end, we investigated the influence of the HMP boundary conditions on liver flows during controlled experiments. This paper presents the flow effects induced by increasing PHA and by obstructing the outlet blood vessel, which is the vena cava inferior (VCI). Flow competition was evoked by increasing PHA to 55-70 mmHg, as well as by obstructing the VCI. Remarkably, a severe obstruction resulted in a repetitive and alternating tradeoff between the HA and PV flows. These phenomena could be related to intra-sinusoidal pressure alterations. Consequently, a higher PHA is most likely transmitted to the sinusoidal level. This increased sinusoidal pressure reduces the pressure drop between the PV and the sinusoids, leading to a decreased PV perfusion. Flow competition has not been encountered or evoked under physiological conditions and should be taken into account for the design of liver HMP protocols. Nevertheless, more research is necessary to determine the optimal parameters for stable HMP.     

16层螺旋CT上正常人肝内门静脉变异分析

目的:应用16层螺旋CT肝内门静脉成像技术分析正常人肝内门静脉主干分支的变异。方法:采用test-bolus技术测定正常人主动脉、门静脉及肝实质强化峰值时间;再经肘静脉注射大剂量造影剂,于该门脉峰值时间开始扫描全肝脏。采用厚层MIP(maximum intensity projection)观察门静脉1~3级分支情况,并结合SSD(shaded surface display,SSD)及VRT(volume rendering technology)确定门静脉分支情况。结果:本组正常人肝内门静脉一级分支共有7种变异类型,变异率高达33.3%,高于以往研究。结论:正常人肝内门静脉变异率较高,因此肝脏术前进行肝内门静脉成像及其分支的评估非常必要。     

“肝脏反馈机制”并非门脉高压症高动力循环的发生机制

观察“肝脏反馈机制”在门脉高压症（ＰＨＴ）内脏高动力循环发生过程中的作用，检测了门静脉分支结扎（ＰＢＬ）大鼠和门静脉缩窄肝前型ＰＨＴ（ＰＶＬ）大鼠不同时期的血流动力学变化。结果显示：ＰＢＬ术后７天由于门静脉阻力增加，门静脉压力出现一过性增高，第５，７天出现类似于ＰＶＬ大鼠的短暂的全身高动力循环状态，整个实验过程中，尽管ＰＢＬ大鼠部分肝脏失去了门静脉血供，但未发现象ＰＶＬ大鼠所表现的内脏血管阻力下降     

Blood flow distribution in the renal portal system of the intact hen. A study of a venous system using microspheres

The blood flow in the renal portal system of intact hens was characterized by determining the fractional distribution of 15 μm and 50 μm microspheres in this system after injection into a leg vein. Validation tests showed that only 50 μm spheres gave a reliable estimation of this distribution. The blood flow in the coccy-geomesenteric vein was directed towards the liver in nearly all cases. On the average 44, 47 and 8% of the portal blood from the external iliac vein perfused the ipsilateral kidney, the liver and the lungs, respectively. However, the distribution of portal blood to these organs varied considerably between individuals and changed appreciably within 35 min in half the animals studied. The reason for these variations is not clear. The portal blood from the right and left external iliac veins was asymmetrically distributed in most animals illustrating the importance of local factors in its regulation. Variation was great in the regional distribution of portal blood within the kidney possibly due to local vasoconstriction of portal vessels. Further information e.g. on the regulation of renal portal blood flow is needed to explain its physiological significance. Microspheres provide a convenient method for such studies. A combination of microsphere and Sperber techniques allows us to determine the renal excretion efficiency of a given substance.     

Blood glucose levels in portal and peripheral circulation and their relation to food intake in the rat

Rats weighing about 450 g were provided with permanent catheters in the portal vein and the right auricle. This method allows blood sampling from the portal and peripheral circulation at the same moment in the nondisturbed unanesthetized rat. In the ad lib condition the portal glucose level was higher than that in the general circulation before, during, and after the meal. After a fast of 22 hr premeal portal vein levels were equal to those of the general circulation. During the meal the portal glucose levels rose to about 150 mg per 100 ml whereas those of the general circulation did not exceed 130 mg/100 ml. Experiments with glucose infusions systemically and intraportally show that, under conditions of mild deprivation, the level of glucose in the portal vein plays no or only a very minor role in the termination of feeding.     

当归对正常及肝硬化犬血浆胰高血糖素水平的影响

众所周知，胰高血糖素参与了肝硬化高动力循环和门脉高压的形成。我们以往的研究证实。中药当归对肝硬化门脉高压症有良好的预防及治疗作用。为探讨其作用机理，本文研究了当归对正常及胆道结扎肝硬化犬内脏血浆胰高血糖素水平的影响。结果表明，用药后两组动物血浆胰高血糖素水平均显著下降，且肝硬化组下腔静脉和门静脉内血浆胰高血糖素水平的变化与其门脉和门脉血流量的变化呈显著正相关。提示当归可能通过减少胰高血糖素的分泌和     

Meal induced changes in hepatic and splanchnic circulation: a noninvasive Doppler study in normal humans

Summary The haemodynamic effects of a meal on the splanchnic and hepatic circulation were evaluated in 30 healthy volunteers, using Doppler ultrasonography. The resistance index (RI) of the superior mesenteric artery and of the left and right intrahepatic arteries, the portal vein blood flow as well as the ratio between maximal velocity in the left and right intrahepatic arteries and the adjacent portal vein were measured initially, then 15, 30, 45, and 60 min after the ingestion of a standard balanced liquid meal. Postprandial haemodynamic changes were maximal 30 min after the meal; at that time, mesenteric artery RI decreased significantly [mean –11% (SEM 14%)] whereas portal vein blood flow increased markedly [mean +79% (SEM 14%)]; a significant increase in hepatic artery RI was observed in both liver lobes. The ratio between maximal velocities of the intrahepatic artery and the intrahepatic portal vein was reduced significantly; this ratio decreased more markedly in the right lobe of the liver. These findings would suggest that there was an adaptation of hepatic artery to portal vein blood flow after a meal. The subsequent increase in intrahepatic portal vein flow velocity was found to be greater in the right lobe of the liver.     

Prehepatic portal hypertension worsens the enterohepatic redox balance in thioacetamide-cirrhotic rats

Background: Oxidative stress has been reported as a key pathogenic factor in many human liver diseases and in experimental models of cirrhosis related to hepatotoxin administration. The aim of this study was to verify the hypothesis that prehepatic portal hypertension aggravates the enterohepatic redox imbalance in thioacetamide-cirrhotic rats. Materials and methods: Wistar male rats were used: Control (n = 9); rats with prehepatic portal hypertension by triple partial portal vein ligation (TPVL; n = 9); thioacetamide-cirrhotic rats (TAA; n = 9) and TPVL-rats associated to TAA administration (TPVL + TAA; n = 9). Three months after the operation, portal pressure (PP), mesenteric venous vasculopathy (MVV) and portosystemic collateral circulation were studied. Liver and ileal levels of malondialdehyde (MDA), as a lipid peroxidation marker, and catalase (CAT), glutathione peroxidase (GSH-Px), glutathione transferase (GSH-t) and cytosolic and mitochondrial superoxide dismutases (cSOD and mSOD), as antioxidative enzymatic mechanisms, were measured. Results: Liver and ileal MDA increased in all the experimental groups, although the higher increase occurred in the ileum of rats with portal hypertension. CAT levels decreased in the liver and the ileum in the three experimental groups. The decrease in liver and ileal GSH-Px and GSH-t was greater in rats with portal hypertension, alone or associated with TAA. mSOD activation was demonstrated in the liver when portal hypertension was added to TAA. On the contrary, this compensatory response was not activated in the ileum, where mSOD was significantly decreased. Conclusion: Prehepatic portal hypertension by triple partial portal vein ligation impaired the enterohepatic antioxidative activity and aggravated the intestinal oxidative stress in thioacetamide-cirrhotic rats.     

一种新的大鼠门静脉动脉化模型

背景：目前文献报道的大鼠门静脉动脉化模型有缝合法或支架法,2种方法在血管通畅率及操作便利性上均不太理想。 目的：建立稳定的操作简便的大鼠门静脉动脉化动物模型。 方法：采用同种异体血管套入式缝合及袖套法建立大鼠门静脉动脉化模型40例。切除左肾,将左肾动脉与门静脉残端通过同种异体血管连接,左肾静脉借助袖套与肠系膜上静脉连接。另取10只大鼠作为假手术组。术后观察大鼠的体质量变化和存活情况,2周行磁共振血管成像,1个月检测大鼠肝功能,2个月处死大鼠探查门静脉血流通畅情况并观察肝脏的病理学改变。 结果与结论：造模过程中有1只大鼠死亡,其余39只均存活至术后2个月,造模成功率为98%(39/40)。术后1个月,模型组与假手术组大鼠体质量,血清白蛋白、谷丙转氨酶、碱性磷酸酶和胆碱酯酶差异均无显著性意义(P > 0.05)。术后2个月,模型组门静脉通畅率为95%(37/39)。磁共振血管成像及病理结果均未见明显异常。提示,利用同种异体血管套入式缝合及袖套法建立的大鼠门静脉动脉化模型操作简便、省时、成功率高,是一种可行、稳定、可靠、可重复性强的方法。