肝门静脉高压症猪肝门静脉的结构重建

目的:建立猪肝门静脉高压症模型,探讨肝门静脉高压症时肝门静脉的结构重建.方法:猪以四氯化碳、苯巴比妥、乙醇配合高脂、低蛋白、低胆碱饮食进行混合饲养.通过脾静脉插管测压,取门静脉常规石蜡包埋、切片,用H-E 染色法、Weigert法、Aniline blue法、Organge G法分别染组织结构、弹性纤维、胶原纤维和平滑肌,用计算机图像分析系统定量分析肝门静脉的几何形态及显微成分.结果:实验组肝门静脉压为(4.17±1.03)kPa,而正常组为(1.51±0.79)kPa,实验组门静脉的内膜与中膜增厚,管壁增厚,管径增粗,平滑肌、胶原纤维的百分含量增加,平滑肌细胞核的数密度和面密度也在增加,C/E值增加.结论:肝门静脉高压症时,与血液动力学改变相适应,肝门静脉的几何形态与显微结构成分均发生了改变.     

Microvasculature in the small portal tracts in idiopathic portal hypertension

Summary The morphology of the microvasculature in the small portal tracts was examined in normal livers, idiopathic portal hypertension (IPH) and other hepatic diseases. The microvasculature examined was arbitrary divided into two groups: that near the limiting plate and that within portal tracts, particularly around bile ducts. Based on comparisons of histology, immunohistochemistry and vascular casts, it is suggested that the former corresponded to inlet venules and the latter to distributing portal veins and peribiliary capillary plexus. Both of these microvasculatures were positive forUlex europaeus lectin I, and (infrequently and weakly) for factor VIII-related antigen. Morphometry disclosed that inlet venules were reduced in number in IPH compared with normal livers and that distributing portal veins, peribiliary capillary plexus and inlet venules were increased in extrahepatic portal obstruction, chronic active hepatitis and extrahepatic obstructive cholestasis. We believe that the change in the microvasculature reflects abnormal microcirculation in the small portal tracts, and that the reduction of inlet venules plays an important role in the development of portal hypertension in IPH.     

HLA-DR expression on the microvasculature of portal tracts in idiopathic portal hypertension. Immunohistochemical characteristics and relation to portal phlebosclerosis

We recently reported that HLA-DR antigen was expressed on the microvasculature of portal tracts more frequently in idiopathic portal hypertension (IPH) than in normal livers or in other hepatic diseases, and that this HLA-DR expression may be involved in the development of the portal venopathy characteristic of IPH. The present study was performed to evaluate the relationship between the HLA-DR expression and portal tract lesions, as well as to investigate the immunohistochemical characteristics of the HLA-DR-positive microvasculature using liver wedge biopsy specimens obtained from 32 patients with IPH. According to the degree of phlebosclerosis of the portal veins, the portal tracts were divided into three groups: mild, moderate, and severe. The microvasculature in portal tracts was positive for HLA-DR in 21 (66%) of the 32 specimens and in 133 (44%) of 302 portal tracts. In the 21 specimens, there was no significant difference in the prevalence of HLA-DR-positive microvasculature among the three groups: it occurred in 57 (66%) of 86 portal tracts in the mild group, 53 (61%) of 87 portal tracts in the moderate group, and 23 (49%) of 47 portal tracts in the severe group. The HLA-DR-positive microvasculature was positive for type IV collagen and receptors of Ulex europaeus lectin I, suggesting that HLA-DR-positive microvessels are blood vessels. These findings suggest that HLA-DR antigen is already expressed on portal microvessels in the incipient stage of IPH, and that HLA-DR expression persists during the progression of portal phlebosclerosis. The HLA-DR expression may be an initiating factor leading to immunologic assault on portal microvessels in IPH.     

Metoprolol in portal hypertension

Summary In a controlled trial, the effect of the ₁-selective blocking agent metoprolol on cirrhotic portal hypertension was investigated. A sustained reduction of portal pressure was observed in 60% of the treated patients after 1 and 2 months. No correlation between changes of portal pressure and cardiac output was established. This may indicate a direct action of-blocking substances on the splanchnic vascular system. The results suggest that treatment with metoprolol may be of value in patients with portal hypertension secondary to cirrhosis of the liver. However, to eliminate nonresponders the pressure has to be measured repeatedly.     

Idiopathic noncirrhotic portal hypertension

Cirrhosis is the most common cause of portal hypertension but there are many causes of noncirrhotic portal hypertension. Many of these etiologies may be diagnosed by liver biopsy. Idiopathic noncirrhotic portal hypertension is being increasingly diagnosed and has varied histopathological findings as well as overlapping definitions. Many of these histological changes can be subtle, thus making it a challenging diagnosis for the pathologist to make. This review summarizes the clinical aspects of idiopathic noncirrhotic portal hypertension and outlines the different definitions and histological features of the entity. In addition, pearls and pitfalls for the pathologist in making this diagnosis are included.     

Blood flow in mesenteric,hepatic portal and renal portal veins of chickens

Blood flows were determined by electromagnetic probes placed upon the posterior vena cava (PVC), coccygeomesenteric vein (COCMV), mesenteric vein (MV), and hepatic portal vein (PV) of white Leghorn males. Blood flow in ml/min of non-fasted, unanesthetized males were as follows: (see article). Withholding food for 24 hrs decreased flow significantly only in the MV and PVC. Anesthesia decreased flow in PVC, PV and COCMV. After ligation of PVC, blood was shunted from caudal areas and renal portal circulation to COCMV and liver. Ligation of PV caused a diversion of flow to renal portal circulation and an increase in PVC flow and a reversal of direction of flow in COCMV.     

Collateral pathways in portal hypertension

Summary In a retrospective study angiographic image material of percutaneous direct portographies carried out in 43 patients was evaluated according to anatomic and radiologic criteria. These examinations were performed for therapeutic purposes (embolisation of vessels supplying varices). All the hepatofugally perfused veins were analyzed according to their localisation and course. Apart from the known portocaval collateral pathways a number of other collaterals not yet described could be documented by means of angiography.

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Les voies de dérivation veineuse dans l'hypertension portale

Résumé A partir de l'analyse rétrospective de portographies directes effectuées par angiographie percutanée chez 43 patients, différents critères anatomiques et radiologiques ont été précisés. Ces portographies ont été faites dans un but thérapeutique (embolisation des vaisseaux alimentant des varices sophagiennes); la localisation et le trajet de toutes les veines hépatofuges ont été étudiés. A côté de la circulation collatérale porto-cave connue, il existe un certain nombre d'autres voies de dérivation actuellement incomplètement décrites et qui peuvent être précisées par angiographie.

     

Diaphragmatic sulci and portal fissures

Diaphragmatic sulci in the superior surface of the liver were found in 40% of cases at autopsy. All sulci were located in the right lobe and in 47% they were multiple. In order to evaluate possible predisposing factors for these accessory sulci, their topography and characteristics were observed in unfixed livers; moreover, intravenous injections of radio‐opaque resins were performed in the portal and hepatic veins (HVs). After formalin fixation, the livers underwent CT and MR scans and a three‐dimensional (3D) elaboration of the images was performed. Radiological examination revealed a correspondence between the topography of the sulci and the course of the right and middle HVs and their main tributaries in 67%. The corrosion casts showed the location of the sulci at the level of the boundaries between the ramifications of the terminal branches of the portal triad, where the HVs are located, in 73%. These findings suggest that, rather than the action of ‘special’ or hypertrophied muscle bundles, the pressure exerted by the diaphragm as a whole may be responsible for the production of sulci at the level of weak zones, represented by the portal fissures, where the watershed superficial hepatic parenchyma, owing to the absence of all but the smallest vascular branches, exhibits a lower resistance to external pressure.     

Investigation of tilted dose kernels for portal dose prediction in a-Si electronic portal imagers

The effect of beam divergence on dose calculation via Monte Carlo generated dose kernels was investigated in an amorphous silicon electronic portal imaging device (EPID). The flat-panel detector was simulated in EGSnrc with an additional 3.0 cm water buildup. The model included details of the detector's imaging cassette and the front cover upstream of it. To approximate the effect of the EPID's rear housing, a 2.1 cm air gap and 1.0 cm water slab were introduced into the simulation as equivalent backscatter material. Dose kernels were generated with an incident pencil beam of monoenergetic photons of energy 0.1, 2, 6, and 18 MeV. The orientation of the incident pencil beam was varied from 0 degrees to 14 degrees in 2 degrees increments. Dose was scored in the phosphor layer of the detector in both cylindrical (at 0 degrees) and Cartesian (at 0 degrees - 14 micro) geometries. To reduce statistical fluctuations in the Cartesian geometry simulations at large radial distances from the incident pencil beam, the voxels were first averaged bilaterally about the pencil beam and then combined into concentric square rings of voxels. Profiles of the EPID dose kernels displayed increasing asymmetry with increasing angle and energy. A comparison of the superposition (tilted kernels) and convolution (parallel kernels) dose calculation methods via the chi-comparison test (a derivative of the gamma-evaluation) in worst-case-scenario geometries demonstrated an agreement between the two methods within 0.0784 cm (one pixel width) distance-to-agreement and up to a 1.8% dose difference. More clinically typical field sizes and source-to-detector distances were also tested, yielding at most a 1.0% dose difference and the same distance-to-agreement. Therefore, the assumption of parallel dose kernels has less than a 1.8% dosimetric effect in extreme cases and less than a 1.0% dosimetric effect in most clinically relevant situations and should be suitable for most clinical dosimetric applications. The resulting time difference for the parallel kernel assumption versus the tilted kernels was 10.5 s vs 18 h (a factor of approximately 6000), dependent on existing hardware and software details.     

门静脉高压症猪门静脉的生物力学特性及其临床意义

目的:建立猪门静脉高压症模型,探讨门静脉高压症时门静脉的生物力学特性。方法:采用2月龄湖北白种猪,用四氯化碳、苯巴比妥、乙醇,配合高脂、低蛋白、低胆碱饮食进行混合饲养。通过脾静脉插管测压,取门静脉在生物软组织力学试验机上测定其压力-直径关系,横断取材,冰冻切片,H E法染色,用计算机图像分析系统测量其几何形态学指标。结果:实验组门静脉压为(4.17±1.03)kPa,对照组为(1.51±0.79)kPa(P<0.01),实验组门静脉的Einc、Ep和EV均随压力的上升而增大,在相同压力下明显大于对照组的Einc、Ep和EV。在0～4 kPa压力范围内实验组门静脉的顺应性(C)显著低于对照组,而在4～8 kPa的高压时两者顺应性差异并不明显(P>0.05)。结论:门静脉高压症时,门静脉的生物力学特性均发生了明显变化。肝移植时,移植材料间的生物力学特性也应考虑。     

Hepatic grooves and portal segmentation

The aim of the present study was to examine the topographical relationship between the locations of the grooves and the borders of Couinaud's portal segments. We found 79 grooves on the diaphragmatic surfaces of 50 livers from 420 cadavers. Most grooves were located within segment VIII wholly (31/79) or partially (39/79). By contrast, only 11 grooves corresponded to the border between two segments (segments VIII/IV in 6 cases and segments VIII/VII in 5 cases). Diaphragmatic indentations (fold-like protrusions) into the groove were observed in 1 case. Our results suggest that the grooves did not form during the early embryonic period when intrahepatic vessels and ducts ramify, but that they formed during a later stage of diaphragmatic growth after establishment of the basic segmental configuration of the liver. The grooves do not seem to be critical landmarks for segmental borders of the liver.     

门静脉癌栓与门静脉血栓的多层螺旋CT影像研究

目的 探讨肝硬化合并肝癌、门静脉癌栓患者和肝硬化合并门静脉血栓患者的癌栓与血栓的MSCT影像特点及病变解剖部位的差异。方法 回顾性分析2011年5月—2016年5月北京大学深圳医院和2013年8月—2014年8月广东省海丰县彭湃纪念医院经临床诊断的18例肝硬化合并肝癌、门静脉癌栓患者(癌栓组)和12例肝硬化合并门静脉血栓患者(血栓组)的临床资料。所有患者行MSCT平扫,以及动脉期、门静脉期及延迟期3期增强扫描,并采用多平面重建(MPR)和5 mm厚度最大密度投影(MIP)重建技术对门静脉行3D重建。观察门静脉癌栓和血栓的影像特征、分布情况及侧支循环血管形成情况,比较癌栓和血栓在平扫和增强扫描各时相的密度差异。结果 癌栓组中,CT平扫12例呈低密度并血管增粗,6例呈等密度;CT增强扫描显示动脉期癌栓均呈不均匀强化、15例可见滋养血管影,门静脉期4例呈稍高密度、5例呈等密度、9例呈低密度,延迟期均呈低密度;18例门静脉癌栓均累及门静脉左或/和右支, 仅6例累及门静脉主干。血栓组中,CT平扫3例呈等密度, 3例呈低密度,6例呈稍高密度;CT增强扫描血栓均无强化,门静脉期及延迟期血栓部位无对比剂充盈;12例中,11例门静脉血栓累及门静脉主干,6例血栓延伸至左叶或/和右叶门静脉分支。门静脉癌栓和血栓在CT平扫和增强扫描的延迟期密度的差异均无统计学意义(P值均＞0.05),而增强扫描的动脉期和门静脉期,癌栓密度明显高于血栓,差异均有统计学意义(P值均＜0.05)。癌栓累及门静脉左或/和右支的概率明显高于血栓,而血栓累及门静脉主干的概率明显高于癌栓,差异均有统计学意义(P值均＜0.05)。结论 结合MSCT平扫及3D重建技术,能客观显示肝硬化患者门静脉癌栓与门静脉血栓的影像特点及其累及范围,能为病变诊断提供客观依据,从而指导临床选择合适的治疗方案。     

Splenectomy ameliorates portal pressure and anemia in animal models of cirrhotic and non-cirrhotic portal hypertension

PurposePortal hypertension (PH)-associated splenomegaly is caused by portal venous congestion and splanchnic hyperemia. This can trigger hypersplenism, which favors the development of cytopenia. We investigated the time-dependent impact of splenectomy on portal pressure and blood cell counts in animal models of non-cirrhotic and cirrhotic PH.Materials and methodsNinety-six rats underwent either partial portal vein ligation (PPVL), bile duct ligation (BDL), or sham operation (SO), with subgroups undergoing additional splenectomy. Portal pressure, mean arterial pressure, heart rate, blood cell counts and hemoglobin concentrations were evaluated throughout 5 weeks following surgery.ResultsFollowing PPVL or BDL surgery, the animals presented a progressive rise in portal pressure, paralleled by decreased mean arterial pressure and accelerated heart rate. Splenectomy curbed the development of PH in both models (PPVL: 16.25 vs. 17.93 ?mmHg, p ?= ?0.083; BDL: 13.55 vs. 15.23 ?mmHg, p ?= ?0.028), increased mean arterial pressure (PPVL: +7%; BDL: +9%), and reduced heart rate (PPVL: ?10%; BDL: ?13%). Accordingly, splenectomized rats had lower von Willebrand factor plasma levels (PPVL: ?22%; BDL: ?25%). Splenectomy resulted in higher hemoglobin levels in PPVL (14.15 vs. 13.08 ?g/dL, p ?< ?0.001) and BDL (13.20 vs. 12.39 ?g/dL, p ?= ?0.097) animals, and significantly increased mean corpuscular hemoglobin concentrations (PPVL: +9%; BDL: +15%). Thrombocytopenia only developed in the PPVL model and was alleviated in the splenectomized subgroup. Conversely, BDL rats presented with thrombocytosis, which was not affected by splenectomy.ConclusionsSplenectomy improves both cirrhotic and non-cirrhotic PH, and ameliorates the hyperdynamic circulation. Hypersplenism related anemia and thrombocytopenia were only significantly improved in the non-cirrhotic PH model.     

Dosimetric investigation and portal dose image prediction using an amorphous silicon electronic portal imaging device.

A two step algorithm to predict portal dose images in arbitrary detector systems has been developed recently. The current work provides a validation of this algorithm on a clinically available, amorphous silicon flat panel imager. The high-atomic number, indirect amorphous silicon detector incorporates a gadolinium oxysulfide phosphor scintillating screen to convert deposited radiation energy to optical photons which form the portal image. A water equivalent solid slab phantom and an anthropomorphic phantom were examined at beam energies of 6 and 18 MV and over a range of air gaps (approximately 20-50 cm). In the many examples presented here, portal dose images in the phosphor were predicted to within 5% in low-dose gradient regions, and to within 5 mm (isodose line shift) in high-dose gradient regions. Other basic dosimetric characteristics of the amorphous silicon detector were investigated, such as linearity with dose rate (+/- 0.5%), repeatability (+/- 2%), and response with variations in gantry rotation and source to detector distance. The latter investigation revealed a significant contribution to the image from optical photon spread in the phosphor layer of the detector. This phenomenon is generally known as "glare," and has been characterized and modeled here as a radially symmetric blurring kernel. This kernel is applied to the calculated dose images as a convolution, and is successfully demonstrated to account for the optical photon spread. This work demonstrates the flexibility and accuracy of the two step algorithm for a high-atomic number detector. The algorithm may be applied to improve performance of dosimetric treatment verification applications, such as direct image comparison, backprojected patient dose calculation, and scatter correction in megavoltage computed tomography. The algorithm allows for dosimetric applications of the new, flat panel portal imager technology in the indirect configuration, taking advantage of a greater than tenfold increase in detector sensitivity over a direct configuration.