Portal blood flow: measurement with MR imaging

Portal blood flow was measured by means of direct bolus imaging (DBI), a method of measuring flow velocity with magnetic resonance imaging. DBI allows immediate visualization of fluid movement, thereby enabling calculation of a flow velocity from fluid displacement. In a study of 14 healthy male volunteers, portal blood flow was measured with electrocardiographic gating during the 18 seconds subjects could suspend respiration. These measurements showed a close correlation (r = .968) with those obtained by means of Doppler ultrasound (US). Increases in portal blood flow after oral administration of ethanol and glucose were measured with DBI. Glucose caused a statistically greater increase in portal blood flow volume in healthy control subjects than in patients with chronic hepatitis. Blood sugar, on the other hand, showed a significantly greater increase in these patients, possibly reflecting the greater vascular resistance of the liver. DBI is a useful noninvasive method of measuring portal blood flow without the limitations imposed on Doppler US by obesity and intestinal gas.     

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.     

"Congestion index" of the portal vein

The "congestion index" is used to mean the ratio between the cross-sectional area (cm2) and the blood flow velocity (cm/sec) of the portal vein, as determined by a duplex Doppler system. The indices as determined in normal subjects and patients with liver disease were as follows: normal subjects (n = 85), 0.070 +/- 0.029 cm X sec; acute hepatitis (n = 11), 0.071 +/- 0.014 cm X sec; chronic active hepatitis (n = 42) 0.119 +/- 0.084 cm X sec; cirrhosis (n = 72), 0.171 +/- 0.075 cm X sec; and idiopathic portal hypertension (n = 11), 0.180 +/- 0.107 cm X sec. There was a statistically significant difference between the congestion indices from the normal subject group and indices obtained from patients with chronic hepatitis, cirrhosis, and idiopathic portal hypertension. A weak positive correlation was obtained between the congestion index and the portal venous pressure, measured simultaneously through a percutaneously placed catheter (n = 64, r = 0.45, p less than 0.01). It is suggested that the congestion index reflects the pathophysiological hemodynamics of the portal venous system in portal hypertension.     

Portal venous hemodynamics in chronic liver disease: effects of posture change and exercise

Changes of portal hemodynamics with the progression of chronic liver disease and changes caused by body posture and physical exercise were investigated using an ultrasonic pulsed Doppler flowmeter in healthy adults and in patients with chronic persistent hepatitis, chronic active hepatitis, and cirrhosis. Portal venous velocity was significantly reduced in patients with chronic active hepatitis, cirrhosis without a large splenorenal shunt, and cirrhosis with a large splenorenal shunt, compared with normal subjects and patients with chronic persistent hepatitis. Portal venous flow, by contrast, was significantly reduced only in patients with cirrhosis and a large splenorenal shunt compared with normal subjects and with the other three groups; there was no significant difference in portal venous flow among the latter four groups. Both portal venous velocity and flow showed a tendency toward further reduction in patients with cirrhosis who had hepatofugal flow of part of the superior mesenteric venous blood into the splenic vein and a large splenorenal shunt. Both exercise and posture change from supine to sitting significantly reduced portal venous velocity and portal venous flow in normal subjects, as well as in the patients with chronic liver disease.     

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.     

慢性重型肝炎门静脉系统血流动力学变化的研究

目的探讨慢性重型病毒性肝炎门静脉系统血流动力学变化.材料和方法应用多普勒超声检测30例慢性重型肝炎患者门静脉系统血流动力学变化,并与正常组(51例)、慢性肝炎组(61例)、代偿期肝硬化组(46例)、失代偿期肝硬化组(36例)进行对照研究.结果慢性重型肝炎门静脉直径稍宽于正常组,而明显低于失代偿期肝硬化,与慢性肝炎组及代偿期肝硬化无差异;门静脉血流速度、血流量显著低于对照各组;脾脏长径、脾静脉直径较正常组和慢性肝炎组增大、增宽,但明显小于失代偿期肝硬化,与代偿期肝硬化无差异;脾静脉血流量与各组比较均没有明显增加;脐静脉重开率显著高于慢性肝炎组及代偿期肝硬化组,与失代偿期肝硬化组无差异.结论慢性重型肝炎容易形成门静脉高压,门静脉血流灌注量明显减少,造成肝脏微循环障碍.     

Hepatic flow parameters measured with MR imaging and Doppler US: correlations with degree of cirrhosis and portal hypertension

PURPOSE: To determine the correlations between hemodynamic parameters of hepatic flow measured with magnetic resonance (MR) imaging and Doppler ultrasonography (US) and the severity of cirrhosis and portal hypertension. MATERIALS AND METHODS: Forty-six patients referred for measurements of portal venous pressure (three with normal liver, 12 with chronic hepatitis, and 31 with cirrhosis [10 with Child-Pugh class A cirrhosis; 13 with class B cirrhosis; and eight with class C cirrhosis]) were included in the study. Apparent liver perfusion, apparent arterial and portal perfusion, portal fraction, distribution volume, and mean transit time were measured with dynamic contrast material-enhanced MR imaging. Portal velocity, portal flow, congestion index, right hepatic artery resistance index, and modified hepatic index were measured with Doppler US. Results in patients with cirrhosis and those without cirrhosis were compared with the Wilcoxon rank sum test. Correlations were assessed with Spearman rank correlation coefficients. RESULTS: With MR imaging, all flow parameters except distribution volume were significantly different between patients with and those without cirrhosis (P <.05). There was a significant correlation between all flow parameters measured with MR imaging and portal pressure (P <.02). Apparent arterial (P =.024) and portal (P <.001) perfusion, portal fraction (P <.001), and mean transit time (P =.004) were correlated with Child-Pugh class. Flow parameters measured with Doppler US did not differ significantly between patients with and those without cirrhosis. Only right hepatic arterial resistance (P <.007) and portal flow (P <.043) were weakly (r < 0.7) correlated with portal pressure. No Doppler US parameter was correlated with Child-Pugh class. CONCLUSION: Hepatic flow parameters measured with MR imaging correlate with the severity of cirrhosis and portal hypertension. Doppler US parameters are only weakly correlated with portal pressure.     

Can Doppler sonography grade the severity of hepatitis C-related liver disease?

OBJECTIVE: Many authors have claimed that Doppler sonography indexes are of value in grading and assessing diffuse liver disease. However, there is much controversy regarding the reliability and reproducibility of these techniques. We performed a prospective study to evaluate whether these methods can grade disease in a well-stratified cohort of patients with hepatitis C virus (HCV)-related liver disease. SUBJECTS AND METHODS: Sixty-five patients with biopsy-proven HCV-related liver disease were recruited, and Doppler sonography was performed by one operator. The patients were classified into one of the following three groups on the basis of the Ishak-modified histologic activity index (HAI) fibrosis (F) and necroinflammatory (NI) scores: mild hepatitis (F < or = 2 and NI < or = 3), moderate or severe hepatitis (3 < or = F < 6 or NI > or = 4), or cirrhosis (F = 6/6). We measured the following Doppler indexes: main hepatic artery peak velocity (Vmax) and resistive index, main portal vein peak velocity (Vmax), and maximal portal vein diameter and circumference that allowed calculation of the portal vein congestive index (portal vein area and portal vein velocity). The ratio of the hepatic artery velocity (Vmax) to the portal vein velocity (Vmax) was also calculated, and the phasicity (triphasic, biphasic, or monophasic) of the hepatic veins of each patient was recorded. We also measured the maximal spleen length longitudinally. RESULTS: A total of 65 patients with liver disease (mild hepatitis, n = 20; moderate or severe hepatitis, n = 25; cirrhosis, n = 20) with biopsy-proven HCV-related liver disease were studied. Optimal hepatic arterial traces were obtained in only 30 patients and portal vein circumference in 18 patients. No significant differences were observed in the Doppler indexes with increasing severity of liver disease. Five (29%) of 17 patients with mild hepatitis had an abnormal hepatic vein trace (i.e., biphasic or monophasic) compared with 11 (55%) of 20 patients with moderate or severe hepatitis and 12 (60%) of 20 patients with cirrhosis. The only index to show a significant intergroup difference was splenic length (analysis of variance, p < 0.001), but there was still overlap between the groups. CONCLUSION: Doppler-derived indexes, which have previously been recommended for the assessment of severity in chronic liver disease, are difficult to reproduce reliably and therefore have a limited clinical role in the noninvasive assessment of hepatic fibrosis or inflammation.     

Pulsed Doppler flow as a criterion of portal venous velocity: comparison with cineangiographic measurements

An ultrasonic sector scanner and pulsed Doppler flowmeter were combined to measure portal venous velocity in 19 patients with portal hypertension and compared with cineangiographic mapping of a droplet of oil released into the portal vein. In 12 patients, measurements were made before and after pitressin [7] or ranitidine [5]. With the Doppler method, maximum basal portal venous velocity was 17.0 +/- 3.9 cm/sec., while average cineangiographic velocity was 8.5 +/- 2.7 cm/sec., a significant difference (p less than 0.001). After pitressin, velocity decreased to 8.3 +/- 2.7 cm/sec. with the Doppler method and 3.6 +/- 1.0 cm/sec. with cineangiography. Ranitidine did not produce an appreciable change. Doppler and cineangiographic velocity measurements exhibited significant correlation over a wide range of values (r = 0.960). Thus the pulsed Doppler method may give accurate values of portal venous velocity if they are corrected to cineangiographic values. Flow can be calculated from velocity and the cross-sectional area of the portal vein as measured on the sonogram. The Doppler method is simple and noninvasive and is particularly useful in studying changes in portal hemodynamics.     

Doppler ultrasonography evaluation of paraumbilical vein and portal hypertension

Portal hypertension is associated to the development of portosystemic collateral veins, particularly the paraumbilical vein. PURPOSE: To evaluate the biometric and hemodynamic characteristics of the portal vessels related to the presence of a patent paraumbilical vein, in the setting of portal hypertension secondary to hepatosplenic schistosomiasis. METHODS: 75 patients with portal hypertension secondary to hepatosplenic schistosomiasis were evaluated by Doppler US. The patients were studied based on the presence (group B) or not (Group A) of a patent paraumbilical vein. The diameter and blood flow velocity of the portal vessels and of the paraumbilical vein were recorded. RESULTS: The paraumbilical vein was detected in 17.33% of patients. The results showed an increase of the diameter of the main and left portal vessels whenever a patent paraumbilical vein was present (portal vein: A = 1.14 +/- 0.29 cm/B = 1.33 +/- 0.16 cm; left branch: A = 0.95 +/- 0.25 cm/B = 1.30 +/- 0.24 cm). The mean blood flow velocity was also increased in the portal trunk (A = 15.96 +/- 6.17 cm/sec/B = 19.82 +/- 6.26 cm/sec) and in the left portal branch (A = 14.77 +/- 4.29 cm/sec/B = 19.92 +/- 6.88 cm/sec). CONCLUSION: The presence of a patent paraumbilical vein is related to significant biometric and hemodynamic variations in the portal venous system, in the setting of portal hypertension secondary to hepatosplenic schistosomiasis.     

Duplex sonography of the splenoportal axis

48 patients with partial or complete portal vein thrombosis or tumor stenosis were examined by pulsed Doppler duplex scanning. In addition to the analysis of morphological changes, the pulsed Doppler duplex system yields functional data on the acceleration of blood flow in stenosis, flow in partial thrombosis and in differentiation between tubular cystic structures like arterial vessels, venous collaterals and dilated bile ducts. Qualitative and quantitative measurements of portal blood flow were performed in 55 cirrhotics and 15 healthy volunteers. Portal venous velocity and portal venous blood flow were significantly reduced in patients with cirrhosis. In 46 cases a hepatopetal blood flow was shown. In five cases a hepatofugal flow and in four cases a stagnant flow was found in the portal vein. Spontaneous portal systemic collaterals with hepatofugal flow were shown in 41% of cases. 11 patients with surgical portacaval shunts were examined. Patency was demonstrated in five patients where the anastomotic site was visible. Pulsed Doppler duplex sonography proved a valuable tool in the assessment of morphologic changes and revealed qualitative and quantitative data of portal venous hemodynamics.     

应用彩色多普勒超声探讨肝癌患者门静脉逆流与肝癌肝内转移的相关性

为探讨肝癌患者门静脉逆流与肝癌肝内转移的关系,应用灰附超声观测肝炎肝癌组、非肝炎肝癌组门静脉癌栓和癌肿肝内转移情况;彩色多普勒超声检测肝炎肝癌组、非肝炎肝癌组、肝硬化组与对照组门静脉－开动脉瘘及门静脉逆流的发生率。结果显示,肝炎肝癌组门静脉逆流的发生率及门静脉癌栓、癌肿肝内转移发生率均高于非肝炎肝癌组（P＜0.01）;肝硬化组门静脉逆流的发生率高于对照组（P＜0.01）;肝炎肝癌组与非肝炎肝癌组肿块内及周围的门静脉－肝动脉瘘发生率无明显差异（P＞0.05）。提示门静脉逆流是引起肝癌肝与非肝炎肝癌组肿块内及周围的门静脉－肝动脉瘘发生率无明显差别（P＞0.05）。提示门静脉逆流是引起肝癌肝内转移的重要因素。     

Aneurysms of the portal venous system: Gray-scale and color doppler ultrasonographic findings with CT and mri correlation

Two cases of incidentally detected aneurysms involving the portal venous system are described with emphasis on gray-scale and color Doppler ultrasonographic (US) findings. Appearing on US as anechoic masses showing direct luminal continuity with the right portal vein and superior mesenteric vein, the lesions displayed spectral findings characteristic of portal venous system on color Doppler US. Dynamic helical computed tomography (CT) demonstrated simultaneous enhancement with the portal system, while the aneurysms were hypointense owing to flow void on T1-weighted spin-echo magnetic resonance (MR) images.     

Pathologic skeletal muscle perfusion in patients with myositis: detection with quantitative contrast-enhanced US--initial results

PURPOSE: To prospectively determine whether contrast material-enhanced ultrasonography (US) can depict inflammation-induced changes in muscle perfusion for patients suspected of having dermatomyositis or polymyositis and to compare these findings with those of magnetic resonance (MR) imaging and muscle biopsy. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Perfusion in skeletal muscles was quantified with contrast-enhanced intermittent power Doppler US by applying a modified model that analyzed the replenishment kinetics of microbubbles. In 22 patients (16 women, six men; mean age, 52 years +/- 17) who were suspected of having myositis and in 10 healthy volunteers (two women, eight men; mean age, 28 years +/- 4), contrast-enhanced US of the clinically affected right biceps muscle was performed to measure blood flow, blood volume, and blood flow velocity. Additionally, the right upper arm was examined with a 1.5-T unit by using three different MR imaging techniques. Findings were compared with the results of clinical examinations and muscle biopsy. Data for perfusion-related parameters obtained at contrast-enhanced US were analyzed by using a nonparametric Mann-Whitney U test. RESULTS: Eight patients had histologically confirmed myositis and showed significantly higher blood flow velocity (P = .01), blood flow (P = .001), and blood volume (P = .002) at contrast-enhanced US than did patients who did not have myositis. Blood flow velocity (P = .001) and blood flow (P = .002) were significantly higher in patients with myositis than in volunteers. An increase in signal intensity on T2-weighted MR images was found in all patients with myositis, while contrast material enhancement on fat-suppressed T1-weighted MR images was found in only four of seven patients with myositis. CONCLUSION: Initial results show that contrast-enhanced US is a feasible method for noninvasively demonstrating increased perfusion in the involved muscle groups in patients with myositis.     

经颈静脉肝内门-体静脉分流术应用疗效观察

本文报告经颈静脉肝内门-体静脉分流术(TIPSS)14例,成功12例。术后食道静脉曲张明显减轻乃至消失、门脉主干血流速度显著增加、门脉压力平均下降1.48kPa、血小板有所升高、白细胞变化不大、脾脏体积缩小30-60％。本组临床应用结果表明:TIPSS创伤性小,降低门脉压可靠,是治疗门脉高压症的有效方法;此技术成功的关键是术前了解肝静脉与门静脉的空间关系。     

Intrahepatic portal venous system: variations demonstrated with duplex and color Doppler US

Seventeen cases of variations of the intrahepatic portal venous system were investigated with use of duplex and color Doppler ultrasound (US). Seven cases involved absence of the horizontal segment of the left portal vein, with portal supply to the left lobe arising from the right lobe. The 10 remaining cases involved variations of intrahepatic portal branching resulting from absence of the right portal vein, taking four patterns. It is thought that these findings represent variants of normal. These variants are important in two settings: in planning hepatic surgery and in the differential diagnosis of chronic portal vein thrombosis.     

TACE联合内皮抑素对兔VX2肝移植瘤的血流动力学影响的超声评价

目的 利用多普勒超声研究TACE联合内皮抑素栓塞治疗后兔VX2肝移植瘤及肝脏的血流动力学变化。方法 20只荷瘤兔,随机分为对照组和抗血管生成组,每组10只,抗血管生成组经兔肝动脉给予内皮抑素＋超液化碘油＋阿霉素栓塞治疗,对照组以生理盐水代替。1周后多普勒超声观察肿瘤血供及肝动脉、门静脉血流动力学变化,检测结果与治疗前相应血管的多普勒血流参数进行比较。结果 对照组治疗后肝动脉最大血流速度增大（P〈0．05）,肝动脉阻力指数和门静脉血流速度无明显变化（P〉0．05）;抗血管生成组栓塞后肝动脉血流速度明显降低（P〈0．05）,阻力指数增大（P〈0．05）,门静脉血流速度无明显变化（P〈0．05）。治疗前所有病灶内及其周边多普勒超声均可检测出较丰富血流信号,治疗后显示抗血管生成组瘤内及瘤周血流信号均明显减弱,部分消失。结论 TACE联合内皮抑素可有效地阻断兔VX2肝移植瘤供血,多普勒超声可显示该血流的变化,便于对其疗效进行及时评价。     

Liver transplantation: MR angiography with surgical validation

Thirty patients (mean age, 45 years) were evaluated with magnetic resonance (MR) angiography before liver transplantation to assess the accuracy of MR angiography. A series of breath-hold, two-dimensional images were acquired and subsequently processed to form three-dimensional projection angiograms. Graphic information on blood flow in the portal vein was acquired by using presaturation bolus tracking. Correlative duplex ultrasound (US) was performed in 28 patients, and surgical or autopsy correlation was available in all cases. MR angiography demonstrated patency of the portal vein in 26 (96%) of 27 patients, made possible the diagnosis of portal venous occlusion in three of three patients, depicted reversed portal flow in one patient, and provided clear delineation of the extent of varices and specific portosystemic collateral vessels. When duplex US was successful, there was full agreement with MR angiographic results in assessing portal vein patency and flow direction. All of the MR findings were corroborated at surgical exploration or autopsy. The authors conclude that MR angiography is very accurate in the portal system and is valuable in preoperative assessment for liver transplantation.     

Portal hypertension of hepatic origin. A qualitative assessment by color and echo Doppler US

One hundred and twenty-eight subjects were studied: 103 of them were affected with portal hypertension diagnosed both radiologically and clinically. Twenty-five healthy subjects were studied, as a control group, by means of combined real-time US and color Doppler. US parameters were evaluated, specific to chronic hepatopathy, together with the Doppler qualitative parameters relative to splanchnic vessels hemodynamics. Our results allowed a sort of noninvasive angiogram of the portal system to be obtained, which is to be of use for diagnosing portal hypertension, and for assessing its causes, risks, and consequences. This study was also aimed at suggesting an examination protocol for portal hypertension, employing real-time and color Doppler US, which any radiologist with enough experience in abdominal US could use. Color Doppler, although not strictly necessary to obtain good results, dramatically shortens execution times. Moreover, color Doppler allows the method to be more quickly learned.     

肝炎及肝硬变患者高压氧治疗后门静脉血流量的变化

目的　观察高压氧（ＨＢＯ）治疗降低肝炎及肝硬变患者门脉压的作用。方法　对应用ＨＢＯ治疗肝炎（３８ 例）及肝硬变（１４ 例）的患者,采用彩色多普勒超声仪,进行治疗前、后门静脉血流动力学检测。结果　ＨＢＯ治疗１ 次和１０ 次后,门静脉血流量明显减少,与治疗前比,其差异有非常显著意义。结论　ＨＢＯ治疗可降低门脉压,并能避免其它一些方法中出现的减小门脉压力但同时造成肝血氧供给不足的不良作用