Technetium-99m-labeled macroaggregated albumin lung perfusion scan for diagnosis of hepatopulmonary syndrome: A prospective study comparing brain uptake and whole-body uptake

BACKGROUND Hepatopulmonary syndrome (HPS) is an arterial oxygenation defect induced by intrapulmonary vascular dilatation (IPVD) in the setting of liver disease and/or portal hypertension.This syndrome occurs most often in cirrhotic patients(4%-32%) and has been shown to be detrimental to functional status,quality of life,and survival.The diagnosis of HPS in the setting of liver disease and/or portal hypertension requires the demonstration of IPVD (i.e.,diffuse or localized abnormally dilated pulmonary capillaries and pulmonary and pleural arteriovenous communications) and arterial oxygenation defects,preferably by contrast-enhanced echocardiography and measurement of the alveolar-arterial oxygen gradient,respectively.AIM To compare brain and whole-body uptake of technetium for diagnosing HPS.METHODS Sixty-nine patients with chronic liver disease and/or portal hypertension were prospectively included.Brain uptake and whole-body uptake were calculated using the geometric mean of technetium counts in the brain and lungs and in the entire body and lungs,respectively.RESULTS Thirty-two (46%) patients had IPVD as detected by contrast-enhancedechocardiography.The demographics and clinical characteristics of the patients with and without IPVD were not significantly different with the exception of the creatinine level (0.71±0.18 mg/dL vs 0.83±0.23 mg/dL;P=0.041),alveolararterial oxygen gradient (23.2±13.3 mmHg vs 16.4±14.1 mmHg;P=0.043),and arterial partial pressure of oxygen (81.0±12.1 mmHg vs 90.1±12.8 mmHg;P=0.004).Whole-body uptake was significantly higher in patients with IPVD than in patients without IPVD (48.0%±6.1%vs 40.1%±8.1%;P=0.001).The area under the curve of whole-body uptake for detecting IPVD was significantly higher than that of brain uptake (0.75 vs 0.54;P=0.025).The optimal cut-off values of brain uptake and whole-body uptake for detecting IPVD were 5.7%and 42.5%,respectively,based on Youden's index.The sensitivity,specificity,and accuracy of brain uptake 5.7%and whole-body uptake 42.5%for detecting IPVD were23%,89%,and 59%and 100%,52%,and 74%,respectively.CONCLUSION Whole-body uptake is superior to brain uptake for diagnosing HPS.     

肺栓塞时肺灌注显像与肺动脉造影对比动物实验研究

目的 :通过肺栓塞 (PE)动物模型的建立 ,评价肺灌注显像对肺栓塞诊断及疗效观察中的价值。方法 :计算机随机编号 ,取中国实验用小型猪 8头 ,平均体重 16 1± 1 4kg ;建立模型前均行肺灌注显像及选择性肺动脉造影 (CPA) ,取自体猪血 2～ 5ml制血栓 ,通过右心导管将栓子加压注入肺动脉 ;建立PE模型。建立模型后及溶栓治疗后均行肺灌注显像及CPA ,前后采集条件一致。结果 :8头猪造模前CPA均正常 ,肺灌注显像 1例左肺放射性分布不均 ,肺灌注显像特异性 87 5 % (1 8)。 7例存活的模型猪 ,5例造模成功 ,2例不明显 ;以单侧肺观察 ,肺灌注显像与肺动脉造影对比 ,肺灌注显像诊断PE灵敏度 10 0 % ,准确率 90 %。 1例肺动脉造影正常 ,肺灌注显像为亚肺段栓塞 ,与尸检肉眼病理所见一致 ,溶栓后恢复正常血流灌注 ;如果以溶栓治疗有效为标准则准确率增至 10 0 %。溶栓疗效观察肺灌注显像与肺动脉造影二者结果一致。 1例CPA溶通 ,肺灌注显像部分改善 ,尸检证实为部分坏死、实变。结论 :肺灌注显像诊断PE具有很高的敏感性和特异性 ,与肉眼病理所见完全吻合。可作为肺动脉造影前的筛选 ,及临床疗效观察的重要手段     

99m锝-多聚白蛋白动态肺灌注扫描在肝肺综合征早期诊断中的意义

目的探讨99mTcMAA与肺功能测定在肝肺综合征(HPS)早期诊断中的意义.方法选择HPS患者(28例)和无HPS肝硬化患者(30例)测定其肺功能和99mTcMAA,同时以健康人(21例)作为对照.结果HPS组动脉血氧分压(PaO2)、动脉血氧饱和度(SaO2)和肺一氧化碳弥散量(DLco)(分别为6.3、76.3、62.0kpa)显著低于肝硬化组(分别为11.7、90.6、81.6 kPa)(P＜0.01)和对照组(P＜0.01),P(A-a)O2显著增高(P＜0.001);99mTcMAA显示,HPS患者均有肺外脏器(脾、肾、肝和脑)显影,肺内动-静脉分流比和吸入纯氧气时Qs/QT均显著高于肝硬化组(P＜0.01)和对照组(P＜0.001).肝硬化组与对照组比较,DLco显著减低(P＜0.05),P(A-a)O2、肺内动-静脉分流比和吸入100%氧气时Qs/QT显著增高(P＜0.001和P＜0.001),其中有3例(10%)有肺外脏器显影.结论肺功能测定和99mTcMAA是HPS早期诊断的较敏感的指标.     

Tracheal stenosis diagnosed on pulmonary ventilation/perfusion scan

A 68-year-old woman, who had undergone coronary artery bypass surgery 5 months previously, was presented with cough, breathlessness and an elevated D-dimer. She was initially thought to have suffered a pulmonary embolus. A ventilation/perfusion scan demonstrated tracheal stenosis, which required dilation and endobronchial stent deployment. Tracheal stenosis is a well-recognised complication of endotracheal intubation; however, the onset of symptoms is often insidious and the diagnosis delayed.     

Ventilation/perfusion lung scan in pulmonary veno-occlusive disease

Pulmonary veno-occlusive disease (PVOD), a rare form of pulmonary arterial hypertension (PAH), requires histological proof for definitive diagnosis; however, lung biopsy is not recommended in PAH. Recent conjoint European Respiratory Society/European Society of Cardiology guidelines suggest that nonmatched perfusion defects on ventilation/perfusion (V'/Q') lung scanning in PAH patients may suggest PVOD. The aim of our study was to evaluate V'/Q' lung scans in a large cohort of PVOD and idiopathic or heritable PAH patients. V'/Q' lung scans from 70 patients with idiopathic or heritable PAH and 56 patients with confirmed or highly probable PVOD were reviewed in a double-blind manner. The vast majority of V'/Q' lung scans were normal or without significant abnormalities in both groups. No differences in ventilation or perfusion lung scans were observed between PAH and PVOD patients (all p>0.05). Furthermore, no differences were observed between confirmed (n=31) or highly probable PVOD (n=25). Nonmatched perfusion defects were found in seven (10%) idiopathic PAH patients and four (7.1%) PVOD patients (p>0.05). Nonmatched perfusion defects were rarely seen in a large cohort of idiopathic or heritable PAH and PVOD patients. Future recommendations should be amended according to these results suggesting that V'/Q' lung scanning is not useful in discriminating PVOD from idiopathic PAH.     

Chronological change in pulmonary vascular response to hypoxia in hepatopulmonary syndrome

Here we present a case of hepatopulmonary syndrome (HPS) where spontaneous resolution of severe hypoxaemia occurred with the development of pulmonary hypertension over several years after the initial diagnosis of HPS. The pulmonary vascular responses to hypoxia examined before and after the spontaneous resolution of HPS confirmed that the pathogenesis of HPS could be functional and reversible in nature. To the best of our knowledge, this is the first report demonstrating a remarkable change in the pulmonary vascular response to hypoxia before and after the spontaneous resolution of hypoxaemia in HPS.     

Sarcoidosis complicated by cirrhosis and hepatopulmonary syndrome

Sarcoidosis is a multisystem disorder commonly affecting the lungs, but also the liver, with cirrhosis and portal hypertension occurring in fewer than 1% of cases. Although hepatopulmonary syndrome (HPS) is seen in 15% to 20% of patients with cirrhosis of varying causes, it has rarely been associated with sarcoidosis. Also, although a brain abscess is not uncommon in patients with discrete pulmonary arteriovenous malformations, it is rarely seen in patients with the much smaller intrapulmonary vascular dilations that characterize HPS. A patient with an unusual series of uncommon sarcoidosis complications, including cirrhosis with HPS, brain abscess and finally Nocardia meningitis, is reported. The possibility of HPS should be considered in sarcoidosis patients with liver involvement, if gas-exchange abnormalities are out of proportion to the degree of lung involvement. These patients may also be susceptible to a cerebral abscess by paradoxical embolization, and to opportunistic infections due to cirrhosis.     

The pulmonary involvement in portal hypertension: portopulmonary hypertension and hepatopulmonary syndrome

Pulmonary abnormalities are common in patients with advanced chronic liver disease. Two distinct syndromes strictly related to the presence of portal hypertension, but clearly different from a pathophysiologic point of view, have been identified. Portopulmonary hypertension, characterized by an increased pulmonary arterial pressure, is due to a progressive arteriolar vasoconstriction induced by excess local production of vasoconstrictor substances. Hepatopulmonary syndrome results from intrapulmonary microvascular dilation caused by an inadequate synthesis or metabolism of putative pulmonary vasoactive substances leading to a functional vasodilation of the pulmonary vasculature, ultimately leading to hypoxemia. Controversies on pathogenesis imply different tentative therapeutic approaches for the medical management of these conditions. The development of portopulmonary hypertension or the hepatopulmonary syndrome has important clinical and prognostic implications facing the impact of new therapeutic strategies for the management of the main complications of advanced liver diseases on cardiopulmonary function.     

肝肺综合征大鼠血细胞因子和肺血管巨噬细胞观察

目的：观察肝肺综合征大鼠肺组织中肺血管巨噬细胞浸润情况和血浆内毒素水平。方法取 Wistar大鼠30只,随机分为假手术组和胆总管结扎肝纤维化模型组（CBDL 组）,于造模5 w 末处死动物,收集血清及肝肺组织;分别检测血气、内毒素（鲎试验）、一氧化氮（硝酸还原酶法）、肿瘤坏死因子-α（ELISA 法）,观察肝、肺组织病理学变化及肺组织肺血管内巨噬细胞的浸润情况。结果在 CBDL 组动物,5 w 时血气分析示 PaO2为（64.2±7.3） mmHg,显著低于假手术组[（97.7±4.5）mmHg,P〈0.05）];CBDL 组5 w 时血浆内毒素、一氧化氮和肿瘤坏死因子-α分别为（0.2297±0.0362）Eu/ml、（56.2±9.5）μmol/L 和（1.5±0.2）ng/ml,均明显高于假手术组[（0.0938±0.0309） Eu/ml、（32.9±4.3）μmol/L 和（1.5±0.2）ng/ml,P〈0.05）];病理学检查示5 w 时模型组大鼠肝组织可见纤维化表现,肺组织中肺毛细血管扩张、充血,有肺血管巨噬细胞存在。结论在胆总管结扎法诱导的大鼠肝硬化模型中,血清内毒素水平升高、肺血管巨噬细胞浸润和炎性细胞因子分泌增加,可能是肺血管扩张、低氧血症及肝肺综合征发生的重要机制。     

肺血管扩张在肝肺综合征发病机制中作用的研究进展

肺血管扩张是肝肺综合征的主要发病机制,然而导致HPS肺血管扩张的机制相当复杂,至今仍不清楚.目前认为肺血管内巨噬细胞聚积和雌激素升高导致的血管活性因子增多和活性增强可能与此有关,近年来这方面的研究很多,本文对此作一综述.     

肝肺综合征的诊断及治疗研究进展

肝肺综合征是一种与肝病有关的肺血管扩张所致的临床综合征,以动脉氧合障碍为主要表现,是肝脏疾病的肺部严重并发症.其发病机制复杂,发病隐匿,晚期肝病发病率高,目前临床重视不足,远期预后较差,故临床医生需加强对其认识,早期发现,早期诊治,以便改善预后.此文主要对近年来肝肺综合征的诊断及治疗的最新进展进行综述.     

Reversibility by dipyridamole of thallium-201 myocardial scan defects in patients with sarcoidosis

PURPOSE: In order to clarify the significance of anginal pain and myocardial thallium-201 scan defects in cardiac sarcoidosis, the pharmacologic effect of dipyridamole on myocardial perfusion was assessed by planar thallium-201 myocardial scintigraphy in patients with sarcoidosis. PATIENTS and METHODS: Thallium-201 myocardial scintigraphy was performed at rest and after 0.56 mg/kg intravenous dipyridamole during four minutes in 16 patients with sarcoidosis. The myocardial scan (45-degree and 70-degree left anterior oblique, and anterior views) was divided into 15 segments. Results were evaluated by the number of segmental defects and with a global perfusion score (from 0 to 60) by a semi-quantitative index depending on the size and severity of myocardial thallium-201 defects. RESULTS: Thirteen of the 16 patients showed partial or total reversion of their thallium-201 defects on redistribution scanning either at rest or after dipyridamole. The mean (+/- SD) number of myocardial perfusion defects that were present in all the patients decreased from 5.31 +/- 1.78 at rest to 3.25 +/- 2.52 after redistribution (p less than 0.001) and to 2.19 +/- 2.10 after dipyridamole (p less than 0.001). The mean global perfusion score increased from 53.2 +/- 3.0 at rest to 56.2 +/- 2.9 after redistribution (p less than 0.001) and to 57.2 +/- 2.7 after dipyridamole (p less than 0.001). A significant correlation (r = 0.82, p less than 0.001) was found between the increase of global perfusion score on redistribution and after dipyridamole. CONCLUSION: The reversibility of myocardial scan defects is a common finding in sarcoidosis. It makes unlikely the role of scar fibrosis or extensive confluent granulomas as a mechanism for such defects. The effect of dipyridamole suggests the presence of reversible disorders lying at the coronary microvascular level.