Oleic acid-induced lung injury: thin-section CT evaluation in dogs

PURPOSE: To validate lung attenuation measurements for quantifying extravascular lung water in oleic acid-induced pulmonary edema, compare subjective assessment with attenuation measurements, and compare this permeability-type pulmonary edema with hydrostatic-type pulmonary edema. MATERIALS AND METHODS: Thin-section computed tomography (CT) and pulmonary hemodynamic examinations were performed sequentially in six dogs before and after intravenous administration of 0.08 mg of oleic acid per kilogram of body weight. Extravascular lung water and pulmonary capillary pressure were measured. Results were compared with those reported in a canine model of hydrostatic edema. RESULTS: Oleic acid induced a progressive increase in extravascular lung water without a change in capillary pressure, which indicated pure permeability-type edema. Ground-glass opacification was detected as soon as extravascular lung water increased. Lung attenuation was highly correlated to extravascular lung water (r = 0.76, P<.001), as in hydrostatic edema, but was characterized by an almost absent gravitational gradient. CONCLUSION: Thin-section CT is sensitive for early detection and quantification of oleic acid-induced pulmonary edema in a canine model. Different from early canine hydrostatic edema, which is characterized by a gravitational gradient, early oleic acid-induced pulmonary edema in a supine dog is characterized by nearly homogeneous distribution, except for ventral sparing.     

高原性肺水肿与心、肾肺水肿X线表现的比较

为了评价胸部X线征象在鉴别不同病因肺水肿的价值,作者对27例高原性肺水肿和心肾肺水肿各25例的6种X线征象作了比较分析.结果提示:根据这些胸部X线征象,高原性肺水肿能与其他二型肺水肿区别开来.最后作者对各种X线征象的病理生理基础,高原性肺水肿形成的机理和X线表现等结合文献作了讨论.     

Plain X-ray diagnosis of noncardiogenic edema]

Noncardiogenic edema is pulmonary edema without increased precapillary blood pressure of the lung. The causes of noncardiogenic edema include decreased blood osmotic pressure, increased permeability of basement membrane, and disturbed lymphatic drainage. We describe the plain X-ray findings of noncardiogenic pulmonary edema as they correlate with the pathophysiology of pulmonary water influx from blood vessels into the extravascular space. We discuss certain selected causes of noncardiogenic edema such as ARDS and high altitude, focusing on the differential diagnosis between cardiogenic edema and noncardiogenic edema and the causes of noncardiogenic edema.     

Hydrostatic pulmonary edema: evaluation with thin-section CT in dogs

PURPOSE: To identify the hemodynamic determinants of ground-glass opacification on thin-section computed tomographic (CT) scans of hydrostatic pulmonary edema and to compare attenuation and subjective assessments of ground-glass opacification with extravascular lung water. MATERIALS AND METHODS: Left atrial pressure, pulmonary arterial pressure, effective pulmonary capillary pressure, and extravascular lung water were measured in six dogs before and during progressive increase of effective pulmonary capillary pressure. A thin-section CT scan was obtained at each step. Lung attenuation and subjective assessments of ground-glass opacification were compared with hemodynamic variables and extravascular lung water. RESULTS: Ground-glass opacification was identified when effective pulmonary capillary pressure equaled critical pulmonary capillary pressure. Extravascular lung water increased, and the distribution curve of lung attenuation coefficients shifted to higher attenuation from the second measurement at an effective pulmonary capillary pressure greater than the critical pulmonary capillary pressure. Attenuation was highly correlated (r = 0.98, P < .001) with extravascular lung water; ground-glass opacification was detected before a significant (P = .615, analysis of variance) increase in extravascular lung water. CONCLUSION: Thin-section CT depicts ground-glass opacification when effective pulmonary capillary pressure equals critical pulmonary capillary pressure and before a detectable increase in extravascular lung water. Attenuation reflects extravascular lung water.     

Extravascular lung water in patients with congestive heart failure. Difference between patients with acute and chronic myocardial disease

Extravascular lung water was assessed using a double-indicator dilution technique (thermal-green dye) in 15 men who had radiographic and clinical evidence of cardiogenic interstitial and alveolar pulmonary edema. Eight patients had suffered an acute myocardial infarction and seven had a history of chronic congestive cardiomyopathy and worsening of previous clinical signs and symptoms. At the same level of pulmonary capillary wedge pressure and similar arterial oxygen tensions extravascular lung water was significantly greater in the group with chronic congestive cardiomyopathy (p less than .05). The two groups did not differ with respect to systemic arterial pressure, resistance, or cardiac index.     

Usefulness of lung ultrasound in the bedside distinction between pulmonary edema and exacerbation of COPD

This review discusses the usefulness of bedside lung ultrasound in the diagnostic distinction between different causes of acute dyspnea in the emergency setting, particularly focusing on differential diagnosis of pulmonary edema and exacerbation of chronic obstructive pulmonary disease (COPD). This is possible using a simple unit and easy-to-acquire technique performed by radiologists and clinicians. Major advantages include bedside availability, absence of radiation, high feasibility and reproducibility, and cost efficiency. The technique is based on analysis of sonographic artifacts instead of direct visualization of pulmonary structures. Artifacts are because of interactions between water-rich structures and air and are called “comet tails” or B lines. When such artifacts are widely detected on anterolateral transthoracic lung scans, we diagnose diffuse alveolar-interstitial syndrome, which is often a sign of acute pulmonary edema. This condition rules out exacerbation of COPD as the main cause of an acute dyspnea. The author did not receive personal or financial support from or has any affiliations or involvement with any organization with financial interest in the subject matter.     

Ultrasound lung comets induced by repeated breath-hold diving, a study in underwater fishermen

Pulmonary edema has been reported in breath-hold divers during fish-catching diving activity. The present study was designed to detect possible increases in extravascular lung water (EVLW) in underwater fishermen after a competition. Thirty healthy subjects were studied. They participated in two different 5-h fish-catching diving competitions: one organized in the winter (10 subjects) and one organized in the autumn (20 subjects). A questionnaire was used to record underwater activity and note respiratory problems. An increase in EVLW was investigated from the detection of ultrasound lung comets (ULC) by chest ultrasonography. Complementary investigations included echocardiography and pulmonary function testing. An increase in EVLW was detected in three out of 30 underwater fishermen after the competition. No signs of cardiovascular dysfunction were found in the entire population and in divers with an increase in the ULC score. Two divers with raised ULC presented respiratory disorders such as cough or shortness of breath. Impairment in spirometric parameters was recorded in these subjects. An increase in EVLW could be observed after a fish-catching diving competition in three out of 30 underwater fishermen. In two subjects, it was related to respiratory disorders and impairment in pulmonary flow.     

心原性肺水肿31例的X线征象分析

目的　探讨心原性肺水肿的X线胸片的表现 ;提高对肺水肿的X线诊断的认识。方法　选取 31例诊断明确的心原性肺水肿患者 ,分析其治疗前后的正、侧位胸片的X线表现。结果　 31例患者的X线征象有 :反转血流现象 2 9例 ,KerleyB线和A线各有 18例和 5例 ,胸膜下水肿和支气管袖口征各有 15例和 18例 ,肺门混浊征和肺纹理模糊 2 4例 ,蝶翼征和运动边缘线各有 5例和 2例 ,单侧肺水肿和两肺不对称的肺水肿 6例 ,胸腔积液 2 4例 ,心脏阴影扩大 2 9例。结论　反转血流现象 ;KerleyB线形成 ;肺门混浊征和肺纹理模糊 ;以及少量胸腔积液 ,心胸比例增大等应为心源性肺水肿常见的且较为特征性的X线胸片表现。     

Radiographic diagnosis of cardiogenic pulmonary edema]

Development of pulmonary edema (increased extravascular lung water) is a common and sometimes life-threatening clinical problem in critical-care unit patients. There are three principal causes: cardiac failure, overhydration, and increased pulmonary capillary permeability. Among these, cardiogenic edema consists of left heart failure and overhydration. Determining the specific cause of any given case of pulmonary edema is important and leads to more rapid and definitive treatment. A plain chest film can often explicate the cause of edema with a high degree of accuracy if careful attention is given to certain radiographic features. The principal features useful for correctly determining the cause of edema in a high percentage of cases are the distribution of pulmonary blood flow, distribution of pulmonary edema, and vascular pedicle width. Ancillary features are pulmonary blood volume, bronchial cuffing, septal lines, pleural effusion, and air bronchograms. Cardiac size and shape as well as specific intracardiac calcifications could also help distinguish cardiogenic from noncardiogenic pulmonary edema.     

Relative quantification of pulmonary edema with noncontrast-enhanced MRI

Pulmonary edema is a debilitating effect of acute respiratory distress syndrome. The ability to measure it noninvasively with high sensitivity and in three dimensions could be useful in not only detection but also in assessment and guidance of treatment. To this end, a three-dimensional MRI pulse sequence to measure the formation of edema was developed and tested. Another sequence was tested to measure blood flow in distal pulmonary arteries. Pulmonary edema was induced in nine dogs via venous injections of oleic acid. Edema was verified by wet-to-dry weight ratio (5.30 ± .38) and extravascular lung water at baseline (2.03 ± 1.12 ml/g dry lung weight) versus postinjury (3.00 ± 1.45 ml/g) (P < .005). The signal-to-noise ratio within the lungs increased from 5.47 ± 1.00 at baseline to 7.51 ± 1.96 (P < .005), and the time course of edema formation was resolved. Results from MR phase-contrast blood flow measurements were variable. The authors conclude that the three-dimensional scan provides a sensitive relative quantification of pulmonary edema formation without the use of contrast agents or ionizing radiation.     

高原肺水肿的CT诊断

目的：探讨高原肺水肿的CT诊断价值。方法：对16例急性高原适应不全患者进行胸部CT检查，总结其CT表现。结果：其CT表现：（1）早期为磨玻璃样密度增高影，多出现于下叶背段及后基底段，且右下叶早于左下叶；（2）中期为云状密度增高影，若早期未得到及时有效的治疗，则病变密度逐渐增高而形成云絮状密度增高影；（3）晚期可发展到上叶后段及前段，病变充满整个肺叶，可见受累肺段支气管充气；（4）右肺表现重于左肺。结论：CT是高原肺水肿较理想的检查手段。对于高原肺水肿，CT诊断的准确率达100％。     

继发于自发性颅内出血的神经源性肺水肿的影像学表现

目的:探讨自发性颅内出血并发神经源性肺水肿(NPE)的影像表现及与临床表现的相关性.方法:回顾性分析经临床证实的自发性颅内出血并发NPE的5个病例,均行CT平扫及胸部X线片检查,分析其表现及临床特征.结果:5例自发性颅内出血并发NPE中,脑干出血2例,小脑出血1例,大脑半球出血1例,自发性蛛网膜下腔出血1例.4例血肿均有破入临近脑室和/或蛛网膜下腔.5例患者的胸部X线片均示不同程度的肺水肿改变.治愈2例,死亡3例.结论:自发性颅内出血并发NPE患者的头颅CT均可见程度不同的颅内出血改变,其肺部表现为轻重不等的肺水肿征象,排除原发心、肺疾患及输液过快等因素,均应提示NPE,以免贻误抢救时机.     

高原肺水肿影像表现及其病理基础的实验研究

目的探讨高原肺水肿的影像特点及其病理基础.材料与方法利用减压舱模拟海拔7000m高原条件观察家猫缺氧24、48和72小时胸部X线、CT表现及其病理改变.结果实验性高原肺水肿早期X线、CT表现为肺纹理增粗、模糊,肺野周围性分布的斑片状阴影.减压组动物减压后右下肺动脉横径较减压前显著增加(P＜0.05),胸片肺水肿记分与CT值呈显著的线性正相关(r=0.955).主要病理改变为肺出血及肺水肿.结论高原肺水肿胸部X线、CT主要表现为肺野周围性分布的斑片状阴影,对高原肺水肿的诊断有重要意义.     

机械通气对海水淹溺肺水肿兔肺组织学的影响

目的：观察常规机械通气(CMV)和高频喷射通气(HFJV)治疗兔海水淹溺肺水肿(PE—SWD)后肺组织病理学改变。方法：应用CMV和HFJV对14只PE—SWD新西兰大白兔进行救治，着重观察治疗前后肺组织病理学的改变。结果：PE—SWD兔HE染色见肺泡及肺间质水肿明显，多数肺泡腔内见均匀红染；肺泡壁毛细血管充血扩张，有肺透明膜形成；可见局灶性肺不张、气肿；肺间质、肺泡腔内见较多炎细胞浸润。CMV、HFJV治疗组上述病变明显减轻，CMV组减轻更明显。结论：机械通气治疗后，PE—SWD兔肺组织水肿、炎细胞浸润等病理学改变有明显改善。     

Pulmonary circulation

Evaluation of the pulmonary vasculature is mainly indicated in patients with suspected pulmonary thromboembolism. The routine procedure so far is ventilation-perfusion scintigraphy alone or in combination with diagnostic assessment of the legs to rule out deep venous thrombosis. The results are still not reliable for the majority of patients. In the case of equivocal diagnosis, invasive conventional angiography is considered the gold standard. With steady improvements in tomographic imaging techniques, such as computed tomography (CT) or magnetic resonance imaging (MRI), non-invasive alternatives to the routine diagnostic work-up are given. Helical CT and CTA techniques are already in clinical use and estimated to sufficiently serve the demands for detection/exclusion of pulmonary thromboembolism. The disadvantages mainly concern peripheral disease and reconstruction artifacts. MRI and MR angiography have been implemented in the diagnosis of pulmonary vascular disease since the introduction of contrast-enhanced MRA. In breath-hold techniques, the entire lung vascularization can be delineated and thromboemboli can be detected. The clinical experience in this field is limited, but MRI has the potential to demonstrate its superiority over CT due to its improved delineation of the vascular periphery and the more comprehensive three-dimensional reconstruction. Received: 20 January 1998; Accepted: 10 February 1998     

The effect of pulmonary edema on proton nuclear magnetic resonance relaxation times

This study was done to determine the effect of permeability pulmonary edema on proton nuclear magnetic resonance (NMR) relaxation times. Permeability edema was induced in rats by the intravenous injection of alloxan in saline. Control animals received only saline. The rats were ventilated through a tracheostomy; and after a time sufficient for the edema to become uniform, they were sacrificed. T1, and T2 and extravascular lung water were measured on lung samples. A linear relationship was found between the relaxation times and the extravascular lung water. Any diffuse alveolar process including pulmonary edema can increase proton density as well. The T1 and T2 relaxation times may be used to distinguish among different causes of increased proton density in the lung.     

Pathophysiology,clinical features and radiological findings of differentiation syndrome/all-trans-retinoic acid syndrome

In acute promyelocytic leukemia, differentiation therapy based on all-trans-retinoic acid can be complicated by the development of a differentiation syndrome (DS). DS is a life-threatening complication, characterized by respiratory distress, unexplained fever, weight gain, interstitial lung infiltrates, pleural or pericardial effusions, hypotension and acute renal failure. The diagnosis of DS is made on clinical grounds and has proven to be difficult, because none of the symptoms is pathognomonic for the syndrome without any definitive diagnostic criteria. As DS can have subtle signs and symptoms at presentation but progress rapidly, end-stage DS clinical picture resembles the acute respiratory distress syndrome with extremely poor prognosis; so it is of absolute importance to be conscious of these complications and initiate therapy as soon as it was suspected. The radiologic appearance resembles the typical features of cardiogenic pulmonary edema. Diagnosis of DS remains a great skill for radiologists and haematologist but it is of an utmost importance the cooperation in suspect DS, detect the early signs of DS, examine the patients’ behaviour and rapidly detect the complications.     

R?ntgen appearances of pulmonary edema and their clinical and physiologic correlates (author's transl)]

With the rapid increase in the number of intensive care units in surgical and medical departments knowledge of early radiologic signs of pulmonary edema gains in importance. On the basis of investigations by American authors typical changes in the distribution of pulmonary blood supply can be shown, in good correlation with pressure changes in the pulmonary vein in left heart failure. When pressure rises in the pulmonary vein the well-know changes of interstitial or alveolar (acinary) pulmonary edema arise. Differential diagnosis between pulmonary edema due to left heart failure and edema from other causes is aided on the one hand by the presence of interstitial pulmonary edema and redistribution of blood, on the other hand by the abnormaly large heart and configuration. Neither R?ntgen appearances nor type of distribution of pulmonary edema are specific for any given cause. In all cases of pulmonary edema, the primary-peripheral excepted, clinical signs either occur later than X ray findings or will be absent altogether. Respiratory physiology permits, according to the severity of the edema, proof of hypoxemia with pronounced differences in the regional ventilation-perfusion quotient up to marked reduction of compliance and increase of resistance.     

慢支肺气肿并发肺水肿的X线表现

本文报导23例慢支肺气肿并发左心衰间质性肺水肿胸片的X线表现如下:(1)上肺静脉扩张>3mm,(2)肺门扩大模糊,(3)肺门血管结节影和支气管袖口征,(4)胸膜下水肿,(5)心脏增大,(6)两肺纹理增粗模糊,(7)两肺幕帘征又称瑞氏乳酪征,呈不均匀分布于两肺门周围或中下肺野区,透过境界不清的淡薄密度增高阴影中可见到不规则网格状透亮阴影,认为是慢支肺气肿间质性肺水肿的特殊X线表现。本文结合慢支肺气肿左心衰肺水肿的机理,对支气管袖口征等和特殊的幕帘征作了较详细的讨论,所有这些肺水肿的X线表现,在适当治疗后,均迅速消退或消失,证实左心衰肺水肿的存在。     

Non-traumatic thoracic emergencies: CT diagnosis of acute pulmonary embolism: the first 10 years

Over the past 10 years, spiral CT angiography of the pulmonary arteries has reached a high accuracy in the evaluation of pulmonary embolism. Major advantages of CT compared with ventilation/perfusion lung scintigraphy and pulmonary angiography is direct visualization of clots in the pulmonary arteries, and to provide alternative findings or diagnosis. The recent introduction of multislice CT has improved the evaluation of peripheral pulmonary arteries, enabling high-resolution CT examinations over the entire thorax in a short breathhold. The examination techniques, imaging findings, pitfalls, and results of CT in the diagnosis of pulmonary embolism are reviewed in comparison with other diagnostic tests.