Bronchopulmonary arterial anastomosis at the precapillary level in human lung. Visualization using CT angiography compared with microangiography of autopsied lung

PURPOSE: To investigate the interrelationships between the bronchial and pulmonary circulations including the existence of precapillary bronchopulmonary arterial anastomoses. MATERIAL AND METHODS: CT of bronchial arteriography (BAG-CT) was performed in 10 patients and BAG-CT during a pulmonary artery block test (PA-block) in 5 patients with lung cancer. Bronchial and pulmonary circulations were evaluated in 5 autopsied normal lungs by injecting silicone rubber with different colors into the bronchial and pulmonary arteries. RESULTS: BAG-CT correlated well with the findings at silicone rubber injection into lung autopsy samples. BAG-CT demonstrated inflow of contrast medium into the pulmonary artery during PA-block in all cases, while no inflow was observed before and following reversal of PA-block. Mixed silicone rubber was observed in the lobar to subsubsegmental bronchial arteries in all cases and in the subsubsegmental pulmonary artery in one case. CONCLUSION: Precapillary bronchopulmonary arterial anastomoses may exist at the level of the lobar bronchi to the periphery. If either the pulmonary or bronchial circulation is disturbed, flow occurs inside the anastomoses to supplement the other flow, especially flow from the bronchial to the pulmonary arteries via the anastomoses, which occurs within 30 min.     

The peribiliary vascular plexus: the microvascular architecture of the bile duct in the rabbit and in clinical cases

The livers of 30 rabbits were perfused with a silicone rubber solution (Microfil), underwent a clearing process, and were examined with a dissection microscope. The study showed distinct vascular plexuses in and around the bile duct, and two concentric vascular layers present within its wall: the inner capillary and the outer venous. Around the bile duct there was a fine arterial network and a larger venous plexus, which communicated with the capillary and venous plexuses of the bile duct, respectively. The venous plexuses drained directly into the sinusoids or indirectly through the portal vein. The microvascular architecture of the rabbit bile duct correlated well with clinical angiograms exhibiting normal and abnormal peribiliary vascular plexuses. The arterial and venous plexuses dilated and provided collateral circulation in both extrahepatic and intrahepatic arterial and portal vein occlusions, respectively. The peribiliary arteries may be dilated or encased in patients with cholangiocarcinoma or hepatocellular carcinoma invading the bile duct. The animal study and observations on angiograms suggest the existence of transplexal arterioportal communication.     

Selective bronchial arteriography in children.

Twenty nine selective bronchial arteriographies were carried out in 25 children. In 5 cases the findings were normal. In 1 case an aneurysm of the bronchial artery was demonstrated as the source of the bleeding into the bronchus in a case of Rendu-Weber-Osler syndrome. In 1 case a plasmocytoma and in another one a congenital haemangiomatous network with many anastomoses to the pulmonary circulation was demonstrated. In most cases of chronic inflammatory pulmonary disease, the bronchial arteries were dilated and bronchopulmonary anastomoses were visualized. These changes seemed to be a measure of the extent of the disease and of the severity of the functional disturbance in pulmonary tissue, even when only regional. Selective bronchial arteriography is recommended in all cases of haemoptysis, in chronic pulmonary collapse and in chronic inflammatory lung disease in order to determine the source of the bleeding and the extent of involvement of the pulmonary interstitium.     

Computed tomography of inflation-fixed lungs: the beaded septum sign of pulmonary metastases

Radiographic identification of pulmonary metastases has proved to be a challenging problem. We applied high resolution CT (HRCT) to 180 post-mortem lung specimens prepared by a method that allows for direct one-to-one pathologic-radiologic correlation. Of the 180 lungs, 32 had pulmonary metastases. The location, number, size, and interstitial changes were evaluated in 32 cases with pulmonary metastases. The pulmonary metastases were peripheral lesions in 94% of these 32 patients, and multiple tumors were found in 91% of these cases. The metastases were less than 1 cm in diameter in 78%. Twenty-two of the 32 cases (69%) had obvious interstitial changes. In 19 of these 22 cases the interstitial change was characterized by the appearance of a "beaded septum" on HRCT. This beaded septal change corresponded directly to tumor growth in pulmonary capillaries and lymphatics and the septal interstitium. This sign was not noted in any of the specimens with pulmonary edema or fibrosis or in normal lungs. We believe that detection of the beaded septum sign on HRCT is highly suggestive of pulmonary metastases.     

Bronchial artery perfusion scintigraphy to assess bronchial artery blood flow after lung transplantation.

The bronchial arterial system is inevitably interrupted in transplanted lungs when removing the organs from the donor, but it can be reestablished by direct bronchial artery revascularization (BAR) during implantation. The purpose of this study was to visualize and quantify the distribution of bronchial artery perfusion after en bloc double lung transplantation with BAR, by injecting radiolabeled macroaggregated albumin directly into the bronchial artery system. METHODS: BAR was performed using the internal mammary artery as conduit. Patients were imaged 1 mo (n = 13) or 2 y (n = 9) after en bloc double lung transplantation with BAR. Immediately after bronchial arteriography, 100 MBq macroaggregated albumin (45,000 particles) were injected through the arteriographic catheter. Gamma camera studies were then acquired in the anterior position. At the end of imaging, with the patient remaining in exactly the same position, 81mKr-ventilation scintigraphy or conventional intravenous pulmonary perfusion scintigraphy or both were performed. Images were evaluated by visual analysis, and a semiquantitative assessment of the bronchial arterial supply to the peripheral parts of the lungs was obtained with conventional pulmonary scintigraphy. RESULTS: The bronchial artery scintigraphic images showed that the major part of the bronchial arterial flow supplied central thoracic structures, but bronchial artery perfusion could also be demonstrated in the peripheral parts of the lungs when compared with conventional pulmonary scintigraphy. There were no differences between scintigrams obtained from patients studied 1 mo and 2 y post-transplantation. CONCLUSION: Total distribution of bronchial artery supply to the human lung has been visualized in lung transplant patients. This study demonstrates that this nutritive flow reaches even the most peripheral parts of the lungs and is present 1 mo as well as 2 y after lung transplantation. The results suggest that bronchial artery revascularization may be of significance for the long-term status of the lung transplant.     

Radionuclide pulmonary arteriography

Radionuclide pulmonary arteriography offers a unique method for visualizing the main pulmonary artery and its major branches. Since the radioactive particles that are injected intravenously become lodged in the pulmonary capillaries and pre-capillary arterioles, there is no interference from the systemic circulation. Normally, the main pulmonary artery is visualized for no longer than 4 or 6 seconds; prolongation of the duration of visualization may be indicative of, for example, pulmonary hypertension and pulmonary embolism. The patency of the left and right pulmonary arteries may be determined and sites of occlusion identified.     

Chronic multiple pulmonary emboli. Regional response of the bronchial circulation

In pulmonary embolism, the bronchial circulation can dramatically increase perfusion to the lung and prevent infarction. The physiology of this response is incompletely understood. The authors studied the regional changes in the bronchial circulation in an animal model after multiple chronic pulmonary emboli to the periphery of one lung. The gross anatomy of the bronchial circulation was studied using Batson's solution to produce vascular casts of the pulmonary and bronchial circulations. These casts were prepared in a normal sheep and in a sheep with multiple chronic microemboli in the periphery of one lung. The normal bronchial arteries are visible as threadlike structures covering the surface of the tracheobronchial tree with ramifications extending to the lung periphery. In a sheep with multiple chronic microemboli, the bronchial arteries supply the pulmonary parenchyma deprived of pulmonary arterial flow. The bronchial arteries following pulmonary arterial embolization markedly dilate and are serpentine.     

Effects of venous return on respiratory response.

This study reevaluated the link between the rate of CO2 flow to the pulmonary circulation and changes in cardiac output to the respiratory responses following leg lifting in normal man subjects. Thirty healthy subjects (mean age = 22.2 years) were subjected to the experimental maneuver which increased venous return to the right heart. Cardiac output was significantly increased and with it a significant increase in CO2 output by the lungs was found. These results were associated with a significant increase in expired ventilation. The rapidity of the ventilatory response to the increase in cardiac output suggests the existence of pressoreceptors localized in the pulmonary circulation which, when activated, results in the elicitation of respiratory reflexes. The end result is an adjustment in the respiratory response in accordance with venous return.     

CT evaluation of chronic thromboembolic pulmonary hypertension.

Eight patients with chronic thromboembolic pulmonary hypertension (CTPH) that had been demonstrated by perfusion lung scan, pulmonary arteriography, and right heart catheterization had their pulmonary circulation evaluated by CT. Eight subjects without lung pathology were also studied for comparison. High resolution CT from apex to base with 1 cm thick sections after intravenous injection of contrast medium was performed in each individual. Emboli lodged in main pulmonary arteries on arteriography were regularly shown by CT, whereas those in segmental or smaller arteries were not detected. Diameters of the main pulmonary arteries measured on CT correlated with systolic pulmonary artery pressure (p < 0.001). The ratio between diameters of segmental arteries and the corresponding bronchi (A/B ratio) on CT was > 1 in 72 of 144 examined pulmonary segments (18 segments for each patient) in patients with CTPH. The ratio was > 1 in only 10 of 144 examined segments in normal control subjects. Dilatation of bronchial arteries was present in four of eight patients with CTPH. The parenchymal density in patients with CTPH was significantly higher in the axial than in the middle or peripheral lung compartments. In conclusion, CT may help with the diagnosis of CTPH by detecting thrombi of main arteries and by showing characteristic findings; moreover, it is accurate in estimating pulmonary arterial pressure secondary to thromboembolic obstruction.     

Sudden infant death attributed to peracute pulmonary infection: two autopsy cases

This report describes two autopsy cases of sudden infant death attributed to peracute pulmonary infection in which possible causative microorganisms could be identified despite only minor pathological findings. Both babies were 5-month-old boys, who had no symptomatic disorders and were found dead in bed. Their main macropathology was inflated heavy lungs with patchy bleedings. One case showed a pulmonary histopathological finding suggestive of viral infection, and adenovirus DNA was detected from the intrabronchial fluid. In the second case, pulmonary histopathology was a feature of early inflammatory reaction involving focal necrosis with some neutrophil infiltration and many intra-alveolar macrophages containing gram-positive cocci, and Staphylococcus aureus was identified in venous blood culture. These findings significantly support the presence of pathogenic microorganisms in sudden infant death.     

Polyarteritis nodosa and hepatitis-B surface antigen: role of angiography in diagnosis.

two patients with polyarteritis nodosa who presented with vague constitutional systems and hepatitis-B antigenemia are reported. Angiography was used as the primary diagnostic procedure and confirmed the diagnosis in each case. Angiography is a relatively simple and direct means for establishing the diagnosis of polyarteritis nodosa. In these patients, the typical finding of aneurysm formation in multiple organs was observed. Arterial narrowing was also widespread. Multiple renal infarcts are shown in one case, and bronchial arteriography revealed aneurysms and narrowing in bronchial and intercostal arteries in one patient who had a recent pulmonary infarction and a normal pulmonary arteriogram. The relationship of the hepatitis-B antigen and polyarteritis is also emphasized.     

活动性肺结核肺间质病变的HRCT研究

目的 探讨活动性肺结核肺间质改变的HRCT表现.资料与方法 搜集肺部CT扫描以间质改变为主的活动性肺结核29例,分别在治疗前、治疗中和疗程结束时行HRCT检查,分析间质改变的影像特点及变化.结果 肺结核间质病变好发于两上肺野,主要表现为片状蔓延和沿支气管树分布两种形式.小叶内间质异常是肺结核间质改变的主要HRCT表现,包括小叶内细网织线影、微结节、磨玻璃影、树芽征等,其发生率分别为100%(29例)、100%(29例)、82.8%(24例)、69%(20例).此外可合并气道壁增厚、融合性实变、空洞、结节等征象.经抗结核治疗后间质病变吸收较缓慢,但在疗程结束时均大部分吸收.结论 小叶内细网织线影、微结节、磨玻璃影、树芽征为活动性肺结核间质的主要HRCT表现.     

Bronchial circulation angiogenesis in the rat quantified with SPECT and micro-CT

INTRODUCTION: As pulmonary artery obstruction results in proliferation of the bronchial circulation in a variety of species, we investigated this angiogenic response using single photon emission computed tomography (SPECT) and micro-CT. MATERIALS AND METHODS: After surgical ligation of the left pulmonary artery of rats, they were imaged at 10, 20, or 40 days post-ligation. Before imaging, technetium-labeled macroaggregated albumin ((99m)Tc MAA) was injected into the aortic arch (IA) labeling the systemic circulation. SPECT/micro-CT imaging was performed, the image volumes were registered, and activity in the left lung via the bronchial circulation was used as a marker of bronchial blood flow. To calibrate and to verify successful ligation, (99m)Tc MAA was subsequently injected into the left femoral vein (IV), resulting in accumulation within the pulmonary circulation. The rats were reimaged, and the ratio of the IA to the IV measurements reflected the fraction of cardiac output (CO) to the left lung via the bronchial circulation. Control and sham-operated rats were studied similarly. RESULTS: The left lung bronchial circulation of the control group was 2.5% of CO. The sham-operated rats showed no significant difference from the control. However, 20 and 40 days post-ligation, the bronchial circulation blood flow had increased to 7.9 and 13.9%, respectively, of CO. Excised lungs examined after barium filling of the systemic vasculature confirmed neovascularization as evidenced by tortuous vessels arising from the mediastinum and bronchial circulation. CONCLUSION: Thus, we conclude that SPECT/micro-CT imaging is a valuable methodology for monitoring angiogenesis in the lung and, potentially, for evaluating the effects of pro- or anti-angiogenic treatments using a similar approach.     

Intrathoracic extracardiac shunts

The source of pulmonary collateral circulation varies according to the nature, location and duration of the inciting pathological process. Bronchial, intercostal, internal mammary, brachiocephalic and other arteries that arise in the mediastinum from the aorta or its branches are the major source of pulmonary arterial collateral circulation. The bronchial veins and mediastinal veins are interconnected with the azygos, vertebral, mediastinal, and thoracic wall veins. They constitute the major venous pathways of the collateral circulation. Anomalous arteries and veins may be recognized radiologically as the cause of a variety of intrathoracic, extracardiac shunts.     

Angiography of a bronchial carcinoid tumour.

The author describes a patient in whom a bronchial carcinoid tumour was demonstrated preoperatively only by bronchial arteriography. The reported arteriographic characteristics of such a lesion include hypertrophy of the bronchial artery, a tumour blush and the apparent absence of venous drainage.     

The effect of acute pulmonary edema on pulmonary vascular resistance: significance for the interpretation of dilated upper lobe vessels on chest radiographs

Dilation of upper lobe pulmonary vessels is an important radiographic sign of acute, left heart failure. A prominent theory is that perivascular edema causes increased resistance at the lung bases and inverts the normal perfusion gradient such that upper lobe blood flow exceeds lower lobe flow. This theoretical increase in flow is thought to cause dilatation of upper lobe vessels. Previous experimental studies determined indirectly changes in resistance from changes in the perfusion gradient: Results were contradictory. We measured directly the effect of edema on resistance in isolated canine lungs. Resistance increased linearly with edema. The magnitude of increase was small, however, and insufficient to cause inversion of the perfusion gradient. Our data indicate that interstitial pulmonary edema does not cause significant redistribution of blood flow. We suggest that dilated upper lobe vessels are veins acting as pulmonary venous manometers, reflecting elevated left atrial pressure, not increased blood flow.     

Systemic arterial supply to the lungs in adults: spiral CT findings.

Systemic arterial supply to the lungs can be congenital or due to acquired disease. Congenital diseases encompass bronchopulmonary sequestration and congenital pulmonary venolobar syndrome, in which the involved lung parenchyma is supplied by the aberrant systemic arteries. An anomalous systemic artery can also supply an area of otherwise normal lung parenchyma. In acquired diseases, hypertrophied normal systemic arteries supply the lungs. Hypertrophied systemic arteries include the bronchial arteries, intercostal arteries, internal mammary arteries, inferior phrenic arteries, branches of the thyrocervical trunk, branches of the hepatic arteries, and branches of the abdominal aorta. Hypertrophy of normal systemic arteries is encountered in patients with bronchiectasis, pulmonary tuberculosis, other pulmonary infections, pulmonary thromboembolism, or chronic obstructive pulmonary disease. These systemic arteries are considered to supply the lungs by means of anastomoses between bronchial and pulmonary arteries within the lung parenchyma or transpleural systemic-pulmonary artery anastomoses. In most cases, the correct diagnosis and treatment plan can be determined by identification of the systemic arteries on computed tomographic scans.     

Assessment of major aortopulmonary collateral arteries with multidetector-row computed tomography

Multidetector-row computed tomography (MDCT) studies were performed in three adult patients with pulmonary atresia with a ventricular septal defect. In all patients, the native pulmonary arteries were absent, and the pulmonary circulation was totally supplied by major aortopulmonary collateral arteries (MAPCAs). MDCT studies with 1-mm collimation provided detailed information on MAPCAs and bronchial collaterals, such as the numbers and sites of origin, their varying diameters, their courses, and the areas of the lungs they supply. MDCT studies may provide an efficient road map for safe and successful selective catheterization and may substitute for conventional angiography in patients with considerable risks.     

Paradoxical embolization via a patent foramen ovale following acute pulmonary embolism

The foramen ovale is usually obliterated following establishment of the adult circulation but remains patent in 25% of individuals. This potential communication between the venous and arterial circulations can allow thromboembolic material to bypass the lungs and enter the systemic circulation. We report two cases of paradoxical embolization through a patent foramen ovale following acute large pulmonary embolism (PE) and discuss the factors that predispose to paradoxical embolization following PE.     

支气管动脉栓塞治疗肺大咯血

目的　探讨支气管动脉栓塞治疗大咯血的方法及疗效。方法　对 36例大咯血或长期反复咯血的病人用明胶海绵颗粒栓塞支气管动脉。 36例病人中 ,单侧 31例 ,双侧 5例。肺癌 1 7例 ,支气管扩张 8例 ,肺结核 1 1例。先行支气管动脉造影 ,确定出血血管后 ,用明胶海绵颗粒栓塞 ,直到支气管动脉闭塞为止。结果　即刻止血 31例 ,出血完全控制。 5例咯血明显减少 ,内科治疗后咯血完全停止。随访 3月～ 5年 ,再出血 2例。结论　支气管动脉栓塞是治疗大咯血的有效方法 ,效果确切 ,止血迅速