DOI: 10.1148/rg.261045726
RadioGraphics 2006;26:3-22
© RSNA, 2006
Multi–Detector Row CT of Hemoptysis1
John F. Bruzzi, FFRRCSI,
Martine Rémy-Jardin, MD,
Damien Delhaye, MD,
Antoine Teisseire, MD,
Chadi Khalil, MD and
Jacques Rémy, MD
1 From the Department of Radiology, Hospital Calmette, University Center of Lille, Blvd Jules Leclercq, 59037 Lille, France. Received December 15, 2004; revision requested April 13, 2005 and received June 2; accepted June 3. All authors have no financial relationships to disclose.
Address correspondence to M.R. (e-mail: mremy-jardin{at}chru-lille.fr).
 |
Abstract
|
|---|
Hemoptysis is symptomatic of a potentially life-threatening condition and warrants urgent and comprehensive evaluation of the lung parenchyma, airways, and thoracic vasculature. Multi–detector row computed tomographic (CT) angiography is a very useful noninvasive imaging modality for initial assessment of hemoptysis. The combined use of thin-section axial scans and more complex reformatted images allows clear depiction of the origins and trajectories of abnormally dilated systemic arteries that may be the source of hemorrhage and that may require embolization. Conditions such as bronchiectasis, chronic bronchitis, lung malignancy, tuberculosis, and chronic fungal infection are some of the most common underlying causes of hemoptysis and are easily detected with CT. "Cryptogenic" hemoptysis is common among smokers and warrants subsequent follow-up imaging to exclude possible underlying malignancy. The bronchial arteries are the source of bleeding in most cases of hemoptysis. Contributions from the non-bronchial systemic arterial system represent an important cause of recurrent hemoptysis following apparently successful bronchial artery embolization. Vascular anomalies such as pulmonary arteriovenous malformations and bronchial artery aneurysms are other important causes of hemoptysis. Multi–detector row CT angiography permits noninvasive, rapid, and accurate assessment of the cause and consequences of hemorrhage into the airways and helps guide subsequent management.
© RSNA, 2006
|
LEARNING OBJECTIVES FOR TEST 1
|
|---|
After reading this article and taking the test, the reader will be able to:
- Discuss the pathophysiologic features and the most important direct causes of hemoptysis.
- Describe the complex anatomy and varied imaging appearances of the bronchial and non-bronchial systemic arteries.
- Enumerate the essential principles of thoracic CT angiography performed prior to embolization therapy for massive hemoptysis.
|
Introduction
|
|---|
Hemoptysis, defined as bleeding that originates from the lower respiratory tract (1), is symptomatic of potentially serious or even life-threatening thoracic disease and warrants urgent investigation. The immediate risk posed by hemoptysis is airway compromise; thus, assessment of the clinical significance of an episode of hemoptysis should take into account not only the volume of expectorated blood but also the effects on the patient’s respiratory and cardiovascular reserves. The aim of initial diagnostic evaluation should be to identify the immediate source and importance of bleeding, but the assessment is not complete without a thorough inquiry into the underlying primary cause of the hemoptysis. Standard diagnostic algorithms have been based on combinations of conventional radiography, rigid or fiberoptic bronchoscopy, chest computed tomography (CT), and thoracic aortography (2). Recent important technologic advances in CT, particularly the development of multi–detector row CT, have introduced a comprehensive, noninvasive method of evaluating the entire thorax, allowing detailed assessment of the mediastinum and lung parenchyma. At the same time, these technologic advances allow high-resolution angiographic studies of the thoracic and upper abdominal vasculature, which are useful prior to anticipated bronchial artery embolization or surgical intervention (3,4). CT findings can also direct the endoscopist toward bronchial or parenchymal abnormalities and signal possible dangers such as peribronchial or endoluminal aneurysms. There have been few reports on the use of multi–detector row CT in the assessment of hemoptysis; most published experience has been based on single–detector row spiral CT technology (5–8).
In this article, we review the pathophysiologic features and causes of hemoptysis, describe the bronchial and nonbronchial systemic arterial anatomy, and discuss the initial evaluation of acute hemoptysis. We also discuss and illustrate the role of multi–detector row CT in hemoptysis with regard to its exquisite diagnostic capabilities and its potential influence on management decision making.
|
Pathophysiologic Features and Causes of Hemoptysis
|
|---|
The lungs are supplied by a dual arterial vascular system composed of (a) the pulmonary arteries, which account for 99% of the arterial blood supply to the lungs and take part in gas exchange; and (b) the bronchial arteries, which are responsible for providing nourishment to the supporting structures of the airways and of the pulmonary arteries themselves (vasa vasorum) but do not normally take part in gas exchange (9). The bronchial vasculature feeding the intrapulmonary airways is situated close to the pulmonary arteries at the level of the vasa vasorum, and histologically the two systems are connected by anastomoses between the systemic and pulmonary capillaries (10). This communication between the bronchial and pulmonary arteries contributes to a normal right-to-left shunt that accounts for 5% of cardiac output (11).
In certain situations, the thin-walled capillary communications between the high-pressure systemic bronchial arterial system and the lower-pressure pulmonary arterial system can vasodilate and enlarge. Conditions causing reduced pulmonary arterial perfusion such as chronic thrombo-embolic disease and vasculitic disorders, in which there is a reduction in pulmonary arterial supply distal to the emboli, can lead to a gradual increase in the bronchial arterial contribution (6,12–15), thereby increasing the importance of bronchial-to-pulmonary artery anastomoses in regions of the lung that are deprived of their pulmonary arterial blood flow. Experimental studies have suggested that the increased bronchial arterial blood flow is due to neovascularization (12). The anastomotic vessels, which are subjected to increased systemic arterial pressure, are often thin walled and prone to rupture into the alveoli or bronchial airways, giving rise to hemoptysis.
Chronic inflammation can also lead to an increase in systemic arterial blood flow (16,17). Chronic inflammatory disorders such as bronchiectasis, chronic bronchitis, and chronic necrotizing infections (in particular, tuberculosis and mycotic lung disease) are associated with the release of angiogenetic growth factors such as vascular endothelial growth factor and angiopoietin 1, leading to neovascularization and vascular remodeling as well as an increase in the collateral supply from nearby systemic vessels (18,19). Such newly formed collateral vessels are usually fragile and "leaky" and prone to rupture. Neoplastic disease can also be responsible for such humor-mediated neovascularization.
On angiographic studies, systemic vessels responsible for an abnormal collateral blood supply to the lungs in episodes of hemoptysis appear as dilated, usually tortuous arteries with associated parenchymal staining by contrast material, systemic-to-pulmonary arterial shunting, and, rarely, contrast material extravasation at the points of bleeding (20–22). The bronchial arteries are implicated in the majority of cases. On occasion, bleeding may occur from nonbronchial systemic arteries or from the pulmonary arteries themselves.
The most common underlying causes of hemoptysis vary in reported studies depending on the geographic location of the study, the prevalence of tuberculosis, and the use of cross-sectional imaging (2). In most reports, bronchiectasis, chronic bronchitis, tuberculosis, and malignancy are the most important causes (2,23–26). These, along with less common causes, are listed in Table 1. "Cryptogenic" hemoptysis, for which no cause can be identified, is responsible for 3.0%–42.2% of episodes of hemoptysis (2,31, 32), particularly in smokers, but is a diagnosis of exclusion and might be expected to decrease in prevalence with more systematic use of CT.
|
Systemic Arterial Blood Supply to the Lungs
|
|---|
In over 90% of cases of hemoptysis requiring intervention with arterial embolization or surgery, the bronchial arteries are responsible for the bleeding (3). Bronchial arterial anatomy has been well described but is highly variable. In over 70% of the general population, the bronchial arteries arise from the descending thoracic aorta, most commonly between the levels of T5 and T6. There are normally one or two bronchial arteries supplying each lung, arising either independently or from a common trunk (33,34). On the right side, an intercostobronchial trunk usually exists, arising from the right posteromedial aspect of the aorta and coursing cranially before giving rise to one or more posterior intercostal arteries and a right bronchial arterial component. This component turns sharply in the caudal direction to the level of the right main bronchus, where it ramifies in the lung parenchyma parallel to the bronchus and more distal airways. The left bronchial artery usually arises from the anterior aspect of the descending thoracic aorta, either singly (30.5% of cases) or as a common trunk with a second right bronchial artery (25%), before coursing sinuously toward the left hilum and perhaps through the aortopulmonary window (22). In 70% of cases, there are two left bronchial arteries in addition to the right intercostobronchial trunk (33). Because of its short mediastinal course, the left bronchial artery may be difficult to see clearly at single–detector row CT (5).
Bronchial arteries that arise in the expected location from the descending thoracic aorta between the levels of T5 and T6 are called orthotopic bronchial arteries. Anomalous bronchial arteries, defined as bronchial arteries that originate outside the T5 through T6 range, are found in 8.3%–21% of cases of hemoptysis (4,35). This anomalous artery arises from the concavity of the aortic arch in most cases (14.7% of cadavers in a study by Cauldwell et al [33]), but it may less commonly originate from the lower thoracic aorta, subclavian arteries, thyrocervical trunk, costocervical trunk, brachiocephalic artery, internal mammary artery, pericardiophrenic artery, or inferior phrenic artery (3,4,33,35,36).
Bronchial arteries can be distinguished from nonbronchial systemic arteries in that their trajectory into the pulmonary parenchyma parallels the bronchovascular axes. In contrast, nonbronchial systemic collateral vessels do not run parallel to the airways and have a more unpredictable origin from infradiaphragmatic arteries or from the supraaortic great vessels or their branches. The most commonly implicated arteries include the inferior phrenic arteries, the musculophrenic and pericardiodiaphragmatic branches of the internal thoracic arteries, the posterior intercostal arteries, and branches from the thyrocervical trunk (3,8, 17,25). These arteries provide systemic collateral vessels that reach the lung parenchyma via the inferior pulmonary ligaments (in the case of the inferior phrenic arteries) or transpleural adhesions (in the case of branches from the intercostal and supraaortic arteries) and that form anastomoses with the pulmonary arterial circulation in regions of inflammation or neoplasia.
|
Initial Evaluation of Acute Hemoptysis
|
|---|
The severity and natural course of hemoptysis are difficult to predict clinically. The initial evaluation of patients who present with acute hemoptysis includes estimation of the volume of expectorated blood and assessment of cardiorespiratory stability. Certain authors have attempted to discriminate between "major" and "massive" hemoptysis, and various definitions of severity have been proposed, ranging from 100 mL to 1 L of blood expectorated in 24 hours (24,37,38). Although the mortality rate rises as the volume of hemoptysis increases (2,24), any assessment of the severity of hemoptysis must take into account the patient’s cardiorespiratory status, bleeding activity, the possibility of "internalized" (eg, intrapleural, intrapericardial, or intracavitary) bleeding, and the risk of recurrent bleeding. In particular, the recognition of "sentinel bleeding" heralding imminent major hemorrhage is of critical importance but is often difficult on the basis of clinical findings alone (39,40).
Bronchoscopy, performed with either a rigid or a flexible fiberoptic endoscope, is useful in diagnosing active hemorrhage and in controlling the airway in patients with catastrophic hemorrhage (23). However, it is less useful in detecting underlying disease, and its capacity to help localize the site of bleeding is equivalent to that of radiography or CT (24,41). The airways are often filled with blood at the time of bronchoscopy, making evaluation of the distal airways difficult. Furthermore, irritation of the bronchial mucosa caused by lavage or by the endoscope itself can lead to recurrent bleeding. Certain advantages of bronchoscopy such as hemorrhage control with infusion of iced saline solution, balloon inflation, or yttrium aluminum garnet laser coagulation are of unproved efficacy and depend on the practitioner’s skills (23,42). In addition, biopsy of perceived endoluminal abnormalities performed at the time of bronchoscopy can have unforeseen consequences when the vascular nature of such anomalies is not recognized (43,44).
Radiography can help lateralize the bleeding with a high degree of certainty and can often help detect underlying parenchymal and pleural abnormalities (41). Although radiography is a useful initial examination, it needs to be complemented with more detailed evaluation. In a study by Herth et al (45), almost one-quarter of patients presenting with acute hemoptysis secondary to malignancy had normal chest radiographic findings. The authors recommended additional follow-up testing in patients presenting with hemoptysis in whom the underlying cause was not detected at initial radiography.
Contrast material–enhanced multi–detector row CT has the unparalleled advantage of allowing acquisition of high-quality images of the entire thorax in a rapid, safe, and noninvasive manner. Published studies on the efficacy of single–detector row spiral CT have already demonstrated the capacity of this imaging technique to help predict the site of bleeding as accurately as bronchoscopy and to help detect underlying disease with high sensitivity (2,24). Multi–detector row CT provides extended volume coverage with higher image resolution and even greater scanning speed (46,47). The aims of multi–detector row CT in the evaluation of hemoptysis are threefold: (a) to depict underlying disease with high sensitivity by means of detailed images of the lung parenchyma and mediastinum, and in particular to help detect early carcinoma; (b) to help assess the consequences of hemorrhage into the alveoli and airways, which may cause immediate clinical concerns as well as mask subtle underlying abnormalities; and (c) to provide a detailed "road map" of the thoracic vasculature by means of two-dimensional (2D) maximum-intensity-projection (MIP) reformatted images and three-dimensional (3D) reconstructed images. Such road maps are of great use to both the interventional radiologist anticipating arterial embolization and the thoracic surgeon contemplating surgery.
|
Multi–Detector Row CT Technique
|
|---|
An extended spiral CT study of the thorax can easily be performed with a 16–detector row scanner during a single breath hold (normally lasting less than 15 seconds) in most patients. However, only a limited study with a four–detector row or single–detector row scanner may be possible, depending on the patient’s respiratory capacity. Image acquisition should be performed in a cranio-caudal direction from the base of the neck to the level of the renal arteries to include the supraaortic great vessels and the infradiaphragmatic arteries, which may be responsible for an abnormal collateral contribution to the lungs.
With current multi–detector row systems, optimal enhancement of both the pulmonary and systemic arteries is achieved with the injection of approximately 120 mL of a relatively high-density contrast material (350 mg/dL) at a rate of 4 mL/sec via an 18-gauge cannula into an antecubital vein or central venous catheter. The scan should be started during the phase of peak systemic arterial enhancement (Table 2). Images should be acquired with thin collimation and with the table movement adjusted to allow extended volume coverage during a single breath hold. By adjusting the exposure parameters and kilovoltage according to the patient’s weight, the radiation dose to the patient can be minimized without compromising image quality. In certain cases, it may be useful or even necessary to perform follow-up CT several months after the episode of hemoptysis to study the evolution of underlying parenchymal lung abnormalities or to exclude the possibility that a small malignancy may have been missed at initial CT. Repeat evaluation of the bronchial arteries is not usually necessary unless there is continued hemoptysis; consequently, follow-up imaging can be performed without intravenously administered contrast material and at low milli-amperage to minimize the radiation dose to the patient, which is of particular importance in young patients. Automatic dose modulation at the level of the thoracic inlet is not recommended, so as to avoid streak artifact from osseous structures and from high-density contrast material within the great veins.
|
Data Manipulation and Image Interpretation
|
|---|
Because of the very large number of images acquired with a thin-collimation scan of the extended thorax, studies are best interpreted at the scanner console or remote workstation by scrolling through the images.
The lung parenchyma and gross soft-tissue structures can be adequately evaluated with a section thickness of 5 mm. Detailed analysis of the airways and lung interstitium requires thinner sections.
Thoracic CT angiography with a combination of multiplanar reformatted images can help identify the variable origins and courses of arteries that may be responsible for bleeding in cases of hemoptysis and can aid in planning the embolization of these arteries. The origins of orthotopic mediastinal bronchial arteries are best depicted on overlapping axial thin-section images (eg, 1-mm-thick sections at 0.75-mm increments) (Fig 1a). Two-dimensional MIP reformatted images in the coronal oblique and sagittal planes readily depict the tortuous trajectories of the bronchial arteries from their origins (descending thoracic aorta) to the lungs along the main bronchi (Fig 1b, 1c); reformatted images in straight coronal planes are better suited for analysis of the intercostal and internal mammary arteries; and axial reconstructed images are ideal for demonstrating the inferior phrenic arteries and branches from the celiac axis. The degree of obliquity of the reconstruction planes and the section thickness of the reformatted images normally have to be adjusted on a case-by-case basis to provide optimal depiction of the vessels in question.
View larger version (113K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1a. Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (a) Axial 1-mm-thick CT scan obtained just below the aortic arch (window center, 50 HU; window width, 350 HU) shows enlarged bronchial arteries (arrow) manifesting as avidly enhancing nodules in the paratracheal and retrobronchial regions of the mediastinum. These findings represent the typical appearance of enlarged bronchial arteries on axial images. Although the origins of the bronchial arteries are well depicted on axial images, their further course is very tortuous, and the intrapulmonary direction of the artery can be difficult to ascertain. (b) Coronal thin-section MIP image clearly demonstrates an enlarged intercostobronchial artery (arrows) coursing into the pulmonary parenchyma parallel to the bronchial airways. (c) Coronal thin-section MIP image obtained in a different patient provides a detailed analysis of the entire intrapulmonary course of an intercosto-bronchial artery (arrows).  = intracavitary mycetoma. (d) Reformatted image demonstrates how CT angiography can provide anatomic information that is useful for planning subsequent bronchial artery embolization.
|
|
View larger version (147K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1b. Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (a) Axial 1-mm-thick CT scan obtained just below the aortic arch (window center, 50 HU; window width, 350 HU) shows enlarged bronchial arteries (arrow) manifesting as avidly enhancing nodules in the paratracheal and retrobronchial regions of the mediastinum. These findings represent the typical appearance of enlarged bronchial arteries on axial images. Although the origins of the bronchial arteries are well depicted on axial images, their further course is very tortuous, and the intrapulmonary direction of the artery can be difficult to ascertain. (b) Coronal thin-section MIP image clearly demonstrates an enlarged intercostobronchial artery (arrows) coursing into the pulmonary parenchyma parallel to the bronchial airways. (c) Coronal thin-section MIP image obtained in a different patient provides a detailed analysis of the entire intrapulmonary course of an intercosto-bronchial artery (arrows). = intracavitary mycetoma. (d) Reformatted image demonstrates how CT angiography can provide anatomic information that is useful for planning subsequent bronchial artery embolization.
|
|
View larger version (162K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1c. Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (a) Axial 1-mm-thick CT scan obtained just below the aortic arch (window center, 50 HU; window width, 350 HU) shows enlarged bronchial arteries (arrow) manifesting as avidly enhancing nodules in the paratracheal and retrobronchial regions of the mediastinum. These findings represent the typical appearance of enlarged bronchial arteries on axial images. Although the origins of the bronchial arteries are well depicted on axial images, their further course is very tortuous, and the intrapulmonary direction of the artery can be difficult to ascertain. (b) Coronal thin-section MIP image clearly demonstrates an enlarged intercostobronchial artery (arrows) coursing into the pulmonary parenchyma parallel to the bronchial airways. (c) Coronal thin-section MIP image obtained in a different patient provides a detailed analysis of the entire intrapulmonary course of an intercosto-bronchial artery (arrows). = intracavitary mycetoma. (d) Reformatted image demonstrates how CT angiography can provide anatomic information that is useful for planning subsequent bronchial artery embolization.
|
|
View larger version (148K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1d. Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (a) Axial 1-mm-thick CT scan obtained just below the aortic arch (window center, 50 HU; window width, 350 HU) shows enlarged bronchial arteries (arrow) manifesting as avidly enhancing nodules in the paratracheal and retrobronchial regions of the mediastinum. These findings represent the typical appearance of enlarged bronchial arteries on axial images. Although the origins of the bronchial arteries are well depicted on axial images, their further course is very tortuous, and the intrapulmonary direction of the artery can be difficult to ascertain. (b) Coronal thin-section MIP image clearly demonstrates an enlarged intercostobronchial artery (arrows) coursing into the pulmonary parenchyma parallel to the bronchial airways. (c) Coronal thin-section MIP image obtained in a different patient provides a detailed analysis of the entire intrapulmonary course of an intercosto-bronchial artery (arrows). = intracavitary mycetoma. (d) Reformatted image demonstrates how CT angiography can provide anatomic information that is useful for planning subsequent bronchial artery embolization.
|
|
Three-dimensional volumetric and shaded-surface-display (SSD) reformatted images are useful not only to interventional radiologists contemplating embolization therapy (Fig 1d), for whom they provide a better perspective on the origin and course of the abnormal artery and aid in the choice of catheter shape, but also to surgeons anticipating arterial ligation, particularly when "minithoracotomy" techniques are used. In addition to depicting the abnormal vessel itself and its relationship to adjacent anatomic structures, volumetric reformatted images can furnish the surgeon with a "preview" of the osseocartilaginous and musculotendinous structures that will be involved in any planned surgical intervention.
In summary, a comprehensive range of reconstructed images that includes thick- and thin-section axial images obtained with both mediastinal soft-tissue and parenchymal lung window settings, as well as 2D MIP reformatted images in the coronal, sagittal, and axial planes and selected 3D volumetric and SSD reformatted images, are recommended for a thorough CT assessment of hemoptysis (Table 3).
|
Assessment of the Lung Parenchyma
|
|---|
Urgent evaluation with thoracic CT angiography can help accurately identify the source and predisposing causes of hemoptysis and the effects of hemorrhage on the lungs. Possible underlying causes of hemoptysis that are identifiable on axial CT scans obtained with lung parenchymal window settings include bronchiectasis (Fig 2), lung carcinoma, acute and chronic lung infections (in particular, tuberculosis and aspergillosis), and cardiogenic pulmonary edema (22–24,41,45,48). In patients with extensive bilateral disease or equivalent findings, the site of hemorrhage can usually be localized on the basis of the presence of liquified material in segmental and lobar bronchi and hazy consolidation or ground-glass infiltrates in the lung parenchyma, findings that represent intraalveolar hemorrhage. The accurate localization of the site of bleeding is important both for possible future lung resection and prior to endovascular therapy, for which identification of the specific vessels that require embolization is necessary.
View larger version (140K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2a. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
View larger version (164K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2b. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
View larger version (151K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2c. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
View larger version (127K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2d. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
View larger version (136K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2e. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
View larger version (114K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2f. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
View larger version (120K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2g. Bronchiectasis in a 51-year-old man who presented with recurrent hemoptysis. (a) Posteroanterior chest radiograph demonstrates severe cystic bronchiectasis in the middle lobe and lingula. (b–g) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) demonstrates severe cystic bronchiectasis in the right middle lobe and in the lower divisions of the left upper lobe (lingula). (c–g) Thin-section MIP images obtained in the sagittal (c), axial (d), and coronal (e, f ) planes and a 3D volumetric reformatted image (g) depict markedly dilated and tortuous bronchial arteries (arrows in c) and hypertrophic right and left inferior phrenic arteries (arrows in d–g) arising from the abdominal aorta and supplying the areas of bronchiectasis.
|
|
The consequences of hemorrhage into the airways and lung parenchyma may also mask subtle underlying disease. The filling of airway lumina or intraparenchymal cavities with blood (Fig 3) may obscure small endobronchial tumors and intracavitary lesions such as mycetomas. In addition, blood clots may simulate more sinister disease entities such as nodules and masses (49). For these reasons, it is often advisable to perform follow-up CT several weeks after the episode of hemoptysis for a more thorough analysis of the underlying lung parenchyma and for the detection of early lung carcinoma.
View larger version (138K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3a. (a) Axial CT scan (1-mm-thick section) obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) in a patient with hemorrhage following an episode of hemoptysis demonstrates bronchial impaction from blood clot (arrow) in a subsegmental branch of the anterior segmental bronchus of the right upper lobe, a finding that helps localize the site of bleeding. (b) Axial CT scan (1-mm-thick section) (window center, –600 HU; window width, 1600 HU) obtained at the level of the right lower lobe in a patient with lymphangioleiomyomatosis who presented with recurrent hemoptysis depicts an air-fluid level in a pulmonary cyst (arrow), a finding that represents intracavitary blood. The consequences of hemoptysis in the lung parenchyma can obscure subtle underlying lesions such as intrabronchial tumors, and follow-up CT performed several weeks after the acute episode is always recommended.
|
|
View larger version (154K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3b. (a) Axial CT scan (1-mm-thick section) obtained with parenchymal lung window settings (window center, –600 HU; window width, 1600 HU) in a patient with hemorrhage following an episode of hemoptysis demonstrates bronchial impaction from blood clot (arrow) in a subsegmental branch of the anterior segmental bronchus of the right upper lobe, a finding that helps localize the site of bleeding. (b) Axial CT scan (1-mm-thick section) (window center, –600 HU; window width, 1600 HU) obtained at the level of the right lower lobe in a patient with lymphangioleiomyomatosis who presented with recurrent hemoptysis depicts an air-fluid level in a pulmonary cyst (arrow), a finding that represents intracavitary blood. The consequences of hemoptysis in the lung parenchyma can obscure subtle underlying lesions such as intrabronchial tumors, and follow-up CT performed several weeks after the acute episode is always recommended.
|
|
|
Assessment of Pulmonary and Systemic Vasculature
|
|---|
Pulmonary Arteries
Assessment of the thoracic vasculature in cases of hemoptysis should always include the pulmonary arterial circulation and the bronchial and non-bronchial systemic arteries. The pulmonary arteries should always be analyzed to exclude the possibility of pulmonary emboli, particularly in the presence of subpleural areas of enhancement that could represent areas of lung infarction and that may be responsible for hemoptysis. Acute thromboembolic disease is a frequent cause of nonmassive hemoptysis that requires urgent diagnosis and treatment with anticoagulation therapy. The pulmonary arteries may also be the source of hemorrhage in cases of direct invasion by neoplastic disease or by necrotizing inflammatory disorders such as tuberculosis (50). Rasmussen aneurysms, representing fragile pulmonary arterial pseudoaneurysms arising within areas of tuberculous inflammation, may be responsible for sentinel bleeding prior to catastrophic hemorrhage and can be identified on contrast-enhanced CT scans as avidly enhancing nodules located within the walls of tuberculous cavities (51–53).
Dieulafoy disease is a poorly understood condition characterized by abnormally dilated submucosal vessels that are prone to hemorrhage and has been described in the colon, the small intestine, and, more recently, the bronchial airways. It usually coexists with chronic inflammatory disorders such as chronic bronchitis and is thought to involve the pulmonary arterial system rather than the bronchial arteries (54,55). At fiberoscopic endoscopy, the visualization of a tangle of dilated submucosal blood vessels in the presence of mucosal inflammation should raise suspicion for Dieulafoy disease and alert the bronchoscopist to forego mucosal biopsy (43,44). To our knowledge, there have been no published CT descriptions of this vascular anomaly.
Life-threatening hemoptysis may occur, albeit uncommonly, following rupture of thin-walled pulmonary arteriovenous malformations (30,56). Pulmonary arteriovenous malformations with feeding arteries larger than 3 mm can be successfully treated with coil embolization therapy.
Bronchial Arteries
In 95% of cases of hemoptysis, the systemic arterial system is the origin of the bleeding (3). The value of bronchial artery embolization for the treatment of massive hemoptysis has been well described (20,21,57,58). Although there is poor correlation between bronchial arterial dilatation and the risk of hemorrhage (49), a diameter of more than 2 mm is considered abnormal (22) and, when arterial embolotherapy is being considered, usually indicates the vessel to be embolized. The bronchial arteries have highly tortuous but predictable trajectories that can easily be analyzed with a thorough knowledge of bronchial arterial anatomy (33). Because they course predominantly perpendicular to the scanning plane, on axial images they appear as a cluster of avidly enhancing nodules in the posterior mediastinum, usually just below the level of the aortic arch (22).
Although the bronchial arteries are the most common source of bleeding in hemoptysis, the actual hemorrhage usually occurs from fragile thin-walled anastomoses between distant bronchial arterial branches and pulmonary arteries that are under high systemic arterial pressure, located in the airway submucosa and too small to be directly visualized at CT. Active bleeding can rarely be detected at CT due to the presence of contrast material in the airway lumen (Fig 4). At conventional angiography, active hemorrhage can also manifest as staining of the lung parenchyma by contrast material (58).
View larger version (141K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4a. Hemorrhage from the intercostobronchial trunk in a 64-year-old man with hemoptysis of 400 mL in 24 hours. (a) Posteroanterior chest radiograph obtained at the time of admission demonstrates no abnormality. (b, c) Axial thoracic CT scans obtained on a 16–detector row scanner with lung parenchymal window settings (window center, –600 HU; window width, 1600 HU) (b) and mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) (c) depict dense material (arrow) within the apical segmental bronchus of the right upper lobe. (d–f ) Sequential arteriograms of the intercostobronchial artery demonstrate immediate filling of the apical segmental bronchus with contrast material (arrow in e and f), a finding that indicates active bleeding from the intercostobronchial trunk into the bronchial tree. Embolization of this artery was successfully performed, with immediate cessation of hemoptysis.
|
|
View larger version (106K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4b. Hemorrhage from the intercostobronchial trunk in a 64-year-old man with hemoptysis of 400 mL in 24 hours. (a) Posteroanterior chest radiograph obtained at the time of admission demonstrates no abnormality. (b, c) Axial thoracic CT scans obtained on a 16–detector row scanner with lung parenchymal window settings (window center, –600 HU; window width, 1600 HU) (b) and mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) (c) depict dense material (arrow) within the apical segmental bronchus of the right upper lobe. (d–f ) Sequential arteriograms of the intercostobronchial artery demonstrate immediate filling of the apical segmental bronchus with contrast material (arrow in e and f), a finding that indicates active bleeding from the intercostobronchial trunk into the bronchial tree. Embolization of this artery was successfully performed, with immediate cessation of hemoptysis.
|
|
View larger version (54K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4c. Hemorrhage from the intercostobronchial trunk in a 64-year-old man with hemoptysis of 400 mL in 24 hours. (a) Posteroanterior chest radiograph obtained at the time of admission demonstrates no abnormality. (b, c) Axial thoracic CT scans obtained on a 16–detector row scanner with lung parenchymal window settings (window center, –600 HU; window width, 1600 HU) (b) and mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) (c) depict dense material (arrow) within the apical segmental bronchus of the right upper lobe. (d–f ) Sequential arteriograms of the intercostobronchial artery demonstrate immediate filling of the apical segmental bronchus with contrast material (arrow in e and f), a finding that indicates active bleeding from the intercostobronchial trunk into the bronchial tree. Embolization of this artery was successfully performed, with immediate cessation of hemoptysis.
|
|
View larger version (97K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4d. Hemorrhage from the intercostobronchial trunk in a 64-year-old man with hemoptysis of 400 mL in 24 hours. (a) Posteroanterior chest radiograph obtained at the time of admission demonstrates no abnormality. (b, c) Axial thoracic CT scans obtained on a 16–detector row scanner with lung parenchymal window settings (window center, –600 HU; window width, 1600 HU) (b) and mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) (c) depict dense material (arrow) within the apical segmental bronchus of the right upper lobe. (d–f ) Sequential arteriograms of the intercostobronchial artery demonstrate immediate filling of the apical segmental bronchus with contrast material (arrow in e and f), a finding that indicates active bleeding from the intercostobronchial trunk into the bronchial tree. Embolization of this artery was successfully performed, with immediate cessation of hemoptysis.
|
|
View larger version (113K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4e. Hemorrhage from the intercostobronchial trunk in a 64-year-old man with hemoptysis of 400 mL in 24 hours. (a) Posteroanterior chest radiograph obtained at the time of admission demonstrates no abnormality. (b, c) Axial thoracic CT scans obtained on a 16–detector row scanner with lung parenchymal window settings (window center, –600 HU; window width, 1600 HU) (b) and mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) (c) depict dense material (arrow) within the apical segmental bronchus of the right upper lobe. (d–f ) Sequential arteriograms of the intercostobronchial artery demonstrate immediate filling of the apical segmental bronchus with contrast material (arrow in e and f), a finding that indicates active bleeding from the intercostobronchial trunk into the bronchial tree. Embolization of this artery was successfully performed, with immediate cessation of hemoptysis.
|
|
View larger version (124K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4f. Hemorrhage from the intercostobronchial trunk in a 64-year-old man with hemoptysis of 400 mL in 24 hours. (a) Posteroanterior chest radiograph obtained at the time of admission demonstrates no abnormality. (b, c) Axial thoracic CT scans obtained on a 16–detector row scanner with lung parenchymal window settings (window center, –600 HU; window width, 1600 HU) (b) and mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) (c) depict dense material (arrow) within the apical segmental bronchus of the right upper lobe. (d–f ) Sequential arteriograms of the intercostobronchial artery demonstrate immediate filling of the apical segmental bronchus with contrast material (arrow in e and f), a finding that indicates active bleeding from the intercostobronchial trunk into the bronchial tree. Embolization of this artery was successfully performed, with immediate cessation of hemoptysis.
|
|
Bronchial artery aneurysms are rare entities that may arise either within the mediastinum or from the intrapulmonary portion of the artery (28). Whereas intrapulmonary bronchial artery aneurysms may remain clinically silent, mediastinal aneurysms can manifest with symptoms related to local compressive effects (59). Rupture of intrapulmonary aneurysms gives rise to massive and often catastrophic hemoptysis (28); rupture of more proximal mediastinal aneurysms may manifest with acute tearing chest pain simulating aortic dissection (60). Bronchial artery aneurysms can be detected with contrast-enhanced CT (Fig 5) (61,62). The success of coil embolization therapy depends on aneurysm location; attempts at embolization of aneurysms arising close to the ostia of the bronchial artery can be limited by difficulty in coil placement (61).
View larger version (157K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5a. Bronchial artery aneurysm in a 37-year-old man with acute hemoptysis of 300 mL in 24 hours. (a) Posteroanterior chest radiograph demonstrates a cavitating mass in the right upper lobe, a finding that subsequently proved to be cavitating reactivation tuberculosis. (b–d) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan (1-mm-thick section) obtained with mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) depicts a dense nodular lesion (white arrow) within a necrotic mass in the right upper lobe. Enlarged bronchial arteries (black arrows) can be identified in the mediastinum. (c, d) On thin-section (3-mm) axial (c) and coronal (d) MIP images, the dense nodule (arrow) can be clearly identified as a bronchial artery aneurysm within the necrotic mass. Note the adjacent nodular calcifications in the wall of the mass. (e) Arteriogram shows the aneurysm (arrow) arising from a branch of the intercosto-bronchial artery, which was later successfully embolized.
|
|
View larger version (87K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5b. Bronchial artery aneurysm in a 37-year-old man with acute hemoptysis of 300 mL in 24 hours. (a) Posteroanterior chest radiograph demonstrates a cavitating mass in the right upper lobe, a finding that subsequently proved to be cavitating reactivation tuberculosis. (b–d) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan (1-mm-thick section) obtained with mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) depicts a dense nodular lesion (white arrow) within a necrotic mass in the right upper lobe. Enlarged bronchial arteries (black arrows) can be identified in the mediastinum. (c, d) On thin-section (3-mm) axial (c) and coronal (d) MIP images, the dense nodule (arrow) can be clearly identified as a bronchial artery aneurysm within the necrotic mass. Note the adjacent nodular calcifications in the wall of the mass. (e) Arteriogram shows the aneurysm (arrow) arising from a branch of the intercosto-bronchial artery, which was later successfully embolized.
|
|
View larger version (97K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5c. Bronchial artery aneurysm in a 37-year-old man with acute hemoptysis of 300 mL in 24 hours. (a) Posteroanterior chest radiograph demonstrates a cavitating mass in the right upper lobe, a finding that subsequently proved to be cavitating reactivation tuberculosis. (b–d) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan (1-mm-thick section) obtained with mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) depicts a dense nodular lesion (white arrow) within a necrotic mass in the right upper lobe. Enlarged bronchial arteries (black arrows) can be identified in the mediastinum. (c, d) On thin-section (3-mm) axial (c) and coronal (d) MIP images, the dense nodule (arrow) can be clearly identified as a bronchial artery aneurysm within the necrotic mass. Note the adjacent nodular calcifications in the wall of the mass. (e) Arteriogram shows the aneurysm (arrow) arising from a branch of the intercosto-bronchial artery, which was later successfully embolized.
|
|
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5d. Bronchial artery aneurysm in a 37-year-old man with acute hemoptysis of 300 mL in 24 hours. (a) Posteroanterior chest radiograph demonstrates a cavitating mass in the right upper lobe, a finding that subsequently proved to be cavitating reactivation tuberculosis. (b–d) Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (b) Axial CT scan (1-mm-thick section) obtained with mediastinal soft-tissue window settings (window center, 50 HU; window width, 350 HU) depicts a dense nodular lesion (white arrow) within a necrotic mass in the right upper lobe. Enlarged bronchial arteries (black arrows) can be identified in the mediastinum. (c, d) On thin-section (3-mm) axial (c) and coronal (d) MIP images, the dense nodule (arrow) can be clearly identified as a bronchial artery aneurysm within the necrotic mass. Note the adjacent nodular calcifications in the wall of the mass. (e) Arteriogram shows the aneurysm (arrow) arising from a branch of the intercosto-bronchial artery, which was later successfully embolized.
|
|
Top
Abstract
LEARNING OBJECTIVES FOR TEST...
