HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lee, E. Y. Articles by Cleveland, R. H. Search for Related Content PubMed PubMed Citation Articles by Lee, E. Y. Articles by Cleveland, R. H.

Multidetector CT Evaluation of Congenital Lung Anomalies¹

¹ From the Departments of Radiology (E.Y.L., R.H.C.) and Medicine, Pulmonary Division (E.Y.L.), Children's Hospital Boston and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115; and Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass (P.M.B.). Received December 12, 2006; revision requested February 7, 2007; revision received February 17; accepted March 20; final version accepted June 1; final review and update by E.Y.L. January 11, 2008. E.Y.L. supported in part by a GE-AUR Research Award, the Society of Thoracic Radiology Research Grant, and the Society for Pediatric Radiology Research Fellow Grant. Address correspondence to E.Y.L. (e-mail: Edward.Lee{at}childrens.harvard.edu).

	ABSTRACT

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Congenital lung anomalies vary widely in their clinical manifestation and imaging appearance. Although radiographs play a role in the incidental detection and initial imaging evaluation in patients with clinical suspicion of congenital lung anomalies, cross-sectional imaging such as computer tomography (CT) is frequently required for confirmation of diagnosis, further characterization, and preoperative evaluation in the case of surgical lesions. Recently, with the development and widespread availability of multidetector CT scanners, CT has assumed a greater role in the noninvasive evaluation of congenital lung anomalies. The combination of fast speed, high spatial resolution, and enhanced quality of multiplanar reformation and three-dimensional reconstructions makes multidetector CT an ideal noninvasive method for evaluating congenital lung anomalies. In this article, the authors review the multidetector CT technique for evaluation of congenital lung anomalies. Important clinical aspects, characteristic imaging features, and key points that allow differentiation among various anomalies are highlighted for a variety of common and uncommon conditions.

© RSNA, 2008

	INTRODUCTION

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Congenital lung anomalies vary widely in their clinical manifestation and imaging appearance. Although radiographs play a role in the incidental detection and initial imaging evaluation in patients with clinical suspicion of congenital lung anomalies, cross-sectional imaging such as computer tomography (CT) is frequently required for confirmation of diagnosis, further characterization, and preoperative evaluation in the case of surgical lesions. Recently, with the development and widespread availability of multidetector CT scanners, CT has assumed a greater role in the noninvasive evaluation of congenital lung anomalies. The combination of fast speed, high spatial resolution, and enhanced quality of multiplanar reformation (MPR) and three-dimensional (3D) reconstructions makes multidetector CT an ideal noninvasive method for evaluating congenital lung anomalies.

In this article, the authors review the multidetector CT technique for evaluation of congenital lung anomalies. Important clinical aspects, characteristic imaging features, and key points that allow differentiation among various anomalies are highlighted for a variety of common and uncommon conditions.

	TECHNIQUE

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Patient Preparation
Sedation for pediatric patients.—Sedation is generally not required during CT examination for older children and adults. However, it is still generally necessary for infants and children who are younger than 5 years of age or who are unable to cooperate with breath holding or lying still. However, the frequency with which sedation is employed for younger children has decreased with multidetector CT owing to its fast CT scanning times. Conscious sedation is nearly always used for CT examinations in young children (1). With conscious sedation, patients can maintain a patent airway independently and continuously and respond appropriately to physical stimulation and/or verbal commands with a minimally depressed level of consciousness. The most commonly used sedative drugs for infants and young children are oral chloral hydrate and intravenous pentobarbital sodium. Maintaining safe cardiorespiratory support is paramount for proper pediatric patient care during and after CT examination (2–5).

Intravenous contrast material.—In evaluating vascular structures associated with congenital lung anomalies in children, intravenous contrast material is typically administered to the pediatric patient, who may experience agitation from the venipuncture. In cases where intravenous contrast material must be administered, intravenous access should ideally be in place when the child arrives in the radiology department, thus minimizing any anxiety that may arise from the procedure (5).

In current practice, nonionic low-osmolar contrast material is widely used to minimize discomfort at the injection site as well as side effects, such as nausea and vomiting (4,5). The usual recommended contrast material dose is 2 mL per kilogram of patient body weight (not to exceed 4 mL/kg or 125 mL) (4,5). Although contrast material may be administered by means of manual injection, mechanical injection is the preferred method, especially for CT angiography. Mechanical injection of contrast material provides homogeneous contrast enhancement within the vessels, which is particularly helpful for 3D reconstruction of vascular structures.

For mechanical administration of the contrast material, a 22-gauge or larger cannula should be placed into an antecubital vein. Contrast material is infused at 1.5–2.5 mL/sec for a 22-gauge catheter and 2.0–4.0 mL/sec for a 20-gauge catheter (5). For infants or small children who have a smaller than 22-gauge catheter or central venous line in place, the contrast medium should be administered by means of manual injection (5). The injection site should be closely monitored during the initial injection to minimize the risk of contrast material extravasation (5).

Multidetector CT Technical Considerations
Although technical parameters vary somewhat based on the type of multidetector CT scanner and the specific protocol used to answer a particular clinical question, accurate CT evaluation of congenital lung anomalies rests on certain basic principles, which are reviewed in the following paragraphs.

Multidetector CT parameters.—To obtain an optimal CT data set, as well as to enhance the quality of MPR and 3D reconstruction images, multidetector CT parameters must be selected properly in advance. These parameters include: tube current or milliamperage, kilovoltage peak, table speed, detector collimation, and reconstruction thickness (4,5). Moreover, the amount of radiation exposure must be carefully assessed, a particularly important consideration in pediatric patients. The milliamperage for pediatric CT examinations should be at the lowest possible level while also maintaining diagnostic image quality (4–9). Guidelines for tube current based on patient weight are shown in Table 1 (4,5). Kilovoltage also affects scan quality and radiation dose. A kilovoltage peak of 80 should be used for patients who weigh less than 50 kg. In larger children or adult patients, a kilovoltage peak of 100–120 is needed to compensate for the higher noise (5,10). Fast scan times (fast table speed) of 1 second or less should be used. Detector collimation and table speed will vary depending on the type of multidetector CT scanner used. However, in general, 1.0–1.5-mm collimation with a pitch of 1.5–2.0 is adequate for routine scanning for a four–detector row scanner. For an eight– to 16–detector row scanner, 0.625–1.0-mm collimation with a pitch of 1.0–2.0 can be used. For a 64–detector row scanner, 0.5–0.6-mm collimation and a pitch of 1.0–1.5 will suffice (4,5). For 3D reconstruction, the volumetric data are reconstructed with 3-mm section thickness at a 2-mm reconstruction interval or with 2-mm section thickness at a 1-mm reconstruction interval, with the goal of obtaining approximately 50% of overlap, which will improve lesion conspicuity (4,5,11–13). An exception is when very thin collimation (0.5–1.0 mm) is employed. Such thin collimation results in an isotropic data set, in which spatial resolution is the same regardless of whether images are reviewed in the transverse, sagittal, or coronal plane (14).

Postprocessing Techniques
With the advent of multidetector CT and its ability to produce high-quality thin-section CT images, recently developed postprocessing methods, including MPR and 3D volume rendering, are now routinely used to evaluate congenital lung anomalies.

Multiplanar reconstruction.—Multiplanar images are 1-voxel-thick CT images that use all pixels in the data set regardless of CT attenuation (4,5). Multiplanar volume reformation images comprise a thick slab of adjacent thin sections and represent a block of contiguous images. The thickness of such blocks or slabs varies but usually ranges from 3 to 10 mm. Multiplanar volume reformation images thus combine the spatial resolution of MPR images with the anatomic display of thicker sections. Multiplanar images can be created along any selected planes such as coronal, sagittal, orthogonal, and curved planes (4,5). Compared with other imaging reconstruction techniques, one of the most beneficial advantages of MPR is that it requires virtually no reconstruction time and can be easily performed at the CT console or two-dimensional or 3D imaging workstation. The disadvantage of MPR is that it is only a two-dimensional image, lacking "depth" information.

Three-dimensional volume rendering.—The volume-rendering technique is currently the most widely used 3D reconstruction method for evaluating intrathoracic vascular and airway structures. In contrast to transverse or MPR CT images, the volume rendering technique uses the entire attenuation composition as well as the spatial relationships in the initial raw CT data set (5). With this postprocessing volume rendering technique, the initial CT data can be reconstructed based on different widths, opacity, brightness, and color (4,5). Such postprocessing allows the initial CT data to be displayed in three dimensions from an external or internal perspective of the vascular and airway structures.

	THE SPECTRUM OF CONGENITAL LUNG ANOMALIES

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Similar to other congenital anomalies, the imaging appearance of congenital lung anomalies varies widely (Fig 1). Although congenital lung anomalies can manifest as unique entities such as a pure lung parenchymal abnormality (eg, CCAM) or as a pure vascular abnormality (eg, pulmonary AVM), they can also manifest as a combination of parenchymal and vascular abnormalities (17). Occasionally, more than one entity can coexist and appear as a mixed lesion, such as CCAM and sequestration. For evaluating congenital lung anomalies at CT, anomalies may be divided into three categories: nonvascular lesions (ie, abnormal lung and normal vasculature), vascular lesions (ie, normal lung and abnormal vasculature), or a combination of both (ie, abnormal lung and abnormal vasculature).

View larger version (9K): [in this window] [in a new window] [Download PPT slide]   Figure 1: Spectrum of congenital lung anomalies shows a pure lung parenchyma abnormality, such as a congenital cystic adenomatoid malformation (CCAM), and a pure vascular abnormality, such as a pulmonary arteriovenous malformation (AVM). Congenital lung anomalies can also manifest as a combination of parenchymal and vascular abnormalities such as sequestration and scimitar syndrome. (Adapted and reprinted, with permission, from reference 17.)

	NONVASCULAR LESIONS

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

CT imaging features.—The characteristic CT feature of congenital bronchial atresia is a central masslike opacity that may have a tubular configuration (Fig 2) or may contain an air-fluid level representing the obstructed, dilated, and mucoid-filled segmental or subsegmental bronchus. It is typically located in the apical or apicoposterior segment of the upper lobes (18,19). Hyperinflation due to collateral air drift and a relative paucity of vessels owing to obstructed or absent vascular supply in the involved segment of lung are other commonly associated CT findings. CT is the best imaging modality for confirming bronchial atresia suspected on chest radiographs because it allows excellent visualization of the mucoid impaction within the dilated bronchus, associated segmental hypoattenuation, and decreased vascularity.

View larger version (142K): [in this window] [in a new window] [Download PPT slide]   Figure 2: Transverse CT image in 1-year-old boy with known right lower lobe nodular lesion, representing mucus accumulation within the patent bronchus distal to the atretic segment, shows characteristic CT appearance of a congenital bronchial atresia manifested as a round opacity (arrow) associated with an area of hypoattenuation (arrowheads) and decreased vascularity. Note its somewhat atypical location, since congenital bronchial atresia is typically located in the apical or apicoposterior segment of the upper lobes.

Bronchogenic Cysts
Key clinical aspects.—Bronchogenic cysts are developmental lesions resulting from abnormal ventral budding or branching of the tracheobronchial tree, which occurs between the 26th and 40th days of gestation (20–22). Bronchogenic cysts are part of the family of foregut duplication cysts consisting of bronchogenic cysts, enteric cysts, and neurenteric cysts. A definitive diagnosis of bronchogenic cyst is made when respiratory epithelium is histologically present (22). Bronchogenic cysts typically occur in the middle mediastinum in the paratracheal, carinal, and hilar regions in 65%–90% of cases (21–23). The subcarinal location is most common, followed by the right paratracheal region. However, less commonly, bronchogenic cysts can also manifest as pulmonary lesions, with the majority located within the lower lobes (21,24). When bronchogenic cysts are small, affected patients are usually asymptomatic; however, when the lesions are large enough to apply substantial mass effect on adjacent mediastinal structures such as the central airways and esophagus (21,22,24), a variety of symptoms may occur, including chest pain, respiratory distress, and dysphagia. Treatment options include observation, resection, and aspiration. For symptomatic patients, the treatment choice is generally surgical resection (21–25).

CT imaging features.—Bronchogenic cysts are characteristically well-circumscribed round or ovoid solitary lesions with uniform fluid attenuation on CT images (0–20 HU) (22–24) (Fig 3). Although 50% of bronchogenic cysts show water attenuation on CT images, the degree of CT attenuation of bronchogenic cysts depends on the amount of internal proteinaceous content. CT with intravenous contrast material administration is helpful in differentiating bronchogenic cysts from other possible vascular abnormalities. With intravenous contrast material, a nonenhancing or minimally enhancing thin wall is typically seen. Thick enhancing walls, solid components, calcifications, or septations are not commonly seen in bronchogenic cysts, although a cyst wall may calcify (23). When bronchogenic cysts result in substantial mass effect on adjacent airways, hyperinflation or lung collapse may occur. Further, when the cysts are infected, interval increases in size, as well as internal air-fluid level or enhancing wall thickening, can be seen at CT. On chest radiographs, bronchogenic cysts typically manifest as a well-defined middle mediastinal mass that is difficult to differentiate from lymphadenopathy. Hence, CT is particularly helpful in confirming the diagnosis of bronchogenic cysts and for evaluating their anatomic relationship with other mediastinal or parenchymal structures for preoperative planning.

View larger version (93K): [in this window] [in a new window] [Download PPT slide]   Figure 3: Transverse contrast-enhanced CT image in 2-year-old girl with possible right hilar mass on chest radiographs. Image demonstrates a round cystic lesion (arrow) in the right subcarinal and azygoesophageal recess region, with mild mass effect on adjacent right main bronchus and right main pulmonary artery. There is no internal enhancing solid component, calcification, or septations. Surgical pathologic finding was consistent with a broncogenic cyst.

Congenital Lobar Emphysema
Key clinical aspects.—Congenital lobar emphysema (CLE) is also known as infantile lobar emphysema or congenital lobar hyperinflation. The classically described form of CLE may be the result of progressive overdistension of a pulmonary lobe, associated with either intrinsic or extrinsic obstructions, as well as deficient bronchial cartilage (21,24,26–30). This form of CLE has a normal or decreased number of alveoli that are overdistended. There are more alveoli than expected in a more recently described polyalveolar form (31). Although any lobe can be affected, there is a lobar predilection (left upper lobe > right middle lobe > right upper lobe > lower lobes) (26). Occasionally, only a portion of lobe or more than one lobe may be involved. Patients with CLE usually present during the neonatal period and infancy with respiratory distress, especially when there is marked hyperinflation in the involved lobe and mass effect on adjacent lung parenchyma or mediastinum (24). Surgical lobectomy is indicated, particularly in patients with progressive hyperinflation of CLE, which can be life threatening (24,27,29,30). These patients typically have an excellent prognosis after surgical resection (30).

CT imaging features.—CLE may initially appear as an opacity on radiographs owing to accentuated retention of fetal lung fluid just after birth. However, as fetal lung fluid is cleared by means of lymphatic resorption and replaced by air, the affected lobe generally shows hyperlucency with mass effect on the adjacent, nonaffected lobes (26) (Fig 4a). On CT images, a hyperinflated lobe with attenuating and displaced pulmonary vessels is typically seen (Fig 4b). Mediastinal shift to the contralateral side and separated ribs, as well as a depressed diaphragm on the ipsilateral side, can be also seen when the lesion is large and has mass effect on adjacent structures (26). CT is useful for diagnosis of multilobar involvement and mass effect on the remaining adjacent ipsilateral lung and mediastinal structures.

View larger version (146K): [in this window] [in a new window] [Download PPT slide]   Figure 4a: (a) Frontal chest radiograph in 2-year-old boy with mild nonspecific respiratory distress shows subtle hyperlucency in right upper lung. The patient was subsequently further evaluated at CT. (b) Coronal MPR CT lung window image depicts hyperinflated right upper lobe with attenuating and displaced pulmonary vessels. At surgical resection, a diagnosis of CLE was confirmed. Also note mild mass effect on the adjacent right middle lobe.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 4b: (a) Frontal chest radiograph in 2-year-old boy with mild nonspecific respiratory distress shows subtle hyperlucency in right upper lung. The patient was subsequently further evaluated at CT. (b) Coronal MPR CT lung window image depicts hyperinflated right upper lobe with attenuating and displaced pulmonary vessels. At surgical resection, a diagnosis of CLE was confirmed. Also note mild mass effect on the adjacent right middle lobe.

Congenital Cystic Adenomatoid Malformation
Key clinical aspects.—CCAM is a congenital lung mass of unknown cause resulting from disorganized hamartomatous and adenomatoid proliferation of primary bronchioles, which are in communication with the bronchial tree (21,24,26,32–37). There are three types of CCAM, which have different radiologic appearances, gross pathologic findings, and histologic findings, as described by Stocker et al (36). The most common subtype is a type 1 CCAM, in which there is at least one dominant cyst that is larger than 2 cm in size. Type 2 CCAM has numerous small cysts of uniform size measuring 1–10 mm in diameter. Type 3 CCAM, the least common, appears solid at imaging; however, at histologic evaluation, it is characterized by numerous microcysts. Patients with CCAM usually present with symptoms such as respiratory distress during the newborn period or infancy, as well as with recurrent infection (21,24,26). However, CCAM can also be incidentally detected in asymptomatic older pediatric patients. Symptomatic CCAM is routinely treated by means of surgical resection, which is usually curative (24,34). Prognosis, however, depends on the size of the lesion, the degree to which the remaining lung is underdeveloped, and the presence of other associated congenital anomalies (24,26,33–35). Type 2 and type 3 CCAM are frequently associated with other congenital anomalies, resulting in a less favorable prognosis than is generally seen with type 1 CCAM. Although the management of asymptomatic CCAM is somewhat unclear, elective surgical resection is sometimes recommended because there is a risk of infection, as well as a low risk of malignancy.

CT imaging features.—CCAM demonstrates a variety of imaging appearances based on the type of CCAM and the presence or absence of associated superimposed infection (21,24,26,37). Type 1 CCAM usually demonstrates one or more large, air-filled cystic structures with possible internal air-fluid levels (Fig 5). The typical appearance of type 2 CCAM is an air-filled multicystic mass or focal area of consolidation (Figs 6, 7). Type 3 CCAM appears solid at imaging owing to microscopic cysts (<2 mm in diameter) that can be identified only at histologic evaluation. An internal air-fluid level and enhancing thick wall can be seen in patients with infected CCAM (21,24,26,37). CT is useful in the identification and characterization of CCAMs; in evaluating mass effect on adjacent structures; and in distinguishing CCAM from other congenital lung anomalies, particularly from sequestration. While there is no systemic arterial supply in CCAM, sequestration is characterized by an anomalous systemic arterial supply that can be clearly visualized with CT angiography. Although rarely seen, a cystic form (type 1) of pleuropulmonary blastoma can manifest as a cystic lung lesion similar in imaging appearance to CCAM (37,38) (Fig 8). CCAM, particularly when it is located in the lower lobes, can be confused with congenital diaphragmatic hernia, which is characterized by herniated bowel loops located in the lower thoracic cavity. In this situation, CT with coronal and sagittal reconstructions can aid in evaluating the diaphragm, thus enabling the radiologist to distinguish CCAM from congenital diaphragmatic hernia.

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 5: Transverse CT lung window image in 6-week-old girl shows type 1 CCAM (arrow) manifesting as a single cystic lung lesion in the left lower lobe. Mild attenuation representing air trapping adjacent to the left lower lobe CCAM is also seen.

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 6: Transverse CT lung window image in 5-week-old boy with prenatal diagnosis of right side chest mass shows type 2 CCAM manifesting as multiple small cystic lesions within the right lower lobe.

View larger version (102K): [in this window] [in a new window] [Download PPT slide]   Figure 7: Sagittal 3D volume-rendered image in 1-day-old boy with prenatal diagnosis of a complex right middle lobe mass depicts extensive type 2 CCAM. The 3D volume-rendered image improved the delineation of the extent of CCAM compared with the transverse CT images and was helpful for preoperative evaluation.

View larger version (128K): [in this window] [in a new window] [Download PPT slide]   Figure 8: Coronal CT lung window image in 2-month-old boy with shortness of breath and abnormal chest radiographs shows a large cystic lesion with several internal septations and mildly thick walls in the right lung with associated mediastinal shift to left side. Although this lesion was initially interpreted as a CCAM, it was later found to be a rare cystic type of pleuropulmonary blastoma.

	ANOMALIES OF PULMONARY ARTERY

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Proximal Interruption of the Pulmonary Artery
Key clinical aspects.—In this congenital anomaly, the proximal portion of the main pulmonary artery (arising from the primitive sixth aortic arch) fails to appear during embryologic development (21,39–41). Although the affected lung is hypoplastic due to insufficient growth, the bronchial anatomy, including the number of lobes and segments, is normal. Pulmonary vessels on the contralateral side are commonly enlarged, and vascular supply to the affected lung is accomplished via systemic collateral vessels—mainly through multiple, enlarged aortopulmonary collateral arteries. Pulmonary venous return is usually normal. Although the proximal interruption of the pulmonary artery can affect either the right or left pulmonary artery, it typically occurs on the right, which is the opposite side of the normal left aortic arch (39). However, when this condition occurs on the left, on the ipsilateral side to the normal left aortic arch, it is often associated with congenital heart disease such as tetralogy of Fallot, right aortic arch, patent ductus arteriosus, and septal defects (39). Although a majority of cases are diagnosed and treated in infancy, in some patients this condition can manifest later in life, with symptoms such as recurrent pulmonary infection and, less commonly, hemoptysis resulting from systemic to pulmonary arterial shunting (42). In patients with massive hemoptysis at presentation, urgent embolization of systemic collateral vessels is indicated.

CT imaging features.—The affected pulmonary artery terminates within 1 cm of its origin from the main pulmonary artery (18,39). The lung on the affected side is hypoplastic and is associated with mediastinal shift to the ipsilateral side (Fig 9a). The pulmonary artery on the contralateral side is enlarged. Multiple aortopulmonary collateral arteries supply the lung on the affected side. CT angiography with 3D reconstructions is particularly helpful in evaluating the affected pulmonary artery, the enlarged contralateral side pulmonary artery, and multiple collateral vessel formation (18,39) (Fig 9b). CT can also be used to demonstrate lung parenchymal changes such as bronchiectasis, which sometimes manifests within the affected lung.

View larger version (110K): [in this window] [in a new window] [Download PPT slide]   Figure 9a: (a) Transverse contrast-enhanced CT image shows proximal interruption of right pulmonary artery (large arrow) in 57-year-old woman presenting with shortness of breath. CT was subsequently performed for evaluation of possible pulmonary embolism. Right lung is hypoplastic and associated with mediastinal shift to the right side. Enlarged left pulmonary artery (LP) and bronchial artery collateral vessels (small arrows) are also noted. (b) Posterior view of 3D volume-rendered image demonstrates markedly enlarged left pulmonary artery (LP). Multiple aortopulmonary collateral arteries supplying right lung (arrows) arising from the aorta (A) are also noted.

View larger version (114K): [in this window] [in a new window] [Download PPT slide]   Figure 9b: (a) Transverse contrast-enhanced CT image shows proximal interruption of right pulmonary artery (large arrow) in 57-year-old woman presenting with shortness of breath. CT was subsequently performed for evaluation of possible pulmonary embolism. Right lung is hypoplastic and associated with mediastinal shift to the right side. Enlarged left pulmonary artery (LP) and bronchial artery collateral vessels (small arrows) are also noted. (b) Posterior view of 3D volume-rendered image demonstrates markedly enlarged left pulmonary artery (LP). Multiple aortopulmonary collateral arteries supplying right lung (arrows) arising from the aorta (A) are also noted.

Pulmonary Artery Sling
Key clinical aspects.—Pulmonary artery sling, also known as anomalous origin of the left pulmonary artery, is a condition in which the left main pulmonary artery arises from the proximal right main pulmonary artery and courses to the left hemithorax (21,39). As the anomalous left pulmonary artery crosses to the left hemithorax, it courses between the trachea and esophagus, resulting in a "sling" around the distal trachea (43–51). Embryologically, a pulmonary artery sling occurs when there is an agenesis or obliteration of the primitive left sixth aortic arch, which typically forms the left main pulmonary artery (18). There are two types of pulmonary artery slings (43,49,51). In a type 1 pulmonary artery sling, the carina is normally located at the T4 through T5 vertebral levels and there is a characteristic compression of the posterior aspect of the trachea, right main stem bronchus, and anterior aspect of the esophagus. In a type 2 pulmonary artery sling, the carina is low in location, at the T6 level, and is associated with congenital long-segment tracheal stenosis, a horizontal course of the main bronchi (ie, T-shaped carina), a bridging bronchus, and several other congenital anomalies (43,49,51). Patients with pulmonary artery sling typically present during the neonatal period with respiratory symptoms such as stridor, apneic spells, and hypoxia (43–50). Symptomatic patients are treated with surgical division and reimplantation of the anomalous left pulmonary artery to main pulmonary artery (48,50). In patients with associated tracheal anomaly in a type 2 pulmonary artery sling, tracheobronchial reconstruction is also performed.

CT imaging features.—Imaging findings of pulmonary artery sling depend on its type, as well as on other associated congenital anomalies (43,45,46,49). In a type 1 pulmonary artery sling, characteristic posterior compression of the trachea and anterior compression of esophagus is caused by the anomalous left pulmonary artery coursing between the trachea and esophagus (43) (Fig 10). Because of the compression of the right main stem bronchus, hyperinflation of the right lung can be also seen. By contrast, type 2 pulmonary artery sling is associated with tracheal stenosis, trachea bifurcation at the T6 level into bridging right and left mainstem bronchus (ie, T-shaped carina), and other congenital anomalies such as hypoplasia or agenesis of right lung, a horseshoe lung, and congenital heart diseases (4,5,43,49,51). Although pulmonary artery sling has been evaluated historically with various radiologic and nonradiologic studies including chest radiography, barium swallow study, catheter pulmonary angiography, bronchoscopy, and echocardiography, most of these studies have been replaced by multidetector CT with 3D reconstructions (39,44,51). Anomalous left pulmonary artery with associated central airway compression and anomalies are accurately assessed and diagnosed with multidetector CT and 3D reconstructions. In addition, dynamic airway CT performed during inspiration and expiration is helpful for differentiating between tracheal stenosis and tracheomalacia in patients with pulmonary artery sling.

View larger version (67K): [in this window] [in a new window] [Download PPT slide]   Figure 10: Transverse contrast-enhanced CT image in 9-year-old girl with known pulmonary artery sling and intermittent respiratory distress shows an anomalous origin of the left pulmonary artery (ie, pulmonary artery sling). Anomalous left pulmonary artery (arrow) arises from the right pulmonary artery (RA) and courses to the left hemithorax behind the carina (C).

Pulmonary Agenesis
Key clinical aspects.—Pulmonary agenesis is a rare congenital malformation of unknown cause in which there is a complete absence of a lung, including its bronchi and vascular supply (18,26,52–60). This disorder occurs on either side with almost equal frequency (61). In contrast to bilateral agenesis of the lung, which is uniformly fatal, unilateral pulmonary agenesis is compatible with life (62). However, affected patients, particularly infants, have a high mortality rate because of other associated congenital anomalies, including congenital heart disease, tracheoesophageal atresia, spinal anomalies, and renal anomalies (54,57–59,61). Patients with unilateral pulmonary agenesis typically present in the neonatal period with nonspecific respiratory symptoms such as cyanosis, tachypnea, stridor, or feeding difficulties (52–62). In asymptomatic older children and adults, unilateral lung agenesis can be an incidental finding.

CT imaging features.—The characteristic imaging appearance of pulmonary agenesis on frontal chest radiographs is an opacified hemithorax associated with a marked ipsilateral mediastinal shift (26,52,48,53,60). Typically, the lateral chest radiograph shows evidence of hyperlucency in the anterior chest because a portion of the hyperinflated contralateral lung is herniated anteriorly across the midline. Osseous structures of the affected side can be hypoplastic. CT is helpful for diagnosing the absence of a lung, including its bronchi and vascular supply (52,60) (Fig 11). Other associated anomalies, such as congenital heart disease and spinal anomalies, can also be evaluated with CT.

View larger version (67K): [in this window] [in a new window] [Download PPT slide]   Figure 11a: (a) Transverse contrast-enhanced CT image in 16-year-old girl with known Gardner syndrome and intermittent shortness of breath shows absent right lung and marked mediastinal shift to the right hemithorax. An enlarged, hyperinflated left lung crossing the mediastinum anteriorly is noted. T = trachea. (b) Coronal MPR CT image again demonstrates right lung agenesis associated with mediastinal shift to the right side. Also note hypoplastic osseous structures of the right hemithorax.

View larger version (97K): [in this window] [in a new window] [Download PPT slide]   Figure 11b: (a) Transverse contrast-enhanced CT image in 16-year-old girl with known Gardner syndrome and intermittent shortness of breath shows absent right lung and marked mediastinal shift to the right hemithorax. An enlarged, hyperinflated left lung crossing the mediastinum anteriorly is noted. T = trachea. (b) Coronal MPR CT image again demonstrates right lung agenesis associated with mediastinal shift to the right side. Also note hypoplastic osseous structures of the right hemithorax.

	ANOMALIES OF PULMONARY VEINS

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Pulmonary Vein Stenosis
Key clinical aspects.—Congenital pulmonary vein stenosis is a condition in which there is uncontrolled growth of myofibroblast-like connective tissue cells that results in the thickening and narrowing of the pulmonary vein (39). This condition usually occurs in association with other congenital anomalies, such as congenital heart disease and partial or total anomalous pulmonary venous return (39). However, it can also occur in infants who do not have other congenital anomalies. In these cases, pulmonary vein stenosis frequently progresses rapidly, resulting in partial loss or total obstruction of oxygen-rich blood flow from the lungs to the heart. These patients typically present with shortness of breath, fatigue, and cyanosis. The current treatment focuses on widening the stenotic portion of the pulmonary vein surgically or by means of intracatheter balloon dilation and/or stent placement (64–66). Lung transplantation, which replaces the lungs and the involved pulmonary veins, is an alternative treatment in patients with severe pulmonary vein stenosis.

CT imaging features.—Pulmonary vein stenosis usually occurs at the pulmonary venous and left atrial junction (39,66) (Fig 12). However, the intraparenchymal segment of the pulmonary vein may also become involved (39). Although echocardiography, nuclear medicine lung scanning, and cardiac catheterization are currently available studies for use in diagnosing and monitoring pulmonary vein stenosis, CT combining a CT angiography protocol with thin-section lung window images is also particularly helpful (65). Common CT findings include pulmonary vein narrowing associated with thickening of the vein wall and pleural thickening, a lack of pulmonary venous reflux from the left atrium, absence of a connection between the juxtaatrial part of the pulmonary veins and left atrium, and systemic-to–pulmonary artery shunt in a retrograde manner (39,63–67). Unilateral reticular opacities with septal lines in the adjacent lung may be also seen.

View larger version (81K): [in this window] [in a new window] [Download PPT slide]   Figure 12: Transverse contrast-enhanced CT image in 3-year-old boy with trisomy 21 and known pulmonary vein stenosis shows a complete left inferior pulmonary vein stenosis (straight arrow) at the pulmonary venous and left atrial junction. Increased soft tissue in the region of the left inferior pulmonary vein observed is likely due to uncontrolled overgrowth of myofibroblast-like connective tissue cells. Also note the small left lung with associated mild left posterior pleural thickening (curved arrow). The right inferior pulmonary vein (RPV) is patent. DA = descending aorta, LA = left atrium.

Pulmonary Varix
Key clinical aspects.—Pulmonary varix is an enlarged pulmonary vein without a large feeding artery or nidus; it is typically observed near its point of entry into the left atrium (18,39,68–72). Pulmonary varices may be congenital or acquired (18,39). Acquired pulmonary varices are associated with chronic pulmonary hypertension and disease of the mitral valve (18,39). Although patients with pulmonary varices are typically asymptomatic, they can manifest symptoms such as hemoptysis at rupture or thromboembolic disease when the varix serves as a thrombogenic nidus (39,72). In asymptomatic patients, once the lesion is correctly diagnosed, treatment is generally not required; however, symptomatic patients may require surgical resection.

CT imaging features.—Depending on its size and location, a pulmonary varix can mimic a solitary pulmonary nodule or mediastinal mass near the left atrium (39,69–72). CT aids in diagnosing pulmonary varix and in differentiating this lesion from other possible differential diagnostic considerations, such as pulmonary nodule or pulmonary AVM. CT images obtained with intravenous contrast material effectively demonstrate contiguity of pulmonary varix with the adjacent pulmonary vein, concurrent contrast material filling within these structures, and absence of a feeding artery (39,69–72) (Fig 13). In cases in which the varix has a tortuous and complex appearance, accurate recognition can be difficult with transverse CT images alone. In such cases, CT with 3D reconstructions demonstrates the vascular anatomy with greater precision.

View larger version (80K): [in this window] [in a new window] [Download PPT slide]   Figure 13: Transverse contrast-enhanced CT image in 14-year-old girl with possible right lower lobe nodule on chest radiographs demonstrates pulmonary varix (PV) involving the right inferior pulmonary vein. CT with contrast medium allows demonstration of contiguity and concurrent contrast enhancement of the pulmonary varix and adjacent left atrium (LA). Normal-sized left inferior pulmonary vein (arrow) is also seen.

	COMBINED ANOMALIES OF PULMONARY ARTERY AND VEINS: PULMONARY AVM

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Key clinical aspects.—Pulmonary AVM, also known as arteriovenous fistula, is a condition in which there is a direct, abnormal communication between the pulmonary artery and pulmonary vein, which is likely due to a developmental defect in the formation of normal pulmonary capillaries (39,73–89). Although the most common cause of pulmonary AVM is congenital, pulmonary AVM can also be acquired. Acquired pulmonary AVM is typically seen in patients with prior congenital cyanotic heart surgeries (ie, Glenn and Fontan procedures), chronic liver disease, or a history of tuberculosis or actinomycosis (39,75–82). Hereditary hemorrhagic telangiectasis (HHT), also known as Rendu-Osler-Weber Syndrome, is an autosomal dominant syndrome frequently associated with pulmonary AVM. Patients with this syndrome often present with a clinical triad of epistaxis, telangiectasis, and a family history (39,74,89). Up to 35% of patients with HHT have pulmonary AVMs (89). Moreover, there is a substantial risk of stroke or cerebral abscess arising from the right-to-left shunt in an unrecognized pulmonary AVM. Hence, family members with HHT should also be screened for pulmonary AVMs (39,89). AVMs smaller than 2 cm are usually asymptomatic. However, larger lesions may result in anatomic right-to-left shunts, which may be complicated by a reduction in arterial oxygen saturation, polycythemia, or paradoxical emboli. Associated symptoms include hemoptysis, dyspnea, chest pain, palpitations, and cyanosis. Unfortunately, patients may remain asymptomatic until they manifest serious complications, including stroke or brain abscess secondary to paradoxical embolization or pulmonary hemorrhage due to AVM rupture (39,87–89). Pulmonary AVMs larger than 2 cm are usually treated with endovascular coil embolization or balloon occlusion (87–89).

CT imaging features.—On chest radiographs, pulmonary AVMs typically appear as sharply marginated pulmonary lesions of uniform density, with associated curvilinear opacities characterized by a feeding artery and a draining vein coursing toward the hilum. However, AVM may also demonstrate more complex appearances such as a plexiform mass of dilated vascular channels or with dilated, tortuous direct communication between an artery and vein (39,84–86,89). Although pulmonary AVM can be seen in all lobes of lungs, it has a lower lobe predilection in 50%–70% of cases (39,89). The detection, characterization, and follow-up of pulmonary AVMs are best accomplished by using CT (Fig 14), specifically multidetector CT, owing to its ability to accurately display complex AVM angioarchitecture. A CT angiography protocol, when combined with 3D reconstruction, is particularly useful in depicting the angioarchitecture of the feeding arteries and draining veins and in estimating the size of the pulmonary AVM (60,85,86) (Fig 15). Approximately 20% of pulmonary AVMs are characterized by complex angioarchitecture with two or more feeding arteries and draining veins (89). Because patients with complex AVMs at presentation have a larger shunt, they are more often symptomatic than patients with simple AVMs. The decision to perform surgical excision or transcatheter embolization planning rests, however, on reaching an accurate estimate of the number, size, and course of vessels (39,87–89). Following embolization of pulmonary AVMs, CT may also aid in confirming the presence or absence of residual AVMs at follow-up (60).

View larger version (155K): [in this window] [in a new window] [Download PPT slide]   Figure 14: Transverse contrast-enhanced CT image shows pulmonary AVM (arrow) in right lower lobe. On transverse CT image, it appears as a lobulated enhancing lesion.

View larger version (113K): [in this window] [in a new window] [Download PPT slide]   Figure 15: Three-dimensional volume-rendered CT image in 40-year-old man with fatigue and severe anemia. CT was performed after abnormal chest radiograph showed a possible right lower lobe pulmonary nodule. CT image shows pulmonary AVM with a feeding artery (straight arrow) and a draining vein (curved arrow). The 3D image is helpful for evaluation of global architecture and size of pulmonary AVM, as well as entire courses of associated vessels. (Three-dimensional imaging reconstruction and image courtesy of Kyongtae T. Bae, MD, PhD.)

	ANOMALIES OF THE AORTOPULMONARY CONNECTION: PATENT DUCTUS ARTERIOSUS

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Key clinical aspects.—Patent ductus arteriosus (PDA) is an abnormal persistence of the normal in utero fetal pulmonary-systemic connection for bypassing the high-resistance lungs and directly supplying blood to the systemic circulation (90–92). Embryologically, ductus originates from primitive sixth aortic arch (90,91). Normally, PDA closes functionally 18–24 hours after birth (90–92). The anatomic closure occurs at 1 month of age (90–92). However, in some cases, the ductus may fail to involute and will remain patent in otherwise healthy neonates or in infants with severe, complex congenital heart disease or lung disease (eg, surfactant deficiency disease and meconium aspiration). Although patients with PDA are initially acyanotic with a left-to-right shunt between the aorta and pulmonary artery, a reversal of the shunt (from right to left) can occur when irreversible pulmonary hypertension develops from the right ventricular pressure overload (92). This condition, also known as Eisenmenger physiology, typically results in cyanosis. The common symptoms in patients with PDA at presentation include murmur, hypoxia, wide pulse pressure, and bounding peripheral pulses (90–92). Less commonly, subacute bacterial endocarditis can also occur secondary to clinically "silent" PDA (90–92). Whereas prostaglandin E1 is used to keep the ductus open in some patients with cyanotic heart disease, indomethacin is used to close the ductus in premature infants unless there is a contraindication, such as an intracranial hemorrhage (90–92). For permanent closure of PDA, surgical clipping or ligation and endovascular closure with occluder devices or coils are currently available treatment options (93–95).

CT imaging features.—Neonates with PDA often demonstrate cardiomegaly at presentation, with increased pulmonary vascularity on radiographs owing to the left-to-right shunts (90–92). The most common CT finding is a tubular structure connecting the descending proximal aorta with the distal main or proximal left pulmonary artery. In neonates with complex congenital heart disease, PDA is frequently an essential part of pulmonary-systemic blood circulation and is relatively large in size (90–92) (Fig 16). In asymptomatic older patients, PDA is usually relatively small, detected incidentally when CT is used to evaluate other disease processes in the chest (Fig 17). For these small PDAs, a CT angiography protocol with oblique sagittal MPR and 3D imaging is particularly helpful, since on transverse CT images alone a small PDA obliquely located in relationship to the x- and y-axes can be missed (96). Three-dimensional imaging is also useful in evaluating a remnant of ductus arteriosus, also known as ductus bump, which is a focal outpouching of the proximal descending aorta (92). The remnant of ductus arteriosus is a normal variant, however, and should not be confused with either PDA or an aneurysm. When a PDA closes, it forms the ligamentum arteriosum, which may calcify. On chest radiographs or CT images, linear calcification representing the calcified ligamentum arteriosum can be seen in the region of the aortopulmonary window (Fig 18).

View larger version (89K): [in this window] [in a new window] [Download PPT slide]   Figure 16a: (a) Transverse contrast-enhanced CT image in 2-day-old girl with respiratory distress and complex congenital heart disease at echocardiography depicts ascending aorta (AA) and hypoplastic descending aorta (arrow). A large vessel adjacent to the ascending aorta is a large PDA. Also noted is right lung agenesis. (b) Sagittal 3D volume-rendered view clearly delineates the complex anatomic relationship among the PDA, ascending aorta (AA), and descending aorta (DA). Ascending aorta is hypoplastic in this case and a large PDA can be mistaken as an ascending aorta on the transverse CT image alone.

View larger version (77K): [in this window] [in a new window] [Download PPT slide]   Figure 16b: (a) Transverse contrast-enhanced CT image in 2-day-old girl with respiratory distress and complex congenital heart disease at echocardiography depicts ascending aorta (AA) and hypoplastic descending aorta (arrow). A large vessel adjacent to the ascending aorta is a large PDA. Also noted is right lung agenesis. (b) Sagittal 3D volume-rendered view clearly delineates the complex anatomic relationship among the PDA, ascending aorta (AA), and descending aorta (DA). Ascending aorta is hypoplastic in this case and a large PDA can be mistaken as an ascending aorta on the transverse CT image alone.

View larger version (90K): [in this window] [in a new window] [Download PPT slide]   Figure 17a: (a) Transverse contrast-enhanced CT image in 52-year-old woman with known PDA and systemic hypertension demonstrates small PDA (arrow) between top of main pulmonary artery (PA) and descending aorta (DA). This CT study was performed for preoperative evaluation for known PDA. (b) Superiosagittal view of 3D volume-rendered image shows entire course of the PDA (arrow), which connects pulmonary artery (PA) and descending aorta (DA). Incidental note is made of an enlarged main pulmonary artery resulting from PDA.

View larger version (115K): [in this window] [in a new window] [Download PPT slide]   Figure 17b: (a) Transverse contrast-enhanced CT image in 52-year-old woman with known PDA and systemic hypertension demonstrates small PDA (arrow) between top of main pulmonary artery (PA) and descending aorta (DA). This CT study was performed for preoperative evaluation for known PDA. (b) Superiosagittal view of 3D volume-rendered image shows entire course of the PDA (arrow), which connects pulmonary artery (PA) and descending aorta (DA). Incidental note is made of an enlarged main pulmonary artery resulting from PDA.

View larger version (62K): [in this window] [in a new window] [Download PPT slide]   Figure 18: Transverse unenhanced CT image in 10-year-old girl with cystic fibrosis shows a linear calcification in the aortopulmonary window region consistent with a calcified ligamentum arteriosum (arrow). CT was performed without intravenous contrast medium for evaluation of lung parenchymal changes from cystic fibrosis.

	COMBINED ABNORMAL PARENCHYMA AND ABNORMAL VASCULATURE

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
Hypogenetic Lung Syndrome (Scimitar Syndrome)
Key clinical aspects.—Hypogenetic lung syndrome, also known as congenital pulmonary venolobar syndrome or scimitar syndrome, is a form of a partial anomalous pulmonary venous connection to the inferior vena cava with associated other anomalies including hypoplastic right lung and pulmonary artery, cardiac dextroversion, and anomalous systemic arterial supply to the right lung (21,26,39,97–101). Anomalous venous drainage into portal or hepatic veins has also been reported. Embryologically, it is believed to represent a primary developmental anomaly of the right lung with an associated secondary anomalous pulmonary venous connection. Other associated anomalies are seen in up to 25% of patients with hypogenetic lung syndrome, including atrial and ventricular septal defects, PDA, tetralogy of Fallot, diaphragmatic abnormalities, sequestration, and horseshoe lung (21,26,39,97–101). Patients with hypogenetic lung syndrome have variable symptoms depending on age at presentation and the degree of left-to-right shunting. Infants typically manifest congestive heart failure secondary to right heart volume overload due to drainage of oxygenated blood directly into the inferior vena cava or right atrium instead of the left atrium (98). While young children can be symptomatic due to recurrent right basilar pulmonary infections, hypogenetic lung syndrome can be incidentally detected on chest radiographs in asymptomatic older pediatric patients and adults. In symptomatic patients, particularly when the left-to-right shunt ratio is greater than 2:1, reconnection of the anomalous pulmonary vein into the left atrium and embolization of systemic arterial supply is the treatment of choice (101).

CT imaging features.—The characteristic imaging appearance of hypogenetic lung syndrome includes right lung hypoplasia with associated dextroversion of the heart. A curvilinear, anomalous venous trunk similar in appearance to a scimitar sword is seen in the region of the right inferior heart border, increasing in size as it courses caudally to drain into the inferior vena cava (Fig 19a). CT angiography with 3D reconstruction is particularly helpful in evaluating the entire course of the anomalous scimitar vein and its eventual drainage site, which is most commonly the inferior vena cava. Other less common drainage sites include the superior vena cava, right atrium, azygous vein, portal vein, and hepatic vein (26,39,60,97,100) (Fig 19b). Preoperative evaluation of an anomalous systemic arterial supply, which may be responsible for the clinical symptoms of hemoptysis or pulmonary hypertension, can also be assessed accurately with 3D imaging prior to coil embolization. In addition, CT lung window images and 3D reconstruction of the central airways can show the abnormal lung parenchyma changes (eg, consolidation or bronchiectasis), abnormal lung lobation, and anomalous bronchial branching pattern (100). CT is also helpful in evaluating postoperative complications from reimplantation of the anomalous vein directly into the left atrium, including thrombosis or stenosis of the reimplanted anomalous vein.

View larger version (66K): [in this window] [in a new window] [Download PPT slide]   Figure 19a: (a) Transverse contrast-enhanced CT image in 10-year-old girl with abnormal chest radiographs obtained for evaluation of possible pneumonia. CT image shows an anomalous pulmonary vein (arrow) draining into the inferior vena cava (IVC). Smaller right lung in comparison to the left lung is also seen. (b) Sagittal view of 3D volume-rendered image shows the entire course of an anomalous pulmonary vein (scimitar vein, arrows) draining into the inferior vena cava (IVC).

View larger version (95K): [in this window] [in a new window] [Download PPT slide]   Figure 19b: (a) Transverse contrast-enhanced CT image in 10-year-old girl with abnormal chest radiographs obtained for evaluation of possible pneumonia. CT image shows an anomalous pulmonary vein (arrow) draining into the inferior vena cava (IVC). Smaller right lung in comparison to the left lung is also seen. (b) Sagittal view of 3D volume-rendered image shows the entire course of an anomalous pulmonary vein (scimitar vein, arrows) draining into the inferior vena cava (IVC).

Sequestration
Key clinical aspects.—Pulmonary sequestration is a congenital malformation characterized by dysplastic and nonfunctioning pulmonary tissue without a normal connection with the tracheobronchial tree; its blood supply comes from systemic vessels (19,21,26,37,39,102–108). There are two types of pulmonary sequestration: extralobar sequestration (25%) and intralobar sequestration (75%) (39,102–108) (Table 2). While extralobar sequestration is invested in its own pleura, intralobar sequestration manifests within the lung, but without its own pleura. While there is general agreement that extralobar sequestration is congenital, there is a growing body of data to support the concept that intralobar sequestration stems from recurrent infections that produce aberrant arterial vessels arising from the aorta (26). Both intralobar and extralobar sequestrations are fed by an anomalous arterial supply that generally comes from the descending aorta. The pathway by which venous drainage takes place, however, varies depending on the type of pulmonary sequestration (19,37,107). In an intralobar sequestration, the anomalous venous drainage typically flows via the inferior pulmonary vein. In an extralobar sequestration, however, the anomalous venous drainage is systemic, typically flowing through the azygous vein and less commonly into the portal vein, left subclavian vein, or the internal mammary vein (19,37,107). While intralobar sequestration is rarely associated with other congenital anomalies, extralobar sequestration is associated with up to 60% of other congenital anomalies, including congenital heart disease and diaphragmatic abnormality (39,102,103).

CT imaging features.—Imaging plays an integral part in the diagnosis and preoperative planning of sequestration. The most common radiographic finding in patients with sequestration is a focal lung mass, located within the bilateral lower lobes (98%), with the left side more frequently involved than the right side (26,39,102,103). In symptomatic patients with intralobar sequestration, inflammatory changes due to recurrent infections are usually seen. Intralobar sequestrations that have been complicated by chronic inflammation and recurrent infection often evolve into predominately cystic lesions (108). CT angiography with 3D reconstruction is particularly helpful not only for detecting anomalous arterial vessels, which aids in reaching an accurate diagnosis, but also in evaluating anomalous veins for differentiating between intralobar (Fig 20) and extralobar sequestration (Fig 21). The literature suggests that an understanding of venous drainage anatomy may also be useful in executing a successful surgical resection (16,37,107). Most intralobar sequestrations require lobectomy or at least a segmentectomy of the involved lung. In contrast, an extralobar sequestration with its own lung pleura can be excised without resection of the normal lung tissue (16,37,107). Furthermore, correct preoperative diagnosis of the number and course of anomalous vessels is particularly important because a fatal hemorrhage can occur if one of the anomalous vessels becomes accidentally ligated during surgery (109). Accurate preoperative data in evaluation of pulmonary sequestration is therefore essential to successful surgical outcomes.

View larger version (128K): [in this window] [in a new window] [Download PPT slide]   Figure 20a: (a) Transverse contrast-enhanced maximum intensity projection CT image in 18-month-old boy with right lung mass seen on prior chest radiographs shows an anomalous artery (long arrow) arising from descending aorta (DA) into sequestered lung (S). Two anomalous veins (short arrows) draining into the left atrium are also noted preoperatively. Surgical pathologic specimen was consistent with intralobar sequestration. (b) Sagittal view of 3D volume-rendered image depicts entire course of the anomalous artery (arrow) arising from descending aorta (DA). S = pulmonary sequestration. Unlike a, 3D volume-rendered image also shows depth information.

View larger version (136K): [in this window] [in a new window] [Download PPT slide]   Figure 20b: (a) Transverse contrast-enhanced maximum intensity projection CT image in 18-month-old boy with right lung mass seen on prior chest radiographs shows an anomalous artery (long arrow) arising from descending aorta (DA) into sequestered lung (S). Two anomalous veins (short arrows) draining into the left atrium are also noted preoperatively. Surgical pathologic specimen was consistent with intralobar sequestration. (b) Sagittal view of 3D volume-rendered image depicts entire course of the anomalous artery (arrow) arising from descending aorta (DA). S = pulmonary sequestration. Unlike a, 3D volume-rendered image also shows depth information.

View larger version (103K): [in this window] [in a new window] [Download PPT slide]   Figure 21a: (a) Transverse contrast-enhanced CT image in 8-week-old girl with prenatal diagnosis of left chest mass shows large heterogeneously enhancing extralobar sequestration (S) in the left lower hemithorax. (b) Sagittal view of 3D volume-rendered image clearly demonstrates a complex angioarchitecture of the extralobar sequestration (S). Anomalous artery (short arrow) is arising from celiac artery. Anomalous vein (long arrow) is draining into the portal vein (curved arrow). Recognition of the venous drainage into systemic vessel was helpful to make a correct diagnosis of extralobar sequestration.

View larger version (80K): [in this window] [in a new window] [Download PPT slide]   Figure 21b: (a) Transverse contrast-enhanced CT image in 8-week-old girl with prenatal diagnosis of left chest mass shows large heterogeneously enhancing extralobar sequestration (S) in the left lower hemithorax. (b) Sagittal view of 3D volume-rendered image clearly demonstrates a complex angioarchitecture of the extralobar sequestration (S). Anomalous artery (short arrow) is arising from celiac artery. Anomalous vein (long arrow) is draining into the portal vein (curved arrow). Recognition of the venous drainage into systemic vessel was helpful to make a correct diagnosis of extralobar sequestration.

	SUMMARY

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 
With rapid advances in CT technology in recent years, CT, and in particular multidetector CT, has assumed a pivotal role in the noninvasive evaluation of congenital lung anomalies. Advanced CT postprocessing techniques, including MPR and 3D reconstructions, are essential for accurately diagnosing congenital lung lesions, determining their relationship to adjacent vital structures, identifying other associated anomalies, and planning surgical interventions.

	ESSENTIALS

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 

• Congenital lung anomalies occur with widely varied clinical presentations and imaging appearances.
  
• Although chest radiographs may be used as an initial imaging modality for evaluation of suspected or for incidentally detected congenital lung anomalies, cross-sectional imaging such as CT is usually required for further characterization.
  
• Congenital lung anomalies can be divided into nonvascular (parenchymal) lesions, vascular lesions, and a combination of both.
  
• Proper CT technique is essential for evaluation of congenital lung lesions; CT angiography is particularly useful for evaluation of the vascular component of congenital lung anomalies.
  
• Multiplanar reformation and three-dimensional reconstructions can be helpful for increasing diagnostic accuracy, aiding preoperative evaluation of complex surgical lesions, and improving communication with clinicians as well as patients.
  

	FOOTNOTES

 

Abbreviations: AVM = arteriovenous malformation • CCAM = congenital cystic adenomatoid malformation • CLE = congenital lobar emphysema • HHT = hereditary hemorrhagic telangiectasis • MPR = multiplanar reformation • PDA = patent ductus arteriosus • 3D = three-dimensional

Authors stated no financial relationship to disclose.

	References

TOP ABSTRACT INTRODUCTION TECHNIQUE THE SPECTRUM OF CONGENITAL... NONVASCULAR LESIONS ANOMALIES OF PULMONARY ARTERY ANOMALIES OF PULMONARY VEINS COMBINED ANOMALIES OF PULMONARY... ANOMALIES OF THE AORTOPULMONARY... COMBINED ABNORMAL PARENCHYMA AND... SUMMARY ESSENTIALS References

 

1. Frush DP, Bisset GS 3rd, Hall SC. Pediatric sedation in radiology: the practice of safe sleep. AJR Am J Roentgenol 1996;167:1381–1387.[Abstract/Free Full Text]
2. American Academy of Pediatrics Committee on Drugs: guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures. Pediatrics 1992;89(6 pt 1):1110–1115.[Abstract/Free Full Text]
3. Practice guidelines for sedation and analgesia by non-anesthesiologists: a report by the American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Anesthesiology 1996;84:459–471.[CrossRef][Medline]
4. Lee EY, Siegel MJ. MDCT of tracheobronchial narrowing in pediatric patients. J Thorac Imaging 2007;22:300–309.[CrossRef][Medline]
5. Lee EY, Siegel MJ. Pediatric airways disorders: large airways. In: Boiselle PM, Lynch DA, eds. CT of the airways. Totowa, NJ: Humana, 2008; 351–380.
6. Donnelly LF, Emery KH, Brody AS, et al. Minimizing radiation dose for pediatric body applications for single-detector helical CT: strategies at a large children's hospital. AJR Am J Roentgenol 2001;176:303–306.[Free Full Text]
7. Haaga JR. Radiation dose management weighing risk versus benefit. AJR Am J Roentgenol 2001;177:289–291.[Free Full Text]
8. Paterson A, Frush DP, Donnelly L. Helical CT of the body: are settings adjusted for pediatric patients? AJR Am J Roentgenol 2001;176:297–301.[Abstract/Free Full Text]
9. Slovis TL. The ALARA concept in pediatric CT: myth or reality? Radiology 2002;223:5–6.
10. Siegel MJ, Schmidt B, Bradley D, Suess C, Hildebolt C. Radiation dose and image quality in pediatric CT: effect of technical factors and phantom size and shape. Radiology 2004;233:515–522.[Abstract/Free Full Text]
11. Calhoun PS, Kuszyk B, Heath DG, Carley JC, Fishman EK. Three-dimensional volume rendering of spiral CT data: theory and method. RadioGraphics 1999;19:745–764.[Abstract/Free Full Text]
12. Cody DD. AAPM/RSNA physics tutorial for residents: topics in CT—image processing in CT. RadioGraphics 2002;22:1255–1268.[Abstract/Free Full Text]
13. Lipson SA. Image reconstruction and review. In: Lipson SA. MDCT and 3D workstations. New York, NY: Springer Science and Business Media, 2006; 30–40.
14. Honda O, Johkoh T, Yamamoto S, et al. Comparison of quality of multiplanar reconstructions and direct coronal multidetector CT scans of the lung. AJR Am J Roentgenol 2002;179:875–879.[Abstract/Free Full Text]
15. Siegel MJ. Multiplanar and three-dimensional multi-detector row CT of thoracic vessels and airways in the pediatric population. Radiology 2003;229:641–650.[Abstract/Free Full Text]
16. Lee EY, Siegel MJ, Sierra LM, Foglia RP. Evaluation of angioarchitecture of pulmonary sequestration in pediatric patients using 3D MDCT angiography. AJR Am J Roentgenol 2004;183:183–188.[Abstract/Free Full Text]
17. Panicek DM, Heitzman ER, Randall PA, et al. The continuum of pulmonary developmental anomalies. RadioGraphics 1987;7(4):747–772.[Abstract]
18. Fraser R, Colman N, Muller NL, Pare PD. Developmental and metabolic lung disease. In: Fraser R, Colman N, Muller NL, Pare PD. Synopsis of diseases of the chest. 3rd ed. Philadelphia, Pa: Elsevier Saunders, 2005; 188–221.
19. Webb W, Higgins CB. Congenital bronchopulmonary lesions. In: Webb WR, ed. Thoracic imaging: pulmonary and cardiovascular radiology. Philadelphia, Pa: Lippincott Williams & Wilkins, 2005; 1–29.
20. Chapman KR, Rebuck AS. Spontaneous disappearance of a chronic mediastinal mass. Chest 1985;87:235–236.[CrossRef][Medline]
21. Zylak CJ, Eyler WR, Spizarny DL, Stone CH. Developmental lung anomalies in the adult: radiologic-pathologic correlation. RadioGraphics 2002;22(Spec Issue):S25–S43.[Abstract/Free Full Text]
22. Aktogu S, Yuncu G, Halilcolar H, Ermete S, Buduneli T. Bronchogenic cysts: clinicopathological presentation and treatment. Eur Respir J 1996;9:2017–2021.[Abstract]
23. McAdams HP, Kirejczyk WM, Rosado-de-Christenson ML, Matsumoto S. Bronchogenic cyst: imaging features with clinical and histopathologic correlation. Radiology 2000;217:441–446.[Abstract/Free Full Text]
24. Williams HJ, Johnson KJ. Imaging of congenital cystic lung lesions. Paediatr Respir Rev 2002;3:120–127.[CrossRef][Medline]
25. Zambudio AR, Lanzas JT, Calvo MJ, Fernandez PJ, Paricio PP. Non-neoplastic mediastinal cysts. Eur J Cardiothorac Surg 2002;22:712–716.[Abstract/Free Full Text]
26. Berrocal T, Madrid C, Novo S, Gutierrez J, Arjonilla A, Gomez-Leon N. Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology. RadioGraphics 2003;24:e17. doi: 10.1148/rg.e17. Published November 10, 2003.[Abstract/Free Full Text]
27. Karnak I, Senock ME, Ciftci AO, Buyukpamukcu N. Congenital lobar emphysema: diagnostic and therapeutic considerations. J Pediatr Surg 1999;34:1347–1351.[CrossRef][Medline]
28. Olutoye OO, Coleman BG, Hubbard AM, Adzick NS. Prenatal diagnosis and management of congenital lobar emphysema. J Pediatr Surg 2000;35:792–795.[CrossRef][Medline]
29. Mei-Zahav M, Konen O, Manson D, Langer JC. Is congenital lobar emphysema a surgical disease? J Pediatr Surg 2006;41:1058–1061.[CrossRef][Medline]
30. Ozcelik U, Gocmen A, Kiper N, Dogru D, Dilber E, Yalcin EG. Congenital lobar emphysema: evaluation and long-term follow up of thirty cases at a single center. Pediatr Pulmonol 2003;35:384–391.[CrossRef][Medline]
31. Cleveland RH, Weber B. Retained fetal lung liquid in congenital lobar emphysema: a possible predictor of polyalveolar lobe. Pediatr Radiol 1993;23:291–205.[CrossRef][Medline]
32. Wilson RD, Hedrick HL, Liechty KW, et al. Cystic adenomatoid malformation of the lung: review of genetics, prenatal diagnosis, and in utero treatment. Am J Med Genet A 2006;140:151–155.[Medline]
33. Sauvat F, Michel JL, Benachi A, Edmond S, Revillon Y. Management of asymptomatic neonatal cystic adenomatoid malformations. J Pediatr Surg 2003;38:548–552.[CrossRef][Medline]
34. Usui N, Kamata S, Sawai T, et al. Outcome predictors for infants with cystic lung disease. J Pediatr Surg 2004;39:603–606.[CrossRef][Medline]
35. Khosa JK, Leong SL, Borzi PA. Congenital cystic adenomatoid malformation of the lung: indications and timing of surgery. Pediatr Surg Int 2004;20:505–508.[Medline]
36. Stocker JT, Madewell JE, Drake RM. Congenital cystic adenomatoid malformation of the lung: classification and morphologic spectrum. Hum Pathol 1977;8:155–171.[Medline]
37. Yikilmaz A, Lee EY. CT imaging of mass-like nonvascular pulmonary lesions in children. Pediatr Radiol 2007;37(12):1253–1263.[CrossRef][Medline]
38. Miniati DN, Chintagumpala M, Langston C, et al. Prenatal presentation and outcome of children with pleuropulmonary blastoma. J Pediatr Surg 2006;41:66–71.[CrossRef][Medline]
39. Remy-Jardin M, Remy J, Mayo JR, Muller NL. Vascular anomalies of the lung. In: Remy-Jardin M, Remy J, Mayo JR, Muller NL, eds. CT angiography of the chest. Philadelphia, Pa: Lippincott Williams & Wilkins, 2001; 97–114.
40. Mahnken AH, Wildberger JE, Spuntrup E, Hubner D. Unilateral absence of the left pulmonary artery associated with coronary-to-bronchial artery anastomosis. J Thorac Imaging 2000;15:187–190.[CrossRef][Medline]
41. Catala FJ, Marti-Bonmati L, Morales-Marin P. Proximal absence of the right pulmonary artery in adult: computed tomography and magnetic resonance findings. J Thorac Imaging 1993;8:244–247.[Medline]
42. Rene M, Sans J, Dominguez J, Sancho C, Valldeperas J. Unilateral pulmonary artery agenesis presenting with hemoptysis: treatment by embolization of systemic collaterals. Cardiovasc Intervent Radiol 1995;18:251–254.[Medline]
43. Berdon WE. Rings, slings, and other things: vascular compression of the infant trachea updated from the midcentury to the millennium—the legacy of Robert E. Gross, MD, and Edward B.D. Neuhauser, MD. Radiology 2000;216:624–632.[Abstract/Free Full Text]
44. Woods RK, Sharp RJ, Holcomb GW 3rd, et al. Vascular anomalies and tracheoesophageal compression: a single institution's 25-year experience. Ann Thorac Surg 2001;72:434–438.[Abstract/Free Full Text]
45. Lee KH, Yoon CS, Choe KO, et al. Use of imaging for assessing anatomical relationships of tracheobronchial anomalies associated with left pulmonary artery sling. Pediatr Radiol 2001;31:269–278.[CrossRef][Medline]
46. Hodina M, Wicky S, Payot M, Sekarski N, Gudinchet F. Non-invasive imaging of the ring-sling complex in children. Pediatr Cardiol 2001;22:333–337.[Medline]
47. Backer CL. Vascular rings and pulmonary artery sling. In: Mavroudis C, Backer CL, eds. Pediatric cardiac surgery. 3rd ed. Philadelphia, Pa: Mosby, 2003; 234–250.
48. Backer CL, Marvoudis C, Rigsby CK, Holinger LD. Trends in vascular ring surgery. J Thorac Cardiovasc Surg 2005;129:1339–1347.[Abstract/Free Full Text]
49. Newman B, Meza MP, Towbin RB, Nido PD. Left pulmonary artery sling diagnosis and delineation of associated tracheobronchial anomalies with MR. Pediatr Radiol 1996;26:661–668.[CrossRef][Medline]
50. Fiore AC, Brown JW, Weber TR, Turrentine MW. Surgical treatment of pulmonary artery sling and tracheal stenosis. Ann Thorac Surg 2005;79:38–46.[Abstract/Free Full Text]
51. Lee EY. MDCT and 3D evaluation of type 2 hypoplastic pulmonary artery sling associated with right lung agenesis, hypoplastic aortic arch, and long segment tracheal stenosis. J Thorac Imaging 2007;22(4):346–350.[Medline]
52. Agent AC, Cremin BJ. Computer tomography in agenesis of the lung in infants. Br J Radiol 1992;65:221–234.[CrossRef][Medline]
53. Mardini MK, Nyhan WL. Agenesis of the lung: report of four cases with unusual anomalies. Chest 1985;87:522–527.[CrossRef][Medline]
54. Knowles S, Thomas RM, Lindenbaum RH, Keeling JW, Winter RM. Pulmonary agenesis as a part of the VACTERL sequence. Arch Dis Child 1988;63:723–726.[Abstract/Free Full Text]
55. Nazaroglu H, Mete A, Bukte Y, Simsek M. Agenesis of the right lung presenting as a pulmonary infection. Clin Radiol 2002;57:529–530.[Medline]
56. Newman B, Gondor M. MR evaluation of right pulmonary agenesis and vascular airway compression in pediatric patients. AJR Am J Roentgenol 1997;168:55–58.[Abstract/Free Full Text]
57. Ootaki Y, Yamaguchi N, Yoshimura N, Oka S. Pulmonary agenesis with congenital heart disease. Pediatr Cardiol 2004;25:145–148.[CrossRef][Medline]
58. Steadland KM, Langham MR Jr, Greene MA, Bagwell CE, Kays DW, Talbert JL. Unilateral pulmonary agenesis, esophageal atresia, and distal tracheoesophageal fistula. Ann Thorac Surg 1995;59:511–513.[Abstract/Free Full Text]
59. Nazir Z, Qazi SH, Ahmed N, Atiq M, Billoo AG. Pulmonary agenesis: vascular airway compression and gastroesophageal reflux influence outcome. J Pediatr Surg 2006;41:1165–1169.[CrossRef][Medline]
60. Daltro P, Fricke BL, Kuroki I, Domingues R, Donnelly LF. CT of congenital lung lesions in pediatric patients. AJR Am J Roentgenol 2004;183:1497–1506.[Free Full Text]
61. Maltz DL, Nadas AS. Agenesis of the lung: presentation of eight new cases and review of the literature. Pediatrics 1968;42:175–188.[Abstract/Free Full Text]
62. Vettraino IM, Tawil A, Comstock CH. Bilateral pulmonary agenesis: prenatal sonographic appearance simulates diaphragmatic hernia. J Ultrasound Med 2003;22:723–726.[Free Full Text]
63. Mortensson W, Lundstrom NR. Congenital obstruction of the pulmonary veins at their atrial junctions: review of the literature and a case report. Am Heart J 1974;87:359–362.[CrossRef][Medline]
64. Endo M, Yamaki S, Ohmi M, Tabayashi K. Pulmonary vascular changes induced by congenital obstruction of pulmonary venous return. Ann Thorac Surg 2000;69:193–197.[Abstract/Free Full Text]
65. Ohtsuki S, Baba K, Kataoka K, et al. Usefulness of helical computed tomography in diagnosing pulmonary vein stenosis in infants. Acta Med Okayama 2005;59:93–98.[Medline]
66. Devaney EJ, Chang AC, Ohye RG, Bove EL. Management of congenital and acquired pulmonary vein stenosis. nAnn Thorac Surg 2006;81:992–995.
67. Chakrabarti S, Tsao S, Vettukattil JJ, Gnanapragasam JP. Pulmonary vein stenosis mimicking chronic lung disease. Acta Paediatr 2003;92:857–858.[CrossRef][Medline]
68. Asayama J, Shiguma R, Katsume H, Ijichi H. Pulmonary varix. Angiology 1984;35:735–739.[Abstract/Free Full Text]
69. Borkowski GP, O'Donovan PB, Troup BR. Pulmonary varix: CT findings. J Comput Assist Tomogr 1981;5:827–829.[Medline]
70. Chaise LS, Soulen R, Teplick S, Patrick H. Computed tomographic diagnosis of pulmonary varix. J Comput Tomogr 1983;7:281–284.[CrossRef][Medline]
71. Vanherreweghe E, Rigauts H, Bogaerts Y, Meeus L. Pulmonary vein varix: diagnosis with multislice helical CT. Eur Radiol 2000;10:1315–1317.[CrossRef][Medline]
72. Ferretti GR, Arbib F, Bertrand B, Coulomb M. Haemoptysis associated with pulmonary varices: demonstration using computed tomography angiography. Eur Respir J 1998;12:989–992.[Abstract]
73. Gossage JR, Kanj G. Pulmonary arteriovenous malformation: a state of the art review. Am J Respir Crit Care Med 1998;158:643–661.[Free Full Text]
74. Shovlin CL, Letarte M. Hereditary haemorrhagic telangiectasia and pulmonary arteriovenous malformations: issues in clinical management and review of pathogenic mechanisms. Thorax 1999;54:714–729.[Free Full Text]
75. Srivastava D, Preminger T, Lock JE, et al. Hepatic venous blood and the development of pulmonary arteriovenous malformations in congenital heart disease. Circulation 1995;92:1217–1222.[Abstract/Free Full Text]
76. Shah MJ, Rychik J, Fogel MA, Murphy JD, Jacobs ML. Pulmonary AV malformations after superior cavopulmonary connection: resolution after inclusion of hepatic veins in the pulmonary circulation. Ann Thorac Surg 1997;63:960–963.[Abstract/Free Full Text]
77. Schraufnagel DE, Kay JM. Structural and pathologic changes in the lung vasculature in chronic liver disease. Clin Chest Med 1996;17:1–15.[CrossRef][Medline]
78. Lee KN, Lee HJ, Shin WW, Webb WR. Hypoxemia and liver cirrhosis (hepatopulmonary syndrome) in eight patients: comparison of the central and peripheral pulmonary vasculature. Radiology 1999;211:549–553.[Abstract/Free Full Text]
79. Oh YW, Kang EY, Lee NJ, Suh WH, Godwin JD. Thoracic manifestations associated with advanced liver disease. J Comput Assist Tomogr 2000;24:699–705.[CrossRef][Medline]
80. McAdams HP, Erasmus J, Crockett R, Mitchell J, Godwin JD, McDermott VG. The hepatopulmonary syndrome: radiologic findings in 10 patients. AJR Am J Roentgenol 1996;166:1379–1385.[Abstract/Free Full Text]
81. Lundell C, Finck E. Arteriovenous fistulas originating from Rasmussen aneurysms. AJR Am J Roentgenol 1983;140:687–688.[Free Full Text]
82. Braun RA, Buchmiller TL, Khankhanian N. Pulmonary arteriovenous malformations complicating coccidioidal pneumonia. Ann Thorac Surg 1995;60:454–457.[Abstract/Free Full Text]
83. Stagaman DJ, Presti C, Rees C, Miller DD. Septic pulmonary arteriovenous fistula: an unusual conduit for systemic embolization in right-sided valvular endocarditis. Chest 1990;97:1484–1486.[CrossRef][Medline]
84. Remy J, Remy-Jardin M, Giraud F, Wattinne L. Angioarchitecture of pulmonary arteriovenous malformations: clinical utility of three-dimensional helical CT. Radiology 1994;191:657–664.[Abstract/Free Full Text]
85. Remy-Jardin M, Remy J. Spiral CT angiography of the pulmonary circulation. Radiology 1999;212:615–636.[Abstract/Free Full Text]
86. Hofmann LV, Kuszyk BS, Mitchell SE, Horton KM, Fishman EK. Angioarchitecture of pulmonary arteriovenous malformations: characterization using volume-rendered 3-D CT angiography. Cardiovasc Intervent Radiol 2000;23:165–170.[CrossRef][Medline]
87. White RI Jr, Lynch-Nyhan A, Terry P, et al. Pulmonary arteriovenous malformations: techniques and long-term outcome of embolotherapy. Radiology 1988;169:663–669.
88. Lee DW, White RI Jr, Egglin TK, et al. Embolotheraphy of large pulmonary arteriovenous malformations: long-term results. Ann Thorac Surg 1997;64:930–940.[Abstract/Free Full Text]
89. Donnelly LF. Chest. In: Donnelly LF, ed. Diagnostic imaging pediatrics. Salt Lake City, Utah: Amirsys, 2005; 118–120.
90. Gersony W. Patent ductus arteriosus and other aortopulmonary anomalies. In: Moller JH, Hoffman JIE, eds. Pediatric cardiovascular medicine. Philadelphia, Pa: Churchill Livingstone, 2000; 232–334.
91. Hillman ND, Mavroudis C, Backer CL. Patent ductus arteriosus. In: Mavroudis C, Backer CL, eds. Pediatric cardiac surgery. 3rd ed. Philadelphia, Pa: Mosby, 2003; 223–233.
92. Donnelly LF. Cardiac. In: Donnelly LF, ed. Diagnostic imaging pediatrics. Salt Lake City, Utah: Amirsys, 2005; 18–20.
93. Wyllie J. Treatment of patent ductus arteriosus. Semin Neonatol 2003;8:425–432.[CrossRef][Medline]
94. Grifka RG. Transcatheter closure of the patent ductus arteriosus. Catheter Cardiovasc Interv 2004;61:554–570.[CrossRef][Medline]
95. Thanopoulos BD, Hakim FA, Hiari A, Tsaousis GS, Paphitis C, Hijazi ZM. Patent ductus arteriosus equipment and technique: amplatzer duct occluder—intermediate-term follow-up and technical considerations. J Interv Cardiol 2001;14:247–254.[CrossRef][Medline]
96. Lee EY, Siegel MJ, Hildebolt CF, Gutierrez FR, Bhalla S, Fallah JH. MDCT evaluation of thoracic aortic anomalies in pediatric patients and young adults: comparison of axial, multiplanar, and 3D images. AJR Am J Roentgenol 2004;182:777–784.
97. Woodring JH, Howard TA, Kanga JF. Congenital pulmonary venolobar syndrome revisited. RadioGraphics 1994;14:349–369.[Abstract]
98. Huddleston CB, Exil V, Canter CE, Mendeloff EN. Scimitar syndrome presenting in infancy. Ann Thorac Surg 1999;67:154–159.[Abstract/Free Full Text]
99. Huddleston CB, Mendeloff EN. Scimitar syndrome. Adv Card Surg 1999;11:161–178.[Medline]
100. Konen E, Raviv-Zilka L, Cohen RA, et al. Congenital pulmonary venolobar syndrome: spectrum of helical CT findings with emphasis on computerized reformatting. RadioGraphics 2003;23:1175–1184.[Abstract/Free Full Text]
101. Donnelly LF. Cardiac. In: Diagnostic imaging pediatrics. Salt Lake City, Utah: Amirsys, 2005; 98–101.
102. Corbett HJ, Humphrey GM. Pulmonary sequestration. Paediatr Respir Rev 2004;5:59–68.[CrossRef][Medline]
103. Freedom RM, Yoo SJ, Goo HW, Mikailian H, Anderson RH. The bronchopulmonary foregut malformation complex. Cardiol Young 2006;16:229–251.[CrossRef][Medline]
104. Frush DP, Donnelly LF. Pulmonary sequestration spectrum: a new spin with helical CT. AJR Am J Roentgenol 1997;169:679–682.[Free Full Text]
105. Bolca N, Topal U, Bayram S. Bronchopulmonary sequestration: radiologic findings. Eur J Radiol 2004;52:185–191.[CrossRef][Medline]
106. Ahmed M, Jacobi V, Vogl TJ. Multislice CT and CT angiography for non-invasive evaluation of bronchopulmonary sequestration. Eur Radiol 2004;14:2141–2143.[CrossRef][Medline]
107. Lee EY, Dillon JE, Callahan MJ, Voss SD. 3D multidetector CT angiographic evaluation of extralobar pulmonary sequestration with anomalous venous drainage into the left internal mammary vein in a paediatric patient. Br J Radiol 2006;79:e99–102. doi:10.1259/bjr/45058144.[Abstract/Free Full Text]
108. Frazier AA, Rosado de Christenson ML, Stocker JT, Templeton PA. Intralobar sequestration: radiologic-pathologic correlation. RadioGraphics 1997;17:725–745.[Abstract]
109. Felker RE, Tonkin IL. Imaging of pulmonary sequestration. AJR Am J Roentgenol 1990;154:241–249.[Free Full Text]

This article has been cited by other articles:

				E. Y. Lee and P. M. Boiselle Tracheobronchomalacia in Infants and Children: Multidetector CT Evaluation Radiology, July 1, 2009; 252(1): 7 - 22. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lee, E. Y. Articles by Cleveland, R. H. Search for Related Content PubMed PubMed Citation Articles by Lee, E. Y. Articles by Cleveland, R. H.