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Congenital Pulmonary Venolobar Syndrome: Spectrum of Helical CT Findings with Emphasis on Computerized Reformatting¹

¹ From the Department of Diagnostic Imaging (E.K., L.R.Z., M.K., G.G., J.R.) and the Pediatric Cardiology Unit (J.H.), Chaim Sheba Medical Center, Tel-Aviv University, Tel Hashomer 52662, Israel; the Department of Diagnostic Imaging, Children’s Hospital, Oakland, Calif (R.A.C.); the Department of Diagnostic Imaging, Rambam Medical Center, Technion-Israel Institute of Technology, Haifa, Israel (M.E., A.O.); the Department of Diagnostic Imaging, Hadassah University Hospital, Jerusalem, Israel (I.B.M., J.B.Z.); and the Department of Diagnostic Imaging, Sapir Medical Center, Tel-Aviv University, Kfar Sava, Israel (O.K.). Recipient of a Cum Laude award for an education exhibit at the 2002 RSNA scientific assembly. Received January 8, 2003; revision requested March 6 and received April 17; accepted April 21. Address correspondence to E.K. (e-mail: konen_e@yahoo.ca).

	Abstract

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
The term congenital pulmonary venolobar syndrome refers to a wide spectrum of pulmonary developmental anomalies that may appear singly or in combination. The main components of congenital pulmonary venolobar syndrome are hypogenetic lung (including lobar agenesis, aplasia, or hypoplasia), partial anomalous pulmonary venous return, absence of pulmonary artery, pulmonary sequestration, systemic arterialization of lung, absence of inferior vena cava, and accessory diaphragm. The recent introduction of multisection helical computed tomography (CT), combined with use of advanced postprocessing graphic workstations, allows improved noninvasive delineation of complex congenital anomalies. A single fast (5–15-second) CT scan now enables the radiologist to (a) generate angiogram-like images of the anomalous pulmonary arteries and veins; (b) demonstrate tracheobronchial abnormalities by generating simulated bronchographic or bronchoscopic images; and (c) depict associated parenchymal abnormalities on axial, coronal, or sagittal images, which once represented an important advantage of magnetic resonance imaging over CT. Multisection helical CT is a helpful diagnostic tool in the preoperative evaluation of patients with suspected congenital pulmonary venolobar syndrome.

© RSNA, 2003

Index Terms: Bronchopulmonary sequestration, 60.145 • Lung, abnormalities, 60.142, 60.145 • Lung, CT, 60.1211 • Venolobar syndrome, 60.14

	LEARNING OBJECTIVES

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
After reading this article and taking the test, the reader will be able to:

• Describe the main components of congenital pulmonary venolobar syndrome.
  
• Recognize the most common vascular, airway, and pulmonary parenchymal CT findings in affected patients.
  
• Select a scanning protocol that will allow optimal anatomic evaluation with minimal radiation exposure.
  

	Introduction

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
The term congenital pulmonary venolobar syndrome was coined by Felson (1) and comprises a heterogeneous group of uncommon abnormalities that may occur singly or in combination and that involve anomalous connections of the pulmonary parenchyma, the pulmonary and systemic vasculature, and, rarely, the gastrointestinal tract (1–3). Although most patients are asymptomatic, some with concurrent cardiac anomalies or severe forms of pulmonary atresia or hypoplasia may have clinical symptoms at an early age. Surgical intervention may be required in selected cases involving intractable infection, hemoptysis, and congestive heart failure or pulmonary hypertension due to excessive shunting (4,5). Identification of abnormal pulmonary and systemic vessels as well as tracheobronchial anomalies is essential for accurate diagnosis in the preoperative evaluation of affected patients.

Traditionally, angiography has been the technique of choice for imaging of vascular anomalies, especially when pulmonary sequestration or hypogenetic lung syndrome (scimitar syndrome) is suspected (5,6). Previous studies performed with earlier generations of computed tomography (CT) scanners have shown CT to be helpful in the evaluation of congenital pulmonary venolobar syndrome but incapable of demonstrating the anomalous vessels in many cases (7–10). More recently, several studies have suggested the use of CT angiography as a noninvasive alternative in cases of pulmonary sequestration or hypogenetic lung syndrome (11–17). The recent introduction of multisection helical CT, combined with use of advanced postprocessing graphic workstations, allows improved delineation of the complex and variable anatomic abnormalities seen in patients with congenital pulmonary venolobar syndrome.

In this article, we discuss the methods and technique used in a study of 31 patients with various manifestations of congenital pulmonary venolobar syndrome (pulmonary sequestrations and variants, partial anomalous pulmonary venous return, horseshoe lung, proximal pulmonary arterial interruption) that was performed with multisection helical CT and computerized reformatting. We also discuss and illustrate the spectrum of common and uncommon imaging findings in these patients. In addition, we discuss the possible drawbacks of CT in the evaluation of patients with congenital pulmonary venolobar syndrome.

	Methods and Technique

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
We retrospectively reviewed CT angiographic studies performed at four medical centers between January 1995 and July 2000 in 31 patients with congenital pulmonary venolobar syndrome. Nineteen patients were male and 12 were female. Patient age ranged from 2 days to 42 years (mean age, 10.9 years). Twenty-three patients were under 18 years old, and 11 were neonates. Clinical manifestations prior to CT angiography included recurrent bouts of pneumonia (n = 9), prenatally diagnosed pulmonary sequestration (n = 8), congestive heart failure (n = 9), incidental radiographic findings in asymptomatic adult patients (n = 5), a low Apgar score at birth (n = 2), and mild-effort dyspnea and wheezing (n = 1). Six of the eight patients in whom pulmonary sequestration was prenatally diagnosed were asymptomatic.

Nonionic iodinated contrast material (iohexol [Omnipaque 300; Nycomed, New York, NY or Schering, Berlin, Germany] or ioversol [Optiray 320; Mallinckrodt Medical, St Louis, Mo]) was used. The contrast material (mean dose, 2 mL/kg) was injected into a peripheral vein of the arm with a power injector at a rate of 1–4 mL/sec.

The examinations were performed with either a double-detector helical CT scanner (Twin; Marconi, Cleveland, Ohio) or a quad-section CT scanner (MX-8000, Marconi) with a pitch of 1.5 or 2. Scanning time varied from 12 to 30 seconds. Collimation was 1 mm in 10 patients, 2 mm in 13 patients, 2.5 mm in seven patients, and 4 mm in one patient, with 30%–50% reconstruction overlap between sections. Scanning was performed during a single breath hold in cooperative patients or during quiet respiration in infants and young children. Computerized reformatting was performed with an image processing workstation running on a Silicon Graphics O2 platform (Omniview MX, Marconi). The following computerized reformatting techniques were used prospectively at the original institutions: multiplanar reformatting (n = 23), shaded surface display (SSD) (n = 7), maximum intensity projection (n = 6), minimum intensity projection (n = 6), volume rendering (n = 4), and virtual bronchoscopy (n = 2). Virtual bronchoscopic images were generated to correspond to fiberoptic bronchoscopic images (ie, appearing as if the patient were in a prone position).

CT revealed 22 sequestrations in 21 patients (one patient had a bilateral sequestration, and three patients had associated partial anomalous pulmonary venous return), hypogenetic lung in seven, absence of the left main pulmonary artery in four, systemic arterialization of lung in one, and horseshoe lung in one. In 21 patients, CT findings could be correlated with findings at other procedures, including angiography (n = 9; indications for angiography included shunt quantification and embolization of aberrant arteries in patients with congestive heart failure), surgery (n = 8), Doppler ultrasonography (US) (n = 2), and bronchoscopy (n = 2). Clinical follow-up is ongoing but thus far uneventful in three additional asymptomatic infants with a prenatal diagnosis of sequestration.

	Pulmonary Sequestrations and Variants

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
Pulmonary sequestration is defined as a segment of lung parenchyma that is separated from the tracheobronchial tree and is supplied with blood from a systemic rather than a pulmonary artery (1,18). The blood supply usually comes from the descending thoracic aorta, but in about 20% of cases it comes from the upper abdominal aorta, celiac artery (Fig 1), or splenic artery (18). Sequestrations may be either intralobar or extralobar. Intralobar sequestrations are contained within the visceral pleura of the normal adjacent lung. They are more common than extralobar sequestrations by a 3:1 ratio, and over 50% of intralobar sequestrations may be asymptomatic by the time the patient reaches 20 years of age. In 95% of cases, venous drainage is to the pulmonary veins, resulting in a unique left-to-left shunt. Intralobar sequestrations are associated with other anomalies (usually diaphragmatic hernia) in about 15% of cases. In contrast, extralobar sequestrations are contained within a distinct visceral pleural coat. Only 10% of extralobar sequestrations remain asymptomatic, and most occur in the first 6 months of life. More than 80% drain into the right side of the heart via the azygos vein, hemiazygos vein, and inferior vena cava (IVC), resulting in a left-to-right shunt. In 65% of cases, there are associated anomalies (Fig 2), the most common being diaphragmatic hernia. Rare variants of sequestration such as bilateral sequestration (Fig 3) and gastric or esophageal lung (Fig 3e) (3) have been reported in both extra- and intralobar sequestrations.

View larger version (115K): [in this window] [in a new window] [Download PPT slide]   Figure 1a.  Pulmonary sequestration in a 6-year-old boy with recurrent episodes of right lower lobe pneumonia. (a) Axial CT angiogram obtained at the level of the lung bases shows a consolidation with large vessels centrally (arrows) in the right lower lobe. (b) Axial CT angiogram obtained inferior to a shows that the vessels originate from a large artery (arrow) that crosses inferior to the diaphragm. (c, d) SSD (c) and magnified volume-rendered (d) reformatted images clearly demonstrate a systemic aberrant artery (arrow) that originates from the celiac trunk (arrowhead in d) and supplies the right lower lung. In c, the trachea and lungs are highlighted in blue and the ribs and lungs are partially transparent. AO = aorta. Surgery revealed an intralobar sequestration.

View larger version (120K): [in this window] [in a new window] [Download PPT slide]   Figure 1b.  Pulmonary sequestration in a 6-year-old boy with recurrent episodes of right lower lobe pneumonia. (a) Axial CT angiogram obtained at the level of the lung bases shows a consolidation with large vessels centrally (arrows) in the right lower lobe. (b) Axial CT angiogram obtained inferior to a shows that the vessels originate from a large artery (arrow) that crosses inferior to the diaphragm. (c, d) SSD (c) and magnified volume-rendered (d) reformatted images clearly demonstrate a systemic aberrant artery (arrow) that originates from the celiac trunk (arrowhead in d) and supplies the right lower lung. In c, the trachea and lungs are highlighted in blue and the ribs and lungs are partially transparent. AO = aorta. Surgery revealed an intralobar sequestration.

View larger version (133K): [in this window] [in a new window] [Download PPT slide]   Figure 1c.  Pulmonary sequestration in a 6-year-old boy with recurrent episodes of right lower lobe pneumonia. (a) Axial CT angiogram obtained at the level of the lung bases shows a consolidation with large vessels centrally (arrows) in the right lower lobe. (b) Axial CT angiogram obtained inferior to a shows that the vessels originate from a large artery (arrow) that crosses inferior to the diaphragm. (c, d) SSD (c) and magnified volume-rendered (d) reformatted images clearly demonstrate a systemic aberrant artery (arrow) that originates from the celiac trunk (arrowhead in d) and supplies the right lower lung. In c, the trachea and lungs are highlighted in blue and the ribs and lungs are partially transparent. AO = aorta. Surgery revealed an intralobar sequestration.

View larger version (125K): [in this window] [in a new window] [Download PPT slide]   Figure 1d.  Pulmonary sequestration in a 6-year-old boy with recurrent episodes of right lower lobe pneumonia. (a) Axial CT angiogram obtained at the level of the lung bases shows a consolidation with large vessels centrally (arrows) in the right lower lobe. (b) Axial CT angiogram obtained inferior to a shows that the vessels originate from a large artery (arrow) that crosses inferior to the diaphragm. (c, d) SSD (c) and magnified volume-rendered (d) reformatted images clearly demonstrate a systemic aberrant artery (arrow) that originates from the celiac trunk (arrowhead in d) and supplies the right lower lung. In c, the trachea and lungs are highlighted in blue and the ribs and lungs are partially transparent. AO = aorta. Surgery revealed an intralobar sequestration.

View larger version (113K): [in this window] [in a new window] [Download PPT slide]   Figure 2a.  Pulmonary sequestration with an associated suspected gastric duplication in an asymptomatic male neonate. (a) Coronal multiplanar reformatted image shows an aberrant artery (arrowhead) that arises from the descending thoracic aorta and supplies a mass in the left lung base. An adjacent infradiaphragmatic cystic mass is also noted (C). (b) On an axial image obtained at the level of the gastric fundus, the cystic mass (C) is seen to project into the stomach, a finding that is compatible with gastric duplication.

View larger version (130K): [in this window] [in a new window] [Download PPT slide]   Figure 2b.  Pulmonary sequestration with an associated suspected gastric duplication in an asymptomatic male neonate. (a) Coronal multiplanar reformatted image shows an aberrant artery (arrowhead) that arises from the descending thoracic aorta and supplies a mass in the left lung base. An adjacent infradiaphragmatic cystic mass is also noted (C). (b) On an axial image obtained at the level of the gastric fundus, the cystic mass (C) is seen to project into the stomach, a finding that is compatible with gastric duplication.

View larger version (154K): [in this window] [in a new window] [Download PPT slide]   Figure 3a.  Bilateral pulmonary sequestration that caused congestive heart failure in a male neonate. The patient’s condition was diagnosed prenatally at US. (a) Combined SSD and multiplanar reformatted image shows an anomalous artery that arises from the descending thoracic aorta and bifurcates to supply two enhancing soft-tissue masses in the lung bases. (b, c) Curvilinear multiplanar reformatted images clearly delineate the anomalous arteries in the right (b) and left (c) lung bases. (d) Findings on an aortogram obtained before successful embolization of the aberrant arteries are virtually identical to and thereby help confirm the CT angiographic findings (cf a). (e) Axial minimum-intensity-projection reformatted image reveals an accessory aerated aberrant bronchial tree (arrow) that connects the two masses. The aberrant bronchial tree is separated from the normal tracheobronchial tree, a finding that suggests a rare connection to the esophagus or stomach. AO = aorta. (f) On a follow-up CT angiogram obtained 1 year after embolization, the volume of the left sequestration is significantly reduced and the right sequestration has almost totally disappeared. Note the steel coils (arrows) used for embolization of the right aberrant artery.

View larger version (136K): [in this window] [in a new window] [Download PPT slide]   Figure 3b.  Bilateral pulmonary sequestration that caused congestive heart failure in a male neonate. The patient’s condition was diagnosed prenatally at US. (a) Combined SSD and multiplanar reformatted image shows an anomalous artery that arises from the descending thoracic aorta and bifurcates to supply two enhancing soft-tissue masses in the lung bases. (b, c) Curvilinear multiplanar reformatted images clearly delineate the anomalous arteries in the right (b) and left (c) lung bases. (d) Findings on an aortogram obtained before successful embolization of the aberrant arteries are virtually identical to and thereby help confirm the CT angiographic findings (cf a). (e) Axial minimum-intensity-projection reformatted image reveals an accessory aerated aberrant bronchial tree (arrow) that connects the two masses. The aberrant bronchial tree is separated from the normal tracheobronchial tree, a finding that suggests a rare connection to the esophagus or stomach. AO = aorta. (f) On a follow-up CT angiogram obtained 1 year after embolization, the volume of the left sequestration is significantly reduced and the right sequestration has almost totally disappeared. Note the steel coils (arrows) used for embolization of the right aberrant artery.

View larger version (135K): [in this window] [in a new window] [Download PPT slide]   Figure 3c.  Bilateral pulmonary sequestration that caused congestive heart failure in a male neonate. The patient’s condition was diagnosed prenatally at US. (a) Combined SSD and multiplanar reformatted image shows an anomalous artery that arises from the descending thoracic aorta and bifurcates to supply two enhancing soft-tissue masses in the lung bases. (b, c) Curvilinear multiplanar reformatted images clearly delineate the anomalous arteries in the right (b) and left (c) lung bases. (d) Findings on an aortogram obtained before successful embolization of the aberrant arteries are virtually identical to and thereby help confirm the CT angiographic findings (cf a). (e) Axial minimum-intensity-projection reformatted image reveals an accessory aerated aberrant bronchial tree (arrow) that connects the two masses. The aberrant bronchial tree is separated from the normal tracheobronchial tree, a finding that suggests a rare connection to the esophagus or stomach. AO = aorta. (f) On a follow-up CT angiogram obtained 1 year after embolization, the volume of the left sequestration is significantly reduced and the right sequestration has almost totally disappeared. Note the steel coils (arrows) used for embolization of the right aberrant artery.

View larger version (129K): [in this window] [in a new window] [Download PPT slide]   Figure 3d.  Bilateral pulmonary sequestration that caused congestive heart failure in a male neonate. The patient’s condition was diagnosed prenatally at US. (a) Combined SSD and multiplanar reformatted image shows an anomalous artery that arises from the descending thoracic aorta and bifurcates to supply two enhancing soft-tissue masses in the lung bases. (b, c) Curvilinear multiplanar reformatted images clearly delineate the anomalous arteries in the right (b) and left (c) lung bases. (d) Findings on an aortogram obtained before successful embolization of the aberrant arteries are virtually identical to and thereby help confirm the CT angiographic findings (cf a). (e) Axial minimum-intensity-projection reformatted image reveals an accessory aerated aberrant bronchial tree (arrow) that connects the two masses. The aberrant bronchial tree is separated from the normal tracheobronchial tree, a finding that suggests a rare connection to the esophagus or stomach. AO = aorta. (f) On a follow-up CT angiogram obtained 1 year after embolization, the volume of the left sequestration is significantly reduced and the right sequestration has almost totally disappeared. Note the steel coils (arrows) used for embolization of the right aberrant artery.

View larger version (131K): [in this window] [in a new window] [Download PPT slide]   Figure 3e.  Bilateral pulmonary sequestration that caused congestive heart failure in a male neonate. The patient’s condition was diagnosed prenatally at US. (a) Combined SSD and multiplanar reformatted image shows an anomalous artery that arises from the descending thoracic aorta and bifurcates to supply two enhancing soft-tissue masses in the lung bases. (b, c) Curvilinear multiplanar reformatted images clearly delineate the anomalous arteries in the right (b) and left (c) lung bases. (d) Findings on an aortogram obtained before successful embolization of the aberrant arteries are virtually identical to and thereby help confirm the CT angiographic findings (cf a). (e) Axial minimum-intensity-projection reformatted image reveals an accessory aerated aberrant bronchial tree (arrow) that connects the two masses. The aberrant bronchial tree is separated from the normal tracheobronchial tree, a finding that suggests a rare connection to the esophagus or stomach. AO = aorta. (f) On a follow-up CT angiogram obtained 1 year after embolization, the volume of the left sequestration is significantly reduced and the right sequestration has almost totally disappeared. Note the steel coils (arrows) used for embolization of the right aberrant artery.

View larger version (123K): [in this window] [in a new window] [Download PPT slide]   Figure 3f.  Bilateral pulmonary sequestration that caused congestive heart failure in a male neonate. The patient’s condition was diagnosed prenatally at US. (a) Combined SSD and multiplanar reformatted image shows an anomalous artery that arises from the descending thoracic aorta and bifurcates to supply two enhancing soft-tissue masses in the lung bases. (b, c) Curvilinear multiplanar reformatted images clearly delineate the anomalous arteries in the right (b) and left (c) lung bases. (d) Findings on an aortogram obtained before successful embolization of the aberrant arteries are virtually identical to and thereby help confirm the CT angiographic findings (cf a). (e) Axial minimum-intensity-projection reformatted image reveals an accessory aerated aberrant bronchial tree (arrow) that connects the two masses. The aberrant bronchial tree is separated from the normal tracheobronchial tree, a finding that suggests a rare connection to the esophagus or stomach. AO = aorta. (f) On a follow-up CT angiogram obtained 1 year after embolization, the volume of the left sequestration is significantly reduced and the right sequestration has almost totally disappeared. Note the steel coils (arrows) used for embolization of the right aberrant artery.

	Partial Anomalous Pulmonary Venous Return

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
Partial anomalous pulmonary venous return is present when one or more, but not all, of the pulmonary veins drain into a systemic vein, resulting in a left-to-right shunt. Partial anomalous pulmonary venous return is usually an isolated finding and is more frequently seen on the right side. Most patients are either mildly symptomatic or asymptomatic.

Hypogenetic lung syndrome (scimitar syndrome) is a rare type of partial anomalous pulmonary venous return in which an anomalous pulmonary vein is the draining vein for part or all of the right lung, emptying into the IVC (Fig 4a–4c) either above or below the diaphragm. The anomalous vein may on occasion drain into the hepatic veins, portal veins, azygous vein, coronary sinus, or right atrium. The anomalous vein is usually associated with various degrees of hypoplasia of the right lung and with a hypoplastic or aplastic pulmonary artery. The right lung may have abnormal lobation (frequently only two lobes), and the bronchographic pattern may mimic that of the left lung (Fig 4d) (8). About one-fourth of affected patients have associated congenital heart disease, most often a sinus venosus atrial septal defect. Reported associated anomalies include bronchogenic cyst, horseshoe lung, accessory diaphragm, and hernia.

View larger version (129K): [in this window] [in a new window] [Download PPT slide]   Figure 4a.  Hypogenetic lung syndrome in a 22-year-old asymptomatic woman. (a) Axial CT angiogram obtained at the level of the lung bases shows a large anomalous vein (*) that drains into a dilated inferior vena cava (IVC). (b) Volume-rendered reformatted image demonstrates that the anomalous vein (*) drains into the IVC below the level of the right hemidiaphragm. L = liver. (c) Anteroposterior venous phase pulmonary angiogram obtained for shunt quantification helps confirm the presence of an anomalous pulmonary vein. (d) On a minimum-intensity-projection reformatted image, the right upper lobe bronchus is not seen, allowing visualization of the associated hypogenetic lung and central bronchi.

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 4b.  Hypogenetic lung syndrome in a 22-year-old asymptomatic woman. (a) Axial CT angiogram obtained at the level of the lung bases shows a large anomalous vein (*) that drains into a dilated inferior vena cava (IVC). (b) Volume-rendered reformatted image demonstrates that the anomalous vein (*) drains into the IVC below the level of the right hemidiaphragm. L = liver. (c) Anteroposterior venous phase pulmonary angiogram obtained for shunt quantification helps confirm the presence of an anomalous pulmonary vein. (d) On a minimum-intensity-projection reformatted image, the right upper lobe bronchus is not seen, allowing visualization of the associated hypogenetic lung and central bronchi.

View larger version (148K): [in this window] [in a new window] [Download PPT slide]   Figure 4c.  Hypogenetic lung syndrome in a 22-year-old asymptomatic woman. (a) Axial CT angiogram obtained at the level of the lung bases shows a large anomalous vein (*) that drains into a dilated inferior vena cava (IVC). (b) Volume-rendered reformatted image demonstrates that the anomalous vein (*) drains into the IVC below the level of the right hemidiaphragm. L = liver. (c) Anteroposterior venous phase pulmonary angiogram obtained for shunt quantification helps confirm the presence of an anomalous pulmonary vein. (d) On a minimum-intensity-projection reformatted image, the right upper lobe bronchus is not seen, allowing visualization of the associated hypogenetic lung and central bronchi.

View larger version (124K): [in this window] [in a new window] [Download PPT slide]   Figure 4d.  Hypogenetic lung syndrome in a 22-year-old asymptomatic woman. (a) Axial CT angiogram obtained at the level of the lung bases shows a large anomalous vein (*) that drains into a dilated inferior vena cava (IVC). (b) Volume-rendered reformatted image demonstrates that the anomalous vein (*) drains into the IVC below the level of the right hemidiaphragm. L = liver. (c) Anteroposterior venous phase pulmonary angiogram obtained for shunt quantification helps confirm the presence of an anomalous pulmonary vein. (d) On a minimum-intensity-projection reformatted image, the right upper lobe bronchus is not seen, allowing visualization of the associated hypogenetic lung and central bronchi.

	Horseshoe Lung

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 5a.  Horseshoe lung in a male neonate. (a) Axial CT scan obtained at the level of the lung bases shows an isthmus of pulmonary parenchyma (arrow) that extends behind the heart and joins the posterobasal segments of both lungs. An anomalous right pulmonary vein (*) drains into the IVC. (b) Volume-rendered reformatted image of the airways and lung parenchyma reveals partial fusion of the lungs posterior to the heart and an abnormal bronchus that arises from the left main bronchus and crosses the thoracic midline. (c) Coronal multiplanar reformatted image shows an anomalous right pulmonary vein (*) that drains into the IVC below the level of the right hemidiaphragm. (d) SSD reformatted image of the pulmonary artery demonstrates an inferior branch (*) that arises from the right pulmonary artery (•) and crosses the midline to the base of the left lung. (e) Anteroposterior arterial phase pulmonary angiogram helps confirm the CT angiographic findings. * = anomalous branch, • = right pulmonary artery.

View larger version (94K): [in this window] [in a new window] [Download PPT slide]   Figure 5b.  Horseshoe lung in a male neonate. (a) Axial CT scan obtained at the level of the lung bases shows an isthmus of pulmonary parenchyma (arrow) that extends behind the heart and joins the posterobasal segments of both lungs. An anomalous right pulmonary vein (*) drains into the IVC. (b) Volume-rendered reformatted image of the airways and lung parenchyma reveals partial fusion of the lungs posterior to the heart and an abnormal bronchus that arises from the left main bronchus and crosses the thoracic midline. (c) Coronal multiplanar reformatted image shows an anomalous right pulmonary vein (*) that drains into the IVC below the level of the right hemidiaphragm. (d) SSD reformatted image of the pulmonary artery demonstrates an inferior branch (*) that arises from the right pulmonary artery (•) and crosses the midline to the base of the left lung. (e) Anteroposterior arterial phase pulmonary angiogram helps confirm the CT angiographic findings. * = anomalous branch, • = right pulmonary artery.

View larger version (99K): [in this window] [in a new window] [Download PPT slide]   Figure 5c.  Horseshoe lung in a male neonate. (a) Axial CT scan obtained at the level of the lung bases shows an isthmus of pulmonary parenchyma (arrow) that extends behind the heart and joins the posterobasal segments of both lungs. An anomalous right pulmonary vein (*) drains into the IVC. (b) Volume-rendered reformatted image of the airways and lung parenchyma reveals partial fusion of the lungs posterior to the heart and an abnormal bronchus that arises from the left main bronchus and crosses the thoracic midline. (c) Coronal multiplanar reformatted image shows an anomalous right pulmonary vein (*) that drains into the IVC below the level of the right hemidiaphragm. (d) SSD reformatted image of the pulmonary artery demonstrates an inferior branch (*) that arises from the right pulmonary artery (•) and crosses the midline to the base of the left lung. (e) Anteroposterior arterial phase pulmonary angiogram helps confirm the CT angiographic findings. * = anomalous branch, • = right pulmonary artery.

View larger version (119K): [in this window] [in a new window] [Download PPT slide]   Figure 5d.  Horseshoe lung in a male neonate. (a) Axial CT scan obtained at the level of the lung bases shows an isthmus of pulmonary parenchyma (arrow) that extends behind the heart and joins the posterobasal segments of both lungs. An anomalous right pulmonary vein (*) drains into the IVC. (b) Volume-rendered reformatted image of the airways and lung parenchyma reveals partial fusion of the lungs posterior to the heart and an abnormal bronchus that arises from the left main bronchus and crosses the thoracic midline. (c) Coronal multiplanar reformatted image shows an anomalous right pulmonary vein (*) that drains into the IVC below the level of the right hemidiaphragm. (d) SSD reformatted image of the pulmonary artery demonstrates an inferior branch (*) that arises from the right pulmonary artery (•) and crosses the midline to the base of the left lung. (e) Anteroposterior arterial phase pulmonary angiogram helps confirm the CT angiographic findings. * = anomalous branch, • = right pulmonary artery.

View larger version (92K): [in this window] [in a new window] [Download PPT slide]   Figure 5e.  Horseshoe lung in a male neonate. (a) Axial CT scan obtained at the level of the lung bases shows an isthmus of pulmonary parenchyma (arrow) that extends behind the heart and joins the posterobasal segments of both lungs. An anomalous right pulmonary vein (*) drains into the IVC. (b) Volume-rendered reformatted image of the airways and lung parenchyma reveals partial fusion of the lungs posterior to the heart and an abnormal bronchus that arises from the left main bronchus and crosses the thoracic midline. (c) Coronal multiplanar reformatted image shows an anomalous right pulmonary vein (*) that drains into the IVC below the level of the right hemidiaphragm. (d) SSD reformatted image of the pulmonary artery demonstrates an inferior branch (*) that arises from the right pulmonary artery (•) and crosses the midline to the base of the left lung. (e) Anteroposterior arterial phase pulmonary angiogram helps confirm the CT angiographic findings. * = anomalous branch, • = right pulmonary artery.

	Pulmonary Arterial Interruption

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

View larger version (140K): [in this window] [in a new window] [Download PPT slide]   Figure 6a.  Interruption of the left pulmonary artery in a 36-year-old man who was born with a persistent truncus arteriosus (surgically repaired in childhood). (a) Axial CT angiogram obtained at the level of the carina shows interruption of the left main pulmonary artery. The left lung is mildly hypoplastic with decreased vascularity. Note the calcified conduit (*) that connects the right ventricle to the main pulmonary artery and an aneurysmal ascending aorta (AO). (b) Coronal multiplanar reformatted image shows peripheral linear areas of increased attenuation in the left lung (arrows). This finding, which was confirmed at angiography, represents collateral vessels that invade the lung through the pleura. Inset demonstrates the plane of reformation.

View larger version (155K): [in this window] [in a new window] [Download PPT slide]   Figure 6b.  Interruption of the left pulmonary artery in a 36-year-old man who was born with a persistent truncus arteriosus (surgically repaired in childhood). (a) Axial CT angiogram obtained at the level of the carina shows interruption of the left main pulmonary artery. The left lung is mildly hypoplastic with decreased vascularity. Note the calcified conduit (*) that connects the right ventricle to the main pulmonary artery and an aneurysmal ascending aorta (AO). (b) Coronal multiplanar reformatted image shows peripheral linear areas of increased attenuation in the left lung (arrows). This finding, which was confirmed at angiography, represents collateral vessels that invade the lung through the pleura. Inset demonstrates the plane of reformation.

View larger version (128K): [in this window] [in a new window] [Download PPT slide]   Figure 7a.  Interruption of the left main pulmonary artery in a 16-year-old boy. (a, b) Axial CT scans obtained at the level of the right main bronchus (a) and bronchus intermedius (b) (arrows) show interruption of the left main pulmonary artery. Note the compressed right main bronchus between the right-sided descending aorta (Ao) and a prominent right main pulmonary artery (RPA). The mediastinum is shifted to the left due to an associated hypoplastic left lung. (c) SSD reformatted image (superior view) delineates the spatial relationship between the prominent single pulmonary artery (blue), the right-sided descending aorta (AO [red]), and the compressed right main bronchus. (d) Virtual bronchoscopic reformatted image obtained at the level of the carina ("supine" position) shows the right main bronchus (R) with a compressed "fishmouth" shape. L = left main bronchus.

View larger version (123K): [in this window] [in a new window] [Download PPT slide]   Figure 7b.  Interruption of the left main pulmonary artery in a 16-year-old boy. (a, b) Axial CT scans obtained at the level of the right main bronchus (a) and bronchus intermedius (b) (arrows) show interruption of the left main pulmonary artery. Note the compressed right main bronchus between the right-sided descending aorta (Ao) and a prominent right main pulmonary artery (RPA). The mediastinum is shifted to the left due to an associated hypoplastic left lung. (c) SSD reformatted image (superior view) delineates the spatial relationship between the prominent single pulmonary artery (blue), the right-sided descending aorta (AO [red]), and the compressed right main bronchus. (d) Virtual bronchoscopic reformatted image obtained at the level of the carina ("supine" position) shows the right main bronchus (R) with a compressed "fishmouth" shape. L = left main bronchus.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 7c.  Interruption of the left main pulmonary artery in a 16-year-old boy. (a, b) Axial CT scans obtained at the level of the right main bronchus (a) and bronchus intermedius (b) (arrows) show interruption of the left main pulmonary artery. Note the compressed right main bronchus between the right-sided descending aorta (Ao) and a prominent right main pulmonary artery (RPA). The mediastinum is shifted to the left due to an associated hypoplastic left lung. (c) SSD reformatted image (superior view) delineates the spatial relationship between the prominent single pulmonary artery (blue), the right-sided descending aorta (AO [red]), and the compressed right main bronchus. (d) Virtual bronchoscopic reformatted image obtained at the level of the carina ("supine" position) shows the right main bronchus (R) with a compressed "fishmouth" shape. L = left main bronchus.

View larger version (119K): [in this window] [in a new window] [Download PPT slide]   Figure 7d.  Interruption of the left main pulmonary artery in a 16-year-old boy. (a, b) Axial CT scans obtained at the level of the right main bronchus (a) and bronchus intermedius (b) (arrows) show interruption of the left main pulmonary artery. Note the compressed right main bronchus between the right-sided descending aorta (Ao) and a prominent right main pulmonary artery (RPA). The mediastinum is shifted to the left due to an associated hypoplastic left lung. (c) SSD reformatted image (superior view) delineates the spatial relationship between the prominent single pulmonary artery (blue), the right-sided descending aorta (AO [red]), and the compressed right main bronchus. (d) Virtual bronchoscopic reformatted image obtained at the level of the carina ("supine" position) shows the right main bronchus (R) with a compressed "fishmouth" shape. L = left main bronchus.

	Drawbacks of CT

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

	Conclusions

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 
Multisection helical CT is a helpful diagnostic tool in the preoperative evaluation of patients with suspected congenital pulmonary venolobar syndrome. It allows detailed evaluation of vascular, tracheobronchial, and pulmonary parenchymal abnormalities with a single short, noninvasive procedure.

	Footnotes

 
Abbreviations: IVC = inferior vena cava, SSD = shaded surface display

	References

Top Abstract LEARNING OBJECTIVES Introduction Methods and Technique Pulmonary Sequestrations and... Partial Anomalous Pulmonary... Horseshoe Lung Pulmonary Arterial Interruption Drawbacks of CT Conclusions References

 

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