Idea Transcript
Back to Basics: Lateral Chest Radiograph
Society of Thoracic Radiology
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Christopher Lee, MD
Disclosures
Annual Meeting and Postgraduate Course • None
Back to Basics: Lateral Chest Radiograph March 11, 2012 Huntington Beach, California
Christopher Lee, M.D. Cardiothoracic Imaging Department of Radiology Keck School of Medicine of USC
Acknowledgements
Introduction
• Robert Suh, M.D. (UCLA Medical Center)
• Education and clinical importance of the lateral chest radiograph have diminished as CT has become more popular – Ease of requesting (and recommending) a chest CT when questionable abnormality seen on frontal CXR
• Radiology trainees, in particular, have considerable difficulty in recognizing and interpreting the subtleties of the lateral
Learning objectives
Outline
• Review fundamental anatomy, variations, and spaces routinely revealed on the lateral CXR
• • • • • •
• Correlate the perspective the lateral view provides with that provided by multiplanar CT • Reinforce an appreciation of the value of the lateral chest radiograph
Trachea Retrotracheal space (Raider triangle) Large airways A t i and Arteries d veins i “Three clear spaces” Inferior hilar window
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Trachea
Trachea
• Easily recognizable
• Posterior tracheal stripe
• Anterior tracheal stripe – Appreciated only on occasion • Mediastinal fat • Air/lung – May not be visibly altered even in the presence of extensive pretracheal pathology
Trachea
Trachea
• Posterior tracheal stripe
• Posterior tracheal stripe
– Outlined posteriorly by air in right lung or esophageal lumen and anteriorly by air in tracheal lumen – Abnormal appearance • > 5.5 mm • Persistently thickened on serial radiographs
– Outlined posteriorly by air in right lung or esophageal lumen and anteriorly by air in tracheal lumen – Abnormal appearance • > 5.5 mm • Persistently thickened on serial radiographs
Trachea
Retrotracheal space
• Posterior tracheal stripe
• Retrotracheal space (“Raider triangle”)
– Outlined posteriorly by air in right lung or esophageal lumen and anteriorly by air in tracheal lumen – Abnormal appearance • > 5.5 mm • Persistently thickened on serial radiographs
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– Outlined posteriorly by air in right lung or esophageal lumen and anteriorly by air in tracheal lumen – Variable appearance, 1-5 mm • Posterior tracheal wall only: thin line • Posterior tracheal wall, intervening tissue, collapsed esophagus: thicker stripe or band
– Boundaries • Anterior posterior tracheal wall-right lung • Posterior thoracic vertebral bodies • Superior thoracic inlet • Inferior aortic arch-left lung – Size varies with age, body habitus, and lung inflation
Retrotracheal space
Retrotracheal space
Retrotracheal space
• Retrotracheal space (“Raider triangle”)
• Retrotracheal space (“Raider triangle”)
– Boundaries – Contents à Esophagus à Left recurrent laryngeal nerve à Thoracic duct à Lymph nodes à Lungs
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Retrotracheal space
– Boundaries – Contents – Pathology à Congenital vascular lesions à Acquired vascular lesions à Esophageal abnormalities à Mediastinal masses à Infections
Retrotracheal space congenital vascular lesions left aortic arch with aberrant right subclavian artery right aortic arch with aberrant left subclavian artery double aortic arch
acquired i d vascular l llesions i aneurysm of aberrant subclavian artery aortic aneurysm
infections tuberculous/pyogenic mediastinitis abscess
Franquet et al. Radiographics 2002; 22:S231-246
esophageal abnormalities Zenker diverticulum achalasia esophageal atresia duplication cyst esophageal esop agea leiomyoma y esophageal carcinoma
mediastinal masses intrathoracic goiter schwannoma /neurofibroma hemangioma lymphatic malformation hematoma
Retrotracheal Space
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Large airways
Large airways
McComb. J Thorac Imaging 2002; 17:58-69
Large airways
Large airways
• Right upper lobe bronchus (RUL) – Projects between aortic arch and left pulmonary artery
Courtesy of Robert Suh, M.D.
Large airways
Large airways
• Right upper lobe bronchus (RUL)
• Right upper lobe bronchus (RUL)
– Anterior margin closely related to RUL artery – Superior margin closely related to azygous vein
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– Inconsistently visualized – Increasing conspicuity Æ contiguous pathology
Large airways
• Left main-upper lobe continuum (LULC)
• Left main-upper lobe continuum (LULC)
– Consistently visualized distinct landmark – Projects below left pulmonary artery
– Projects below left pulmonary artery (LPA) • LPA (superior and posterior) • Left superior pulmonary vein (inferior and anterior)
Large airways
Large airways
• Left main-upper lobe continuum (LULC)
• Left main-upper lobe continuum (LULC)
– Continuum along left mainstem into LUL bronchus • Variable in size and shape • Occasionally, round lucency within round lucency
– Continuum along left mainstem into LUL bronchus • Variable in size and shape • Occasionally, round lucency within round lucency
Large airways
Large airways
• Left main-upper lobe continuum (LULC)
• Posterior wall of bronchus intermedius
– Continuum along left mainstem into LUL bronchus • Variable in size and shape • Occasionally, round lucency within round lucency
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Large airways
– Intermediate stem line – Continuous with right mainstem bronchus, terminating at origin of RLL superior segmental bronchus – Approximated posteriorly by azygoesophageal recess – Typically projects over LULC • Foretells rotation
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Large airways
Large airways
• Posterior wall of bronchus intermedius
• Posterior wall of bronchus intermedius
– Intermediate stem line – Continuous with right mainstem bronchus, terminating at origin of RLL superior segmental bronchus – Approximated posteriorly by azygoesophageal recess – Typically projects over LULC • Foretells rotation
Large airways
Large airways
• Posterior wall of bronchus intermedius
• Posterior wall of bronchus intermedius
– Intermediate stem line – Continuous with right mainstem bronchus, terminating at origin of RLL superior segmental bronchus – Approximated posteriorly by azygoesophageal recess
– Abnormal > 3 mm
Large airways
Large airways
• Posterior wall of bronchus intermedius
• Posterior wall of bronchus intermedius
– Abnormal > 3 mm
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– Intermediate stem line – Continuous with right mainstem bronchus, terminating at origin of RLL superior segmental bronchus – Approximated posteriorly by azygoesophageal recess – Typically projects over LULC • Foretells rotation
– Abnormal > 3 mm
Arteries and veins
• Posterior wall of bronchus intermedius
• Left pulmonary artery (LPA)
– Abnormal > 3 mm
– Short posterosuperior and lateral mediastinal course – When outlined superiorly by air, resembles “miniature aortic arch”
Arteries and veins
Arteries and veins
• Left pulmonary artery (LPA)
• Left pulmonary artery (LPA)
– Short posterosuperior and lateral mediastinal course – When outlined superiorly by air, resembles “miniature aortic arch”
– Obscured superior border • AP window lymphadenopathy – Lobulated posterior border • Hilar lymphadenopathy
Arteries and veins
Arteries and veins
• Left pulmonary artery (LPA)
• Left pulmonary artery (LPA)
– Obscured superior border • AP window lymphadenopathy – Lobulated posterior border • Hilar lymphadenopathy
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Large airways
– Obscured superior border • AP window lymphadenopathy – Lobulated posterior border • Hilar lymphadenopathy
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Arteries and veins
Arteries and veins
• Right pulmonary artery (RPA)
• Right pulmonary artery (RPA)
– In actuality, “right hilar vascular opacity” – Conglomerate of pulmonary arteries and veins
– – – – –
Longer lateral mediastinal course than LPA Divides at the edge of the mediastinum RPA = upper aspect of right hilar vascular opacity Interlobar artery = lower aspect of rt hilar vasc opacity Poorly marginated secondary to branching and lack of adjacent lung
Arteries and veins
Arteries and veins
• Right pulmonary artery (RPA)
• Right pulmonary artery (RPA)
– – – – –
Longer lateral mediastinal course than LPA Divides at the edge of the mediastinum RPA = upper aspect of right hilar vascular opacity Interlobar artery = lower aspect of rt hilar vasc opacity Poorly marginated secondary to branching and lack of adjacent lung
– – – – –
Longer lateral mediastinal course than LPA Divides at the edge of the mediastinum RPA = upper aspect of right hilar vascular opacity Interlobar artery = lower aspect of rt hilar vasc opacity Poorly marginated secondary to branching and lack of adjacent lung
Arteries and veins
Arteries and veins
• Right pulmonary artery (RPA)
• Right ventricular outflow tract • Ascending thoracic aorta
– Enlargement of right hilar vascular opacity with lobulated contour • Hilar lymphadenopathy
• Variable visibility – Approximation of lung and fat to anterior borders – Alignment with path of x-ray beam
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Arteries and veins
• Right ventricular outflow tract • Ascending thoracic aorta
• Right ventricular outflow tract • Ascending thoracic aorta
Arteries and veins
Arteries and veins
• Inferior vena cava (IVC)
• Inferior vena cava (IVC)
– Occasionally, anterior wall also outlined by lung
– Occasionally, anterior wall also outlined by lung
Arteries and veins
Arteries and veins
• Left brachiocephalic vein
• • • •
– Retromanubrial opacity
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Arteries and veins
Superior vena cava Right brachiocephalic vein Innominate artery Right subclavian artery
• Composite S-shaped opacity on lateral radiograph
McComb. J Thorac Imaging 2002; 17:58-69
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Arteries and veins
Three clear spaces
• • • •
• “Spine sign”
Superior vena cava Right brachiocephalic vein Innominate artery Right subclavian artery
– Increasing lucency as progress down thoracic vertebral bodies • Less soft tissue attenuation in l lower chest h t wallll compared d tto upper chest wall/shoulders
McComb. J Thorac Imaging 2002; 17:58-69
Three clear spaces
Three clear spaces
• “Spine sign”
• “Spine sign”
– Two types of abnormalities • Localized opacity with discrete edge – Lung mass or consolidation – Mediastinal mass • Increased density without edge – Pleural thickening/disease – Lower lobe collapse
Three clear spaces
Three clear spaces
• “Spine sign”
• Anterior clear space
– Two types of abnormalities • Localized opacity with discrete edge – Lung mass or consolidation – Mediastinal mass • Increased density without edge – Pleural thickening/disease – Lower lobe collapse
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– Two types of abnormalities • Localized opacity with discrete edge – Lung mass or consolidation – Mediastinal mass • Increased density without edge – Pleural thickening/disease – Lower lobe collapse
– Increasing lucency as progress superiorly from the densest portion of the heart • Decreasing width of anterior mediastinum, b i i att PA/ beginning PA/ascending di aorta t llevell tto SVC/brachocephalic veins – Variable degree of lucency • Amount of lung protruding behind manubrium • Women have decreased retrosternal lucency
Three clear spaces
• Anterior clear space
• Anterior clear space
– Increasing lucency as progress superiorly from the densest portion of the heart • Decreasing width of anterior mediastinum, b i i att PA/ beginning PA/ascending di aorta t llevell tto SVC/brachocephalic veins – Variable degree of lucency • Amount of lung protruding behind manubrium • Women have decreased retrosternal lucency
– Increasing lucency as progress superiorly from the densest portion of the heart • Decreasing width of anterior mediastinum, b i i att PA/ beginning PA/ascending di aorta t llevell tto SVC/brachocephalic veins – Variable degree of lucency • Amount of lung protruding behind manubrium • Women have decreased retrosternal lucency
Three clear spaces
Three clear spaces
• Anterior clear space
• Retrocardiac clear space
– Opacification with our without discrete edge • Anterior mediastinal mass • Lung mass or consolidation
– Increasing lucency as progress inferiorly from between the posterior border of heart and anterior vertebral bodies (infrahilar) • Decreasing D i width idth off mediastinum di ti – Esophagus and azygous vein – Air-filled right lower lobe (azygoesophageal recess)
Three clear spaces
Three clear spaces
• Retrocardiac clear space
• Retrocardiac clear space
– Increasing lucency as progress inferiorly from between the posterior border of heart and anterior vertebral bodies (infrahilar) • Decreasing D i width idth off mediastinum di ti – Esophagus and azygous vein – Air-filled right lower lobe (azygoesophageal recess)
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Three clear spaces
– Opacification with or without discrete edge • Lung or mediastinal mass (m. common hiatal hernia) • Lung consolidation (edge represents major fissure)
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Inferior hilar window
Inferior hilar window
• Sub-area of retrocardiac clear space
• Sub-area of retrocardiac clear space
– Avascular area along anteroinferior hilar composite – Boundaries • Right middle lobe bronchus • Left lower lobe bronchus – Devoid of nodular opacities > 1 cm
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– Avascular area along anteroinferior hilar composite
Inferior hilar window
Inferior hilar window
Inferior hilar window
Inferior hilar window
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Inferior hilar window
Inferior hilar window
Courtesy of Robert Suh, M.D.
Courtesy of Robert Suh, M.D.
Conclusions
Inferior hilar window
• The lateral chest radiograph provides a perspective that significantly enhances the evaluation for thoracic disease • Awareness of routinely visualized anatomic structures and spaces should facilitate improved interpretation of conventional chest radiographs
Courtesy of Robert Suh, M.D.
Posttest question
References
• On a properly positioned (i.e. non-rotated) lateral radiograph, the posterior wall of the bronchus intermedius projects over which structure?
1) Franquet T, Erasmus JJ, Gimenez A, et al. The retrotracheal space: normal anatomic and pathologic appearances. Radiographics 2002; 22:S231-S246. 2) McComb BL. The chest in profile. J Thorac Imaging 2002; 17:58-69. 3) Park CK, Webb WR, Klein JS. Inferior hilar window. Radiology 1991; 178:163-168. g D. Lateral chest radiograph: g p a systematic y approach. pp Acad Radiol 4)) Feigin 2010; 17:1560-1566. 5) Landay MJ. Anterior clear space: how clear? How often? How come? Radiology 1994; 192:165-169.
a) b) c) d)
Right upper lobe bronchus Right hilar vascular opacity Left main-upper lobe continuum Left pulmonary artery
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