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Part 2 book “Chest radiology - The esentials” has contents: Upper lung disease, infection, and immunity, atelectasis, peripheral lung disease, airways, unilateral hyperlucent hemithorax, neoplasms of the lung, congenital lung disease, pulmonary vasculature disease, congenital and acquired cardiac disease, thoracic aorta.
LEARNING OBJECTIVES 1. List an appropriate differential diagnosis for upper lung disease seen on chest radiography or computed tomography (CT) 2. Describe the radiographic classification of sarcoidosis 3. State the three most common locations (Garland triad) for adenopathy to occur in the chest of patients with sarcoidosis 4. List four common etiologies of “eggshell” calcified lymph nodes in the chest 5. Recognize progressive massive fibrosis secondary to silicosis on chest radiography and CT 6. Recognize and describe the typical appearance of cystic fibrosis on chest radiography and CT 7. Describe the radiologic manifestations of primary pulmonary tuberculosis 8. Name the most common segmental sites of involvement for reactivation tuberculosis in the lung 9. Define a Ghon lesion (calcified pulmonary parenchymal granuloma) and Ranke complex (calcified node and Ghon lesion); recognize both on a chest radiograph and CT and describe their significance 10. Suggest the possibility of radiation as a cause of new upper lung opacification on a chest radiograph of a patient with evidence of mastectomy and/or axillary node dissection or known head and neck cancer 11. Describe the acute and chronic phases of radiation-caused changes in the lungs, including the time course and typical chest radiograph and CT appearances 12. Recognize the typical appearance of irregular lung cysts on chest CT of a patient with Langerhans cell histiocytosis 13. Name the major categories of disease that cause chest radiographic or CT abnormalities in the immunocompromised patient 14. Other than typical bacterial infection, name two important infections and two important neoplasms to consider in patients with acquired immunodeficiency syndrome (AIDS) and chest radiographic or CT abnormalities 15. Describe the typical chest radiographic and CT appearances of Kaposi sarcoma 16. Describe the chest radiographic and CT appearances of Pneumocystis jiroveci pneumonia 17. Name four important etiologies of hilar and mediastinal lymphadenopathy in patients with AIDS 18. Describe the time course and chest radiographic appearance of a blood transfusion reaction 19. Describe the chest radiographic and CT appearances of a miliary pattern and provide a differential diagnosis 20. Name and describe the types of pulmonary Aspergillus disease 21. Identify an intracavitary fungus ball on chest radiography and CT 22. Name the most common pulmonary infections that occur after solid organ (e.g., liver, renal, lung, cardiac) and bone marrow transplantation 23. Describe the chest radiographic and CT findings of posttransplant lymphoproliferative disorders Pulmonary infections are a major cause of morbidity and mortality, especially in immunocompromised patients Immunocompromised patients have altered immune mechanisms and are predisposed to opportunistic infections Numerous factors are associated with an immunocompromised state, including but not limited to diabetes; renal or liver failure; advanced age; bone marrow or solid organ transplantation; acquired immunodeficiency syndrome (AIDS); presence of access lines (e.g., intravenous lines, endotracheal tubes, chest tubes); splenectomy, hospital environment (predisposing to nosocomial pneumonia); underlying malignancy; drug therapy (e.g., steroids, chemotherapy); and immune deficiencies (e.g., hypogammaglobulinemia) Some of the clinically important infections and other diseases seen in immunocompetent and immunocompromised patients tend to have an upper lung–predominant distribution (e.g., mycobacterial and fungal disease) Recognition of an upper lung distribution of disease helps the clinician to form an appropriate differential diagnosis This chapter begins with a discussion of upper lung disease, including infectious and noninfectious causes, and continues with a review of the disorders that occur in immunocompromised individuals and their radiographic appearances UPPER LUNG DISEASE Upper lung refers to the upper one-third of the lung, which includes the majority of the upper lobes and the uppermost portion of the superior segments of the lower lobes In the normal upright lung, blood flow and ventilation predominate in the lung base; in many lung disorders however, the greatest degree of abnormality occurs in the upper lung Alterations in ventilation–perfusion, lymphatic flow, metabolism, and mechanics are proposed as pathogenic factors in upper lung localization of lung disease (1) Two mnemonics, “SHRIMP” and “CASSET,” can be used to recall common and uncommon disorders occurring in the upper lungs (Table 10.1) Because it may be difficult to appreciate a predominantly upper lung distribution of disease on chest radiography, it is useful to consider the differential diagnoses given in Table 10.1, even if the disease appears diffuse, any time the upper lungs are as affected as much or more than the middle and lower lungs SARCOIDOSIS Sarcoidosis is a common systemic disease of unknown etiology characterized by widespread development of noncaseating granulomas These granulomas are nonspecific and resemble those in many other granulomatous processes, except for tuberculosis (TB), a disease in which caseous necrosis of granulomas is usually seen Sarcoidosis is 10 times more common in African-Americans than in Caucasians (2) Most patients who present with sarcoidosis are between the ages of 20 and 40, but the disease occurs as early as year and as late as 80 years of age (3) The disease is 2 to 3 times more common in African-American women than in African-American men (3) The lung is the most commonly involved organ in patients with sarcoidosis and accounts for most of the morbidity and mortality, with an overall mortality rate between 2.2% and 7.6% (3) Table 10.1 UPPER LUNG DISEASE “SHRIMP” Sarcoidosis Histiocytosis, Langerhans cell Radiation pneumonitis (cancers of head/neck and breast) Infection (tuberculous, fungal) Metastasesa Pneumoconiosesb (silicosis, coal miner’s) “CASSET” Cystic fibrosis Ankylosing spondylitis Silicosis Sarcoidosis Eosinophilic granulomatosis (Langerhans cell histiocytosis) Tuberculous, fungal infection a See Chapter 7 See Chapter 3 b Table 10.2 CLASSIFICATION OF SARCOIDOSIS ON CHEST RADIOGRAPHY I II III IV Normal chest radiograph Hilar or mediastinal nodal enlargement only Nodal enlargement and parenchymal disease Parenchymal disease only End-stage lung (pulmonary fibrosis) Sarcoidosis can be classified according to its appearance on the chest radiograph (Table 10.2) (4) Patients commonly, but not necessarily, progress through each class, and the class at presentation can, but does not always, correlate with prognosis (5) Forty-five percent to 65% of patients are class I at the time of presentation Lymphadenopathy is the most common intrathoracic manifestation of sarcoidosis and occurs in 75% to 80% of patients at some point in their illness (6) The classic pattern of lymphadenopathy is bilateral hilar and right paratracheal nodal enlargement, the so-called Garland triad or 1-2-3 sign (Figs 10.1 and 10.2), although any mediastinal nodes can be and frequently are involved The hilar lymph nodes are usually symmetric in appearance and can be massively enlarged (“potato nodes”) but are usually clear of the cardiac borders, a feature that helps distinguish sarcoidosis from lymphomatous lymphadenopathy, as the latter usually abuts the cardiac margins Of patients with class I disease at initial examination, about 60% go on to complete resolution (7), with parenchymal disease occurring in the remaining patients Nodal calcification is seen in up to 20% of cases (8), and in some of these cases (approximately 5%), the calcification is of a peripheral “eggshell” pattern (Figs 10.3 and 10.4) Eggshell calcification is largely limited to sarcoidosis and silicosis, but it can be seen in other disorders (Table 10.3) (9) FIG 10.1 • Sarcoidosis Posteroanterior (PA) chest radiograph of a 31-year-old woman with class I sarcoidosis shows right paratracheal (arrowheads) and bilateral hilar (arrows) lymphadenopathy This pattern of lymphadenopathy is classic for sarcoidosis and is referred to as the 1-2-3 sign or Garland triad FIG 10.2 • Sarcoidosis A: CT of a 23-year-old woman shows ill-defined nodules in a bronchovascular distribution (arrow) in the right upper lobe B: CT with mediastinal windowing shows right hilar lymphadenopathy (arrow) C: CT at the level of the inferior pulmonary veins shows left hilar lymphadenopathy (arrow) D: CT at the level of the lower lobe pulmonary arteries shows subcarinal lymphadenopathy (arrow) Parenchymal disease is seen on chest radiography at the time of presentation in approximately half of patients with sarcoidosis Radiographic patterns of parenchymal disease include reticulonodular opacities, ill-defined opacities that have an appearance of alveolar filling, large nodules, and lung fibrosis Reticulonodular opacities are the most common pattern, seen in 75% to 90% of patients with parenchymal disease; the opacities are usually bilaterally symmetric with a distribution predominantly in the middle and upper lungs (10) (Figs 10.5 and 10.6) In 10% to 20% of patients, opacities with airspace features develop, which can be ill-defined or focal, nodular, and well-defined The term alveolar sarcoid refers to this pattern, although the “airspace” disease represents an interstitial process that compresses and obliterates alveoli Alveolar sarcoid generally consists of bilateral, multifocal, poorly defined opacities showing a predilection for the peripheral lungs (11) (Fig 10.7) The peripheral distribution is particularly well seen with computed tomography (CT) FIG 10.3 • Sarcoidosis CT shows precarinal lymphadenopathy with rim calcification (arrow) This pattern of calcification is referred to as “eggshell” calcification and is seen in approximately 5% of patients with sarcoidosis Sarcoid granulomas may resolve completely or heal by fibrosis Pulmonary fibrosis occurs in approximately 20% of patients with sarcoidosis, and the radiologic features are considered by some authors to be almost pathognomonic The findings consist of permanent, coarse, linear opacities radiating laterally from the hilum into adjacent upper and middle lungs Bullae can form in the upper lungs The hila are pulled upward and outward, and vessels and fissures are distorted The fibrosis is occasionally so severe that massive parahilar opacities in the middle and upper lungs, resembling those of progressive massive fibrosis of silicosis, are seen (Fig 10.8) CT can define the anatomic location of parenchymal sarcoid granulomas much more accurately (12–14) The most common finding of sarcoidosis on CT is multiple, 1- to 5-mm nodules, usually with irregular margins, in a perilymphatic distribution (bronchovascular margins, along interlobular septa, subpleurally, and in the center of secondary pulmonary lobules) (Fig 10.9) Septal thickening from sarcoidosis has a beaded appearance, a feature that helps distinguish it from pulmonary edema, in which the septal thickening is typically smooth Patchy ground-glass opacities are seen in about 50% of patients with sarcoidosis and rarely may be the only CT abnormality (Fig 10.10) Fibrosis is better characterized on CT than on chest radiography CT can show findings of sarcoidosis when the chest radiograph is normal, and patients can have a normal CT study yet have sarcoidosis proved by lung biopsy (13) FIG 10.4 • Sarcoidosis A: PA chest radiograph of a 37-year-old man shows bilateral upper lobe nodular disease and hilar enlargement (class II) B: CT shows nodules of varying size along the fissures (straight solid arrow) and bronchovascular bundles (dashed arrow) and in a subpleural location (curved solid arrow) C: CT with mediastinal windowing shows central calcification of right paratracheal lymph nodes (arrow) D: CT at a lower level shows calcification of right hilar nodes (arrow) Table 10.3 COMMON CAUSES OF “EGGSHELL” CALCIFICATION OF LYMPH NODES IN THE CHEST “SIT” Sarcoidosis Silicosis Infection (tuberculous, fungal) Treated lymphoma Fungus balls (mycetomas) can develop in cystic areas that develop from sarcoidosis, and sarcoidosis is the second most common predisposing condition (afterTB) leading to the development of mycetoma (15) Hemoptysis resulting from mycetoma formation can be life-threatening Mycetomas occur in the upper lobes and should be suspected when new opacities are seen in an area of chronic cystic or bullous disease, especially when they are accompanied by new apical pleural or extrapleural opacity on chest radiography There are myriad other atypical features of sarcoidosis, including pleural effusions, pleural thickening, cavitary nodules, bronchostenosis, pulmonary artery hypertension from periarterial granulomatosis (Fig 10.11), cor pulmonale, and pneumothorax from chronic fibrosis ... classic for sarcoidosis and is referred to as the 1 -2 -3 sign or Garland triad FIG 10 .2 • Sarcoidosis A: CT of a 23 -year-old woman shows ill-defined nodules in a bronchovascular distribution (arrow) in the right upper lobe... manifestation of sarcoidosis and occurs in 75% to 80% of patients at some point in their illness (6) The classic pattern of lymphadenopathy is bilateral hilar and right paratracheal nodal enlargement, the so-called Garland triad or 1 -2 -3 sign (Figs 10.1 and 10 .2) , although any mediastinal nodes can be and frequently are...11. Describe the acute and chronic phases of radiation-caused changes in the lungs, including the time course and typical chest radiograph and CT appearances 12. Recognize the typical appearance of irregular lung cysts on chest