easy to miss on chest radiographs

8/8/2019 Easy to Miss on Chest Radiographs

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The chest radiograph is one of the most

commonly ordered radiographs by healthcare

providers and is frequently first viewed by non-

radiologists. Although there are many diseaseprocesses that are very obvious at first glance

on chest radiographs, healthcare providers must

be careful not to miss more subtle findings. The

image shows a solitary pulmonary nodule(arrow) abutting the left upper mediastinum.


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Sarcoidosis is a multisystem granulomatous

disease that classically presents with pulmonary,

eye, or skin lesions. Characteristic pulmonary

radiographic appearances are present in 60%-70% of individuals with sarcoidosis. Bilateral

symmetric hilar lymphadenopathy (arrows) is the

most common pulmonary radiographic finding.

In more advanced (Stage 4) disease, fibrosis,hilar retraction, decreased lung volumes, and

honeycombing may develop.


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Pulmonary hypertension develops as a result ofincreased pulmonary artery pressure and vascularresistance. Primary pulmonary hypertension usuallyaffects young women and is a disease of unknown

etiology. Secondary pulmonary artery hypertension canbe due to precapillary (eg, left-to-right shunt), capillary(eg, veno-occulsive disease), or postcapillary (eg,chronic lung disease) causes. The most commonfindings on chest radiograph are enlarged pulmonary

arteries (arrow) that taper distally (peripheral pruning). Adilated right ventricle with a decreased retrosternalspace may also be seen on lateral images.


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Pancoast tumors are pulmonary neoplasms located inthe superior sulcus of the lung. They are predominantlynon-small cell carcinomas, particularly of the squamouscell histology. They characteristically cross the pleural

barrier to invade the chest wall, brachial plexus, andsuperior sympathetic ganglion (resulting in Horner'ssyndrome). On chest radiographs, they may appear asunilateral apical opacity (arrow) or apical asymmetry.Local rib destruction, particularly the first rib, may also be

present. Lordotic chest views may be helpful to clarify asuspected lesion.


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Asbestos-related disease is caused by inhalation of asbestos fibers,typically from industrial or occupational exposures. The chestradiograph findings of bilateral calcified pleural plaques over thediaphragmatic, peripheral, or mediastinal pleura (white arrows) isindicative of prior asbestos exposure. Noncalcified pleural plaquesare not readily appreciated on chest radiograph but fully displayedon computed tomography. Progression of asbestos-related diseaseto involve the lung parenchyma is known as asbestosis. Thispredominantly affects the interstitial compartment of the lung andmanifests as increased interstitial markings, coarse parenchymalbands, rounded atelectasis (red arrows), and parenchymal distortionon chest radiographs. The appearance of pleural effusion --

particularly if associated with enlarging pleural mass and localizedpain -- is indicative of development of a mesothelioma.


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Unilateral pleural thickening is the classic finding onchest radiographs in patients with malignantmesothelioma. The pleural thickening may be eitherplaque-like or nodular. Pleural effusions may obscure thepleura, making it difficult to evaluate the thickness;however, the fissures may also become thickened andirregular in contour, which can aid in diagnosis. Thepresence of calcified pleural plaques indicates previousasbestos exposure, which is a risk factor for thedevelopment of mesothelioma. The image shown

demonstrates thickening of the left lateral pleura (arrow)with lobulation and effusion. Other potential causes ofunilateral pleural thickening are empyema, trauma,postoperative scarring, and metastatic disease.


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Pulmonary aspergillosis is a fungal infection by theAspergillusspecies, most commonlyAspergillus fumigatus. There are 4 distinctforms of pulmonary aspergillosis: allergic bronchopulmonaryaspergillosis (ABPA), aspergilloma, chronic necrotizing aspergillosis,and angioinvasive aspergillosis. Chest radiograph findings of ABPAinclude lobar infiltrates, perihilar 'glove-like' tubular shadowsrepresenting mucus-filled bronchiectasis, and tram-line bronchialwalls due to edema. The characteristic features of an aspergillomaare a round mass with an adjacent crescent-shaped air space(arrow). The fungal ball itself may be freely mobile and move whenthe patient changes position. Chronic necrotizing aspergillosis mayappear as segmental areas of consolidation, predominately in the

upper lobes, that progress toward cavitation. Angioinvasiveaspergillosis most commonly appears as patchy areas ofconsolidation with multiple nodules and peripheral wedge-shapedlesions due to hemorrhagic infarcts.


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A solitary pulmonary nodule is defined as a single discretepulmonary opacity surrounded by normal lung and not associatedwith adenopathy or atelectasis. The list of potential differentialdiagnoses is extensive and broadly includes benign and malignantneoplasms, infections, noninfectious granulomas, developmentallesions, vascular lesions, and other systemic processes. Althoughthe exact etiology may not be discernable on a chest radiograph,failure to detect a lesion and obtain appropriate follow-up can lead tosignificant morbidity and mortality for the patient. Key features toidentify are nodule size, location, growth rate, margin characteristics,cavitation, and calcification. Factors favoring malignancy are growthover time, large size, irregular or spiculated margin, and upper lobe

location. It may be easy to miss a lesion that overlaps the ribs orclavicles. The image shown is from an individual with a solitarypulmonary nodule (arrow) found to be a pulmonary ateriovenousmalformation.


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Tracheal stenosis is a narrowing of the trachea that maybe caused by chronic inflammatory disease, neoplasm,trauma, iatrogenic, and extrinsic compression fromlesions such as intrathoracic goiter (shown). On chest

radiographs, the trachea and mainstem bronchi canreadily be assessed for changes in caliber. Theradiograph may also provide clues as to the cause ofstenosis, such as tracheal deviation or a widenedmediastinum, or other potential etiologies for shortness

of breath, such as an aspirated foreign body. The imageshown is of a patient with a large intrathoracic goiterproducing a widened mediastinum (white arrows) withnarrowing of the trachea (black arrows).


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Cavitary lung lesions on chest radiographs can be theresult of an abscess, tuberculosis, carcinoma, Wegener'sgranulomatosis, metastatic cancer, or septic emboli. Keyfeatures to identify are size, wall thickness, air-fluid

levels, and location as this may provide clues as to thepotential etiology of the lesion. Lateral radiographs maybe needed to help confirm location. Abscesses typicallyhave thick walls and may have air/fluid levels.Metastases are typically thin-walled but may have a

variable appearance. Wegener's granulomatosis andseptic emboli are typically smaller lesions. The imageshows a thin-walled cavitary lesion without air-fluid level(arrow) in a patient with primary tuberculosis


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Osteomyelitis is an infection of the bone and bonemarrow. It may be easily missed on chest radiographs ifone does not pay careful attention to the bones inaddition to the lung fields. Typical findings of acute

osteomyelitis on plain radiographs are soft tissueswelling, periosteal reaction, cortical irregularity, anddemineralization. In chronic osteomyelitis, there is thick,irregular, sclerotic bone with radiolucencies and anelevated periosteum. The image shown is from a patient

with chronic osteomyelitis of the left clavicle with bonyexpansion, sclerosis, and periosteal reaction (arrow).Note the size difference compared to the right clavicle.


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Primary and metastatic cancer to the bones maybe evident on chest radiographs. Boney lesionsmay be sclerotic or lytic and can give clues as tothe etiology. Common malignancies giving rise

to sclerotic metastasis are prostate cancer,breast cancer, and lymphoma, while commonmalignancies giving rise to lytic metastasis arerenal cell cancer, multiple myeloma, and thyroidcancer. The image shown is from a chest

radiograph and reveals a permeative mixed lyticand sclerotic process in the left clavicle (arrow)secondary to malignant lymphoma.


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Compression fractures of the thoracic spine occurwhenever the spinal column is subjected to forces thatexceed its strength and stability. They may be firstdetected on chest radiographs by carefully evaluating

the vertebral bodies. Typical findings on a plainradiograph for anterior compression fractures includecortical impaction, loss of vertical height, buckling of theanterior cortex, trabecular compaction, and endplatefracture. Lateral radiographs may provide better views of

the spinal architecture. The image shown demonstrateskyphosis of the thoracic spine with an osteoporoticfracture of the T8 vertebral body (arrow).


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Malignant mesothelioma and localized fibroustumor of the pleura are primary pleuralneoplasms. Localized fibrous tumor of the pleurais a benign neoplasm of the pleura, not

associated with asbestos exposure. Typicalfindings on chest radiographs are a well-circumscribed, homogeneous soft-tissue massclosely related to the pleura. Lesions may befound anywhere along the lung periphery

(shown), pulmonary fissures, mediastinum, ordiaphragm. Large lesions may be confused forlobar consolidation.


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Unilateral hyperlucent lung may be the result ofSwyer-James syndrome, pneumothorax,obstructive emphysema, or pulmonary

embolism. Hyperlucency is typically the result ofalveolar distension (air retention) and/or reducedarterial flow. Swyer-James syndrome is amanifestation of postinfectious obliterativebronchiolitis found in children. On chest

radiograph, the ipsilateral lung is hyperlucentand overexpanded (left lung), compared with thecontralateral lung, which is smaller (shown).


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easy to miss on chest radiographs

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