Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

40 results found
Article

Echogenic fetal lung lesions

Echogenic fetal lung lesions on antenatal ultrasound can be detected in a number of situations. They include: Airway obstructions: lung are often enlarged and echogenic bilaterally congenital high airways obstruction syndrome (CHAOS) tracheal atresia congenital tracheal stenosis laryngeal a...
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Eggshell calcification

Eggshell calcification refers to fine calcification seen at the periphery of a mass, and usually relates to lymph node calcification. In 1967 Jacobsen and Felson published criteria to help "avoid over-reading of the incidental circumferential concentrations of calcium and to eliminate conf...
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Eggshell calcification in thorax and mediastinum (mnemonic)

A helpful mnemonic for major causes of eggshell calcification in the thorax and mediastinum is:  A Silly Cool Sergeant Likes His Tubercular Blast Mnemonic A: amyloidosis S: silicosis C: coal workers' pneumoconiosis (CWP) S: sarcoidosis L: lymphoma: (postirradiation Hodgkin disease) H: hi...
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Ehlers-Danlos syndrome

Ehlers Danlos syndrome comprises a heterogenous group of collagen disorders (hereditary connective tissue disease). Epidemiology There is a recognised male predominance. Clinical presentation Clinically manifests by skin hyperelasticity and fragility, joint hypermobility and blood vessel fra...
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Eisenmenger syndrome

Eisenmenger syndrome is a complication of an uncorrected high-flow, high-pressure congenital heart anomaly leading to chronic pulmonary arterial hypertension and shunt reversal. Epidemiology In general the shunts that lead to Eisenmenger syndrome share are high pressure and high flow 3. As suc...
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Elastofibroma dorsi

Elastofibroma dorsi is a benign soft-tissue tumour with a characteristic location and imaging appearance. Epidemiology It is more frequently seen in older women, with a reported female predilection of 5-13:1. The estimated mean age at diagnosis around 65-70 years. Clinical presentation Elast...
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Elevated diaphragm

Elevated diaphragm refers to the symmetrical elevation of both domes of the diaphragm. Pathology Causes There is some overlap with causes of an elevated hemidiaphragm.  Technical  supine position poor inspiratory effort Patient factors obesity pregnancy Diaphragmatic pathology paralys...
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Elevated hemidiaphragm

Elevated hemidiaphragms can result from many causes: above the diaphragm 1 decreased lung volume atelectasis/collapse lobectomy/pneumonectomy pulmonary hypoplasia diaphragm 3-7 phrenic nerve palsy diaphragmatic eventration contralateral stroke: usually middle cerebral artery distribut...
Article

Eleventh rib

The atypical 11th rib is one of two floating ribs. Gross anatomy Osteology The 11th rib has a single facet on its head for articulation with the T11 vertebra. It has a short neck and no tubercle. The angle is slight. Its costal groove is shallow. The internal surface of this rib faces slightl...
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Eloesser flap

Eloesser flap is a single stage procedure for the treatment of severe pleural empyema, and involves a U-shaped incision and the resection of a number of subjacent posterolateral ribs. The U-shaped flap is then folded into the pleural space creating a permanent communication.  Unlike the Clagett...
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Empyema

Empyemas are purulent inflammatory collections within a body cavity. They are similar to abscesses, which arise within parenchymal tissue rather than occupying a pre-existing anatomical space. Terminology Colloquially, the term empyema is used to refer to thoracic empyemas but there are variou...
Article

Empyema necessitans

Empyema necessitans (also sometimes spelt as empyema necessitasis) refers to extension of a pleural infection out of the thorax and into the neighbouring chest wall and surrounding soft tissues, e.g. extension of an empyema outwith the pleural cavity. Pathology It may either occur due the viru...
Article

Empyema vs pleural effusion

An empyema can resemble a pleural effusion and can mimic a peripheral pulmonary abscess, although a number of features usually enable distinction between the two (see empyema vs lung abscess). Features that help distinguish a pleural effusion from an empyema include: Shape and locati...
Article

Empyema vs pulmonary abscess

Distinguishing between an empyema and a peripherally located pulmonary abscess is essential. Lung abscesses are usually managed with prolonged antibiotics and physiotherapy with postural drainage whereas an empyema usually requires percutaneous or surgical drainage. Radiographic features Plai...
Article

Endobronchial intubation

Endobronchial intubation is not infrequent and is a trivial diagnosis to make in most instances provided an adequately penetrated chest radiograph is obtained. The incidence of endobronchial intubation is greatest following emergency intubation.  Clinical presentation The main issue with intub...
Article

Endobronchial metastases

Endobronchial metastases (EBMs) are an uncommon form of intrathoracic metastases. They are much less common than intrapulmonary metastases. Clinical presenation The clinical presentation can vary and include haemoptysis cough post-obstructive pneumonitis from distal obstruction Pathology ...
Article

Endobronchial metastases (mnemonic)

Primary neoplasms which may result in endobronchial metastases may be memorized by utilizing the following mnemonic: kiss My RBC 1  Mnemonic Kiss: Kaposi sarcoma My: melanoma R: renal cell carcinoma B: breast cancer C: colorectal carcinoma, cervical carcinoma, carcinoid See also endobro...
Article

Endogenous lipoid pneumonia

Endogenous lipoid pneumonia, also known as idiopathic lipoid pneumonia, is of the of the two types of lipoid pneumonias. Please refer to the main article for a broad discussion, including clinical presentation, radiographic features, and treatment and prognosis.  Terminology There is the clas...
Article

Enlargement of the cardiac silhouette

Enlargement of the cardiac silhouette on chest x-ray can be due to a number of causes 1: cardiomegaly (most common cause by far) pericardial effusion anterior mediastinal mass prominent epicardial fat pad expiratory radiograph Recognising enlargement relies upon an understanding of the nor...
Article

Eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as the Churg-Strauss syndrome (CSS), is a small to medium vessel necrotising pulmonary vasculitis. It is also classified under the spectrum of eosinophilic lung disease and as a type of pulmonary angiitis and granulomatosis. ...
Article

Eosinophilic lung disease

Eosinophilic lung diseases are heterogenous group of disorders that are characterised by excess infiltration of the eosinophils within the lung interstitium and alveoli and are broadly divided into three main groups 1: idiopathic: unknown causes secondary: known causes eosinophilic vasculitis...
Article

Epicardial fat pads

Epicardial (pericardial) fat pads are normal structures that lie in the cardiophrenic, more so on the right. Unsurprisingly, they are more prominent in obese patients. Pathology They can be affected by fat necrosis (see: epipericardial fat necrosis).  Radiographic features Plain radiograph ...
Article

Epipericardial fat necrosis

Epipericardial fat necrosis is a rare self-limiting cause of an acute chest pain in an otherwise healthy individuals. It occurs within the mediastinum outside the pericardium. Clinical presentation The patient presents with an acute chest pain that may mimic other cardiopulmonary causes. It is...
Article

Episternal ossicles

Episternal (or suprasternal) ossicles are accessory bones and a normal variant of the sternum. They result from supernumerary ossification centers and are seen in ~4% (range 1-7%) of the population.  Gross anatomy Episternal ossicles are usually located posterior or superior to the superior bo...
Article

Epithelial-myoepithelial carcinoma of lung

Epithelial-myoepithelial carcinoma of lung is a very rare type of lung carcinomas of the salivary gland type. Pathology Diagnosis is based on the identification of myoepithelial cells, with spindle cells, clear cells, or plasmacytoid differentiation or a mixture of phenotypes, along with a var...
Article

Erdheim Chester disease: pulmonary manifestations

Pulmonary involvement in Erdheim Chester disease is an uncommon manifestation of Erdheim Chester disease. Epidemiology The lungs are affected in ~25% (range 20-35%) of cases 5.  Radiographic features HRCT chest Described findings include 1 symmetric reticular interstitial opacities smooth...
Article

Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell, non-familial multisystemic granulomatosis, with widespread manifestations and of highly variable severity. The most common presenting symptom is bone pain. Epidemiology Erdheim-Chester disease is a rare, non-inherited disease of midd...
Article

Evaluation of endotracheal tube position

Endotracheal tubes (ETT) are wide-bore plastic tubes that are inserted into the trachea to allow artificial ventilation. Tubes come in a variety of sizes and have a balloon at the tip to ensure that gastric contents are not aspirated into the lungs. Adult tubes are usually approximately 1 cm in ...
Article

Ewing sarcoma of the chest wall

Ewing sarcoma family of tumours (ESFT), also referred as Ewing sarcomas of the chest wall, are malignant tumours affecting children and young adults, originating either from the osseous structures or the soft tissues of the chest wall.  On imaging, they are usually characterised as a large extr...
Article

Expiratory HRCT

Expiratory HRCT is an useful method for detecting small airway obstructive disease in which the air remain trapped in the small airways even after the expiration and appear as mosaic attenuation. Indication Ideally the expiratory HRCT scan should be done in all obstructive airway diseases incl...
Article

External intercostal muscle

The external (or outermost) intercostal muscles are an important muscle of respiration. They number eleven on each side and are located in the intercostal space, expanding the transverse dimension of the thoracic cavity during inspiration. Gross anatomy The external intercostal muscles are the...
Article

Extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is used as modified pulmonary or cardiopulmonary bypass technique in those with severe cardiac +/- respiratory failure refractory to conventional ventilatory support and medical intervention 1,3. Sub types veno-arterial (VA) ECMO veno-venous (VV) ECM...
Article

Extralobar pulmonary sequestration

Extralobar pulmonary sequestration (ELS) is a subtype of pulmonary sequestration, the other type being intralobar pulmonary sequestration (ILS). Epidemiology It is usually encountered in infants, most being diagnosed before six months. It is more common in male (M:F 4:1). Pathology Extraloba...
Article

Extramedullary haematopoiesis

Extramedullary haematopoiesis (EMH) is a response to erythropoiesis failure in bone marrow. EMH occurs in haemoglobinopathies, myeloproliferative disorders, or bone marrow infiltration. EMH occurs most often in the spleen and liver and occasionally in the lymph nodes. Less common organs include ...
Article

Extrapleural air sign

The extrapleural air sign is one of the many signs of pneumomediastinum, and was first described by Lillard and Allen in 1965. It is defined as the presence the air between the parietal pleura and the diaphragm. On a lateral projection the air forms a radiolucent pocket of air posterior to the d...
Article

Extrapleural fat

Extrapleural fat is benign condition and refers to relaitve diffuse deposition of fat outside the parietal pleura. It can occur in various locations but typically occurs along the chest wall. It is a component of the loose connective tissue of the endothoracic fascia and is most abundant along t...
Article

Extrapleural fat sign

The extrapleural fat sign is an imaging feature which can be seen on CT under certain circumstances. It occurs from the inward displacement of an extrapleural fat stripe by an extrapleural fluid collection, extrapleural haematoma or extra pleural mass. The presence of the extrapleural fat sign i...
Article

Extrapleural haematoma

Extrapleural haematoma (EPH) is a rare situation, which usually occurs due to rib fracture or blunt chest injury. Pathology EPH results from accumulation of blood in the extrapleural space where the overlying extrapleural fat is displaced centrally. Aetiology common: injury to intercostal ar...
Article

Extrapleural sign

The extrapleural sign, described by Felson in 1973 1, refers to the appearance of a pulmonary opacity with oblique margins that taper slowly to the chest wall when the lesion is viewed tangentially to the x-ray beam. This appearance suggests that the lesion is extrapleural in nature, as opposed ...
Article

Exudate

An exudate is a collection that has a relatively high specific gravity and protein concentration. They occur as the result of an inflammatory process that either increases the permeability of the surrounding membrane or disrupts the ability of resorption of fluid. They may be secondary to: infe...

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