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.
1,794 results found
Article
Diffuse airway narrowing
Diffuse airway narrowing can occur from a number of pathologies; these include:
relapsing polychondritis
ulcerative colitis
amyloidosis: tracheobronchial
sarcoidosis
granulomatosis with polyangiitis
tracheopathia osteochondroplastica
various infections including
tracheobronchial papillom...
Article
Diffuse alveolar damage
Diffuse alveolar damage (DAD) is a common manifestation of drug-induced lung injury that results from necrosis of type II pneumocytes and alveolar endothelial cells.
Clinical presentation
Affected patients present with dyspnea, cough, and occasionally fever. Diffusion capacity of the lung for ...
Article
Diffuse alveolar hemorrhage
Diffuse alveolar hemorrhage (DAH) is a subset of diffuse pulmonary hemorrhage when bleeding is diffuse and directly into the alveolar spaces. It can occur in a vast number of clinical situations and can be life-threatening.
Pathology
Blood tends to fill alveolar spaces at multiple sites.
Etio...
Article
Diffuse ground-glass nodules
Diffuse ground-glass nodules can arise from many causes. These include:
infection
atypical infections (especially in immunosuppressed patients) 1,3
pneumocystis jirovecii pneumonia
cytomegalovirus pneumonia
pulmonary herpes simplex infection
pulmonary respiratory syncytial viral infection
...
Article
Diffuse ground-glass opacification
Diffuse or widespread ground-glass opacification/opacity carries a wide differential diagnosis 1-3:
diffuse alveolar disease
hydrostatic pulmonary edema
acute respiratory distress syndrome (ARDS)
diffuse alveolar hemorrhage
interstitial lung disease
hypersensitivity pneumonitis
connective...
Article
Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia
Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an extremely rare pulmonary disorder at the benign end of the neuroendocrine cells proliferation spectrum. It is mainly seen in non-smoker middle-age females with a history of chronic cough or asthma. On imaging, it is cha...
Article
Diffuse panbronchiolitis
Diffuse panbronchiolitis, also referred as diffuse Asian panbronchiolitis, is a form of bronchiolitis and is an idiopathic progressive inflammatory small airways obstructive lung disease.
Epidemiology
There is a striking predilection in the population from East Asia (e.g. Japan, Korea, China)....
Article
Diffuse pleural thickening
Diffuse pleural thickening refers to a morphological type of pleural thickening. It can occur from malignant as well as non-malignant causes, which include:
diffuse pleural fibrosis / fibrothorax 6
asbestos-related pleural disease: typically seen as a continuous sheet of pleural thickening oft...
Article
Diffuse pulmonary hemorrhage
Diffuse pulmonary hemorrhage (DPH) is a subtype of pulmonary hemorrhage where bleeding into the lung is diffuse. If the bleeding is into the alveolar spaces this can be further subclassified as diffuse alveolar hemorrhage (DAH).
Clinical presentation
While the exact presentation can vary is ha...
Article
Diffuse pulmonary lymphangiomatosis
Diffuse pulmonary lymphangiomatosis (DPL) is a rare condition characterized by diffuse proliferation of anastomosing lymphatic channels (lymphangiomas).
Epidemiology
There is no recognized gender predilection. It typically manifests in children and young adults.
Radiographic features
CT ches...
Article
Diffuse pulmonary meningotheliomatosis
Diffuse pulmonary meningotheliomatosis is a rare condition manifested by multiple minute pulmonary meningothelial nodules (MPMNs) scattered throughout the lungs.
Epidemiology
There may be an increased female predilection and they tend to peak around the 5th to 7th decades of life at the time o...
Article
Diffuse pulmonary nodules
Diffuse pulmonary nodules are usually seen as multiple pulmonary nodular opacifications on a HRCT chest scan. They can signify disease processes affecting either the interstitium or the airspace. They can range from a few millimeters to up to 1 cm and when very small and numerous there can be so...
Article
Diffuse pulmonary nodules (differential diagnosis)
A number of differentials must be kept in mind while approaching diffuse or multiple pulmonary nodules. Interpretation is easier if nodules are the only abnormality.
Differential diagnosis
These differentials can be narrowed down based on several criteria:
Based on appearance
miliary nodule...
Article
Diffuse pulmonary parenchymal amyloidosis
Diffuse pulmonary parenchymal amyloidosis is considered the least common form of pulmonary amyloidosis 6.
Clinical presentation
Unlike the nodular form, patients tend to be more symptomatic and often have symptoms of cough and shortness of breath. The most common presentation in this form ten...
Article
Diffuse tracheal narrowing
Conditions associated with diffuse tracheal narrowing or collapse include (in alphabetical order):
amyloidosis
chronic obstructive pulmonary disease (COPD): saber sheath trachea
granulomatosis with polyangiitis
tracheobronchial tuberculosis 3
tracheomalacia/tracheobronchomalacia (due to col...
Article
Diffusing capacity of the lungs for carbon monoxide
Diffusing capacity of the lungs for carbon monoxide (often abbreviated as DLCO) is a measure that determines how much oxygen travels from the alveoli of the lungs to the bloodstream. It is an index of the surface area available for gas exchange.
It becomes decreased in situations such as
emphy...
Article
Ditzel
A ditzel is an informal term widely used by radiologists to refer to indeterminate small pulmonary nodules 1.
History and etymology
The etymology of the term ditzel is disputed. It might be derived from the American term 'ditzy' meaning silly or inane, but there is a lack of good evidence for...
Article
Diverticulum
Diverticula are outpouchings of a hollow viscus and can be either true or false.
Occasionally a diverticulum is used in a more general sense to mean the outpouching of other anatomical structures, e.g. frontal intersinus septal cells are hypothesized to form as diverticula from the frontal sinu...
Article
Doege-Potter syndrome
Doege-Potter syndrome is a non-islet cell tumor hypoglycemia, secondary to a solitary fibrous tumor (SFT). It is rare, and more associated with malignant SFTs.
Article
Domestically acquired particulate lung disease
Domestically acquired particulate lung disease (DAPLD) or hut lung is a pneumoconiosis due to exposure from smoke from biomass fuel used in cooking in an enclosed space.
Epidemiology
Typically women who present with symptoms of a pneumoconiosis without the history of occupational exposure 2,3...
Article
Dot in box appearance
A "dot in box" appearance is a pattern that has been described with pulmonary lymphangitis carcinomatosis. The interlobular septal thickening from lymphangitis forms polygonal arcades accounting for the box while the prominence of the centrilobular bronchovascular bundle is thought to represent...
Article
Double aortic arch
Double aortic arches are the most common symptomatic type of the aortic arch variant. It may account for up to 50-60% of vascular rings.
Clinical presentation
Double aortic arch is mostly diagnosed in childhood due to symptoms related to esophageal and/or tracheal obstruction. Respiratory symp...
Article
Double artery sign
The double artery sign refers to the appearance of a non-dilated mucus-filled bronchus adjacent to a pulmonary artery producing the appearance of a "double artery" on CT chest. This sign is considered a feature of a central endobronchial lesion such as a mucus plug or neoplasm.
Article
Double density sign (disambiguation)
The double density sign can refer to several radiological signs:
double density sign (left atrial enlargement)
double density sign (berry aneurysm)
double density sign (osteoid osteoma)
Article
Double diaphragm sign
The double diaphragm sign is one of several radiological signs seen with a pneumothorax in a supine patient.
Supine films are commonly performed in unwell patients, particularly in the ICU. In a supine patient with a pneumothorax, air may outline the anterior portions of the hemidiaphragm and c...
Article
Double lumen cannula for VV ECMO
The double lumen cannula enables veno-venous extracorporeal membrane oxygenation (VV ECMO) to patients with severe respiratory failure. It is often used as a bridge to lung transplant.
The cannulation is usually performed via the right jugular vein. This position allows the patients to stay aw...
Article
Double lumen endotracheal tube
A double lumen endotracheal tube is a type of intubation device where there are two lumens.
Indications
It is designed to isolate the lungs from one another anatomically and/or physiologically:
anatomical lung separation: isolation of diseased lung from contaminating the non-diseased lung
ma...
Article
Double lung point sign (Ultrasound)
The double lung point sign refers to a sharp boundary found between relatively aerated superior lung fields and coalescent "B‐lines" (representing interstitial edema) in the basal lung fields, with a reported sensitivity of 45.6%-76.7% and a specificity of 94.8%-100% 1,3 in diagnosing transient ...
Article
Doughnut sign (chest)
The doughnut sign can be appreciated on the lateral chest radiograph of patients with mediastinal adenopathy, most commonly seen in pediatric patients with pulmonary tuberculosis infection1.
The sign is made up of precarinal, subcarinal and retrocarinal lymph nodes which surround the radiolucen...
Article
Doughnut sign (disambiguation)
The doughnut sign can refer to a variety of different signs:
doughnut sign (bone scan)
doughnut sign (bowel)
crescent in a doughnut sign (bowel)
doughnut sign (chest)
doughnut sign (orbit)
Article
Drowning (postmortem findings)
Drowning is one of the most prevalent causes of non-natural death. According to the World Health Organization (WHO), an estimated 360,000 annual deaths occur due to drowning.
This article concerns itself with postmortem appearances in fatalities from drowning. For non-fatal pulmonary changes pl...
Article
Drug and toxin induced pulmonary hypertension
Drug and toxin induced pulmonary hypertension is one of the causes of pulmonary arterial hypertension. It falls under group 1.3 under the Dana point classification system of pulmonary hypertension.
Pathology
A wide range of difference drugs have been associated with developing pulmonary hyper...
Article
Drug-induced lung disease
Drug-induced lung disease can result from a number of agents and may have a myriad of presentations, ranging from an adult respiratory distress syndrome type picture to established pulmonary fibrosis.
Due to this, it can be extremely difficult to pinpoint the offending agent on imaging appearan...
Article
Drug rash with eosinophilia and systemic symptoms syndrome
The drug rash with eosinophilia and systemic symptoms (DRESS) syndrome typically manifests as a skin rash, fever, lymph nodal enlargement with variable internal organ involvement, and represents a hypersensitivity reaction to medication.
Clinical presentation
Clinical presentation can be vari...
Article
Ductus arteriosus
The ductus arteriosum (DA) (or arteriosus) is the thick short conduit for blood to bypass the non-ventilated lungs in the fetus. It is located between and connects the proximal left pulmonary artery and the undersurface of the aortic arch distal to the origin of the last branch of the arch, at t...
Article
Ductus diverticulum
Aortic ductus diverticulum is a developmental outpouching of the thoracic aorta which may be mistaken for an acute aortic injury.
Gross anatomy
It is usually seen at the anteromedial aspect of the aorta at site of the aortic isthmus, where the ligamentum arteriosum attaches. It is also the sit...
Article
Dynamic tracheal collapse
Dynamic tracheal collapse refers to collapse of the trachea during expiration. It is perhaps best assessed on CT in the end expiratory phase. An inspiratory series is also useful for comparative purposes. The term excessive dynamic airway collapse (EDAC) refers to abnormal and exaggerated bulgin...
Article
Dysphagia
Dysphagia refers to subjective awareness of difficulty or obstruction during swallowing. It is a relatively common and increasingly prevalent clinical problem. Odynophagia is the term for painful swallowing.
Fluoroscopy is the mainstay of imaging assessment but manometry can help evaluate the e...
Article
Dysphagia lusoria
Dysphagia lusoria is an impairment of swallowing due to compression from an aberrant right subclavian artery (arteria lusoria).
Clinical presentation
Most patients with aberrant right subclavian arteries do not have symptoms. Some present with mild dysphagia, while a small minority have a seve...
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...
Article
Ectopic meningioma
An ectopic meningioma (or primary ectopic meningioma) refers to rare situations where a meningioma arises outside the dura.
These can occur at various sites but usually occur in the head and neck region.
Reported sites include
scalp skin
ear and temporal bone
sinonasal tract
mandible 1
or...
Article
EGFR mutation
Epidermal growth factor receptor (EGFR) mutation can be expressed in a large proportion of non-small cell lung carcinomas (NSCLC). However, certain subtypes such as invasive mucinous adenocarcinoma of the lung can have very low expression.
The presence of this mutation can be assessed on biopsy...
Article
Egg and banana sign (pulmonary hypertension)
The egg and banana sign is a sign for the diagnosis of pulmonary arterial hypertension (PAH) on axial CT/MR images. It refers to the appearance of the aortic arch (banana) next to a distorted main pulmonary artery (egg). Like an egg, the main pulmonary artery is preferentially dilated in the PA ...
Article
Eggshell calcification in thorax and mediastinum (mnemonic)
Helpful mnemonics to remember the major causes of eggshell calcification of the nodes in the thorax and mediastinum are:
A Silly Cool Sergeant Likes His Tubercular Blast
Sally Smith Likes Her Smart ABC Mnemonic
Mnemonics
A Silly Cool Sergeant Likes His Tubercular Blast
A: amyloidosis
S: s...
Article
Eggshell calcification (lymph nodes)
Eggshell calcification refers to fine calcification seen at the periphery of a mass and usually relates to lamellar lymph node calcification. For similar appearance in the breast see eggshell calcification (breast).
In 1967 Jacobsen and Felson published criteria to help "avoid over-reading of t...
Article
Ehlers-Danlos syndrome
Ehlers-Danlos syndrome comprises a heterogeneous group of collagen disorders (hereditary connective tissue disease).
Epidemiology
There is a recognized male predominance.
Clinical presentation
Ehlers-Danlos syndrome clinically manifests with
skin hyperelasticity and fragility
joint hypermo...
Article
Eisenmenger syndrome
The 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 high pressure and high flow 3. As su...
Article
Elastofibroma dorsi
Elastofibroma dorsi is a benign soft-tissue tumor 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 is around 65-70 years.
Clinical presentation
Ela...
Article
Elephant trunk repair
An elephant trunk repair is a type of open repair procedure devised to address combined aneurysms, it is often a two staged procedure wherein the arch repair is facilitated by sternotomy and a second staged procedure is performed via left thoracotomy for the descending or thoracoabdominal aorta...
Article
Elevated diaphragm
Elevated diaphragm refers to the symmetrical elevation of both domes of the diaphragm.
Pathology
Etiology
There is some overlap with causes of an elevated hemidiaphragm.
Technical
supine position
poor inspiratory effort
Patient factors
obesity
pregnancy
Diaphragmatic pathology
paral...
Article
Elevated hemidiaphragm
An elevated hemidiaphragm may result from direct and indirect causes which include:
above the diaphragm 1
decreased lung volume
atelectasis/collapse
prior lobectomy or pneumonectomy
pulmonary hypoplasia
diaphragm 3-7
phrenic nerve palsy
diaphragmatic eventration
contralateral stroke: ...
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...
Article
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...
Article
Emphysema (disambiguation)
Emphysema refers to any disease process involving an abnormal accumulation of air/gas in the tissues. When used alone, it is usually taken to mean the lung disease, pulmonary emphysema, which forms part of the spectrum of chronic obstructive pulmonary disease (COPD).
gastric emphysema: include...
Article
Empty cyst sign
The empty cyst sign is described in hydatid disease. After rupture of the cyst and complete evacuation of its content, the pericyst becomes empty as an air-filled cyst on x-ray or CT 1,2. With superadded infection, an air-fluid level may appear within the cyst, mimicking a lung abscess 2.
Article
Empyema
Empyemas are purulent inflammatory collections within a body cavity. Contrast this with abscesses, which arise within parenchymal tissue, rather than occupying a pre-existing anatomical space.
Terminology
Colloquially, the standalone term empyema is used to refer to thoracic empyemas but there...
Article
Empyema necessitans
Empyema necessitans (also sometimes spelled as empyema necessitasis) refers to extension of an empyema out of the pleural space and into the neighboring chest wall and surrounding soft tissues.
Pathology
It may either occur due the virulence of the organism or may be facilitated by previous th...
Article
Empyema vs pleural effusion
An empyema can resemble a pleural effusion and can mimic a peripheral pulmonary abscess. Features that help distinguish a pleural effusion from an empyema include:
Shape and location
Empyemas usually:
form an obtuse angle with the chest wall
unilateral or markedly asymmetric whereas pleural ...
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 hemangioma
An endobronchial hemangioma is a rare benign lesion which can occur in the tracheobronchial tree.
Clinical presentation
Patients may present with hemoptysis and cough.
Radiographic features
Maybe be occult on chest radiographs. On CT usually seen as circumscribed lesions protruding into the ...
Article
Endobronchial intubation
Endobronchial intubation is the not infrequent finding of the endotracheal tube located in a bronchus 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 int...
Article
Endobronchial lipoma
Endobronchial lipomas are rare benign lesions arising from the adipose tissue in the submucosal layer of the bronchial wall.
Epidemiology
Rare benign tumor with a possible male predilection.
Clinical presentation
Presenting symptoms include a cough, sputum, hemoptysis and dyspnea; however, ...
Article
Endobronchial lipomatous hamartoma
Endobronchial lipomatous hamartoma is a type of hamartoma, found in the conducting airways, that can be considered as a variant of endobronchial hamartoma, with a predominant lipomatous component. In general endobronchial hamartomas are thought to contain more fat than parenchymal pulmonary ham...
Article
Endobronchial metastases
Endobronchial metastases are an uncommon form of intrathoracic metastases. They are much less common than intrapulmonary metastases.
Clinical presentation
The clinical presentation varies and includes:
hemoptysis
cough
post-obstructive pneumonitis from distal obstruction
Pathology
Frequen...
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
K: Kaposi sarcoma
M: melanoma
R: renal cell carcinoma
B: breast cancer
C: colorectal carcinoma, cervical carcinoma, carcinoid
See also
endobronchi...
Article
Endobronchial valve
Endobronchial valves are one-way valves that restrict airflow to a particular lung segment. The devices are inserted via bronchoscopy. They permit the drainage of airway secretions during the expiratory phase but restrict incoming airflow during inspiration 1.
They were originally designed as a...
Article
Endogenous lipoid pneumonia
Endogenous lipoid pneumonia, also known as idiopathic lipoid pneumonia, is one of the two types of lipoid pneumonias. It is also known as “cholesterol pneumonia” or “golden pneumonia”
Please refer to the main article for a broad discussion, including clinical presentation, radiographic features...
Article
Enlargement of the cardiac silhouette
Enlargement of the cardiac silhouette on a frontal (or PA) 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
AP projection (e.g supine radiographs taken w...
Article
Eosinophilic granulomatosis with polyangiitis
Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as the Churg-Strauss syndrome (CSS), refers to a small to medium vessel necrotizing pulmonary vasculitis. It is also classified under the spectrum of eosinophilic lung disease and as a type of pulmonary angiitis and granuloma...
Article
Eosinophilic lung disease
Eosinophilic lung diseases are a heterogenous group of disorders that are characterized by excess infiltration of 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
Eparterial bronchus
The eparterial bronchus is a synonymous term for the right superior lobar bronchus. Its name is derived from the bronchus being the only one originating superior to the level of the pulmonary artery. Conversely, all other bronchi can be referred to by their anatomical relationship to the pulmona...
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 bor...
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
Erdheim-Chester disease (ECD) is a rare non-Langerhans cell, non-familial multisystemic histiocytosis, 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 middl...
Article
Erdheim-Chester disease (pulmonary manifestations)
Pulmonary manifestations of Erdheim-Chester disease are uncommon.
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 interlobular septal thickening and fiss...
Article
Erect chest x-ray (summary)
This is a basic article for medical students and other non-radiologists
Erect chest x-rays are standard positioning but are also a specific examination performed for the assessment of subdiaphragmatic free gas (pneumoperitoneum).
Reference article
This is a summary article; we do not have a m...
Article
Esophageal and esophagogastric junction adenocarcinoma (staging)
Esophageal and esophagogastric junction adenocarcinoma staging refers to TNM staging of adenocarcinoma originating in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the gastric cardia).
Related histologies included in this system are high...
Article
Esophageal and esophagogastric junction squamous cell carcinoma (staging)
Esophageal and esophagogastric junction squamous cell carcinoma staging refers to TNM staging of squamous cell carcinoma originating in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the gastric cardia).
Related histologies included in th...
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 (chest wall)
Ewing sarcoma family of tumors (ESFT), also referred as Ewing sarcomas of the chest wall, are malignant tumors affecting children and young adults, originating either from the osseous structures or the soft tissues of the chest wall.
On imaging, they are usually characterized as a large extrap...
Article
Excessive dynamic airway collapse
Excessive dynamic airway collapse (EDAC) refers to a dynamic form of central airway obstruction characterized by a decrease of ≥50% (more recent publications suggest >70%) in the cross-sectional area of the tracheobronchial lumen. Diagnosis is usually confirmed by dynamic cross-sectional imaging...
Article
Excipient lung disease
Excipient lung disease (ELD) refers to a granulomatous angiocentric pulmonary response to the intravenous injection of fillers in crushed oral tablets or particulate agents in illicit street drugs.
Terminology
Excipients are insoluble inert fillers used to protect the active components of drug...
Article
Exogenous lipoid pneumonia
Exogenous lipoid pneumonia is a form of lipoid pneumonia. Please refer to the main article for a broader discussion.
In terms of the onset of the presentation, it can be divided into two different forms:
acute exogenous lipoid pneumonia
uncommon and typically is caused by an episode of aspir...
Article
External intercostal muscle
The external (or outermost) intercostal muscles are important muscles 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 o...
Article
Extracorporeal membrane oxygenation
Extracorporeal membrane oxygenation (ECMO) is used as a modified pulmonary or cardiopulmonary bypass technique in those with severe cardiac and/or respiratory failure refractory to conventional ventilatory support and medical intervention 1,3. There are two access paths for extracorporeal life s...
Article
Extramedullary hematopoiesis
Extramedullary hematopoiesis is a response to the failure of erythropoiesis in the bone marrow.
This article aims to a general approach on the condition, for a dedicated discussion for a particularly involved organ, please refer to the specific articles on:
extramedullary hematopoiesis in the...
Article
Extrapleural air sign (pneumomediastinum)
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 of gas between the parietal pleura and the diaphragm. On a lateral projection, the gas forms a radiolucent pocket of gas posterior to the d...
Article
Extrapleural fat
Extrapleural fat is a benign condition and refers to relative 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...
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 extrapleural fat by an extrapleural fluid collection, extrapleural hematoma or extrapleural mass. The presence of the extrapleural fat sign is indicative...
Article
Extrapleural hematoma
Extrapleural hematomas are uncommon and usually seen in the context of rib fracture, subclavian venous catheter traumatic insertion, and blunt chest injury.
Pathology
Extrapleural hematomas result from the accumulation of blood in the extrapleural space where the overlying extrapleural fat is ...
Article
Extrapleural sign
The extrapleural sign, described by Ben 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 pleural or extrapleural in natu...
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...
Article
F-18 fluorodeoxyglucose (FDG) embolism
F-18 fluorodeoxyglucose (FDG) embolism is a condition which results in a uniform intense FDG-avid pulmonary focus without any underlying structural CT correlate with an unremarkable follow-up PET-CT scan 1. It is thought to occur as a result of clumping of FDG with blood when the blood is withdr...