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.
1,786 results found
Article
AAST injury scoring scales
The American Association for the Surgery of Trauma (AAST) injury scoring scales are the most widely accepted and used system of classifying and categorizing traumatic injuries. Injury grade reflects severity, guides management, and aids in prognosis. Currently (early 2019), 32 different injury s...
Article
Aberrant left pulmonary artery
Aberrant left pulmonary artery, also known as pulmonary sling, represents an anatomical variant characterized by the left pulmonary artery arising from the right pulmonary artery and passing above the right main bronchus and in between the trachea and esophagus to reach the left lung. It may lea...
Article
Aberrant right subclavian artery
Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are one of the commonest of the aortic arch anomalies.
Epidemiology
The estimated incidence is 0.5-2%.
Clinical presentation
They are often asymptomatic, but around 10% of people may complain of tracheo-esophageal sym...
Article
Abscess
Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1:
a central core consisting of necrotic inflammatory cells and local tissue
peripheral halo of viable neutrophils
surrounded by a 'capsule' with dilated blood vessel...
Article
Absent pulmonary valve syndrome
Absent pulmonary valve syndrome (APVS) also known as congenital absence of pulmonary valve or pulmonary valve agenesis is a rare cardiac outflow tract anomaly.
Pathology
It is characterized by completely absent or rudimentary pulmonary valve. It can be associated with aneurysmal dilatation of...
Article
Accessory fissures of the lung
Accessory fissures of the lung usually occur at the borders of bronchopulmonary segments. They are common normal variants but are less commonly seen on imaging.
Some of the more common accessory fissure include 1:
azygos fissure: most commonly seen accessory fissure
inferior accessory fissur...
Article
Accessory hemiazygos vein
The accessory (or superior) hemiazygos vein forms part of the azygos system and along with the hemiazygos vein, it is partially analogous to the right-sided azygos vein. It drains the left superior hemithorax.
Terminology
Spelling it "hemiazygous" when referring to the vein is incorrect, rega...
Article
Accessory phrenic nerve
The accessory phrenic nerve is an anatomical variant seen in a little over one third of patients (36%). It most commonly arises from the ansa cervicalis, or slightly less commonly, the subclavian nerve. It is unknown as to how much the accessory phrenic nerve contributes to diaphragmatic functio...
Article
Achalasia
Achalasia (primary achalasia) is a failure of organized esophageal peristalsis causing impaired relaxation of the lower esophageal sphincter, and resulting in food stasis and often marked dilatation of the esophagus.
Obstruction of the distal esophagus from other non-functional etiologies, not...
Article
Acinar-predominant adenocarcinoma of the lung
Acinar-predominant adenocarcinoma of the lung is a histological subtype of non-mucinous invasive adenocarcinoma of the lung.
Terminology
In 2011, the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) 4 introd...
Article
Acinic cell carcinoma (lung)
Acinic cell carcinoma of the lung (also known as a Fechner tumor) is a type of lung carcinoma of the salivary gland type. It is extremely rare, especially when it presents in the form of primary acinic cell carcinoma.
Pathology
Histologically, they are comprised of clear cells with abundant gr...
Article
Acquired aortic conditions
There are many acquired aortic conditions. These include
aortic dissection
aortic rupture / transection
ascending aortic aneurysm
aortitis
thoracic aortic injury
abdominal aortic aneurysm
inflammatory abdominal aortic aneurysm
Article
Acute airspace opacification with lymphadenopathy (differential)
Acute airspace opacification with lymphadenopathy is a subset of the differential diagnosis for generalized airspace opacification and includes:
post-obstructive causes (usually chronic, but 'new' changes can occur)
primary lung cancer
pulmonary metastases
lymphoma/leukemia
infection
prim...
Article
Acute aspiration pneumonitis
Acute aspiration pneumonitis occurs when solid or liquid ingested particles get into the airways and lungs leading to inflammation.
This article will focus on the acute form of aspiration (c.f. chronic aspiration pneumonia), mainly in regards to its radiographic features, for a broader discuss...
Article
Acute bilateral airspace opacification (differential)
Acute bilateral airspace opacification is a subset of the larger differential diagnosis for airspace opacification. An exhaustive list of all possible causes of acute bilateral airspace opacities is long, but a useful way to consider the huge list is via the material within the airways:
infecti...
Article
Acute bronchitis
Acute bronchitis (plural: bronchitides) refers to acute-onset, short-term bronchial inflammation. It is usually self-limiting and often the result of a viral infection. Chest radiography is rarely necessary.
Epidemiology
Acute bronchitis can affect people of all ages, but it is commonest in ch...
Article
Acute coronary syndrome
Acute coronary syndrome (ACS) is a group of cardiac diagnoses along a spectrum of severity due to the interruption of coronary blood flow to the myocardium, which in decreasing severity are:
ST elevation myocardial infarction (STEMI)
non-ST elevation myocardial infarction (NSTEMI)
unstable an...
Article
Acute eosinophilic pneumonia
Acute eosinophilic pneumonia is a type of eosinophilic lung disease diagnosed when the following combination of clinical and radiographic findings occur 5,7:
febrile illness of less than five days' duration
hypoxemia
diffuse alveolar or mixed alveolar-interstitial opacities on chest radiograp...
Article
Acute exacerbation of interstitial lung disease
Acute exacerbation of interstitial lung disease (AE-ILD), which sometimes also encompasses acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF), is an acute, clinically significant deterioration which develops within less than 1 month without an obvious clinical precipitant such as fluid...
Article
Acute hypersensitivity pneumonitis
Acute hypersensitivity pneumonitis, also known as acute extrinsic allergic alveolitis, refers to the episodic form of this condition usually happening in just a few hours after the antigen exposure and often recurring with the re-exposure. It represents the most inflammatory side of the spectrum...
Article
Acute interstitial pneumonitis
Acute interstitial pneumonitis (AIP), also known as Hamman-Rich syndrome, is a rapidly progressive non-infectious interstitial lung disease of unknown etiology. It is considered the only acute process among the idiopathic interstitial pneumonias.
Terminology
AIP has a similar clinical present...
Article
Acute lung transplant rejection
Acute lung transplant rejection is one of the early post lung transplant complications.
Epidemiology
It can occur as several episodes and the first episode may occur early as 5 days after transplantation. The incidence is thought to peak at approximately 2 months post-transplantation (with sev...
Article
Acute lupus pneumonitis
Acute lupus pneumonitis is one of the presentations of thoracic manifestations of systemic lupus erythematosus.
Clinical presentation
Acute lupus pneumonitis presents with acute onset of fever, cough, tachypnea, and hypoxia.
Radiographic features
Plain radiograph
Appearances are non-specif...
Article
Acute pulmonary schistosomiasis
Acute pulmonary schistosomiasis refers to the acute form of pulmonary schistosomiasis.
Pathology
The acute form usually occurs at around 6 weeks after the infection and is thought to represent an allergic manifestation to the presence of Schistosoma worm or eggs.
Radiographic features
Plain ...
Article
Acute respiratory distress syndrome
Acute respiratory distress syndrome (ARDS) is a form of acute lung injury and occurs as a result of a severe pulmonary injury that causes alveolar damage heterogeneously throughout the lung. It can either result from a direct pulmonary source or as a response to systemic injury.
Terminology
A...
Article
Acute right heart syndrome
Acute right heart syndrome (ARHS) is defined as a sudden deterioration in right ventricular (RV) function and failure of the RV to deliver adequate blood flow to the pulmonary circulation. This can result in systemic hypoperfusion.
Pathology
ARHS can occur in several settings 1
in the setting...
Article
Acute unilateral airspace opacification (differential)
Acute unilateral airspace opacification is a subset of the differential diagnosis for airspace opacification.
Differential diagnosis
The exhaustive list of all possible causes would be huge, but a useful framework includes:
pus, i.e. pulmonary infection
bacterial pneumonia
fungal pneumoni...
Article
Adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma of lung
Adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma of the lung are relatively new classification entities which replace the now-defunct term bronchoalveolar carcinoma (BAC).
In 2011 the International Association for the Study of Lung Cancer (IASLC) and several...
Article
Adenocarcinoma in situ of the lung
Adenocarcinomas in situ (AIS) of the lung refer to a relatively new entity for a pre-invasive lesion in the lung. This entity partly replaces the noninvasive end of the previous term bronchoalveolar carcinoma. Adenocarcinoma in situ is defined as a localized adenocarcinoma of <3 cm that exhibits...
Article
Adenocarcinoma of the lung
Adenocarcinoma of the lung is the most common histologic type of lung cancer. Grouped under the non-small cell carcinomas of the lung, it is a malignant tumor with glandular differentiation or mucin production expressing in different patterns and degrees of differentiation.
This article brings...
Article
Adenoid cystic carcinoma
Adenoid cystic carcinomas are a rare histological subtype of adenocarcinoma.
Pathology
Adenoid cystic carcinomas are generally considered low grade 4. The tumors have a notable tendency for perineural spread.
Location
They have a wide distribution and mainly occur in relation to the airways,...
Article
Adenoid cystic carcinoma of the lung
Adenoid cystic carcinoma (ACC) of the lung is a type of non-small cell lung cancer.
Pathology
They are classified under lung carcinomas of the salivary gland type. Primary occurrence in the lung parenchyma is rare, while in the thorax they occur more commonly as adenoid cystic carcinoma of the...
Article
Adenoid cystic carcinoma of the tracheobronchial tree
Adenoid cystic carcinomas of the tracheobronchial tree are a type of low-grade tracheal tumor. They are considered to be the second most common primary tumor of the trachea.
Epidemiology
They are usually first recognized in patients in their 4th and 5th decades. There is no recognized gender p...
Article
Adenosquamous carcinoma of lung
Adenosquamous carcinoma of the lung is a rare type of non-small cell lung cancer containing both components of lung adenocarcinoma and lung squamous cell carcinoma (SCC).
Epidemiology
It is thought to constituting 0.4-4% of cases non-small cell lung cancer.
Risk factors
cigarette smoking 8
...
Article
Adhesive atelectasis
Adhesive atelectasis refers to the specific form of lung atelectasis that occurs due to the decrease or absence of pulmonary surfactant produced by type II pneumocytes. Without sufficient surfactant the alveoli collapse due to increased surface tension. It is most commonly seen in neonates with ...
Article
Adrenal tuberculosis
Tuberculous adrenalitis is the result of adrenal mycobacterium tuberculosis (TB) infection. Its incidence has decreased in the western world with the declining incidence of tuberculosis.
Pathology
As the tuberculous infection causes destruction of the adrenal cortex, primary adrenal insufficie...
Article
Adult chest radiograph common exam pathology
Adult chest radiograph common exam pathology is essential to consider in the build up to radiology exams. The list of potential diagnoses is apparently endless, but there are some favorites that seem to appear with more frequency.
When dealing with the adult chest radiograph in the exam setting...
Article
Adult chest radiograph in the exam setting
A chest radiograph in the exam setting may contain a vast variety of pathology. However, consider the history and correlate the likely diagnoses that may be demonstrated on film. Furthermore, check your review areas to ensure that the abnormality isn't at the corner of the film.
Locating pathol...
Article
Adult chest radiograph pathology checklist
The adult chest radiograph pathology checklist is just a pathology checklist of things not to miss when reviewing a chest radiograph, especially in the exam setting.
standard review areas
apices
retrocardiac area
hilar regions
below the diaphragm
right descending pulmonary artery (like a l...
Article
Adult chest radiograph set-pieces
There are a number of adult chest radiograph set-pieces. These are based on common patterns of disease that are seen on chest radiographs. Make sure that you have relevant differentials for these appearances and a quick oral set-piece for them when they come up.
Pulmonary parenchyma
lobar coll...
Article
Aflatoxins
Aflatoxins are naturally-occurring mycotoxins that are produced by Aspergillus species, especially Aspergillus flavus. They are acutely toxic and carcinogenic.
Acute exposure
High-level aflatoxin exposure can result in acute aflatoxicosis with acute hepatic necrosis, leading to cirrhosis, and ...
Article
Agenesis (general)
The biological/medical term agenesis (plural: ageneses) refers to failure of an organ to grow or develop during the embryological period.
Examples include:
appendiceal agenesis
cerebellar agenesis
corpus callosum agenesis
dental agenesis (anodontia)
diaphragmatic agenesis
dorsal pancreati...
Article
Agenesis of the diaphragm
Agenesis of the diaphragm is a congenital diaphragmatic developmental anomaly where all or part of diaphragm fails to form. It can sometimes be thought of as an extreme form congenital diaphragmatic herniation 1.
Pathology
The agenesis can either be unilateral or bilateral. Herniation of abdom...
Article
AIDS-defining illness
AIDS-defining illnesses are conditions that in the setting of a HIV infection confirm the diagnosis of AIDS and do not commonly occur in immunocompetent individuals 2. According to the CDC surveillance case definition 1, they are:
Infectious
bacterial infections: multiple or recurrent
candidi...
Article
AIDS-related pulmonary lymphoma
AIDS-related pulmonary lymphoma (ARPL) is classified as a distinct form of pulmonary lymphoma. Pulmonary involvement is a common extranodal site in AIDS-related NHL.
Pathology
ARPL is typically a high-grade B-cell non-Hodgkin's lymphoma and the majority of patients have advanced HIV infection,...
Article
Air bronchogram
Air bronchogram refers to the phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white). It is almost always caused by a pathologic airspace/alveolar process, in which something other than air fills the alveoli. Air bronchograms will not ...
Article
Air-bronchogram (summary)
This is a basic article for medical students and other non-radiologists
Air-bronchograms are gas-filled bronchi surrounded by alveoli filled with fluid, pus or other material 1. It is a very useful sign because it is highly sensitive and specific for the presence of lung consolidation rather th...
Article
Air bubble sign (pulmonary hydatid)
The air bubble sign is seen in CT of complicated (ruptured or infected) pulmonary hydatid cyst and refers to small bubbles of gas within the periphery of pulmonary mass and is helpful, particularly in endemic areas, in suggesting the diagnosis over other masses (e.g. metastases or primary lung t...
Article
Air crescent sign (lung)
An air crescent sign describes the crescent of air that can be seen in invasive aspergillosis, semi-invasive aspergillosis, or other processes that cause pulmonary necrosis. It usually heralds recovery and is the result of increased granulocyte activity.
Terminology
It should not be confused w...
Article
Air space nodule
An air space nodule is a small (few millimeters to 1 cm), ill-defined, nodular opacity that is often centrilobular in location and is non-specific, seen in many conditions. Commonly it represents a focal area of consolidation or peribronchiolar inflammation, and can indicate endobronchial spread...
Article
Airspace nodules
Airspace nodules are irregularly marginated nodular opacities with air bronchograms that tend to measure 8 mm in diameter. They are quite separate from pulmonary nodules that range in size, are homogeneous and well-defined (being surrounded by normal lung).
Article
Air space opacification
Air space opacification is a descriptive term that refers to filling of the pulmonary tree with material that attenuates x-rays more than the surrounding lung parenchyma. It is one of the many patterns of lung opacification and is equivalent to the pathological diagnosis of pulmonary consolidati...
Article
Air-space opacification (summary)
This is a basic article for medical students and other non-radiologists
Air-space opacification is a descriptive term that refers to filling of the lung parenchyma with material that attenuates x-rays more than the unaffected surrounding lung tissue. It is the radiological correlate of the path...
Article
Air space opacities
The differential for air space opacities is extensive, and needs to be interpreted in context of chronicity (previous imaging) and clinical context. It is therefore useful to divide airspace opacities as follows:
acute airspace opacities with lymph node enlargement
acute airspace opacities: un...
Article
Air trapping
Air trapping in chest imaging refers to retention of excess gas (“air”) in all or part of the lung, especially during expiration, either as a result of complete or partial airway obstruction or as a result of local abnormalities in pulmonary compliance. It may also sometimes be observed in norma...
Article
Airway centered interstitial fibrosis
Airway centered interstitial fibrosis is a rare subtype of pulmonary fibrosis with variable outcomes.
Pathology
It is characterized by fibrosis of the respiratory bronchioles and the peribronchiolar interstitium. It may be triggered by exogenous agents or endogenous autoimmune conditions such ...
Article
Airway foreign bodies in children
Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common.
Epidemiology
Children under the age of four years are at increased risk of foreign body (FB) aspiration, with a slight male predominance 1.
Cl...
Article
Airway invasive aspergillosis
Airway invasive aspergillosis refers to a form of invasive aspergillosis that affects the airways as the major or only feature.
Epidemiology
It usually occurs in immunocompromised neutropenic patients, particularly AIDS patients. Aspergillosis affecting the airways as the major or only feature...
Article
Airway pressure release ventilation
Airway pressure release ventilation (APRV) is an alternative mode for mechanical ventilation. It can be adopted as a method of alternative method for difficult-to-oxygenate patients with acute lung injury / acute respiratory distress syndrome (ALI/ARDS).
Its is usually not recommended in patien...
Article
A-line (ultrasound)
An a-line is an ultrasonographic artifact appreciated during the insonation of an aerated lung. 1
The term may be applied to the horizontal, echogenic long path reverberation artifacts that occur beneath the pleural line at multiples of the distance between the ultrasound probe and the visceral...
Article
Allergic bronchopulmonary aspergillosis
Allergic bronchopulmonary aspergillosis (ABPA) is at the mild end of the spectrum of disease caused by pulmonary aspergillosis and can be classified as an eosinophilic lung disease 2-4.
Epidemiology
This entity is most commonly encountered in patients with longstanding asthma, and only occasio...
Article
All-trans retinoic acid syndrome
All-trans retinoic acid (ATRA) syndrome, more recently known as differentiation syndrome (DS) 8, is a condition that can occur with patients with acute promyelocytic leukemia who are on therapeutic all-trans-retinoic acid (ATRA).
All-trans-retinoic acid (ATRA) is a normal constituent of plasma ...
Article
Alpha-1-antitrypsin deficiency
Alpha-1-antitrypsin (A1AT) deficiency is a hereditary metabolic disorder and is the most common genetic cause of emphysema and metabolic liver disease in children. It results in the unopposed action of neutrophil elastase and subsequent severe basal panlobular emphysema and respiratory symptoms....
Article
Alveolar sarcoidosis
Alveolar sarcoidosis is an atypical pulmonary manifestation of sarcoidosis.
Epidemiology
This appearance may be apparent in approximately 4% of those with pulmonary sarcoidosis on plain film 1 and up to 15% on CT 2.
Pathology
This appearance is thought to result from the aggregation of a va...
Article
Alveoli
The alveoli (singular: alveolus) are tiny hollow air sacs that comprise the basic unit of respiration.
Gross Anatomy
Alveoli are found within the lung parenchyma and are found at the terminal ends of the respiratory tree, clustered around alveolar sacs and alveolar ducts. Each alveolus is app...
Article
Amiodarone lung
Amiodarone lung is an interstitial lung disease seen in patients being administered amiodarone and can manifest in a number of histopathologic patterns.
Epidemiology
The reported prevalence of pulmonary toxicity in patients receiving amiodarone is ~10% (range 2-18%) 8.
Patients are usually el...
Article
Amniotic fluid embolism to lung
Amniotic fluid embolism is a special type of pulmonary embolism where the embolus is comprised of amniotic fluid. It can be a highly fatal complication of pregnancy, with an 80% maternal mortality rate.
Epidemiology
It is thought to complicate 1/8,000-80,000 pregnancies.
Clinical presentatio...
Article
Anaphylaxis
Anaphylaxis (also known as anaphylactic shock or reaction) is an acute severe systemic type I hypersensitivity reaction, commonly presenting with urticaria/angioedema, hypotension and bronchial hyperreactivity. It may be fatal.
Terminology
Anaphylactoid reactions result from non-immune system ...
Article
Anaplastic lymphoma kinase (ALK) fusion oncogene positive non small cell lung cancer
Anaplastic lymphoma kinase (ALK) fusion oncogene positive non small cell lung cancer refers to a specific set of non small cell lung cancers that contain an inversion in chromosome 2. They are associated with specific clinical features, including never or light smoking history, younger age, and ...
Article
Anaplastic lymphoma kinase (ALK) gene rearrangements
Anaplastic lymphoma kinase (ALK) gene rearrangements are known to occur in association with several tumors. The genes codes for an enzyme called anaplastic lymphoma kinase (ALK) or ALK tyrosine kinase receptor / CD246 which is thought o play a role in the brain development and exerts its effects...
Article
Anatomy curriculum
The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists.
General anatomy
Neuroanatomy
Head and neck anatomy
Thoracic anatomy
Abdominal and pelvic anatomy
Spinal anat...
Article
Angioinvasive aspergillosis
Angioinvasive aspergillosis is the most severe and aggressive form of invasive aspergillosis. It is a life-threatening condition that requires prompt treatment. Fortunately, it is not seen in the general population and only occurs in profoundly immunocompromised patients.
Epidemiology
Angioin...
Article
Angiosarcoma involving the lung
Angiosarcoma involving the lung includes:
metastatic angiosarcoma to lung 1
commoner
usual primary sites include the heart and breast 2
primary pulmonary angiosarcoma: very rare
See also
angiosarcoma
Article
Ankylosing spondylitis (thoracic manifestations)
Thoracic manifestations of ankylosing spondylitis can be varied. For a general discussion of the condition refer to the parent article on ankylosing spondylitis.
It can affect the tracheobronchial tree and the lung parenchyma, and the disease spectrum includes:
upper lobe fibrocystic changes -...
Article
Anomalous systemic arterial supply to normal lung
Anomalous systemic arterial supply to normal lung is an anatomical variant in which a portion of the lung (usually a basal segment) is supplied by a systemic vessel without a distinct pulmonary sequestration.
Terminology
It was traditionally (perhaps inappropriately since not a true sequestrat...
Article
Anorexia nervosa
Anorexia nervosa is a psychiatric disorder characterized by distorted self-perception of body weight leading to starvation, obsession with remaining underweight, and an excessive fear of gaining weight. One in five patients with anorexia dies due to complications of the disease.
Epidemiology
T...
Article
Anterior bronchus sign
The anterior bronchus sign refers to the appearance of the anterior segmental bronchus of the upper lobes as seen on a frontal chest radiograph.
Gross anatomy
The anterior segment bronchus of the upper lobes courses anteriorly and laterally. When the orientation is predominantly anteriorly the...
Article
Anterior junction line
The anterior junction (or junctional) line is a feature of frontal chest radiographs and chest CTs. It is a result of the parietal and visceral pleura meeting anteromedially. It normally contains a small amount of fat but can form a stripe of variable thickness if there is a lot of fat present o...
Article
Anterior mediastinal germ cell tumors
Germ cell tumors are one of the causes of anterior mediastinal mass, and any of the germ cell histologies may be identified. They can therefore be divided histologically into:
seminoma
non-seminomatous germ cell tumors (NSGCT)
embryonal cell carcinoma
choriocarcinoma
yolk sac tumor
teratom...
Article
Anterior mediastinal mass in the exam
Getting a film with an anterior mediastinal mass in the exam is one of the many exam set-pieces that can be prepared for.
The film goes up and after a couple of seconds pause, you need to start talking:
CXR
There is a left sided mediastinal mass that makes obtuse angles with the mediastinal c...
Article
Anterior mediastinum
The anterior mediastinum is the portion of the mediastinum anterior to the pericardium and below the thoracic plane.
It forms the anterior part of the inferior mediastinum, and contains the thymus, lymph nodes, and may contain the portions of a retrosternal thyroid.
Related pathology
The comm...
Article
Anterosuperior mediastinal mass (mnemonic)
The common causes of an anterosuperior mediastinal mass can be remembered by using the mnemonic:
5 Ts
Mnemonic
T: thymus
T: thyroid
T: thoracic aorta
T: terrible lymphoma
T: teratoma and germ cell tumors - see mediastinal germ cell tumors
Testicular cancer metastasis can represent a sixt...
Article
Anthrax
Anthrax is a zoonosis caused by Bacillus Anthracis. There are four types of anthrax: inhalational anthrax (also known as woolsorter's disease and ragsorter's disease), cutaneous anthrax, injection anthrax and intestinal anthrax.
Epidemiology
The disease burden of anthrax decreased so dramatica...
Article
Anti jo 1 antibody positive interstitial lung disease
Anti jo 1 antibody positive interstitial lung disease refer to cases of interstitial lung disease occuring in the setting on anti Jo 1 antibody positivity.
Anti jo 1 antibody positivity has a recognized association with interstitial lung disease. This most commonly occurs in a setting of polymy...
Article
Anti melanoma differentiation associated gene 5 (MDA5) antibody positive clinically amyopathic dermatomyositis
Anti-MDA5 antibody-positive amyopathic dermatomyositis is a subtype of dermatomyositis where there is positivity to an anti-melanoma differentiation-associated gene 5 (MDA5) antibody. It has been reported to be associated with rapidly progressive interstitial lung disease (RP-ILD) resulting in h...
Article
Antineutrophil cytoplasmic antibody
Antineutrophil cytoplasmic antibodies (ANCAs) are a heterogenous class of IgG autoantibodies raised against the cellular contents of neutrophils, monocytes and endothelial cells 1. Under indirect immunofluorescence (IIF) microscopy, three ANCA staining patterns are observed, based on the varying...
Article
Anti-neutrophil cytoplasmic antibody associated vasculitides
Anti-neutrophil cytoplasmic antibody (ANCA) - associated vasculitides refer to a group of heterogeneous autoimmune diseases characterized by necrotizing vasculitides and positive ANCA titers. They are reactive to either proteinase-3 (PR3-ANCA) - cANCA or myeloperoxidase (MPO-ANCA) - pANCA. These...
Article
Antiphospholipid syndrome
Antiphospholipid syndrome is a systemic autoimmune disorder. It is usually defined as the clinical complex of vascular occlusion and ischemic events occurring in patients who have circulating antiphospholipid antibodies.
Clinical presentation
Antiphospholipid syndrome is characterized by venou...
Article
Antiphospholipid syndrome (pulmonary manifestations)
Pulmonary involvement in antiphospholipid syndrome is one of the most frequent arterial complications of antiphospholipid syndrome.
Pathology
It is essentially related to pulmonary arterial microthrombosis and may cause a wide spectrum of conditions, which include 3-5:
pulmonary thromboembol...
Article
Anti-synthetase syndrome
Anti-synthetase syndrome (ASS) is a systemic, inflammatory, autoimmune disease that is characterized by inflammatory myositis, polyarthritis associated with interstitial lung disease (ILD) and anti-synthetase autoantibodies.
Pathology
ASS can result from autoantibodies to eight of the aminoacy...
Article
Antler sign (lung)
The antler sign is an uncommon sign of lung torsion on CT where branches from the main pulmonary artery all arise from a single side, indicating twisting of the lobe or lung.
In the normal lung, the main pulmonary arteries are straight and lobar and segmental branches arise from it on both side...
Article
Aortic arch
The aortic arch represents the direct continuation of the ascending aorta and represents a key area for a review of normal variant anatomy and a wide range of pathological processes that range from congenital anomalies to traumatic injury.
Summary
origin: continuation of the ascending aorta at...
Article
Aortic dissection
Aortic dissection is the most common form of the acute aortic syndromes and a type of arterial dissection. It occurs when blood enters the medial layer of the aortic wall through a tear or penetrating ulcer in the intima and tracks along the media, forming a second blood-filled channel within th...