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.

Create new article

Filtered (1)Done (clear)

+Systems

+Article Sections

+Sort By

Support Radiopaedia and see fewer ads

1,540 results found

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. At the time of writing (mid 2016), 32 differe...

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...

Aberrant right subclavian artery

Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are the commonest of the aortic arch anomalies 2. Epidemiology The estimated incidence is 0.5-2%. Clinical presentation They are often asymptomatic, but around 10% of people may complain of tracheo-esophageal symptoms...

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...

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...

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. Gross anatomy Origin and course The accessory hemiazygos vein is formed by the con...

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...

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...

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...

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...

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

Acute airspace opacification with lymphadenopathy (differential)

Acute airspace opacification with lymphadenopathy is a subset of the differential diagnosis for generalised airspace opacification and includes: post-obstructive causes (usually chronic, but 'new' changes can occur) primary lung cancer pulmonary metastases lymphoma/leukemia infection prim...

Acute aspiration pneumonitis

Acute aspiration pneumonitis refers to a form aspiration pneumonia where the time of onset is rapid. Radiographic features Plain radiograph / CT Features can be variable and can range from a pulmonary edema pattern to areas of consolidation. These changes may have a gravity dependent distribu...

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...

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...

Acute eosinophilic pneumonia

Acute eosinophilic pneumonia (AEP) is a type of eosinophilic lung disease. It is diagnosed when the following combination 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...

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 a situation as an acute, clinically significant deterioration which develops within less than 1 month without an obvious clinical precipitant ...

Acute hypersensitivity pneumonitis

Acute hypersensitivity pneumonitis (AHP) refers to the acute form of hypersensitivity pneumonitis although this classification system has recently been challenged 4. For a general discussion of the condition, refer to the parent article. Clinical presentation Fever, chills, myalgia, headaches,...

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. Epidemiology Truly idiopathic AIP tends to occur...

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...

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...

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 ...

Acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a form of acute lung injury (ALI) 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. Pathology...

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...

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. infection bacterial pneumonia fungal pneumonia viral p...

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...

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 localised adenocarcinoma of <3 cm that exhibits...

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...

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,...

Adenoid cystic carcinoma of lung

Adenoid cystic carcinoma (ACC) of the lung is a type of non-small cell lung cancer. 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 tracheobron...

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 recognised in patients in their 4th and 5th decades. There is no recognised gender p...

Adenosquamous carcinoma of lung

Adenosquamous carcinoma (ASC) of the lung is a rare type of non-small cell lung cancer. Epidemiology It is thought to constituting 0.4-4% of cases non-small cell lung cancer. Pathology The definition of adenosquamous carcinoma indicates a carcinoma showing components of adenocarcinoma and sq...

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 favourites that seem to appear with more frequency. When dealing with the adult chest radiograph in the exam settin...

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...

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...

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 aural set-piece for them when they come up. Pulmonary parenchyma lobar col...

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 ...

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...

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 candid...

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,...

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 ...

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. It is a very useful sign because it is highly sensitive and specific for the presence of lung consolidation rather than...

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...

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. In angioinvasive fungal infection, the no...

Air space disease

Air space disease, or alveolar lung disease, is a process in which there is a filling of the lung's alveoli / acini. Radiographic features lobar or segmental distribution poorly marginated airspace nodules tendency to coalesce air bronchograms bat's wing (butterfly) distribution...

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...

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).

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...

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...

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...

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...

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...

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...

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...

A-line (ultrasound)

An a-line is an ultrasonographic artifact appreciated during 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-par...

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...

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. ...

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....

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...

Alveoli

The alveoli 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 approximately 0.2 mm in ...

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...

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 1/8000-80,000 pregnancies. Clinical presentation...

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 ...

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...

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...

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

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 -...

Anomalous systemic arterial supply to normal lung

Anomalous systemic arterial supply to normal lung is an anatomical variant where a portion of the lung (usually a basal segment) gets supplied by a systemic vessel without a distinct pulmonary sequestration. Terminology It was traditionally (perhaps inappropriately since not a true sequestrati...

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 ...

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. Normal anatomy The anterior segment bronchus of the upper lobes courses anteriorly and laterally. When the orientation is predominantly anteriorly th...

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...

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...

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...

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...

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...

Anti-neutrophil cytoplasmic antibody associated vasculitides

Anti-neutrophil cytoplasmic antibody-associated vasculitides refer to a group of heterogeneous autoimmune diseases characterized by necrotizing vasculitides and positive anti-neutrophil antibody titers. They are reactive to either proteinase-3 (PR3-ANCA) - cANCA or myeloperoxidase (MPO-ANCA) - p...

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...

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...

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...

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...

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...

Aortic dissection detection risk score

The aortic dissection detection risk score (ADD-RS) is a clinical decision tool that aids in grading the pretest probability of an acute aortic dissection. Scores range from 0-3, where 0 is classed as low risk, 1 is moderate risk and 2-3 is high risk 1. Criteria The three domains in which pati...

Aortic dissection detection risk score plus d-dimer

The use of the aortic dissection detection risk score plus d-dimer is a proposed standardized strategy of safely ruling out the diagnosis of an acute aortic syndrome. Similar to how the pulmonary embolism rule-out criteria (PERC) negates the need for further workup of a pulmonary embolism. Int...

Aortic hiatus

The aortic hiatus is one of the three major apertures through the diaphragm and lies at the level of T12. Strictly speaking, it is not a real aperture in the diaphragm, but an osseoaponeurotic opening between it and the vertebral column. The hiatus is situated slightly to the left of the midli...

Aortic intramural hematoma

Aortic intramural hematoma (IMH) is an atypical form of aortic dissection due to hemorrhage into the wall from the vasa vasorum without an intimal tear. It is part of the acute aortic syndrome spectrum. Epidemiology Typically aortic intramural hematomas are seen in older hypertensive patients....

Aortic knob

The aortic knob or knuckle refers to the frontal chest x-ray appearance of the distal aortic arch as it curves posterolaterally to continue as the descending thoracic aorta. It appears as a laterally-projecting bulge, as the medial aspect of the aorta cannot be seen separate from the mediastinum...

Aortic nipple

An aortic nipple is seen in about 10% of PA chest x-rays on the lateral surface of the aortic arch/aortic knob. It represents the left superior intercostal vein. When prominent, superior vena cava obstruction should be considered as the left superior intercostal vein serves as a collateral path...

Aortic pseudoaneurysm versus ductus diverticulum

Differentiation of aortic pseudoaneurysm from ductus diverticulum is critical, particularly in the trauma setting. A traumatic aortic pseudoaneurysm is a surgical emergency whereas a ductus diverticulum is a normal anatomy variant. The following are differentiating features: Aortic pseudoaneur...

Aortic-pulmonary stripe

The aortic-pulmonary stripe is an uncommon feature of frontal chest radiographs and was first described by Keats in 1972 1. It is formed by the interface of the pleural surface of the anterior segment of the left upper lobe contacting the mediastinal fat that is anterolateral to the pulmonary t...

Aortic transection

An aortic transection (also known as a traumatic aortic rupture) is a type of traumatic aortic injury. It is considered the second most common cause of death associated with motor vehicle accidents. Pathology It occurs from a near-complete tear through "all the layers" of the aorta due to tra...

Aortopulmonary septal defect

Aortopulmonary septal defect (APSD), also known as aortopulmonary window (APW), is a congenital anomaly where there is an abnormal communication between the proximal aorta and the pulmonary trunk in the presence of separate aortic and pulmonary valves. Terminology APSD should not be confused w...

Aortopulmonary window (radiograph)

The aortopulmonary (aortic-pulmonary or AP) window (also known as APW, but see 'Terminology' below) is a radiological mediastinal space seen on frontal chest radiographs. Terminology The term "aortopulmonary window" (also called an aortopulmonary septal defect) can also refer to a rare form of...

Apical lung disease (mnemonic)

A handy mnemonic to remember common apical lung diseases is: SET CARP or CARPETS Mnemonic S: sarcoidosis E: eosinophilic pneumonia T: tuberculosis C: cystic fibrosis A: ankylosing spondylitis R: radiation pneumonitis P: pneumoconiosis

Updating… Please wait.

Unable to process the form. Check for errors and try again.

Thank you for updating your details.