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.

14,938 results found
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Achondrogenesis 1B

Achondrogenesis type Ib, also known as Parenti-Fraccaro subtype, is a subtype of achondrogenesis and is an extremely rare skeletal dysplasia (chondrodysplasia).​​ Clinical presentation The fetuses frequently present in breech position. The physical appearance is strikingly abnormal and charact...
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Achondroplasia

Achondroplasia is a congenital genetic disorder resulting in rhizomelic dwarfism and is the most common skeletal dysplasia. It has numerous distinctive radiographic features.  Epidemiology It occurs due to sporadic mutations in the majority of cases but can be inherited as an autosomal dominan...
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Achondroplastic base of skull abnormalities

Achondroplasia is the most common cause of short-limb dwarfism. (For a general discussion, see the generic article on achondroplasia.) As the skull base forms by endochondral ossification whereas the skull vault by membranous ossification, there is a marked discrepancy in relative size as the s...
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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...
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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...
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Acinic cell carcinoma (salivary glands)

Acinic cell carcinomas of the salivary glands are rare malignant neoplasms that account for 1-3% of all salivary gland tumors.  Pathology Pathology may superficially resemble normal serous (acinar) cells of the salivary glands. It is considered a low-grade, indolent malignancy, but with a tend...
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Acoustic enhancement

Acoustic enhancement also called posterior enhancement or enhanced through transmission, refers to the increased echoes deep to structures that transmit sound exceptionally well. This is characteristic of fluid-filled structures such as cysts, the urinary bladder and the gallbladder. The fluid ...
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Acoustic impedance

Acoustic impedance (Z) is a physical property of tissue. It describes how much resistance an ultrasound beam encounters as it passes through a tissue. Acoustic impedance depends on: the density of the tissue (d, in kg/m3) the speed of the sound wave (c, in m/s) and they are related by: Z = ...
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Acoustic shadowing

The phenomenon of acoustic shadowing (sometimes, somewhat tautologically, called posterior acoustic shadowing) on an ultrasound image is characterized by a signal void behind structures that strongly absorb or reflect ultrasonic waves. It is a form of imaging artifact. This happens most frequent...
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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
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Acquired cholesteatoma

Acquired cholesteatomas makeup 98% of all middle ear cholesteatomas and are almost always closely related to the tympanic membrane, from which most are thought to arise.  Clinical presentation The vast majority of acquired cholesteatomas develop as a result of chronic middle ear infection and ...
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Acquired cystic kidney disease

Acquired cystic kidney disease (ACKD) is a condition that occurs in patients with end-stage renal disease (ESRD), especially when on dialysis treatment. They do not have a history of other cystic renal disease.  Epidemiology Its incidence increases with the amount of time a patient is azotemic...
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Acquired hepatocerebral degeneration

Acquired hepatocerebral degeneration is an uncommon irreversible extrapyramidal neurodegenerative condition encountered in patients with cirrhotic chronic liver disease, resulting in widespread cerebral, basal ganglia and cerebellar damage.  Terminology Acquired hepatocerebral degeneration is ...
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Acquired lipodystrophy

Acquired lipodystrophy is defined by the loss of body fat, insulin resistance and metabolic profile derangement. Subtypes include Barraquer-Simons syndrome, localized lipodystrophy and Lawrence syndrome. Lipodystrophy is illustrated as a complete or partial loss of adipose tissues from the body....
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Acquired tonsillar ectopia

Acquired tonsillar ectopia is usually thought of as a subgroup of cerebellar tonsillar ectopia in which downward displacement of the cerebellar tonsils is secondary to another well defined and distinct pathological process. This is to distinguish it from Chiari I malformations and low-lying tons...
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Acquired tracheo-esophageal fistula

An acquired tracheo-esophageal fistula refers to a pathological communication between the trachea and esophagus due to a secondary cause  Pathology Acquired causes of tracheo-esophageal fistulae can be divided into those that are related to malignancy (common) and those from other causes (unco...
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Acquisition time

The time of acquisition for a conventional spin echo or gradient echo sequence is the product of the repetition time, phase encoding steps, and number of averages (TR x phase steps x NEX). For example, with a one second TR, 128 phase steps, and two averages we would get an acquisition time of ab...
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Acral fibromyxoma

Acral fibromyxomas are benign mesenchymal proliferations prone to recurrence usually found in the subungual and periungual sites of the digits. Terminology Superficial acral fibromyxoma or digital fibromyxoma are other acceptable names, the term cellular digital fibroma is no longer recommende...
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Acrania

Acrania is a rare lethal congenital anomaly characterized by an absence of the calvaria. Epidemiology The estimated incidence is at ~1:1000 pregnancies 4.  Pathology  The condition is thought to result from abnormal migration of mesenchymal tissue, which normally covers the cerebral hemisphe...
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Acrania anencephaly sequence

Acrania anencephaly sequence is the progression from a relatively normal-appearing exposed brain due to an absent cranium (acrania) to an amorphous brain mass (exencephaly) to no recognisable brain tissue (anencephaly) 1. Epidemiology The acrania anencephaly sequence begins with acrania, which...
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Acrocephalopolysyndactyly

Acrocephalopolysyndactyly (ACPS) syndrome is comprised of a rare group of disorders collectively characterized by: calvarial anomalies: e.g. craniosynostoses digital anomalies: syndactyly and polydactyly While there can be some overlap in features, they can be primarily classified into the fo...
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Acrocephalosyndactyly

Acrocephalosyndactyly syndromes (ACS) are a rare group of disorders collectively characterized by: calvarial anomalies, e.g. craniosynostoses digital anomalies, e.g. syndactyly Classification While there can be some overlap in features, they can be primarily classified into the following maj...
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Acrodysostosis

Acrodysostosis is a rare skeletal dysplasia characterized by growth retardation, nasal hypoplasia, brachydactyly, midfacial deficiency, intellectual disability and deafness. Pathology Most cases are sporadic. Few cases with autosomal dominant transmission have been reported. It is believed to ...
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Acromegaly

Acromegaly is the result of excessive growth hormone production in skeletally mature patients, most commonly from a pituitary adenoma. The same excess of growth hormone in individuals whose epiphyses have not fused will result in gigantism (excessively tall stature).   Epidemiology Acromegaly ...
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Acromial apophysiolysis

Acromial apohysiolysis is a finding on shoulder MRI that may be encountered in patients with an unfused acromial apophysis. It is associated with athletes in throwing sports. Clinical presentation Presents with superior shoulder tenderness in a patient <25 years old, often in a young throwing ...
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Acromial types

The shape of the acromion had been initially divided into three types (which was known as the Bigliani classification) 3, to which a fourth has been added 2. They are used as a standardized way of describing the acromion, as well as predicting to a degree the incidence of impingement.  Classifi...
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Acromioclavicular injury

Acromioclavicular joint (AC) injuries are characterized by damage to the acromioclavicular joint and surrounding structures. Almost invariably traumatic in etiology, they range in severity from a mild sprain to complete disruption. Epidemiology AC joint injuries can occur at any age but most f...
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Acromioclavicular joint

The acromioclavicular joint (ACJ) is a planar diarthrodial synovial joint of the pectoral girdle. Gross anatomy The acromioclavicular joint is between the small facet of the convex distal clavicle and flat anteromedial acromion. The articular surfaces are lined with fibrocartilage (like the st...
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Acromioclavicular joint (AP view)

The acromioclavicular AP view is a single projection assessing the patency of the acromioclavicular joint. See also, acromioclavicular joint injuries. Indications The AP view of the acromioclavicular joint is often requested when the referrer either knows about or highly suspects an acromiocl...
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Acromioclavicular joint (AP weight-bearing view)

The acromioclavicular joint AP weight-bearing view, often performed together with the normal non-weight-bearing AP view, helps in ruling out joint displacement when it is suspected but not confirmed on the frontal image. Indications This view is used in the assessment of possible acromioclavic...
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Acromioclavicular joint configuration

There is much variation in acromioclavicular joint configuration, which may be confused with pathology. The relationship of the acromion to the distal clavicle at the AC joint can be described in the coronal plane as 1-3: horizontal: normal low-lying: associated with shoulder impingement (unfo...
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Acromioclavicular joint injection (technique)

Acromioclavicular joint (ACJ) injections under image guidance ensure precise delivery of an injectate into the joint.  Ultrasound allows for real time visualization of the needle and administration of the injectate. Fluoroscopy is an alternative method of image guidance. Indications pain - art...
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Acromioclavicular joint osteoarthritis

Acromioclavicular joint (ACJ) osteoarthritis (OA) is a common degenerative condition of the shoulder.  Epidemiology Acromioclavicular joint osteoarthritis accounts for ~20% (range 12.7-24%) of patients with shoulder pain. It most commonly presents in the fourth decade 3.  Pathology Acromiocl...
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Acromioclavicular joint series

The acromioclavicular (AC) joint radiographic series is used to evaluate the acromioclavicular joint and the distal clavicle. Indications AC radiographs are performed for a variety of indications including:  shoulder trauma direct blows to the shoulder region following a fall onto an adduct...
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Acromioclavicular joint (Zanca view)

The Zanca view is a specialized projection of the acromioclavicular joint (ACJ), which will better demonstrate the acromioclavicular joint free from superimposition and aid in the assessment of distal osteophytes. Indications The Zanca view is used in the assessment of acute and chronic acromi...
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Acromiohumeral interval

Acromiohumeral interval is a useful and reliable measurement on AP shoulder radiographs and when narrowed is indicative of rotator cuff tear or tendinopathy.  Measurement The shortest distance is measured.  Plain radiograph true AP shoulder radiograph measure from the cortical bone at the i...
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Acromion

The acromion (plural: acromia), also known as the acromial process, is a small projection of the scapula that extends anteriorly from the spine of the scapula.  Gross anatomy It forms the acromioclavicular joint (ACJ) with the lateral third of the clavicle and also connects with the coracoid p...
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Acromion fracture

The acromion process is the lateral projection of the scapula spine that extends anteriorly. Fractures of the scapula are uncommon injuries and account for ~3% of all shoulder fractures 1,2 while isolated acromion fractures occur rarely and account for only 9% of all scapular fractures 3. Patho...
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Acro-osteolysis

Acro-osteolysis (plural: acro-osteolyses) refers to resorption of the distal phalanx. The terminal tuft is most commonly affected. It is associated with a heterogeneous group of pathological entities and, some of which can be remembered by using the mnemonic PINCH FO. When there is linear bone ...
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Acro-osteolysis (mnemonic)

The causes of acro-osteolysis can be remembered using the mnemonic: PINCH FO Mnemonic P: psoriasis/pyknodysostosis I: injury, e.g. thermal burn, frost bite N: neuropathy, e.g. diabetes mellitus, leprosy C: collagen vascular disease, e.g. scleroderma, Raynaud disease H: hyperparathyroidism...
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Acroparesthesia

Acroparesthesia refers to tingling, pins-and-needles, burning or numbness or stiffness in the hands and feet, particularly the fingers and toes 1. Occasionally episodic pain is also present, which can be very severe 1.  It is one of the more common manifestations of Fabry disease (more common t...
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ACR Thyroid Imaging Reporting and Data System (ACR TI-RADS)

ACR TI-RADS is a reporting system for thyroid nodules on ultrasound proposed by the American College of Radiology (ACR) 1. This uses a standardized scoring system for reports providing users with recommendations for when to use fine needle aspiration (FNA) or ultrasound follow-up of suspicious ...
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Actinomycosis of the gallbladder

Actinomycosis of the gallbladder is rare and caused by Actinomyces spp. bacteria. It may present as biliary colic, cholecystitis or pancreatitis. It is a mimic of gallbladder carcinoma. Epidemiology Actinomycosis is endemic worldwide. It has no predilection for age, gender, ethnicity or climat...
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Activation function

In neural networks, activation functions perform a transformation on a weighted sum of inputs plus biases to a neuron in order to compute its output. Using a biological analogy, the activation function determines the “firing rate” of a neuron in response to an input or stimulus. These functions...
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Active surveillance

Active surveillance describes a management option aiming at close monitoring of a specific stage in disease and minimizing adverse treatment-related effects without compromising survival at the same time. Curative or definite treatment is intended and offered upon deterioration or upon explicit ...
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Acute abdominal pain

Acute abdominal pain is a common acute presentation in clinical practice. It encompasses a very broad range of possible etiologies and diagnoses, and imaging is routinely employed as the primary investigative tool in its modern management. Terminology A subgroup of patients with acute abdomina...
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Acute abdominal series

The acute abdominal series is a common set of abdominal radiographs obtained to evaluate bowel gas.  Indications The acute series is used for a variety of indications including:  determine the amount of bowel gas, with possible bowel distention assess air-fluid levels query pneumoperitoneum...
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Acute acalculous cholecystitis

Acute acalculous cholecystitis refers to the development of cholecystitis in gallbladder either without gallstones or with gallstones where they are not the contributory factor. It is thought to occur most often due to biliary stasis and/or gallbladder ischemia. Epidemiology Acute acalculous c...
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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...
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Acute aortic syndrome

Acute aortic syndrome describes the presentation of patients with one of a number of life-threatening aortic pathologies that give rise to aortic symptoms. The spectrum of these aortic emergencies include: aortic dissection aortic intramural hematoma penetrating atherosclerotic ulcer aortic...
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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...
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Acute bacterial meningitis complications (mnemonic)

The complications of acute bacterial meningitis can be remembered using the mnemonic: HACTIVE Mnemonic H: hydrocephalus A: abscess C: cerebritis / cranial nerve lesion T: thrombosis I: infarct V: ventriculitis/vasculopathy E: extra-axial collection: empyema and hygroma Related articles...
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Acute basilar artery occlusion

Acute occlusion of the basilar artery may cause brainstem or thalamic ischemia or infarction. It is a true neuro-interventional emergency and, if not treated early, brainstem infarction results in rapid deterioration in the level of consciousness and ultimately death. It is one of the posterior ...
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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...
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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...
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Acute calcific periarthritis

Acute calcific periarthritis is an acutely painful monoarticular condition characterized by the juxta-articular deposition of calcium hydroxyapatite crystals and local inflammation.  Epidemiology Affects both males and females over a wide age range, however, occurs more frequently in females t...
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Acute cerebellitis

Acute cerebellitis and acute cerebellar ataxia represent a spectrum of inflammatory processes characterized by sudden onset cerebellar dysfunction. It usually affects children and is related as a consequence of primary or secondary infection, or much less commonly as a result of a post-vaccinati...
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Acute cholangitis

Acute cholangitis, or ascending cholangitis, is a form of cholangitis and refers to the acute bacterial infection of the biliary tree. It is a condition with high mortality that necessitates emergent biliary decompression.  Clinical presentation The classical presentation is the Charcot triad ...
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Acute cholecystitis

Acute cholecystitis refers to the acute inflammation of the gallbladder. It is the primary complication of cholelithiasis and the most common cause of acute pain in the right upper quadrant (RUQ). Epidemiology Acute cholecystitis is a common cause of hospital admission and is responsible for a...
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Acute cholecystitis (summary)

This is a basic article for medical students and other non-radiologists Acute cholecystitis refers to the acute inflammation of the gallbladder. It is the primary complication of cholelithiasis and the most common cause of acute pain in the right upper quadrant (RUQ). Reference article This i...
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Acute compartment syndrome

Acute compartment syndrome is a limb and life-threatening surgical emergency. It is a painful condition caused by increased intracompartmental pressure, compromising perfusion and resulting in muscle and nerve damage within that compartment. Epidemiology Acute compartment syndrome is more comm...
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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...
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Acute disseminated encephalomyelitis (ADEM)

Acute disseminated encephalomyelitis (ADEM), as the name would suggest, is featured by a monophasic acute inflammation and demyelination of white matter typically following a recent (1-2 weeks prior) viral infection or vaccination 4,6. Grey matter, especially that of the basal ganglia, is also o...
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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...
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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...
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Acute fatty liver of pregnancy

Acute fatty liver of pregnancy (AFLP) is a rare pregnancy-associated condition that tends to manifest in the 3rd trimester of pregnancy or early postpartum period. Epidemiology The estimated incidence is at around 1:7000-20,000 births.  Clinical presentation Patients may present with nausea,...
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Acute gastritis

Acute gastritis is a broad term that encompasses a myriad of causes of gastric mucosal inflammation. Epidemiology  It depends on the etiology (see below). Clinical presentation asymptomatic epigastric pain/tenderness nausea and vomiting loss of appetite Pathology Etiology infection: H....
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Acute hemorrhagic leukoencephalitis

Acute hemorrhagic encephalomyelitis (AHEM), also known as acute hemorrhagic leukoencephalitis (AHLE), Hurst disease or Weston Hurst syndrome, is a very rare form of demyelinating disease. It occurs sporadically and may be considered as the most severe form of acute disseminated encephalomyelitis...
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Acute hepatitis

Acute hepatitis (plural: acute hepatitides) occurs when the liver suffers an injury with a resulting inflammatory reaction. The cause of the injury can happen in multiple different ways, and imaging findings are often non-specific. Acute hepatitis is a clinical diagnosis and a normal imaging app...
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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...
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Acute idiopathic scrotal edema

Acute idiopathic scrotal edema (AISE) is a self-limiting condition characterized by marked edema of the skin and dartos fascia without involvement of the deeper layers, testes, or epididymis. It is an important condition to recognize in order to avoid unnecessary surgical exploration. Epidemiol...
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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...
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Acute invasive fungal sinusitis

Acute invasive fungal sinusitis is the most aggressive form of fungal sinusitis. It is seen particularly in immunocompromised patients and is the source of significant morbidity and mortality. It should be distinguished from the other two forms of invasive fungal sinusitis, chronic invasive fung...
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Acute liver failure

Acute liver failure (ALF), also known as fulminant hepatic failure, refers to sudden severe liver dysfunction from injury without underlying chronic liver disease (CLD), although sometimes it presents as decompensation of unknown chronic liver disease.  Epidemiology Acute liver failure is rare...
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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...
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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 lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a malignant disorder of the bone marrow characterized by the proliferation of the lymphoid progenitor cells. Epidemiology Acute lymphoblastic leukemia is the commonest form of childhood leukemia, accounting for ~80% of pediatric leukemia cases 1. In adults...
Article

Acute mastoiditis

Acute mastoiditis refers to a suppurative infection of the mastoid air cells. It is the most common complication of acute otitis media. Terminology In acute otitis media, an inflammatory middle ear effusion is present that can freely move into the mastoid air cells. Consequently, some authors ...
Article

Acute mesentric ischemia

Acute mesenteric ischemia accounts for the majority (around 95%) of cases with mesenteric ischemia and comprises of arterial occlusive mesenteric ischemia (60-85%) embolic acute mesenteric ischemia (EAMI) thrombotic acute mesenteric ischemia (TAMI) non-occlusive mesenteric ischemia (NOMI) (1...
Article

Acute myeloid leukemia

Acute myeloid leukemia (AML), also referred to as acute myelogenous leukemia, is a hematological malignancy characterized by the abnormal clonal proliferation of immature myeloid precursors (myeloblasts) or poorly differentiated cells of the hematopoietic system. It primary infiltrates the bone ...
Article

Acute necrotic collection

Acute necrotic collections (ANCs) are an early, local complication of necrotizing pancreatitis. Terminology The following are the latest terms according to the updated Atlanta classification to describe fluid collections associated with acute pancreatitis 1,2: fluid collections in interstitia...
Article

Acute necrotizing encephalopathy

Acute necrotizing encephalopathy, also referred as acute necrotizing encephalopathy of childhood, is a rare type of encephalopathy characterized by multiple bilateral brain lesions, mainly involving the thalami, but also the putamina, internal and external capsules, cerebellar white matter, and ...
Article

Acute otitis externa

Acute otitis externa (AOE), also known as "swimmer's ear", is inflammation of the external auditory canal (EAC) that can involve the pinna as well. Bacterial infection, most commonly with Pseudomonas aeruginosa, is responsible for the overwhelming majority of cases. It is a common condition. Ep...
Article

Acute pancreatitis

Acute pancreatitis (plural: pancreatitides) is an acute inflammation of the pancreas and is a potentially life-threatening condition. The diagnosis of acute pancreatitis is made by fulfilling two of the following three criteria 8: acute onset of persistent, severe epigastric pain (i.e. pain co...
Article

Acute pancreatitis (summary)

This is a basic article for medical students and other non-radiologists Acute pancreatitis refers to acute inflammation of the pancreas and is a potentially life-threatening condition. Reference article This is a summary article; read more in our article on acute pancreatitis. Summary anato...
Article

Acute pelvic pain

Acute pelvic pain is a common presenting symptom to the emergency department and radiologist. Pelvic ultrasound with transabdominal and endovaginal approaches is usually the first line imaging modality. Clinical presentation non-cyclic pain pain of <3 months duration Patients also often pres...
Article

Acute peripancreatic fluid collection

Acute peripancreatic fluid collections (APFC) are an early complication of acute pancreatitis that usually develop in the first four weeks. After four weeks, the term pseudocysts is used. The absence of necrosis differentiates APFCs from acute necrotic collections (ANC), that is, APFCs occur in ...
Article

Acute phlegmonous esophagitis

Acute phlegmonous esophagitis is a very rare form of esophagitis in which there is a diffuse bacterial infection within the submucosa of the esophagus 1. Terminology Usually there is co-infection of the stomach (phlegmonous gastritis), and if both the stomach and esophagus are involved it is c...
Article

Acute promyelocytic leukemia

Acute promyelocytic leukemia (APML) is a distinct subtype of acute myeloid leukemia. Pathology Genetics It is defined by a balanced translocation between chromosomes 15 and 17 resulting in fusion of the promyelocytic leukemia gene (PML) on chromosome 15 with the retinoic acid receptor alpha g...
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 pyelonephritis

Acute pyelonephritis (plural: acute pyelonephritides) is a bacterial infection of the renal pelvis and parenchyma most commonly seen in young women. It remains common and continues to have significant morbidity in certain groups of patients. Epidemiology The incidence of acute pyelonephritis p...
Article

Acute radiation syndrome

Acute radiation syndrome, also called radiation poisoning or radiation sickness, refers to the signs and symptoms associated with the acute effects of high-dose rates of ionizing radiation (usually over 0.5 Gy) through either whole body or partial body irradiation.  Epidemiology The exact prev...
Article

Acute renal transplant rejection

Acute renal transplant rejection is a renal transplant complication that occurs within <5-7 days of the placement of the transplant. Although part of a spectrum of closely-related rejection disorders, the term is meant to distinguish this type of rejection from chronic renal transplant rejection...

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