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.

2,039 results found
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14-3-3 protein

14-3-3 protein is found in the cerebrospinal fluid (CSF), and is currently used to help identify patients with sporadic Creutzfeldt-Jakob disease (sCJD).  In diagnosing sCJD, the sensitivity of 14-3-3 protein is 92% and its specificity is 80% 1. A negative 14-3-3 assay may be helpful in reducin...
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1p19q codeletion

1p19q codeletion stands for the combined loss of the short arm chromosome 1 (i.e. 1p) and the long arm of chromosome 19 (19q) and is recognised as a genetic marker predictive of therapeutic response to both chemotherapy and combined chemoradiotherapy and overall longer survival in patients with ...
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2-hydroxyglutarate

2-hydroxyglutarate is a metabolite that accumulates in the brains of patients with IDH-1 mutated (IDH-1 positive) brain tumours, particularly diffuse low-grade gliomas. Although not in widespread clinical use, it is likely that 2-hydroxyglutarate, which resonates at 2.25 ppm, will be able to be ...
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Adenoma-carcinoma sequence

The adenoma-carcinoma sequence refers to a stepwise pattern of mutational activation of oncogenes (e.g. K-ras) and inactivation of tumour suppressor genes (e.g. p53) that results in cancer. An oncogene is a gene that has the potential to cause cancer. In tumour cells, these are often mutated or ...
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AFP reduction

Human AFP (alpha-fetoprotein) reduction is seen in pregnancy where it can be associated with:  certain chromosomal anomalies Down syndrome Turner syndrome trisomy 13 trisomy 18 Cornelia de-Lange syndrome 2
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Alpha thalassemia/mental retardation syndrome X-linked (ATRX)

Alpha-thalassemia/mental retardation syndrome X-linked (ATRX) is an important genomic marker of gliomas. Loss/mutation of ATRX is almost never seen in patients with 1p/19q co-deletion (i.e. they are essentially mutually exclusive). Oligodendrogliomas will, therefore, have intact ATRX and 1p19q c...
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Alzheimer type I glia

Alzheimer type I glia are a type of glial cell. They are large multinucleated astrocytes encountered in glial tumours and progressive multifocal leukoencephalopathy (PML) 1. 
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Alzheimer type II glia

Alzheimer type II glia are a type of glial cell. They are a pathological reactive astrocyte seen in the brain, unrelated to Alzheimer disease. They are seen most frequently in Wilson disease, but also in other systemic metabolic disorders, particularly those with elevated ammonia levels, typical...
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Angiomyofibroblastoma-like tumour of scrotum

Angiomyofibroblastoma-like tumour of scrotum is a rare well-defined slow growing mesenchymal extratesticular nonepididymal tumour which rarely seen in perineum and scrotum of older male patients. A similar tumour can occur in the vulval region in females. Epidemiology  In males, they are seen ...
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Angiosarcoma of breast

Breast angiosarcomas are a rare vascular breast malignancy. Epidemiology As primary tumours of the breast, they account for ~0.04% 2 of all breast cancers and tend to occur in younger women, 3rd to 4th decades. Secondary angiosarcoma has an estimated incidence of ~0.09-0.16% and occurs in olde...
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Ankylosing spondylitis

Ankylosing spondylitis (less commonly known as Bechterew disease and Marie Strümpell disease) is a seronegative spondyloarthropathy, which as the name suggests, results in fusion (ankylosis) of the spine and sacroiliac (SI) joints, although involvement is also seen in large and small joints.  E...
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Annulo-aortic ectasia

Annulo-aortic ectasia refers to a proximal dilatation of the aortic root at the level of the aortic annulus, it is also the same level of the sinus of Valsalva. Pathology Annulo-aortic ectasia occurs with connective tissue diseases such as Marfan disease and Ehlers-Danlos syndrome. It is a cys...
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Anomalous left coronary artery from the pulmonary artery

Anomalous left coronary artery from the pulmonary artery (ALCAPA), also known as Bland-White-Garland syndrome (BWG), is a rare congenital coronary artery anomaly and is considered one of the most serious of such anomalies. There are two forms based on onset of disease each of which has differen...
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Anterior cerebral artery (ACA) infarct

Anterior cerebral artery (ACA) territory infarcts are much less common than either middle or posterior cerebral artery territory infarcts.  Epidemiology ACA territory infarcts are rare, comprising ~2% of ischaemic strokes 1,2.  Clinical presentation ACA stroke syndrome presents as 1,2,3: dy...
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Anterior cruciate ligament ganglion cyst

Anterior cruciate ligament (ACL) ganglion cysts, commonly referred to simply as ACL cysts, along with ganglion cysts arising from the alar folds that cover the infrapatellar fat pad, make up the vast majority of intra-articular ganglion cysts of the knee. Epidemiology These are uncommon findin...
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Anterior cruciate ligament mucoid degeneration

Anterior cruciate ligament (ACL) mucoid degeneration, along with tears and anterior cruciate ligament ganglion cysts, is a relatively common cause of increased signal within the anterior cruciate ligament (ACL). The appearance can mimic acute or chronic interstitial partial tears of the ACL. Ho...
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Anterior inferior iliac spine avulsion injury

Anterior inferior iliac spine (AIIS) avulsion injuries are one of the six main types of pelvic apophyseal avulsion fractures.  Epidemiology As with many pelvic avulsion injuries, they most often occur in adolescents (mostly between the ages 14-17). There is a slight male predilection and they ...
Article

Anterior talofibular ligament injury

Anterior talofibular ligament (ATFL) injury is the most common of the ligament injuries that can occur as part of the lateral ligament complex injuries 2. The injuries can comprise of either soft tissue tears, avulsion fractures or both. Pathology ATFL injuries typically occurs with an inversi...
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Anterior temporal lobe perivascular spaces

Anterior temporal lobe perivascular spaces are recently recognised special variants of tumefactive perivascular spaces, which can mimic cystic tumours with surrounding oedema. Epidemiology A predilection for women has been reported 1. Age range is wide, from 24 to 86 years old reported 1. Cli...
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Anti NMDA receptor encephalitis

Anti N-methyl-D-aspartic acid (NMDA) receptor encephalitis is an autoimmune encephalitis with antibodies against the NMDA receptors. It is sometimes considered a form of autoimmune limbic encephalitis. It usually affects young patients particularly young females, in about 60% of whom ovarian ter...
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Antithrombin III deficiency

Antithrombin (AT) III deficiency (now simply called antithrombin deficiency) refers to a congenital lack of an endogenous anticoagulant called antithrombin. Epidemiology Antithrombin deficiency is considered the least common of the three main anticoagulant deficiencies (the other two being pro...
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Antopol-Goldman lesion

Antopol-Goldman lesions are very rare presentations of subepithelial haemorrhage in the renal pelvis, presenting as discrete mass-like haematomas. Pathology The cause of these lesions is uncertain, although non-steroidal anti-inflammatory drug (NSAID) overuse, trauma, and amyloidosis have been...
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Antrochoanal polyp

Antrochoanal polyps (ACP) are solitary sinonasal polyps that arise within the maxillary sinus.  They pass through and enlarge the sinus ostium and posterior nasal cavity to the nasopharynx.  Similar polyps can arise in the sphenoid sinus extending into the nasopharynx: these are termed sphenoch...
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Aortic aneurysms

The broad term aortic aneurysm is usually reserved for pathology discussion. More specific anatomic and radiologic discussion is based on the location of the aneurysm: thoracic aortic aneurysm abdominal aortic aneurysm
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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...
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Aortic intramural haematoma

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

Aortic pseudoaneurysms typically occur as a result of trauma. They can be acute or chronic. Pathology Aortic pseudoaneurysms are contained ruptures of the aorta in which the majority of the aortic wall has been breached, and luminal blood is held in only by a thin rim of the remaining wall or ...
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Aortitis

Aortitis refers to a general descriptor that involves a broad category of infectious and non-infectious conditions where there is abnormal inflammation (i.e. vasculitis) of the aortic wall. Clinical presentation The presentation is non-specific with fever, pain and weight loss.  Pathology  A...
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Aorto-caval fistula

Aorto-caval fistula is a rare and devastating complication of abdominal aortic aneurysm (AAA), wherein the aneurysm erodes into the inferior vena cava. Epidemiology Spontaneous rupture of an AAA into the adjacent vena cava occurs in <1% of all aneurysms and in ~3% of ruptured aortic aneurysms ...
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Aorto-enteric fistula

Aorto-enteric fistulation is an uncommon catastrophic cause of gastrointestinal haemorrhage. Aortic fistulas can be primary (associated with an abdominal aortic aneurysm) or secondary (associated with graft repairs).  Epidemiology The annual incidence of primary aorto-enteric fistulas is thoug...
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Aorto-iliac occlusive disease

Aorto-iliac occlusive disease refers to complete occlusion of the aorta distal to the renal arteries. Terminology When the clinical triad of impotence, pelvis and thigh claudication, and absence of the femoral pulses are present, it may also be called Leriche syndrome, which usually affects yo...
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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...
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Apocrine carcinoma of the breast

Apocrine carcinoma of the breast is a rare variant of breast cancer. The diagnosis is mainly pathological as it is difficult to differentiate from other forms of breast cancer on imaging. Epidemiology It accounts for about 4% of all the cases. It is seen most often in females in the age group ...
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Apocrine metaplasia of the breast

Apocrine metaplasia of the breast is a benign breast condition and is sometimes considered part of or associated with fibrocystic change. It is a common finding in the female breast particularly after the age of 25 and many regard it as a normal component of the breast. Epidemiology Seen mostl...
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Appendiceal carcinoid

Appendiceal carcinoids are rare overall but represent the most common tumour of the appendix. The appendix is also one of the most common (but not the most common) locations for gastrointestinal carcinoid tumours.  Clinical presentation Appendiceal carcinoids can present as the obstructive cau...
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Appendiceal intussusception

Appendiceal intussusception happens when appendix segment is pulled into itself or into the cecum. This condition can mimic various chronic and acute abdominal conditions, with an important entity to be recognized, since it could be mistaken as a cecal mass. Epidemiology Appendiceal intussusce...
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Appendiceal mucinous cystadenoma

Appendiceal mucinous cystadenomas are rare tumours of the appendix. They are considered a benign equivalent of an appendiceal mucinous cystadenocarcinoma. Epidemiology They may be histologically present in around 0.3% appendiceal resection specimens 3.  Clinical presentation A commonly descr...
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Appendiceal mucocoele

Appendiceal mucocoeles occur when there is abnormal accumulation of mucus within the appendix. The tenacious and viscous mucus causes obstruction of the appendiceal neck and results in dilatation of the lumen. Epidemiology The reported prevalence at appendectomy is 0.2-0.3%. They are thought t...
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Appendicitis

Appendicitis is inflammation of the vermiform appendix. It is a very common condition in general radiology practice and is one of the main causes of abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis. Epidemiology Acute appendicitis is typically a dis...
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Appendicolith

An appendicolith is a calcified deposit within the appendix. They are present in a large number of children with acute appendicitis and may be an incidental finding on an abdominal radiograph or CT. Incidence may be increased among patients with a retrocaecal appendix. Overall they are seen in 1...
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Arachnoiditis

Arachnoiditis is a broad term encompassing inflammation of the meninges and subarachnoid space. Terminology Arachnoiditis affecting the cauda equina may be referred to as spinal/lumbar adhesive arachnoiditis.  Clinical presentation Lumbar spine arachnoiditis can result in leg pain, sensory c...
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Arteriosclerosis

Arteriosclerosis is defined by thickening and loss of elasticity of the arterial walls. There are three patterns (arteriosclerosis is used as a generic term for all patterns above): atherosclerosis: large and medium-sized arteries Monckeberg medial calcific sclerosis: muscular arteries arter...
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Arteriovenous fistula

An arteriovenous fistula (AVF) is an abnormal connection between an adjacent artery and vein. Unlike an arteriovenous malformation (AVM), these are frequently acquired lesions, rather than developmental abnormalities. Pathology AVFs have a number of etiologies. They can be iatrogenic in origin...
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Asbestosis

Asbestosis refers to later development of diffuse interstitial fibrosis secondary to asbestos fibre inhalation and should not be confused with other asbestos related diseases. Epidemiology Asbestosis typically occurs 10-15 years following the commencement of exposure to asbestos and is dose re...
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Ascending aortic aneurysm

Ascending aortic aneurysms are the most common subtype of thoracic aortic aneurysms, and may be true or false injuries.  Epidemiology Ascending aortic aneurysms represent 60% of thoracic aortic aneurysms.  Clinical presentation Typically ascending aortic aneurysms are an incidental finding a...
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Ascending transtentorial herniation

Ascending transtentorial herniation is a situation where space occupying lesions in the posterior cranial fossa cause superior displacement of superior parts of the cerebellum through the tentorial notch.  Clinical presentation nausea and/or vomiting  rapid progression toward decreased level ...
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Ascites

Ascites is defined as an abnormal amount of intraperitoneal fluid. Clinical presentation Patients with large volume of ascites can present with abdominal distension (which may be painful), nausea, vomiting, dyspnoea and peripheral oedema 7, 9. Pathology Ascitic fluid is traditionally charact...
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Aspergillus clavatus

Aspergillus clavatus is one of the species of Aspergillus that can cause pathology in humans. It is allergenic and causes a hypersensitivity pneumonitis called malt-workers lung. See also Aspergillus Aspergillus fumigatus Aspergillus flavus Aspergillus clavatus
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Asteroid hyalosis

Asteroid hyalosis is a degenerative condition of the eye where there is accumulation of calcium soaps in vitreous chamber. Epidemiology The prevalence increases with age from 0.2% 43-54 year olds to 2.9% in 75-86 year olds. The overall prevalence is 1.2%. It is more commonly unilateral and fav...
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Asthma

Asthma is a relatively common condition that is characterised by at least partially reversible inflammation of the airways and reversible airway obstruction due to airway hyper-reactivity. It can be acute, subacute or chronic. Epidemiology Asthma is one of the most common chronic diseases in t...
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Astroblastoma

Astroblastomas are rare glial tumours usually found in the cerebral hemispheres of young adults and children.  Epidemiology They occur at all ages range from early childhood to 6th decade but are most commonly seen in children, adolescents, and young adults with a mean age between 10-30 years ...
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Astrocytes

Astrocytes are cells of the central nervous system which act as both physical and physiological support for the neurones that are embedded between them. They are particularly abundant in the grey matter, where they are the most abundant glial cells 1. They are highly branched and contribute to ...
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Asymmetrical intrauterine growth restriction

Asymmetrical intrauterine growth restriction is a type of intrauterine growth restriction (IUGR) where some fetal biometric parameters are disproportionately lower than others, as well as falling under the 10th percentile. The parameter classically affected is the abdominal circumference (AC). ...
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Atlanto-occipital dissociation injuries

Atlanto-occipital dissociation (AOD) injuries are severe and include both atlanto-occipital dislocations and atlanto-occipital subluxations. Pathology The tectorial membrane and alar ligaments provide the most the stability to the atlanto-occipital joint, and injury to these ligaments results ...
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Atretic parietal cephalocoele

Atretic parietal cephalocoeles (APC) also known as atretic cephalocele, refers to small subscalp lesions that consist of dura, fibrous tissue, and dysplastic brain tissue. Epidemiology Common presentation in infants and young children.  Clinical presentation Palpable midline parietal soft ti...
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Atrial septal defect

Atrial septal defects (ASD) are the second most common congenital heart defect after ventricular septal defects and the most common to become symptomatic in adulthood. They are characterised by an abnormal opening in the atrial septum allowing communication between the right and left atria. Due...
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Atrio-oesophageal fistula

Atrial-oesophageal fistulas are rare pathological connections between the left atrium and the oesophagus.  Clinical presentation The presentation is non-specific. Patients may complain of fever, malaise, dysphagia or present with neurological symptoms 3.  Pathology The chief cause of atrial-...
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Atrophic gastritis

Atrophic gastritis is a chronic condition of autoimmune and non-autoimmune aetiology.  Pathology Two types of atrophic gastritis have been described 1-3: type A: autoimmune gastric body and fundus atrophy secondary to antiparietal cell antibodies decreased secretion of acid and intrinsic fa...
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Atypical ductal hyperplasia

Atypical ductal hyperplasia (ADH) is a histologically borderline lesion that has some, but not all the features of ductal carcinoma in situ (DCIS). Sometimes the distinction between ADH and DCIS is simply on the basis of the number of ducts involved.  Pathology Atypical ductal hyperplasia is a...
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Atypical lobular hyperplasia

Atypical lobular hyperplasia (ALH) is a pre-malignant lesion of the breast which falls at the milder end of the spectrum of lobular neoplasia. It is therefore considered a part of borderline breast disease.  Clinical presentation It is usually asymptomatic and mammographically occult, and is i...
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Atypical meningioma

Atypical meningioma refers to a more aggressive form of meningioma and denotes a WHO grade II tumour (along with two histological variants clear cell meningioma and chordoid meningioma). Atypical meningiomas account for 20-30% of all meningiomas 1,3.  It should be noted that epidemiology, clini...
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Atypical pneumonia

Atypical pneumonia refers to the radiological pattern associated with patchy inflammatory changes, often confined to the pulmonary interstitium, most commonly associated with atypical bacterial aetiologies such as Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophilia. Viral...
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Atypical small acinar proliferation

Atypical small acinar proliferations (ASAP) are premalignant lesions of the prostate, which can be found in as many as 5% of prostate biopsies. They are suspicious glands without adequate histologic atypia to establish a definitive diagnosis of prostate cancer. Some studies showed that there is ...
Article

Atypical teratoid/rhabdoid tumour

Atypical teratoid/rhabdoid tumours (AT/RTs) are an uncommon WHO Grade IV tumour, which in the vast majority of cases occurs in young children less than two years of age. It most frequently presents as a posterior fossa mass.  AT/RTs were until relatively recently classed as medulloblastomas, al...
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Autoimmune encephalitis

Autoimmune encephalitis (also known as autoimmune limbic encephalitis) is an antibody-mediated autoimmune-mediated inflammation of the brain, typically involving the limbic system, although all parts of the brain can be involved.  Autoimmune encephalitis can be divided broadly into two groups, ...
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Autoimmune hepatitis

Autoimmune hepatitis is a rare type of chronic hepatitis, currently classified as "type 1" or "type 2". It may eventually lead to cirrhosis. The role of imaging is primarily to exclude other diagnoses and evaluate for complications. Epidemiology It may occur in children or adults, but most pat...
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Autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis associated with autoimmune manifestations on clinical, histological, and laboratory grounds 1. Distinguishing this entity from other forms of chronic pancreatitis (such as alcohol-induced) is important as steroid treatment is effec...
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Autosomal dominant osteopetrosis

Autosomal dominant osteopetrosis is the less severe type of osteopetrosis and should be considered and compared with the other subtype: autosomal recessive osteopetrosis. The autosomal dominant (AD) type is less severe than its autosomal recessive (AR) mate. Hence, it is also given the name "ben...
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Autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD), also sometimes more vaguely referred to as "adult polycystic kidney disease", is as the name would suggest, a hereditary form of adult cystic renal disease.  Epidemiology Autosomal dominant polycystic kidney disease is one of the most commo...
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Autosomal recessive polycystic kidney disease

Autosomal recessive polycystic kidney disease (ARPKD) is one of many paediatric cystic renal diseases. On imaging, it usually presents on ultrasound with enlarged echogenic kidneys with multiple small cysts. Liver involvement with coarse echotexture, biliary tract cystic changes, and portal hyp...
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Autosplenectomy

Autosplenectomy denotes spontaneous infarction of the spleen with resulting hyposplenism. Epidemiology Autosplenectomy is most frequently encountered in patients with homozygous sickle cell disease, although it has also been reported in pneumococcal septicaemia 1, and SLE 2. The demographics t...
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Avascular necrosis

Avascular necrosis (AVN), or more correctly "osteonecrosis", is a generic term referring to an ischaemic death of the constituents of bone. AVN has a wide variety of causes and can affect nearly any bone in the body. Most sites of involvement have an eponym associated with avascular necrosis of ...
Article

Avascular necrosis of the hip

Avascular necrosis of the hip is more common than other sites, presumably due to a combination of precarious blood supply and high loading when standing.  Clinical presentation The most common presenting symptom is a pain in the region of affected hip, thigh, groin, and buttock. Although few p...
Article

Azoospermia

Azoospermia refers to complete absence of sperm in the semen. It accounts for 5-10% of male infertility 1. Pathology It can be obstructive or non-obstructive, e.g. primary testicular failure. This differentiation is of utmost importance, as obstructive azoospermia can be corrected by surgical ...
Article

Baker cyst

Baker cysts (or popliteal cysts) are fluid-filled distended synovial-lined bursa arising in the popliteal fossa between the medial head of the gastrocnemius and the semimembranosus tendons via a communication with the knee joint. They are usually located at or below the joint line. Epidemiology...
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Balo concentric sclerosis

Balo concentric sclerosis (BCS) is a rare and severe monophasic demyelinating disease, considered a subtype of multiple sclerosis, appearing as a rounded lesion with alternating layers of hyper and hypoattenuation giving it a characteristic 'bullseye' or 'onion bulb' appearance 1,9.  Clinical p...
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BALT lymphoma

BALT lymphoma is an abbreviated term for bronchus-associated lymphoid tissue lymphoma. These neoplasms fall under the broader umbrella of mucosa associated lymphoid tissue (MALT) lymphomas. It is sometimes considered a type of primary pulmonary lymphoma. Clinical presentation Up to half of pat...
Article

Band heterotopia

Band heterotopia, also known as double cortex syndrome, is a form of diffuse grey matter heterotopia affecting almost only women. Refractory epilepsy is present in nearly all affected patients, with partial complex and atypical absence epilepsy being the most common syndromes. On imaging, this ...
Article

Bankart lesion

Bankart lesions are a common complication of anterior shoulder dislocation and are frequently seen in association with a Hill-Sachs lesion. Pathology They result from detachment of the anterior inferior labrum from the underlying glenoid as a direct result of the anteriorly dislocated humeral ...
Article

Barrett oesophagus

Barrett oesophagus is a term for intestinal metaplasia of the oesophagus. It is considered the precursor lesion for oesophageal adenocarcinoma. Epidemiology Barrett oesophagus is thought to have a prevalence of 3-15% in patients with reflux oesophagitis. Mean age at diagnosis is 55 years old 5...
Article

Bartholin gland abscess

Bartholin gland abscess is a complication that may result from an infected Bartholin gland cyst.  Radiographic features Abscesses are usually in a similar location to Bartholin gland cysts. Features of Bartholin gland abscess are otherwise similar to Bartholin gland cyst described in separate ...
Article

Basal ganglia haemorrhage

Basal ganglia haemorrhage is a common form of intracerebral haemorrhage, and usually as a result of poorly controlled long-standing hypertension. The stigmata of chronic hypertensive encephalopathy are often present (see cerebral microhaemorrhages). Other sites of hypertensive haemorrhages are ...
Article

Basilar artery hypoplasia

Basilar artery hypoplasia is a rare vascular anomaly of the basilar artery. Pathology Associations Basilar artery hypoplasia is usually accompanied by one or more fo the following: persistent carotid-vertebrobasilar anastomoses hypoplastic V4 segments of the vertebral arteries unilateral o...
Article

Baxter neuropathy

Baxter neuropathy is a nerve entrapment syndrome resulting from the compression of the inferior calcaneal nerve (Baxter nerve). The inferior calcaneal nerve is the first branch of the lateral plantar nerve which courses in a medial to lateral direction between the abductor hallucis muscle and t...
Article

Behçet disease

Behçet disease is a multi-systemic and chronic inflammatory vasculitis of unknown aetiology. Epidemiology The mean age at which Behçet disease occurs is 20-30 years. The disease is most prevalent in the Mediterranean region, Middle East and East Asia. The highest incidence has been reported in...
Article

Bell palsy

Bell palsy, also known as idiopathic peripheral facial paralysis, is characterised by rapid onset facial nerve paralysis, often with resolution in 6-8 weeks. As there are numerous causes of facial nerve palsy, many of which can be acute in onset, it is currently a diagnosis of exclusion supporte...
Article

Benign enlargement of the subarachnoid space in infancy

Benign enlargement of the subarachnoid spaces in infancy (BESS or BESSI) also known as benign external hydrocephalus (BEH) is, as the name implies, a benign enlargement of subarachnoid spaces seen in infancy. It usually involves the frontal lobe subarachnoid spaces, and it is characterised clini...
Article

Benign fibrous histiocytoma of bone

Benign fibrous histiocytoma is closely related to fibroxanthoma of bone, is a rare lesion usually occurring in the skin where it is known as dermatofibroma. Clinical presentation Typically presents with pain, and most often in the third decade. Pathology Only a few case reports have been pub...
Article

Benign lymphoepithelial lesions

Benign lymphoepithelial lesions (BLL or BLEL), also misleadingly known as AIDS-related parotid cysts (ARPC), are mixed solid and cystic lesions that enlarge the parotid glands, and are usually associated with cervical lymph node enlargement, and nasopharyngeal lymphofollicular hyperplasia. Epid...
Article

Benign metastasising leiomyoma

Benign metastasising leiomyoma (BML) is a rare metastatic phenomenon that is observed when a pelvic leiomyoma is present. Epidemiology Women who have undergone hysterectomy for leiomyomas are most commonly affected. Clinical presentation Patients are usually asymptomatic at presentation. A h...
Article

Benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is an extremely common condition in elderly men and is a major cause of bladder outflow obstruction.  Terminology The term benign prostatic hypertrophy was formerly used for this condition, but since there is actually an increase in the number of epithelial a...
Article

Beta catenin mutated hepatic adenoma

Beta catenin mutated hepatic adenomas are a genetic and pathologic subtype of hepatic adenoma. Their appearance and prognosis are different than other subtypes. Epidemiology They are the least common subtype of hepatic adenoma (10-15%). They occur more frequently in men and are associated with...
Article

Bezold abscess

A Bezold abscess is a complication of acute otomastoiditis where the infection erodes through the cortex medial to the attachment of sternocleidomastoid , at the attachment site of the posterior belly of the digastric muscle, and extends into the infratemporal fossa. Due to it being deep to the ...

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