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.

967 results found
Article

Splenic amyloidosis

Splenic amyloidosis is rare as an isolated entity. Most often it is associated with either systemic amyloidosis or hepatic amyloidosis. Epidemiology In general, splenic involvement in amyloidosis is rather frequent (5-10% of cases 6,7). Clinical presentation Symptoms include abdominal mass a...
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Splenic calcification

Splenic calcifications can occur is various shapes and forms and can occur from a myriad of etiological factors. The usual calcification observed in radiographs are the multiple, miliary form presenting numerous small rounded densities averaging from three to five millimeters in diameter where ...
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Splenic cyst

Splenic epithelial cysts, also referred as splenic epidermoid cysts or primary splenic cysts, are unilocular fluid lesions with thin and smooth walls and no enhancement. They represent ~20% of cysts found in the spleen, and are usually an innocuous incidental imaging finding. Note that most (~8...
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Splenic haemangiomatosis

Splenic haemangiomatosis involves multiple, diffuse splenic hemangiomas replacing its entire parenchyma. It is a very rare entity. Pathology It can occur as a manifestation of systemic angiomatosis or, less commonly, confined to the spleen (diffuse isolated splenic haemangiomatosis). There is ...
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Splenic lesions and anomalies

There are a number of splenic lesions and anomalies: Congenital anomalies accessory spleen wandering spleen asplenia polysplenia splenogonadal fusion retrorenal spleen Mass lesions Benign mass lesions splenic cyst (mnemonic) splenic pseudocyst splenic hemangioma: commonest benign spl...
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Splenic pseudocyst

Splenic pseudocysts, also referred as secondary splenic cysts, are acquired cystic lesions not delineated by a true epithelial wall. They represent the majority of the splenic cystic lesions, corresponding to approximately 80% of them (c.f. splenic epithelial cysts). The main causes are:  splen...
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Splenomegaly

Splenomegaly refers to enlargement of the spleen. The upper limit of normal adult splenic length is traditionally cited at 12 cm, but lengths upwards of 14 cm can be seen in normal, taller males 7. Massive splenomegaly is variably defined, including when the spleen is 5 standard deviations abov...
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Spontaneous nipple discharge

Spontaneous nipple discharge in a non lactating breast can result from many causes which include: papillary lesions of breast: present in ~35-50% of cases with spontaneous nipple discharge intraductal papilloma fibrocystic change ductal carcinoma in situ: 5-21%
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Spontaneous splenic rupture

Spontaneous splenic rupture (SSR) (or atraumatic splenic rupture) is rare, especially when compared to traumatic splenic rupture.  Pathology The pathogenesis of atraumatic splenic rupture is not well understood. Splenomegaly is present in almost all patients (~95%), although rupture of normal ...
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Sports injuries - cricket

Cricket is a popular game in Commonwealth countries. Sports injuries in this game can be associated with three positional aspects of the game: bowling, batting or fielding. Radiologists should know the different kind of injuries related to this game for a better clinical association. Injuries ca...
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Sports injuries: overhead elbow

Overhead elbow sports injuries are a group of pathologies seen in sports activities with overhead throwing or strokes, e.g. tennis, volleyball, baseball, javelin throwing. There has been a tremendous increase in the number of participants in these sports activities worldwide. Pathology During ...
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Sports injuries: snowsports

Snowsport injuries cover a broad range of activities from alpine or Nordic skiing, snowboarding, and recreational play (e.g. tobogganing, tubing).  Epidemiology Snowsports are popular with over 70 million people globally participating each year 1. While the injury rate varies depending on loca...
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Sprue

Sprue is the collective term for the malabsorptive gastrointestinal enteropathies although it may be used to refer directly to tropical sprue. It is composed of two entities: tropical sprue non-tropical sprue / celiac disease In each, the radiologic features are not sensitive enough to confir...
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Storage disorders

Storage disorders comprise a bewildering collection of inherited metabolic conditions which share the accumulation of a metabolite within various cells in the body due to dysfunction of specific enzymes or transport proteins. Accumulation of metabolites eventually results in cellular and/or orga...
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Stroke in children and young adults

Brain ischemia/infarction in children and young adults can result from several causes. embolic phenomena cyanotic heart disease cardiomyopathies mitral valve prolapse Osler-Weber-Rendu syndrome arterial dissection trauma spontaneous fibromuscular dysplasia Marfan syndrome Ehlers Danlo...
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Subacromial impingement

Subacromial impingement is by far the most common form of shoulder impingement and occurs secondary to attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa. Pathology Etiology os acromiale type III acromion acromioclavicular degenerative disease thick...
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Subarachnoid FLAIR hyperintensity

There are a wide range of causes for subarachnoid FLAIR hyperintensity, both pathological and artifactual.  Differential diagnosis Pathological causes subarachnoid hemorrhage meningitis leptomeningeal carcinomatosis FLAIR vascular hyperintensities in acute stroke 1,4,8 moyamoya disease m...
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Subcutaneous abscess

A subcutaneous abscess is a manifestation of a spectrum of soft tissue skin infection which includes cellulitis and necrotizing fasciitis. It is a form of abscess which lies within the dermis and subdermal cutaneous layers. Along with dental abscesses, subcutaneous abscesses are the most common ...
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Subcutaneous calcification (differential)

Subcutaneous calcification can be associated with a number of disorders. The list includes: dermatomyositis Ehlers-Danlos syndrome pseudoxanthoma elasticum basal cell nevus syndrome subcutaneous lipodystrophy venous thrombosis as a manifestation of systemic lupus erythematosus varicose v...
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Subdiaphragmatic free gas

Subdiaphragmatic free gas is one of the ways of detecting presence of free intraperitoneal gas (i.e. pneumoperitoneum). It is the presence of free, extraluminal gas in the anterior subhepatic space.  Radiographic features Plain radiograph Subdiaphragmatic free gas is well appreciated as the g...
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Subluxed facet joint

Subluxed facet joint is the mildest form of facet dislocation in which the ligamentous injury leads to partial uncovering of facet joint (c.f. complete uncovering in perched facet). This results in mild anterior displacement of one vertebral body on another (anterolisthesis).
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Subperiosteal bone resorption

Subperiosteal bone resorption is the most consistent and specific finding of hyperparathyroidism and is virtually pathognomonic of the condition. Radiographic features While the terminal tufts of the phalanges are the most commonly involved bones, many others are involved: tufts of the distal...
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Subpulmonic effusion

Subpulmonic effusions are a pleural effusion that can be seen only on an erect projection. Rather than layering laterally and blunting the costophrenic angle, the pleural fluid lies almost exclusively between the lung base and the diaphragm. Radiographic features Plain radiograph The fluid ca...
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Subsegmental atelectasis

Subsegmental atelectasis is a descriptive term for a minor peripheral form of lung atelectasis. Terminology Some authors also term it discoid atelectasis or plate-like atelectasis due to its appearance. Pathology It is usually due to a lack of adequate inspiration, and not due to any underly...
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Substernal goiter

Substernal goiter is a goiter (enlarged thyroid gland) with intrathoracic extension. It remains unclear which goitres are to be termed substernal, but a recently proposed definition is a goiter that requires mediastinal exploration and dissection for complete removal or an intrathoracic compone...
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Sunburst appearance (bone)

Sunburst appearance is a type of periosteal reaction giving the appearance of a sunburst secondary to an aggressive periostitis. It should not be confused with the sunburst sign of meningioma vascularity.  The sunburst appearance occurs when the lesion grows too fast and the periosteum does not...
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Superficial siderosis

Superficial siderosis is a rare condition which results from the deposition of hemosiderin along the leptomeninges, with eventual neurological dysfunction. On imaging, it is classically characterized on MRI as a rim of low signal coating the surface of the brain or spinal cord, particularly not...
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Superficial thrombophlebitis

Superficial thrombophlebitis, also called superficial venous thrombosis (SVT), is a pathological condition characterized by the presence of a thrombus in the lumen of a superficial vein, accompanied by inflammatory reaction of adjacent tissues. Terminology Some authors however reserve the term...
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Supernumerary ribs

Supernumerary ribs occur most commonly as a cervical rib arising from C7 or a lumbar rib arising from L1. In extremely rare situations, there can be sacral, coccygeal, intrathoracic, or aberrant lumbar ribs 3. Rarely supernumerary ribs (cervical and lumbar ribs aside) have been found as 'normal'...
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Superscan

Superscan is intense symmetric activity in the bones with diminished renal and soft tissue activity on a Tc99m diphosphonate bone scan. Pathology This appearance can result from a range of etiological factors: diffuse metastatic disease prostatic carcinoma breast cancer transitional cell c...
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Suprasellar cystic lesions

The differential for suprasellar cystic lesions is large and predominantly includes developmental and neoplastic conditions. Differential diagnosis Developmental arachnoid cyst craniopharyngioma Rathke's cleft cyst dermoid cyst epidermoid cyst ependymal cyst enlarged perivascular spaces...
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Surgical sieve (mnemonic)

A surgical sieve is an approach to differential diagnosis that prompts the user to consider various types of pathologies systematically. Various versions of this mnemonic exist: 5I 3-Scotland MIDNIT VINDICATE VITAMIN CDEF NAIVE MD DICTionary Mnemonics 5I 3-Scotland Where "3-Scotland" rel...
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Suspicious breast calcifications

Suspicious breast calcifications are calcifications within the breast that have a morphology and/or distribution on mammography indicating a significant probability of malignancy. These merit further workup and biopsy 1. Radiographic features Technique Some calcifications may be more conspicu...
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Swan neck deformity (fingers)

Swan neck deformity is a deformity of the digits that consists of: hyperextension of the proximal interphalangeal (PIP) joints compensatory flexion of the distal interphalangeal (DIP)  joints Pathology Swan neck deformity is seen in 3,4: rheumatoid arthritis (classical association) post-tr...
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Symmetrical periosteal reaction

There are a large number of causes for a symmetrical periosteal reaction 1,2: chronic venous insufficiency hypertrophic osteoarthropathy physiologic periostitis, most common cause before 6 months old Caffey disease juvenile idiopathic arthritis pachydermoperiostosis congenital syphilis ...
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Syndactyly

Syndactyly (plural: syndactylies) refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly/simple syndactyly) or may involve bone (bony syndactyly/complex syndactyly). Epidemiology The overall estimated incidence is at ~1 per 2,500 to 5,000...
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Syndesmophyte

Syndesmophytes are calcifications or heterotopic ossifications inside a spinal ligament or of the annulus fibrosus.​ They are seen in only a limited number of conditions including:  ankylosing spondylitis ochronosis fluorosis reactive arthritis psoriatic arthritis They can be classified as...
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Syringobulbia

Syringobulbia is a rare entity and refers to a syrinx that extends into the medulla oblongata 1. Terminology Some authors use syringobulbia to refer to a syrinx present in any portion of the brainstem rather than specifically involving the medulla oblongata, and therefore encompassing syringop...
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Syrinx

Syrinx is the collective name given to hydromyelia, syringomyelia, syringobulbia, syringopontia, syringomesencephaly, and syringocephalus. Terminology The use of the general term 'syrinx' has grown out of the difficulty in distinguishing between hydromyelia and syringomyelia using current imag...
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Systemic lupus erythematosus (thoracic manifestations)

Thoracic manifestations of systemic lupus erythematosus can be variable.  For a general discussion, and for links to other system specific manifestations, please refer to the article on systemic lupus erythematosus.  Pathology Pleuropulmonary manifestations pleuritis: considered one of the c...
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Talar dislocation

There are many types of talar dislocation given its multiple articulations: tibiotalar dislocation subtalar dislocation total talar dislocation talonavicular dislocation ​Chopart fracture-dislocation
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Talar fractures

Talar fractures are an uncommon injury, accounting for <5% of all foot fractures. Recognition of the unique talar anatomy is important for correct diagnosis. Pathology Location talar head fractures talar neck fractures talar body fractures talar dome osteochondral fracture posterior talar...
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Tauopathy

Tauopathies are a heterogeneous group of neurodegenerative diseases characterized by abnormal metabolism of tau proteins leading to intracellular accumulation and formation of neurofibrillary tangles (NFT). These neurofibrillary tangles are deposited in the cytosol of neurons and glial cells.  ...
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Telecanthus

Telecanthus represents increased intercanthal distance. It is often used interchangeably with hypertelorism, referring to increased distance between the eyes. Causes and associations trauma: naso-orbito-ethmoidal (NOE) fractures ethnic variation acquired sinus and orbital tumors sinus poly...
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Temporal bone destructive lesions (differential)

Destructive lesions of the temporal bone (petrous pyramid, middle ear and antrum) have a relatively broad differential including 1: lesions affecting petrous pyramid vestibular schwannoma (acoustic neuroma) meningioma glioma neuroma of trigeminal and facial nerve chordoma glomus jugulare ...
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Temporomandibular joint effusion

Temporomandibular joint (TMJ) effusions are unusual in asymptomatic patients, and thus should trigger a careful search for underlying pathology. It usually precedes osteoarthritis of the TMJ. Effusions are seen in: TMJ dysfunction septic arthritis rheumatoid arthritis (RA) Radiographic featu...
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Tension pneumothorax

Tension pneumothoraces occur when intrapleural air accumulates progressively in such a way as to exert positive pressure on mediastinal and intrathoracic structures. It is a life-threatening occurrence requiring both rapid recognition and prompt treatment to avoid a cardiorespiratory arrest. A ...
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Terminal ileitis (differential)

The differential diagnosis for a terminal ileitis is quite extensive, and includes: inflammatory bowel disease Crohn disease (most common) backwash ileitis due to ulcerative colitis infectious colitis Yersinia spp.  Yersinia enterocolitica Yersinia pseudotuberculosis Salmonella spp. ​Sa...
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Terminal tuft mass

There is only a short list of terminal tuft masses, which can arise from the adjacent soft tissues and erode the terminal tuft as well as arising from the terminal tuft itself: epidermal inclusion cyst: history of penetrating trauma tenosynovial giant cell tumor: occur laterally subungual glo...
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Terminal zones of myelination

The terminal zones of myelination are located at the posterior aspect of the lateral ventricles (the peritrigonal regions) and are the only part of the cerebral white matter that may exhibit high T2 signal in a normal brain at 2 years of age, when myelination of cerebral white matter normally be...
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Testicular cancer

Testicular cancers are the most common neoplasm in men between the ages of 20 and 34 years. Epidemiology Testicular cancer is uncommon, accounting for less than 1% of all internal organ malignancies 2. The demographics of affected individuals depends on the age of the histology of the tumor. ...
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Testicular microlithiasis

Testicular microlithiasis (TM) is a relatively common condition that represents the deposition of multiple tiny calcifications throughout both testes.  The most common criterion for diagnosis is that of five microcalcifications in one testicle, although definitions have varied in the past. In t...
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Testicular trauma

Testicular trauma is the third most-common cause of acute scrotal pain and may result in various degree of damage to the testes. Pathology Testicular rupture and testicular ischemia/infarct are two severe complications which need to be ruled out. Other injuries that can occur include 1: testi...
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The four "Ds" of radiology reporting

The four "Ds" of radiology reporting are the basic sequential tasks that a radiologist performs when reporting/reading a case, whether it be in training, the exam environment or in day-to-day clinical practice.  The 4 "Ds" Detect Describe Diagnosis or differential diagnoses Decision By sti...
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Third inflow

Third inflow refers to anatomical variants leading to an additional venous inflow to the liver apart from the usual dual blood supply (portal vein and hepatic artery). They tend to be associated with parenchymal pseudolesions (focal hyperenhancement on post-contrast imaging, focal fat infiltrati...
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Thoracic aortic dilatation (differential)

There are a number of causes and mimics of thoracic aortic dilatation. Differential diagnosis senile ectasia hypertension post-stenotic dilatation, e.g. bicuspid aortic valve thoracic aortic aneurysm atherosclerosis (usually descending thoracic aorta) collagen disorders Marfan syndrome ...
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Thoracic aortic stenosis (differential)

The differential for thoracic aortic stenosis includes: atherosclerosis aortitis (especially Takayasu arteritis) radiation coarctation pseudocoarctation Williams syndrome: supravalvular aortic stenosis congenital rubella syndrome: supravalvular aortic stenosis
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Thoracolith

Thoracoliths are rare, calcified pleural-based nodules that are almost always incidental findings. They are usually considered mobile, and more common on the left. Pathology The exact etiology is unknown and theories include 1,2: calcified fibrin body degenerated pleural lipoma old tubercul...
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Threatened miscarriage

Threatened miscarriage (or threatened abortion) is mainly a clinical term, used when a pregnant woman in first 20 weeks of gestation presents with spotting, mild abdominal pain and contractions, with a closed cervical os.  Epidemiology It occurs in 20-25% of pregnancies and is associated with ...
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Thyroid inflammatory conditions

A number of inflammatory conditions can affect the thyroid gland, each commonly described as a thyroiditis (plural: thyroiditides): acute thyroiditis acute suppurative thyroiditis (AST)  autoimmune thyroiditis​ subacute lymphocytic thyroiditis (a.k.a. silent thyroiditis or painless subacute ...
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Thyroid malignancies

Thyroid malignancies are most commonly primary thyroid cancers but can rarely be metastatic deposits. Pathology Classification Thyroid malignancies can be categorized into the following key subtypes: primary thyroid cancers ​papillary thyroid carcinoma: 60-80% of carcinomas follicular thyr...
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Tibiotalar slant

Tibiotalar slant is the superolateral inclination of the tibial plafond, and results in an ankle valgus deformity. There are a number of causes 1: trauma, i.e. distal tibial fractures osteomyelitis and/or septic arthritis juvenile idiopathic arthritis haemophilic arthropathy sickle cell dis...
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Tonsillar herniation

Tonsillar herniation is a type of cerebral herniation characterized by the inferior descent of the cerebellar tonsils below the foramen magnum. Clinically the presence of tonsillar herniation is often called coning. The terminology of caudally displaced tonsils is discussed in the article on ce...
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Tonsillitis

Tonsillitis refers to inflammation of any of the tonsils and is one of the most common head and neck infections in adolescents and young adults. Clinical presentation Patients may present with a variety of symptoms including painful throat (may be unilateral), dysphagia, fevers, tender cervica...
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Torticollis

Torticollis (wryneck) is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group.  Pathology Torticollis can be acute (<1 week) or chronic (...
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Total hip arthroplasty

Total hip arthroplasty (THA) or total hip replacement (THR) is an orthopedic procedure which involves the surgical excision of the femoral head and cartilage of the acetabulum and replacement of the joint with articulating femoral and acetabular components. It is a commonly performed procedure u...
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Toxoplasmosis vs lymphoma

Toxoplasmosis and lymphoma are frequently differential diagnoses in patients with HIV/AIDS, as these represent the most common brain lesions with mass effect in this population. As treatment is substantially different, distinguishing the two on imaging is important, particularly when the lesion ...
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Tracheal and endobronchial lesions

Primary tracheal and endobronchial lesions are generally rare and can be either malignant or benign. The majority of these lesions are malignant. Pathology Malignant primary malignant endobronchial lesions bronchogenic adenocarcinoma squamous cell carcinoma: commonest malignant lesion in tr...
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Tracheal buckling

Tracheal buckling is a normal finding in young infants when it is more flexible. There is typically deviation of the trachea anteriorly and to the right (up to 90°) and any other configuration (i.e. to the left or posteriorly) should raise the possibility of underlying pathology.  Practical poi...
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Tracheal masses

The differential for tracheal masses can be rather wide. For a single mass consider: metastasis  direct invasion from adjacent organ (lung, thyroid, esophagus and larynx) distant metastasis (e.g. melanoma, breast, renal and colon cancer)  primary neoplasms: squamous cell carcinoma: commone...
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Tracheal wall thickening

Tracheal wall thickening may have several causes. For diagnostic purposes, tracheal thickening may be categorized by length of airway involvement in order to narrow the differential diagnoses. Note that some etiologies may be associated with either focal or diffuse pattern of involvement. Focal...
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Traction bronchiectasis

Traction bronchiectasis refers to an etiological subtype of bronchiectasis where there is irreversible dilatation of bronchi and bronchioles within areas of pulmonary fibrosis or distorted lung parenchymal architecture. Pathology It can arise from a number of underlying causes which result in ...
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Transalar herniation

Transalar (transsphenoidal) herniation describes herniation of brain matter in and around the middle cranial fossa across the greater sphenoid wing and can be ascending or descending. Compression of structures against the sphenoid bone results in symptoms. Pathology Transalar herniation is not...
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Transient hepatic attenuation differences

Transient hepatic attenuation differences (THAD) lesions refer to areas of parenchymal enhancement visible during the hepatic artery phase on helical CT. They are thought to be a physiological phenomenon caused by the dual hepatic blood supply. Occasionally they may be associated with hepatic tu...
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Transtentorial herniation

Transtentorial herniation is a type of cerebral herniation. There are two types: descending transtentorial herniation, more frequently known as uncal herniation ascending transtentorial herniation, which is less common than uncal herniation
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Trapped lung

Trapped lung, also known as unexpandable/unexpanded lung, is a term used where there is non-expandable lung after fluid removal, often thoracentesis. It is similar to but not entirely synonymous with the term lung entrapment, which is a similar condition caused by active pleural disease rather t...
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Trauma in pregnancy

Trauma is a leading cause of mortality in pregnancy. Pregnancy increases the incidence and severity of abdominal trauma in females.  Epidemiology Trauma affects up to 7% of pregnancies, and the incidence of pregnancy in level 1 trauma patients is estimated to be ~2% 1.  Pathology Etiology 9...
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Traumatic spinal cord injury

Traumatic spinal cord injury can manifest as a wide variety of clinical syndromes resulting from damage to the spinal cord or its surrounding structures. It can result from minor injury if the spine is weakened from disease such as ankylosing spondylitis or if there is pre-existing spinal stenos...
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Triphalangeal thumb

Triphalangeal thumb is considered a form of pre-axial polydactyly. Epidemiology Triphalangeal thumbs have an incidence of 1 in 25,000 7.  Pathology A triphalangeal thumb, as the name implies, has three phalanges instead of the usual two. There is an autosomal dominant genetic transmission 8....
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Troponin

Troponin is a protein of key importance in the functioning of skeletal and cardiac muscle. It forms part of the contractile mechanism, and comprises three main subunits: troponin C, troponin I, and troponin T.  Troponin elevation Elevation of serum troponin can occur from a number of causes an...
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Tuberculosis (intracranial manifestations)

Tuberculosis of the central nervous system can result from either haematogenous spread from distant systemic infection (e.g. pulmonary tuberculosis) or direct extension from local infection (e.g. tuberculous otomastoiditis). Intracranial manifestations of tuberculosis are protean and can affect...
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Tubulinopathy

Tubulinopathy refers to a wide spectrum of cortical malformations that result from defects in genes encoding the tubulin protein that regulates neuronal migration during brain development. Clinical presentation Some series report a high prevalence of seizures during infancy which may the initi...
Article

Tumor ablation

Tumor ablation, or image-guided tumor ablation, is the direct application of chemical or energy-based (i.e. thermal and nonthermal) treatments to cause local tumor destruction. Techniques include: energy-based techniques thermal ablation radiofrequency ablation (RFA) microwave ablation (MWA)...
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Tumors of the chest wall (differentials)

Tumors of the chest wall are varied, some of which are found most often in this region. They can be divided into benign and malignant tumors and into those which arise in the ribcage and those of soft tissue density. Benign Benign tumors include 1,3,4: soft tissue hemangioma: common lymphan...
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Tumors of the male urethra

Tumors of the male urethra are uncommon. They can be categorized both on the grounds of histology and location. Histology squamous cell carcinoma of the urethra: 80% urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra) adenocarcinoma of the urethra: 5%...
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Tumors of the small intestine

The small intestine is rarely the site of malignant tumors, although it accounts for ~75% of the entire length of the GI tract and more than 90% of the mucosal surface. Approximately 40 different histologic tumor types have been described.  In this article, an overview will be given of the most...
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Tumors that metastasize to bone (mnemonic)

Tumors that metastasize to bone may be remembered using the mnemonic "lead kettle" spelled PBKTL (lead is Pb on the Periodic Table). PB-KTL Mnemonic P: prostate B: breast K: kidney T: thyroid L: lung For females, breast and lung are the most common primary sites; nearly 80% of cancers th...
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Twin pregnancy

Twin pregnancies are the most common multifetal pregnancies.  Epidemiology Multifetal pregnancies account for ~ 1% of all pregnancies but are seen in much higher numbers in populations where in vitro fertilisation (IVF) is a common practice, most of which are twin pregnancies. Classification ...
Article

Ulnar variance

Ulnar variance (also known as Hulten variance) refers to the relative lengths of the distal articular surfaces of the radius and ulna.  Ulnar variance may be: neutral (both the ulnar and radial articular surfaces at the same level) positive (ulna projects more distally) negative (ulna projec...
Article

Ultrasound appearances of liver metastases

Ultrasound appearance of liver metastases can have bewildering variation, and the presence of hepatic steatosis can affect the sonographic appearance of liver lesions. Radiographic features Ultrasound Patterns do exist between ultrasound appearance of the liver metastases and the likely prima...
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Umbilical cord cyst

Umbilical cord cysts can refer to any cystic lesion associated with the umbilical cord. They can be single (commoner) or multiple. Epidemiology They may be seen in ~3% of pregnancies in the first trimester 8. Pathology Umbilical cord cysts can represent either true or false cysts: true cyst...
Article

Unilateral axillary lymphadenopathy (differential)

Unilateral axillary lymphadenopathy while being more concerning than bilateral axillary lymphadenopathy can still arise from a variety of benign, as well as malignant, causes. Benign mastitis other regional infective causes tuberculosis ipsilateral arm infection, e.g. cellulitis silicone i...
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Unilateral facet dislocation

Unilateral facet dislocation is a relatively stable type of facet dislocation. Pathology Mechanism Flexion/distraction associated with rotation. The inferior articular facet of vertebral above moves over the superior facet of the vertebral below and becomes locked. It usually affects C4-C5 or...

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