Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,135 results found
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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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Substernal goitre

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

Superficial siderosis is a rare condition which results from the deposition of haemosiderin along the leptomeninges, with eventual neurological dysfunction. On imaging, it is classically characterised on MRI as a rim of low signal coating the surface of the brain or spinal cord, particularly no...
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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 or arising from the lumbar vertebra. In extremely rare situations, there can be sacral, coccygeal, intrathoracic, or aberrant lumbar ribs 3. Associations Turner syndrome cleidocranial dysplasia Aarskog syndrome trisomy 8 syndrome inc...
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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. This appearance can result from a range of aetiological factors: diffuse metastatic disease prostatic carcinoma breast cancer transitional cell carcinoma (...
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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 helps, especially when under the pressure of the exam situation. Differentials from the sections of the sieve can be considered in turn, helping to extend the list in a structured way. They include: 5I 3-Scotland VITAMIN VITAMIN C...
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Suspicious breast calcifications

Suspicious breast calcifications are calcifications within the breast that are not benign. These calcification need further work up and biopsy. These can be divided as suspicious calcification of intermediate concern  suspicious calcification raising high probability of malignancy
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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-t...
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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 periosteal reaction of the newborn (Caffey disease), most common cause before 6 months old juvenile idiopathic arthritis​ pachydermoperiostosi...
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Synchronous primary lung carcinoma

Synchronous primary lung carcinoma (SPLC) is a term given to the occurrence of two or more primary lung carcinomas within different portions of the lung in the same time period. They are thought to the carry the same pathophysiological mechanism as metachronous lung carcinoma (i.e. two or more ...
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Syndactyly

Syndactyly 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 2500 to 5000 live births 6,8. The...
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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 Radiographic features Appearance on plain radiographs comprises v...
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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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Tauopathies

Tauopathies are a heterogeneous group of neurodegenerative diseases characterised 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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Tear drop sign of the superior mesenteric vein

Tear drop sign of the superior mesenteric vein (SMV) is one of the important signs in the staging of pancreatic adenocarcinoma. Its importance lies in its diagnosis as well as prognostic significance. This sign is used in assessing the resectability of pancreatic cancer. Radiographic features ...
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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 tumours sinus pol...
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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 acoustic schwannoma meningioma glioma neuroma of trigeminal and facial nerve chordoma glomus jugulare tumour epidermoid of...
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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 pneumoperitoneum

Tension pneumoperitoneum is a special and rare type of pneumoperitoneum, in which the free intra-abdominal peritoneal gas is under pressure. The mechanism is thought to be a ball-valve effect allowing the one-way accumulation of gas. This results in: elevation and splinting of the diaphragm red...
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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 rapid recognition and treatment is required if a cardiorespiratory arrest is to be a...
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Terminal ileitis (differential)

The differential diagnosis for a terminal ileitis is quite extensive, and includes: inflammatory bowel disease Crohn's disease (most common) backwash ileitis due to ulcerative colitis infectious colitis Yersinia spp.  Yersinia enterocolitica Yersinia pseduotuberculosis Salmonella spp. C...
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Terminal tuft masses

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 giant cell tumour of the tendon sheath: occur laterally subu...
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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. 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 tumour. Over ...
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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. Testicular rupture and testicular ischaemia/infarct are two severe complications which need to be ruled out. Other injuries that can occur include 1: testicular frac...
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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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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 aetiology is unknown and theories include 1,2: calcified fibrin body degenerated pleural lipoma old tubercu...
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Thorotrast

Thorotrast is a radioactive radiographic contrast agent containing thorium dioxide first produced in Germany in 1928 and was in use until the 1950s. It was used primarily for cerebral angiography, and 90% of the estimated 50,000-100,000 patients who received it were studied for this purpose.  T...
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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, which are commonly described as thyroiditides: acute thyroiditis acute suppurative thyroiditis (AST)  autoimmune thyroiditis​ subacute lymphocytic thyroiditis: silent thyroiditis or painless subacute thyroiditis  postpartum t...
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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 categorised into the following key subtypes: primary thyroid cancers ​papillary thyroid carcinoma: 60-80% of carcinomas follicular thyr...
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Thyrotoxicosis

Thyrotoxicosis is a hypermetabolic clinical syndrome caused by a pathological excess of circulating free T4 (thyroxine) and/or free T3 (triiodothyronine). Terminology Although commonly done, thyrotoxicosis should not be confused nor synonymized with hyperthyroidism, the latter of which is a gr...
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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 characterised by the inferior descent of the cerebellar tonsils below the foramen magnum. Pathology It is a secondary sign of significant intra-cranial mass effect. Any intra-axial or extra-axial lesion (e.g. tumour, haemorrhage, stroke, ab...
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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 paediatric 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 orthopaedic 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 ...
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Toxoplasmosis

Toxoplasmosis is a common worldwide parasitic disease caused by the protozoan Toxoplasma gondii. It is usually an asymptomatic infection, but it is related with several sequelae when acquired in-utero or related with cerebral abscesses due to its reactivation in immunocompromised patients (e.g. ...
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Toxoplasmosis vs lymphoma

It is a relatively common occurrence for radiologists to be asked to distinguish between cerebral toxoplasmosis and primary CNS lymphoma (PCNSL) in patients with HIV/AIDS. Treatment is clearly different and thus accurate interpretation of CT and MRI is essential. In many instances appearances a...
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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 calcification

Tracheal calcification is a benign radiological finding of the middle aged and elderly and is usually of no clinical significance. The appearance is often striking as individual tracheal rings become radio-opaque and stand out from the soft tissue mediastinum.  Pathology Associations long-te...
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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, thryoid,esophagus) distant metastsis ( such as melanoma)  primary neoplasms: squamous cell carcinoma: commonest primary tracheal malignancy 2 ~50 % a...
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Tracheomalacia

Tracheomalacia, or sometimes described as tracheobronchomalacia, is a common incidental finding on imaging of the chest of older patients and manifests as an increase in tracheal diameter as well as a tendency to collapse on expiration. Generally, more than 70% of collapse of the trachea during ...
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Traction bronchiectasis

Traction bronchiectasis refers to an aetiological sub type 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 i...
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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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Transependymal oedema

Transependymal oedema, also known as interstitial cerebral oedema, is a type of cerebral oedema that occurs with increased pressure within the cerebral ventricles. FLAIR MRI sequence is the most sensitive MRI sequence to detect this type of oedema. Pathology The ventricular ependymal lining is...
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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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Transient lesion of the splenium

Transient lesions of the splenium of the corpus callosum, also known as mild encephalitis/encephalopathy with a reversible isolated SCC lesion (MERS), are occasionally encountered on MRI studies and may be due to a number of underlying aetiologies. Clinical presentation Unlike other causes of ...
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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 but caused by active pleural disease rath...
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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 Aetiology ...
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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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Triangle of Guillain and Mollaret

The triangle of Guillain and Mollaret, also known as dentatorubro-olivary pathway, has three corners 1: red nucleus inferior olivary nucleus contralateral dentate nucleus Connecting fibres are only identified between the red nucleus and inferior olivary nucleus (central tegmental tract) and ...
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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 elevation

Troponin elevation can occur from a number causes although there is no imaging involved, it is useful for the radiologist to have a basic understanding of their causes (especially when interpreting imaging findings associated with troponin elevation). The cardiac troponin complex consists of thr...
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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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Tuberculous adrenalitis

Tuberculous adrenalitis is the result of adrenal mycobacterium tuberculosis (TB) infection. Its incidence has decreased in the western world with the declining incidence of tuberculosis. Pathology As the tuberculous infection causes destruction of the adrenal cortex, primary adrenal insufficie...
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Tumour markers

Tumour markers are a group of molecules in serum that are elevated in various malignancies and are often used to monitor treatment response as well as alert for potential progressive disease when in remission. Commonly used markers include: AFP beta-hCG CA 19-9 CA-125 CEA chromogranin A P...
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Tumours of the chest wall (differentials)

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

Tumours of the male urethra are uncommon. They can be categorised 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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Tumours of the small intestine

The small intestine is rarely the site of malignant tumours, 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 tumour types have been described.  In this article, an overview will be given of the mo...
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Tumours that metastasise to bone (mnemonic)

Tumours that metastasise 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 t...
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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...
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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...
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Ultrasound appearances of liver metastases

Ultrasound appearance of liver metastases can have bewildering variation. Patterns do exist between ultrasound appearance of the liver metastases and the likely primary, which is sometimes helpful in directing a search for an unknown primary, as well as helping distinguish between benign lesion...
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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...
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Unilateral axillary lymphadenopathy (differential)

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

Unilateral pulmonary oedema

Unilateral pulmonary oedema represents only 2% of cardiogenic pulmonary oedema with predilection for the right upper lobe and is strongly associated with severe mitral regurgitation 1, 2. It is hypothesised that the regurgitation jet is directed towards the right superior pulmonary vein thus pre...
Article

Upper gastrointestinal bleeding (differential)

An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz. Pathology Causes peptic ulcer gastritis oesophagitis duodenitis Mallory-Weiss tear varices tumour vascular abnormality vascular ectasia angiodysplasia Dieulafoy lesion vascular malformati...
Article

Upper lobe bronchiectasis

Distribution of bronchiectasis can help in narrowing the differential diagnosis. Upper lobe bronchiectasis is typically seen in: cystic fibrosis tuberculosis Rarely it may be seen with non tuberculous mycobacterial infection (e.g. MAC infection 2) When in mid-upper lobes also consid...
Article

Urethral stricture

Urethral strictures are relatively common, and typically occur either in the setting of trauma or infection. Epidemiology The demographics of the affected population is dictated by the aetiology, but in general it is safe to say that adult males make up the vast majority of cases. Clinical pr...
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Urinary bladder diverticula (causes)

There are numerous causes of urinary bladder diverticula:  Primary (congenital or idiopathic) Hutch diverticulum (in paraureteral region) Secondary Bladder outlet obstruction bladder neck stenosis neurogenic bladder posterior urethral valve prostatic enlargement (hypertrophy; carcinoma) ...
Article

Urinary bladder diverticulum

Bladder diverticulum are outpouchings from the bladder wall, whereby mucosa herniates through the bladder wall. They may be solitary or multiple in nature and can vary considerably in size. Epidemiology There are two peaks - one at 10 years and the other at 60-70 years 2. Pathology Diverticu...
Article

Urinary bladder wall or lumen calcification (differential)

Causes of urinary bladder wall or lumen calcification include: Common bladder calculus schistosomiasis of the urinary tract tuberculosis Uncommon neuroblastoma; pheochromocytoma radiation reaction alkaptonuria (ochronosis) amyloidosis calculus in a urachal cyst or in a bladder divertic...
Article

Urinary diversion

Urinary diversion is created after the removal of the urinary bladder (radical cystectomy or cystoprostatectomy, usually done to treat invasive bladder cancer). There are three main varieties: neobladder formed from a segment of ileum (i.e. ileal conduit, also known as a "Bricker conduit") th...
Article

Uterine enlargement (differential)

Uterine enlargement can occur in a number of situations from both diffuse and focal processes. These include:  gestation related events normal intrauterine pregnancy molar pregnancy - gestational trophoblastic disease  postpartum uterus - still larger than usual hormonal causes exogenous h...
Article

Valgus vs varus

The terms valgus and varus refer to angulation (or bowing) within the shaft of a bone or at a joint. It is determined by the distal part being more medial or lateral than it should be. Whenever the distal part is more lateral, it is called valgus. Whenever the distal part is more medial, it is ...
Article

Valsalva manoeuvre

The Valsalva manoeuvre is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling. It is commonly u...
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Vascular pedicle

Vascular pedicle is bordered on the right by venous structures (right brachiocephalic vein above and superior vena cava) and on the left by an arterial structure (the left subclavian artery origin). The azygos vein (black oval) is seen en face above the right main bronchus. The vascular pedicle...
Article

Vascular rings and slings

Vascular rings and slings refer to the congenital vascular encirclement of the oesophagus and/or trachea by anomalous/aberrant vessels.  Epidemiology Vascular rings are rare, occurring in <1% of patients 1. No gender or ethnic predispositions have been identified 3.  Clinical presentation Ma...
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Venous thromboembolism

Venous thromboembolism covers a wide spectrum of diseases. Individual conditions and complicating condition include: deep vein thrombosis (DVT) pulmonary embolism (PE) dural venous sinus thrombosis Lemierre's syndrome tumour thrombus
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Ventriculomegaly

Ventriculomegaly is defined as enlargement of the ventricles. Simply, there are two causes: hydrocephalus communicating non-communicating parenchymal atrophy Refer to the article on hydrocephalus vs. atrophy for more details on how to differentiate both entities. 

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