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.

1,794 results found
Article

Vitamin B6

Vitamin B6 is a group water soluble vitamins that are deratives of pyridine, namely pyridoxine, pyridoxal and pyridoxamine. All three form part of the coenzyme pyridoxal 5'-phosphate (PLP) which is involved many cellular reaction including the synthesis of several amino acids and the metabolism ...
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Vitamin B7

Vitamin B7 (biotin) is a water soluble vitamin that is a coenzyme for many reactions, including gluconeogenesis and the synthesis of fatty acids and amino acids. Biotin deficiency is caused by dietary insufficiency, pharmacological interactions and, possibly, increased biotinolysis in smokers a...
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Vitamin B9

Vitamin B9 (folate or folic acid) is a water soluble vitamin that is vital for the synthesis of several amino acids, the purines adenosine and guanine and the pyrimidine thymine (three of the four nucleotide bases and hence critical for the synthesis of nucleic acids.) The antimicrobial group s...
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Vitamin C

Vitamin C (ascorbic acid) is a water soluble vitamin that is a coenzyme for the formation of the structure protein collagen, particularly creating cross-linking of collagen fibres which greatly increases its tensile strength. It also acts as an antioxidant. Related pathology Pathological manif...
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Vitamin D

Vitamin D is used to describe a group of five fat-soluble secosteroid vitamins required for the homeostasis of serum calcium and phosphorus. Vitamin D is a prohormone that exists in two forms in humans (D2 and D3). Cholecalciferol (D3) acts by regulating calcium and phosphorus intestinal absorp...
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Vitamin E

Vitamin E (the tocopherols) are a group of fat-soluble vitamins that act as an antioxidant. Hypovitaminosis E is rarely seen outside premature infants. Hypervitaminosis E is extremely rare as vitamin E is the least toxic of all the vitamins.
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Vitamin K

Vitamin K (phylloquinone (K1) and menaquinone (K2)) are a group of fat-soluble vitamins essential for normal blood-clotting function. Menaquinone is synthesised by normal flora in the intestine although the amount produced in vivo in the human gut is likely negligible. Vitamin K serves as a coen...
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Vitamins

Vitamins are a group of organic compounds used in biochemical pathways. Many are components of coenzymes in particular metabolic reactions. Vitamins are generally not synthesised by the human body and hence must be acquired through the diet. In radiology, there are some imaging manifestations o...
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Vocal cord paralysis

Vocal cord paralysis/palsy (VCP) can cause laryngeal dysfunction ranging from slight hoarseness to life-threatening airway obstruction. Pathology Left vocal cord paralysis is twice as common than right vocal cord paralysis, and unilateral vocal cord paralysis much less common than bilateral vo...
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Voltage gated potassium channel (VGKC) antibody encephalitis

Voltage gated potassium channel (VGKC) antibody encephalitis is an autoimmune encephalitis with antibodies against the voltage gated potassium channel. It is one of the most common forms of autoimmune limbic encephalitis in the absence of primary extra-CNS tumours. Autoimmune VGKC encephalitis c...
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Wagstaffe-Le Forte fracture

A Wagstaffe-Le Forte fracture refers to an avulsion fracture of the medial aspect of the distal fibula due to avulsion of the anterior talofibular ligament attachment. See also lower extremity fractures
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Waldenström's macroglobulinaemia

Waldenström's macroglobulinaemia (WM), (previously also known as lymphoplasmacytic lymphoma (LPL)), is a type of B-cell lymphoma. It is a rare condition, accounting for only 1% of all lymphoproliferative disorders.  Recent publications classify Waldenström's macroglobulinaemia as an lymphoplasm...
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Walled-off pancreatic necrosis

Walled-off pancreatic necrosis (WOPN) is a late complication of acute pancreatitis, although it can occur in chronic pancreatitis or as a result of pancreatic trauma. Differentiation of WOPN from pancreatic pseudocyst is essential because management differs. WOPN may need aggressive treatment to...
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Wallerian degeneration

Wallerian degeneration (WaD) is the process of antegrade degeneration of the axons and their accompanying myelin sheaths following proximal axonal or neuronal cell body lesions. It may result following neuronal loss due to cerebral infarction, trauma, necrosis, focal demyelination or haemorrhage...
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Warthin tumour

Warthin tumours (or papillary cystadenoma lymphomatosum) are benign, sharply demarcated tumours of the salivary gland. They are of lymphoid origin and most commonly arise from parotid gland tail. They may be bilateral or multifocal in up to 20% of cases and are the most common neoplastic cause o...
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Watershed cerebral infarction

Watershed cerebral infarctions, also known as border zone infarcts, occur at the border between cerebral vascular territories where the tissue is furthest from arterial supply and thus most vulnerable to reductions in perfusion.  Epidemiology Watershed cerebral infarction account for 5-10% of ...
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Whipple disease

Whipple disease is a rare infectious multisystem disorder caused by the actinobacteria Tropheryma whipplei. Epidemiology The incidence of Whipple disease is not truly known, one Swiss study estimated it at approximately 1 per 1.5 million per year 7. The peak age for presentation is in the fif...
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Widening of diploic space

Widening of diploic space refers to diffuse, most commonly bilateral, calvarium widening secondary to extramedullary hematopoiesis within the skull. Causes Most commonly caused by systemic underlying pathologies such as: chronic haemolytic disorders: may be associated with vertical striations...
Article

Wilms tumour

Wilms tumour, also known as nephroblastoma, is a malignant paediatric renal tumour. Epidemiology Wilms tumours are the most common paediatic renal mass, accounting for over 85% of cases 1,8 and accounts for 6% of all childhood cancers 2. It typically occurs in early childhood (1-11 years) with...
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Wilson disease (CNS manifestations)

Wilson disease, also known as hepatolenticular degeneration, is a multisystem disease due to abnormal accumulation of copper. It is characterised by early onset liver cirrhosis with CNS findings most frequently affecting the basal ganglia and midbrain. This article aims to discuss the central n...
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Wilson disease (musculoskeletal manifestations)

Wilson disease, also known as hepatolenticular degeneration, is a multisystem disease, which rarely has musculoskeletal manifestations when there is accumulation of copper in the articular cartilage.  Radiographic features Plain radiographs Reported manifestations include 1,2,3 premature ost...
Article

Windswept pelvis

Wind-swept pelvis fracture is a combination a unilateral AP compression (open book) injury with a contralateral lateral compression injury.  It occurs when the internal rotation of one iliac wing causes a unilateral sacral compression fracture, while the same forces cause external rotation of t...
Article

Wolff-Chaikoff effect

Wolff-Chaikoff effect is an autoregulatory phenomenon, whereby a large amount of ingested iodine acutely inhibits thyroid hormone synthesis within the follicular cells, irrespective of the serum level of thyroid-stimulating hormone (TSH) 1.  Pathology The Wolff-Chaikoff effect is thought to be...
Article

Wrisberg rip

Wrisberg rips are longitudinal vertical meniscal tears. They occur at the at the junction of the ligament of Wrisberg and the posterior horn of the lateral meniscus, and are commonly associated with anterior cruciate ligament tears 1. 
Article

Xanthogranulomatous cholecystitis

Xanthogranulomatous cholecystitis is an uncommon inflammatory disease of the gallbladder which may be difficult to differentiate from malignancy, both on imaging and pathologically. It is characterised by presence of multiple intramural nodules. Epidemiology It is seen predominantly in female ...
Article

Xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis and represents a chronic granulomatous disease resulting in a non-functioning kidney. Radiographic features are usually specific. Epidemiology Xanthogranulomatous pyelonephritis is seen essentially in all age gro...
Article

Z deformity

The Z deformity is one of the musculoskeletal manifestation of rheumatoid arthritis in hand: radial deviation at the wrist ulnar deviation of the digits, and often palmar subluxation of the proximal phalanges

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