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.

1,138 results found

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...

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


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. 

Ventriculoperitoneal shunt

Ventriculoperitoneal (VP) shunts are a device used in the treatment of non-obstructive hydrocephalus. As the name suggests, a catheter is placed in the ventricle, and another catheter travels under the skin to opens into the peritoneal cavity, both the catheters being connected to each other th...

Vertebral body mass

The differential diagnosis for a vertebral body mass is broad and may range from a completely benign, sclerotic enostosis (bone island) to a malignant primary bone tumour. Classification Broadly, these lesions can be separated into: non-neoplastic lesions primary bone tumours secondary meta...

Vertebral scalloping

Vertebral scalloping is a concavity to the posterior (or less commonly anterior) aspect of the vertebral body when viewed in a lateral projection. A small amount of concavity is normal, as is concavity of the anterior vertebral body (see vertebral body squaring). Posterior scalloping Causes of...

Vertebra plana

Vertebra plana (a.k.a. pancake / silver dollar / coin-on-edge vertebra) is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture. Plural is vertebrae planae. It can occur in a variety of settings, incl...

Vertical-banded gastroplasty

Vertical-banded gastroplasty (VBG) is an older, purely restrictive procedure used to treat morbid obesity. Procedure It involves creating a small gastric pouch, based on the lesser curvature of the stomach (which is thicker and less resistant to stretching than the greater curvature), by using...

Very bizarre generalised lesions of bone (differential)

Very bizarre generalised lesions of bone tend to make you exclaim "Oh my! What is going here?"  Although there are numerous potential causes, in this situation it is worth thinking of a number of entities: skeletal dysplasias and metabolic diseases Paget disease fibrous dysplasia phakomatose...

Vestibular line of Lapayowker

The vestibular line of Lapayowker refers to a vertical line passing down the most lateral aspect of vestibular apparatus. The petrous part of internal carotid artery lies medial to this line but lies lateral to it in the case of an aberrant internal carotid artery which is the characteristic ang...

Viral encephalitides

Viral encephalitides are the result of the brain parenchyma infection by a number of different viruses, many of which have similar presentations and imaging features. Specific diagnosis often requires PCR.  For viral infection of the meninges, please refer to the general article on viral mening...

Visceral artery aneurysms

Visceral artery aneurysms (VAA) are abnormal focal dilatations of arteries supplying an organ in the abdomen. VAAs include both true and pseudoaneurysms. With different clinical manifestations and a more characteristic pathology, the renal artery aneurysms are discussed separately.  Epidemiolo...

Vulval neoplasms

Vulval neoplasms are rare and mostly seen in an elderly female patients. Squamous cell carcinoma is most common malignancy of the vulva which only 30% of them are associated with oncogenic HPV viruses. Pathology Squamous neoplastic lesions  Premalignant  classic vulvar intraepithelial neopla...

Wackenheims line

Wackenheims line (also known as the clivus canal line or basilar line) is formed by drawing a line along the clivus and extending it inferiorly to the upper cervical canal. Normally the tip of the dens is ventral and tangential to this line. In basilar invagination odontoid process transects th...

Wartenberg syndrome

Wartenberg syndrome also known as cheiralgia paresthetica is due to compression of superficial branch of the radial nerve in the distal forearm. It can be secondary to tight watch band or handcuffs, compression from distal radius fracture or idiopathic.  Clinical presentation Patients present ...

Well-defined breast cancers (differential)

Certain well-defined breast cancers tend lack the characteristic spiculation and can give false reassurance of more benign entities on both ultrasound and mammography. These include: certain high grade invasive ductal carcinomas: not enough time for a desmoplastic reaction to form spiculation ...

White coat hypertension

White coat hypertension (abbreviated alternatively as WCH or WCHT), not to be confused with the white coat effect (WCE), is commonly defined as typical in-clinic blood pressure (BP) measurements of 140/90 mm Hg or more in the presence of multiple daytime out-of-clinic home or ambulatory BP readi...

White matter changes in HIV

White matter changes in HIV have overlapping appearances and varied in aetiology. These can be divided into: primary effects of HIV opportunistic infection neoplasms vascular disease metabolic and nutritional disorders Primary effects of HIV HIV encephalitis Opportunistic infection cyto...

Widening of interpedicular distance

The interpedicular (IP) distance which is the distance measured between the pedicles on frontal / coronal imaging can be widened in a number of situations. Pathology Causes include diastematomyelia syringomyelia conditions that can cause dural ectasia (can potentially cause widening) Marfa...

Widening of the presacral space (differential)

Widening of the presacral space is one of the diagnostic indicators of the diseases involving pelvic pathology and rectal involvement. It is ideally measured on barium studies at the level of S3/4 disc level on lateral radiographs and the normal value of the presacral space is <15 mm in adults.​...

Winking owl sign (spine)

The (absent) pedicle sign, also called the winking owl sign, occurs on plain film when a pedicle is absent. The term, winking owl sign, where the missing pedicle corresponds to the closed eye, the contralateral pedicle to the other open eye, and the spinous process to the beak of the animal on ...

X-ray artifacts

Artifacts can present in a variety of ways including abnormal shadow noted on a radiograph or degraded image quality and have been produced by artificial means from hardware failure, operator error and software (post-processing) artifacts.  There are common and distinct artifacts for film, comp...

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