Items tagged “refs”

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 syndrome tumor thrombus

The 5-tier ACR system was a previously used system for classification of radiologic breast findings, proposed by the American College of Radiology (ACR). It is no longer in widespread use, having been gradually superseded by the 6-tier BI-RADS classification system first published in 1992. Inter...

The 5th metacarpal pit refers to the normal exaggeration of the pit-like depression in the head of fifth metacarpal.  It should not be mistaken for a fracture (old or new) or an erosion.

AIDS cholangiopathy refers to an acalculous, secondary opportunistic cholangitis that occurs in AIDS patients as a result of immunosuppression.  Pathology Characterized by multiple irregular strictures essentially indistinguishable from primary sclerosing cholangitis (PSC). There are four path...

Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are one of the commonest of the aortic arch anomalies.  Epidemiology The estimated incidence is 0.5-2%. Clinical presentation They are often asymptomatic, but around 10% of people may complain of tracheo-esophageal sym...

The accessory middle cerebral artery is a variant of the middle cerebral artery (MCA) that arises from the anterior cerebral artery (ACA). It is different from a duplicated middle cerebral artery, in which the duplicated vessel originates also from the distal end of the internal carotid artery (...

Acute bilateral airspace opacification is a subset of the larger differential diagnosis for airspace opacification. An exhaustive list of all possible causes of acute bilateral airspace opacities is long, but a useful way to consider the huge list is via the material within the airways: infecti...

Acute unilateral airspace opacification is a subset of the differential diagnosis for airspace opacification.   Differential diagnosis The exhaustive list of all possible causes would be huge, but a useful framework includes: pus, i.e. infection bacterial pneumonia fungal pneumonia viral p...

Acute airspace opacification with lymphadenopathy is a subset of the differential diagnosis for generalized airspace opacification and includes: post-obstructive causes (usually chronic, but 'new' changes can occur) primary lung cancer pulmonary metastases lymphoma/leukemia infection prim...

Adenomatoid odontogenic tumors are rare and differ from most other dentition related lesions in that they more frequently occur in the maxilla. Epidemiology They are also seen more frequently in females, most frequently in the second decade of life. Radiographic features They present as an e...

Agger nasi air cells are the most anterior ethmoidal air cells lying anterolateral and inferior to the frontal recess and anterior and above the attachment of the middle turbinate. They are located within the lacrimal bone and therefore have as lateral relations the orbit, the lacrimal sac and t...

Air bronchogram refers to the phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white). It is almost always caused by a pathologic airspace/alveolar process, in which something other than air fills the alveoli. Air bronchograms will not ...

The spinnaker sign (also known as the angel wing sign) is a sign of pneumomediastinum seen on neonatal chest radiographs. It refers to the thymus being outlined by air with each lobe displaced laterally and appearing like spinnaker sails. This is distinct from the sail sign appearance of the nor...

Musculoskeletal angiosarcomas, (along with hemangiopericytomas and hemangioendotheliomas) are tumors that arise from vascular structures. They are typically difficult to distinguish from one another on imaging alone. Angiosarcomas, are the most aggressive of the three, frequently having metasta...

The anterior capsular insertion, unlike the posterior aspect of the shoulder joint capsule which has a constant scapular attachment along the margins of the glenoid labrum, inserts a variable distance from the labrum. The capsular insertions are classified as follows: type I: at or very near t...

The aorta, the great artery, is the largest artery of the human body and carries oxygenated blood ejected from the left ventricle to the systemic circulation. It is divided into: thoracic aorta ascending aorta aortic arch descending aorta abdominal aorta It has branches from each section a...

Aphthoid ulcers are shallow ulcers of the gastrointestinal mucosa. Pathology Etiology infective inflammatory conditions Yersinia enterocolitis amoebic enterocolitis cytomegalovirus enterocolitis noninfective inflammatory conditions Crohn disease idiopathic granulomatous gastritis vascu...

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 Mönckeberg medial calcific sclerosis: muscular arteries arter...

Arteriovenous malformations (AVMs) are characterized by an abnormal leash of vessels allowing for arteriovenous shunting. They can occur anywhere in the body but have a predilection towards the head and neck.  There is a direct arteriovenous communication with no intervening capillary bed. They ...

An azygos lobe is created when a laterally displaced azygos vein creates a deep pleural fissure into the apical segment of the right upper lobe during embryological development. It is a normal anatomic variant of the right upper lobe due to invagination of the azygos vein and pleura during devel...