Items tagged “refs”
2,977 results
Article
Venous thromboembolism
Venous thromboembolism covers a wide spectrum of diseases. Individual conditions and complicating condition include:
head and neck
cerebral vein thrombosis
dural venous sinus thrombosis
cavernous sinus thrombosis
deep cerebral vein thrombosis
cortical vein thrombosis
superior ophthalmic v...
Article
5-tier ACR system of radiologic breast findings (historical)
The 5-tier ACR system was a previously used system for the classification of radiologic breast findings, proposed by the American College of Radiology (ACR) ref. It is no longer in use having been superseded by the 6-tier BI-RADS classification system first published in 1992 1.
Classification
...
Article
Accessory middle cerebral artery
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 (...
Article
Acute bilateral airspace opacification (differential)
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...
Article
Acute unilateral airspace opacification (differential)
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. pulmonary infection)
bacterial pneumonia
fungal pneumon...
Article
Acute airspace opacification with lymphadenopathy (differential)
Acute airspace opacification with lymphadenopathy is a subset of the differential diagnosis for generalised airspace opacification and includes:
post-obstructive causes (usually chronic, but 'new' changes can occur)
primary lung cancer
pulmonary metastases
lymphoma/leukaemia
infection
pri...
Article
Adenomatoid odontogenic tumour
Adenomatoid odontogenic tumours 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 ...
Article
Agger nasi cells
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...
Article
Air bronchogram
An air bronchogram occurs when endobronchial air is visible against a background of increased lung opacity. Expulsion of gas from the parenchyma is partial or complete and can be due to atelectasis and/or replacement by fluid, inflammatory cells, blood, tumour or interstitial thickening. The per...
Article
Ameloblastic fibroma
Ameloblastic fibromas appear as unilocular lucent mandibular lesions, most frequently in the posterior mandible, and are usually associated with impacted teeth, centred on the unerupted crown. They, therefore, appear very similar to unilocular ameloblastomas. They are composed of enamel and embr...
Article
Musculoskeletal angiosarcoma
Musculoskeletal angiosarcomas, (along with haemangiopericytomas and haemangioendotheliomas) are tumours 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 meta...
Article
Aorta
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...
Article
Arteriosclerosis
Arteriosclerosis is defined by thickening and loss of elasticity of the arterial walls.
There are three patterns of arteriosclerosis:
atherosclerosis: large and medium-sized arteries
Mönckeberg medial calcific sclerosis: muscular arteries
arteriolosclerosis: small arteries and arterioles
At...
Article
Arteriovenous malformation
Arteriovenous malformations (AVMs) are characterised by an abnormal leash of vessels allowing for arteriovenous shunting. They can occur anywhere in the body but are most common in the brain 1. There is direct arteriovenous communication with no intervening capillary bed. They can be congenital ...
Article
BOLD imaging
Blood oxygenation level dependent (BOLD) imaging is the standard technique used to generate images in functional MRI (fMRI) studies, and relies on regional differences in cerebral blood flow to delineate regional activity.
Blood flow in the brain is highly locally controlled in response to oxy...
Article
Bamboo spine (ankylosing spondylitis)
Bamboo spine is a pathognomonic radiographic feature seen in ankylosing spondylitis that occurs as a result of vertebral body fusion by marginal syndesmophytes. It is often accompanied by fusion of the posterior vertebral elements as well.
A bamboo spine typically involves the thoracolumbar and...
Article
Basal ganglia T2 hypointensity
Basal ganglia T2 hypointensities can be caused by any of the following and is commonly remembered using the mnemonic ChOMP.
childhood hypoxia
old age
multiple sclerosis
Parkinson disease: more in globus pallidus
Parkinson-plus syndrome: more in putamen
deoxyhaemoglobin of haemorrhage
haem...
Article
Basal ganglia T2 hyperintensity
The causes of basal ganglia T2 hyperintensity can be remembered using the mnemonic LINT:
lymphoma
ischaemia
hypoxic-ischaemic encephalopathy
venous infarction (internal cerebral vein thrombosis)
neurodegenerative
autoimmune encephalitis (e.g. anti-D2 dopamine receptor encephalitis, anti-C...
Article
Bezoar
Bezoars are accumulations of indigestible contents within the gastrointestinal tract.
Epidemiology
Associations
previous gastric surgery 2
psychiatric illness
Pathology
There are several types depending on the predominant components 2:
trichobezoar: a bezoar formed from hair, this has al...
Article
Bifid rib
A bifid or bifurcated rib is a congenital skeletal abnormality where the affected rib has a forked sternal end. They are thought to occur in ~0.2% of the population and there may be a female and right-sided predilection 2.
Epidemiology
Associations
Gorlin (nevoid basal cell carcinoma) syndrom...