Items tagged “refs”

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...

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 It is no longer in widespread use, having been gradually superseded by the 6-tier BI-RADS classification system first published in 1992.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 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: in...

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 pneumoni...

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 ...

Ameloblastic fibromas appear as unilocular lucent mandibular lesions, most frequently in the posterior mandible, and are usually associated with impacted teeth, centered on the unerupted crown. They, therefore, appear very similar to unilocular ameloblastomas. They are composed of enamel and emb...

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 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...

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...

Arteriovenous malformations (AVMs) are characterized 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 ...

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...

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...

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 deoxyhemoglobin of hemorrhage hemosi...

The causes of basal ganglia T2 hyperintensity can be remembered using the mnemonic LINT: lymphoma ischemia hypoxic-ischemic encephalopathy venous infarction (internal cerebral vein thrombosis) neurodegenerative  autoimmune encephalitis (e.g. anti-D2 dopamine antibody...

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,...

A bifid or forked or bifurcated rib is a congenital skeletal abnormality of the rib cage with the cleaved sternal end into two. They are thought to occur in ~0.2% of the population and there may be a female as well as right-sided predilection 2. Epidemiology Associations Bifid ribs can be see...