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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
1,380 results found
Article
Abdominal and pelvic anatomy
Abdominal and pelvic anatomy encompasses the anatomy of all structures of the abdominal and pelvic cavities.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.
Article
Abdominal aorta
The abdominal aorta (plural: aortas or aortae 4) is the main blood vessel in the abdominal cavity that transmits oxygenated blood from the thoracic cavity to the organs within the abdomen and to the lower limbs.
Summary
origin: continuation of descending thoracic aorta at T12
course: descend...
Article
Abdominal aortic aneurysm
Abdominal aortic aneurysms (AAA) are focal dilatations of the abdominal aorta measuring 50% greater than the proximal normal segment or >3 cm in maximum diameter.
They can be confined to the abdominal aorta or continue from the thoracic aorta as part of a thoraco-abdominal aneurysm (TAAA).
The...
Article
Abdominal aortic aneurysm rupture
Abdominal aortic aneurysm (AAA) rupture is a feared complication of abdominal aortic aneurysm and is a surgical emergency. It is part of the acute aortic syndrome spectrum.
Epidemiology
Abdominal aortic aneurysms are common and affect ~7.5% of patients aged over 65 years 6.
The risk of ruptur...
Article
Abdominal aortic aneurysm (summary)
This is a basic article for medical students and other non-radiologists
Abdominal aortic aneurysms (AAA) are focal dilatations of the abdominal aorta that are 50% greater than the proximal normal segment or >3 cm in maximum diameter.
Reference article
This is a summary article; read more in o...
Article
Abdominal aortic injury
Abdominal aortic injuries are a very rare form of traumatic aortic injury and are much less common than thoracic aortic injury.
Epidemiology
Aortic injury occurs in <1% of blunt trauma patients, with abdominal aortic injury representing only ~5% of all aortic injuries 1. Males are more freque...
Article
Abdominal compartment syndrome
Abdominal compartment syndrome is a disease defined by the presence of new end-organ dysfunction secondary to elevated intra-abdominal pressure. Radiological diagnosis is difficult and usually suggested when a collection of imaging findings are present in the appropriate clinical setting or if t...
Article
Abdominal radiology for students (curriculum)
This is a basic article for medical students and other non-radiologists
Abdominal radiology curriculum for medical students is broadly split into content that refers to imaging (the test and findings) and conditions that are considered key for this stage of training.
Some non-abdominal conditi...
Article
Abernethy malformation
Abernethy malformations are rare vascular anomalies of the splanchnic venous system. They consist of congenital portosystemic shunts resulting from the embryonic vessels' persistence.
Epidemiology
Type I malformations are thought to occur only in females, while type II has a male predominance...
Article
Aberrant internal carotid artery
Aberrant internal carotid artery is a variant of the internal carotid artery and represents a collateral pathway resulting from involution of the normal cervical portion (first embryonic segment) of the internal carotid artery 5.
Gross anatomy
There is consequent enlargement of the usually sma...
Article
Aberrant left pulmonary artery
Aberrant left pulmonary artery, also known as pulmonary sling, represents an anatomical variant characterized by the left pulmonary artery arising from the right pulmonary artery and passing above the right main bronchus and in between the trachea and esophagus to reach the left lung. It may lea...
Article
Aberrant right subclavian artery
Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are among the commonest aortic arch anomalies.
Epidemiology
The estimated incidence is 0.5-2% 1.
Associations
as can be expected from the embryological development of the artery, the right recurrent laryngeal nerve...
Article
Abnormal ductus venosus waveforms
Abnormal ductus venosus waveforms can arise in a number of conditions ranging from aneuploidy to vascular malformations and fetal tumors. "A wave" reversal can be seen in 5% of euploid fetuses 9.
Pathology
Abnormal waveforms in fetal ductus venosus flow assessment can occur in a number of situ...
Article
Absent azygos vein
An absent azygos vein is a very uncommon variant in which the azygos vein fails to develop. In cases of agenesis of the azygos vein, the hemiazygos and accessory hemiazygos veins play an important role in venous drainage, accounting for drainage of both the right and left intercostal veins 1-3.
...
Article
Absent ductus venosus
Agenesis of the ductus venosus (ADV) is a rare fetal vascular anomaly.
Epidemiology
According to the data obtained from the screening tests performed at 11-14 weeks of pregnancy, its incidence is reported to be 1/2500 12.
Pathology
In a large case series, Acherman et al. 13 defined five drai...
Article
Absent infrarenal inferior vena cava
An absent infrarenal inferior vena cava can be congenital, due to the failure of development of the posterior cardinal and supracardinal veins, or acquired, as a result of intrauterine or perinatal inferior vena cava thrombosis.
Epidemiology
It is an extremely rare anomaly.
Clinical presentat...
Article
Acceleration index
Acceleration index is an indirect sonographic sign to assess renal artery stenosis 1.
Usage
Acceleration index is used in the Doppler assessment of the renal arteries when assessing for renal artery stenosis.
Measurement
Acceleration index is calculated by subtracting the initial systolic ve...
Article
Access guidewires
Access guidewires are interventional procedures wires used during the first steps of interventions, to secure stable access and sheaths/catheter insertion. They are quickly exchanged for a navigation wire thereafter.
The most common access wires are1:
Cope Mandril wire
Nitrex wire
Properties...
Article
Accessory appendicular artery
The accessory appendicular artery, also known as the artery of Seshachalam, is a branch of the posterior cecal artery. It arises from the ileocolic artery, and runs in the mesoappendix.
The exact prevalence of this accessory artery and its impact upon the risk of appendicitis varies among studi...
Article
Accessory hemiazygos vein
The accessory (or superior) hemiazygos vein forms part of the azygos system and along with the hemiazygos vein, it is partially analogous to the right-sided azygos vein. It drains the left superior hemithorax.
Terminology
Spelling it "hemiazygous" when referring to the vein is incorrect, rega...
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