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.
16,858 results found
Article
1.5 T vs 3.0 T
Comparing 1.5 T vs 3.0 T (1.5 tesla vs 3.0 tesla) MRI systems identifies several differences; a 3 T system has
increased signal-to-noise ratio (SNR)
increased spatial resolution
increased temporal resolution
increased specific absorption rate (SAR)
increased acoustic noise
Terminology
It...
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
Second branchial cleft cyst
Second branchial cleft cysts are a cystic dilatation of the remnant of the second branchial cleft (see branchial apparatus), and along with second branchial fistulae and sinuses accounts for 95% of all branchial cleft anomalies.
Clinical presentation
Although a congenital abnormality, they ten...
Article
Chondrocalcinosis (mnemonic)
Mnemonics for chondrocalcinosis include:
3 Cs
HOGWASH
Mnemonics
3 Cs
C: crystals e.g. CPPD, sodium urate (gout)
C: cations e.g. calcium (any cause of hypercalcemia), copper, iron
C: cartilage degeneration (e.g. osteoarthritis, acromegaly, ochronosis)
HOGWASH
H: hyperparathyroidism, hyp...
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 It is no longer in use having been superseded by the 6-tier BI-RADS classification system first published in 1992 1.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
5th metacarpal pit
The 5th metacarpal pit refers to the normal exaggeration of the pit-like depression in the head of fifth metacarpal 1.
Differential diagnosis
It should not be mistaken for a boxer fracture (old or new) or an erosion.
Article
ABER position
The ABER position relates to MR arthrography of the shoulder joint and is a mnemonic for ABduction and External Rotation.
In this position, labral tears are made conspicuous by tightening the inferior glenohumeral labroligamentous complex (which are also the most important glenohumeral ligament...
Article
AIDS cholangiopathy
AIDS cholangiopathy refers to an acalculous, secondary opportunistic cholangitis that occurs in AIDS patients as a result of immunosuppression 1.
Pathology
Characterized by multiple irregular strictures essentially indistinguishable from primary sclerosing cholangitis (PSC). There are four pa...
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 hernia
Abdominal hernias/herniae may be congenital or acquired and come with varying eponyms. They are distinguished primarily based on type, location and content.
Epidemiology
75-80% of all hernias are inguinal ref.
Pathology
Content of the hernia is variable, and may include:
small bowel loops
...
Article
Abducens nerve
The abducens nerve is the sixth cranial nerve (CN VI). It is a motor nerve responsible for abduction of the eye (TA: nervus abducens or nervus cranialis VI). It courses from the abducens nucleus, located in the dorsal pons, up to the cavernous sinus, via a long cisternal segment that is prone to...
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 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
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
Accessory right inferior hepatic vein
An accessory right inferior hepatic vein is the most common variation of the hepatic veins, and may be multiple 1. It is present in up to 48% of the population and drains the posteroinferior part of the right lobe directly into the inferior vena cava (IVC) 1-3.
Variations in hepatic vascular an...
Article
Achalasia
Achalasia (primary achalasia) is a failure of organized esophageal peristalsis that causes impaired relaxation of the lower esophageal sphincter, resulting in food stasis and often marked dilatation of the esophagus.
Obstruction of the distal esophagus from other non-functional etiologies, not...
Article
Achilles tendon tear
Achilles tendon tears are the most common ankle tendon injuries, with microtears to full thickness tendon tears of the Achilles tendon and are most commonly seen secondary to sports-related injury, especially squash and basketball.
Epidemiology
There is strong male over-representation presumab...
Article
Achondroplasia
Achondroplasia is a congenital genetic disorder resulting in rhizomelic dwarfism and is the most common skeletal dysplasia. It has numerous distinctive radiographic features.
Epidemiology
It occurs due to sporadic mutations in the majority of cases but can be inherited as an autosomal dominan...
Article
Vestibular schwannoma
Vestibular schwannomas, also known as acoustic neuromas, are relatively common tumors that arise from the vestibulocochlear nerve (CN VIII) and represent ~80% of cerebellopontine angle (CPA) masses. Bilateral vestibular schwannomas are strongly suggestive of neurofibromatosis type 2 (NF2).
On i...
Article
Acquired aortic conditions
Acquired aortic conditions include:
aortic dissection
aortic rupture/transection
ascending aortic aneurysm
aortitis
thoracic aortic injury
abdominal aortic aneurysm
inflammatory abdominal aortic aneurysm
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