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.
More than 200 results
Article
PSA density
The PSA density (PSAD) is calculated at diagnosis of prostate cancer and is the serum prostate-specific antigen (PSA) level (ng/mL) divided by the prostate gland's volume (mL), resulting in a value in the units ng/mL2 1. Prostate volume is calculated from measurements obtained using transrectal ...
Article
Cerebral abscess
A cerebral abscess is a focal area of necrosis starting in an area of cerebritis surrounded by a membrane. It is a potentially life-threatening condition requiring prompt radiological identification and rapid treatment. Fortunately, MRI is usually able to convincingly make the diagnosis, disting...
Article
Prostatomegaly
Prostatomegaly is a general term used to describe enlargement of the prostate gland from whatever cause. Usually, the prostate is considered enlarged on imaging when its volume measures >30 mL 3.
Terminology
The term prostatomegaly is often used interchangeably with benign prostatic hyperplas...
Article
Chronic exertional compartment syndrome
Chronic exertional compartment syndrome (CECS), previously known as anterior tibial syndrome, is a type of compartment syndrome that is brought on by exercise.
Epidemiology
The exact prevalence is not known since sufferers may modify the way they exercise and therefore never present. CECS can ...
Article
Status epilepticus
Status epilepticus is an acute and prolonged seizure that persists for a sufficient length of time or is repeated frequently enough that recovery between attacks does not occur. It is a clinical emergency associated with high morbidity and mortality.
Terminology
Status epilepticus is a broad t...
Article
Methylguanine-DNA methyltransferase (MGMT)
O6-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme that is important in predicting the effects of alkylating chemotherapeutic agents (e.g. temozolomide) in the treatment of high-grade gliomas (astrocytomas and glioblastomas).
Mechanism of action
MGMT is an enzyme that removes...
Article
Transient intussusception
Transient or uncomplicated intussusception is known to occur in adults and children and can be considered physiological. Given the condition's transient nature, it is probably underdiagnosed. The main factors distinguishing transient from intussusceptions requiring surgical intervention are abse...
Article
Fibularis brevis muscle
The fibularis brevis muscle, also known as the peroneus brevis muscle, is a muscle in the lateral compartment of the leg. It lies deep/medial to the adjacent fibularis longus, and is a shorter and smaller muscle. Both brevis and longus travel together along the lateral aspect of the ankle within...
Article
Bacillus Calmette–Guérin (BCG) vaccine
The bacillus Calmette–Guérin (BCG) vaccine is the only vaccine available for Mycobacterium tuberculosis and despite its global use for 90 years, with proven efficacy and a good safety record, has well-known limitations. It provides only limited protection against pulmonary tuberculosis.
The vac...
Article
Intrinsic muscles of the hand (mnemonic)
Useful mnemonics to recall the intrinsic muscles of the hand and some of their features include:
All For One And One For All
PAd DAb
FOAL/LOAF
Mnemonics
All For One And One For All
This mnemonic recalls the intrinsic muscles of the hand in their relative palmar anatomical position from lat...
Article
Pneumobilia vs portal venous gas (mnemonic)
Pneumobilia and portal venous gas are two causes of an intrahepatic branching gas pattern. The two have different causes and implications and need to be distinguished on imaging, and a simple mnemonic can help.
Mnemonic
A simple mnemonic for remembering the difference in appearance is:
portal...
Article
Sternoclavicular sclerosis (mnemonic)
Mnemonics for sternoclavicular sclerosis include:
STOP
SPOT
Mnemonic
S: SAPHO syndrome
T: traumatic osteolysis
O: osteomyelitis/osteosarcoma
P: Paget disease
Article
Reverse figure 3 sign (esophagus)
The reverse figure 3 sign (also known as the E sign) is seen on barium swallows in patients with coarctation of the aorta and is the medial equivalent of the figure 3 sign seen on plain chest radiographs. It is formed by prestenotic dilatation of the ascending aorta, indentation of the coarctati...
Article
Bone cortical lesions (mnemonic)
A mnemonic for bony cortical lesions is:
Fear Of Missing Out S
Mnemonic
F: fibrosarcoma
O: osteoid osteoma
M: metastasis
O: osteomyelitis
S: stress fracture
Article
Pregnancy-associated plasma protein-A
Pregnancy-associated plasma protein-A (PAPP-A) is a protein found in the maternal circulation and is produced by the placenta. The PAPP-A gene has been assigned to human chromosome 9q33.1 and contains 22 exons 5. PAPP-A values tend to rise exponentially during pregnancy and the reference range d...
Article
Calcaneal lesions (mnemonic)
A mnemonic for calcaneal lesions is:
BIG G
Mnemonic
B: bone cyst (unicameral)
I: intraosseous lipoma
G: ganglion (intraosseous)
G: giant cell tumor
Article
Lung torsion
Lung torsion is the rotation of a lung or lung lobe about its bronchovascular pedicle and resulting in ischemia. It is very rare and typically occurs in the setting of lobectomy or pneumonectomy. It has also been reported as a rare complication of less invasive procedures such as video-assisted ...
Article
Acetabular protrusion
Acetabular protrusion, also known as protrusio acetabuli, is intrapelvic displacement of the acetabulum and femoral head, so that the femoral head projects medial to the ilioischial line. It should be differentiated from coxa profunda.
Pathology
Acetabular protrusion is divided into primary an...
Article
Generalized colitis (mnemonic)
A mnemonic to remember the causes of generalized colitis is:
I3NR
Mnemonic
I: infectious colitis e.g. E. coli, cytomegalovirus
I: inflammatory, e.g. pseudomembranous colitis, Crohn disease, ulcerative colitis
I: ischemic colitis
N: neoplastic, e.g. lymphoma
R: radiation colitis
Article
Pneumatosis intestinalis (mnemonic)
A helpful mnemonic for remembering the causes of pneumatosis intestinalis is:
ChIPS
Mnemonic
C: chronic obstructive pulmonary disease
I: ischemia
P: pneumatosis cystoides intestinalis
S: scleroderma/steroids
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