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.
16,919 results
Article
Cerebral microhemorrhage
Cerebral microhemorrhages, or cerebral microbleeds, are small focal intracerebral hemorrhages, often only visible on susceptibility-sensitive MRI sequences.
Pathology
Common etiologies
cardiac bypass for surgery 15,31
cavernous malformations 1,8
especially Zabramski classification type IV m...
Article
Hepatic encephalopathy
Hepatic encephalopathy, also known as acute hyperammonemic encephalopathy or portosystemic encephalopathy, refers to a spectrum of neuropsychiatric abnormalities occurring in patients with liver dysfunction and portal hypertension. It results from exposure of the brain to excessive amounts of am...
Article
Multiple system atrophy cerebellar type (MSA-C)
Multiple system atrophy cerebellar type (MSA-C), previously known as olivopontocerebellar degeneration, is a neurodegenerative disease, and one of the clinical phenotypes of multiple systemic atrophy (MSA).
Terminology
The prevailing thought is that that olivopontocerebellar degeneration, Shy-...
Article
Mature cystic ovarian teratoma
Ovarian dermoid cyst and mature cystic ovarian teratoma are terms often used interchangeably to refer to the most common ovarian neoplasm. These slow-growing tumors contain elements from multiple germ cell layers and can be assessed with ultrasound or MRI.
Terminology
Although they have very ...
Article
Floating balls sign
The floating balls sign refers to the appearance of multiple mobile globules/spherules of solid, usually fatty, tissue within an adnexal cyst. It is pathognomonic for ovarian mature cystic teratoma 1,2.
Terminology
Alternative names include the meatballs 3, truffle sign 4, and boba sign 13.
...
Article
Frontal lobe
The frontal lobe is by far the largest of the four lobes of the cerebrum (other lobes: parietal lobe, temporal lobe, and occipital lobe), and is responsible for many of the functions which produce voluntary and purposeful action.
Gross anatomy
The frontal lobe is the largest lobe accounting fo...
Article
Rectum
The rectum is the last part of the large intestine. It is located within the pelvis and is the continuation of the sigmoid colon after the rectosigmoid junction and continues as the anal canal at the anorectal angle created by puborectalis.
Gross anatomy
At the level of the S3 vertebral body,...
Article
Gastropericardial fistula
Gastropericardial fistulas are rare abnormal communications between the stomach and the pericardial sac. This is a life-threatening condition that can lead to impaired cardiac function, sepsis and eventually death.
Clinical presentation
Patients with gastropericardial fistula may present with ...
Article
Gibbus deformity
A gibbus deformity is a short-segment structural thoracolumbar kyphosis resulting in sharp angulation.
Pathology
Etiology
There are a number of causes which can be divided into congenital and acquired.
Congenital
achondroplasia
cretinism (congenital hypothyroidism)
Apert syndrome
Coffin-...
Article
Scoliosis
Scoliosis (plural: scolioses) is defined as an abnormal lateral curvature of the spine. It is quite common in young individuals and is often idiopathic and asymptomatic. In some cases, however, it is the result of underlying structural or neurological abnormalities.
Terminology
Early onset sco...
Article
Whirlpool sign (testicular torsion)
The whirlpool sign of the spermatic cord is a direct sign of testicular torsion, both complete and incomplete (i.e. <360°). It is considered to be the most specific and sensitive sign for testicular torsion.
Terminology
The term whirlpool sign is used in other contexts: see whirlpool sign (dis...
Article
Testicular torsion
Testicular torsion occurs when a testis torts on the spermatic cord resulting in the cutting off of blood supply. The most common symptom is acute testicular pain and the most common underlying cause, a bell-clapper deformity. The diagnosis is often made clinically but if it is in doubt, an ultr...
Article
Tarlov cyst
Tarlov cysts, also called perineural cysts, are CSF-filled dilatations of the nerve root sheath at the dorsal root ganglion (posterior nerve root sheath). These are type II spinal meningeal cysts that are, by definition, extradural but contain neural tissue.
Most Tarlov cysts are asymptomatic, ...
Article
Ischiofemoral impingement
Ischiofemoral impingement refers to the impingement of soft tissues between the ischial tuberosity and lesser trochanter of the femur.
Clinical presentation
Patients with ischiofemoral impingement present with chronic pain in the groin and/or buttock, without a history of traumatic injury. Pa...
Article
Nabothian cyst
Nabothian cysts, also known as retention cysts of the cervix 11, are non-neoplastic cystic lesions that occur in relation to the uterine cervix.
Terminology
Nabothian is generally written without capitalization, i.e. "nabothian", and not "Nabothian", as it is an adjectival form derived from a ...
Article
Adrenal adenoma
Adrenal adenomas (alternative plural: adenomata) are the most common adrenal lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adr...
Article
Urinary bladder
The urinary bladder (more commonly just called the bladder) is a distal part of the urinary tract and is an extraperitoneal structure located in the true pelvis 6. Its primary function is as a reservoir for urine.
Gross anatomy
The bladder has a triangular shape with a posterior base (fundus)...
Article
Kidneys
The kidneys are paired retroperitoneal organs that lie at the level of the T12 to L3 vertebral bodies.
Gross anatomy
Location
The kidneys are located to either side of the vertebral column in the perirenal space of the retroperitoneum, within the posterior abdominal wall. The long axis of the...
Article
Ureter
The ureter is a paired fibromuscular tube that conveys urine from the kidneys in the abdomen to the bladder in the pelvis.
Gross anatomy
The ureter is 25-30 cm long and has three parts:
abdominal ureter: from the renal pelvis to the pelvic brim
pelvic ureter: from the pelvic brim to the bla...
Article
Reticuloendothelial system
The reticuloendothelial system (RES) comprises a number of tissues:
spleen
bone marrow
liver Kupffer cells