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
Right lower lobe collapse
Right lower lobe (RLL) collapse forms a triangular opacity extending from the hilum to the diaphragm. There is less overlap with the heart shadow compared to left lower lobe collapse.
Findings of lower lobe collapse can be grouped together as they are almost identical on both sides.
For a gen...
Article
Anderson and Montesano classification of occipital condyle fractures
The Anderson and Montesano classification is a widely used system for describing occipital condyle fractures. It divides injuries into three types based on morphology and mechanism of injury 1-5.
Classification
type I: impacted type occipital condyle fracture
morphology: comminution of the co...
Article
Os odontoideum
Os odontoideum (plural: ossa odontoidea) is an anatomic variant of the odontoid process of C2 and needs to be differentiated from persistent ossiculum terminale and from a type 2 odontoid fracture. It can be associated with atlantoaxial instability.
Although it was originally thought to be a c...
Article
Percutaneous nephrolithotomy
Percutaneous nephrolithotomy (PCNL) is a surgical procedure for the extraction of large renal calculi. It is usually performed in the operating theater either by a urologist or combined urologist-radiologist team.
Indication
PCNL is used to destroy and remove renal calculi, typically over 2 cm...
Article
Germ cell tumors of the ovary
Germ cell tumors of the ovary account for approximately 15-20% of all ovarian tumors. In children and adolescents, up to 60% of ovarian tumors can be of germ cell origin.
They include:
ovarian teratoma(s): commonest primary benign tumor of ovary and commonest germ cell tumor:
mature (cystic) ...
Article
Orthopantomography
The orthopantomogram (also known as an orthopantomograph, pantomogram, OPG or OPT) is a panoramic single image radiograph of the mandible, maxilla and teeth. It is often encountered in dental practice and occasionally in the emergency department; providing a convenient, inexpensive and rapid way...
Article
Aortic arch
The aortic arch represents the direct continuation of the ascending aorta and represents a key area for a review of normal variant anatomy and a wide range of pathological processes that range from congenital anomalies to traumatic injury.
Summary
origin: continuation of the ascending aorta at...
Article
Flame sign (carotid)
The flame sign refers to a gradual tapering of contrast opacification in the mid-cervical internal carotid artery, sparing the carotid bulb. The sign can be observed on angiography (digital subtraction angiography 1, CT angiography 1, or contrast-enhanced MR angiography 2) in either of two scena...
Article
Hepatic lymphoma
Hepatic lymphoma is a term given to any form of hepatic involvement with lymphoma. This can be broadly divided into:
secondary hepatic involvement with lymphoma: most common by far, many tend to be non-Hodgkin lymphoma (NHL) 1
primary hepatic lymphoma: extremely rare
Pathology
Risk factors f...
Article
Tinnitus causes (mnemonic)
A mnemonic to remember the commonest causes of tinnitus is:
HAMMER
Mnemonic
H: hypertension
A: anemia / acoustic neuroma
M: migraine / Menière's disease
M: medication (quinine, NSAIDs, streptomycin)
E: ear pathology (wax, foreign body, otitis media)
R: rare (temporomandibular joint ...
Article
Avulsion injury
Avulsion injuries or fractures occur where the joint capsule, ligament, tendon or muscle attachment site is pulled off from the bone, usually taking a fragment of cortical bone. Avulsion fractures are commonly distracted due to the high tensile forces involved. There are numerous sites at which ...
Article
Biliary atresia
Biliary atresia is a congenital biliary disorder that is characterized by an absence or severe deficiency of the extrahepatic biliary tree. It is one of the most common causes of neonatal cholestasis, often causing cirrhosis immediately and leading to death and accounts for over half of children...
Article
Kaposiform hemangioendothelioma
Kaposiform hemangioendotheliomas are rare, locally invasive vascular tumors that often present in infancy, most commonly as an enlarging cutaneous mass 1,2. They are classified as distinct from tufted angiomas in the ISSVA classification of vascular anomalies. However, some consider it to be on ...
Article
Mid-talar axis
The mid-talar axis represents a line drawn down the longitudinal axis of the talus and can be drawn on lateral and DP radiographs.
Measurement
Independent on the view on which the line is drawn, it should bisect the neck of the talus and the head.
On the lateral and DP views, the line should...
Article
Perivascular spaces
Perivascular spaces, also known as Virchow-Robin spaces, are fluid-filled spaces that surround small arterioles, capillaries and venules in the brain. Those that surround perforating vessels are frequently seen on routine MRI imaging.
Despite having been described well over a century ago and se...
Article
Parastomal hernia
Parastomal hernias (alternative plural: herniae) are defined as the protrusion of abdominal contents through an abdominal wall defect in the vicinity of the stoma.
Classification
The hernia may contain a loop of bowel forming the stoma itself, omentum, and/or intestinal loops other than that f...
Article
MitraClip device
A MitraClip is a device for percutaneous mitral valve repair. It is a percutaneous edge-to-edge attachment system that mimics the surgical procedure. This technique creates a tissue bridge between the anterior and posterior leaflets, employing one clip deployed through transseptal catheterizatio...
Article
Benign and malignant characteristics of breast lesions at ultrasound
Benign and malignant characteristics of breast lesions at ultrasound allow the classification as either malignant, intermediate or benign based on work published by Stavros et al. in 1995.
Radiographic features
Ultrasound
Malignant characteristics (with positive predictive values)
sonographi...
Article
Accessory left atrial appendage
An accessory left atrial appendage is a frequent fortuitous finding in cardiac imaging, encountered in ~10% of patients. They are more often seen as a small diverticular structure projecting from the right upper side of the left atrial wall.
Differential diagnosis
it must not be confused with ...
Article
Ischemic colitis
Ischemic colitis refers to inflammation of the colon secondary to vascular insufficiency and ischemia. It is sometimes considered under the same spectrum as intestinal ischemia. The severity and consequences of the disease are highly variable.
Epidemiology
Ischemic bowel is typically a disease...
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