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
Ulcer (soft tissue)
The term ulcer refers to a break in the skin, epithelium, or mucous membrane resulting in discontinuity of the surface tissues, necrosis, and often pus formation 1.
Risk factors
immunocompromise (e.g. diabetes mellitus) 1
poor perfusion (e.g. peripheral vascular disease) 1,2
immobile patient...
Article
Meyers and McKeever classification of ACL avulsion fractures
Meyers and McKeever classification is used to categorize ACL avulsion fractures.
Usage
The Meyers and McKeever classification is the most frequently used system (c. 2024) to describe ACL avulsion fractures 2.
Classification
Under the Meyers and McKeever system (with modifications by Zariczny...
Article
Periportal halo (CT/US)
Periportal halo or periportal collar sign refers to a zone of low attenuation seen around the intrahepatic portal veins on contrast-enhanced CT or hypoechogenicity on liver ultrasound. It likely represents periportal edema, which is often used as a synonymous term. Periportal haloes may occur ar...
Article
Skeletal survey (overview)
The skeletal survey is a radiographic series performed to survey the entire skeleton (axial skeleton, upper and lower limbs) for pathology or injury. Specific projections vary depending on the clinical indication and the institution's protocol.
There are various clinical indications that may wa...
Article
Bowl of grapes sign
The bowl of grapes sign has been described in synovial sarcoma. It refers to the characteristic multilobulated lesion subdivided by multiple septa, forming large cystic foci with regions of hemorrhage.
Article
Psoriasis
Psoriasis is an inflammatory dermatological disease with several variants. The most common variant is plaque psoriasis, other variants of the disease are guttate, erythrodermic and pustular psoriasis 1.
Epidemiology
There is a geographic variation in the prevalence of psoriasis such that popul...
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
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
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
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
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
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...
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