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

Arterial occlusive mesenteric ischemia

Arterial occlusive mesenteric ischemia can be a life-threatening event related to obstruction of the mesenteric arteries, most commonly the superior mesenteric artery (SMA), supplying the small bowel and colon. It is the most common cause of mesenteric ischemia.  Epidemiology  An acute occlusi...
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Cerebral cortical restricted diffusion

Cerebral cortical restricted diffusion, also known as gyriform restricted diffusion, cortical ribboning or cortical ribbon sign, refers to curvilinear hyperintense signal involving the cerebral cortex on DWI images with a corresponding low signal on ADC images. Causes include the following diso...
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CT neck, chest, abdomen-pelvis (NCAP protocol)

The CT neck chest-abdomen-pelvis protocol aims to evaluate the neck, thoracic and abdominal structures using contrast in trauma imaging. The use of contrast facilitates the assessment of pathologies globally whilst minimizing dose by potentially disregarding a non-contrast scan.  Note: This art...
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Bowel wall calcification

Bowel wall calcification is not common and can occur secondary to various mechanisms due to benign, premalignant, or malignant lesions. The differential diagnoses include:  mucinous adenocarcinoma gastrointestinal stromal tumor (GIST) metastatic calcification - due to renal failure hemangio...
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Point-of-care ultrasound (curriculum)

The point-of-care ultrasound (PoCUS) curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core applications of ultrasonography in a point-of-care setting. Point-of-care ultrasound refers to ultrasonography which may be simultaneously performed,...
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Bowel wall fat deposition

Bowel wall fat deposition refers to the infiltration of the submucosa with fat and usually occurs in chronic processes such as inflammatory bowel disease, causing characteristic fat halo sign on CT images.  Other differential diagnoses include: normal variant - particularly in obese patients w...
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Bridging of the sella turcica

Bridging of the sella turcica is the fusion of the anterior and posterior clinoid processes. Epidemiology The prevalence of a sella turcica bridge in a healthy population is estimated to be ~4% (range 1.75-6%) in anatomical and radiographic studies. Pathology It has been reported to occur in...
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Anterior angulation of the coccyx

Anterior angulation of the coccyx may be a normal variant but poses a diagnostic challenge for those considering coccygeal trauma 1. Classification Six types of coccyx have been described initially by Postacchini and Massobrio and later modified by Nathan et al. 2,3: type I: the coccyx is cur...
Article

Osteogenesis imperfecta

Osteogenesis imperfecta (OI) refers to a heterogeneous group of congenital, non-sex-linked, genetic disorders of collagen type I production, involving connective tissues and bones.  The hallmark feature of osteogenesis imperfecta is osteoporosis and fragile bones that fracture easily, as well a...
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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...
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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...
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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.
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Cystic renal diseases

Cystic renal disease can be confusing. There are many conditions, many of which have similar names or are eponymous, and with a few exceptions, are relatively rare. It is easiest to think of them into two separate demographic: pediatric cystic renal diseases adult cystic renal disease
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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) ...
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