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
AO/OTA classification of acetabular fractures
The AO/OTA classification is one of the most frequently used systems for classifying acetabular fractures. Like other fractures, they are divided into three groups subject to the severity and complexity of the respective injury 1.
type A: partial articular isolated wall or column fracture
A1: ...
Article
Signet ring sign (bronchiectasis)
The signet ring sign is seen in bronchiectasis when the dilated bronchus and accompanying pulmonary artery branch are seen in cross-section. The bronchus and artery should be the same size, whereas in bronchiectasis, the bronchus is markedly dilated.
The signet ring sign has been also described...
Article
Duplication of the inferior vena cava
Duplication of the inferior vena cava is a relatively rare but well described vascular anomaly. This caval abnormality had an increased association with renal anomalies like crossed fused ectopia or circumaortic renal collar 1,2.
Epidemiology
The incidence of inferior vena cava duplication is ...
Article
Rectosigmoid ratio
The rectosigmoid ratio is a measurement of the diameter of the rectum divided by that of the sigmoid colon during contrast enema. It is of particular use in the diagnosis of Hirschsprung disease.
Normal children have a rectum that is larger than the sigmoid (i.e. rectosigmoid ratio >1). In fact...
Article
Reverse Hill-Sachs defect
Reverse Hill-Sachs defect, also known as a McLaughlin lesion, is defined as an impaction fracture of anteromedial aspect of the humeral head following posterior dislocation of the humerus. It is of surgical importance to identify this lesion and correct it to prevent osteonecrosis.
Radiographic...
Article
Lincoln sign on bone scintigraphy
Lincoln sign on bone scintigraphy (also known as black beard sign) is one of the signs of Paget disease on the radionuclide bone scan when the disease involves the mandible. The sign might be seen when the extensive mandibular involvement with Paget disease results in the uptake of the radiotrac...
Article
Case discussion
Case discussion refers to relevant teaching points and imaging features relating to your particular case (but not of that particular condition); this section is below your images and you can link related articles into this section.
If you are struggling to write a case discussion remember it c...
Article
Intraconal orbital compartment
The intraconal orbital compartment or intraconal space is the conical space within the orbit and musculofascial cone, the base of which is anterior and is formed by the posterior half of the globe. The sides are formed by the extraocular muscles and their surrounding fascia which pass posteriorl...
Article
Pericardiophrenic vein
Pericardiophrenic veins are the veins that accompany the pericardiophrenic artery and phrenic nerve along either side of the middle mediastinum. They drain tributaries from the superior diaphragm and pericardium, usually terminating in the floor of the respective brachiocephalic vein, but also p...
Article
Thumb sign (disambiguation)
The term thumb sign is used to refer to a number of separate radiological appearances, including:
thumb sign (Marfan disease) - a clinical sign
thumb sign (epiglottitis)
thumb sign (chordoma)
Article
Meyers and McKeever classification of ACL avulsion fractures
Meyers and McKeever classification is used to categorise 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 oedema, which is often used as a synonymous term. Periportal haloes may occur a...
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 haemorrhage.
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 tumours of the ovary
Germ cell tumours of the ovary account for approximately 15-20% of all ovarian tumours. In children and adolescents, up to 60% of ovarian tumours can be of germ cell origin.
They include:
ovarian teratoma(s): commonest primary benign tumour of ovary and commonest germ cell tumour:
mature (cys...
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