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.
16,924 results
Article
Divot sign (antenatal ultrasound)
A divot sign is a grey-scale ultrasound sign of a nuchal cord. It refers to the impressions of the umbilical cord on the skin of the posterior aspect of the fetal neck on grey-scale imaging on the sagittal plane during an antenatal scan 1. It is a specific sign used to identify a nuchal cord whe...
Article
Peripheral pulmonary carcinoid tumor
Peripheral pulmonary carcinoid tumor refers to a subtype of pulmonary carcinoid tumors that arise within the periphery of the lung. They are considered less common than the more centrally-located bronchial carcinoid tumors.
Clinical presentation
Many patients tend to be asymptomatic 2. Presen...
Article
Alar fascia
The alar fascia is a thin fibroareolar membrane separating the (anterior) true retropharyngeal space from the (posterior) danger space. It is the ventral component of the deep layer of the deep cervical fascia.
Notably, in the well patient, the alar fascia is not usually visible on cross-sectio...
Article
Bipartite patella
A bipartite patella (two-part patella) is a patella with an unfused accessory ossification center, typically at the superolateral aspect.
Epidemiology
The superolateral accessory ossification center of the patella is usually present by 12 years of age and may persist into adult life. Bipartite...
Article
Chagoma (cutaneous)
Chagoma describes a cutaneous erythematous reactive lesion at the insect bite inoculation site of the Trypanosoma cruzi parasite, the causative agent in Chagas disease 1-3. The lesion appears in the weeks after infection and may then persist for several weeks 1,2.
Terminology
Brain chagoma is ...
Article
Brain chagoma
Brain chagoma, central nervous system chagoma, chagasic encephalitis and Chagas encephalitis are terms used to describe brain lesions in immunocompromised individuals with Trypanosoma cruzi parasite infection (Chagas disease).
Terminology
Brain chagoma is distinct from the cutaneous lesion cha...
Article
Spinal arachnoid cyst
Spinal arachnoid cysts are relatively uncommon and may be either intradural (type III meningeal cyst) or extradural (type IA meningeal cyst).
This article specifically focuses on spinal arachnoid cysts. For a general discussion of arachnoid cysts, refer to the main article: arachnoid cyst.
Epi...
Article
Portal venous flow
Portal venous flow is normally towards the liver (hepatopetal), with the normal main portal vein peak systolic velocities usually measuring 20-40 cm/s 1,3.
The mean flow velocity of portal vein in adults is 19.3 cm/s 6.
The normal peak systolic velocity of the portal vein in children ranges fr...
Article
Deep layer of the deep cervical fascia
The deep layer of the deep cervical fascia is one of the three layers of the deep cervical fascia. It encases the paravertebral muscles and forms the perivertebral space. It consists of the perivertebral fascia (the anterior part of which is called the prevertebral fascia) and alar fascia 1-3.
...
Article
Menstrual cup
The menstrual cup is a reusable silicone device designed to be an alternative to tampons and sanitary pads. Various different brands are available but they all have the same shape.
It can be observed on all forms of abdominal imaging and it is worth being familiar with its normal appearances.
...
Article
Bosniak classification of cystic renal masses (version 2019)
The Bosniak classification of cystic renal masses (version 2019), or usually simply Bosniak classification v2019, is an update of the Bosniak criteria published in 2005.
Usage
The Bosniak classification version referred to international guidelines is variable, with the 2022 European and Canadi...
Article
Q-factor
Q-factor is the ratio of the center frequency (f0) to the bandwidth.
High Q-factor transducer indicates a narrow bandwidth and a long spatial pulse length with low damping and narrow bandwidth. This commonly used in doppler ultrasound where a narrow bandwidth is needed to accurately quantify fl...
Article
Misplaced endotracheal tube
A misplaced or malpositioned endotracheal tube is a relatively common complication that is detected on post-intubation radiographs.
Complications
if the ETT is too high it can rub against the vocal cords and cause cord trauma
if the ETT is too low it can selectively intubate the right or left...
Article
Corticobasal degeneration
Corticobasal degeneration (CBD) is an uncommon neurodegenerative disease and is one of the subset of tauopathies.
Terminology
Corticobasal syndrome (CBS) represents the clinical syndrome that is diagnosed clinically, while corticobasal degeneration is only reserved for the subset of cases that...
Article
Dementia with Lewy bodies
Dementia with Lewy bodies (DLB), also known as Lewy body disease, is a neurodegenerative disease (a synucleinopathy to be specific) related to Parkinson disease.
Epidemiology
Dementia with Lewy bodies presents in older patients (onset typically in 50-70 years of age), and is sporadic 1,2,7.
...
Article
Budd-Chiari syndrome
Budd-Chiari syndrome, also known as hepatic venous outflow obstruction (HVOO), refers to the clinical picture that occurs when there is partial or complete obstruction of the hepatic veins.
There is no clear consensus regarding the number of occluded veins, some authors claim that there should...
Article
Medical devices in the abdomen and pelvis
Medical devices in the abdomen and pelvis are important to be recognized, just like medical devices of the chest. We often ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications.
Gastrointestinal devices
tube...
Article
Symphalangism
Symphalangism refers to ankylosis or synostosis of the interphalangeal joints (i.e. fusion of the phalanges) in either the toes or the fingers. Less commonly, the metacarpophalangeal joints may be affected.
Epidemiology
One study reports symphalangism of the fifth toe in ~55% (range 40-75%) of...
Article
Popliteal fossa
The popliteal fossa (plural: fossae) is a diamond or rhomboid-shaped fat-filled space in the posterior knee. The space is extremely dynamic, allowing for its neurovascular contents to move during the extreme range of motion produced by knee flexion and extension.
Gross anatomy
Boundaries
supe...
Article
Posterior cruciate ligament
The posterior cruciate ligament (PCL) is one of the two cruciate ligaments that stabilize the knee joint.
Gross anatomy
The posterior cruciate ligament arises from the lateral surface of the medial femoral condyle and inserts onto the posterior lateral intercondylar surface of the tibial plat...
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