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.
746 results found
Article
Ulnar variance
Ulnar variance (also known as Hulten variance) refers to the relative lengths of the distal articular surfaces of the radius and ulna and is primarily a plain radiographic determination.
Ulnar variance may be:
neutral (both the ulnar and radial articular surfaces at the same level)
positive ...
Article
Chronic bilateral airspace opacification (differential)
Chronic bilateral airspace opacification is a subset of the differential diagnosis for airspace opacification. An exhaustive list of all possible causes of chronic bilateral airspace opacities is long, but a useful framework is as follows:
inflammatory
sarcoidosis
granulomatosis with polyangi...
Article
Diffuse pulmonary nodules
Diffuse pulmonary nodules are usually seen as multiple pulmonary nodular opacifications on a HRCT chest scan. They can signify disease processes affecting either the interstitium or the airspace. They can range from a few millimeters to up to 1 cm and when very small and numerous there can be so...
Article
Bat wing opacities (lungs)
Bat wing opacities, also known as butterfly opacities, refer to a pattern of bilateral perihilar lung shadowing. It is classically described on a frontal chest radiograph but can also refer to appearances on chest CT 3,4.
Differential diagnosis
Bat wing pulmonary opacities can be caused by:
p...
Article
Consolidation
Consolidation describes increased lung attenuation sufficient to obscure bronchial walls and blood vessels (on non-enhanced CT). Patent airways can be identified by the endoluminal gas as an air bronchogram. Consolidation can be caused by any process that evacuates alveolar air such as pneumonia...
Article
Cardiovascular shunts
Cardiovascular (cardiac) shunts are abnormal connections between the pulmonary and systemic circulations. Most commonly they are the result of congenital heart disease.
Pathology
Blood can either be shunted from the systemic circulation to pulmonary circulation (i.e. 'left-to-right shunt') or ...
Article
Acute unilateral airspace opacification (differential)
Acute unilateral airspace opacification is a subset of the differential diagnosis for airspace opacification.
Differential diagnosis
The exhaustive list of all possible causes would be huge, but a useful framework includes:
pus (i.e. pulmonary infection)
bacterial pneumonia
fungal pneumon...
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
Upper lobe bronchiectasis
Distribution of bronchiectasis can help in narrowing the differential diagnosis. Upper lobe bronchiectasis is typically seen in:
cystic fibrosis
tuberculosis
Rarely it may be seen with non-tuberculous mycobacterial infection (e.g. MAC infection 2). Traction bronchiectasis in the upper lobes c...
Article
Cyst-like lesions around the knee
There is broad differential for cyst-like lesions around the knee.
Differential diagnosis
Cysts
synovial cyst
popliteal synovial cyst - Baker cyst
ganglion cyst
intra-articular ganglion cyst
ACL ganglion cyst
PCL ganglion cyst
Hoffa fat pad ganglion cyst
extra-articular ganglion cyst
...
Article
Viral encephalitides
Viral encephalitides are the result of brain parenchymal infection by a number of different viruses, many of which have similar presentations and imaging features. Specific diagnosis often requires PCR.
For viral infection of the meninges, please refer to the general article on viral meningiti...
Article
Malignant esophageal neoplasms
Malignant esophageal neoplasms are much more common than benign esophageal neoplasms, especially if the patient is symptomatic.
Pathology
esophageal carcinoma (90%)
esophageal squamous cell carcinoma (SCC)
esophageal spindle cell carcinoma
esophageal adenocarcinoma
esophageal neuroendocri...
Article
Complications following gastric banding
There are many complications that can occur following gastric banding. It is helpful to divide these into early and late post-surgical complications.
Clinical presentation
Although the exact mode of presentation can vary depending on the underlying complication common modes of presentation tha...
Article
Sacroiliitis (differential)
Sacroiliitis (rare plural: sacroiliitides), an inflammation of the sacroiliac joint, can be a manifestation of a wide range of disease processes. The pattern of involvement is helpful for narrowing down the differential diagnosis.
Usually bilateral and symmetrical
enteropathic arthritis
Croh...
Article
Multifocal breast cancer
Multifocal breast cancer refers to two or more individual breast cancers diagnosed at the same time within the same quadrant of the same breast 1.
There is however some heterogeneity in the way the term (as well as the term multicentric breast cancer) is used 4.
NB: When staging such breast c...
Article
Pulmonary nodule
Pulmonary nodules are small, rounded opacities within the pulmonary interstitium. Pulmonary nodules are common and, as the spatial resolution of CT scanners has increased, detection of smaller and smaller nodules has occurred, which are more often an incidental finding.
Classification
Pulmonar...
Article
T1 hyperintense renal lesions
T1 hyperintense renal lesions are a group of lesions that show high signal characteristics on T1-weighted MRI compared to the adjacent normal renal parenchyma.
The differential diagnoses for this group include:
hemorrhagic and/or highly proteinaceous renal cyst
papillary renal cell carcinoma ...
Article
Pediatric calcific discopathy
Pediatric idiopathic intervertebral disc calcification is a rare condition affecting intervertebral discs, adjacent vertebral bodies, and musculo-ligamentous structures, typically resulting in local pain or sensorimotor disturbances. First described by Baron in 1924 1, the underlying etiology is...
Article
Tonsillar herniation
Tonsillar herniation is a type of brain herniation characterized by the inferior descent of the cerebellar tonsils below the foramen magnum 5. Clinically, the presence of tonsillar herniation is often called coning.
The terminology of caudally displaced tonsils is discussed in the article on ce...
Article
Basilar invagination
Basilar invagination, also called basilar impression, is a congenital or acquired craniocervical junction abnormality where the tip of the odontoid process projects above the foramen magnum.
Terminology
The following terms are often used interchangeably because they describe upwards migration...
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