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
Halo sign (chest)
The halo sign in chest imaging is a feature seen on lung window settings consisting of ground glass opacity surrounding a pulmonary nodule, mass, or consolidation. It is typically seen in angioinvasive aspergillosis.
Pathology
It is a non-specific finding which can represent partial alveolar f...
Article
Scatter to primary ratio
The scatter to primary ratio is a ratio of the scattered radiation to the primary unscattered radiation transmitted by the object being imaged. Hence, the scatter to primary ratio provides an indication of the degree of unwanted scattered radiation arising from a particular imaging study.
The s...
Article
Ground-glass opacification
Ground-glass opacification/opacity (GGO) is a descriptive term referring to an area of increased attenuation in the lung on computed tomography (CT) with preserved bronchial and vascular markings. It is a non-specific sign with a wide etiology including infection, chronic interstitial disease an...
Article
Meandering main pancreatic duct
Meandering main pancreatic duct denotes a main pancreatic duct that drains normally into the major papilla but performs a hairpin turn (reverse Z-type) or loop (loop-type) in the pancreatic head, in contradistinction to the smooth curvature seen in most cases.
Epidemiology
Their exact incidenc...
Article
Pulmonary hypoplasia
Pulmonary hypoplasia refers to underdevelopment of one or both lungs. This can be rapidly fatal at birth or mild, escaping detection for decades. It is most often secondary to congenital abnormalities that either restrict intrathoracic space or alter pulmonary fluid dynamics.
Epidemiology
Pulm...
Article
Kuwada classification of Achilles tendon tear
The Kuwada classification of Achilles tendon tear was proposed in 1990 4 and remains the most widely used system for describing Achilles tendon rupture ref.
Classification
Achilles tendon tears may be grouped (according to the severity of the tear and degree of retraction) into four types:
ty...
Article
AFS classification of Müllerian anomalies
The American Fertility Society (AFS) classification of Müllerian anomalies is a seven-class system published in 1988, which is used to describe several embryonic Müllerian duct anomalies.
The American Fertility Society is now known as the American Society of Reproductive Medicine (ASRM), and th...
Article
Müllerian duct anomalies
Müllerian duct anomalies (MDAs) are congenital abnormalities that occur when the Müllerian ducts (paramesonephric ducts) do not develop correctly. This may be due to complete agenesis, defective vertical or lateral fusion, or resorption failure.
Epidemiology
MDAs are estimated to occur in 1-5%...
Article
Myocardial infarction with non-obstructive coronary arteries
Myocardial infarction with non-obstructive coronary arteries (MINOCA) is referred to as a syndrome characterized by the clinical characteristics of myocardial infarction but with normal coronary arteries or no significant coronary stenosis on coronary angiography.
Epidemiology
The suggested pr...
Article
Cannonball metastases (lungs)
Cannonball metastases refer to multiple large, well-circumscribed, round pulmonary metastases that appear not unsurprisingly like cannonballs. The French terms "envolée de ballons" and "lâcher de ballons", which translate to "balloons release", are also used to describe this same appearance.
M...
Article
Shoulder radiograph (an approach)
Shoulder radiographs are common films to see in the Emergency Department, especially during the weekend after sporting events.
Systematic review
Choosing a search strategy and utilizing it consistently is a helpful method to overcome common errors seen in diagnostic radiology. The order in whi...
Article
Coronary artery disease
Coronary artery disease (CAD) is primarily due to the narrowing of the coronary arteries due to atherosclerosis, which results in myocardial ischemia and is the leading cause of mortality globally.
Diagnosis
The diagnosis of coronary artery disease is based on typical imaging criteria either ...
Article
Low-lying placenta
A low-lying placenta occurs when it extends into the lower uterine segment, and its edge lies close to the internal os of the cervix without covering it.
Terminology
The term should be used when the edge of the placenta is <2 cm from the cervical internal os in pregnancies >16 weeks gestation ...
Article
Bethesda system for reporting thyroid cytopathology
The Bethesda system for reporting thyroid cytopathology comprises six categories of pathological reporting of thyroid FNA, with each category linked to a malignancy risk.
Usage
The Bethesda system was first published in 2010 and subsequently revised with the third edition published in 2023 to ...
Article
Placenta previa
Placenta previa is an abnormally low-lying placenta covering the internal cervical os. As a common cause of antepartum hemorrhage, placenta previa is a potentially life-threatening condition for both mother and infant. As such, antenatal diagnosis is essential to prepare for childbirth adequatel...
Article
Angiography catheter (overview)
Angiography catheters are thin, flexible tubes used in various diagnostic and therapeutic angiographic procedures.
Indications
Angiography catheters are used in a wide range of interventional procedures 1:
vascular access, e.g. for fluid and drug administration, blood sample aspiration
diagn...
Article
Small cell carcinoma of the prostate
Small cell carcinomas of the prostate (SCCP) or small cell neuroendocrine carcinomas of the prostate are neuroendocrine tumors and are characterized by aggressive behavior and a proliferation of small cells.
Epidemiology
Small cell neuroendocrine carcinomas of the prostate are rare 1,2 and mak...
Article
Gustilo and Anderson classification of open fractures
The Gustilo and Anderson classification, sometimes referred to just as the Gustilo classification, is the current (c. 2025) most commonly used system to describe open fractures 1.
Usage
The system is routinely used to guide the antimicrobial management of open fractures.
Classification
Over ...
Article
Idiopathic inflammatory myopathy
Idiopathic inflammatory myopathy is applied to a group of autoimmune inflammatory muscle disorders (myositis). Which specific disorders are included in this group has evolved, particularly with advances in the discovery of myositis-specific antibodies 1,2.
Diagnosis
The diagnosis of idiopathic...
Article
Ectopia cordis
Ectopia cordis is an extremely rare congenital malformation where the heart is partially or totally outside the thoracic cavity.
Epidemiology
The incidence is ~7 (range 5.5-7.9) per 1,000,000 live births 10.
Pathology
Ectopia cordis results from the failure of lateral mesoderm migration int...
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