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.
16,873 results found
Article
Otsu's method
Otsu’s method, also known as Otsu's threshold algorithm, is an automatic thresholding algorithm used in image processing.
The method separates pixels or voxels from an image into groups based on where their values lie in relation to the image histogram. The method finds threshold values that c...
Article
Human metapneumovirus pulmonary infection
Human metapneumovirus (hMPV) pulmonary infection is a condition reported to cause mild to severe respiratory tract infection, particularly in children, immunocompromised patients, and the elderly 6.
Pathology
Human metapneumovirus (HMPV), is an RNA virus and was first described in 2001. It is ...
Article
Renal cell carcinoma (TNM staging)
The TNM system may be used for staging of renal cell carcinoma. An older but still widely used system for staging of renal cell carcinoma in some practices is the Robson staging system.
TNM staging (8th edition)
Primary tumor staging (T)
Tx: tumor cannot be assessed
T0: tumor not seen
T1
T...
Article
Equivalent dose
Equivalent dose (symbol HT) is a measure of the radiation dose to tissue where an attempt has been made to allow for the different relative biological effects of different types of ionizing radiation. In quantitative terms, equivalent dose is less fundamental than absorbed dose, but it is more b...
Article
MR tagging
Cardiac MR tagging or myocardial tagging refers to an MRI-based acquisition method designed for the analysis of myocardial deformation.
Technique
The method exploits tissue magnetization as a tissue property. A local magnetic saturation grid of dark-lined tissue markers known as tags are induc...
Article
Dysgenesis of the corpus callosum
Dysgenesis of the corpus callosum may be complete (agenesis) or partial (dysgenesis) and represents an in utero developmental anomaly. It can be divided into:
primary agenesis: corpus callosum never forms
secondary dysgenesis: corpus callosum forms normally and is subsequently destroyed
Epide...
Article
Benign enhancing foramen magnum lesion
Benign enhancing foramen magnum lesions, also described as high signal lesions, are an incidental finding on 3D FLAIR MRI in a typical location in the foramen magnum just posterior to the intradural vertebral artery.
Epidemiology
The prevalence of this finding was 3% in a retrospective review...
Article
Myocardial infarction
Myocardial infarction (MI), colloquially known as a heart attack, an acute coronary syndrome, results from interruption of myocardial blood flow and resultant ischemia and is a leading cause of death worldwide.
Epidemiology
Risk factors
male > females
age
>45 years for males
>55 years for...
Article
Snowstorm sign (extracapsular breast implant rupture)
The snowstorm sign on breast ultrasound imaging represents the presence of free silicone droplets mixed with breast parenchymal tissue causing characteristic homogeneously hyperechoic dense shadowing with dispersion of the ultrasound beam. It is considered the most reliable sign of extracapsular...
Article
Lipomatous hypertrophy of the interatrial septum
Lipomatous hypertrophy of the interatrial septum is a relatively uncommon disorder of the heart characterized by benign fatty infiltration of the interatrial septum. It is commonly found in elderly and obese patients as an asymptomatic incidentally discovered finding.
Epidemiology
The prevale...
Article
Brachial plexus injuries
Brachial plexus injuries are a spectrum of upper limb neurological deficits secondary to partial or complete injury to the brachial plexus, which provides the nerve supply of upper limb muscles.
Clinical presentation
Trauma, usually by motor vehicle accidents, involves severe traction on the ...
Article
Vasa vasorum
The vasa vasorum represents the supporting microvasculature of the larger caliber arteries and veins of the body.
Gross anatomy
The vasa vasorum has two subtypes in humans 2,3:
arterial vasa vasorum: arises from various arteries based on anatomical location (e.g. intercostal arteries for desc...
Article
Cardiac CT
Computed tomography of the heart or cardiac CT is routinely performed to gain knowledge about cardiac or coronary anatomy, to detect or diagnose coronary artery disease (CAD), to evaluate patency of coronary artery bypass grafts or implanted coronary stents or to evaluate volumetry and cardiac f...
Article
Pulmonary artery catheter
Pulmonary artery catheters (PAC or Swan-Ganz catheters) are balloon flotation catheters that are inserted into the pulmonary arteries. They can be inserted simply, quickly, with little training and without fluoroscopic guidance at the bedside, even in the seriously ill patient.
Usage
Historica...
Article
Spinning top urethra
Spinning top urethra is non-obstructive posterior urethral dilatation seen on voiding cystourethrography, mainly in females. It was initially considered as an indicator of distal urethral narrowing/stenosis. However, it is now believed to be due to functional discoordinate voiding or bladder ins...
Article
Modic type endplate changes
Modic type endplate changes represent a classification for vertebral body endplate MRI signal changes, first described in 1988 1. It is widely recognized by radiologists and clinicians and is a useful shorthand for reporting MRIs of the spine.
Modic type 1 has received renewed attention due to ...
Article
Alpha angle (cam morphology)
The alpha angle is a radiological measurement proposed for the detection of cam morphology, which is sometimes associated with femoroacetabular impingement (FAI).
Terminology
The term alpha angle is also used in a separate and unrelated context in the evaluation of developmental dysplasia of ...
Article
Prostatic leiomyoma
Prostatic leiomyomas are benign mesenchymal tumors of the prostate.
Epidemiology
Prostatic leiomyomas are very rare 1-3.
Diagnosis
The diagnosis of prostatic leiomyoma is based on histology.
Clinical presentation
Prostatic leiomyomas can present with voiding difficulties or obstructive sym...
Article
Peroxisome biogenesis disorder
Peroxisome biogenesis disorders (PBDs) are autosomal recessive, inborn errors of peroxisomes, a eukaryotic cell organelle critical to the breakdown of very long chain fatty acids via beta-oxidation.
Terminology
The terminology has changed to "severe", "intermediate", and "mild" forms of Zellw...
Article
Popliteofibular ligament
The popliteofibular ligament (PFL) belongs to the lateral supporting structures of the knee and is one of the three primary stabilizers of the posterolateral corner 1-6.
Gross anatomy
It is a flattened, thick, and fan-shaped structure of the width of the popliteus muscle and two divisions 1. I...
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