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.
715 results found
Article
Contrast-enhanced ultrasound
Contrast-enhanced ultrasound (CEUS) involves the administration of intravenous contrast agents consisting of microbubbles/nanobubbles of gas.
Uses
liver
hepatic metastasis
cystadenoma/cystadenocarcinoma
cholangiocarcinoma
hepatocellular carcinoma
hepatic adenoma
focal nodular hyperplasia...
Article
Stochastic effects
Stochastic effects occur by chance and can be compared to deterministic effects which result in a direct effect. Cancer induction and radiation induced hereditary effects are the two main examples of stochastic effects.
Models
Cancer induction as a result of exposure to radiation is thought by...
Article
Dose length product
Dose length product (DLP) is a measure of CT tube radiation output/exposure (measured in mGy.cm). It is related to volume CT dose index (CTDIvol), but CTDIvol represents the dose through a slice of an appropriate phantom. The dose length product accounts for the length of radiation output along ...
Article
k-space
k-space is an abstract concept and refers to a data matrix containing the raw MRI data. This data is subjected to mathematical function or formula called a transform to generate the final image. A discrete Fourier or fast Fourier transform 1-3 is generally used, though other transforms such as t...
Article
CheckList for EvaluAtion of Radiomics research (CLEAR)
The CheckList for Evaluation of Radiomics Research (CLEAR) is a 58-item reporting guideline designed specifically for radiomics. It aims to improve the quality of reporting in radiomics research 1. CLEAR is endorsed by the European Society of Radiology (ESR) and the European Society of Medical I...
Article
Radiomics quality score
The radiomics quality score (RQS) assesses the characteristics and, ultimately, the quality of a radiomics study, including its reporting. The score has thirty-six potential points given based on sixteen criteria, with a score of thirty-six indicating superlative quality. The criteria emphasize ...
Article
Cobalt
Cobalt (chemical symbol Co) is an essential trace element. Its most important function in humans is as the active metal atomic center of vitamin B12.
Chemistry
Basic chemistry
Cobalt is a shiny grey-silvery transition metal with an atomic number 27 and an atomic weight of 58.93 Daltons (Da). ...
Article
Emerging medical imaging technologies
This article is a summary of emerging medical imaging technologies in development or in the early phase of clinical adoption. The methods are listed by modality.
Radiography
dark-field radiography
x-ray phase-contrast imaging
CT
dark-field CT
deep-learning reconstruction
photon counting ...
Article
Reflection
Reflection of a sound wave occurs when the wave passes between two tissues of different acoustic impedances and a fraction of the wave 'bounces' back. This forms one of the major principles of ultrasound imaging as the ultrasound probe detects these reflected waves to form the desired image.
An...
Article
Photon-counting computed tomography
Photon-counting computed tomography (PCCT) is a new technology in CT that could represent the next major technological milestone in the field. Briefly, photon-counting CT uses energy-resolving detectors, thereby enabling scanning at multiple energies.
Technique
Physical principles
Current cli...
Article
Spatial resolution (CT)
Spatial resolution in CT is the ability to distinguish between objects or structures that differ in density.
A high spatial resolution is important for one to discriminate between structures that are located within a small proximity to each other.
Factors affecting CT spatial resolution
fiel...
Article
Short tau inversion recovery
Short tau inversion recovery (STIR), also known as short TI inversion recovery, is a fat suppression technique with an inversion time TI = ln(2)·T1fat, where the signal of fat is zero. This equates to approximately 140 ms at 1.5 T.
To distinguish two tissue components with this technique, their...
Article
Slip-ring (CT)
Slip-ring functions to allow the transfer of electrical information and power between a rotating device and external components. They are used in helical CT and MRI scanners among other applications; in this setting, they allow image acquisition without progressive twisting of cables as the scan...
Article
Cardiac strain imaging
Strain imaging is a cardiac imaging technique that detects ventricular deformation patterns and functional abnormalities before they become obvious as regional wall motion abnormalities on conventional cine imaging or echo. It has become more popular lately due to several technological improveme...
Article
Dark-field radiography
Dark-field radiography is an emerging medical imaging technology. While conventional x-ray imaging is based on the differential attenuation of various organs and tissues, dark-field radiography utilizes ultra-small angle x-ray scattering similar to dark-field computed tomography.
Clinical appli...
Article
Elastography
Elastography is a newer technique that exploits the fact that a pathological process alters the elastic properties of the involved tissue. This change in elasticity is detected and imaged using elastography.
Radiographic technique
Sono-elastography
Sono-elastography is the term used when ultr...
Article
Iterative reconstruction (CT)
Iterative reconstruction refers to an image reconstruction algorithm used in CT that begins with an image assumption and compares it to real-time measured values while making constant adjustments until the two are in agreement.
Computer technology limited early scanners in their ability to perf...
Article
Virtual grid
Virtual grid software is a relatively new innovation utilizing no physical grid at all. Instead, the original purpose of a grid is replicated by an algorithm 1 based on fundamental mathematics (i.e. Laplace transformation, wavelet transformation and Gaussian decomposition) which iteratively reco...
Article
Dual energy CT
Dual energy CT, also known as spectral CT, is a computed tomography technique that uses two separate x-ray photon energy spectra, allowing the interrogation of materials that have different attenuation properties at different energies.
Technique
Whereas conventional single-energy CT produces a...
Article
T1 mapping - myocardium
T1 mapping is a magnetic resonance imaging technique used to calculate the T1 time of a certain tissue and display them voxel-vice on a parametric map. It has been used for myocardial tissue characterization 1-6 and has been investigated for other tissues 5.
Terminology
Native T1 is referred t...
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