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.
29 results found
Article
Brown adipose tissue
Brown adipose tissue (BAT) (also known as brown fat) is one of two types of adipose tissue (the other one being white fat) important for producing thermal energy (heat, non-shivering thermogenesis), especially in the newborn. It constitutes ~5% of body mass in the newborn and tends to reduce mar...
Article
Magnetic resonance neurography
Magnetic resonance neurography (MRN) is a relatively new non-invasive imaging technique for dedicated assessment of peripheral nerves.
It is used to assess peripheral nerve entrapments and impingements as well as localization and grading of nerve injuries and lesions.
Dedicated high-resolution...
Article
Nephrogenic systemic fibrosis
Nephrogenic systemic fibrosis (NSF), also known as nephrogenic fibrosing dermopathy, occurs almost exclusively in patients with renal impairment and is associated with the administration of gadolinium-based contrast agents (GBCAs) used in MRI.
The American College of Radiology (ACR) has divide...
Article
CT pelvis (protocol)
The CT pelvis protocol serves as an outline for the acquisition of a pelvic CT. As a separate examination, it might be performed as a non-contrast or contrast study or might be combined with a CT hip or rarely with a CT cystogram. A pelvic CT might be also conducted as a part of other scans such...
Article
FABS position
The FABS position relates to MRI elbow examinations for improved visualization of the distal biceps brachii tendon insertion and is a mnemonic for elbow flexed, shoulder abducted and forearm supinated.
Article
Metal artifact reduction sequence
A metal artifact reduction sequence (MARS) is intended to reduce the size and intensity of susceptibility artifacts resulting from magnetic field distortion.
A variety of techniques are used for reducing metal artifacts at MRI, both for addressing artifacts due to the presence of metal in the i...
Article
dGEMRIC (delayed gadolinium-enhanced MRI of cartilage)
dGEMRIC, or delayed gadolinium-enhanced MRI of cartilage is a technique that can be used quantitatively to assess glycosaminoglycan content of cartilage or qualitatively to asses the overall structures of cartilage. The dGEMRIC protocol consists of a T1-mapping sequence. When the technique is ad...
Article
Ultrahigh field MRI
Ultrahigh field (UHF) magnetic resonance imaging refers to imaging done on any MRI scanner with a main magnetic field (B0) strength of 7 tesla or greater. The first 7 T clinical scanner was introduced in 2017, and there are an ever increasing number of academic centers worldwide with ultrahigh f...
Article
T1 rho
T1 rho, also known as T1ρ or "spin lock" ('ρ' is the symbol for the Greek letter rho), is an MRI sequence that is being developed for use in musculoskeletal imaging. At the moment it is mostly investigational and does not yet have widespread clinical use.
The "rho" in the sequence name refers t...
Article
Chemical shift artifact
Chemical shift artifact or misregistration is a type of MRI artifact. It is a common finding on some MRI sequences and used in magnetic resonance spectroscopy (MRS). This artifact occurs in the frequency-encoding direction and is due to spatial misregistration of fat and water molecules.
Chemi...
Article
CT foot (protocol)
The CT foot protocol serves as an examination for the bony assessment of the fore and mid-foot and is almost always performed as a non-contrast study. It can also be combined with a CT ankle protocol or can be acquired as dual-energy CT depending on the clinical question.
Note: This article aim...
Article
CT hand and wrist (protocol)
The CT hand and wrist protocol serves as an examination for the bony assessment of the wrist and is often performed as a non-contrast study and less often as a contrast-enhanced study. A CT wrist can be also conducted as a CT arthrogram for the evaluation of ligamentous injuries and the triangul...
Article
Elbow protocol (MRI)
The MRI elbow protocol encompasses a set of different MRI sequences for the routine assessment of the elbow joint.
Note: This article aims to frame a general concept of an MRI protocol for the assessment of the elbow joint. Protocol specifics will vary depending on MRI scanner type, specific h...
Article
Technetium 99m-methyl diphosphonate
Technetium 99m-methyl diphosphonate (99mTc MDP) is a radiotracer used in nuclear medicine especially for bone scintigraphy. Any disease process which results in extracellular fluid expansion will lead to accumulation of this tracer.
Radionuclide profile
photon energy: 140 keV
physical half-li...
Article
Quantitative computed tomography (bone)
Quantitative computed tomography (QCT) in bone imaging is a bone mineral density (BMD) measurement technique in which the CT scanner is calibrated using solid phantoms (made of calcium hydroxyapatite, representing various bone mineral densities) placed under the patient in a pad. With this calib...
Article
Intermediate weighted images
An intermediate weighted image is acquired by a sequence with a proton-density like long repetition time and a prolonged echo time usually 35-60 ms 1,2. It combines the ability to depict the detailed anatomy of a proton density-weighted image with the fluid sensitivity of a T2-weighted sequence,...
Article
CT lumbar spine (protocol)
The CT lumbar spine or L-spine protocol serves as an examination for the assessment of the lumbar spine. As a separate examination, it is most often performed as a non-contrast study. It might be combined or simultaneously acquired with a CT abdomen. It also forms a part of a polytrauma CT or mi...
Article
Magic angle effect (MRI artifact)
The magic angle is an MRI artifact that occurs in sequences with a short TE (less than 32 ms) - T1 weighted, proton density weighted, and gradient echo sequences.
It is confined to regions of tightly bound collagen at 54.74° from the main magnetic field (B0), and appears hyperintense, thus pote...
Article
Fat suppressed imaging
Fat suppression is commonly used in magnetic resonance imaging (MRI) imaging to suppress the signal from adipose tissue or detect adipose tissue 1. It can be applied to both T1 and T2 weighted sequences.
Due to short relaxation times, fat has a high signal on MRI. This high, easily recognized ...
Article
CT cervical spine (protocol)
The CT cervical spine or C-spine protocol serves as an examination for the assessment of the cervical spine. It is usually performed as a non-contrast study. In certain situations, it might be combined or simultaneously acquired with a CT angiography of the cerebral arteries or a CT of the neck....
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