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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

28 results found
Article

CT elbow (protocol)

The CT elbow protocol serves as an examination for the bony assessment of the elbow and is usually performed as a non-contrast study. It can be also combined with a CT arthrogram for the evaluation of chondral and osteochondral injuries.  Note: This article aims to frame a general concept of a ...
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

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

CT thoracic spine (protocol)

The CT thoracic spine or T-spine protocol serves as an examination for the assessment of the thoracic spine. As a separate examination, it is often performed as a non-contrast study. It might be combined or simultaneously acquired with a CT chest or CT chest-abdomen-pelvis as part of a trauma or...
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

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....
Article

CT shoulder (protocol)

The CT shoulder protocol serves as an examination for the assessment of the shoulder joint. It is often performed as a non-contrast study. It can be combined with a CT arthrogram for the evaluation of labral injuries or the rotator cuff if MRI is contraindicated or in a postoperative setting whe...
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

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

Wrist protocol (MRI)

The MRI wrist protocol encompasses a set of MRI sequences for the routine assessment of the wrist joint. Note: This article aims to frame a general concept of an MRI protocol for the assessment of the wrist. Protocol specifics will vary depending on MRI scanner type, specific hardware and softw...
Article

Ankle protocol (MRI)

The MRI ankle protocol encompasses a set of MRI sequences for the routine assessment of the ankle joint. Note: This article aims to frame a general concept of an MRI protocol for the assessment of the ankle. Protocol specifics will vary depending on MRI scanner type, specific hardware and softw...
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

Hip protocol (MRI)

The MRI hip protocol encompasses a set of different MRI sequences for the routine assessment of the single hip joint. Note: This article aims to frame a general concept of an MRI protocol for the assessment of a single hip joint. Protocol specifics will vary depending on MRI scanner type, speci...
Article

Shoulder protocol (MRI)

The MRI shoulder protocol encompasses a set of different MRI sequences for the routine assessment of the shoulder joint. Note: This article aims to frame a general concept of an MRI protocol for the assessment of the shoulder joint. Protocol specifics will vary depending on MRI scanner type, sp...
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

Ultrasound elastography

Ultrasound elastography, also called as sono-elastography, is a modern evolutionary method of sonographic imaging. Techniques include shear wave elastography (also known as transient elastography) and strain elastography (also known as static or compression elastography). These techniques utiliz...
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. Until recently purely a research tool, following the introduction of the first 7 T clinical scanner in 2017, there are now a slowly increasin...
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

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

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

Anisotropy

Anisotropy is an artifact encountered in ultrasound, notably in muscles and tendons during a musculoskeletal ultrasound. In musculoskeletal applications, the artifact may prompt an incorrect diagnosis of tendinosis or tendon tear. When the ultrasound beam is incident on a fibrillar structure su...
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

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

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

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 administration of gadolinium-based contrast agents (GBCAs) used in MRI.  The American College of Radiology (ACR) has divided ga...
Article

Magic angle effect (MRI artifact)

The magic angle is an MRI artifact which occurs on sequences with a short TE (less than 32ms; T1 weighted sequences, proton density weighted sequences and gradient echo sequences).  It is confined to regions of tightly bound collagen at 54.74° from the main magnetic field (B0), and appears hype...
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 MRS. This artifact occurs in the frequency-encoding direction and is due to spatial misregistration of fat and water molecules.  Chemical shift is due to the difference...

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