Items tagged “mri”

785 results found
Article

Bright rim sign (DNET)

The bright rim sign, also known as the hyperintense ring sign, is an MRI sign described most frequently in dysembryoplastic neuroepithelial tumors (DNET) but is also seen in some other tumors. Terminology Although the sign is most associated with DNETs, and should probably be reserved in case...
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

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

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

Phase-encoded motion artifact

Phase-encoded motion artifact is one of many MRI artifacts occurring as a result of tissue/fluid moving during the scan. It manifests as ghosting in the direction of phase-encoding, usually in the direction of the short axis of the image (i.e left to right on axial or coronal brains, and anterio...
Article

Sugar coating

So-called "sugar coating" or zuckerguss (German for sugar icing) refers to the appearance of diffuse linear/sheetlike leptomeningeal contrast enhancement in the brain or spinal cord due to drop metastases or leptomeningeal carcinomatosis. It is seen both as a result of CNS involvement from dista...
Case

Baastrup syndrome

  Diagnosis certain
Frank Gaillard
Published 07 May 2008
53% complete
MRI
Case

Chiari I malformation

  Diagnosis certain
Frank Gaillard
Published 07 May 2008
68% complete
MRI
Case

Central pontine myelinolysis

  Diagnosis possible
Frank Gaillard
Published 07 May 2008
53% complete
MRI
Case

Foraminal lumbar disc protrusion

  Diagnosis certain
Frank Gaillard
Published 07 May 2008
80% complete
MRI
Case

Leptomeningeal lymphoma

  Diagnosis certain
Frank Gaillard
Published 07 May 2008
77% complete
MRI
Case

Quadriceps tendon rupture

  Diagnosis certain
Frank Gaillard
Published 07 May 2008
71% complete
MRI
Case

Papilledema (MRI)

  Diagnosis probable
Frank Gaillard
Published 07 May 2008
39% complete
MRI
Case

Phase mismapping

  Diagnosis not applicable
Frank Gaillard
Published 07 May 2008
45% complete
MRI
Case

Weber syndrome

  Diagnosis almost certain
Frank Gaillard
Published 07 May 2008
71% complete
MRI
Article

Anterior cruciate ligament mucoid degeneration

Anterior cruciate ligament (ACL) mucoid degeneration, along with tears and anterior cruciate ligament ganglion cysts, is a relatively common cause of increased signal within the anterior cruciate ligament (ACL). The appearance can mimic acute or chronic interstitial partial tears of the ACL. How...
Case

Recurrent astrocytoma (MR perfusion)

  Diagnosis almost certain
Frank Gaillard
Published 19 Dec 2008
74% complete
MRI
Article

Normal myelination

After normal myelination in utero, myelination of the neonatal brain is far from complete. The first myelination is seen as early as the 16th week of gestation, in the column of Burdach, but only really takes off from the 24th week 1. It does not reach maturity until 2 years or so. It correlates...
Article

T1 weighted image

T1 weighted image (also referred to as T1WI or the "spin-lattice" relaxation time) is one of the basic pulse sequences in MRI and demonstrates differences in the T1 relaxation times of tissues. A T1WI relies upon the longitudinal relaxation of a tissue's net magnetization vector (NMV). Basicall...
Article

B0

The B0 in MRI refers to the main static magnetic field and is measured in teslas (T). The majority of MRI systems in clinical use are 1.5 T, with increasing numbers of 3 T systems being installed. Since 2017, 7 T clinical scanners have been available, see ultrahigh field MRI. Altering the field...