Items tagged “mri”

679 results found
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

Bright rim sign in DNETs

The bright rim sign has been described in DNETs and is seen, as the name so aptly describes, as a rim of high signal around the DNET on FLAIR sequences.
Case

Quadriceps tendon rupture

T1WI sagittal
 Diagnosis certain
A.Prof Frank Gaillard
Published 07 May 2008
80% complete
MRI
Case

Weber syndrome

 Diagnosis almost certain
A.Prof Frank Gaillard
Published 07 May 2008
62% complete
MRI
Article

Nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF), also known as nephrogenic fibrosing dermopathy, is a complication of gadolinium-based contrast agents used in imaging studies. It is characterised by "firm, erythematous, and indurated plaques of the skin associated with subcutaneous oedema" 1. Eventually, f...
Case

Central pontine myelinolysis

 Diagnosis probable
A.Prof Frank Gaillard
Published 07 May 2008
59% complete
MRI
Case

Baastrup syndrome

 Diagnosis certain
A.Prof Frank Gaillard
Published 07 May 2008
62% complete
MRI
Case

Chiari 1 malformation

 Diagnosis certain
A.Prof Frank Gaillard
Published 07 May 2008
62% complete
MRI
Case

Leptomeningeal lymphoma

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

Papilloedema (MRI)

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

Phase mismapping

T1WI annotated

W...
 Diagnosis not applicable
A.Prof Frank Gaillard
Published 07 May 2008
45% complete
MRI
Article

Magic angle effect (MRI artifact)

The magic angle is an MRI artifact which occurs on sequences with a short TE (less than 32ms; T1W sequences, PD 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 hyperintense, thus potentially be...
Case

Recurrent astrocytoma - MR perfusion

Perfusion 1
 Diagnosis almost certain
A.Prof Frank Gaillard
Published 19 Dec 2008
47% complete
MRI
Article

Chemical shift artifact

Chemical shift artefact or misregistration is a type of MRI artifact. It is a common finding on some MRI sequences, and used in MRS. Chemical shift is due to the differences between resonance frequencies of fat and water. It occurs in the frequency encode direction where a shift in the detected...
Case

Foraminal lumbar disc protrusion

 Diagnosis certain
A.Prof Frank Gaillard
Published 07 May 2008
74% complete
MRI
Article

B0

The B0 in MRI refers to the main static magnetic field and is measured in teslas. The majority of MRI systems in clinical use are 1.5T, with increasing numbers of 3T systems being installed. Altering the field strength will affect the Larmor frequency at which the protons precess. See also 1....
Article

Sugar coating

The so-called "sugar coating" or zuckerguss (German for sugar icing) is seen in post-contrast images of the brain and spinal cord in patients with leptomeningeal drop metastases or leptomeningeal carcinomatosis. It is seen both as a result of CNS involvement from distant primaries as well as dir...
Article

T1 weighted image

T1 weighted image (also referred to as T1WI or "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 magnetisation vector (NMV). Basically, s...
Article

1.5T vs 3T

Comparing 1.5T vs 3T MRI systems identifies a number of differences; a 3T system has increased signal to noise ratio (SNR) increased spatial resolution increased temporal resolution increased specific absorption rate (SAR) increased acoustic noise Signal to noise ratio Theoretically, sign...
Article

Rectal cancer (staging)

Staging strongly influences the success of, and rate of local recurrence following rectal cancer resection. In rectal cancer, pre-treatment MRI is the evaluation of choice, guiding surgical and non-surgical management options.  TNM staging See: TNM staging system for a general description. Pr...

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