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Open Directory Project - General - Pacemaker - Service and Support - Jobs pool - IR
 
Central Point ArtifactInfoSheet: - Artifacts -
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Please note that there are different common names for this artifact.
Artifact Information
NAME
Central point, DC artifact, DC offset
DESCRIPTION
Bright spot
REASON
DC voltage offset
HELP
Call the service
This artifact appears as a bright spot (or zipper line) in the image center. Central point artifacts are caused by a DC offset in the hardware. MRI scanners normally offer a software compensation (DC correction, baseline correction) for prevention.
mri safety guidance
Image Guidance
Take care for a constant temperature. If the problem increases or keeps on existing, it should be addressed to the service.
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• View the DATABASE results for 'Central Point Artifact' (4).Open this link in a new window

 
Further Reading:
  Basics:
Central Point Artifact
   by www.mritutor.org    
  News & More:
MRI Artifact Gallery
   by chickscope.beckman.uiuc.edu    
Cerebro Spinal Fluid Pulsation ArtifactInfoSheet: - Artifacts -
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Artifact Information
NAME
Cerebro spinal fluid pulsation
DESCRIPTION
Ghosting
REASON
Inconsistencies in phase and amplitude
Pulsatile cerebro spinal fluid flow produces ghost artifacts that are superimposed in the image.
mri safety guidance
Image Guidance
Flow compensation should be used to reduce these artifacts. This applies an additional gradient to eliminate phase differences for both stationary and moving spins at the echo time. At TE no phase differences is measured. If flow compensation is applied and there are still flow artifacts, cardiac triggering is an additional option to reduce these artifacts.
See also Motion Artifact.
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• View the DATABASE results for 'Cerebro Spinal Fluid Pulsation Artifact' (3).Open this link in a new window

MRI Resources 
Calculation - Bioinformatics - Case Studies - General - Brain MRI - Hospitals
 
Cervical Spine MRI
 
Cervical spine MRI is a suitable tool in the assessment of all cervical spine (vertebrae C1 - C7) segments (computed tomography (CT) images may be unsatisfactory close to the thoracic spine due to shoulder artifacts). The cervical spine is particularly susceptible to degenerative problems caused by the complex anatomy and its large range of motion.
Advantages of magnetic resonance imaging MRI are the high soft tissue contrast (particularly important in diagnostics of the spinal cord), the ability to display the entire spine in sagittal views and the capacity of 3D visualization. Magnetic resonance myelography is a useful supplement to conventional MRI examinations in the investigation of cervical stenosis. Myelographic sequences result in MR images with high contrast that are similar in appearance to conventional myelograms. Additionally, open MRI studies provide the possibility of weight-bearing MRI scan to evaluate structural positional and kinetic changes of the cervical spine.
Indications of cervical spine MRI scans include the assessment of soft disc herniations, suspicion of disc hernia recurrence after operation, cervical spondylosis, osteophytes, joint arthrosis, spinal canal lesions (tumors, multiple sclerosis, etc.), bone diseases (infection, inflammation, tumoral infiltration) and paravertebral spaces.
State-of-the-art phased array spine coils and high performance MRI machines provide high image quality and short scan time. Imaging protocols for the cervical spine includes sagittal T1 weighted and T2 weighted sequences with 3-4 mm slice thickness and axial slices; usually contiguous from C2 through T1. Additionally, T2 fat suppressed and T1 post contrast images are often useful in spine imaging.

See also Lumbar Spine MRI.
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• View the NEWS results for 'Cervical Spine MRI' (1).Open this link in a new window.

• View the DATABASE results for 'Cervical Spine MRI' (2).Open this link in a new window

 
Further Reading:
  News & More:
Ultrafast MRI protocol reduces scan time by 10 minutes for cervical imaging
Monday, 26 September 2022   by healthimaging.com    
In Vivo 3-D Cervical Spine Kinematics Demonstrated
Thursday, 19 May 2011   by www.doctorslounge.com    
MRI Images at a 45-Degree Angle Through The Cervic al Neural Forami na:A Technique For Improved Visualization(.pdf)
2006   by www.painphysicianjournal.com    
ChelateInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
A chelate is a heterocyclic chemical compound whose molecules consist of a metal ion attached by coordinate bonds to at least two nonmetal ions. The parent organic compound is known as a chelating agent - for example, DTPA (diethylenetriaminepentaacetic acid) used in contrast agents. Chelates are used in analytical chemistry, in agriculture as carriers of essential trace metals, in water softening, and to remove an excess of iron, which may build up to toxic levels in the body. Metalloproteins may influence the performance of enzymes or provide a mechanism for the storage of iron in the spleen and plasma of the human body.
Paramagnetic metal ions such as gadolinium improve the MRI signal, but the toxicity of these uncomplexed metal ions makes the use of a chelate to bind the metal ion essential. The chelated metal ion could be safely excreted.
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• View the NEWS results for 'Chelate' (4).Open this link in a new window.

• View the DATABASE results for 'Chelate' (34).Open this link in a new window

 
Further Reading:
  Basics:
Definition of chelate - WordReference.com Dictionary
   by www.wordreference.com    
  News & More:
Tumor-targeted MR Contrast Agents: Hype or Future Hope?
November 2004   by radiology.rsnajnls.org    
Spurious Hypocalcemia After Omniscan- or OptiMARK-Enhanced Magnetic Resonance Imaging: An Algorithm for Minimizing a False-Positive Laboratory Value
October 2004   by www.findarticles.com    
Multimodal Nanoparticles for Quantitative Imaging(.pdf)
Tuesday, 13 December 2011   by alexandria.tue.nl    
Chemical Shift
 
Chemical shift depends on the nucleus and its environment and is defined as nuclear shielding / applied magnetic field. Nuclei are shielded by a small magnetic field caused by circulating electrons, termed nuclear shielding. The strength of the shield depends on the different molecular environment in that the nucleus is embedded. Nuclear shielding is the difference between the magnetic field at the nucleus and the applied magnetic field.
Chemical shift is measured in parts per million (ppm) of the resonance frequency relative to another or a standard resonance frequency.
The major part of the MR signal comes from hydrogen protons; lipid protons contribute a minor part. The chemical shift between water and fat nuclei is about 3.5 ppm (~220 Hz; 1.5T). Through this difference in resonance frequency between water and fat protons at the same location, a misregistration (dislocation) by the Fourier Transformation take place, when converting MR signals from frequency to spatial domain. This effect is called chemical shift artifact or chemical shift misregistration artifact.
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• View the DATABASE results for 'Chemical Shift' (29).Open this link in a new window

 
Further Reading:
  Basics:
FUNDAMENTALS OF MRI: Part III – Forming an MR Image
   by www.e-radiography.net    
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by www.ajronline.org    
MRI Resources 
Crystallography - Non-English - RIS - Safety Training - General - Breast Implant
 
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