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Result : Searchterm 'Motion Artifact' found in 5 terms [] and 19 definitions []
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Searchterm 'Motion Artifact' was also found in the following services: 
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Resources  (1)  
 
Ghosting ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Artifact Information
NAME
Ghosting, ghost
DESCRIPTION
Displaced reduplications of image in phase encoding direction
REASON
Motion, heartbeat, respiration
HELP
Triggering, breath hold, pharmaceuticals to reduce bowel motion
Ghosting artifacts are in the most cases caused by movements (e.g., respiratory motion, bowel motion, arterial pulsations, swallowing, and heartbeat) and appear in the phase encoding direction.
mri safety guidance
Image Guidance
Ghosting artifacts can be reduced by respiratory and cardiac triggering, the use of breath holding pulse sequences, flow compensation or presaturation pulses, depending on their origin. To reduce bowel motion also pharmaceuticals, such as glucagon or scopolamine are useful. This will decrease artifacts from both peristalsis and breathing.

See also Motion Artifact, Phase Encoded Motion Artifact, Cardiac Motion Artifact, and Artifact Reduction - Motion.
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Further Reading:
  Basics:
MRI Artifact Gallery
   by chickscope.beckman.uiuc.edu    
Searchterm 'Motion Artifact' was also found in the following service: 
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Radiology  (2) Open this link in a new window
Artifact by Patient MovementInfoSheet: - 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
Motion, movement
DESCRIPTION
Blurring, ghosting
REASON
Patient movement
HELP
Fast scan techniques
Patient movement during the scans are often an imaging problem. Artifacts from patient movement are widely varied due to a dependence when during k-space filling the motion occurs. When the patient moving causes only in the last few seconds of the scan at that time the outside edges of K-space were being filled, and as a result the artifact does not overly affect the image (there are only fine lines).
image guidance
Image Guidance
A good cooperation between the patient and the operator is the best way to avoid these artifacts, in difficult cases a sedative may help. If a compliance of the patient is not possible (e.g. pain, stroke, or consciousness), choose fast scan methods like gradient echo or single shot technique.

See also Motion Artifact and Phase Encoded Motion Artifact.
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Further Reading:
  News & More:
Patient movement during MRI: Additional points to ponder
Tuesday, 5 January 2016   by www.healthimaging.com    
MRI results affected by movement? MIT researchers have an AI-powered solution
Friday, 25 August 2023   by healthimaging.com    
MRI Resources 
Breast MRI - Intraoperative MRI - Image Quality - MRI Technician and Technologist Jobs - Open Directory Project - Stent
 
Gradient Motion Rephasing
 
(GMR) The application of strategic gradient pulses can compensate the objectionable spin phase effects of flow motion. That means the reducing of flow effects, e.g. gradient moment nulling of the first order of flow. The simplest velocity-compensated pulse sequence is the symmetrical second echo of a spin echo pulse sequence.
Gradient field changes can be configured in such a way that during an echo the magnetization signal vectors for all pixels have zero phase angle independent of velocities, accelerations etc. of the measured tissue. E.g. the adjustment to zero at the time TE of the net moments of the amplitude of the waveform of the magnetic field gradients with time. The zeroth moment is the area under the curve, the first moment is the 'center of gravity' etc. The aim is to minimize the phase shifts acquired by the transverse magnetization of excited nuclei moving along the gradients (including the effect of refocusing RF pulses), particularly for the reduction of image artifacts due to motion.
Also called Flow Compensation (FC), Motion Artifact Suppression Technique (MAST), Flow motion compression (STILL), Gradient Rephasing (GR), Shimadzu Motion Artifact Reduction Technique (SMART).
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• View the DATABASE results for 'Gradient Motion Rephasing' (2).Open this link in a new window

 
Further Reading:
  Basics:
Motion Compensation in MR Imaging
   by ccn.ucla.edu    
Searchterm 'Motion Artifact' was also found in the following services: 
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Resources  (1)  
 
Lung ImagingMRI Resource Directory:
 - Lung Imaging -
 
Lung imaging is furthermore a challenge in MRI because of the predominance of air within the lungs and associated susceptibility issues as well as low signal to noise of the inflated lung parenchyma. Cardiac and respiratory triggered or breath hold sequences allow diagnostic imaging, however a comparable image quality with computed tomography is still difficult to achieve.
Assumptions for lung MRI:
•
Low signal to noise ratio of the inherently low lung proton density.
•
Cardiac and respiratory motion artifacts.
•
Magnetic susceptibility effects of large magnetic field gradients.
•
Very short transverse relaxation times and significant diffusion yielding short T2 (30-70 msec), short T2* (1-3 msec), and additional long T1 relaxation times (1300-1500 msec).
•
The extreme short T2 values are responsible for a fast signal decay during a single shot readout, resulting in blurring.

The current trends in MRI are the use of new imaging technologies and increasingly powerful magnetic fields. Among these technologies are parallel imaging techniques as well as ventilation agents like hyperpolarized helium for the use as an inert inhalational contrast agent to study lung ventilation properties. With hyperpolarized gases clear images of the lungs can be obtained without using a large magnetic field (see also back projection imaging). Single shot sequences (e.g. TSE or Half Fourier Acquisition Single Shot Turbo Spin Echo HASTE) used in lung MR imaging benefits from parallel imaging techniques due to reduced relaxation time effects during the echo train and therefore reduced image blurring as well as reduced motion artifacts.
In the future, more effective contrast agents may provide an alternative solution to the need for high field MRI. Dynamic contrast enhanced MRI perfusion has demonstrated a potential in the diagnosis of pulmonary embolism or to characterize lung cancer and mediastinal tumors. 3D contrast enhanced magnetic resonance angiography of the thoracic vessel.

See also the related poll result: 'MRI will have replaced 50% of x-ray exams by'
 
Images, Movies, Sliders:
 Anatomic Imaging of the Lungs  Open this link in a new window
      

Courtesy of  Robert R. Edelman
 Normal Lung Gd Perfusion MRI  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 MRI Thorax Basal Plane  Open this link in a new window
 
Radiology-tip.comradLung Scintigraphy
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• View the DATABASE results for 'Lung Imaging' (7).Open this link in a new window


• View the NEWS results for 'Lung Imaging' (3).Open this link in a new window.
 
Further Reading:
  Basics:
A safer approach for diagnostic medical imaging
Monday, 29 September 2014   by www.eurekalert.org    
Parallel Lung Imaging(.pdf)
  News & More:
Chest MRI a viable alternative to chest CT in COVID-19 pneumonia follow-up
Monday, 21 September 2020   by www.healthimaging.com    
CT Imaging Features of 2019 Novel Corona virus (2019-nCoV)
Tuesday, 4 February 2020   by pubs.rsna.org    
Polarean Imaging Phase III Trial Results Point to Potential Improvements in Lung Imaging
Wednesday, 29 January 2020   by www.diagnosticimaging.com    
Low Power MRI Helps Image Lungs, Brings Costs Down
Thursday, 10 October 2019   by www.medgadget.com    
Chest MRI Using Multivane-XD, a Novel T2-Weighted Free Breathing MR Sequence
Thursday, 11 July 2019   by www.sciencedirect.co    
Researchers Review Importance of Non-Invasive Imaging in Diagnosis and Management of PAH
Wednesday, 11 March 2015   by lungdiseasenews.com    
New MRI Approach Reveals Bronchiectasis' Key Features Within the Lung
Thursday, 13 November 2014   by lungdiseasenews.com    
MRI techniques improve pulmonary embolism detection
Monday, 19 March 2012   by medicalxpress.com    
  News & More:
Partnership with VIDA to streamline adoption of advanced MRI of the lungs
Monday, 11 September 2023   by www.itnonline.com    
Searchterm 'Motion Artifact' was also found in the following service: 
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Radiology  (2) Open this link in a new window
Respiratory Compensation
 
Respiratory compensation reduces motion artifacts due to breathing. The approach is to reassign the echoes that are sensitive to respiratory motion in the central region of k-space. The outer lines of phase encoding normally contain the echoes where the motion from expiration is the greatest. The central portion of k-space will have encoded the echoes where inspiration and expiration are minimal. By a bellows device fixed to the abdomen, monitoring of the diaphragm excursion is possible. Respiratory compensation does not increase scan time with most systems.
An advantage of very fast sequences is the possibility of breath holding during the acquisition to eliminate motion artifacts. Breath hold is commonly used on most abdominal studies where images are acquired using gradient echo-based sequences during a brief inspiratory period (20-30 seconds). To enhance the breath holding endurance of the patient, connecting the patient to oxygen at a 1-liter flow rate via a nasal cannula has been shown to be helpful.
Also called PEAR, Respiratory Trigger, Respiratory Gating, PRIZE, FREEZE, Phase Reordering.

See also Phase Encoding Artifact Reduction, Respiratory Ordered Phase Encoding.
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• View the DATABASE results for 'Respiratory Compensation' (4).Open this link in a new window

 
Further Reading:
  News & More:
Controlling patient's breathing makes cardiac MRI more accurate
Friday, 13 May 2016   by www.upi.com    
MRI Resources 
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