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Respiratory Trigger
 
Respiratory triggering is a type of respiratory motion commonly used with fast imaging techniques. Images are acquired during the expiration phase. With this type of technique, the scan time is based on the selected TR per respiratory cycle and the patient's breathing patterns.
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Further Reading:
  News & More:
Controlling patient's breathing makes cardiac MRI more accurate
Friday, 13 May 2016   by www.upi.com    
MRI Resources 
Blood Flow Imaging - Intraoperative MRI - MRI Training Courses - Mobile MRI - Pregnancy - Brain MRI
 
Cardiac Motion ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Artifact Information
NAME
Cardiac motion
DESCRIPTION
Blurring, ghosting
REASON
Cardiac motion
HELP
cardiac and respiratory synchronization
Movement of the heart causes blurring and ghosting in the images. The artifacts appear in the phase encoding direction, independent of the direction of the motion.
mri safety guidance
Image Guidance
These artifacts can be reduced by using cardiac synchronization: triggering, gating or retrospective triggering. Maximum reduction can be achieved by using triggering in combination with flow compensation, respiratory triggering or breath hold and regional saturation techniques.

See also Motion Artifact.
 
Images, Movies, Sliders:
 Cardiac Infarct Short Axis Cine bFFE 1  Open this link in a new window
    
 Normal Dual Inversion Fast Spin-echo  Open this link in a new window
 
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• View the DATABASE results for 'Cardiac Motion Artifact' (2).Open this link in a new window

 
Further Reading:
  Basics:
Motion-compensation of Cardiac Perfusion MRI using a Statistical Texture Ensemble(.pdf)
June 2003   by www.imm.dtu.dk    
  News & More:
Controlling patient's breathing makes cardiac MRI more accurate
Friday, 13 May 2016   by www.upi.com    
MRI Resources 
Stent - MRI Technician and Technologist Career - Equipment - Bioinformatics - Implant and Prosthesis - Calculation
 
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    
MRI Resources 
Knee MRI - MRI Physics - Liver Imaging - MRI Centers - Distributors - Non-English
 
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 
Stimulator pool - MRI Technician and Technologist Jobs - Intraoperative MRI - Musculoskeletal and Joint MRI - Functional MRI - Nerve Stimulator
 
Echelon™ 1.5TInfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.
 
www.hitachimed.com/contentindex.asp?ID=971 From Hitachi Medical Systems America Inc.;
Hitachi expanded its portfolio with the Echelon™ 1.5T. The MRI scanner combines a compact magnet and a scalable 8-channel RF system with high-performance gradients and slew rate to select short echo times, small field of views, high matrices and thin slices. Standard features of the Echelon MRI system include higher-order active shim, RAPID (parallel imaging for use on brain MRI, body, cardiovascular imaging, and orthopedic coils), multiple coil ports, and an advanced reconstruction engine.
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Short bore
Head, body coil, spine, breast, knee, shoulder, vascular multiple array coils.
SYNCHRONIZATION
Cardiac gating, ECG/peripheral, respiratory gating
PULSE SEQUENCES
SE, IR, FSE, FIR, GE, SG, BASG, PBSG, PCIR, DWI, Radial, Angiography: TOF, FLUTE (Fluoro-triggered bolus MRA), Time-resolved MRA
IMAGING MODES
Single, multislice, volume study
PIXEL INTENSITY
Level Range: -2,000 to +4,000
Sub millimeter
POWER REQUIREMENTS
208/220/240 V, single phase
CRYOGEN USE
Low cryogen boil-off
STRENGTH
30 mT/m
150 T/m/sec
Higher-order active shim
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• View the DATABASE results for 'Echelon™ 1.5T' (2).Open this link in a new window


• View the NEWS results for 'Echelon™ 1.5T' (3).Open this link in a new window.
 
Further Reading:
  Basics:
Echelon 1.5T
   by www.hitachimed.com    
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