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Result : Searchterm 'cardiac' found in 11 terms [] and 75 definitions []
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Searchterm 'cardiac' was also found in the following services: 
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Displacement Encoding with Stimulated EchoesInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(DENSE) Displacement Encoding with Stimulated Echoes is a functional cardiac MRI pulse sequence, used to create maps of myocardial displacement with high resolution.
The DENSE magnitude images produce black blood images to show better myocard-blood contrast and to reduce motion artifacts.

See also Myocardial Late Enhancement, Spin Tagging, Coronary Angiography with D-Tagging, Cardiovascular Imaging, and Black Blood MRA.
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Further Reading:
  Basics:
Latest Pulse Sequence for Displacement-encoded MR Imaging Incorporates Essential Technical Improvements for Multiphase Measurement of Intramyocardial Strain
March 2004   by radiology.rsna.org    
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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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FlowForum -
related threads
 
Flow phenomena are intrinsic processes in the human body. Organs like the heart, the brain or the kidneys need large amounts of blood and the blood flow varies depending on their degree of activity. Magnetic resonance imaging has a high sensitivity to flow and offers accurate, reproducible, and noninvasive methods for the quantification of flow. MRI flow measurements yield information of blood supply of of various vessels and tissues as well as cerebro spinal fluid movement.
Flow can be measured and visualized with different pulse sequences (e.g. phase contrast sequence, cine sequence, time of flight angiography) or contrast enhanced MRI methods (e.g. perfusion imaging, arterial spin labeling).
The blood volume per time (flow) is measured in: cm3/s or ml/min. The blood flow-velocity decreases gradually dependent on the vessel diameter, from approximately 50 cm per second in arteries with a diameter of around 6 mm like the carotids, to 0.3 cm per second in the small arterioles.

Different flow types in human body:
Behaves like stationary tissue, the signal intensity depends on T1, T2 and PD = Stagnant flow
Flow with consistent velocities across a vessel = Laminar flow
Laminar flow passes through a stricture or stenosis (in the center fast flow, near the walls the flow spirals) = Vortex flow
Flow at different velocities that fluctuates = Turbulent flow

See also Flow Effects, Flow Artifact, Flow Quantification, Flow Related Enhancement, Flow Encoding, Flow Void, Cerebro Spinal Fluid Pulsation Artifact, Cardiovascular Imaging and Cardiac MRI.
 
Images, Movies, Sliders:
 MVP Parasternal  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 TOF-MRA Circle of Willis Inverted MIP  Open this link in a new window
    

 Circle of Willis, Time of Flight, MIP  Open this link in a new window
    
SlidersSliders Overview

 
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• View the DATABASE results for 'Flow' (113).Open this link in a new window


• View the NEWS results for 'Flow' (7).Open this link in a new window.
 
Further Reading:
  News & More:
The super-fast MRI scan that could revolutionise heart failure diagnosis
Wednesday, 21 September 2022   by www.eurekalert.org    
Searchterm 'cardiac' was also found in the following services: 
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Flow 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
DESCRIPTION
Vascular ghosts (ghosting artifact), anomalous intensities in images
REASON
Movement of body fluids
HELP
Flow compensation, presaturation, triggering
Flow effects in MRI produce a range of artifacts, e.g. intravascular signal void by time of flight effects; turbulent dephasing and first echo dephasing, caused by flowing blood.
Through movement of the hydrogen nuclei (e.g. blood flow), there is a location change between the time these nuclei experience a radio frequency pulse and the time the emitted signal is received (because the repetition time is asynchronous with the pulsatile flow).
The blood flow occasionally produces intravascular high signal intensities due to flow related enhancement, even echo rephasing and diastolic pseudogating. The pulsatile laminar flow within vessels often produces a complex multilayered band that usually propagates outside the head in the phase encoded direction. Blood flow artifacts should be considered as a special subgroup of motion artifacts.
mri safety guidance
Image Guidance
Artifacts can be reduced by reduction of phase shifts with flow compensation (gradient moment nulling), suppression of the blood signal with saturation pulses parallel to the slices, synchronization of the imaging sequence with the heart cycle (cardiac triggering) or can be flipped 90° by swapping the phase//frequency encoding directions.

See also Flow Related Enhancement and Flow Effects.
 
Images, Movies, Sliders:
 Knee MRI Sagittal T1 003  Open this link in a new window
 
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• View the DATABASE results for 'Flow Artifact' (6).Open this link in a new window

 
Further Reading:
  News & More:
MRI measure of blood flow over atherosclerotic plaque may detect dangerous plaque
Friday, 5 April 2013   by www.sciencecodex.com    
Advanced Visualization Techniques Could Change the Paradigm for Diagnosis and Treatment of Heart Disease
Thursday, 31 May 2012   by www.sciencedaily.com    
MRI Resources 
IR - Libraries - Blood Flow Imaging - Used and Refurbished MRI Equipment - MRCP - Sequences
 
Flow QuantificationInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
Quantification relies on inflow effects or on spin phase effects and therefore on quantifying the phase shifts of moving tissues relative to stationary tissues.
With properly designed pulse sequences (see phase contrast sequence) the pixel by pixel phase represents a map of the velocities measured in the imaging plane. Spin phase effect-based flow quantification schemes use pulse sequences specifically designed so that the phase angle in a pixel obtained upon measuring the signal is proportional to the velocity. As the relation of the phase angle to the velocity is defined by the gradient amplitudes and the gradient switch-on times, which are known, velocity can be determined quantitatively on a pixel-by-pixel basis. Once, this velocity is known, the flow in a vessel can be determined by multiplying the pixel area with the pixel velocity. Summing this quantity for all pixels inside a vessel results in a flow volume, which is measured, e.g. in ml/sec.
Flow related enhancement-based flow quantification techniques (entry phenomena) work because spins in a section perpendicular to the vessel of interest are labeled with some radio frequency RF pulse. Positional readout of the tagged spins some time T later will show the distance D they have traveled.
For constant flow, the velocity v is obtained by dividing the distance D by the time T : v = D/T. Variations of this basic principle have been proposed to measure flow, but the standard methods to measure velocity and flow use the spin phase effect.
Cardiac MRI sequences are used to encode images with velocity information. These pulse sequences permit quantification of flow-related physiologic data, such as blood flow in the aorta or pulmonary arteries and the peak velocity across stenotic valves.
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• View the DATABASE results for 'Flow Quantification' (6).Open this link in a new window

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