Magnetic Resonance - Technology Information Portal Welcome to MRI Technology
Info
  Sheets

Out-
      side
 



 
 'Velocity Encoding' 
SEARCH FOR    
 
  2 3 5 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Result : Searchterm 'Velocity Encoding' found in 1 term [] and 1 definition [], (+ 2 Boolean[] results
1 - 4 (of 4)     
Result Pages : [1]
Searchterm 'Velocity Encoding' was also found in the following service: 
spacer
Forum  (1)  
 
Velocity Encoding
 
(VENC) A specialized technique used for encoding flow-velocities.
The velocity encoding value is given by:
VENC = pi / gamma DELTA M1.
Gamma is the gyromagnetic ratio, and DELTA M1 is the gradient moment and is proportional to the area of the flow encoding gradient waveform.

See also Phase Contrast Sequence, Phase Contrast Angiography, and Bipolar Gradient Pulse.
 
Images, Movies, Sliders:
 PCA-MRA 3D Brain Venography Colored MIP  Open this link in a new window
    

 
spacer
 
• Share the entry 'Velocity Encoding':  Facebook  Twitter  LinkedIn  
 
• Related Searches:
    • Cardiac MRI
    • Phase Contrast Sequence
    • Angiography
    • Phase Encoding
    • Flow
 
Further Reading:
  Basics:
Non-invasively Measuring Blood Flow Using Magnetic Resonance Imaging - NOVA™ Now Available In Europe
Wednesday, 1 October 2008   by www.medicalnewstoday.com    
Magnetic resonance flow velocity and temperature mapping of a shape memory polymer foam device
Thursday, 31 December 2009   by 7thspace.com    
MRI Resources 
Used and Refurbished MRI Equipment - NMR - Cardiovascular Imaging - Absorption and Emission - Implant and Prosthesis pool - Claustrophobia
 
Phase Contrast AngiographyMRI Resource Directory:
 - MRA -
 
(PCA) With this method images of the blood flow-velocity (or any other movement of tissue) are produced. The MRI signal contains both amplitude and phase information. The phase information can be used with subtraction of images with and without a velocity encoding gradient. The signal will be directly proportional to the velocity because of the relation between blood flow-velocity and signal intensity.
This is the strength of PCA, complete suppression of stationary tissue (no velocity - no signal), the direct velocity of flow is being imaged, while in TOF (Inflow) angiography, tissue with short T1 (fat or methaemoglobin) might be visualized.
The strength of the gradient determines the sensitivity to flow. It is set by setting the aliasing or encoding velocity (VENC). Unfortunately, phase sensitization can only be acquired along one axis at a time. Therefore, phase contrast angiographic techniques tend to be 4 times slower than TOF techniques with the same matrix.

See also Phase Contrast Sequence, Magnetic Resonance Angiography, Contrast Enhanced Magnetic Resonance Angiography, Flow Effects and Flow Quantification.
 
Images, Movies, Sliders:
 PCA-MRA 3D Brain Venography Colored MIP  Open this link in a new window
    

 
spacer

• View the DATABASE results for 'Phase Contrast Angiography' (8).Open this link in a new window

 
Further Reading:
  Basics:
Magnetic resonance angiography: current status and future directions
Wednesday, 9 March 2011   by www.jcmr-online.com    
  News & More:
MR–ANGIOGRAPHY(.pdf)
MRI Resources 
MRA - Devices - NMR - Raman Spectroscopy - Libraries - Mass Spectrometry
 
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

 
spacer

• 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 'Velocity Encoding' was also found in the following service: 
spacer
Forum  (1)  
 
Flow Encoding
 
The use of phase encoding or spin tagging techniques to obtain information on the direction and velocity of flowing material.
spacer

• View the DATABASE results for 'Flow Encoding' (3).Open this link in a new window

MRI Resources 
Knee MRI - Homepages - DICOM - Online Books - Breast MRI - Implant and Prosthesis
 
     1 - 4 (of 4)     
Result Pages : [1]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

MR-TIP    
Community   
User
Pass
Forgot your UserID/Password ?    



Next big thing in MRI will be :
AI 
remote operator 
personalized protocols 
helium-free 
molecular MRI 
portable MRI 

Look
      Ups





MR-TIP.com uses cookies! By browsing MR-TIP.com, you agree to our use of cookies.

Magnetic Resonance - Technology Information Portal
Member of SoftWays' Medical Imaging Group - MR-TIP • Radiology-TIP • Medical-Ultrasound-Imaging • 
Copyright © 2003 - 2024 SoftWays. All rights reserved. [ 29 March 2024]
Terms of Use | Privacy Policy | Advertising
 [last update: 2024-02-26 03:41:00]