Magnetic Resonance - Technology Information Portal Welcome to MRI Technology••


 'PRinciples of Echo Shifting using a Train of Observations' 
  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 'PRinciples of Echo Shifting using a Train of Observations' found in 1 term [] and 1 definition []
1 - 2 (of 2)     
Result Pages : [1]
MRI Resources 
Online Books - Breast MRI - Mass Spectrometry - Pediatric and Fetal MRI - Quality Advice - Intraoperative MRI
PRinciples of Echo Shifting using a Train of ObservationsInfoSheet: - Sequences - 
Types of, 
(PRESTO) PRESTO is a 3 dimensional ultrafast gradient echo sequence that combines the whole brain coverage with T2* weighted imaging. PRESTO is useful for BOLD and perfusion imaging studies. In combination with parallel imaging techniques, PRESTO provides higher temporal resolution and more coverage compared to traditional multi slice imaging. In addition, the sensitivity to susceptibility artifacts and flow phenomena is reduced, compared with EPI techniques, enabling MRI scans throughout the brain including the skull base.
See also T2 Star.
• Share the entry 'PRinciples of Echo Shifting using a Train of Observations':  Facebook  Twitter  LinkedIn  
MRI Resources 
MRI Centers - Devices - Calculation - Cardiovascular Imaging - Universities - PACS
Perfusion ImagingForum -
related threadsInfoSheet: - Sequences - 
Types of, 
(PWI - Perfusion Weighted Imaging) Perfusion MRI techniques (e.g. PRESTO - Principles of Echo Shifting using a Train of Observations) are sensitive to microscopic levels of blood flow. Contrast enhanced relative cerebral blood volume (rCBV) is the most used perfusion imaging. Both, the ready availability and the T2* susceptibility effects of gadolinium, rather than the T1 shortening effects make gadolinium a suitable agent for use in perfusion imaging. Susceptibility here refers to the loss of MR signal, most marked on T2* (gradient echo)-weighted and T2 (spin echo)-weighted sequences, caused by the magnetic field-distorting effects of paramagnetic substances.
T2* perfusion uses dynamic sequences based on multi or single shot techniques. The T2* (T2) MRI signal drop within or across a brain region is caused by spin dephasing during the rapid passage of contrast agent through the capillary bed. The signal decrease is used to compute the relative perfusion to that region. The bolus through the tissue is only a few seconds, high temporal resolution imaging is required to obtain sequential images during the wash in and wash out of the contrast material and therefore, resolve the first pass of the tracer. Due to the high temporal resolution, processing and calculation of hemodynamic maps are available (including mean transit time (MTT), time to peak (TTP), time of arrival (T0), negative integral (N1) and index.
An important neuroradiological indication for MRI is the evaluation of incipient or acute stroke via perfusion and diffusion imaging. Diffusion imaging can demonstrate the central effect of a stroke on the brain, whereas perfusion imaging visualizes the larger 'second ring' delineating blood flow and blood volume. Qualitative and in some instances quantitative (e.g. quantitative imaging of perfusion using a single subtraction) maps of regional organ perfusion can thus be obtained.
Echo planar and potentially echo volume techniques together with appropriate computing power offer real time images of dynamic variations in water characteristics reflecting perfusion, diffusion, oxygenation (see also Oxygen Mapping) and flow.
Another type of perfusion MR imaging allows the evaluation of myocardial ischemia during pharmacologic stress. After e.g., adenosine infusion, multiple short axis views (see cardiac axes) of the heart are obtained during the administration of gadolinium contrast. Ischemic areas show up as areas of delayed and diminished enhancement. The MRI stress perfusion has been shown to be more accurate than nuclear SPECT exams. Myocardial late enhancement and stress perfusion imaging can also be performed during the same cardiac MRI examination.
Images, Movies, Sliders:
 Normal Lung Gd Perfusion MRI  Open this link in a new window

Courtesy of  Robert R. Edelman

 Left Circumflex Ischemia First-pass Contrast Enhancement  Open this link in a new window
Radiology-tip.comPerfusion Scintigraphy
Radiology-tip.comBolus Injection

• View the DATABASE results for 'Perfusion Imaging' (16).Open this link in a new window

• View the NEWS results for 'Perfusion Imaging' (3).Open this link in a new window.
Further Reading:
CHAPTER 55: Ischemia
  News & More:
Motion-compensation of Cardiac Perfusion MRI using a Statistical Texture Ensemble(.pdf)
June 2003   by    
Implementation of Dual-Source RF Excitation in 3 T MR-Scanners Allows for Nearly Identical ADC Values Compared to 1.5 T MR Scanners in the Abdomen
Wednesday, 29 February 2012   by    
Turbo-FLASH Based Arterial Spin Labeled Perfusion MRI at 7 T
Thursday, 20 June 2013   by    
Measuring Cerebral Blood Flow Using Magnetic Resonance Imaging Techniques
1999   by    
Vascular Filters of Functional MRI: Spatial Localization Using BOLD and CBV Contrast
MRI Resources 
Developers - Implant and Prosthesis - Chemistry - MR Guided Interventions - Used and Refurbished MRI Equipment - Spectroscopy
     1 - 2 (of 2)     
Result Pages : [1]
 Random Page
Share This Page

Forgot your UserID/Password ?  

In 2020 your scanner will probably work with a field strength of :

      Ups uses cookies! By browsing, you agree to our use of cookies.

Magnetic Resonance - Technology Information Portal
Member of SoftWays' Medical Imaging Group - MR-TIP • Radiology-TIP • US-TIP • 
Copyright © 2003 - 2018 SoftWays. All rights reserved. [ 16 January 2019]
Terms of Use | Privacy Policy | Advertising
 [last update: 2018-03-08 05:11:00]