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

Out-
      side
 



 
 'Contrast' 
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 'Contrast' found in 43 terms [] and 326 definitions []
previous     26 - 30 (of 369)     next
Result Pages : [1 2 3 4 5 6 7 8 9]  [10 11 12 13 14 15 16 17 18 19 20 ... ]
Searchterm 'Contrast' was also found in the following services: 
spacer
News  (140)  Resources  (28)  Forum  (72)  
 
Contrast Enhanced MR VenographyInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - MRA -
 
(CEMRV) A 3D dynamic contrast enhanced magnetic resonance venogram with acquisition timing to account for the later arrival of the contrast agent in the venous system. The pulse sequence used, is an enhanced 3D fast gradient echo sequence, the same sequence that is used for MR angiography.

For Ultrasound Imaging (USI) see Venous Ultrasound at Medical-Ultrasound-Imaging.com.
 
Images, Movies, Sliders:
 CE-MRA of the Carotid Arteries Colored MIP  Open this link in a new window
    
SlidersSliders Overview

 PCA-MRA 3D Brain Venography Colored MIP  Open this link in a new window
    

 
spacer
Searchterm 'Contrast' was also found in the following services: 
spacer
Radiology  (106) Open this link in a new windowUltrasound  (149) Open this link in a new window
Magnetization Transfer Contrast
 
(MTC) This MRI method increases the contrast by removing a portion of the total signal in tissue. An off resonance radio frequency (RF) pulse saturates macromolecular protons to make them invisible (caused by their ultra-short T2* relaxation times). The MRI signal from semi-solid tissue like brain parenchyma is reduced, and the signal from a more fluid component like blood is retained.
E.g., saturation of broad spectral lines may produce decreases in intensity of lines not directly saturated, through exchange of magnetization between the corresponding states; more closely coupled states will show a greater resulting intensity change. Magnetization transfer techniques make demyelinated brain or spine lesions (as seen e.g. in multiple sclerosis) better visible on T2 weighted images as well as on gadolinium contrast enhanced T1 weighted images.
Off resonance makes use of a selection gradient during an off resonance MTC pulse. The gradient has a negative offset frequency on the arterial side of the imaging volume (caudally more off resonant and cranially less off resonant). The net effect of this type of pulse is that the arterial blood outside the imaging volume will retain more of its longitudinal magnetization, with more vascular signal when it enters the imaging volume. Off resonance MTC saturates the venous blood, leaving the arterial blood untouched.
On resonance has no effect on the free water pool but will saturate the bound water pool and is the difference in T2 between the pools. Special binomial pulses are transmitted causing the magnetization of the free protons to remain unchanged. The z-magnetization returns to its original value. The spins of the bound pool with a short T2 experience decay, resulting in a destroyed magnetization after the on resonance pulse.

See also Magnetization Transfer.
spacer

• View the DATABASE results for 'Magnetization Transfer Contrast' (5).Open this link in a new window

 
Further Reading:
  News & More:
MRI of the Human Eye Using Magnetization Transfer Contrast Enhancement
   by www.iovs.org    
MRI Resources 
Intraoperative MRI - Artifacts - Contrast Enhanced MRI - Education - Guidance - Knee MRI
 
Combination Oral Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Biphasic oral contrast agents may produce either high or low signal intensities depending on the pulse sequence used, for example low signal intensity on T1 weighted MR images and high signal intensity on T2 weighted images. The combination of different oral contrast agents can generate a macroscopic cancellation of negative and positive magnetic susceptibility, thereby eliminating susceptibility artifacts.
Possible combinations are e.g., ferric ammonium citrate and corn oil, or ferrous sulfate emulsified with baby formula. Paramagnetic agents combined with oil emulsion may be used in MRI as positive abdominal contrast agents. The combination of diamagnetic barium sulfate and superparamagnetic iron oxide (SPIO) in one suspension may be a useful negative contrast agent.

See also Gastrointestinal Paramagnetic Contrast Agents, Gastrointestinal Superparamagnetic Contrast Agents, Gastrointestinal Diamagnetic Contrast Agents, Gastrointestinal Imaging.
spacer

• View the DATABASE results for 'Combination Oral Contrast Agents' (3).Open this link in a new window

 
Further Reading:
  Basics:
Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT
2000   by www.ncbi.nlm.nih.gov    
Searchterm 'Contrast' was also found in the following services: 
spacer
News  (140)  Resources  (28)  Forum  (72)  
 
Gradient Field Echo with ContrastInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
spacer

• View the DATABASE results for 'Gradient Field Echo with Contrast' (2).Open this link in a new window

Searchterm 'Contrast' was also found in the following services: 
spacer
Radiology  (106) Open this link in a new windowUltrasound  (149) Open this link in a new window
Ionic Intravenous Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Intravenous contrast agents used in MRI are distributed in the extracellular spaces of the body before being excreted. In this sense they are similar to iodinated X-ray contrast media. However, contrast agents used for MRI are quite different from conventional radiographic contrast media in structure and function and there is no known cross sensitivity between these types of contrast agents. Common MRI contrast agents use metal ions (e.g., gadolinium or manganese) complexed with organic molecules.
Gd-DTPA, an ionic linear molecule complex (gadopentetate dimeglumine) was the first marketed MRI contrast agent. Although the osmolality of this substances can be relatively high (up to 1940 mOsm/kg H2O) compared with plasma, adverse reactions and side effects are very rare. The used doses are smaller compared with radiographic contrast media.

See also Nonionic Intravenous Contrast Agents, Dotarem®, and Magnevist®.
 
Images, Movies, Sliders:
 Breast MRI Images T1 Pre - Post Contrast  Open this link in a new window
      
 
spacer

• View the DATABASE results for 'Ionic Intravenous Contrast Agents' (5).Open this link in a new window

 
Further Reading:
  Basics:
FDA Approves First Macrocyclic and Ionic Gadolinium-Contrast Agent for MRI
Friday, 22 March 2013   by www.itnonline.com    
  News & More:
Spurious Hypocalcemia After Omniscan- or OptiMARK-Enhanced Magnetic Resonance Imaging: An Algorithm for Minimizing a False-Positive Laboratory Value
   by arpa.allenpress.com    
MRI Resources 
General - Breast MRI - MR Myelography - Movies - DICOM - Research Labs
 
previous      26 - 30 (of 369)     next
Result Pages : [1 2 3 4 5 6 7 8 9]  [10 11 12 13 14 15 16 17 18 19 20 ... ]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

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



Personalized protocols (age, gender, body habitus, etc.) lead to :
more automated planning 
improved patient comfort 
better diagnostics 
optimized image quality 
nothing 

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. [ 28 March 2024]
Terms of Use | Privacy Policy | Advertising
 [last update: 2024-02-26 03:41:00]