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

Out-
      side
 



 
 'Inversion Recovery' 
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 'Inversion Recovery' found in 13 terms [] and 30 definitions []
previous     21 - 25 (of 43)     next
Result Pages : [1 2 3]  [4 5 6 7 8 9]
Searchterm 'Inversion Recovery' was also found in the following services: 
spacer
News  (1)  Resources  (2)  Forum  (3)  
 
Black Boundary 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
NAME
Black boundary, dark boundary, contour, chemical shift, relief
DESCRIPTION
Black contours at boundaries
Black boundary artifacts are black lines following voxels where both water and fat protons are present in the same voxel. This artifact arise along the boundary of organs or tissues perpendicular to the frequency encoding direction, and occurs preferentially in gradient echo sequences with out of phase echo times.
mri safety guidance
Image Guidance
Fat suppression techniques eliminate this artifact. For artifact reducing helps a smaller water fat shift (high bandwidth), a higher matrix or/and an in phase TE.

See also Chemical Shift Artifact.
spacer
 
Further Reading:
  Basics:
What is chemical shift artefact? Why does it occur? How many Hz at 1.5 T?
   by www.revisemri.com    
MRI Resources 
Open Directory Project - Quality Advice - Contrast Enhanced MRI - MRI Reimbursement - Jobs - Hospitals
 
Brain MRIForum -
related threadsMRI Resource Directory:
 - Brain MRI -
 
Brain imaging, magnetic resonance imaging of the head or skull, cranial magnetic resonance tomography (MRT), neurological MRI - they describe all the same radiological imaging technique for medical diagnostic.
Magnetic resonance imaging of the human brain includes the anatomic description and the detection of lesions. Special techniques like diffusion weighted imaging, functional magnetic resonance imaging (fMRI) and spectroscopy provide also information about the function and chemical metabolites of the brain. MRI provides detailed pictures of brain and nerve tissues in multiple planes without obstruction by overlying bones. Brain MRI is the procedure of choice for most brain disorders. It provides clear images of the brainstem and posterior brain, which are difficult to view on a CT scan. It is also useful for the diagnosis of demyelinating disorders (disorders such as multiple sclerosis (MS) that cause destruction of the myelin sheath of the nerve).
With this noninvasive procedure also the evaluation of blood flow and the flow of cerebrospinal fluid (CSF) is possible. Different MRA methods, also without contrast agents can show a venous or arterial angiogram. MRI can distinguish tumors, inflammatory lesions, and other pathologies from the normal brain anatomy. However, MRI scans are also used instead other methods to avoid the dangers of interventional procedures like angiography (DSA - digital subtraction angiography) as well as of repeated exposure to radiation as required for computed tomography (CT) and other X-ray examinations.
A (birdcage) bird cage coil achieves uniform excitation and reception and is commonly used to study the brain. Usually a brain MRI procedure includes FLAIR, T2 weighted and T1 weighted sequences in two or three planes.

See also Fetal MRI, Fluid Attenuation Inversion Recovery (FLAIR), Perfusion Imaging and High Field MRI.
See also Arterial Spin Labeling.
 
Images, Movies, Sliders:
 Brain MRI Images Axial T2  Open this link in a new window
      

 MRI of the Skull Base  Open this link in a new window
    
SlidersSliders Overview

 Anatomic Imaging of the Orbita  Open this link in a new window
      

 Brain MRI Images T1  Open this link in a new window
 MRI of the Brain Stem with Temoral Bone and Auditory System  Open this link in a new window
    
SlidersSliders Overview

 TOF-MRA Circle of Willis Inverted MIP  Open this link in a new window
    

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

 
Medical-Ultrasound-Imaging.comA-Mode
spacer

• View the DATABASE results for 'Brain MRI' (14).Open this link in a new window


• View the NEWS results for 'Brain MRI' (32).Open this link in a new window.
 
Further Reading:
  Basics:
New MRI technique offers faster diagnosis of multiple sclerosis
Monday, 1 February 2016   by medicalxpress.com    
Ultra-high-field MRI reveals language centres in the brain in much more detail
Tuesday, 28 October 2014   by medicalxpress.com    
A Dutch study has revealed that as many as 13% of healthy adults may have some type of undiagnosed abnormality in the brain.
Sunday, 4 November 2007   by www.news-medical.net:80    
  News & More:
MRI Reveals Significant Brain Abnormalities Post-COVID
Monday, 21 November 2022   by neurosciencenews.com    
Combining genetics and brain MRI can aid in predicting chances of Alzheimer's disease
Wednesday, 29 June 2022   by www.sciencedaily.com    
Roundup: How Even Mild COVID Can Affect the Brain; This Many Daily Steps Improves Longevity; and More
Friday, 11 March 2022   by baptisthealth.net    
A low-cost and shielding-free ultra-low-field brain MRI scanner
Tuesday, 14 December 2021   by www.nature.com    
Large International Study Reveals Spectrum of COVID-19 Brain Complications
Tuesday, 9 November 2021   by www.itnonline.com    
Brain MRI-Based Subtypes of MS Predict Disability Progression, Treatment Response
Thursday, 13 May 2021   by www.neurologyadvisor.com    
New MRI method improves detection of disease changes in the brain's network
Thursday, 11 June 2020   by www.compute.dtu.dk    
New NeuroCOVID Classification System Uses MRI to Categorize Patients
Friday, 12 June 2020   by www.diagnosticimaging.com    
New MRI technique can 'see' molecular changes in the brain
Thursday, 5 September 2019   by medicalxpress.com    
Talking therapy or medication for depression: Brain scan may help suggest better treatment
Monday, 27 March 2017   by www.newsnation.in    
MRI identifies brain abnormalities in chronic fatigue syndrome patients
Wednesday, 29 October 2014   by www.eurekalert.org    
MRIs Useful in Tracking Depression in MS Patients
Tuesday, 1 July 2014   by www.hcplive.com    
Contrast agent linked with brain abnormalities on MRI
Tuesday, 17 December 2013   by www.sciencecodex.com    
MRIs Reveal Signs of Brain Injuries Not Seen in CT Scans
Tuesday, 18 December 2012   by www.sciencedaily.com    
Iron Deposits in the Brain May Be Early Indicator of MS
Wednesday, 13 November 2013   by www.healthline.com    
Migraine Sufferers Have Thicker Brain Cortex
Tuesday, 20 November 2007   by www.medicalnewstoday.com    
MRI Resources 
Diffusion Weighted Imaging - Education pool - Pacemaker - Process Analysis - MRI Centers - Libraries
 
Chemical Shift 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
NAME
Chemical shift, black boundary, spatial misregistration, relief
DESCRIPTION
Black or bright band
During frequency encoding, fat protons precess slower than water protons in the same slice because of their magnetic shielding. Through the difference in resonance frequency between water and fat, protons at the same location are misregistrated (dislocated) by the Fourier transformation, when converting MRI signals from frequency to spatial domain. This chemical shift misregistration cause accentuation of any fat-water interfaces along the frequency axis and may be mistaken for pathology. Where fat and water are in the same location, this artifact can be seen as a bright or dark band at the edge of the anatomy.
Protons in fat and water molecules are separated by a chemical shift of about 3.5 ppm. The actual shift in Hertz (Hz) depends on the magnetic field strength of the magnet being used. Higher field strength increases the misregistration, while in contrast a higher gradient strength has a positive effect. For a 0.3 T system operating at 12.8 MHz the shift will be 44.8 Hz compared with a 223.6 Hz shift for a 1.5 T system operating at 63.9 MHz.
mri safety guidance
Image Guidance
For artifact reduction helps a smaller water fat shift (higher bandwidth), a higher matrix, an in phase TE or a spin echo technique. Since the misregistration offset is present in the read out axis the patient may be rescanned with this axis parallel to the fat-water interface. Steeper gradient may be employed to reduce the chemical shift offset in mm. Another strategy is to employ specialized pulse sequences such as fat saturation or inversion recovery imaging. Fat suppression techniques eliminate chemical shift artifacts caused by the lack of fat signal.

See also Black Boundary Artifact and Magnetic Resonance Spectroscopy.
spacer

• View the DATABASE results for 'Chemical Shift Artifact' (7).Open this link in a new window

 
Further Reading:
  Basics:
MRI Artifact Gallery
   by chickscope.beckman.uiuc.edu    
  News & More:
What is chemical shift artefact? Why does it occur? How many Hz at 1.5 T?
   by www.revisemri.com    
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by www.ajronline.org    
Searchterm 'Inversion Recovery' was also found in the following services: 
spacer
News  (1)  Resources  (2)  Forum  (3)  
 
Chemical Shift ImagingInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Spectroscopy pool -
 
(CSI) Chemical shift imaging is an extension of MR spectroscopy, allowing metabolite information to be measured in an extended region and to add the chemical analysis of body tissues to the potential clinical utility of Magnetic Resonance. The spatial location is phase encoded and a spectrum is recorded at each phase encoding step to allow the spectra acquisition in a number of volumes covering the whole sample. CSI provides mapping of chemical shifts, analog to individual spectral lines or groups of lines.
Spatial resolution can be in one, two or three dimensions, but with long acquisition times od full 3D CSI. Commonly a slice-selected 2D acquisition is used. The chemical composition of each voxel is represented by spectra, or as an image in which the signal intensity depends on the concentration of an individual metabolite. Alternatively frequency-selective pulses excite only a single spectral component.
There are several methods of performing chemical shift imaging, e.g. the inversion recovery method, chemical shift selective imaging sequence, chemical shift insensitive slice selective RF pulse, the saturation method, spatial and chemical shift encoded excitation and quantitative chemical shift imaging.

See also Magnetic Resonance Spectroscopy.
spacer

• View the DATABASE results for 'Chemical Shift Imaging' (6).Open this link in a new window

 
Further Reading:
  Basics:
1H MR Spectroscopy and Chemical Shift Imaging of the In Vivo Brain at 7 Tesla
Sunday, 26 November 2006   by tobias-lib.uni-tuebingen.de    
MRI evaluation of fatty liver in day to day practice: Quantitative and qualitative methods
Wednesday, 3 September 2014   by www.sciencedirect.com    
  News & More:
Spin echoes, CPMG and T2 relaxation - Introductory NMR & MRI from Magritek
2013   by www.azom.com    
mDIXON being developed to simplify and accelerate liver MRI
September 2010   by incenter.medical.philips.com    
MRI Resources 
Safety Training - Online Books - Universities - Musculoskeletal and Joint MRI - Manufacturers - Absorption and Emission
 
ContrastForum -
related threads
 
Contrast is the relative difference of signal intensities in two adjacent regions of an image.
Due to the T1 and T2 relaxation properties in magnetic resonance imaging, differentiation between various tissues in the body is possible. Tissue contrast is affected by not only the T1 and T2 values of specific tissues, but also the differences in the magnetic field strength, temperature changes, and many other factors. Good tissue contrast relies on optimal selection of appropriate pulse sequences (spin echo, inversion recovery, gradient echo, turbo sequences and slice profile).
Important pulse sequence parameters are TR (repetition time), TE (time to echo or echo time), TI (time for inversion or inversion time) and flip angle. They are associated with such parameters as proton density and T1 or T2 relaxation times. The values of these parameters are influenced differently by different tissues and by healthy and diseased sections of the same tissue.
For the T1 weighting it is important to select a correct TR or TI. T2 weighted images depend on a correct choice of the TE. Tissues vary in their T1 and T2 times, which are manipulated in MRI by selection of TR, TI, and TE, respectively. Flip angles mainly affect the strength of the signal measured, but also affect the TR/TI/TE parameters.
Conditions necessary to produce different weighted images:
T1 Weighted Image: TR value equal or less than the tissue specific T1 time - TE value less than the tissue specific T2 time.
T2 Weighted Image: TR value much greater than the tissue specific T1 time - TE value greater or equal than the tissue specific T2 time.
Proton Density Weighted Image: TR value much greater than the tissue specific T1 time - TE value less than the tissue specific T2 time.

See also Image Contrast Characteristics, Contrast Reversal, Contrast Resolution, and Contrast to Noise Ratio.
 
Images, Movies, Sliders:
 Fetus (Brain) and Dermoid in Mother  Open this link in a new window
      

Courtesy of  Robert R. Edelman

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

 Anatomic MRI of the Knee 1  Open this link in a new window
    
SlidersSliders Overview

 Anatomic Imaging of the Liver  Open this link in a new window
      

 Brain MRI Inversion Recovery  Open this link in a new window
    
 
spacer

• View the DATABASE results for 'Contrast' (373).Open this link in a new window


• View the NEWS results for 'Contrast' (77).Open this link in a new window.
 
Further Reading:
  Basics:
Magnetic resonance imaging
   by www.scholarpedia.org    
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
Image Characteristics and Quality
   by www.sprawls.org    
  News & More:
A natural boost for MRI scans
Monday, 21 October 2013   by www.eurekalert.org    
A groundbreaking new graphene-based MRI contrast agent
Friday, 8 June 2012   by www.nanowerk.com    
New MRI Chemical Offers Amazing Contrast
Friday, 22 January 2010   by news.softpedia.com    
MRI Resources 
Manufacturers - Pregnancy - Shielding - Distributors - Spine MRI - Brain MRI
 
previous      21 - 25 (of 43)     next
Result Pages : [1 2 3]  [4 5 6 7 8 9]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

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



New acceleration techniques will :
reduce scan times 
cause artifacts 
increase expenses 
be useful if you have a lot of experience 
doesn't do much 
never heard of 

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]