English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Inverse Z‐spectrum analysis for spillover‐, MT‐, and T1‐corrected steady‐state pulsed CEST‐MRI – application to pH‐weighted MRI of acute stroke

Zaiss, M., Xu, J., Goerke, S., Khan, I., Singer, R., Gore, J., et al. (2014). Inverse Z‐spectrum analysis for spillover‐, MT‐, and T1‐corrected steady‐state pulsed CEST‐MRI – application to pH‐weighted MRI of acute stroke. NMR in Biomedicine, 27(3), 240-252. doi:10.1002/nbm.3054.

Item is

Basic

show hide
Item Permalink: http://hdl.handle.net/21.11116/0000-0001-2AC0-7 Version Permalink: http://hdl.handle.net/21.11116/0000-0001-2AC1-6
Genre: Journal Article

Files

show Files

Locators

show
hide
Description:
-

Creators

show
hide
 Creators:
Zaiss, Moritz1, Author              
Xu, J, Author
Goerke, S, Author
Khan, IS, Author
Singer, RJ, Author
Gore, JC, Author
Gochberg, DF, Author
Bachert, P, Author
Affiliations:
1Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ, German Cancer Research Center), Heidelberg, ou_persistent22              

Content

show
hide
Free keywords: -
 Abstract: Endogenous chemical exchange saturation transfer (CEST) effects are always diluted by competing effects, such as direct water proton saturation (spillover) and semi‐solid macromolecular magnetization transfer (MT). This leads to unwanted T2 and MT signal contributions that lessen the CEST signal specificity to the underlying biochemical exchange processes. A spillover correction is of special interest for clinical static field strengths and protons resonating near the water peak. This is the case for all endogenous CEST agents, such as amide proton transfer, –OH‐CEST of glycosaminoglycans, glucose or myo‐inositol, and amine exchange of creatine or glutamate. All CEST effects also appear to be scaled by the T1 relaxation time of water, as they are mediated by the water pool. This forms the motivation for simple metrics that correct the CEST signal. Based on eigenspace theory, we propose a novel magnetization transfer ratio (MTRRex), employing the inverse Z‐spectrum, which eliminates spillover and semi‐solid MT effects. This metric can be simply related to Rex, the exchange‐dependent relaxation rate in the rotating frame, and ka, the inherent exchange rate. Furthermore, it can be scaled by the duty cycle, allowing for simple translation to clinical protocols. For verification, the amine proton exchange of creatine in solutions with different agar concentrations was studied experimentally at a clinical field strength of 3 T, where spillover effects are large. We demonstrate that spillover can be properly corrected and that quantitative evaluation of pH and creatine concentration is possible. This proves that MTRRex is a quantitative and biophysically specific CEST‐MRI metric. Applied to acute stroke induced in rat brain, the corrected CEST signal shows significantly higher contrast between the stroke area and normal tissue, as well as less B1 dependence, than conventional approaches.

Details

show
hide
Language(s):
 Dates: 2014-03
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Method: -
 Identifiers: DOI: 10.1002/nbm.3054
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: NMR in Biomedicine
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: London : Heyden & Son
Pages: - Volume / Issue: 27 (3) Sequence Number: - Start / End Page: 240 - 252 Identifier: ISSN: 0952-3480
CoNE: https://pure.mpg.de/cone/journals/resource/954925574973