English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Optimizing inversion-recovery bSSFP for T1 quantification at ultra high-field

Ehses, P., Bause, J., & Scheffler, K. (2016). Optimizing inversion-recovery bSSFP for T1 quantification at ultra high-field. Magnetic Resonance Materials in Physics, Biology and Medicine, 29(Supplement 1), S197-S197.

Item is

Basic

show hide
Item Permalink: http://hdl.handle.net/21.11116/0000-0000-7C34-B Version Permalink: http://hdl.handle.net/21.11116/0000-0000-C83D-B
Genre: Meeting Abstract

Files

show Files

Locators

show
hide
Locator:
Link (Publisher version)
Description:
-

Creators

show
hide
 Creators:
Ehses, P1, Author              
Bause, J1, 2, Author              
Scheffler, K1, 2, Author              
Affiliations:
1Department High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497796              
2Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497794              

Content

show
hide
Free keywords: -
 Abstract: Purpose/Introduction: Inversion-recovery bSSFP has first been proposed for T1-quantification [1], and afterwards for simultaneous T2-quantification [2]. However, the latter is highly sensitive to B0- and B1-inhomogeneity/errors [2, 3], making its quantification currently impossible at ultra high-field. T1-quantification is much more stable against these effects, especially for low flip angles [2, 3]. Thus, we restrict this work’s focus on improving T1-quantification at UHF. Subjects and Methods: IR-bSSFP can be described by a threeparameter exponential relaxation [1, 2]: S0 (signal after inversion), SStSt (steady-state signal), and T1 * (apparent relaxation). T1 and T2 can be calculated from these parameters [2, 4]. S0 can also be obtained from a low-flipangle pre-scan [6] or replaced by a T1/T2- assumption. Experiments were performed at 9.4T on a healthy volunteer with ethics approval. Whole-brain IR-bSSFP and a 4-S0-reference scan were performed using a custom-built head-coil [6]: nominal FA = 10, TR = 3 ms, 0.8 mm resolution, 14 frames, 72 shots (each: 5 s acq. + 4 s relaxation delay), TA = 10:48 min. For comparison, a MP2RAGE protocol [7, 8] was acquired. T1-maps were calculated based on a flip angle map [9] and with an inversion efficiency of 90 (from simulation). Results: Fig. 1 shows T1 * and estimated T1 vs. true T1 depending on T1/T2 (simulation). Experimental results are shown in Fig. 2 and Table 1. The T1/T2-assumption-based T1-quantification shows higher B0-sensitivity than the other IR-bSSFP data. Discussion/Conclusion: The IR-bSSFP T1-maps are comparable to the MP2RAGE’s. However, WM-T1 for the S0-reference-based data is higher, probably due to MT-effects that are lower in the lowflipangle reference. Furthermore, GM-T1 is lower in the T1/T2-assumption-based quantification (accuracy may be improved using a lower flip angle). A general problem is, that it is difficult to capture the fast dynamics after inversion, necessary for accurate S0-extrapolation. Thus, the prescan and the assumption-based approach potentially allow for sparser sampling of the recovery curve as only T1 * and SStSt are obtained from the fit. Likewise, these approaches do not require a relaxation delay between inversion pulses.

Details

show
hide
Language(s):
 Dates: 2016-09-30
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: DOI: 10.1007/s10334-016-0569-9
BibTex Citekey: EhsesBS2016
 Degree: -

Event

show
hide
Title: 33rd Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology (ESMRMB 2016)
Place of Event: Wien, Austria
Start-/End Date: -

Legal Case

show

Project information

show

Source 1

show
hide
Title: Magnetic Resonance Materials in Physics, Biology and Medicine
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 29 (Supplement 1) Sequence Number: - Start / End Page: S197 - S197 Identifier: -