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Manually adjusted versus vendor-preset definition of metabolite boundaries impact on proton metabolite ratios

Petrou, Myria; Sundgren, Pia C LU ; Pang, Yuxi; Rohrer, Suzan; Foerster, Bradley and Chenevert, Thomas L (2007) In Academic Radiology 14(3). p.3-340
Abstract

RATIONALE AND OBJECTIVES: Metabolite peak boundary definition is an important postprocessing step in proton magnetic resonance spectroscopy (1H-MRS). We compare metabolite ratios calculated using three different postprocessing strategies: software-rendered default peak boundaries, manually adjusted peak boundaries and a curve-fitting program. The first two of these methods are commercially available.

MATERIALS AND METHODS: A total of 42 spectra acquired on a 1.5-T MR unit using two-dimensional chemical shift proton MR spectroscopy (TR/TE = 1500/144 ms) were analyzed. Choline (Cho), creatine (Cr), and N-acetylaspartate (NAA) relative concentrations were derived and the following metabolite ratios were calculated: Cho/Cr, Cho/NAA,... (More)

RATIONALE AND OBJECTIVES: Metabolite peak boundary definition is an important postprocessing step in proton magnetic resonance spectroscopy (1H-MRS). We compare metabolite ratios calculated using three different postprocessing strategies: software-rendered default peak boundaries, manually adjusted peak boundaries and a curve-fitting program. The first two of these methods are commercially available.

MATERIALS AND METHODS: A total of 42 spectra acquired on a 1.5-T MR unit using two-dimensional chemical shift proton MR spectroscopy (TR/TE = 1500/144 ms) were analyzed. Choline (Cho), creatine (Cr), and N-acetylaspartate (NAA) relative concentrations were derived and the following metabolite ratios were calculated: Cho/Cr, Cho/NAA, and NAA/Cr. Metabolite concentrations/ratios were calculated using (a) default peak boundaries rendered by commercially available, postprocessing software (Functool 2000, version 2.6.0); (b) manually adjusted peak boundaries by an experienced spectroscopist, using an option offered by the same commercially available software; and (c) an offline in-house curve-fitting program. Measurements obtained with method (c) were considered as the "gold standard." Paired t-tests comparing default and adjusted metabolite ratios, as well as default and adjusted ratios with their respective curve-fit values were used for statistical analysis.

RESULTS: Significant differences between default and manually adjusted values were found for Cho/Cr ratios <1.5 and for all Cho/NAA ratios. For Cho/Cr ratios <1.5, significant differences between default and curve-fit values were present; this was not the case when comparing manually adjusted and curve-fit values. Default and manually adjusted Cho/NAA ratios were significantly higher than corresponding curve-fit ratios. Manually adjusted values were, however, closer to the curve-fit values. No significant differences were noted between default and adjusted NAA/Cr values; default and manually adjusted ratios were significantly lower than curve-fit ratios.

CONCLUSION: There can be significant differences in metabolite ratios calculated using default and manually adjusted peak limits in proton MR spectroscopy. Furthermore, Cho/Cr and NAA/Cho adjusted metabolite ratios are closer to curve-fit values, which are considered the most accurate of the three.

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Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
keywords
Adolescent, Adult, Aspartic Acid, Brain Chemistry, Child, Chlorine, Creatine, Female, Humans, Magnetic Resonance Spectroscopy, Male, Middle Aged, Protons, Software
in
Academic Radiology
volume
14
issue
3
pages
4 pages
publisher
Elsevier
external identifiers
  • Scopus:33847361811
ISSN
1076-6332
DOI
10.1016/j.acra.2006.12.011
language
English
LU publication?
no
id
9f4dff45-4907-4533-a1eb-bdcab7813589
date added to LUP
2016-04-20 13:16:52
date last changed
2017-01-01 08:23:28
@article{9f4dff45-4907-4533-a1eb-bdcab7813589,
  abstract     = {<p>RATIONALE AND OBJECTIVES: Metabolite peak boundary definition is an important postprocessing step in proton magnetic resonance spectroscopy (1H-MRS). We compare metabolite ratios calculated using three different postprocessing strategies: software-rendered default peak boundaries, manually adjusted peak boundaries and a curve-fitting program. The first two of these methods are commercially available.</p><p>MATERIALS AND METHODS: A total of 42 spectra acquired on a 1.5-T MR unit using two-dimensional chemical shift proton MR spectroscopy (TR/TE = 1500/144 ms) were analyzed. Choline (Cho), creatine (Cr), and N-acetylaspartate (NAA) relative concentrations were derived and the following metabolite ratios were calculated: Cho/Cr, Cho/NAA, and NAA/Cr. Metabolite concentrations/ratios were calculated using (a) default peak boundaries rendered by commercially available, postprocessing software (Functool 2000, version 2.6.0); (b) manually adjusted peak boundaries by an experienced spectroscopist, using an option offered by the same commercially available software; and (c) an offline in-house curve-fitting program. Measurements obtained with method (c) were considered as the "gold standard." Paired t-tests comparing default and adjusted metabolite ratios, as well as default and adjusted ratios with their respective curve-fit values were used for statistical analysis.</p><p>RESULTS: Significant differences between default and manually adjusted values were found for Cho/Cr ratios &lt;1.5 and for all Cho/NAA ratios. For Cho/Cr ratios &lt;1.5, significant differences between default and curve-fit values were present; this was not the case when comparing manually adjusted and curve-fit values. Default and manually adjusted Cho/NAA ratios were significantly higher than corresponding curve-fit ratios. Manually adjusted values were, however, closer to the curve-fit values. No significant differences were noted between default and adjusted NAA/Cr values; default and manually adjusted ratios were significantly lower than curve-fit ratios.</p><p>CONCLUSION: There can be significant differences in metabolite ratios calculated using default and manually adjusted peak limits in proton MR spectroscopy. Furthermore, Cho/Cr and NAA/Cho adjusted metabolite ratios are closer to curve-fit values, which are considered the most accurate of the three.</p>},
  author       = {Petrou, Myria and Sundgren, Pia C and Pang, Yuxi and Rohrer, Suzan and Foerster, Bradley and Chenevert, Thomas L},
  issn         = {1076-6332},
  keyword      = {Adolescent,Adult,Aspartic Acid,Brain Chemistry,Child,Chlorine,Creatine,Female,Humans,Magnetic Resonance Spectroscopy,Male,Middle Aged,Protons,Software},
  language     = {eng},
  number       = {3},
  pages        = {3--340},
  publisher    = {Elsevier},
  series       = {Academic Radiology},
  title        = {Manually adjusted versus vendor-preset definition of metabolite boundaries impact on proton metabolite ratios},
  url          = {http://dx.doi.org/10.1016/j.acra.2006.12.011},
  volume       = {14},
  year         = {2007},
}