Absolute quantitation of brain metabolites with respect to heterogeneous tissue compositions in H-1-MR spectroscopic volumes. / Gussew, Alexander; Erdtel, Marko; Hiepe, Patrick; Rzanny, Reinhard; Reichenbach, Jurgen R.
In: Magnetic Resonance Materials in Physics Biology and Medicine, Vol. 25, No. 5, 10.2012, p. 321-333.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Absolute quantitation of brain metabolites with respect to heterogeneous tissue compositions in H-1-MR spectroscopic volumes
A1 - Gussew,Alexander
A1 - Erdtel,Marko
A1 - Hiepe,Patrick
A1 - Rzanny,Reinhard
A1 - Reichenbach,Jurgen R.
AU - Gussew,Alexander
AU - Erdtel,Marko
AU - Hiepe,Patrick
AU - Rzanny,Reinhard
AU - Reichenbach,Jurgen R.
PY - 2012/10
Y1 - 2012/10
N2 - <p>Referencing metabolite intensities to the tissue water intensity is commonly applied to determine metabolite concentrations from in vivo H-1-MRS brain data. However, since the water concentration and relaxation properties differ between grey matter, white matter and cerebrospinal fluid (CSF), the volume fractions of these compartments have to be considered in MRS voxels.</p><p>The impact of partial volume correction was validated by phantom measurements in voxels containing mixtures of solutions with different NAA and water concentrations as well as by analyzing in vivo H-1-MRS brain data acquired with various voxel compositions.</p><p>Phantom measurements indicated substantial underestimation of NAA concentrations when assuming homogeneously composed voxels, especially for voxels containing solution, which simulated CSF (error: a parts per thousand currency sign92%). This bias was substantially reduced by taking into account voxel composition (error: a parts per thousand currency sign10%). In the in vivo study, tissue correction reduced the overall variation of quantified metabolites by up to 35% and revealed the expected metabolic differences between various brain tissues.</p><p>Tissue composition affects extraction of metabolite concentrations and may cause misinterpretations when comparing measurements performed with different voxel sizes. This variation can be reduced by considering the different tissue types by means of combined analysis of spectroscopic and imaging data.</p>
AB - <p>Referencing metabolite intensities to the tissue water intensity is commonly applied to determine metabolite concentrations from in vivo H-1-MRS brain data. However, since the water concentration and relaxation properties differ between grey matter, white matter and cerebrospinal fluid (CSF), the volume fractions of these compartments have to be considered in MRS voxels.</p><p>The impact of partial volume correction was validated by phantom measurements in voxels containing mixtures of solutions with different NAA and water concentrations as well as by analyzing in vivo H-1-MRS brain data acquired with various voxel compositions.</p><p>Phantom measurements indicated substantial underestimation of NAA concentrations when assuming homogeneously composed voxels, especially for voxels containing solution, which simulated CSF (error: a parts per thousand currency sign92%). This bias was substantially reduced by taking into account voxel composition (error: a parts per thousand currency sign10%). In the in vivo study, tissue correction reduced the overall variation of quantified metabolites by up to 35% and revealed the expected metabolic differences between various brain tissues.</p><p>Tissue composition affects extraction of metabolite concentrations and may cause misinterpretations when comparing measurements performed with different voxel sizes. This variation can be reduced by considering the different tissue types by means of combined analysis of spectroscopic and imaging data.</p>
U2 - 10.1007/s10334-012-0305-z
DO - 10.1007/s10334-012-0305-z
M1 - Article
JO - Magnetic Resonance Materials in Physics Biology and Medicine
JF - Magnetic Resonance Materials in Physics Biology and Medicine
SN - 0968-5243
IS - 5
VL - 25
SP - 321
EP - 333
ER -