Relationship between fractional anisotropy of cerebral white matter and metabolite concentrations measured using (1)H magnetic resonance spectroscopy in healthy adults.
Fractional anisotropy (FA) of water diffusion in cerebral white matter (WM), derived from diffusion tensor imaging (DTI), is a sensitive index of microscopic WM integrity. Physiological and metabolic factors that explain intersubject variability in FA values were evaluated in two cohorts of healthy adults of different age spans (N=65, range: 28-50years; and N=25, age=66.6±6.2, range: 57-80years). Single voxel magnetic resonance spectroscopy (MRS) was used to measure N-acetylaspartate (NAA), total choline-containing compounds, and total creatine, bilaterally in an associative WM tract: anterior corona radiata (ACR). FA values were calculated for the underlying, proximal and two distal WM regions. Two-stage regression analysis was used to calculate the proportion of variability in FA values explained by spectroscopy measurements, at the first stage, and subject's age, at the second stage. WM NAA concentration explained 23% and 66% of intersubject variability (p<0.001) in the FA of the underlying WM in the younger and older cohorts, respectively. WM NAA concentration also explained a significant proportion of variability in FA of the genu of corpus callosum (CC), a proximal WM tract where some of the fibers contained within the spectroscopic voxel decussate. NAA concentrations also explained a significant proportion of variability in the FA values in the splenium of CC, a distal WM tract that also carries associative fibers, in both cohorts. These results suggest that MRS measurements explained a significant proportion of variability in FA values in both proximal and distal WM tracts that carry similar fiber-types.
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
S A
SA
Wijtenburg
Aerospace Medicine Consultation Division, Dayton, OH, USA.
S A
SA
McGuire
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
L M
LM
Rowland
Department of Neuroradiology, Wilford Hall Ambulatory Surgical Center, San Antonio, TX, USA.
P M
PM
Sherman
Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
J L
JL
Lancaster
Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
D F
DF
Tate
Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
L J
LJ
Hardies
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Physics, University of Maryland Baltimore County (UMBC), MD, USA.
B
B
Patel
Department of Psychiatry, Yale University and Olin Neuropsychiatric Research Center, Hartford, CT, USA.
D C
DC
Glahn
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
L E
LE
Hong
Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
P T
PT
Fox
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Physics, University of Maryland Baltimore County (UMBC), MD, USA. Electronic address: pkochunov@mprc.umaryland.edu.
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P
Kochunov
D000328:Adult; D000368:Aged; D016880:Anisotropy; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D011522:Protons; D066127:White Matter / Q000378:metabolism* / Q000473:pathology
D011522:Protons