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AJNR - American Journal of Neuroradiology

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Reproducibility of Proton MR Spectroscopic Imaging (PEPSI): Comparison of Dyslexic and Normal-Reading Children and Effects of Treatment on Brain Lactate Levels during Language Tasks

Todd L. Richards^a,c, Virginia W. Berninger^d, Elizabeth H. Aylward^a, Anne L. Richards^a, Jennifer B. Thomson^d, William E. Nagy^e, Joanne F. Carlisle^f, Stephen R. Dager^a,b,c and Robert D. Abbott^d

^a Department of Radiology, University of Washington, Seattle
^b Department of Psychiatry and Behavioral Science, University of Washington, Seattle
^c Department of Bioengineering, University of Washington, Seattle
^d Department of Education, University of Washington, Seattle
^e the School of Education at Seattle Pacific University, Seattle, WA
^f the School of Education at the University of Michigan, Ann Arbor

View larger version (69K): [in a new window]   FIG 1. Spoiled GRASS MR images (200/5) with PEPSI lactate activation overlay from a participant with dyslexia. Note the large area of lactate activation in the left frontal region that is no longer observed after treatment. A, Image before treatment. B, Image after treatment.

View larger version (42K): [in a new window]   FIG 2. Bar graph of the number of averaged activated voxels (normalized to control values), as defined by increases in lactate concentration in the left frontal brain quadrant during MR spectroscopy, in both patients with dyslexia and in control subjects. Error bars indicate the standard error of the mean. The asterisk indicates that the results of comparisons between patients and control subjects were significantly different. The data were collected by using PEPSI (TR/TE, 4000/144).

View larger version (17K): [in a new window]   FIG 3. Baseline-corrected proton spectra from a dyslexic participant in the left frontal region of the brain shows significant lactate activation during the phonologic task. The inverted lactate proton doublet can be observed at 1.3 ppm during the phonologic task (left) but not during passive listening (right). The other resonance that can be observed in the spectra is NAA.