MR quantitation of volume and diffusion changes in the developing brain.
OBJECTIVE
Brain volume and diffusion change during maturation. Quantitation of these changes may be helpful in understanding normal brain development. We used diffusion-weighted imaging to characterize the volumetric and diffusion changes in vivo.


METHODS
We recruited 30 pediatric volunteers (aged 1 month-17 years; 14 male, 16 female). Diffusion was measured in three orthogonal directions with a b value of 1000 s/mm2. The diffusion parameters from the entire brain were calculated and fitted to a triple gaussian model. In addition, region-of-interest measurements were made in caudate, thalamus, genu and splenium of the corpus callosum, and periventricular white matter (PVWM). The brain volume was measured by counting pixels and by using the model.


RESULTS
Water diffusion of the whole brain, caudate, thalamus, genu and splenium of the corpus callosum, and PVWM decreased during maturation, with the most significant change within the first 2 years. Robust negative correlations were found between age and the measured average diffusion constant (Dav) values in each of the measured locations (P <.005). Volumes of different cerebral compartments and the total intracranial volume (ICV) increased rapidly during the first 2 years of life and then had a slower growth process through adolescence. Age was correlated with the ICV and the volume of each brain compartment (P <.005).


CONCLUSIONS
Brain diffusion decreases and brain volume increases during maturation, with the most significant changes occurring within the first 2 years of life. The brain model used in this study provides a good estimate of the increasing brain volume.
Zhang
Lijuan
L
Department of Radiology, Weill Medical College of Cornell University, New York, NY 10021, USA.
Thomas
Kathleen M
KM
Davidson
Matthew C
MC
Casey
B J
BJ
Heier
Linda A
LA
Uluğ
Aziz M
AM
D000293:Adolescent; D001921:Brain / Q000033:anatomy & histology / Q000254:growth & development*; D002421:Caudate Nucleus / Q000033:anatomy & histology / Q000254:growth & development; D002508:Cephalometry; D002552:Cerebral Ventricles / Q000033:anatomy & histology / Q000254:growth & development; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D003337:Corpus Callosum / Q000033:anatomy & histology / Q000254:growth & development; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D016011:Normal Distribution; D012016:Reference Values; D013788:Thalamus / Q000033:anatomy & histology / Q000254:growth & development