Assessment of functional development in normal infant brain using arterial spin labeled perfusion MRI

Abstract

Arterial spin labeled (ASL) perfusion MRI provides a noninvasive approach for longitudinal imaging of regional brain function in infants. In the present study, continuous ASL (CASL) perfusion MRI was carried out in normally developing 7- and 13-month-old infants while asleep without sedation. The 13-month infant group showed an increase (P<0.05) of relative CBF in frontal regions as compared to the 7-month group using a region of interest based analysis. Using a machine-learning algorithm to automatically classify the relative CBF maps of the two infant groups, a significant (P<0.05, permutation testing) regional CBF increase was found in the hippocampi, anterior cingulate, amygdalae, occipital lobes, and auditory cortex in the 13-month-old infants. These results are consistent with current understanding of infant brain development and demonstrate the feasibility of using perfusion MRI to noninvasively monitor developing brain function.

Figure 1

Relative CBF maps (normalized to 50 ml/100g/min) from 7 month old (n=8, TOP) and 13 month old (n=8, MIDDLE) infants, along with a difference image showing increased CBF in frontal regions with development (BOTTOM).

Figure 2

ROI analysis showing changes in relative CBF within sensorimotor, visual, auditory, and frontal regions.

Figure 3

The spatial relative CBF discrepancy map between the 13-month group and 7-month group. Red means greater in the 13-month group; blue means greater in the 7-month group. A) whole brain perfusion discrepancy map without thresholding, B) suprathresholded perfusion difference map with cluster size greater than 80; the threshold for permutation probability is P<0.05.