Three-dimensional proton MR spectroscopic imaging of premature and term neonates

BACKGROUND AND PURPOSE: Previous studies have primarily used single-voxel t echniques to obtain MR spectra from the neonatal brain. In this study, we a pplied 3D MR spectroscopic imaging techniques to detect the spatial distrib ution of MR spectroscopic imaging-detectable compounds in premature and ter m infants. The goals were to test the feasibility of obtaining 3D MR spectr oscopic images of newborns, assess the spatial variations of metabolite lev els, and determine age-dependent differences in MR spectroscopic imaging da ta. METHODS: MR spectroscopic imaging data were acquired from nine premature (p ostconceptional age, 30-34 weeks) and eight term (postconceptional age, 38- 42 weeks) neonates, all with normal clinical and neurologic outcomes. A spe cialized point-resolved spectroscopy sequence with very selective saturatio n pulses was used to select a region encompassing the majority of the brain . Phase encoding in three dimensions was performed in a 17-minute acquisiti on time to obtain 3D spectral arrays with a 1.0 cm(3) nominal spatial resol ution. RESULTS: This study showed the feasibility of detecting the 3D distribution s of choline, creatine, and N-acetylaspartate resonances in the neonatal br ain. Significant spectral differences were detected among anatomic location s and between the premature and term groups. CONCLUSION. This initial study indicates that 3D MR spectroscopic imaging o f the neonatal brain can detect anatomic and age-dependent variations in me tabolite levels. This technique seems to be a powerful tool to assess the m etabolic differences between anatomic regions and to follow the changes in cellular metabolites with brain maturation. This study also indicates the n eed for determining topologic and age-matched normative values before metab olic abnormalities in neonates can be accurately assessed by MR spectroscop y.