Proton magnetic resonance spectroscopic imaging of pediatric low-grade astrocytomas

摘要: Despite their uniform histologic appearance, pediatric lowgrade astrocytomas (LGA) often exhibit a rather unpredictable clinical course. It is presently unclear whether certain specific genetic, immunologic and/or metabolic features underlie these observed variations. In order to address this question we examined the tumor distribution of choline compounds (Cho), creatine (Cr) and N-acetyl aspartate (NAA) in seven children with midline LGA by means proton magnetic resonance spectroscopy imaging (H-MRSI). Studies were performed 1.5 T GE Signa Scanner equipped standard head coil; nominal voxel size was 7.5×7.5×15 mm. This spatial resolution allowed us select independently evaluate multiple regions interest (ROI) as well areas normal brain from same individual. Normalized values signal intensities demonstrated lower NAA Cr content tumors than surrounding brain. Intratumoral Cho signals also below all but one patient. The average Cho: ratio consistently higher However, there wide variation (up fourfold) ratios different ROIs, even within tumor. Our results clearly indicate that LGAs are metabolically heterogeneous, feature may be relevant understanding variable biologic behavior. Inasmuch unique patterns some LGAs, believe systematic HMRSI studies patients help define subsets group therapeutic requirements.