Proton magnetic spectroscopic imaging of the child's brain: the response of tumors to treatment

Our aim was to determine and/or predict response to treatment of brain tumo rs in children using proton magnetic resonance spectroscopic imaging (MRSI) . We studied 24 patients aged 10 months to 24 years, using MRI and point-re solved spectroscopy (PRESS; TR 2000 TE 65 ms) with volume preselection and phase-encoding in two dimensions on a 1.5 T imager. Multiple logistic regre ssion was used to establish independent predictors of active tumor growth. Biologically vital cell metabolites, such as N-acetyl aspartate and choline -containing compounds (Cho), were significantly different between tumor and control tissues (P < 0.001). The eight brain tumors which responded to rad iation or chemotherapy, exhibited lower Cho (P = 0.05), higher total creati ne (tCr) (P = 0.02) and lower lactate and lipid (L) (P = 0.04) than16 tumor s which were not treated (except by surgery) or did not respond to treatmen t. The only significant independent predictor of active tumor growth was tC r (P < 0.01). We suggest that tCr is useful in assessing response of brain tumors to treatment.