MAGNETIC-RESONANCE SPECTROSCOPY (MRS) IN THE EVALUATION OF PEDIATRIC BRAIN-TUMORS .2. CLINICAL ANALYSIS

Over a 1-year period (1994-1995), 75 children with brain neoplasms wer e evaluated with a new automated magnetic resonance spectroscopy (MRS) software package called Proton Brain Exam/Single-Voxel (PROBE/SV) to determine the efficacy of this modality in children. The children rang ed in age from newborn to 17 years and were comprised of 30 girls and 45 boys. The types of brain neoplasms consisted of 45 astrocytomas, 4 medulloblastomas, 2 ependymomas, 3 craniopharyngiomas, 3 germinomas, 1 pineoblastoma, 2 teratomas, 1 choroid plexus papilloma, 4 meningiomas , 2 astroblastomas, 3 rhabdoids, and 5 metastases from primary brain n eoplasms. All children underwent magnetic resonance imaging (MRI) at t he same setting as the MRS examination. The MRS examination was perfor med with the stimulated echo acquisition mode (STEAM) pulse sequence i n all children, and occasionally the point resolved spectroscopy (PRES S) sequence also was used. Qualitative spectra were obtained in all ch ildren, and at times quantification data also were obtained. We found that our spectra over the brain neoplasms were consistent with the MRS findings of brain neoplasms in the literature. There was markedly ele vated choline with markedly decreased or absent N-acetylasparate and a t times elevated lactate and lipid peaks. In children with meningiomas , there was also an elevated alanine peak. We found MRS to be extremel y useful in 1) characterizing a brain mass as a neoplasm, 2) different iating radiation necrosis and radiation-induced meningiomas from the r ecurrent primary tumor, 3) following treatment response of the primary neoplasm, 4) differentiating residual or recurrent primary neoplasm f rom postsurgical changes, and 5) identifying inactive neoplasms or neo plasms in remission.