title: Molecular imaging of pediatric brain tumors: comparison of tumor metabolism using ¹⁸F-FDG-PET and MRSI.
abstract: Magnetic resonance spectroscopic imaging (MRSI) and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) are non-invasive imaging techniques routinely used to evaluate tumor malignancy in adults with brain tumors. We compared the metabolic activity of pediatric brain tumors using FDG-PET and MRSI. Children (n = 37) diagnosed with a primary brain tumor underwent FDG-PET and MRSI within two weeks of each other. Tumor metabolism was classified as inactive, active or highly active using the maximum choline:N-acetyl-asparate (Cho:NAA) on MRSI and the highest tumor uptake on FDG-PET. A voxel-wise comparison was used to evaluate the area with the greatest abnormal metabolism. Agreement between methods was assessed using the percent agreement and the kappa statistic (κ). Pediatric brain tumors were metabolically heterogeneous on FDG-PET and MRSI studies. Active tumor metabolism was observed more frequently using MRSI compared to FDG-PET, and agreement in tumor classification was weak (κ = 0.16, p = 0.12), with 42 % agreement (95 % CI = 25-61 %). Voxel-wise comparison for identifying the area of greatest metabolic activity showed overlap in the majority (62 %) of studies, though exact agreement between techniques was low (29.4 %, 95 % CI = 15.1-47.5 %). These results indicate that FDG-PET and MRSI detect similar but not always identical regions of tumor activity, and there is little agreement in the degree of tumor metabolic activity between the two techniques.
authors: Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
authors: Sean J
authors: SJ
authors: Hipp
authors: Emilie A
authors: EA
authors: Steffen-Smith
authors: Nicholas
authors: N
authors: Patronas
authors: Peter
authors: P
authors: Herscovitch
authors: Jeffrey M
authors: JM
authors: Solomon
authors: Robyn S
authors: RS
authors: Bent
authors: Seth M
authors: SM
authors: Steinberg
authors: Katherine E
authors: KE
authors: Warren
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18