Infiltrative astrocytomas (IAs) represent a group of astrocytic gliomas ranging from low-grade to highly malignant, characterized by diffuse invasion of the brain parenchyma. When compared with their adult counterpart, pediatric IAs may be considered biologically distinct entities; nevertheless, similarly to those in adults they represent a complex oncologic challenge. The aim of this study was to investigate the diagnostic role, clinical contribution, and prognostic value of fused 18F-3,4-dihydroxyphenylalanine ( 18FDOPA) PET/MR images in pediatric supratentorial IAs. Methods: Pediatric patients with supratentorial IAs involving at least 2 cerebral lobes, either newly diagnosed or with suspected disease progression, prospectively underwent 18F-DOPA PET and conventional MR imaging, performed within 10 d of each other. 18F-DOPA PET data were interpreted qualitatively and semiquantitatively, fusing images with MR images. PET scans were classified as positive if tumors identified on MR imaging exhibited tracer uptake above the level of the corresponding contralateral normal brain. Maximum standardized uptake values, tumor-to-normal contralateral tissue ratios, and tumor-to-normal striatum ratios were calculated for all tumors. Correlations between the degree and extent of 18F-DOPA uptake, MR imaging tumor characteristics, and histologic results were investigated. The contribution of 18F-DOPA PET/MR image fusion was considered relevant if it enabled one to select the most appropriate biopsy site, discriminate between disease progression and treatmentrelated changes, or influence treatment strategy. The patient's outcome was finally correlated with 18F-DOPA uptake. Results: Thirteen patients (8 boys and 5 girls) were included (5 diffuse astrocytomas, 2 anaplastic astrocytomas, 5 gliomatosis cerebri, and 1 glioblastoma multiforme). The 18F-DOPA uptake pattern was heterogeneous in all positive scans (9/13), revealing metabolic heterogeneities within each tumor. Significant differences in terms of 18F-DOPA uptake were found between low- and high-grade lesions (P<0.05). The diagnostic and therapeutic contribution of 18F-DOPA PET/MR image fusion was relevant in 9 of 13 patients (69%). 18F-DOPA uptake correlated significantly with progression-free survival (P=0.004). Conclusion: Our results indicate that 18F- DOPAPET/MRimage fusionmaybea reliable imaging biomarker of pediatric IAs. Information gathered by this combined imaging approach can be readily transferred to the everyday practice and may help clinicians to better stratify patients with IAs, especially diffuse astrocytomas and gliomatosis © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
Value of 18F-3,4-dihydroxyphenylalanine pet/mr image fusion in pediatric supratentorial infiltrative astrocytomas: A prospective pilot study
Morana G.;Puntoni M.;Nozza P.;Cama A.;Zefiro D.;Rossi A.;Garre M. L.
2014-01-01
Abstract
Infiltrative astrocytomas (IAs) represent a group of astrocytic gliomas ranging from low-grade to highly malignant, characterized by diffuse invasion of the brain parenchyma. When compared with their adult counterpart, pediatric IAs may be considered biologically distinct entities; nevertheless, similarly to those in adults they represent a complex oncologic challenge. The aim of this study was to investigate the diagnostic role, clinical contribution, and prognostic value of fused 18F-3,4-dihydroxyphenylalanine ( 18FDOPA) PET/MR images in pediatric supratentorial IAs. Methods: Pediatric patients with supratentorial IAs involving at least 2 cerebral lobes, either newly diagnosed or with suspected disease progression, prospectively underwent 18F-DOPA PET and conventional MR imaging, performed within 10 d of each other. 18F-DOPA PET data were interpreted qualitatively and semiquantitatively, fusing images with MR images. PET scans were classified as positive if tumors identified on MR imaging exhibited tracer uptake above the level of the corresponding contralateral normal brain. Maximum standardized uptake values, tumor-to-normal contralateral tissue ratios, and tumor-to-normal striatum ratios were calculated for all tumors. Correlations between the degree and extent of 18F-DOPA uptake, MR imaging tumor characteristics, and histologic results were investigated. The contribution of 18F-DOPA PET/MR image fusion was considered relevant if it enabled one to select the most appropriate biopsy site, discriminate between disease progression and treatmentrelated changes, or influence treatment strategy. The patient's outcome was finally correlated with 18F-DOPA uptake. Results: Thirteen patients (8 boys and 5 girls) were included (5 diffuse astrocytomas, 2 anaplastic astrocytomas, 5 gliomatosis cerebri, and 1 glioblastoma multiforme). The 18F-DOPA uptake pattern was heterogeneous in all positive scans (9/13), revealing metabolic heterogeneities within each tumor. Significant differences in terms of 18F-DOPA uptake were found between low- and high-grade lesions (P<0.05). The diagnostic and therapeutic contribution of 18F-DOPA PET/MR image fusion was relevant in 9 of 13 patients (69%). 18F-DOPA uptake correlated significantly with progression-free survival (P=0.004). Conclusion: Our results indicate that 18F- DOPAPET/MRimage fusionmaybea reliable imaging biomarker of pediatric IAs. Information gathered by this combined imaging approach can be readily transferred to the everyday practice and may help clinicians to better stratify patients with IAs, especially diffuse astrocytomas and gliomatosis © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
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