RESUMEN
PURPOSE: The aim of this study was to investigate MRI-derived diffusion weighted imaging (DWI), 1H-MR spectroscopy (1H-MRS) and arterial spin labeling (ASL) perfusion imaging in comparison with 18F-dihydroxyphenylalanine (DOPA) PET with respect to diagnostic evaluation of pediatric diffuse midline gliomas (DMG) H3K27M-mutant and wild-type. METHODS: We retrospectively analyzed 22 pediatric patients with DMG histologically proved and molecularly classified as H3K27M-mutant (12 subjects) and wild-type (10 subjects) who underwent DWI, 1H-MRS, and ASL performed within 2 weeks of 18F-DOPA PET. DWI-derived relative minimum apparent diffusion coefficient (rADC min), 1H-MRS data [choline/N-acetylaspartate (Cho/NAA), choline/creatine (Cho/Cr), and presence of lactate] and relative ASL-derived cerebral blood flow max (rCBF max) were compared with 18F-DOPA uptake Tumor/Normal tissue (T/N) and Tumor/Striatum (T/S) ratios, and correlated with histological and molecular features of DMG. Statistics included Pearson's chi-square and Mann-Whitney U tests, Spearman's rank correlation and receiver operating characteristic (ROC) analysis. RESULTS: The highest degrees of correlation among different techniques were found between T/S, rADC min and Cho/NAA ratio (p < 0.01), and between rCBF max and rADC min (p < 0.01). Significant differences between histologically classified low- and high-grade DMG, independently of H3K27M-mutation, were found among all imaging techniques (p ≤ 0.02). Significant differences in terms of rCBF max, rADC min, Cho/NAA and 18F-DOPA uptake were also found between molecularly classified mutant and wild-type DMG (p ≤ 0.02), even though wild-type DMG included low-grade astrocytomas, not present among mutant DMG. When comparing only histologically defined high-grade mutant and wild-type DMG, only the 18F-DOPA PET data T/S demonstrated statistically significant differences independently of histology (p < 0.003). ROC analysis demonstrated that T/S ratio was the best parameter for differentiating mutant from wild-type DMG (AUC 0.94, p < 0.001). CONCLUSIONS: Advanced MRI and 18F-DOPA PET characteristics of DMG depend on histological features; however, 18F-DOPA PET-T/S was the only parameter able to discriminate H3K27M-mutant from wild-type DMG independently of histology.
Asunto(s)
Neoplasias Encefálicas/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética/normas , Glioma/diagnóstico por imagen , Espectroscopía de Resonancia Magnética/normas , Imagen de Perfusión/normas , Tomografía de Emisión de Positrones/normas , Adolescente , Neoplasias Encefálicas/genética , Niño , Preescolar , Imagen de Difusión por Resonancia Magnética/métodos , Dihidroxifenilalanina/análogos & derivados , Femenino , Glioma/genética , Histonas/genética , Humanos , Espectroscopía de Resonancia Magnética/métodos , Masculino , Mutación , Imagen de Perfusión/métodos , Tomografía de Emisión de Positrones/métodos , RadiofármacosRESUMEN
Our purpose was to evaluate the diagnostic role of 18F-3,4-dihydroxyphenylalanine (DOPA) PET/CT at the time of staging in children with neuroblastoma and to investigate its ability to assess treatment response. We also investigated the prognostic value of 18F-DOPA PET/CT at the same time points. Methods: We enrolled children with neuroblastoma at onset. Before and after induction chemotherapy, all patients underwent 18F-DOPA PET/CT and 123I-metaiodobenzylguanidine (MIBG) scanning plus SPECT/CT. 18F-DOPA PET/CT results were compared with those of 123I-MIBG whole-body scanning (WBS). For each modality, patient-based analysis and lesion-based analysis were performed and sensitivity was calculated. We applied scoring systems to 123I-MIBG scanning and 18F-DOPA PET/CT (i.e.,123I-MIBG WBS score and whole-body metabolic burden [WBMB], respectively) and evaluated the association between these parameters, the principal neuroblastoma risk factors, and outcome. Results: We enrolled 16 high-risk and 2 intermediate-risk neuroblastoma patients. On patient-based analysis, sensitivity in detecting primary tumors, soft-tissue metastases, and bone or bone-marrow metastases was 83%, 50%, and 92%, respectively, for 123I-MIBG WBS versus 94%, 92%, and 100%, respectively, for 18F-DOPA PET/CT. On lesion-based analysis, the sensitivity of 18F-DOPA PET/CT in detecting soft-tissue and bone or bone-marrow metastases was 86% and 99%, respectively-significantly higher than that of 123I-MIBG WBS, at 41% and 93%, respectively. After therapy, on patient-based analysis, the sensitivity in detecting primary tumors, soft-tissue metastases, and bone or bone-marrow metastases was 72%, 33%, and 38%, respectively, for 123I-MIBG WBS versus 83%, 75% and 54%, respectively, for 18F-DOPA PET/CT. On lesion-based analysis, the sensitivity of 18F-DOPA PET/CT in detecting soft-tissue and bone or bone-marrow metastases was 77% and 86%, respectively-significantly higher than that of 123I-MIBG WBS, at 28% and 69%, respectively. During follow-up, 8 cases of disease progression and 5 deaths occurred. On multivariate analysis, only posttherapeutic 18F-DOPA WBMB (>7.5) was associated with progression-free survival. Conclusion:18F-DOPA PET/CT is more sensitive than 123I-MIBG WBS in staging neuroblastoma patients and evaluating disease persistence after chemotherapy. In a time-to-event analysis, posttherapeutic 18F-DOPA WBMB remained the only risk factor associated with disease progression.