Diagnostic Value of Diffusion-Weighted MRI for Tumor Characterization, Differentiation and Monitoring in Pediatric Patients with Neuroblastic Tumors

Abstract

Purpose We explored the diagnostic value of diffusion-weighted MRI (DWI) for tumor characterization, differentiation and therapy monitoring in pediatric patients with extracranial neuroblastic tumors. Materials and Methods All 29 patients (14 girls, median age: 3 years) with neuroblastoma (NB, n=19), ganglioneuroblastoma (GNB, n=4) and ganglioneuroma (GN, n=6) who had had at least one in-house DWI examination since 2005 were identified and retrospectively analyzed. Two independent blinded readers measured ADC values (unit: 10-3mm 2 /s) and signal intensity ratios (SIRs) of the primary tumor and, if applicable, of the tumor after chemotherapy, metastases and tumor relapse. Results The pre-treatment ADC was 0.90±0.23 in NB/GNB and 1.70±0.36 in GN without overlap between the two entities for both readers, 0.67±0.14 in metastases and 0.72±0.18 in tumor relapse. With chemotherapy, mean ADC increased to 1.54±0.33 in NB/GNB and to 1.23±0.27 in metastases (p<0.05). The median SIRs of various tumor lesions vs. liver, vs. muscle tissue and vs. adjacent tissue were significantly higher on DWI (range: 2.4-9.9) than on ce-T1w (range: 1.0-1.8, all p<0.05). The coefficient of variation (CV) was ≤8.0% for ADC and ≤16.4% for signal intensity data. Conclusion Based on mean ADC, DWI distinguishes between NB/GNB and GN with high certainty and provides plausible quantitative data on tumor response to therapy. Lesion conspicuity, as measured by SIR, is superior on DWI, compared to ce-T1w. DWI as a noninvasive, radiation-free and widely available imaging technique should be an integral part of MR imaging for neuroblastic tumors and should undergo prospective evaluation in multicenter studies. Key Points DWI reliably distinguishes neuroblastoma/ganglioneuroblastoma from ganglioneuroma, based on the mean ADC. DWI provides plausible quantitative data on tumor response to chemotherapy. DWI offers highly superior lesion conspicuity compared to contrast-enhanced T1w imaging. DWI should be considered a standard for imaging neuroblastic tumors. Citation Format Neubauer H, Li M, Müller VR etal. Diagnostic Value of Diffusion-Weighted MRI for Tumor Characterization, Differentiation and Monitoring in Pediatric Patients with Neuroblastic Tumors. Fortschr Röntgenstr 2017; 189: 640-650.