Variations in apparent diffusion coefficient values following chemotherapy in pediatric neuroblastoma

Abstract

PURPOSEIn children the assessment of solid tumors' response to che-motherapy is based primarily on size reduction, which can be unreliable and a late marker, in the presence of necrosis. We aimed to establish whether apparent diffusion coefficient (ADC) values of childhood neuroblastomas show proportion-al changes in relation to chemotherapy response.METHODSWe evaluated 15 pediatric patients with abdominopelvic neuroblastomas, who had undergone MRI before and after chemotherapy. Two radiologists retrospectively analyzed all images by drawing a round uniform region-of-interest in the solid/contrast-enhancing portion of the lesions in consensus. The ADC values from pre- and postchemotherapy images were compared. RESULTSPostchemotherapy ADC values were significantly higher than those obtained before treatment (P < 0.05, for minimum, maximum, and median ADC values). CONCLUSIONOur results support diffusion-weighted MRI as a promising noninvasive biomarker of therapeutic responses. To the best of our knowledge, this is the first report to compare diffusion- weighted imaging findings before and after chemotherapy in childhood neuroblastic tumors.