IntroductionDiffusion-weighted MR imaging (DWI) has demonstrated a great potential to help distinguish benign from malignant tumours in paediatric body. Our purpose is to evaluate whether DWI allow discrimination of thoracoabdominal neuroblastic tumours of various histological types and differentiation grades. MethodsWe retrospectively analysed DWI scans of the thoracoabdominal neuroblastic tumours in 25 children (11 girls, 14 boys). DWI was performed with two b-values of 0 and 800s/mm(2) on a 3.0T MR scanner. The apparent diffusion coefficient (ADC) values of different classifications of tumours were compared with Independent-Samples T Test. ResultsIn the 25 cases, ganglioneuroma (GN) was in 3 cases, ganglioneuroblastoma (GNB) in 7 (GNB-Intermixed in 4, GNB-Nodular in 3) and neuroblastoma (NB) in 15. In three cases of GNB-Nodular, two cases had poorly differentiated nodules and another had differentiated nodules. In 15 cases of NB, poorly differentiated, differentiated and undifferentiated tumours were, respectively, in eight, five and two cases. The ADC value of the NB was significantly lower than that of GN/GNB (P<0.001). The ADC of GNB-Nodular/NB was significantly less than that of GN/GNB-Intermixed (P<0.0001). In GNB-Nodular/NB detection, there was a cut-off value of 1.165x10(-3)mm(2)/s. In GNB-Nodular/NB, the tumours with poorly differentiated and undifferentiated lesions (n=12) had significantly smaller ADC than those with differentiated composition (n=6) (P=0.0012). ConclusionADC of DWI is highly valuable for discriminating thoracoabdominal neuroblastic tumours of different histological types and differentiation grades.