Comparison of the pre-treatment functional MRI metrics’ efficacy in predicting Locoregionally advanced nasopharyngeal carcinoma response to induction chemotherapy

Background Functional MRI (fMRI) parameters analysis has been proven to be a promising tool of predicting therapeutic response to induction chemotherapy (IC) in nasopharyngeal carcinoma (NPC) . The study was designed to identify and compare the value of fMRI parameters in predicting early response to IC in patients with NPC. Methods This prospective study enrolled fifty-six consecutively NPC patients treated with IC from January 2021 to May 2021. Conventional diffusion weighted imaging (DWI), diffusion kurtosis imaging (DKI), intravoxel incoherent motion (IVIM) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) protocols were performed before and after IC. Parameters maps (ADC, MD, MK, D slow , D fast , PF, K trans , V e and K ep ) of the primary tumor were calculated by the Functool post-processing software. The participants were classified as responding group (RG) and non-responding group (NRG) according to Response Evaluation Criteria in Solid Tumors 1.1. The fMRI parameters were compared before and after IC and between RG with NRG. Logistic regression analysis and ROC were performed to further identify and compare the efficacy of the parameters. Results After IC, the mean values of ADC( p < 0.001), MD( p < 0.001), D slow ( p = 0.001), PF( p = 0.030) and V e ( p = 0.003) significantly increased, while MK( p < 0.001), D fast ( p = 0.009) and K ep ( p = 0.003) values decreased dramatically, while no significant difference was detected in K trans ( p = 0.130). Compared with NRG, ADC-pre( p < 0.001), MD-pre( p < 0.001) and D slow -pre( p = 0.002) values in RG were lower, while MK-pre( p = 0.017) values were higher. The areas under the ROC curves for the ADC-pre, MD-pre, MK-pre, D slow -pre and PRE were 0.885, 0.855, 0.809, 0.742 and 0.912, with the optimal cutoff value of 1210 × 10 − 6 mm 2 /s, 1010 × 10 − 6 mm 2 /s, 832 × 10 − 6 , 835 × 10 − 6 mm 2 /s and 0.799 respectively. Conclusions The pretreatment conventional DWI (ADC), DKI (MD and MK), and IVIM (D slow ) values derived from fMRI showed a promising potential in predicting the response of the primary tumor to IC in NPC patients. Trial registration This study was approved by ethics board of the Chinese PLA General Hospital, and registered on January 30, 2021, in Chinese Clinical Trial Registry ( ChiCTR2100042863 ).