The Value Of Magnetic Resonance Diffusion Kurtosis Imaging In Early Assessment Of Treatment Response To Neoadjuvant Chemoradiotherapy In Cervical Cancer

Objectives:To explore the role of diffusion kurtosis imaging?DKI?and conventional diffusion-weighted imaging?DWI?in early assessing the treatment response to neoadjuvant chemoradiotherapy in cervical cancer patients.Materials and Methods:Thirty-two patients with pathologically confirmed cervical cancer who received neoadjuvant chemotherapy coupled with radiotherapy were enrolled in this prospective study.3.0T MR examinations including DKI?b factors=0,500,1000,1500,2000 sec/mm²?and DWI?b factors=0,800 sec/mm²?were performed three times:at baseline?pre?,on the 3^th day of the 1^st cycle of chemoradiotherapy?cycle1?and on the 3^th day of the 2^nd cycle of chemoradiotherapy?cycle2?.At each examination,the mean values for apparent diffusion coefficient?ADC?,mean kurtosis?MK?,mean diffusivity?MD?and the longest diameter?d?in tumors were measured;Changes of values??X?and change ratios?r?X?were also calculated.Patients were categorized into responder group?RG?and non-responder group?NRG?on the basis of tumor's longest diameters at 3^th day of the 2ⁿdd cycle according to the response evaluation criteria in solid tumors?RECIST,version1.1?.Variance analysis of repeated measurements,receiver operating characteristic curves?ROC?,and Spearman correlation were used for statistical analysis.Result:After treatment,22?68.75%?patients were classified as responders and10?31.25%?were classified as non-responders.Mean ADC values in three different time-points were of 0.903 x10^-3mm²/s?1.036 x10^-3mm²/s and 1.178 x10^-3mm²/s,respectively?p<0.001?.Mean MD values in three different time-points were of 1.154x10^-3mm²/s,1.308 x10^-3mm²/s and 1.430 x10^-3mm²/s in sequence?p<0.01?,while their mean MK values were of 1.001,0.938 and 0.932 in sequence?p=0.01?,respectively.For pretreatment parameters,MK values in responders were significantly higher than those of non-responders?1.075±0.125 vs.0.930±0.093,p=0.005,cut-off value=0.987?,whereas,the pretreatment MD and MK values show no significant differences between responders and non-responders?P>0.05?.For post-treatment parameters,all the changes of values and change ratios of mean ADC,MD,MK in responders were statistically higher than those in non-responders?al p<0.05?.The area under the curve of r?MD_cycle1,r?MK_cycle1,r?ADC_cycle1 in early treatment were of 0.974,0.847,0.889,respectively.Meanwhile,the r?MDcycle1and r?MKcycle1 were both more sensitive than r?ADCcycle1 in predicting treatment response to chemoradiotherapy?100%vs.80%,100%vs.80%;p<0.05?.Pretreatment MK value was positively associated with the final tumor response?r=0.46,P=0.008?,and?MD_cycle2,r?MD_cycle,?ADC_cycle2 and r?ADC_cycle2 also had considerable positive correlation with the final tumor response?r>0.7,p<0.001?.Conclusion:DKI could monitor early tumor response in patients with cervical cancer undergoing chemoradiotherapy,and may help guard individual therapy for clinical strategy.