Potential value of dynamic MR in predicting short-term effects of(chemo-)radiation therapy on cervical cancers

Abstract

Objective To investigate the potential value of MR dynamic contrast enhanced imaging (DCE)in predicting short-term effects of(chemo-)radiation therapy on cervical cancers in vivo.Methods Thirty-two patients pathologically diagnosed as cervical cancers received MR-DCE scan before therapy.The following scans were taken at the 2nd to 3rd week after the radiation or(and)chemotherapy initiated,to calculate early size change.The fourth scan was performed within one month after the therapy to judge residues.DCE derived parameters include mean time to enhancement(MTE),positive enhancement integral (PEI),time to peak(TTP),maximum slope of increase(MSI)and maximum slope of decrease(MSD).Size and DCE parameters were compared and analyzed by Mann-Whitney test and Spearman teat Results There are 20 cases in non-residue group and 12 cases in residue group.In non-residue group,the maximal lengths in both horizontal and craniocaudal directions[(47.45±13.76)mm and(38.75±10.69)mm]were smaller than that in residue group [(61.08±13.73)mm and(53.67±16.05)mm],with statistical significance(Z=-2.455 and-2.650 respectively,P＜0.05).PEI in low-enhance areas of non-residue group(0.62±0.25)was significantly higher than that in residue group(0.39±0.14)(Z=-2.919,P＜0.05).At early time after radiation started,length changing rate and volume changing rate had medium to strong negative correlations with MSI in hish-enhance areas(r=-0.577 and-0.723 respectively,P＜0.05).Conclusions For cervical cancers,those with larger lengths and lower PEI in low-enhanced areas tend to have tumor residue when radiation therapy completed.Those low MSI in high-enhance areas tend to shrink quickly.It is suggested that volume and parameters of DCE before(chemo-)radiation therapy have the potential in predicting short-term therapeutic effect. Key words: Uterine cervical neoplasms; Magnetic resonance imaging; Treatment outcome