Quantitative Evaluation Of Blood Perfusion In Spinal Metastases Before And After Radiotherapy With Dynamic Contrast-enhanced Magnetic Resonance Imaging

Objective:To evaluate of blood perfusion in spinal metastases with quantitative dynamic contrast-enhanced magnetic resonance imaging.To explore the noninvasive quantitative method of evaluating for radiotherapy effect of spinal metastases objectively with magnetic resonance imaging.Materials and Methods: From December,2014 to December,2016,Confirmed as spinal metastases and prepared radiotherapy in 16 patients,a total of 20 lesions in our hospital.All patients in the group were performed with conventional magnetic resonance scan and dynamic enhancement MR scan at 1 week before treatment and one month after treatment using a 3.0T magnetic resonance scanner.Complete response group?CR?,partial response group?PR?,stable disease group?SD?and progressive disease group?PD?were divided according to RESIST measuring the change of lesion size after radiotherapy.CR?PR?SD were classified as well-controlled group.PD was classified as poor-controlled group.The data of DCE-MRI were introduced into the Syngo workstation to analyze the time-signal intensity curve?TIC?of lesions,which was mainly divided into 3 types,type ? : ascendingdescending rapidly?enhance up to the peak rapidly at the early period,contrast agent wash out rapidly at the delay period,clearance is greater than or equal to 20%?;type ? : platform?enhance up to the peak rapidly at the early period,contrast agent wash out slowly at the delay period,clearance is less than 20%?;Type ?: Continuously rising?enhance continuously,there was no definite peak in the scan phase?.Measure the semi-quantitative parameters,including time to peak?TTP?,positive enhancement integral?PEI?,initial area under the curve?iAUC?.Match the pharmacokinetic model?PK?,calculate the quantitative parameters,including the volume transport constant(K^trans),reflux constant(K_ep),extravascular extra-cellular volume fraction?Ve?.Comparing the difference of the curve shape and the parameters changes between the different groups by a Mann-Whitney U test.The evaluation of the sensitivity of spinal metastases was performed using the receiver operating characteristic curve?ROC?analysis,and the optimal threshold was determined.Results: There were 16 cases of well-controlled group and 4 cases of poor-controlled group.Before treatment,type?curve is majority,after treatment,however,? and ? type curve is majority.The TIC types in different group before treatment are different.The number of type?and ?curves in the well-controlled group is similar,and the number of type ? curve in the poor-controlled group is relatively more.There was no significant difference in the absolute values of TTP,PEI,iAUC,K^trans,K_ep and Ve between the two groups before and after treatment.The decrease of K^trans in the well-controlled group was higher than that in the poor-controlled group,which was statistically significant.ROC curve analysis showed that the efficacy of evaluation of radiotherapy was the best when the threshold was ?K^trans?%?=-40%,and the AUC was 0.917.Conclusions: Dynamic contrast-enhanced magnetic resonance imaging can be used to quantify the blood perfusion of spinal metastases before and after radiotherapy,and ?K^trans can be used to evaluate the early radiotherapy effect of spinal metastases.It can provide objective basis for individual clinical treatment.