Influence of MRI-CT fusion image on gross tumor volume delineation and dose distribution for radiation of primary tumors of cervical vertebra / 中华放射肿瘤学杂志

ABSTRACT

Objective To compare the differences of gross tumor volume (GTV) and dose distribution between MRI-CT fusion imaging and CT-based imaging and investigate the dose difference in the therapeutic regime.Methods Ten patients diagnosed with primary tumors of the cervical vertebra between 2013 and 2014 were enrolled.Prior to radiotherapy,the imaging data of MRI examination (GE Discovery MR 750 3.0T) were collected,transfered into the Eclipse system and subject to fusion with CT images.GTV delineation,organ at risk (OAR) delineation and dose distribution discrepancy induced by target volume differences were analyzed and statistically compared between the MRI-CT fusion and CT-based images.GTV delineation and dose parameters among different radiologists between two approches were analyzed by analysis of variance (ANOVA) and paired t-test.Non-normally distributed variables were analyzed by Wilcoxon rank-sum test.The reliability of intraclass correlation coefficient (ICC) was assessed.Results The GTVMRI-CT volume was larger compared with the GTVCT volume.The volume overlap index was 0.84±0.17.The cordMRI-CT volume was significantly less than the cordCT volume (P=0.001).For 5 radiologists,the ICCMRI-CT was larger than ICCCT.The DmaxMRI-CT of the spinal cord was (46.00± 1.09) Gy,significantly less than (52.39±1.34) Gy for the DmaxCT(P=0.014).Conclusions It is unlikely to miss the target delineation on MRI-CT fusion imaging.MRI-CT fusion imaging can minimize the discrepancy of interobserver radiologists and cause dosimetric advantages.