| ObjectiveTo investigate the changes of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)parameters in rectal cancer,then to illuminate the relationship between DCE-MRI and tumor angiogenesis of rectal cancer.Finally,to study the significance of DCE-MRI in preoperative neoadjuvant chemoradiotherapy for rectal cancer,so as to provide reference for the selection of rectal cancer treatment options,preoperative evaluation,and evaluation of neoadjuvant therapy.Materials and Methods31 patients with pathological verified rectal cancer were selected.20 cases of them were treated by surgical treatment without any other one as Group A,the other 11 cases were treated with neoadjuvant chemotherapy before surgery as Group B.Group A underwent routine pelvic MRI scans and sagittal DCE-MRI before surgery,whlie Group B underwent these imaging examination above before and after preoperative chemoradiotherapy respectively.Time-intensity curve(TIC)were created from the region of interest(ROI)in the lesions,normal rectal tissue adjacent to the lesion and musculature of pelvic wall.The parameters of TIC were measured,such as the relative enhancement ratio(RE),maximum relative enhancement ratio(MRE),maximum enhancement ratio(ME)and time to peak(TTP).HE staining was performed on surgical specimens,then CD34 monoclonal antibody were used for immunohistochemical staining to evaluate microvessel density(MVD).The parameters of TIC in the lesions,normal rectal tissue and musculature of pelvic wall were compared,then the MVD and parameters of TIC between Group A and Group B were compared,followed by comparing imaging features as well as parameters of TIC of Group B between before and after chemoradiotherapy.Results1?The values of RE in rectal cancer,normal rectal tissue and musculature of pelvic wall were(135.33 + 41.37),(92.84 + 32.10)and(27.76 + 17.37)respectively,while the values of MRE were(137.69 + 41.44),(103.82 + 42.14),and(22.81 + 28.89)respectively.The difference of RE and MRE values among them was statistically significant(p<0.05).The values of ME were(1037.16 + 326.24),(897.65 + 387.01),(160.95 + 160.34)respectively,and the values of ME in rectal cancer was significantly higher than those of the other two respectively(p<0.05).In addition,the values of TTP in rectal cancer was significantly shorter than those of normal rectal tissue and musculature(p<0.05).2?There was a positive correlation between the value of ME and MVD in 31 cases of rectal cancer(p<0.05),and the correlation coefficient was 0.717;the value of RE,MRE and TTP were not significantly correlated with MVD(p>0.05).All TIC parameters showed no significant difference between Group A and Group B before preoperative chemoradiotherapy(p>0.05).The values of ME in Group A were(1017.67±297.82),which were singificantly higher than the value(708.30±97.44)in Group B after preoperative chemoradiotherapy(p<0.05),while other parameters showed no significant difference(p>0.05).MVD counts of Group A were(16.10±8.77),significantly higher than the counts(7.20±4.60)of Group B(p<0.05).3?9 cases of Group B showed residual tumor,but the tumor was significantly reduced,while the other 2 cases showed thickening of the rectal mucosa without obvious mass after preoperative chemoradiotherapy.The values of ME in Group B were(1076.15±412.42)before chemoradiotherapy,singificantly higher than the values(708.30±97.44)in Group B after preoperative chemoradiotherapy(p<0.05).However,the values of other parameters showed no significant difference(p>0.05).Conclusion1?The TIC parameters RE,ME,MRE and TTP of DCE-MRI,which were significantly higher than those of normal rectal tissue and muscle tissue,could reflect the characteristics of rectal cancer such as high perfusion and rich blood vessels,being of certain significance in the diagnosis of rectal cancer.2?The ME value of rectal cancer was positively correlated with the pathological MVD value,and the value of ME could be used as an important parameter to evaluate the microcirculation perfusion of rectal cancer.3?The value of ME was the most sensitive parameter of TIC which can reflect the density change of tumor microvessels objectively in the process of preoperative neoadjuvant chemoradiotherapy,which can be used as a reference for evaluating the neoadjuvant chemoradiotherapy. |
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