Résumé
Objective To investigate prospectively the changes of quantitative parameters in dynamic contrast-enhanced MRI (DCE-MRI) in cervical cancer patients before and after neoadjuvant chemotherapy (NACT).Methods Thirty-eight patients with locally advanced cervical cancer (in stage Ⅰ B2,Ⅱ A2,Ⅱ B) underwent DCE-MRI one week before and 1 month after NACT.The patients were classified into two groups:significant reaction(sCR) group and non-sCR group.The DCE-MRI pharmacokinetics parameters (mean Ktrans,mean Kep,mean Ve and mean Vp) were measured and compared between the sCR and non-sCR groups.Receiver operating characteristic (ROC) curves were constructed to describe the diagnostic accuracy of the significant parameters and their decision thresholds.Results There were 22 and 16 patients in sCR and non-sCR groups,respectively.Before NACT,the mean Ktrans was higher (P＜0.05) but the mean Ve (P＜0.05) was lower in sCR group than those in non-sCR group,and these differences were statistically significant,respectively.After NACT,the mean Ktrans (P＜0.05) and the changed value of Ktrans (P＜0.05) were significantly lower in the sCR group compared with those in the non-sCR group.The remained parameters such as Vp and Kep had no statistically difference between the two groups.When combined the parameters values before and after treatment by using ROC curves,the area under curve (AUC) of pre-mean Ktrans and /Ktrans were 0.801 (P＜0.05),0.955 (P＜0.001).The optimal cut off value for distinguishing sCR from non-sCR were the pretreatment Ktrans (0.702 0) and/Ktrans (0.043 7),and their sensitivity and specificity were 77.3％,81.2 ％,95.5％ and 81.2％,respectively.Conclusion Quantitative parameters of DCE-MRI provided a new noninvasive way to reflect the changes of hemodynamics in cervical cancer patients with NACT.The quantitative parameters,such as pre-mean Ktrans and /Ktrans could predict the treatment efficacy more precisely.
Résumé
Objective To investigate the optimal concentration of manganese-enhanced MRI (MEMRI)in the visual pathway of experimental rats.Methods Sprague-Dawley rats were intravitreally injected with 3 μL of 10 - 100 mmol/L MnCl2 ,respectively. The contrast-to-noise ratio (CNR)of MEMRI for optic nerve(ON)and midbrain superior colliculus (SC)enhancement were measured at differ-ent concentrations of MnCl2 .Results The ON and SC were all clearly detected by MEMRI 24 h after unilateral intravitreal injected 10-100 mmol/L MnCl2 ,respectively.The CNR increased with the increasing concentration of MnCl2 from 10 to 50 mmol/L;But the CNR decreased from 50 to 100 mmol/L.The enhancement of superior colliculus were higher than optic nerve.Conclusion The optimal concentration of MnCl2 is 30 mmol/L(3 μL)through intravitreal injection for the rat visual pathway on 1.5T MEMRI.