| Objective: To investigate the application usefulness of dual-energy iodine maps, iodine values, changing rate and volume changing rate on dual-source CT(DSCT) which will evaluate the response of gastric carcinomas(GC) to preoperative neoadjuvant chemotherapy(NACT).Methods: 18 patients with advanced gastric carcinoma undergoing neoadjuvant chemotherapy in our hospital from May 2015 to December 2015 were enrolled in this prospective study. Enhanced DSCT dual-energy examinations were performed before NACT and after finished the third cycles of chemotherapy within one week, respectively. Edge outline and class circle region of interest(ROI) obtained two iodine values including Iodine-Related Attenuation(IRA)and iodine concentration(IC) which were as a reflection of the whole GC lesion, the largest cross-sectional area lesion and the representative round lesion area. The iodine values of the whole GC lesion and the largest cross-sectional area lesion were measured in arterial phase and portal venous-phase. The iodine values of the class circle ROI, the thickness of GC lesion, the iodine values of the lymphonodus and gastric cancer serosal surface adipose tissue were measured in the portal venous-phase. In arterial phase and portal venous-phase, the volume and largest cross-sectional area of GC were all measured, then compared whether the presence of their statistical difference in two phases. All the patients were divided into chemotherapy good response group(GR) and poor response group(PR) according to RECIST 1.1 criteria, then the pre-chemotherapy parameter values and post-chemotherapy changing rate of the above parameters were compared between the two groups. ROC curves were applied to analyze the response evaluation effect of all parameters changing rate.Results:1) The volume value and largest cross-sectional area value of GC have no statistical difference in comparison of arterial phase and portal venous-phase(P>0.05). The reproducibility of data measurement is good.2) All parameters exist statistically significant difference before and after NACT(P<0.05).3) All the parameters before treatment have no significant statistical difference between chemotherapy GR and PR(P>0.05).4) The %?TV and %△S value of GR group are better than PR group, there are significant statistical difference between two groups(P=0.013, P=0.021).The %?IRAentire-V, %?ICentire-V, %?IRAmax-V, %?ICmax-V, %?IRAmin-V, %?ICmin-V, %?IRAL-V, %?I CL-V values of GR group are better than PR group, and they all have significant statistical difference between two groups(P<0.05); but there are no statistical difference for %△Tmax, %?IRAaf-V, %?ICaf-V, %?IRAentire-A, %?ICentire-A, %?IRAmax-A, %?ICmax-Avalues between two groups(P>0.05).5) The areas under the ROC curve(AUC) values are 0.900, 0.850, 0.825 and 0.852 for %△ICentire-V, %?TV, %△S and %△IRAentire-V, respectively. The AUC values of the decrease rate of iodine values in portal venous-phase for GC are bigger than the AUC values of the corresponding parameters in arterial phase. In the portal venous-phase, the AUC values of %△IC of GC lesions and and lymphonodus around the lesions are all greater than the AUC values of %△IRA.6) The toatal effective dose(ED) using contrast enhancement DSCT dual-energy scan mode of the upper abdomen is(7.57±2.12) m Sv. The total ED of the normal enhanced scanning is(8.29±0.90) m Sv, there are no significantly statistical difference between two scanning modes(P=0.132).Conclusions:1) The changing rate of volume, the largest cross-sectional area of GC lesion, the changing rate of IC and IRA value for lesions all can be used to evaluate the response of NACT. The efficiency is followed by the changing rate of IC value, volume changing rate, the changing rate of IRA and the last, changing rate of maximum cross-sectional area.2) The changing rate of IC value of the lesions is superior to lymphonodus around the lesions for the response evaluation of the chemotherapy.3) The average value of ED from dual-energy enhanced scanning mode is lower than normal enhanced scanning. |
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