| Part 1 Diagnostic value of dual-energy CT in preoperative restaging for Patients with Locally Advanced Gastric Adenocarcinoma after Neoadjuvant Chemotherapy Objective To prospectively evaluate the diagnostic value of dual-energy CT(DECT)in preoperative restaging for patients with locally advanced gastric adenocarcinoma after neoadjuvant chemotherapy(NAC).Methods This prospective study was approved by the institutional review board and informed consent was obtained from each patient.From April 2013 to March 2017,85 patients with histologically-confirmed gastric adenocarcinoma were enrolled.All patients were examined using DECT before and after NAC.Two radiologists independently assessed the CT image of the patient after NAC to obtain clinical restaging after chemotherapy(ycTNM).All patients were divided into responders(grade1)and nonresponders(grade2 and grade 3)according to the tumor regression grade(Becker-TRG).The postoperative pathological staging(ypTNM)was used as the gold standard.Results In T restaging,the radiologic accuracy and rates of overdiagnosis and underdiagnosis were 40.00%(34 of 85),36.47%(31 of 85),and 23.53%(20 of 85),respectively.When patients were stratified according to the pathologic response of the primary tumor,the radiologic accuracy and rates of overdiagnosis and underdiagnosis were 35.29%(12 of 34),44.12%(15 of 34),and 20.59%(7 of 34),respectively in the responders,and 43.14%(22 of 51),31.37%(16 of 51),and 25.49%(13 of 51),respectively in the nonresponders.In N restaging,the radiologic accuracy and rates of overdiagnosis and underdiagnosis were 41.18%(35 of 85),32.94%(28 of 85),and 25.88%(22 of 85),respectively.The radiologic accuracy and rates of overdiagnosis and underdiagnosis were 32.35%(11 of 34),44.12%(15 of 34),and 23.53%(8 of 34),respectively in the responders,and 47.06%(24 of 51),25.49%(13 of 51),and 27.45%(14 of 51),respectively in the nonresponders.Conclusions Restaging using CT after neoadjuvant chemotherapy for gastric cancer is considered to be inaccurate and unreliable,misdiagnosis mainly lies in overdiagnosis.Therefore,there is an urgent need for a standard of CT restaging for gastric cancer after neoadjuvant chemotherapy to guide clinical decision-making.Part 2 Value of iodine uptake in evaluating chemotherapy effects of advanced gastric adenocarcinomaObjective To assess the iodine value in dual energy CT(DECT)for evaluating the efficacy of neoadjuvant chemotherapy on advanced gastric adenocarcinoma and comparing the standardized iodine value and nonstandardized iodine value in lesions as well as the difference in reduction ratio of iodine value before and after neoadjuvant chemotherapy.Methods A total of 48 patients with pathologically confirmed gastric adenocarcinoma via endoscopy were enrolled and neoadjuvant chemotherapy was conducted.The DECT images before and after chemotherapy were analyzed to compare the difference between the reduction ratio of standardized iodine values(which were normalized with abdominal aorta)and non-standardized iodine values in portal phase and delayed phase.According to RECIST1.1 criteria,patients were divided into response group and non-response group.The differences in iodine value as well as reduction ratio of iodine value of lesions before and after neoadjuvant chemotherapy were compared between response and non-response groups.Results(1)There were no significant differences in the reduction ratio of standardized iodine values and non-standardized iodine values before and after neoadjuvant chemotherapy in both portal phase and delayed phase(P>0.05).(2)The iodine values after neoadjuvant chemotherapy in the response group were significantly lower than those of the non-response group in the portal phase [values are expressed as(mean±standard deviation)or median(guartile deviation)][iodine uptake in portal phase(IU-P),(1.71±0.49)mg/m L vs(2.15±0.55)mg/m L,P=0.008;normalized iodine uptake in portal phase(NIU-P),(0.30±0.09)vs(0.38±0.10),P=0.003;total iodine uptake in portal phase(TIU-P): 18.30(27.15)mg vs 81.55(81.20)mg,P<0.001;normalized total iodine uptake in portal phase(NTIU-P): 15.86(22.65)vs 47.97(64.05),P<0.001].(3)The reduction ratio of total iodine uptake before and after neoadjuvant chemotherapy in response group were significantly higher than those in non-response group in both portal and delayed phase [ΔTIU-P,-83.34%(21.05%)vs-39.82%(47.90%),P<0.001;ΔNTIU-P,-80.28%(19.61%)vs-42.33%(41.12%),P<0.001;ΔTIU-D,-80.66%(19.97%)vs-36.99%(37.71%),P<0.001;ΔNTIU-D,-79.57%(24.89%)vs-37.79%(36.48%),P<0.001].Conclusions The iodine values and the reduction ratio of the iodine values after neoadjuvant chemotherapy obtained from DECT can be helpful for evaluating the efficacy of neoadjuvant chemotherapy on advanced gastric adenocarcinoma.Part 3 Diagnostic value of CT in postoperative anastomotic leakage for patients with gastric cancerObjective To evaluate the diagnostic value of CT in postoperative anastomotic leakage for patients with gastric cancer.Methods A total of 105 patients in our hospital from November 2015 to February 2018 were enrolled in this study.The clinical and CT findings were analyzed retrospectively.(1)Count the results of anastomotic leakage;(2)All patients were divided into anastomotic leakage group and non-anastomotic leakage group according to the diagnostic criteria,the clinical and CT indicators were compared between the two groups;(3)Analyze the value of contrast agent in the diagnosis of anastomotic leakage.Results(1)Twenty-seven patients suffered from anastomotic leakage,the incidence was 25.71%(27/105).(2)The average hospital stay in anastomotic leakage group was(51.89±27.29)d,which was greater than that in non-anastomotic leakage group(21.63±20.76)d(P = 0.000).The sign of anastomotic gas-liquid aggregation was statistically significant between the two groups(P = 0.000).(3)The sensitivity,specificity and accuracy were 87.50%,92.73%,and 92.06%,respectively,for contrast agent group,and 89.47%,86.96%,and 88.05%,respectively,for no contrast agent group.Conclusions CT scan is important for patients with clinically suspected anastomotic leakage.The sign of anastomotic gas-liquid aggregation,as an important indirect sign,highly suggests the possibility of anastomotic leakage. |
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