RESUMO
Objective:To explore the application value of compute tomography(CT)scan with 16cm wide body detector in chest examination of patients who could not cooperate with breath-holding.Methods:A total of 100 patients who could not cooperate with breath-holding during chest examination in the second affiliated hospital of Shenyang Medical College from May to August in 2022 were selected,and they were randomly divided into observation group and control group,with 50 patients in each group.The collimation width of CT scan with 16cm wide body detector was 256 mm×0.625 mm in the observation group,and that with 8 cm wide body detector was 128 mm×0.625 mm in the control group,and other parameters of two groups were same.A series of indicators included age,height,weight and body mass index(BMI)of patients were recorded,and the CT dose index(CTDIvol),dose length product(DLP),effective dose(ED)were measured and calculated.And then,the Contrast to Noise ratio(CNR),signal to noise(SNR)and Standard Deviation(SD)between two groups were compared,and the image quality was evaluated objectively and subjectively.Results:The average age and the average weight of the patients in the observation group were respectively(78.81±6.84)years old and(64.46±9.86)kg,and the mean values of BMI,CTDIvol,DLP,ED and exposure time were respectively(22.89±3.09)kg/m2,(4.61±1.00)mGy,(1 471.02±345.25)mGy·cm,(20.59±4.83)mSv,(1.01±0.61)s.The average age and the average weight of the patients in the control group were respectively(77.70±6.76)years old and(62.84±4.75)kg.The mean values of BMI,CTDIvol,DLP,Ed and exposure time were respectively(22.89±2.29)kg/m2,(14.5±0.00)mGy,(4 561.70±346.32)mGy·cm,(63.86±4.85)mSv and(4.07±0.12)s.The differences of subjective evaluations of main pulmonary artery,right inferior pulmonary vein trunk and aortic arch between the observation group and the control group were not significant(P>0.05).The subjective scores of image qualities both two groups were larger than 4,and the image qualities of two groups could meet the diagnostic requirements.The CTDIvol,DLP,ED and exposure time of observation group were significantly lower than those in control group(t=-69.42,-44.231,-44.234,-107.10,P<0.05),respectively.Conclusion:Compared with the CT scan with conventional 8 cm detector,the CT scan with 16 cm wide body detector can greatly shorten the scanning time and reduce the radiation dose in the chest CT scan of patients with free breathing,and the image quality of that can meet the requirement of clinical diagnosis,which has very high application value in the fast diagnosis of clinical emergency.