ABSTRACT
Objective To explore the feasibility of reducing radiation dose and iodine contrast medium in 70 kVp abdominal CTA imaging in low-body mass index (BMI;≤22 kg/m2) patients.Methods The 48 patients with suspected abdominal vascular diseases and low BMI (≤22 kg/m2) underwent abdominal CTA.All patients were divided into two groups according to tube voltage and contrast intake randomly.The parameters of group A (n=27) were contrast intake 300 mgI/kg,70 kVp,the conditions of group B (n=21) were contrast intake 500 mgI/kg,120 kVp,and the other conditions were the same in both groups.The image quality of right renal arterial images was evaluated by two observers simultaneously (5-scale).The consistency and difference between the two observers were analyzed.The CT values of abdominal aorta,celiac trunk,superior mesenteric artery,common hepatic artery,pancreatic artery and erector spinae,SD values of erector spinae on the level of right renal hilus were measured respectively in both groups.The CT values of abdominal aorta and its main branches,the CNR of abdominal aorta,the volume CT dose index (CTDIvol),dose-length product (DLP) and overall iodine intake in each group were compared.Results The scoring of right renal arterial images in both groups were 5.00 (1.00),the results showed a good consistency (Kappa=0.932,0.911).The CT values of abdominal aorta,superior mesenteric artery,common hepatic artery and pancreatic artery in group A were all more than those of in group B (all P＜0.05).The CNR of group A was higher than that of group B (P＜0.05).The CTDIvoland DLP in group A decreased by 73.36％ and 74.41％ compared with group B.The overall iodine intakes in group A and group B were (46.33±6.43)ml and (84.31±10.71)rnl,respectively.The overall iodine intake of group A decreased by 45.05％ compared with group B.Conclusion For patients with low BMI (≤22 kg/m2),a 70 kVp tube current abdominal CTA scanning can significantly increase the contrast of images of abdominal artery and its branches.Meanwhile,the radiation dose and overall iodine intake can obviously decrease.
ABSTRACT
Objective To explore the impact of pre-setted generation adaptive statistical iterative reconstruction Veo (ASiR-V) on chest CT radiation dose and image quality.Methods The chest model and 120 patients (divided into 6 groups,each n=20) were scanned by GE Revolution CT under the condition of pre-setted ASiR-V weights for 0,20％,40％,60％,80％ and 100％ respectively.The tube voltage was 120 kV,the tube current was automated mAs (Smart mA10-500) technology,the noise index was 11.The dose-length product of each chest model group and patients group were record,the effective dose (ED) of each group was calculated and compared.The image quality among groups through combining the objective CT and standard deviation (SD) values of different organizations (lung tissue,the soft tissue near by spine,the aorta and vertebral body) in chest model and the image subjective rating of patients were compared,and the subjective score of patients' images was also compared among groups.Results With the increase of pre-setted ASiR-V,the ED of chest model and patients reduced as a logarithmic fitting,there are no obvious changes of the CT value and image noise SD value of different organizations in model.The subjective score of mediastinal and pulmonary window was begin to decline at 40％ weighted ASiR-V.The subjective score of mediastinal and pulmonary window descend obviously at 60％ weighted ASiR-V compare to 40％ (P＜0.05).ED of pre-setted 40％ weighted ASiR-V reduced to 57.21％ compared to that of 0 weighted ASiR-V.Conclusion The pre-setted ASiR-V can reduce the radiation dose,and does not affect the objective image quality at the same time.The pre-setted 40 ％ weighted ASiR-V has the highest clinical application value due to the radiation dose can be obviously reduced with ensuring the image quality,which can meet the demand of diagnosis.