title: [Preliminary study of improved quality of computed tomographic angiography on tumor blood supply arteries of gastrointestinal tract malignant tumors with low tube voltage and low concentration contrast medium].
abstract: OBJECTIVE
  To assess the image quality of gastrointestinal tract malignant tumors arteries using low tube voltage, low contrast medium concentration and 50% adaptive statistical iterative reconstruction (ASiR) algorithm.
  
  
  METHODS
  A total of 58 patients with pathologically confirmed gastrointestinal tract malignant tumors and body mass index (BMI) under 22 kg/m² undergoing computed tomography (CT) scanning during March-December 2013. They were randomly divided into group A (270 mgI/ml of contrast medium, 80 kVp tube voltage scanning and 50% ASiR; 21 males and 11 females with an age range of 40-90 years) and group B (350 mgI/ml of contrast medium, 120 kVp routine tube voltage; 22 males and 4 females with an age range of 40-76 years). The inter-group differences of age and gender ratio were compared with Mann-Whitney U and Fisher exact tests respectively. Two independent radiologists reviewed reconstructions and separated the reconstructed image into 5 points according to image quality. The CT value of tumor blood supplying artery (CT1 value) and fat in anterior abdominal wall (SD value) were measured and image noise, contrast-to-noise ratio (CNR) and figure of merit (FOM) calculated. The interobserver variation was estimated by weighted kappa statistics and intra-class correlation coefficients (ICC) test. The point of image quality of two groups was compared by Mann-Whitney U test. The paired Student t test was used to compare the inter-group differences in CT1, SD, CNR, FOM and CT dose index (CTDIvol).
  
  
  RESULTS
  No inter-group difference existed in patient age or gender ratio. The consistency of two radiologists was excellent (kappa value > 0.80; ICC value > 0.75). The subjective image quality scores of tumor blood supplying arteries showed no inter-group difference (P = 0.09). The tumor blood supply arteries CT value, CNR and FOM of group A (459 ± 69 HU, 20.2 ± 3.3 and 85 ± 37) were significantly higher than those of group B (250 ± 42 HU, 9.3 ± 1.9 and 9 ± 4) (both P < 0.01). The SD value of group A (20.0 ± 1.7) was obviously lower than that of group B (22.4 ± 3.2) (P < 0.01). And the CTDIvol of group A (5.2 ± 1.2 mGy) was obviously lower than that of group B (13.5 ± 4.7 mGy) (P < 0.01).
  
  
  CONCLUSIONS
  For patients of BMI ≤ 22 kg/m², low tube voltage and low contrast medium concentration scan condition with 50% ASiR algorithm is feasible for acquiring better quality image and ensuring significant reduction in effective dose.
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China; Email: cjr.liuailian@vip.163.com.
authors.forename: Ailian
authors.initials: A
authors.lastname: Liu
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Huizhi
authors.initials: H
authors.lastname: Cao
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Shifeng
authors.initials: S
authors.lastname: Tian
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Jinghong
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Heqing
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Renwang
authors.initials: R
authors.lastname: Pu
authors.affiliation: Department of Radiology, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography; D001158:Arteries; D015992:Body Mass Index; D003287:Contrast Media; D005260:Female; D005770:Gastrointestinal Neoplasms; D006801:Humans; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media