title: The initial experience of the upper abdominal CT angiography using low-concentration contrast medium on dual energy spectral CT.
abstract: OBJECTIVE
  To investigate the feasibility of using Spectral CT imaging with low contrast medium in abdominal CT angiography (CTA).
  
  
  METHODS
  70 consecutive patients (40 men, 42.6 ± 20.4 years; 30 women, 46.7 ± 18.8 years) with suspected abdominal focal lesions were referred to CTA exam. They were randomly assigned into two groups. Group A: 35 patients underwent conventional CT scan of Tube voltage 120 kVp, automatic current modulation with a Noise Index of 12, ASIR 30%, and injected with Iohexol (350 mgI/ml). Group B: 35 patients underwent Spectral CT Imaging, with Tube current of 600 mA, injected with Iodixanol (270 mgI/ml). The optimal mono-energy keV was achieved using the optimal contrast noise ratio in abdominal aorta at the renal artery level relative to the erector spine muscle. Both groups were injected with an injection rate of 3.5 ml/s, and a contrast volume of 1.5 ml/kg body weight. The Hounsfield units (HU) and noise of the bilateral renal arteries and muscle of both groups, as well as the optimal monochromatic image set of Group B were measured. Two radiologists assessed all images with a 5-points scale. CTDIvol and DLP were recorded. Data were analyzed using student t test.
  
  
  RESULTS
  The total iodine intake of Group B was 28% lower than that of Group A. The CNR of abdomen artery, celiac trunk, superior mesenteric artery, and renal artery in spectral group (at the best mono-energy of 53.0 keV) were higher than those in conventional CTA group (p < 0.001). The subjective image quality score of spectral CTA group was also rated higher than conventional CTA group (p < 0.001). CTDIvol, DLP, and effective dose of spectral group were all lower than conventional group, but there were no significant differences (p > 0.05).
  
  
  CONCLUSIONS
  With 28% contrast medium reduction and reduced radiation dose, CT angiography using spectral imaging and lower concentration contrast agent provided better image quality than conventional CTA.
authors.affiliation: Shanxi Province Tumor Hospital (The Affiliated Tumor Hospital of Shanxi Medical University), Taiyuan, China. 337501266@qq.com.
authors.forename: Lei
authors.identifier: http://orcid.org/0000-0002-7389-547X
authors.initials: L
authors.lastname: Xin
authors.affiliation: Shanxi Province Tumor Hospital (The Affiliated Tumor Hospital of Shanxi Medical University), Taiyuan, China. yxtbean@126.com.
authors.forename: Xiaotang
authors.initials: X
authors.lastname: Yang
authors.affiliation: GE Healthcare, Beijing, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Huang
authors.affiliation: Shanxi Province Tumor Hospital (The Affiliated Tumor Hospital of Shanxi Medical University), Taiyuan, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Du
authors.affiliation: Shanxi Province Tumor Hospital (The Affiliated Tumor Hospital of Shanxi Medical University), Taiyuan, China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Shanxi Province Tumor Hospital (The Affiliated Tumor Hospital of Shanxi Medical University), Taiyuan, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Shanxi Province Tumor Hospital (The Affiliated Tumor Hospital of Shanxi Medical University), Taiyuan, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Hou
authors.affiliation: Shanxi Academy of Medical Sciences & Shanxi Dayi Hospital, Taiyuan, China.
authors.forename: Jinfang
authors.initials: J
authors.lastname: Gao
mesh_terms: D000328:Adult; D000368:Aged; D000792:Angiography; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D002445:Celiac Artery / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008638:Mesenteric Arteries / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011860:Radiography, Abdominal; D012077:Renal Artery / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007472:Iohexol
keywords: CT angiography; Computed tomography; Upper abdomen; X-ray