title: Imaging quality evaluation of low tube voltage coronary CT angiography using low concentration contrast medium.
abstract: OBJECTIVE
  To compare the image quality of prospectively ECG-gated low voltage coronary computed tomography angiography (CTA) with an administration of low concentration contrast medium.
  
  
  METHODS
  A total of 101 patients, each with a heart rate below 65 beats per minute (BPM), underwent a prospectively ECG-gated axial scan in CT coronary angiography on a 64-slice CT scanner. All patients were allocated in three groups (group A: n=31, 80 kVp, 300 mgI/ml; group B: n=34, 100 kVp, 300 mgI/ml; group C: n=36, 120 kVp, 370 mgI/ml). The CT attenuation values of aortic root (AR), left main coronary artery (LMA), right main coronary artery (RMA) and chest subcutaneous fat tissue were measured. The contrast-to-noise ratio (CNR) of AR, LMA and RMA were calculated according to the formulas below. The values of computed tomography dose index (CTDI) and dose-length product (DLP) were recorded. Image quality was assessed on a 5-point scale. The results were compared using the one-way ANOVA and rank sum tests.
  
  
  RESULTS
  The values of CNR and SNR for vessels in group A and group B were not significantly different from group C (each p > 0.05). The effective radiation dose in group A (1.51 ± 0.70 mSv) and group B (2.59 ± 1.24 mSv) were both lower than group C (4.92 ± 2.82 mSv) (each p < 0.05). There was no significant difference among the image quality scores of group A (4.10 ± 0.41), group B (3.90 ± 0.48) and group C (4.04 ± 0.36) (each P > 0.05).
  
  
  CONCLUSIONS
  Low tube voltage coronary CT angiography using low concentration contrast medium does not affect the imaging quality for assessing the coronary arteries compared with high voltage coronary CT angiography using high concentration contrast medium. Meanwhile low concentration contrast medium allowed 47-69% of radiation dose reduction.
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Chengzhong
authors: C
authors: Zhang
authors: Department of Interventional Radiology, Weifang People's Hospital, Weifang, Shandong, People's Republic of China.
authors: Yuejun
authors: Y
authors: Yu
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Zaixian
authors: Z
authors: Zhang
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Qingguo
authors: Q
authors: Wang
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Linfeng
authors: L
authors: Zheng
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Yan
authors: Y
authors: Feng
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Zhiguo
authors: Z
authors: Zhou
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Guixiang
authors: G
authors: Zhang
authors: Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
authors: Kangan
authors: K
authors: Li
mesh_terms: D000368:Aged; D055424:Cardiac-Gated Imaging Techniques; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards
chemical_list: D003287:Contrast Media