title: CT angiography of the neck: value of contrast medium dose reduction with low tube voltage and high tube current in a 64-detector row CT.
abstract: OBJECTIVE
  To evaluate the feasibility of a low-dose contrast medium protocol for 64-detector row computed tomography angiography (CTA) of the neck using a low-tube-voltage/high-tube-current setting.
  
  
  METHODS
  A phantom study was performed using 64-detector row spiral CT at multiple tube voltage and current settings. Iodine contrast medium attenuation curves were acquired by processing and used to select the best contrast medium-to-noise ratio (CNR). A prospective clinical study was then performed on 84 patients requiring neck CTA. Patients were randomly divided into two groups of 42. Group A was examined using the conventional imaging protocol (120 kV, 400 mAs) and group B was examined at 80 kV and 600 mAs along with a 50% reduction in contrast medium dose. The CT dose index-volume (CTDI(vol)), background noise (BN), and CNR were measured and statistically analysed. Various image quality criteria were evaluated by two senior radiologists using a qualitative five-point scale.
  
  
  RESULTS
  Comparing group B with A, CTDIvol decreased by 54% (B: 27.48 mGy, A: 59.11 mGy), however, the CNR increased by 50%. The mean attenuation, which was caused by venous streak artefacts, was significantly lower in group B than A. Qualitative image analysis found that all criteria were significantly better for group B than A.
  
  
  CONCLUSIONS
  At 64-detector row spiral CT, the low-tube-voltage/high-tube-current with low-dose contrast medium protocol was superior to the conventional protocol regarding radiation dose, venous streak artefacts, and image quality, and is feasible for CTA of the neck.
authors: Clinical Medical College, Yangzhou University, Radiology Department, Subei People's Hospital of Jiangsu Province, Yangzhou, China.
authors: W
authors: W
authors: Xia
authors: Clinical Medical College, Yangzhou University, Radiology Department, Subei People's Hospital of Jiangsu Province, Yangzhou, China. Electronic address: wujingtao5688@163.com.
authors: J-T
authors: JT
authors: Wu
authors: Radiology Department, Huashan Hospital, Fudan University, Shanghai, China.
authors: X-R
authors: XR
authors: Yin
authors: Clinical Medical College, Yangzhou University, Radiology Department, Subei People's Hospital of Jiangsu Province, Yangzhou, China.
authors: Z-J
authors: ZJ
authors: Wang
authors: Clinical Medical College, Yangzhou University, Radiology Department, Subei People's Hospital of Jiangsu Province, Yangzhou, China.
authors: H-T
authors: HT
authors: Wu
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D016477:Artifacts; D001822:Body Burden; D003287:Contrast Media / Q000008:administration & dosage*; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D009333:Neck / Q000473:pathology* / Q000528:radiation effects; D019047:Phantoms, Imaging; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000295:instrumentation; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D007455:Iodine