title: CT angiography of pulmonary embolism using a 64 slice multi-detector scanner.
abstract: BACKGROUND
  Multi-detector computed tomography (MDCT) has already been the first line investigation method for diagnosis of pulmonary embolism (PE). Reducing the amount of contrast medium used during CT scanning could decrease the incidental rate of adverse reactions. Our study amied to evaluate the image quality of pulmonary arteries using 64 slice multi-detector CT with small volumes of contrast media injection.
  
  
  METHODS
  Forty nonconsecutive patients without PE or other lung diseases were randomly assigned to two groups. Group A underwent CT scanning with 16 x 1.25 mm collimation and a 70 ml contrast injection, while group B had CT with 64 x 0.625 mm collimation and 20 ml of contrast injection. Two readers independently depicted the segmental and subsegmental pulmonary arteries. Reasons we could not analyze the pulmonary artery or that led to misdiagnosis of pulmonary embolism were evaluated, including the degree of contrast enhancement of the main pulmonary artery, and factors that caused misdiagnosis of PE (flow-related artifacts, partial volume artifact, beam-hardening artifacts and enhancement of pulmonary vein). The independent samples t-test, Mann-Whitney U test and Pearson chi-square test were applied.
  
  
  RESULTS
  There were no significant differences in image quality of segmental and subsegmental arteries between the two groups. No significant difference was found for factors that made pulmonary arteries non-analyzable or in the misdiagnosis of PE, except the degree of contrast enhancement.
  
  
  CONCLUSIONS
  64 x 0.625 mm collimation with 20 ml contrast injection could depict the pulmonary arteries well.
authors.affiliation: Department of Radiology, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing 100034, China. docqin730@sina.com
authors.forename: Nai-shan
authors.initials: NS
authors.lastname: Qin
authors.forename: Xue-xiang
authors.initials: XX
authors.lastname: Jiang
authors.forename: Jian-xing
authors.initials: JX
authors.lastname: Qiu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhu
authors.forename: Ji-chen
authors.initials: JC
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014463:Ultrasonography
chemical_list: D003287:Contrast Media