title: Efficacy of 'breath holding at ease' during CT pulmonary angiography in the improvement of contrast enhancement in pulmonary arteries.
abstract: BACKGROUND
  The aim of this study is to assess whether breath-hold at ease by patients during the CT pulmonary angiography (CTPA) will improve contrast enhancement in pulmonary arteries.
  
  
  METHODS
  Retrospective review was conducted on 51 consecutive CTPA studies undertaken in the traditional method of patients taking deep inspiration and breath-hold immediately prior to scanning, and subsequently 75 consecutive CTPA studies with patients breathing-holding at ease immediately prior to and during the scanning. Attenuation values in pulmonary arteries of different anatomical levels in both groups were measured in Hounsfield unit (HU). Results were compared between the two groups.
  
  
  RESULTS
  The mean attenuation value in pulmonary arteries including pulmonary trunk, main and proximal pulmonary arteries calculated in HU in the 'deep inspiration and breath-hold' group was 327 HU (95% confidence interval: 315 to 339 HU). The mean attenuation value in pulmonary arteries in the 'breath hold at ease' group was calculated to be 390 HU (95% confidence interval: 381 to 399 HU); that is, an overall 17.95% increase (P-value < 0.0001) in attenuation value in this group.
  
  
  CONCLUSIONS
  By asking patients to breath-hold at ease instead of taking deep inspiration and breath hold prior to CTPA scan can effectively improve contrast enhancement in pulmonary arteries, therefore producing a higher-quality CT pulmonary angiography scan.
authors.affiliation: Southern Health Network, Monash Medical Centre, Clayton, Australia. jourenayyli@gmail.com
authors.forename: YeYuan Jourena
authors.initials: YJ
authors.lastname: Li
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Lau
authors.forename: Nicholas
authors.initials: N
authors.lastname: Ardley
authors.forename: Theodore
authors.initials: T
authors.lastname: Lau
mesh_terms: D000368:Aged; D000792:Angiography / Q000706:statistics & numerical data*; D062485:Breath Holding; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014739:Victoria / Q000453:epidemiology
keywords: CT pulmonary angiography; CTPA; artefact; breath-hold at ease; contrast enhancement