title: High-pitch Helical Dual-source Computed Tomographic Pulmonary Angiography: Comparing Image Quality in Inspiratory Breath-hold and During Free Breathing.
abstract: OBJECTIVE
  The purpose of this study was to compare qualitative and quantitative image parameters of dual-source high-pitch helical computed tomographic pulmonary angiography (CTPA) in breath-holding (BH) versus free-breathing (FB) patients.
  
  
  METHODS
  Ninety-nine consented patients (61 female individuals; mean age±SD, 49±18.7 y) were randomized into BH (n=45) versus FB (n=54) high-pitch helical CTPA. Patient characteristics and CTPA radiation doses were analyzed. Two readers assessed for pulmonary embolism (PE), transient interruption of contrast, and respiratory and cardiac motion. The readers used a subjective 3-point scale to rate the pulmonary artery opacification and lung parenchymal appearance. A single reader assessed mean pulmonary artery signal intensity, noise, contrast, signal to noise ratio, and contrast to noise ratio.
  
  
  RESULTS
  PE was diagnosed in 16% BH and 19% FB patients. CTPAs of both groups were of excellent or acceptable quality for PE evaluation and of similar mean radiation doses (1.3 mSv). Transient interruption of contrast was seen in 5/45 (11%) BH and 5/54 (9%) FB patients (not statistically significant, P=0.54). No statistically significant difference was noted in cardiac, diaphragmatic, and lung parenchymal motion. Lung parenchymal assessment was excellent in all cases, except for 5/54 (9%) motion-affected FB cases with acceptable quality (statistically significant, P=0.03). No CTPA was considered nondiagnostic by any of the readers. No objective image quality differences were noted between both groups (P>0.05).
  
  
  CONCLUSIONS
  High-pitch helical CTPA acquired during BH or in FB yields comparable image quality for the diagnosis of PE and lung pathology, with low radiation exposure. Only a modest increase in lung parenchymal artifacts is encountered in FB high-pitch helical CTPA.
authors.affiliation: *Cardiothoracic Imaging Unit, Radiology Department, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah, Western Region †Radiology Department, King Faisal Specialist Hospital and Research Center, Riyadh, Central Region, Saudi Arabia ‡Depatrment of Radiology and Division of Cardiology, Saint Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Amr M
authors.initials: AM
authors.lastname: Ajlan
authors.forename: Salma
authors.initials: S
authors.lastname: Binzaqr
authors.forename: Dalia A
authors.initials: DA
authors.lastname: Jadkarim
authors.forename: Lamia G
authors.initials: LG
authors.lastname: Jamjoom
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
mesh_terms: D062485:Breath Holding; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012119:Respiration; D059629:Signal-To-Noise Ratio; D036542:Tomography, Spiral Computed