title: Computed tomography pulmonary angiography using a 20% reduction in contrast medium dose delivered in a multiphasic injection.
abstract: OBJECTIVE
  To evaluate the feasibility of reducing the dose of iodinated contrast agent in computed tomography pulmonary angiography (CTPA).
  
  
  METHODS
  One hundred and twenty-seven patients clinically suspected of having pulmonary embolism underwent spiral CTPA, out of whom fifty-seven received 75 mL and the remaining seventy a lower dose of 60 mL of contrast agent. Both doses were administered in a multiphasic injection. A minimum opacification threshold of 250 Hounsfield units (HU) in the main pulmonary artery is used for assessing the technical adequacy of the scans.
  
  
  RESULTS
  Mean opacification was found to be positively correlated to patient age (Pearson's correlation 0.4255,P< 0.0001) and independent of gender (male:female, 425.6vs450.4,P= 0.34). When age is accounted for, the study and control groups did not differ significantly in their mean opacification in the main (436.8vs437.9,P= 0.48), left (416.6vs419.8,P= 0.45) or the right pulmonary arteries (417.3vs423.5,P= 0.40). The number of sub-optimally opacified scans (the mean opacification in the main pulmonary artery < 250 HU) did not differ significantly between the study and control groups (7vs10).
  
  
  CONCLUSIONS
  A lower dose of iodine contrast at 60 mL can be feasibly used in CTPA without resulting in a higher number of sub-optimally opacified scans.
authors.affiliation: Mitchell Chen, Jamal A Abdulkarim, Department of Radiology, George Eliot Hospital NHS Trust, Nuneaton, Warwickshire CV10 7DJ, United Kingdom.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Chen
authors.affiliation: Mitchell Chen, Jamal A Abdulkarim, Department of Radiology, George Eliot Hospital NHS Trust, Nuneaton, Warwickshire CV10 7DJ, United Kingdom.
authors.forename: Gaith
authors.initials: G
authors.lastname: Mattar
authors.affiliation: Mitchell Chen, Jamal A Abdulkarim, Department of Radiology, George Eliot Hospital NHS Trust, Nuneaton, Warwickshire CV10 7DJ, United Kingdom.
authors.forename: Jamal A
authors.initials: JA
authors.lastname: Abdulkarim
keywords: Acute kidney disease; Computed tomography pulmonary angiography; Contrast dose; Contrast dose reduction; Contrast induced nephropathy; Contrast safety; Multiphasic injection