title: Pulmonary 64-MDCT angiography with 30 mL of IV contrast material: vascular enhancement and image quality.
abstract: OBJECTIVE
  The objective of our study was to determine whether vascular enhancement and image quality can be preserved in pulmonary CT angiography (CTA) performed on a 64-MDCT scanner with 30 mL of IV contrast material.
  
  
  METHODS
  This retrospective matched-cohort study compared image quality of pulmonary CTA performed using 30 mL of IV contrast material versus 100 mL of IV contrast material. CT images of 50 patients (46 men, four women; mean age, 66 years) who underwent pulmonary CTA on a 64-MDCT scanner using a low dose (30 mL) of iodixanol 320 and another 50 patients (49 men, one woman; mean age, 65 years) who underwent pulmonary CTA using a regular dose (100 mL) of contrast material during the same time period were selected for review. The 30- and 100-mL pulmonary CTA studies were retrospectively evaluated by two thoracic radiologists in random order. Attenuation values were recorded over the main, right main, selected lobar, segmental, and subsegmental pulmonary arteries. Image quality was also subjectively assessed using visual scores on a scale from 1 (nondiagnostic) to 5 (excellent).
  
  
  RESULTS
  The average attenuation measurements of the main, right main, selected lobar, segmental, and subsegmental pulmonary arteries were 260, 262, 280, 316, and 338 HU, respectively, on the 30-mL studies and 313, 301, 316, 344, and 349 HU, respectively, on the 100-mL studies. The average visual score was 4.0 for both the 30- and 100-mL groups. A visual score of 4 or 5 was given to 82% of studies in the 30-mL group and 78% of studies in the 100-mL group.
  
  
  CONCLUSIONS
  Contrast agent dose for pulmonary CTA using a 64-MDCT scanner can be significantly reduced without compromising diagnostic image quality.
authors.affiliation: Department of Radiology, Division of Thoracic Imaging and Interventions, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Carol C
authors.initials: CC
authors.lastname: Wu
authors.forename: Edward W
authors.initials: EW
authors.lastname: Lee
authors.forename: Robert D
authors.initials: RD
authors.lastname: Suh
authors.forename: Barton S
authors.initials: BS
authors.lastname: Levine
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Barack
mesh_terms: D000368:Aged; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol