title: Comparison of respiratory motion artifact from craniocaudal versus caudocranial scanning with 64-MDCT pulmonary angiography.
abstract: OBJECTIVE
  The purpose of this article is to compare respiratory motion artifact between craniocaudal versus caudocranial 64-MDCT acquisition for CT pulmonary angiography.
  
  
  METHODS
  We retrospectively reviewed 100 consecutive emergency radiology CT pulmonary angiography examinations acquired on a 64-MDCT scanner between April 2007 and February 2008 for two groups of patients: caudocranial acquisition (mean age, 50.5 years; range, 16.6-84.2 years; mean [+/- SD] scan duration, 9.1 +/- 1.1 seconds) and craniocaudal acquisition (mean age, 56.5 years; range, 22.4-94.2 years; mean scan duration, 7.1 +/- 0.9 seconds). Two blinded readers reviewed randomized coronal reformatted images in lung windows and scored the severity of respiratory motion artifact in the upper, middle, and lower lung zones on a 4-point scale (0, no artifact; 1, mild; 2, moderate; and 3, severe). Caudocranial versus craniocaudal differences in artifact severity were assessed using the concordance statistic. The Student's t test was used to compare incidence of diagnostically limited examinations containing moderate or severe artifact.
  
  
  RESULTS
  There were no statistically significant differences between scans obtained in the caudocranial versus craniocaudal scan direction in any lung zone or on the basis of the most severe artifact score per patient (p > 0.3). There were no significant differences between the groups with regard to the incidence of diagnostically limited scans (p > 0.25) containing either moderate or severe artifact.
  
  
  CONCLUSIONS
  Craniocaudal CT pulmonary angiography multislice acquisition with a slight decrease in scan duration had a similar degree of respiratory motion artifact to caudocranial scanning, performing equivalently in all lung zones and on an overall patient-by-patient basis.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Boston, MA 02115, USA. cwu6@partners.org <cwu6@partners.org>
authors.forename: Christopher
authors.initials: C
authors.lastname: Wu
authors.forename: Aaron
authors.initials: A
authors.lastname: Sodickson
authors.forename: Tianxi
authors.initials: T
authors.lastname: Cai
authors.forename: Noah A
authors.initials: NA
authors.lastname: Levit
authors.forename: Michael L
authors.initials: ML
authors.lastname: Steigner
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Ledbetter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D016477:Artifacts; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011857:Radiographic Image Interpretation, Computer-Assisted; D012119:Respiration; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide