title: Coronary enhancement for prospective ECG-gated single R-R axial 320-MDCT angiography: comparison of 60- and 80-mL iopamidol 370 injection.
abstract: OBJECTIVE
  The objective of our study was to evaluate the difference in coronary enhancement provided by 60 versus 80 mL of contrast medium (370 mg I/mL) for prospectively ECG-gated single-heartbeat axial 320-MDCT.
  
  
  METHODS
  We retrospectively evaluated 108 consecutive 320-MDCT angiography studies. Group 1 (n = 36) received 60 mL of an iodinated contrast medium and group 2 (n = 72), 80 mL. All patients were imaged with a standardized protocol: iopamidol 370 followed by 40 mL of saline, both administered at a rate of 6 mL/s. Two imagers subjectively assessed image quality throughout the coronary arteries. Region-of-interest attenuation (HU) measurements were performed in the aorta plus the proximal and distal coronary arteries.
  
  
  RESULTS
  Subjective analysis of all coronary segments showed slightly better image quality for group 2. Patients in group 1 had significantly (p < 0.05) lower mean attenuation values for the individual coronary vessels. Nevertheless, 96.7% of all coronary segments in the group 1 patients had an attenuation of greater than 300 HU; when analysis was limited to group 1 patients with a body mass index of greater than 30, 92.8% of the segments were more than 300 HU, and all segments measured more than 250 HU.
  
  
  CONCLUSIONS
  An injection protocol based on 60 mL of iopamidol (370 mg I/mL) for prospectively ECG-gated wide-area detector single-heartbeat coronary CT angiography (CTA) has less coronary enhancement than a protocol based on 80 mL. However, using 60 mL, more than 96% of coronary segments had sufficient enhancement (i.e., > 300 HU), supporting the general use of 60-mL protocols for clinical wide-area detector coronary CTA.
authors.affiliation: Department of Radiology, Applied Imaging Science Laboratory, Brigham and Women's Hospital & Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors.forename: Kanako K
authors.initials: KK
authors.lastname: Kumamaru
authors.forename: Michael L
authors.initials: ML
authors.lastname: Steigner
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Soga
authors.forename: Jason
authors.initials: J
authors.lastname: Signorelli
authors.forename: Arash
authors.initials: A
authors.lastname: Bedayat
authors.forename: Kimberly
authors.initials: K
authors.lastname: Adams
authors.forename: Dimitris
authors.initials: D
authors.lastname: Mitsouras
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
mesh_terms: D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D016009:Chi-Square Distribution; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol