title: Coronary CTA using scout-based automated tube potential and current selection algorithm, with breast displacement results in lower radiation exposure in females compared to males.
abstract: OBJECTIVE
  To evaluate the effect of automatic tube potential selection and automatic exposure control combined with female breast displacement during coronary computed tomography angiography (CCTA) on radiation exposure in women versus men of the same body size.
  
  
  METHODS
  Consecutive clinical exams between January 2012 and July 2013 at an academic medical center were retrospectively analyzed. All examinations were performed using ECG-gating, automated tube potential, and tube current selection algorithm (APS-AEC) with breast displacement in females. Cohorts were stratified by sex and standard World Health Organization body mass index (BMI) ranges. CT dose index volume (CTDIvol), dose length product (DLP) median effective dose (ED), and size specific dose estimate (SSDE) were recorded. Univariable and multivariable regression analyses were performed to evaluate the effect of gender on radiation exposure per BMI.
  
  
  RESULTS
  A total of 726 exams were included, 343 (47%) were females; mean BMI was similar by gender (28.6±6.9 kg/m(2) females vs. 29.2±6.3 kg/m(2) males; P=0.168). Median ED was 2.3 mSv (1.4-5.2) for females and 3.6 (2.5-5.9) for males (P<0.001). Females were exposed to less radiation by a difference in median ED of -1.3 mSv, CTDIvol -4.1 mGy, and SSDE -6.8 mGy (all P<0.001). After adjusting for BMI, patient characteristics, and gating mode, females exposure was lower by a median ED of -0.7 mSv, CTDIvol -2.3 mGy, and SSDE -3.15 mGy, respectively (all P<0.01).
  
  
  CONCLUSIONS
  We observed a difference in radiation exposure to patients undergoing CCTA with the combined use of AEC-APS and breast displacement in female patients as compared to their BMI-matched male counterparts, with female patients receiving one third less exposure.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Harshna
authors.initials: H
authors.lastname: Vadvala
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Phillip
authors.initials: P
authors.lastname: Kim
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mayrhofer
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Pianykh
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Mannudeep
authors.initials: M
authors.lastname: Kalra
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Ghoshhajra
keywords: Coronary computed tomography angiography (CCTA); breast displacement; female; radiation exposure