title: Three-dimensional dual-phase whole-heart MR imaging: clinical implications for congenital heart disease.
abstract: OBJECTIVE
  To identify which rest phase (systolic or diastolic) is optimum for assessing or measuring cardiac structures in the setting of three-dimensional (3D) whole-heart imaging in congenital heart disease (CHD).
  
  
  METHODS
  The study was approved by the institutional review board; informed consent was obtained. Fifty children (26 male and 24 female patients) underwent 3D dual-phase whole-heart imaging. Cardiac structures were analyzed for contrast-to-noise ratio (CNR) and image quality. Cross-sectional measurements were taken of the aortic arch, right ventricular (RV) outflow tract (RVOT) and pulmonary arteries. Normally distributed variables were compared by using paired t tests, and categorical data were compared by using Wilcoxon signed-rank test.
  
  
  RESULTS
  Mean CNR and image quality were significantly (all P < .05) greater in systole for the right atrium (CNR, 8.9 vs 7.5; image quality, 438 vs 91), left atrium (CNR, 8.0 vs 5.3; image quality, 1006 vs 29), RV (CNR, 10.6 vs 8.2; image quality, 131 vs 23), LV (CNR, 9.4 vs 7.7; image quality, 125 vs 28), and pulmonary veins (CNR, 6.2 vs 4.9; image quality, 914 vs 32). Conversely, diastolic CNR was significantly higher in the aorta (9.2 vs 8.2; P = .013) and diastolic image quality was higher for the left pulmonary artery (238 vs 62; P = .007), right pulmonary artery (219 vs 35; P < .001), and for imaging of an area after an arterial stenosis (164 vs 7; P < .001). All aortic arch and RVOT cross-sectional measurements were significantly (P < .05) greater in systole (narrowest point of arch, 70 vs 53 mm(2); descending aorta, 71 vs 58 mm(2); transverse arch, 293 vs 275 mm(2); valvar RVOT, 291 vs 268 mm(2); supravalvar RVOT, 337 vs 280 mm(2); prebifurcation RVOT, 329 vs 259 mm(2)).
  
  
  CONCLUSIONS
  Certain structures in CHD are better imaged in systole and others in diastole, and therefore, the dual-phase approach allows a higher overall success rate. This approach also allows depiction of diameter changes between systole and diastole and is therefore preferable to standard single-phase sequences for the planning of interventional procedures.
authors.affiliation: Division of Imaging Sciences, St Thomas' Hospital, Rayne's Institute, London, England. mohammad.hussain@kcl.ac.uk
authors.forename: Tarique
authors.initials: T
authors.lastname: Hussain
authors.forename: Dirk
authors.initials: D
authors.lastname: Lossnitzer
authors.forename: Hannah
authors.initials: H
authors.lastname: Bellsham-Revell
authors.forename: Israel
authors.initials: I
authors.lastname: Valverde
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Bell
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.forename: Rene M
authors.initials: RM
authors.lastname: Botnar
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Uribe
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Greil
mesh_terms: D000293:Adolescent; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003971:Diastole; D005260:Female; D006330:Heart Defects, Congenital / Q000175:diagnosis*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018709:Statistics, Nonparametric; D013599:Systole