title: Evaluation of blood flow distribution asymmetry and vascular geometry in patients with Fontan circulation using 4-D flow MRI.
abstract: BACKGROUND
  Asymmetrical caval to pulmonary blood flow is suspected to cause complications in patients with Fontan circulation. The aim of this study was to test the feasibility of 4-D flow MRI for characterizing the relationship between 3-D blood flow distribution and vascular geometry.
  
  
  OBJECTIVE
  We hypothesized that both flow distribution and geometry can be calculated with low interobserver variability and will detect a direct relationship between flow distribution and Fontan geometry.
  
  
  METHODS
  Four-dimensional flow MRI was acquired in 10 Fontan patients (age: 16 ± 4 years [mean ± standard deviation], range: 9-21 years). The Fontan connection was isolated by 3-D segmentation to evaluate flow distribution from the inferior vena cava (IVC) and superior vena cava (SVC) to the left and right pulmonary arteries (LPA, RPA) and to characterize geometry (cross-sectional area, caval offset, vessel angle).
  
  
  RESULTS
  Flow distribution results indicated SVC flow tended toward the RPA while IVC flow was more evenly distributed (SVC to RPA: 78% ± 28 [9-100], IVC to LPA: 54% ± 28 [4-98]). There was a significant relationship between pulmonary artery cross-sectional area and flow distribution (IVC to RPA: R(2)=0.50, P=0.02; SVC to LPA: R(2)=0.81, P=0.0004). Good agreement was found between observers and for flow distribution when compared to net flow values.
  
  
  CONCLUSIONS
  Four-dimensional flow MRI was able to detect relationships between flow distribution and vessel geometry. Future studies are warranted to investigate the potential of patient specific hemodynamic analysis to improve diagnostic capability.
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA. kelly.jarvis@u.northwestern.edu.|Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, USA. kelly.jarvis@u.northwestern.edu.
authors.forename: Kelly
authors.initials: K
authors.lastname: Jarvis
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.
authors.forename: Susanne
authors.initials: S
authors.lastname: Schnell
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia
authors.affiliation: Department of Radiology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Ramona
authors.initials: R
authors.lastname: Lorenz
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rose
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.
authors.forename: Varun
authors.initials: V
authors.lastname: Chowdhary
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.
authors.forename: James
authors.initials: J
authors.lastname: Carr
authors.affiliation: Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.|Division of Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Robinson
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.|Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Rigsby
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.|Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
mesh_terms: D000293:Adolescent; D002648:Child; D005240:Feasibility Studies; D005260:Female; D018729:Fontan Procedure; D006330:Heart Defects, Congenital / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging; D014683:Vena Cava, Superior / Q000254:growth & development; D055815:Young Adult
keywords: Cardiovascular magnetic resonance; Children; Congenital heart disease; Fontan; Four-dimensional flow magnetic resonance imaging; Heart