title: Cardiovascular magnetic resonance tagging of the right ventricular free wall for the assessment of long axis myocardial function in congenital heart disease.
abstract: BACKGROUND
  Right ventricular ejection fraction (RV-EF) has traditionally been used to measure and compare RV function serially over time, but may be a relatively insensitive marker of change in RV myocardial contractile function. We developed a cardiovascular magnetic resonance (CMR) tagging-based technique with a view to rapid and reproducible measurement of RV long axis function and applied it in patients with congenital heart disease.
  
  
  METHODS
  We studied 84 patients: 56 with repaired Tetralogy of Fallot (rTOF); 28 with atrial septal defect (ASD): 13 with and 15 without pulmonary hypertension (RV pressure > 40 mmHG by echocardiography). For comparison, 20 healthy controls were studied. CMR acquisitions included an anatomically defined four chamber cine followed by a cine gradient echo-planar sequence in the same plane with a labelling pre-pulse giving a tag line across the basal myocardium. RV tag displacement was measured with automated registration and tracking of the tag line together with standard measurement of RV-EF.
  
  
  RESULTS
  Mean RV displacement was higher in the control (26 ± 3 mm) than in rTOF (16 ± 4 mm) and ASD with pulmonary hypertension (18 ± 3 mm) groups, but lower than in the ASD group without (30 ± 4 mm), P < 0.001. The technique was reproducible with inter-study bias ± 95% limits of agreement of 0.7 ± 2.7 mm. While RV-EF was lower in rTOF than in controls (49 ± 9% versus 57 ± 6%, P < 0.001), it did not differ between either ASD group and controls.
  
  
  CONCLUSIONS
  Measurements of RV long axis displacement by CMR tagging showed more differences between the groups studied than did RV-EF, and was reproducible, quick and easy to apply. Further work is needed to assess its potential use for the detection of longitudinal changes in RV myocardial function.
authors.affiliation: Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
authors.forename: Sylvia S M
authors.initials: SS
authors.lastname: Chen
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keegan
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Dowsey
authors.forename: Tevfik
authors.initials: T
authors.lastname: Ismail
authors.forename: Ricardo
authors.initials: R
authors.lastname: Wage
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Guang-Zhong
authors.initials: GZ
authors.lastname: Yang
authors.forename: David N
authors.initials: DN
authors.lastname: Firmin
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Kilner
mesh_terms: D000328:Adult; D006348:Cardiac Surgical Procedures; D016022:Case-Control Studies; D005260:Female; D006330:Heart Defects, Congenital / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006352:Heart Ventricles / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008131:London; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013318:Stroke Volume; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D016278:Ventricular Function, Right; D055815:Young Adult