title: Nonrigid registration improves MRI T2 quantification in heart transplant patient follow-up.
abstract: BACKGROUND
  To evaluate the use of a nonrigid registration technique for detecting acute heart transplant rejection by MRI T2 quantification.
  
  
  METHODS
  Myocardial T2 quantification was achieved in 279 consecutive examinations from 78 different patients. The protocol consisted of 10 successive black-blood fast spin echo sequences with varying echo times, and a postprocessing based on image registration and exponential fitting. An automatic nonrigid registration method was applied to correct for myocardium misalignment. Finally T2 values were compared with those obtained with a conventional rigid registration followed by manual correction.
  
  
  RESULTS
  Nonrigid registration was feasible in 98% of the datasets and was judged of higher quality compared with conventional processing (P < 0.001). No significant difference was found in the clinical outcome (average septal T2 ) between nonrigid and conventional registration (P = 0.66). Interobserver variability was improved with 95% limits of agreement of 2.7 ms (against 3.7 ms with conventional registration). The quality of T2 fitting, as assessed by the coefficient of determination R(2) , was significantly improved (P < 0.001).
  
  
  CONCLUSIONS
  Nonrigid registration improves T2 quantification in heart-transplant patient follow-up.
authors.affiliation: U947, Inserm, Nancy, France.|Imagerie Adaptative Diagnostique et Interventionnelle, Université de Lorraine, Nancy, France.
authors.forename: Freddy
authors.initials: F
authors.lastname: Odille
authors.affiliation: CRM2, UMR CNRS 7036, Université De Lorraine, Nancy, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Escanyé
authors.affiliation: Centre for Medical Imaging, University College London, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Atkinson
authors.affiliation: U947, Inserm, Nancy, France.|Imagerie Adaptative Diagnostique et Interventionnelle, Université de Lorraine, Nancy, France.|Department of Cardiology, CHU Strasbourg, Strasbourg, France.
authors.forename: Laurent
authors.identifier: http://orcid.org/0000-0002-5194-1762
authors.initials: L
authors.lastname: Bonnemains
authors.affiliation: U947, Inserm, Nancy, France.|Imagerie Adaptative Diagnostique et Interventionnelle, Université de Lorraine, Nancy, France.|CIC-IT 1433, CHU Nancy, Nancy, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Felblinger
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000209:etiology* / Q000473:pathology*; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D016896:Treatment Outcome
keywords: T2 mapping; cardiac transplantation; image registration