title: Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation.
abstract: BACKGROUND
  T2mapping is a magnetic resonance imaging technique measuring T2relaxation time, which increases with the myocardial tissue water content. Myocardial edema is a component of acute cellular rejection (ACR) after heart transplantation. This pilot study compares in heart transplantation recipients a novel high resolution 3-dimensional (3D) T2-mapping technique with standard 2-dimensional (2D) T2-mapping for ACR detection.
  
  
  METHODS
  Consecutive asymptomatic patients (n = 26) underwent both 3D T2mapping and reference 2D T2mapping magnetic resonance imaging on the day of endomyocardial biopsy (EMB). 3D T2maps were obtained at an isotropic spatial resolution of 1.72 mm (voxel volume 5.1 mm3). 2D and 3D maps were matched anatomically, and maximum segmental T2values were compared blinded to EMB results. In addition, all 3D T2maps were rendered as 3D images and inspected for foci of T2elevation.
  
  
  RESULTS
  T2values of segments from 2D and reformatted 3D T2maps agreed (p > 0.5). The highest 2D segmental T2values were 49.9 ± 4.0 ms (no ACR = 0R, n = 18), 48.9 ± 0.8 ms (mild ACR = 1R, n = 3), and 65.0 ms (moderate ACR = 2R). Rendered 3D T2maps of cases with 1R showed foci with significantly elevated T2signal (T2= 58.2 ± 3.6 ms); 5 cases (28%) in the 0R group showed foci with increased T2values (>2 SD above adjacent tissue) that were not visible on the 2D T2maps.
  
  
  CONCLUSIONS
  This pilot study in a small cohort suggests equivalency of standard segmental analysis between 3D and 2D T2-mapping. 3D T2mapping provides a spatial resolution that permits detection of foci with elevated T2in patients with mild ACR.
authors.affiliation: Department of Radiology, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.
authors.forename: Ruud B
authors.initials: RB
authors.lastname: van Heeswijk
authors.affiliation: Department of Radiology, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.; Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland.
authors.forename: Davide
authors.initials: D
authors.lastname: Piccini
authors.affiliation: Department of Cardiac Surgery, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.
authors.forename: Piergiorgio
authors.initials: P
authors.lastname: Tozzi
authors.affiliation: Institute of Pathology Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.
authors.forename: Samuel
authors.initials: S
authors.lastname: Rotman
authors.affiliation: Cardiology, Department of Medical Specialties, University Hospital Geneva, Geneva, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Meyer
authors.affiliation: Center for Cardiac Magnetic Resonance (CRMC) Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.; Cardiology, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.
authors.forename: Juerg
authors.initials: J
authors.lastname: Schwitter
authors.affiliation: Department of Radiology, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
authors.affiliation: Cardiology, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Hullin