title: Diffuse Myocardial Fibrosis in Children After Heart Transplantations: A Magnetic Resonance T1 Mapping Study.
abstract: BACKGROUND
  It is unclear whether the myocardium undergoes accelerated fibrotic remodeling in children after heart transplantation (HTx).
  
  
  METHODS
  In this prospective study, cardiac magnetic resonance (CMR) studies in 17 patients 1.3 years (median, range 0.03-12.6 years) after HTx (mean age, 9.8 ± 6.2 years; 8 girls) were compared to CMR studies in 9 healthy controls (mean age, 12.4 ± 2.4 years; 4 girls). T1 measurements were performed at a midventricular short axis slice before (ie, native T1 times) and after the application of 0.2 mmol/kg gadopentetate dimeglumine in the interventricular septum, left ventricular (LV) free wall and encompassing the entire LV myocardium. The tissue-blood partition coefficient (TBPC), reflecting the degree of diffuse myocardial fibrosis, was calculated as a function of the ratio of T1 change of myocardium compared to blood. Native T1 times and TBPC were correlated with echocardiographic parameters of diastolic function.
  
  
  RESULTS
  Native T1 times were significantly higher in HTx patients compared to controls in all regions assessed (LV free wall 973 ± 42 vs 923 ± 12 ms; P < 0.005; interventricular septum 1003 ± 31 vs 974 ± 21 ms, P < 0.05; entire LV myocardium 987 ± 33 vs 951 ± 16 ms; P < 0.005) and correlated with LV E/e' as an echocardiographic marker of diastolic dysfunction (r = 0.54, P < 0.05). The TBPC was elevated in the LV free wall (0.45 ± 0.06 vs 0.40 ± 0.03, P < 0.005) and the entire LV myocardium (0.47 ± 0.06 vs 0.43 ± 0.03, P < 0.05).
  
  
  CONCLUSIONS
  Evidence of diffuse myocardial fibrosis and is already present in children after HTx. It appears to be associated with diastolic dysfunction.
authors.affiliation: 1 Division of Cardiology, Department of Pediatrics, Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada. 2 Stollery Children's Hospital, Department of Pediatric Cardiology, Edmonton, Alberta, Canada. 3 Alberta Children's Hospital, Section of Cardiology, University of Calgary, Calgary, Alberta, Canada. 4 Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada. 5 Siemens AG Healthcare Sector, Erlangen, Germany.
authors.forename: Eugénie
authors.initials: E
authors.lastname: Riesenkampff
authors.forename: Ching Kit
authors.initials: CK
authors.lastname: Chen
authors.forename: Paul F
authors.initials: PF
authors.lastname: Kantor
authors.forename: Steven
authors.initials: S
authors.lastname: Greenway
authors.forename: Rajiv R
authors.initials: RR
authors.lastname: Chaturvedi
authors.forename: Shi-Joon
authors.initials: SJ
authors.lastname: Yoo
authors.forename: Andreas
authors.initials: A
authors.lastname: Greiser
authors.forename: Anne I
authors.initials: AI
authors.lastname: Dipchand
authors.forename: Lars
authors.initials: L
authors.lastname: Grosse-Wortmann
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005355:Fibrosis / Q000175:diagnosis / Q000209:etiology; D005500:Follow-Up Studies; D016027:Heart Transplantation / Q000379:methods*; D006801:Humans; D007223:Infant; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D011183:Postoperative Complications / Q000175:diagnosis*; D011446:Prospective Studies