title: Assessment of myocardial edema and area at risk in a rat model of myocardial infarction with a faster T2 mapping method.
abstract: BACKGROUND
  The common T2 mapping is not suitable for the use in rat heart with high heart rate, unless data are acquired in multiple cardiac cycles.
  
  
  OBJECTIVE
  To evaluate a simplified T2 mapping method for faster assessment of myocardial edema and area at risk in a rat model of myocardial infarction.
  
  
  METHODS
  The simplified T2 mapping method (TR/TE, 1500 ms/10, 20, 30 ms) was implemented at a 7.0T MRI system. The accuracy of T2 mapping was compared with a standard T2 mapping method (TR, 2500 ms, 16 TEs equally spaced from 11 ms to 176 ms) in thigh muscles in rats (n = 6) and a phantom. This method was further evaluated in normal rats (n = 8) and rats with myocardial infarction (n = 8). Late gadolinium enhancement images were also acquired in the rats with myocardial infarction.
  
  
  RESULTS
  T2 values of simplified T2 mapping in the muscles and phantom were 27.3 ± 2 ms and 26.5 ± 1.1 ms, which were similar to the T2 values obtained by the standard T2 mapping method (28.1 ± 1.4 ms, P > 0.05; 26.9 ± 1.7 ms). No significant difference in T2 distribution (different segments and slices from base to apex) in the whole heart was found in normal rats (25.6 ± 3.3 ms, P > 0.05). The mean T2 value in the myocardial edema regions of myocardial infarction rats (37 ± 4.9 ms) was significantly higher than that of the normal rats (25.6 ± 3.3 ms, P < 0.001). The T2 value in the myocardial infarction core of myocardial infarction rats (39.9 ± 3.6 ms) was significantly higher than that of area at risk (34.7 ± 2.9 ms, P < 0.001).
  
  
  CONCLUSIONS
  The simplified myocardial T2 mapping is technically feasible and accurate, and can readily detect myocardial edema and area at risk in rats with high heart rate.
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, PR China Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Xia
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, PR China.
authors.forename: Xi
authors.initials: X
authors.lastname: Lu
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, PR China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, PR China.
authors.forename: Jichun
authors.initials: J
authors.lastname: Liao
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, MO, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, PR China gaofabao@yahoo.com zhengj@wustl.edu.
authors.forename: Fabao
authors.initials: F
authors.lastname: Gao
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004487:Edema / Q000473:pathology*; D004562:Electrocardiography; D005240:Feasibility Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal; D009203:Myocardial Infarction / Q000473:pathology*; D019047:Phantoms, Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D013848:Thigh
keywords: Cardiac; Edema; Experiment Investigations; Ischemia/Infarction; MR imaging