title: Noninvasive assessment of myocardial inflammation by cardiovascular magnetic resonance in a rat model of experimental autoimmune myocarditis.
abstract: BACKGROUND
  Limited availability of noninvasive and biologically precise diagnostic tools poses a challenge for the evaluation and management of patients with myocarditis.
  
  
  RESULTS
  The feasibility of cardiovascular magnetic resonance (CMR) imaging with magneto-fluorescent nanoparticles (MNPs) for detection of myocarditis and its effectiveness in discriminating inflammation grades were assessed in experimental autoimmune myocarditis (EAM) (n=65) and control (n=10) rats. After undergoing CMR, rats were administered with MNPs, followed by a second CMR 24 hours later. Head-to-head comparison of MNP-CMR with T(2)-weighted, early and late gadolinium enhancement CMR was performed in additional EAM (n=10) and control (n=5) rats. Contrast-to-noise ratios were measured and compared between groups. Flow cytometry and microscopy demonstrated that infiltrating inflammatory cells engulfed MNPs, resulting in altered myocardial T(2)* effect. Changes in contrast-to-noise ratio between pre- and post-MNP CMR were significantly greater in EAM rats (1.08 ± 0.10 versus 0.48 ± 0.20; P<0.001). In addition, contrast-to-noise ratio measurement in MNP-CMR clearly detected the extent of inflammation (P<0.001) except for mild inflammation. Compared with conventional CMR, MNP-CMR provided better image contrast (CNR change 8% versus 46%, P<0.001) and detectability of focal myocardial inflammation. Notably, MNP-CMR successfully tracked the evolution of myocardial inflammation in the same EAM rats.
  
  
  CONCLUSIONS
  Magneto-fluorescent nanoparticle CMR permitted effective visualization of myocardial inflammatory cellular infiltrates and distinction of the extent of inflammation compared with conventional CMR in a preclinical model of EAM. Magneto-fluorescent nanoparticle CMR performs best in EAM rats with at least moderate inflammatory response.
authors.affiliation: Division of MR Research, Korea Basic Science Institute, Cheongwon, South Korea.
authors.forename: Hyeyoung
authors.initials: H
authors.lastname: Moon
authors.forename: Hyo Eun
authors.initials: HE
authors.lastname: Park
authors.forename: Jongeun
authors.initials: J
authors.lastname: Kang
authors.forename: Hyunseung
authors.initials: H
authors.lastname: Lee
authors.forename: Chaejoon
authors.initials: C
authors.lastname: Cheong
authors.forename: Yong Taik
authors.initials: YT
authors.lastname: Lim
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Ihm
authors.forename: Ki-Bae
authors.initials: KB
authors.lastname: Seung
authors.forename: Farouc A
authors.initials: FA
authors.lastname: Jaffer
authors.forename: Jagat
authors.initials: J
authors.lastname: Narula
authors.forename: Kiyuk
authors.initials: K
authors.lastname: Chang
authors.forename: Kwan Soo
authors.initials: KS
authors.lastname: Hong
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000473:pathology*; D004195:Disease Models, Animal; D005240:Feasibility Studies; D005682:Gadolinium; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009205:Myocarditis / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology*; D053758:Nanoparticles; D051381:Rats; D011917:Rats, Inbred Lew; D012720:Severity of Illness Index
chemical_list: D005682:Gadolinium