Early myocardial damage assessment in dystrophinopathies using ⁹⁹Tc^m-MIBI gated myocardial perfusion imaging

Abstract

Background

Early detection of muscular dystrophy (MD)-associated cardiomyopathy is important because early medical treatment may slow cardiac remodeling and attenuate symptoms of cardiac dysfunction; however, no sensitive and standard diagnostic method for MD at an earlier stage has been well-recognized. Thus, the aim of this study was to test the early diagnostic value of technetium 99m-methoxyisobutylisonitrile (⁹⁹Tc^m-MIBI) gated myocardial perfusion imaging (G-MPI) for MD.

Methods and results

Ninety-one patients underwent ⁹⁹Tc^m-MIBI G-MPI examinations when they were diagnosed with Duchenne muscular dystrophy (DMD) (n=77) or Becker muscular dystrophy (BMD; n=14). ⁹⁹Tc^m-MIBI G-MPI examinations were repeated in 43 DMD patients who received steroid treatments for 2 years as a follow-up examination. Myocardial defects were observed in nearly every segment of the left ventricular wall in both DMD and BMD patients compared with controls, especially in the inferior walls and the apices by using ⁹⁹Tc^m-MIBI G-MPI. Cardiac wall movement impairment significantly correlated with age in the DMD and BMD groups (r_s=0.534 [P<0.05] and r_s=0.784 [P<0.05], respectively). Intermittent intravenous doses of glucocorticoids and continuation with oral steroid treatments significantly improved myocardial function in DMD patients (P<0.05), but not in BMD patients.

Conclusion

⁹⁹Tc^m-MIBI G-MPI is a sensitive and safe approach for early evaluation of cardiomyopathy in patients with DMD or BMD, and can serve as a candidate method for the evaluation of progression, prognosis, and assessment of the effect of glucocorticoid treatment in these patients.

Keywords:

• Duchenne muscular dystrophy
• Becker muscular dystrophy
• dystrophinopathy
• ⁹⁹Tc^m-MIBI
• cardiomyopathy

Acknowledgments

The authors would like to thank Drs Qingbao Tian, Lingge We, and Zhe Zhao for critical comments and valuable suggestions. This work was supported by the grant from the Third Hospital of Hebei Medical University and the Public Health Department of Hebei Medical University.

Disclosure

The authors report no conflicts of interest in this work.