Diagnostic efficacy of SPECT/CT MPI and CMR in children with myocarditis caused by different infection sources.

This study aimed to analyze the diagnostic efficacy of ^99mTc-methoxy isobutyl isonitrile (MIBI) single photon emission tomography (SPECT/CT) myocardial perfusion imaging (MPI) and cardiac magnetic resonance imaging (CMR) in children with myocarditis caused by different infection sources and provide an imaging reference basis for clinical diagnosis and treatment. In total, 232 children diagnosed with myocarditis were retrospectively divided into five groups according to the different infection sources: viral infection (group A), bacterial infection (group B), viral combined with bacterial infection (group C), viral combined with mycoplasma infection (group D), and bacterial combined with mycoplasma infection (group E). A chi-square test and ANOVA were used to analyze the difference between SPECT/CT MPI and CMR in the diagnosis of myocarditis in children according to their categorical infection source group, including the impact of the average daily hospital costs (a=0.05). The positive rates of SPECT/CT in groups A and D were higher than those of CMR, and the positive rates of SPECT/CT in groups C and E were lower than those of CMR, with statistically significant differences (P < 0.05). The SPECT/CT ischemic lesions were located in the anterior wall, or the anterior wall combined with other walls of the left ventricle in 69.5% of patients. SPECT/CT MPI had no effect on the average daily hospitalization cost (P > 0.05); however, the average daily hospitalization cost of CMR-negative patients in group D was higher than that of CMR-positive patients, and it was statistically significant in groups C and E (P < 0.05). In groups A and D, the use of ^99mTc-MIBI SPECT/CT MPI was preferred for diagnosing myocarditis. The detection rate of CMR was higher in groups C and E. SPECT/CT MPI findings of ischemic segments were mostly found in the anterior wall. The results of CMR diagnosis affected the average daily hospitalization cost among patients with different infection sources; however, SPECT/CT had no such effect. These findings denote a potential targeted approach to myocarditis diagnosis in pediatric patients based on source of infection.