Introduction

Excessive exercise can damage the heart[1].According to the cardiac anatomy of athletes who died suddenly, it was found that their myocardial microcirculation was abnormal, suggesting that myocardial microcirculation disorder may also be one of the risk factors for predicting sudden cardiac death in athletes[2].Therefore, it is very important to understand the myocardial microcirculation of athletes to prevent the occurrence of adverse cardiac events.The first pass perfusion and late gadolinium enhancement (LGE) of Cardiac magnetic resonance imaging (MRI) has unique advantages in identifying myocardial microcirculation disorders and myocardial fibrosis[3], which were unavoidable and require the use of contrast agents to show the lesions, and cannot be used for patients prone to allergies and severe renal insufficiency. In recent years, intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) has been gradually applied in heart diseases[4], it can also reflect myocardial microcirculation disorders without the use of contrast agents and the effect can be comparable to the LGE[5].Therefore, this study intended to evaluate the myocardial microcirculation perfusion state of the athletes through IVIM technology, and attempted to establish a predictive model through IVIM-associated parameters and cardiac function parameters for the possibility of cardiac remodeling and delayed enhancement of the athletes with risk stratification.

Materials and Methods

The study recruited 174 amateur athletes (158 males) and 32 healthy volunteers (13 males) for cardiac MRI. Examinations on a 3.0T MRI scanner (Magnetom Prisma, Siemens Healthcare, Erlangen, Germany) equipped with a 18-channel phase control body coil. The IVIM scanning parameters include b value 0, 20, 50, 100, 200, and 350s/mm2; TR, 300ms;TE, 37ms;layer thickness, 5mm; FOV, 200×200mm2; matrix size, 256×186.The IVIM parameters of the 16 myocardium segments for left ventricle except the apical were measured, including slow apparent diffusion coefficient (ADCslow), fast apparent diffusion coefficient (ADCfast) and perfusion fraction (f).The cardiac function parameters were measured by software cvi42 (cmr 42, v.5.2.2; Circle Cardiovascular Imaging, Calgary, Canada), including end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) , cardiac output (CO), cardiac index (CI), stroke volume (SV) and myocardial mass of the left ventricular (LV) and right ventricular (RV).All data were measured by two cardiovascular diagnostician who had worked for more than 3 years without knowing the clinical information of the subject. Mann Whitney U test was used to compare the IVIM parameters of the athletes and controls. The clinical prediction model for cardiac remodeling and myocardial fibrosis of athletes was established by selecting IVIM-associated parameters and cardiac function parameters, and then the prediction accuracy of the model was evaluated by calculating the overall performance, discrimination ability and calibration.The area under the curve (AUC) of the receiver operating characteristic curve (ROC) was used to show the predictive ability.

Results:

The ADCfast and f value of the athletes were significantly lower than the healthy volunteers｛1.07[0.85,1.38] vs 1.52[0.95,2.58]×10-2mm2/s; 0.22[0.16,0.34] vs 0.46[0.26,0.74], respectively; p<0.05}.When myocardial remodeling and LGE were used as outcome variables, the date of exercise record, cardiac function parameters and IVIM parameters of male athletes were used to establish a predictive model, including weekly exercise time, training years, LVCO, LVCI, the ADCfast value et.al, which achieved good predictive performance, especially ADCfast, with AUC of 0.87 and 0.92, respectively.

Conclusion

The myocardial microcirculation changed in exerciser compared with normal controls. The ADCfast value and cardiac function measured by MRI could noninvasively predicted the possibility of cardiac remodeling or even LGE for risk stratification of athletes.

Acknowledgements

none

References

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