INS and hyperinsulinism: A main strength of the present study is the use of gold standard methods to assess myocardial and whole-body metabolism by cardiac FDG PET combined with the euglycemic-hyperinsulinemic clamp technique, which allows the valuation of insulin-stimulated myocardial glucose uptake under uniform experimental conditions of euglycemia and physiological hyperinsulinemia by removing the confounding factor of different circulating glucose and insulin levels [14, 55].