Magnetic Resonance Diabetic Cardiac Stress Imaging : MRDIABETICS

Rationale:

The incidence of diabetes is rising constantly. According to the WHO projections, the population of diabetics will double by 2025. In France, the current population of diabetics is estimated at 2.5 millions persons. The cause of death in diabetics involves a cardiovascular condition in approximately 65-80% of the cases. The leading event is myocardial infarction. The prevalence of silent myocardial ischemia (SMI) in diabetics varies widely from 10 to 30%. The prognosis of SMI is closely dependent on the presence or not of angiographically significant coronary artery stenosis - CAS (patients with SMI and CAS>70% show 31% of major cardiac events at 41±24 months vs only 1.4% in patients with SMI and no CAS>70%). It seems therefore important to identify diabetic patients with SMI and CAS especially knowing that endovascular or surgical treatments are available and can potentially improve the prognosis of such patients.

Myocardial Perfusion Scintigraphy (MPS) is widely prescribed to detect coronary stenosis. It has a high sensitivity (90%) but an intermediate specificity (75%), providing a significant amount of false positive cases. Such false positive cases are usually followed with unnecessary coronary angiographies. Myocardial Perfusion Stress MRI (MRI) has been recently developed and shows promising preliminary results (equivalent sensitivity, higher specificity compared to MPS) for the identification of coronary artery stenosis. Few studies directly compare MRI and MPS in the general population, none in the diabetic population.

Principal objective: To evaluate and compare diagnostic performances of MRI and MPS for the diagnosis of coronary insufficiency in diabetic patients free of known coronary disease.

Secondary objective: