Materials and Methods
This was a cross-sectional study, conducted at the nuclear medicine department of Shohada Tajrish hospital, Tehran, Iran. In total, 63 asymptomatic patients with type 2 DM, referred for check-up or pre-operative cardiac evaluation entered the study. An ethical approval was obtained from Shahid Beheshti Medical University Ethics committee.
Patients were interviewed on the appointed scanning day and informed about the goals of study in detail. A written informed consent was obtained from all patients before enrolment. The inclusion criteria were patients with proven T2DM, aged 35-80 years, ejection fraction (EF) > 50%, normal ECG and life expectancy of more than one year. Patients with any history of valvular heart disease, ischemic heart disease, abnormal renal or hepatic failure, coronary intervention, arrhythmia, perfusion defect on prior MPI scans or wall motion abnormality on prior gated stress SPECT-MPI were excluded. Demographic characteristics of participants were documented in a questionnaire. All patients underwent a two-day rest/stress 99mTc-MIBI gated MPI SPECT, according to the European Association of Nuclear Medicine (EANM) guidelines for MPI scan (13). The rest scan was performed 60 minutes after IV injection of 555 MBq 99mTc-sestamibi. On the day after, myocardial stress was achieved by exercise (Bruce protocol) or Dipyridamole (0.14mg/kg/min over 4 minutes), with 740 MBq 99mTc–sestamibi injected at peak stress. All patients consumed 120 mL whole milk 10 minutes after tracer injection, as per routine. Imaging was performed in both supine and prone positions. SPECT images were acquired with a variable angle dual head Evo-Voxel Siemens gamma camera (64 projections; 25 seconds/projection, matrix 64 * 64, zoom of 1.46, 8-frame gated study, low-energy high resolution collimator, in a noncircular orbit). The images were processed using QPS/QGS and 4DM software and the results were interpreted by a nuclear medicine specialist.