Abstract
1448
Introduction: Cardiovascular disease has found to be the leading cause of morbidity and mortality, especially in developing countries like India with a prevalence of 11%. This can be attributed to the high prevalence of risk factors like high levels of blood cholesterol and triglycerides, diabetes, hypertension, obesity etc., all of which have found to independently increase the epicardial fat volume (EFV) which is a known source of pro-inflammatory cytokines in the pericardial region augmenting the formation of atherosclerosis and eventual myocardial infarction. Myocardial perfusion imaging using SPECT.CT is commonly performed non-invasive imaging method to evaluate coronary artery disease (CAD). The low dose CT used for attenuation correction is utilised for calculation of EFV. Materials and Methods: 176 patients with suspicion of CAD are included in the study. All patients underwent physical or adenosine stress with 99mTc-MIBI followed by SPECT.CT acquisition after 30-45 minutes. Rest MPI was done in patients showing perfusion defects on stress imaging. We retrospectively analysed total EFV in 176 records (88 records with normal perfusion and 88 with reversible perfusion defects). The MPI images in reversible ischemic group are analysed semiquantitatively and summed difference score (SDS) are recorded. In the low dose CT images threshold of epicardial fat detection was set between -30 HU to -190 HU and software-based quantification of EFV was done in the Siemens multimodality workstation.
Results: Median EFV in scans with normal perfusion was found to be 74.46ml (32.92ml - 211.51ml), and median EFV in scans with reversible ischemia was 92.94ml (43.70ml - 207.53ml) with a median SDS of 5.00 (1.0 - 27). In 16 scans with reversible perfusion defects associated with infarcts in other segments, median EFV was found to be 101.71 ml (range of 63.03 ml to 156.46 ml) with SDS mean of 7.50 (SD = 6.20). Reversible perfusion defects with or without associated infarcts have demonstrated an EFV (median = 92.94ml) when compared to patients with a normal myocardial perfusion (median = 74.64ml) (p < 0.001).
Conclusions: Our results have demonstrated increased epicardial fat volume in patients with the presence of active reversible ischemia compared to that of the normal perfusion on myocardial perfusion scintigraphy (p<0.001) suggesting a potential role of myocardial perfusion SPECT/CT to evaluate the EFV for risk stratification of suspected coronary artery disease.