Comparison of Epicardial Fat Volume between Patients with Normal Perfusion and Reversible Perfusion Abnormalities on Myocardial Perfusion Imaging.

Purpose Of The Study: Our study purpose was to compare the epicardial fat volume (EFV) in myocardial perfusion imaging single photon emission computed tomography/computed tomography (MPI SPECT/CT) with normal and abnormal perfusion in patients with known or suspected coronary artery disease (CAD).

Materials And Methods: one hundred and seventy-six patients (88 records with normal and 88 with reversible perfusion defects) underwent physical or adenosine stress with Tc-99m MIBI followed by SPECT and low-dose CT for attenuation correction. Rest MPI was done in patients showing perfusion defects on stress imaging. Software-based quantification of EFV was done by manually delineating pericardial contours with epicardial fat threshold set between -30 HU and -190 HU.

Results: Median EFV in scans with normal perfusion was found to be 74.46 ml (32.92-211.51), and with reversible ischemia was 92.94 ml (43.70-207.53) with a median-summed difference score (SDS) of 5.00 (1.0-27). In 15 scans with reversible perfusion defects associated with infarcts in other segments, median EFV was 101.71 ml (63.03-156.46) with mean - SDS of 7.50 (standard deviation = 6.20). Scans with reversible perfusion defects demonstrated an increased EFV (median - 92.94 ml) when compared to scans with a normal perfusion (median = 74.64 ml) ( < 0.001).

Conclusion: Our results demonstrated an increased EFV in scans with presence of active reversible ischemia compared to that of normal perfusion on MPI ( < 0.001) suggesting potential role of cardiac SPECT/CT to evaluate EFV for risk stratification of suspected CAD.