To study whether myocardial single-photon emission computed tomography (SPECT)/CT with radiation absorption correction (RAC) versus fractional flow reserve (FFR) may be used to assess the hemodynamic relevance of borderline coronary stenosis in patients with coronary heart disease (CHD).The investigation enrolled 70 patients (50 men and 20 women; mean age 57 ± 5 years) diagnosed as having CHD verified by clinical instrumental studies, in whom coronary angiography (CA) estimating FFR revealed 50 to 70% coronary stenosis; then all the patients underwent SPECT/CT using a two-day rest/exercise (bicycle ergometer) protocol; the total injected radiotracer activity was 370-900 MBq 99mTc-MIBI depending on body weight.A standard 17-segment scheme was employed to calculate the SDS index, borderline stenosis detected by CA was considered hemodynamically significant at SDS ≥ 4 in one of the 17 segments, which corresponded to one of the major coronary artery, which was compared by the authors ith FFR. At SDS ≥ 4, the sensitivity and specificity of SPECT/CT were shown to be 96.7 and 90.6%, respectively.Quantitative analysis of borderline stenosis by SPECT/CT with RAC increases its specificity and sensitivity in estimating the functional significance of borderline coronary stenosis.