Two-day stress-rest lower limbs perfusion scan in patients referred for myocardial perfusion imaging

Introduction: Peripheral Vascular Disease (PVD) is a major cause of morbidity and is associated with Coronary Artery Disease (CAD). We aimed to perform Lower Limb Perfusion Scan (LLPS) in patients referred for Myocardial Perfusion Imaging (MPI) and estimate prevalence of PVD in subgroups with normal and abnormal MPI results. We also compared quantitative indices of LLPS in patients with and without abnormal MPI results with semi-quantitative QPS indices. Methods: 120 patients referred for MPI entered the study. Exercise or dipyridamole infusion was used as stress modality. After 99mTc-MIBI injection at peak stress, whole body posterior views and planar images from thighs and calves were obtained. Gated MPI was done subsequently. Rest phase was performed the following day. LLPS was analyzed visually and quantitatively. Results: In patients with abnormal and normal MPI results, LLPS revealed 22.58% and 1.92% prevalence of PVD in exercise subgroup (P-Value=0.004) and 50.00% and 10.52% in dipyridamole subgroup (P-Value= 0.013), respectively. Both of these different prevalence were statistically significant. In exercise subgroup, mean ranks of Stress Index (Is) for all lower limb regions were statistically significantly greater in patients with normal MPI result. Also, among patients who had ischemia in exercise-rest MPI, negative correlations were seen between Is and Rest Index (Ir) of all regions and QPS quantitative indices. Conclusion: LLPS with 99mTc-MIBI, combined with MPI is a feasible method to detect lower limbs ischemia, especially in patients with abnormal MPI results. Correlating quantitative indices of LLPS with MPI-QPS also reflect coexistence of CAD and PVD.