Abstract 2329: Discrepancy In Coronary Imaging; Luminal Stenosis Versus Atherosclerosis In Relation To Myocardial Perfusion
Purpose: Preliminary comparisons between myocardial perfusion imaging (MPI) and Multi-Slice Computed Tomography (MSCT) suggest a large discrepancy between an abnormal MSCT study and MPI results. How these contradictory findings should be interpreted remain at present unclear. The purpose of the study therefore was to perform, in addition to MPI and MSCT, invasive imaging, not only of the coronary lumen (using coronary angiography) but also of the vessel wall (using intravascular ultrasound, IVUS).
Methods: A total of 45 patients underwent both MSCT and MPI followed by invasive coronary angiography in combination with IVUS imaging. Quantitative coronary angiography (QCA) and IVUS measurements were performed of the severest lesion, while MSCT studies were classified as either normal or abnormal (indicating the presence of atherosclerosis). Stress-rest gated MPI was performed to evaluate myocardial perfusion.
Results: Results are summarized in Figure 1⇓. Briefly, a good agreement between modalities was observed in patients with abnormal MPI. However, a normal MPI study was in most patients associated with an abnormal MSCT study despite only minimal luminal stenosis on QCA (26.5%). Considerable plaque burden (58%) however was revealed by IVUS imaging, yet without luminal compromise (average minimal luminal area 5.7mm2).
Conclusion: Observations between MPI, MSCT and invasive coronary angiography may appear initially contradictory as an abnormal MSCT is frequently obtained in patients with normal perfusion and invasive angiograms. In these patients, the detected atherosclerosis may be located mainly in the vessel wall, rather than extending into the coronary lumen.