CORONARY-ARTERY STENOSIS AND OCCLUSION - VALUE OF TC-99M-MIBI SPECT

The aim of this study was to evaluate and validate a new quantificatio n method for Tc-99m-sestamibi single photon emission computed tomograp hic (SPECT) myocardial imaging based on a four-slice analysis method a nd to check the functional results of percutaneous transluminal corona ry angioplasty (PTCA). Using the calculated pathological area of the s cintigram as an index for myocardial ischaemia, the overall sensitivit y was 81-90% and the overall specificity was 74-98%. Analysis of varia nce of the repeated measurements revealed good reproducibility (coeffi cient of variation 8.4%). A significant correlation was found between the size of the exercise-induced perfusion defects and the degree of c oronary stenosis. The comparison of radionuclide ventriculography and the perfusion image in 27 patients revealed a good correlation between the resting global ejection fraction and myocardial perfusion, but th ere was no correlation during exercise, indicating a dissociation betw een myocardial perfusion and function during exercise conditions in pa tients with coronary artery disease (CAD). Patients with total coronar y occlusions showed more resting defects than patients with partial st enoses. Both groups benefit from PTCA or re-opening of chronic coronar y occlusion, respectively. Exercise-induced myocardial ischaemia signi ficantly decreased, and in 36% of the patients with previous myocardia l infarction a significant reduction of the size of the resting perfus ion defects occurred. In conclusion, our quantification method is suit able for the accurate non-invasive diagnosis of CAD, and for the follo w-up of the invasive treatment of coronary artery stenoses and occlusi ons.