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.