TOMOGRAPHIC AND PLANAR QUANTITATION OF PERFUSION DEFECTS ON TECHNETIUM 99M-LABELED SESTAMIBI SCANS - EVALUATION IN PATIENTS TREATED WITH THROMBOLYTIC THERAPY FOR ACUTE MYOCARDIAL-INFARCTION

Background. Our segmentation algorithm for single-photon emission comp uted tomo-graphic perfusion studies was tested in 244 patients treated by thrombolysis within 5 hours after onset of symptoms. This algorith m uses radial slices to approximate true three-dimensional gradients, determines the apex and basal plane, and creates a perfusion and volum e polar map. Methods and Results. Perfusion defect size was compared w ith enzymatic infarct size and global and regional function. All patie nts underwent rest planar and tomographic Tc-99m-labeled sestamibi sca nning, contrast coronary angiography, and ventriculography 10 to 14 da ys after the start of treatment. Manual correction had to be performed in only 10% of the cases and presented no problems. The correlation c oefficients (r) between planar and relative tomographic perfusion defe cts versus enzymatic infarct size were 0.71 and 0.73. A negative corre lation was found with left ventricular ejection fraction: r = -0.65 an d r = -0.60. A comparable correlation was also found between regional wall motion and perfusion defect size. Most correlations were higher i n the case of anterior infarction. An excellent correlation was found between planar and tomographic defect size (r = 0.83). Conclusions. In most cases, our segmentation algorithm delineates myocardial edges an d basal plane automatically. A good correlation was found between perf usion defect size, enzymatic infarct size, and global and regional ven tricular function.