CLINICAL VALIDATION OF AUTOMATIC QUANTITATIVE DEFECT SIZE IN REST TECHNETIUM-99M-SESTAMIBI MYOCARDIAL PERFUSION SPECT

We examined the relationships of automatic quantitative perfusion defe ct size and defect severity to rest left ventricular ejection fraction and semiquantitative visual sestamibi defect size in rest Tc-99m-sest amibi SPECT in 40 consecutive patients with a history of myocardial in farction more than 30 days prior to testing. The purpose of this inves tigation was to validate the use of automatic quantitative rest sestam ibi SPECT as a clinical measure of assessing relative infarction size. Methods: All patients received 20-30 mCi of Tc-99m-sestamibi followed by SPECT imaging. Quantitative defect analysis used previously develo ped resting normal limits and an automatic Version of a commercially a vailable quantitative program (CEqual). Semiquantitative visual defect interpretation used a 20 segment/scan and five-point scoring analysis , First-pass (FP) radionuclide ventriculography (RVG) and gated sestam ibi perfusion SPECT were each performed in 31 patients. Results: LVEF assessed by FP RVG was 37% +/- 15% (range 14%-62%) and 37% +/- 16% (ra nge 12%-63%) by gated perfusion SPECT with high linear correlation (r = 0.96, n = 22) between the two methods. Myocardial perfusion defect s ize was 24% +/- 15% of LV (range 0%-50%) and defect severity was 1103 +/- 864 (range 0 to 2825) by automatic quantitative rest sestamibi. Pe rfusion defect size and defect severity both had close correlations wi th LVEF by FP RVG (r = -0.78, r = -0.86) and by gated perfusion SPECT (r = -0.75, r = -0.79). High linear correlations were observed between quantitative defect size and summed visual score of segments with sco re greater than or equal to 2 (r = 0.82) and the number of visually ab normal segments (r = 0.77), as well as between defect severity and vis ual summed rest score (r = 0.86) and the number of visually abnormal s egments (r = 0.76). Conclusion: Quantitation of rest sestamibi SPECT d efect extent and severity using automatic CEqual correlates well with rest LVEF and with semiquantitative expert Visual analysis. Results of this study define a strong relationship between measurements of Tc-99 m-sestamibi perfusion defect as measured by an automatic software prog ram and global loft ventricular function. The automatic quantitative p rogram appears to be a useful measure of assessing infarct size in pat ients with remote myocardial infarction.