CAN WE RELY ON TC-99(M)-SESTAMIBI GATED TOMOGRAPHIC MYOCARDIAL PERFUSION IMAGING TO QUANTIFY LEFT-VENTRICULAR FUNCTION - A COMPARATIVE-STUDY WITH CLASSICAL ISOTOPIC TECHNIQUES FOR THE MEASUREMENT OF EJECTION FRACTION

The assessment of left ventricular ejection fraction is an important e lement in the evaluation of cardiac performance, and one of the most c ommonly performed tests in nuclear cardiology. The aim of this study w as to evaluate the accuracy and reliability of ejection fraction value s calculated from EGG-gated myocardial perfusion single photon emissio n tomography (GSPET) in comparison with standard scintigraphic methods . Eight-frame gated SPET was recorded 60-90 min after the injection of Tc-99(m)-sestamibi at rest. The ejection fraction was calculated usin g a semi-automatic edge-detection technique based upon a threshold-sea rching method and compared with values obtained from first-pass (FPRNA ) or equilibrium radionuclide angiography (ERNA) in 60 and 40 patients respectively with a broad range of ejection fraction values. Very goo d reproducibility was noted, with an inter-and intra-observer variabil ity of -0.2+/-3.5% (range -7.6 to 6.9%, r=0.97) and -0.2+/-2.2% (range -5.9 to 3.5%, r=0.99) respectively. Similarly, a high concordance was found between GSPET and FPRNA and between GSPET and ERNA over the ran ge of ejection fraction values (13 to 77%), the mean (+/-S.D.) differe nce being 0.8+/-3.8% (r=0.97, P=N.S.) and 0.03+/-5.3% (r=0.94, P=N.S.) respectively. Applying the Bland-Altman plot, no systematic bias of o ne method related to the other was observed, even at extreme ejection fraction values. Gated myocardial perfusion SPET with a Tc-99(m) trace r thus offers a unique opportunity to quantify cardiac performance and perfusion simultaneously and non-invasively.