Comparison of left ventricular ejection fraction from gated 4 hr-rest Tl-201 in stress-rest thallium-201 SPECT with radionuclide ventriculography (RV)

Objectives Aim of this prospective study was to compare the left ventricular ejection fraction (LVEF) obtained on Gated 4hr-rest thallium-201 myocardial perfusion single photon emission computed tomography (Tl-201 GSPECT) with those obtained by resting Radionuclide Ventriculography (RV) in patients with known or suspected coronary artery disease (CAD).

Methods Eighty-two consecutive patients underwent gated Tl-201 stress-rest myocardial perfusion SPECT. At peak stress, 3-3.5 mCi (111-130 MBq) Tl-201 was administered intravenously. Post-stress gated SPECT acquisition was performed on a dual-head camera using LEAP collimator, sixty-four projections (20 seconds/projection) acquired over 180 degrees. Gating was performed with 8 frames per cardiac cycle, using a 100% beat acceptance window. Rest gated acquisition was performed 4 hrs after stress using the same acquisition protocol. Transverse slices were reconstructed using filtered back projection (Butterworth filter: 0.45,5). The stress and rest gated Tl-201 images were processed with Siemens E-SOFT autocardiac processor and LVEF were evaluated using Emory Cardiac Toolbox. The LVEF of same patients was also assessed on the Radionuclide Ventriculography for comparison within a week.

Results There was good linear correlation with RV values and Gated 4hr-rest Tl-201 SPECT images for LVEF. The Pearson's correlation co-efficient (r value) for LVEF between the two methods was =0.91. Bland Altmann plot also showed close agreement between the LVEF derived by two methods.

Conclusions These results suggest that the gated 4hr-rest Tl-201 images gives reliable LVEF compared to RV and can be used in routine clinical practice