Evaluating Change in LVEF with Stress 99m Tc-MIBI Imaging; does it Impact on Perfusion Data?
Myocardial perfusion imaging (MPI) is established in evaluating coronary disease. New rapid acquisition protocols allow early assessment of left ventricular function (LVEF) post-stress. Previous trials show increased sensitivity to detect multi-vessel disease with changes in LVEF. We aimed to identify a correlation between the amount of ischaemia and changing LVEF post stress and to see if they offer complimentary information.
Method: 100 patients (pts) referred for clinically indicated studies (74 exercise/26 dipyridamole) with interpretable MPI and LVEF were reviewed. All underwent a standard one-day rest-stress 7 minute gated 99m Tc-MIBI protocol using FLASH 3D reconstruction. Results were analysed semi-quantitatively by blinded readers. A standard 17-segment model determined summed stress score (SSS), rest score (SRS) and difference score (SDS) for each study (0=normal). The difference between stress and rest LVEF (dEF) was calculated. Pts were subdivided into two groups. Group I (n=62) LVEF increased post stress while Group II (n=38) LVEF did not.
Results:
Group I II p
SSS 2.5 6.1 <.0001
SRS 1.4 3.8 <.0001
SDS 1.1 2.3 <.0001
There was good correlation between SDS and dEF (p<0.0001). Pts in Group II were more likely to have high SDS. Of 8 pts in Group II with normal MPI, all had low pre-test likelihood, normal range LVEF and no significant clinical suspicion at follow-up.
Conclusion: Early post-stress LVEF is easily obtained and dEF correlates well with the presence and the amount of reversible ischaemia. However, in our small cohort, we did not identify pts where dEF provided additional information to MPI.