Background: Gated single photon emission tomography (SPET) may simultaneously assess perfusion and function of the myocardium.
Aim: To evaluate the relationship between the presence of ischaemia during an adenosine stress test and the changes in left ventricular (LV) function obtained after stress and at rest with gated SPET by using adenosine same-day stress and rest protocol.
Methods: The study population consisted of twenty eight patients. The gated SPET acquisition was performed both after adenosine vasodilatation and at rest with a protocol as follows: 300 MBq of Tc-99m Myoview at stress, 700 MBq reinjection at rest and double head gamma camera. Global left ventricular ejection fraction (LVEF) and end-diastolic and end-systolic volumes (EDV, ESV) as well as the regional wall motion reversibility from post-stress and resting scan were analysed.
Results: Wall motion disturbances were present in the stress study in 15 patients with subsequent improvement in 14 cases on the rest scans. An independent evaluation of the perfusion data revealed significant reversible myocardial ischaemia in 18 patients and negative result in 10. There was a significant difference between EDV change in patients with or without ischaemia (p<0.02). The post-stress LVEF and ESV were significantly different from those measured at rest. Reversible regional wall motion impairment indicated the presence of significant reversible myocardial ischaemia with an 88% positive predictive value (70% and 75% for sensitivity and specificity, respectively).
Conclusions: The post-stress LVEF with gated SPET may not reflect true resting measurements. The qualitative assessment of regional wall motion reversibility shows better correlation with the ischaemic scan pattern than the difference in the LVEF and may be helpful in assessing the significance of reversible myocardial ischaemia.