Left Ventricular Functional Changes after Adenosine Vasodilator Stress Evaluated by Gated Single-Photon Emission Computed Tomography

Abstract

Objectives: Gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging is useful in assessing left ventricular (LV) myocardial perfusion and function. This study evaluated the LV functional changes after adenosine vasodilator stress, using gated SPECT. Methods: The study population consisted of 70 patients who underwent adenosine-mediated stress and rest SPECT. All patients underwent coronary angiography. Semi-quantitative assessment of perfusion was analyzed and produced the summed rest score (SRS), the summed stress score (SSS) and the summed difference score (SDS). The global LV function parameters [ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV)] and regional LV function [the summed motion score (SMS) and the summed thickening score (STS)] were quantified by gated SPECT. Results: Patients were divided into 2 groups: group 1 comprised 16 patients with worsening of LVEF (LVEF_rest-LVEF_ado ≥5%), and group 2 comprised the other 54 patients. Compared with group 2, patients in group 1 had a significantly higher SSS and SDS (9.1 ± 6.8 vs. 5.6 ± 4.5 and 6.6 ± 3.8 vs. 3.6 ± 4.0, respectively; p < 0.05) and the severity of coronary artery stenosis was more serious (p < 0.05). Conclusion: Worsening of LVEF after adenosine-induced vasodilator stress, as shown by ^99mTc-MIBI gated SPECT, is a valuable nonperfusion marker of significant CAD.

Thallium‐201 is comparable to technetium‐99m‐sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging

“…What is more interesting and probably more clinically relevant is that significantly higher increase of EF after dipyridamole stress was observed in the normal MPI group than in the positive MPI group by either Tl‐201 or MIBI. In contrast to the documented correlation between decreased stress‐induced LV EF and CAD [8,9], it indicates that increased stress‐induced LV EF could be a significant marker of normal myocardial perfusion. Furthermore, the very close magnitude of stress‐induced change in LV EF between Tl‐201 and MIBI (6.5% vs. 7.0%) may suggest that the effect of dipyridamole stress does not abate despite the much longer lapse between pharmacological stress and imaging of the MIBI protocol.…”