Usefulness of gated myocardial perfusion SPECT imaging soon after exercise to identify postexercise stunning in patients with single-vessel coronary artery disease

Abstract

Tc-99m gated SPECT imaging soon after exercise is superior to conventional late imaging to discriminate patients with single-vessel disease and postexercise stunning.

Influence of the postexercise acquisition delay on the detection of functional abnormalities in sestamibi-gated SPECT

“…The clinical implication of our results for the routine practice of a busy nuclear medicine laboratory is that a prolonged delay in the postexercise acquisition or its repetitionfor instance, because of major patient movement-does not preclude the detection of exercise-induced functional abnormalities in most cases. This conclusion somewhat challenges the study by Toba et al, 3 who proposed a very early acquisition (10 minutes after tracer injection) of gated SPECT to obtain reliable detection of ischemic functional changes. The differences between the two studies could partly explain this disagreement.…”

“…[15][16][17][18] Nowadays, gated SPECT allows the measurement of LV volumes and EF, and therefore the functional consequences of ischemia can be directly appreciated. [1][2][3] In the studies about poststress gated SPECT functional changes, the time interval between tracer injection and poststress imaging ranged from 15 minutes to more than 60 minutes, and there was no direct comparison between different delays. 1,2,[19][20][21][22][23][24][25][26][27][28] Recently, Toba et al 3 reported that in patients with single-vessel CAD, a very early (10 minutes) poststress gated SPECT study was superior to the usual 30-and 50-minute intervals to identify transient decreases in EF in the subjects with stress-induced ischemia, and they confirmed the relationship between severity of ischemia and degree of functional impairment.…”

“…[1][2][3] According to the model of myocardial stunning, it would be desirable to perform the poststress gated SPECT acquisition early after exercise, because this could increase the likelihood of identifying transient functional abnormalities. 3 On the other hand, by use of the technetiumlabeled perfusion agents, early imaging might be disadvantageous in terms of image quality, mainly because of high subdiaphragmatic activity. 4 Furthermore, an important advantage of these tracers over thallium 201 is the possibility of repeating the scan acquisition in case of major patient motion or other causes of inadequate image quality, without the risk of changes in perfusion.…”

“…The duration of stress-induced functional impairment is controversial, [5][6][7][8][9][10] and scanty data are available about the time course of functional changes after exercise in gated SPECT poststress images. 3 It is therefore unclear what the rate of missed functional ischemic changes would be if the poststress acquisition had to be delayed (eg, because of persistent high subdiaphragmatic activity) or repeated (eg, because of excessive patient motion). To clarify this issue, we compared the functional parameters obtained in 2 consecutive gated SPECT poststress acquisitions and examined their relationship with the extent and severity of perfusion abnormalities, using the perfusion pattern for reference.…”

Technetium‐99m‐sestamibi Redistribution after Exercise Stress Test Identified by a Novel Cardiac Gamma Camera: Two Case Reports

“…Several studies also suggested that the magnitude of stress-induced functional changes (transient decrease in ejection fraction, changes in end-diastolic and end-systolic volumes, and the degree of transient ischemic dilation) may be more pronounced on myocardial perfusion images acquired early after stress. 6,7 Even though all of these studies were relatively small and some did not show statistically significant differences between early and delayed imaging, they suggested that earlier imaging might improve the sensitivity of CAD detection, especially in cases where ischemic defects are mild. Earlier imaging, should it prove useful, will also be more cost-effective and will increase the turnover of patients in a busy nuclear cardiology department, decreasing the workload at the same time.…”