SPECT imaging in the emergency department for chest pain: Rest vs stress

Abstract

Background: Prior work has shown that rest SPECT imaging in patients with chest pain in emergency department [ED] has a very high negative predictive value for short-term events. A normal rest study, however, can not exclude CAD. The additive value of a follow-up stress study is not well known. Materials and Methods: During a 4 year period, 1408 patients had rest Tc-99m Tetrofosmin SPECT imaging. Of those, 1237 patients had normal rest images and out of those, 599 patients had a follow-up stress study on a separate day [exercise or adenosine]. All studies were done with electrocardiographic gating and with and without attenuation correction. Results: There were 171 abnormal rest perfusion images among the entire study group (1408 patients with chest pain)[ 12%] and 105 abnormal stress studies among the 599 patients who underwent stress testing [18%] [p= 0.002 vs abnormal rest study alone]. Overall, there were 291 patients with abnormal rest or stress perfusion or abnormal left ventricular function defined as ejection fraction <45% [p=0.05 vs abnormal perfusion alone at rest]. Conclusion: Rest gated SPECT images alone underestimated the magnitude of existing CAD in patients presenting to Emergency Department with chest pain. A stress study increases the detection rate of CAD and could be the first and only imaging test in selected patients.