A 58-year-old woman with hypertension and diabetes presented to the emergency department with exertional right-sided chest pain. Her cardiac biomarkers were negative and her electrocardiogram demonstrated no significant abnormalities. She subsequently underwent pharmacologic stress myocardial perfusion imaging using regadenoson. Her electrocardiogram demonstrated no significant ischemic changes and she only complained of dyspnea following regadenoson infusion. Perfusion images were acquired using the GE millennium MC scanner and processed using Xpress3 cardiac wide beam reconstruction software (UltraSPECT, Ltd.) at an xeleris functional imaging workstation. Review of the rotating raw data revealed breast attenuation artifact but no significant patient motion. Her perfusion imaging revealed a severe defect in the mid-to-distal inferolateral wall that was mostly reversible suggestive of significant ischemia. In addition, there was pronounced dilation of the left ventricle with stress (Figure 1). The patient underwent cardiac catheterization which demonstrated no obstructive coronary artery disease (Figures 2, 3). Upon further analysis of the patient’s history, she had apparently been diagnosed with Prinzmetal angina in the past and had undergone cardiac catheterization eight years prior for similar symptoms and this was normal as well. She was subsequently discharged on appropriate pharmacotherapy and was asymptomatic. Multiple reports have demonstrated coronary vasospasm after use of adenosine for stress testing. However, there is a limited data available in reference to regadenoson, which is a selective A2A adenosine receptor agonist. Recent emerging data demonstrate, however, that regadenoson may also lead to vasospasm as it has similar pharmacologic properties. Our case illustrates severely abnormal myocardial perfusion imaging with reversible regional ischemia and transient ischemic dilation with no obstructive coronary artery disease likely due to regadenoson-induced coronary vasospasm. Therefore, vasospastic heart disease is a potential confounding factor to consider in the interpretation of regadenoson stress MPI and may be clinically relevant in the management of patients with conflicting anatomic and perfusion findings.