Definitive diagnosis of acute myocardial infarction early in the process is often difficult. An imaging agent that localized quickly and specifically in areas of acute necrosis could provide this critical diagnostic information. To determine whether imaging with 99mTc-labeled D-glucaric acid (GLA) could provide this information, we imaged a group of patients presenting with symptoms suggestive of acute infarction.
Methods: Twenty-eight patients presenting to the emergency department with symptoms highly suggestive of acute infarction were injected with 99mTC-GLA and imaged about 3 h later.
Results: The sensitivity of lesion detection was remarkably time dependent. Fourteen patients with acute infarction injected within 9 h of onset of chest pain had positive scans, even in the presence of persistent occlusion. The remaining 14 patients had negative scans. Nine patients with negative scans had acute infarction but were injected more than 9 h after onset of chest pain. The final diagnosis in the remaining 5 patients was unstable angina (3 injected <9 h and 2 injected >9 h after onset of chest pain). Six patients were reinjected with 99mTc-GLA 4-6 wk after their initial study to determine whether persistent positive scans occurred with this agent. All 6 had negative scans.
Conclusion: This study suggests that 99mTc-GLA localizes in zones of acute myocardial necrosis when injected within 9 h of onset of infarction.