Magnetic Resonance Imaging in Cardiac Syndrome X

BACKGROUND: Cardiac syndrome X is a subject with yet unsettled etiology and management. Conventional investigations have not been able to establish that chest pain is due to myocardial ischemia. Magnetic resonance imaging has higher resolution and is more accurate for detecting ischemia. AIMS AND OBJECTIVES: To establish subendocardial ischemia as the cause of chest pain in cardiac syndrome X by virtue of stress perfusion cardiac MRI. METHODS: Contrast enhanced cardiac MRI was performed in 15 cases and 7 matched controls both at rest and during a six minute infusion of adenosine. Both visual and quantitive analysis were performed. In quantitative analysis both myocardial perfusion index and myocardial perfusion reserve index was measured. RESULTS: There was a significant increase in myocardial perfusion in both subendocardium as well as in subepicardium in both cases as well as in controls upon stress with adenosine. In controls the subendocardial perfusion index rose from 0.13 0.3 to 0.18 .03 and in the subepicardium from 0.12 .02 to 0.18 .03. In patients with cardiac syndrome X subendocardial perfusion index rose from 0.14 .03 to 0.19 .03 and subepicardial perfusion index rose from 0.13+.03 to 0.19 .03. Visual analysis showed short lasting subendocardial dark rim artificats in both cases and controls which lasted for only 3 to 5 beats. CONCLUSION: Our cardiovascular MR study of patients with cardiac syndrome X demonstrated significant and almost similar magnitude adenosine induced increase in both subendocardial and subepicardial myocardial perfusion indices in both study as well as control group. We found no evidence of subendocardial ischemia in patients with cardiac syndrome X. JMS 2011;14(2):46-51