Altered energy metabolism after myocardial infarction assessed by 31P-MR-spectroscopy in humans

Abstract.

The value of ³¹P-magnetic resonance spectroscopy (MRS) as a possible tool to distinguish viable from non-viable tissue after myocardial infarction was analysed in humans. Fifteen patients 3 weeks after anterior myocardial infarction were studied with breath-hold cine MRI and 3D-CSI MRS (1.5 T system). ³¹P-spectra were obtained from infarcted as well as non-infarcted myocardium (voxel size 25 cm³ each). Gold standard for viability was recovery of regional function, as determined by a control MRI 6 months after revascularization. Ten age-matched healthy volunteers served as control group. No significant difference was found between the phosphocreatine to adenosinetriphosphate (PCr/ATP) ratio of volunteers (SD 1.72 ± 0.31) and non-infarcted septal myocardium of patients. Cine MRI demonstrated recovery of regional function in 10 patients, i. e. 10 patients showed viable and 5 non-viable myocardium. In viable myocardium, the PCr/ATP ratio was 1.47 ± 0.38 (non-significant vs volunteers; p > 0.05). In the 5 patients with akinetic myocardium, PCr peaks could not be detected. Therefore, calculation of PCr/ATP ratios was not possible. However, a significant reduction of the ATP signal-to-noise ratio (SNR) was observed (2.92 ± 0.73 vs 6.68 ± 0.80; patients vs volunteers; p <0.05). The SNR of ATP of akinetic regions may predict recovery of function after revascularization in patients with myocardial infarction.