Assessment of myocardial infarction in humans with Na-23 MR imaging: Comparison with cine MR imaging and delayed contrast enhancement

PURPOSE: To demonstrate the feasibility of sodium 23 (Na-23) magnetic reson ance (MR) imaging for assessment of subacute and chronic myocardial infarct ion and compare with cine, late enhancement, and T2-weighted imaging. MATERIALS AND METHODS: Thirty patients underwent MR imaging 8 days +/- 4 (s ubacute, n = 15) or more than 6 months (chronic, n = 15) after myocardial i nfarction by using a Na-23 surface coil with a double angulated electrocard iogram-triggered three-dimensional gradient-echo sequence at 1.5 T. In addi tion, cine, inversion-recovery gradient-echo, and, in the subacute group, T 2-weighted images (n = 9) were obtained. Myocardial infarction mass was dep icted as elevated signal intensity or wall motion abnormalities and express ed as a percentage of total left ventricular mass for all modalities. Corre lations were tested with correlation coefficients. RESULTS: All patients after subacute infarction and 12 of 15 patients with chronic infarction had an area of elevated Na-23 signal intensity that sign ificantly correlated with wall motion abnormalities (subacute; r = 0.96, P < .001, and chronic; r = 0.9, P < .001); three patients had no wall motion abnormalities or elevated Na-23 signal intensity. Only 10 patients in the s ubacute and nine in the chronic group revealed late enhancement; significan t correlation with Na-23 MR imaging occurred only in subacute group (r = 0. 68, P < .05). Myocardial edema in subacute infarction correlated (r = 0.71, P < .05) with areas of elevated Na-23 signal intensity but was extensively larger. CONCLUSION : Na-23 MR imaging demonstrates dysfunctional myocardium caused by subacute and chronic myocardial infarction.