Moderated Poster Presentation II Saturday, January 22, 2005 311. MRI of Acute Myocardial Infarction: Evaluation of Functional Recovery

Introduction: Myocardial viability assessment is crucial in prognostic stratification and therapeutic decision making for patients after acute myocardial infarction. MRI has shown high capability in viability assessment, also compared to current clinical tools. Purpose: To define contrast enhanced (CE) MRI role in functional recovery prediction after acute myocardial infarction. Methods: 43 consecutive patients with first AMI (64 ± 9 yrs., 36 anterior, 7 inferior, 37 primary PTCA, 6 thrombolysis) underwent cineand CE-MRI (GE Signa Horizon Echospeed; GE Signa LX Excite) within fifth day after onset. Cine-MRI was performed in short axis (6–8 slices, Fastcard and FIESTA sequences); first pass imaging (IR-prep FGRE and FGRE-ET with iv 0.1 mmol/kg Gd-DTPA, 3 mL/s) was obtained on three short axis slices (basal, mid-ventricular and apical); multi-slice short axis (6 slices) delayed T1 imaging (IR-prep FGRE) was obtained 20 min after Gd injection. A total amount of 731 segments were classified as: 1) normal first-pass, absent or delayed hyperenhancement; 2) hypoenhancement at first-pass, delayed hyperenhancement; 3) hypoenhancement both at first-pass and delayed imaging. Segments out of first-pass slices (total amount 774) were classified at delayed imaging as normal (= type 1), hyperenhanced (= type 2) and hypoenhanced (= type 3). Patterns 2 and 3 were considered non viable. At six months MRI assessed functional recovery. Results: Pattern 1 was observed in 1262 segments, with functional recovery appreciated in 1195 (94.7%). Pattern 3 was present in only 31 segments, without recovery (100%). Pattern 2 was observed in 212 segments: out of them, 39 showed recovery (18%). Conclusions: Patterns 1 and 3 respectively identify viable and non viable tissue. Pattern 2 is less specific early after AMI, as it may represent also viable myocardium and should be carefully interpreted.