Abstract
BackgroundAccurate evaluation of infarct size by cardiac magnetic resonance (CMR) has important clinical significance. We examined how well a qualitative visual method of scoring (VS) the extent of myocardial infarction correlates with a quantitative planimetry (PL) method of determining the extent of left ventricular (LV) infarct size.Methods51 consecutive patients with evidence of myocardial infarction by CMR were evaluated. Two different methods were used to calculate infarct mass as percentage of LV mass. A quantitative method, planimetry, was performed using an NIH software algorithm in which infarct mass was calculated based on a manual drawing of infarcted regions. In a second approach, a qualitative visualization scoring of infarcted regions was performed based on a segmental model in which each short axis slice was evenly divided into 12 segments. Transmural extent of hyperenhancement (HE) was then graded on a 4-point scale: 0, 0% HE; 1, 1-25% HE; 2, 26-50% HE; 3, 51-75% HE; 4, 76-100% HE. The final score of each patient (sum of areas of HE) was divided by the total possible score, yielding the infarct size as a percentage of LV mass.ResultsThe mean LV ejection fraction was 34±16%; the mean infarct size as a percentage of LV mass was 20±12 by planimetry, and 25±12 by VS (p: NS). The correlation coefficient between the two different modalities was 0.84.ConclusionThis study showed a good correlation between a qualitative and quantitative method of determining infarct size.