Arquivos Brasileiros de Cardiologia - Volume 83, Nº 2, Agosto 2004 118 Cardiac magnetic resonance imaging has undergone great de- velopment in the last decade, and its applications for assessing patients with cardiac ischemic disease are increasingly compre- hensive. Current cardiac magnetic resonance imaging techniques, especially the protocols based on delayed contrast enhancement, provide precise delimitation of the areas of myocardial necrosis or fibrosis in patients with previous infarction 1-7 . On delayed contrast- enhanced images, the infarcted areas had a very increased signal intensity (white areas) as compared with those of healthy myo- cardium (dark areas). The marked contrast between the necrotic or fibrotic tissue and the intact myocardium (signal intensity may be up to 10 times greater in infarcted areas) 8 , in addition to the excellent spatial resolution provided by cardiac magnetic resonance imaging, allow a precise evaluation of the infarcted area. In a study published in 1998, Wu et al 9 reported that infarction size, expressed as a percentage of left ventricular mass, has a significant prognostic value in patients with acute myocardial in- farction. In addition, 2 other recent studies 10,11 showed that in- farcted mass evaluation was predictive of the recovery of overall and segmentary systolic function in that group of patients. Fur- thermore, a recent study by Kim et al 12 reported that the presence of myocardial viability, defined as the regional functional recovery after myocardial revascularization, may be determined through quantification of the transmural extent of the infarction. That same study also reported that the greater the dysfunctional myocardial mass that was viable prior to the intervention, the greater the overall recovery of the ejection fraction after revascularization. Therefore, determination of the infarcted mass on cardiac magnetic resonance imaging may provide important and very useful infor- mation for the management of patients with previous acute myo- cardial infarction. Currently, cardiac magnetic resonance imaging is considered the best method for assessing left ventricular infarcted mass, sur- passing the PET technique for detecting subendocardial defects 13 . The technique usually used is direct quantification through planimetry of the delayed contrast-enhanced areas. However, planimetry is a very laborious method that requires a considerable amount of time after image processing. In addition, it requires the use of specific software, which is not always easily available. On the other hand, the scoring method, which is based on the semiquantitative visual assessment of delayed contrast-enhanced images, is a much faster and more practical alternative for determining infarction extension. Original Article Quantification of Left Ventricular Infarcted Mass on Cardiac Magnetic Resonance Imaging. Comparison Between Planimetry and the Semiquantitative Visual Scoring Method Clerio Francisco de Azevedo Filho, Marcelo Hadlich, João Luiz Fernandes Petriz, Luís Antonio Mendonça, Jorge Neval Moll Filho, Carlos Eduardo Rochitte Rio de Janeiro, RJ and São Paulo, SP - Brazil Objective To compare a new semiquantitative visual scoring method with quantitative digital planimetry for determining left ventri- cular infarcted mass by use of cardiac delayed contrast-enhanced magnetic resonance imaging. Method Seventy-seven patients with previous myocardial infarction underwent delayed contrast-enhanced magnetic resonance ima- ging using a 1.5T device for assessing myocardial viability and calculating the infarcted mass. Cine magnetic resonance imaging was used for assessing left ventricular function with the Simpson method. The infarcted mass was calculated on the delayed con- trast-enhanced images according to the following 2 methods: planimetry and the scoring method. Simple linear regression and correlation and agreement between the methods and ob- servers according to the Bland-Altman plot were used. Results The infarcted areas in all 77 patients were detected by use of cardiac delayed contrast-enhanced magnetic resonance ima- ging. The size of the infarction measured by planimetry was similar to that obtained with the scoring method, with a mean difference between measurements of only 1.03% of the left ventricular mass. Inter- (0.41%) and intraobserver (0.34%) va- riabilities indicated an excellent reproducibility of the scoring method. Infarcted mass showed a good correlation with ejection fraction and indexed end-diastolic and end-systolic volumes, r=-0.76, r=0.63, and r=0.67, respectively. Conclusion In patients with previous myocardial infarction, delayed- enhanced magnetic resonance imaging provides accurate infarct size quantification by planimetry and by semiquantitative score. Key words myocardial infarction, magnetic resonance imaging, myocardial viability Rede de Hospitais D’Or, LABS/RJ, and InCor of the Hospital das Clínicas of the FMUSP Mailing address: Carlos Eduardo Rochitte - Av. Dr. Eneas de Carvalho Aguiar, 44 - Cep 05403-000 - São Paulo, SP, Brazil E-mail: rochitte@incor.usp.br Received: 4/17/03 Accepted: 12/3/03 English version by Stela Maris Costalonga