Both methodologies show limitations related to the infarct size SAR131675 1433953-83-3 estimation accuracy using parameters that are affected and distorted by cardiac remodeling subsequent to MI. Moreover, a random dispersion of results around the predicted bias was observed, demonstrating that MIQuant results are reliable independently of the size of infarction. The repeatability and reproducibility of MIQuant results were also confirmed by the use of three independent measures obtained by four independent observers. Overall these results indicate that MIQuant is a reliable alternative to the manual quantification of infarct size. Despite being a determinant factor for an accurate estimation of the infarct size, the number of transverse sections used for such analysis is extremely variable across studies. One of the advantages of MIQuant over the classical manual quantification is the 4.5 fold reduction on the time spent on the analysis, thus improving time-efficiency and allowing the investigator to increase the number of sections per analysis and consequently the accuracy of results. MIQuant is available as freeware for research use. The widespread use of MIQuant will constitute by itself a major improvement towards normalization of infarct size assessment by restricting the methods to the area and midline length, by standardizing the histological stain used and by restricting the criteria for the identification of the infarcted region. Our results also indicated a tendency, although not statistically significant, for reduced inter-observer variability in MIQuant infarct size scores when compared to manual analysis. This may well be underestimated given that the observers in this study were investigators that received similar training on infarct size calculation. It is therefore expected that the diversity of criteria on infarct identification/calculation of observers with different backgrounds will result in increased variability for the manual outcome. In contrast, we demonstrated that MIQuant efficacy is independent of previous training with the software and experience on MI size calculation. An interesting experiment would be a comparative analysis between MIQuant and manual quantification with experts from different laboratories to therefore undoubtedly clarify whether MIQuant contributes to the homogenization of infarct size results. Our attempts to engage in this task experts with previous published work on infarct size histological quantification, met with little success and the intent was therefore aborted. For the interpretation of this study several limitations should be considered: firstly a single species was used for the validation of MIQuant, and secondly the only model of cardiac induced-ischemia performed was the permanent LAD coronary artery ligation. However, the pathophysiological and morphological alterations following MI are similar in the rat and the mouse, supporting the applicability of MIQuant for the quantification of rat infarcts. The extension of MIQuant to other infarction models, e.g. ischemia-reperfusion or the cryoinjury, is of major interest. Hence, because the software recognizes the infarction region by the collagen deposition.