Myocardial fibrosis assessment by semiquantitative, point-counting and computer-based methods in patients with heart muscle disease: a comparative study

Aims: No study has directly compared different histomorphometric methods of quantification of myocardial fibrosis. Therefore we compared the results o f semiquantitative, point-counting and computer-based methods in the assess ement of myocardial fibrosis in a consecutive series of endomyocardial biop sy samples from patients with heart muscle disease. Methods and results: Histological samples (at least three per patient) were obtained by endomyocardial biopsy from II patients with focal myocarditis and from 24 ambulatory patients with idiopathic dilated cardiomyopathy, or during surgery in 10 patients who underwent partial left ventriculectomy, S amples were cut and stained with Masson-trichrome tor better contrast. From each sample, a representative field was digitized, and the amount of fibro sis was assessed by semiquantitative scoring, by point-counting, and by com puter-based software. Semiquantitative scoring correlated with both point-c ounting (Spearman's r = 0.69, P < 0.0001) and computer-based (Spearman's r = 0.83, P < 0.0001) methods. There was also a good correlation between poin t-counting and computer-based methods (r = 0.71, P < 0.0001). However, when compared with the point-counting method, the computer-based method overest imated percent fibrosis by 3.0 +/- 6.7% (P = 0.004). This overestimation co rrelated with the mean percent fibrosis (r = 0.38, P = 0.014). Conclusions: Our data show good correlations between the three methods of m yocardial fibrosis assessment. However, systematic differences between them emphasize that this should be taken into consideration when comparing resu lts of the studies using different methods of fibrosis assessment.