Automatic quantification of cardiac muscle properties in tissue sections might provide important information related to different types of diseases. Second harmonic generation (SHG) imaging provides a stain-free microscopy approach to image cardiac fibers that, combined with our methodology of the automated measurement of the ultrastructure of muscle fibers, computes a reliable set of quantitative image features (sarcomere length, A-band length, thick–thin interaction length, and fiber orientation). We evaluated the performance of our methodology in computer-generated muscle fibers modeling some artifacts that are present during the image acquisition. Then, we also evaluated it by comparing it to manual measurements in SHG images from cardiac tissue of fetal and adult rabbits. The results showed a good performance of our methodology at high signal-to-noise ratio of 20 dB. We conclude that our automated measurements enable reliable characterization of cardiac fiber tissues to systematically study cardiac tissue in a wide range of conditions.

The authors acknowledge the cvRemod project under the CENIT 20092012 program of the Industrial and Technological Development Center (CDTI). This study was partially supported by grants from Instituto de Salud Carlos III and Ministerio de Economia y Competitividad (Ref. PI11/00051, PI11/01709, PI12/00801, and SAF2012-37196), Fondo Europeo de Desarrollo Regional de la Unión Europea “Una manera de hacer Europa,” Spain; Obra Social ‘La Caixa,’ Spain; the Fundación Mutua Madrileña; Fundació Agrupació Mutua; Cerebra Foundation for the Brain Injured Child (Carmarthen, Wales, UK); and the Seventh Framework Programme (FP7/2007-2013) under Grant No. 611823. P.G.C. was supported by the Programa de Ayudas Predoctorales de Formación en investigación en Salud (FI12/00362) from the Instituto Carlos III, and A.G.T. was supported by IDIBAPS Predoctoral Programme.