The value of three-dimensional echocardiography derived mitral valve parametric maps and the role of experience in the diagnosis of pathology

Background: Accurate segmental mitral valve (MV) analysis is essential for surgical planning. Although real-time three-dimensional (3D) transesophageal echocardiography has improved the ability to visualize the MV, accurate localization of MV pathology from 3D transesophageal echocardiographic images still remains experience dependent. Three-dimensional parametric maps of the MV obtained from these images further simplify the visualization of MV anatomy. The aims of this study were to examine whether 3D parametric maps of the MV could improve the diagnostic accuracy in localizing pathology and to determine their usefulness for readers with different levels of training. Methods: Five novice (American Society of Echocardiography [ASE] level 2), three intermediate-level (ASE level 3; <500 MV cases), and two expert (ASE level 3; >500 MV cases) readers interpreted MV segmental anatomy in 50 patients (30 with degenerative MV disease, 20 with normal MVs). All readers reviewed two-dimensional and 3D transesophageal echocardiographic and 3D parametric maps at sequential weekly sessions. The results were compared with surgical findings. Results: Expert readers were the most accurate irrespective of image type. Novice readers were the least accurate and commonly misinterpreted P2 and P3 scallops. Their accuracy was highest when interpreting 3D parametric maps (from 87% with two-dimensional transesophageal echocardiography to 92%). Intermediate readers' accuracy fell between the other two groups irrespective of image type and showed no change with the use of parametric maps. Conclusions: This is the first study to show that the interpretation of 3D parametric maps improves the accuracy of localization of MV pathology by novice readers. Therefore, parametric maps should be used routinely by less experienced readers during the assessment of degenerative MV disease.