Three Dimensional Visualization of Human Cardiac Conduction Tissue in Whole Heart Specimens by High-Resolution Phase-Contrast CT Imaging Using Synchrotron Radiation

The feasibility of synchrotron radiation-based phase-contrast computed tomography (PCCT) for visualization of the atrioventricular (AV) conduction axis in human whole heart specimens was tested using four post-mortem structurally normal newborn hearts obtained at autopsy. In PCCT images of all four of hearts, the AV conduction axis was distinguished as a low-density structure, which was serially traceable from the compact node to the penetrating bundle within the central fibrous body, and to the branching bundle into the left and right bundle branches. This was verified by histological serial sectioning examination. This is the first demonstration that visualization of the AV conduction axis within human whole heart specimens is feasible with PCCT. This is likely to be a powerful tool for study of the conduction system in the setting of congenital cardiac anomalies.