In vivo flow dynamics of the total cavopulmonary connection from three-dimensional multislice magnetic resonance imaging

Background. The total cavopulmonary connection (TCPC) design continues to b e refined on the basis of now analysis at the connection site. These refine ments are of importance for myocardial energy conservation in the univentri cular supported circulation. In vivo magnetic resonance phase contrast imag ing provides semiquantitative now visualization information. The purpose of this study was to understand the in vivo TCPC flow characteristics obtaine d by magnetic resonance phase contrast imaging and compare the results with our previous in vitro TCPC flow experiments in an effort to further refine TCPC surgical design. Methods. Twelve patients with TCPC underwent sedated three-dimensional, mul tislice magnetic resonance phase contrast imaging. Seven patients had intra atrial lateral tunnel TCPC and 5 had extracardiac TCPC. Results. In all patients in both groups a disordered now pattern was observ ed in the inferior caval portion of the TCPC. mow at the TCPC site appeared to be determined by connection geometry, being streamlined at the superior vena cava-pulmonary junction when the superior vena cava was offset and fl ared toward the left pulmonary artery. Without caval offset, intense swirli ng and dominance of superior vena caval flow was observed. In TCPC with bil ateral superior vena cavae, the flow patterns observed included secondary v ortices, a central stagnation point, and influx of the superior vena cava f low into the inferior caval conduit. A comparative analysis of in vivo flow and our previous in vitro now data from glass model prototypes of TCPC dem onstrated significant similarities in now disturbances. Three-dimensional m agnetic resonance phase contrast imaging in multiple coronal planes enabled a comprehensive semiquantitative now analysis. The data are presented in t raditional instantaneous images and in animated format for interactive disp lay of the now dynamics. Conclusions. Flow in the inferior caval portion of the TCPC is disordered, and the TCPC geometry determines flow characteristics. (C) 2001 by The Soci ety of Thoracic Surgeons.