Quantitative Assessment of Atrial Regional Function Using Motion Estimation Computed Tomography

OBJECTIVES We validated a novel image-based motion estimation computed tomographic (CT) technique (iME) to quantify atrial regional function in swine in vivo. MATERIALS AND METHODS Domestic swine (n = 8) underwent CT scan with intravenous contrast before and after median sternotomy where 15 to 30 glass beads were sutured to the atria to calculate the motion estimation error. Four-dimensional motion vector field was estimated using iME. Area change ratio (%AC) was calculated over the atrial endocardium to assess the surface deformation. RESULTS The error between the measured and the calculated coordinates based on motion vector field was 0.76 ± 0.43 mm. The %AC was regionally heterogeneous. The %AC time course was significantly different between the right and the left atriums (P < 0.001) as well as between the right atrial appendage and the right atrial chamber (P = 0.004). CONCLUSIONS Quantitative assessment of atrial regional function using iME is highly accurate. Image-based motion estimation computed tomographic (CT) technique can quantify subtle regional dysfunction that is not apparent in global functional indices such as ejection fraction.