Variation of the size of pulmonary venous ostia during the cardiac cycle: optimal reconstruction window at ECG-gated multi-detector row CT

The aim of this study was to investigate the variation of the size of pulmonary vein ostia during cardiac cycle using ECG-gated multi-detector row CT (MDCT). Nineteen patients were included in this study. Transaxial images at the level of right inferior pulmonary vein (RIPV) were reconstructed in increments of 5%. The ostial diameter of RIPV was measured, the reconstruction windows showing maximal and minimal diameters were selected. The ostial areas of four pulmonary veins were measured at axial image sets of two selected reconstruction windows. The measurement of RIPV revealed that the maximal diameter (1.50±0.32 cm) was generally 35% and the minimal diameter (1.28±0.28 cm) was usually at 85%. The measurement of ostial areas showed that the ostia enlarged at the end of ventricular systole when compared with those at the end of ventricular diastole, by the factors of 1.44±0.55 for the right superior, 1.25±0.23 for the right inferior, 1.45±0.81 for the left superior, and 1.31±0.26 for the left inferior pulmonary vein (P<0.05). The size of the pulmonary vein ostia is variable during the cardiac cycle and the measurement of the pulmonary veins should always be in the same phase of the cardiac cycle during the follow-up of patients.