Purpose: This study was performed to determine the normal thickness of fat in the interatrial septum as demonstrated by CT.
Method: Eighty-seven subjects underwent helical chest CT examination as part of a separate protocol to compare the quantification of coronary artery calcification by CT to coronary angiographic findings, using a slice width of 3 mm, reconstructed every 1.5 mm. The thickness of the interatrial fat in both groups was measured anterior and posterior to the fossa ovalis. The mean and standard deviation were calculated.
Results: The mean thickness of interatrial fat anterior and posterior to the fossa ovalis was 4.6 (SD = 2.5) and 3.7 (SD = 3.1) mm, respectively.
Conclusion: The normal range of thickness of the interatrial fat is 0-9.6 mm anterior to and 0-9.9 mm posterior to the fossa (2 SD above the mean).