Journal of Ultrasound in Medicine, Vol 10, Issue 8 423-426, Copyright © 1991 by American Institute of Ultrasound in Medicine
In utero sonographic appearance of the atrial septum primum and septum secundum
P. Kachalia, J. D. Bowie, D. B. Adams and B. A. Carroll
Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710.
We present our observation of the sonographic appearance of the septum
primum and septum secundum. The septum primum, as the valve of the foramen
ovale, has been previously described as a mobile, echogenic line or dot in
the left atrium. We believe that these previous descriptions recognize only
a small part of a more complex three-dimensional shape. We studied 14 ideal
patients, none of whom were referred for suspected fetal cardiac disease.
In 1 case the septum primum was seen as a flaplike structure and in 8 cases
as a circular structure. In 5 cases it was seen as both flaplike and
circular, depending on the scan plane selected. A three-dimensional
description of the shape of the septum primum, based on the work of Crelin,
is proposed, which explains these two appearances. A better understanding
of this anatomical feature may prevent mistaking the septum primum for an
abnormality and provide the basis for future advances in fetal
echocardiography.
