Centro Médico Profesional Rosancar. Barquisimeto, Estado Lara, Venezuela.
The fetal upper mediastinum can be evaluated using a four level approach. Each level has a well define landmarks that can be recognized easily.
1) Level I or lower level
This is the lower level of the fetal upper mediastinum, and can be recognized by identifying the division of the main pulmonary artery into the right and left branch.
This level is useful to identify cases of pulmonary stenosis or absent pulmonary valve.
Images 1,2: Level 1 of the fetal upper mediastinum, main pulmonary artery (MPA), left pulmonary artery (LPA), right pulmonary artery (RPA), ascending aorta (Ao) and superior vena cava (SVC).