We obtained sixty normal chest postero-anterior(PA) radiographs with high kilovoltage technique(90-110kVp), 10 radiographs from the consecutive normal persons in each decade from twenties to seventies to analyze normal course and appearance of
azygoesophageal recess (AER) line. (AER) line. CT scans from sixty consecutive normal persons were correlated with the radiographs to see how the line is formed and what structure the line abuts. In 20 patients with a lesion in AER area(10 with
subcarinal lymphadenopathy of various size, five with left atrial enlargement, three with lesions in the esophagus, and two with dilated azygos vein), radiographic and CT correlation was done with main attention to the pattern of displacement of
the
azygoesophageal line.
In normal chest PA radiographs, AER was shown as a straight line in young adults. As age increased, it was seen as a smooth are with convexity to the left. Sigmoid shape with midline cross was noted in an aged person. At the level of the right
main
bronchus on CT, AER was noted along the right lateral aspect to the vertebral margin in young adults. It extended medially as age increased. Caudally the recess extended more medially. The azygos vein usually bordered the recess. The esophagus or
mediastinal fat sometimes bordered the recess in caudal level. In normal persons, the recess appeared deeper on plain radiographs than on CT. On plain radiographs, there were no changes in contour of AER with subcarinal lymphadenopathy of less
than
2.5cm in diameter. However right sided and downward displacement of AER line just below the carina was noted with lymphadenopathy of more than 2.5cm in diameter. With left atrial enlargement, obliteration of the line was noted at T8-10 level.
Focal
right sided bulging of the line was noted with esophageal cancer Dilatation of azygos vein caused the line to appear with right sided displacement.
In conclusion, AER line can be delineated with various features on radiographs with high KVP technique, depending on the age of normal persons and the formation of the line can be explained with CT. Displacement and change in the contour of the
line can
be seen with various mediastinal diseases.
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