Echogenic fetal lung masses: comparison of prenatal sonographic and postnatal CT findings.

Abstract

The aim of this retrospective study was to compare changes in size and appearance of fetal lung masses detected on prenatal sonography with those on postnatal CT. Sixteen fetuses with echogenic lung masses had undergone serial sonography in utero as well as postnatal CT scanning. Changes in size of the masses were determined by comparing initial and follow-up sonograms. The appearance of the lesions on postnatal CT scans was classified as consolidation, cavity, ground-glass opacity, or atelectasis. All sonographic and CT findings were analyzed by 2 experienced radiologists who were unaware of previous imaging results. The initial mean size of the fetal lung masses on prenatal sonography was 31 (anteroposterior dimension)x25(width)x36(craniocaudal length) mm. Follow-up serial sonography revealed complete regression of 10 masses, no change in 4, partial regression of 1, and increased size in 1. On postnatal chest CT, the mean mass size was 32x22x28 mm; 6 lesions showed no size change from that on the initial sonograms, 6 showed partial regression, and 4 showed an increase in size. Of the 10 cases with apparently complete regression on prenatal sonography, all showed positive findings on postnatal CT. The discrepancy between prenatal sonographic and postnatal CT findings supports the assumption that regression of lung masses during serial prenatal sonographic follow-up does not always indicate their complete regression.