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The quantitative lung index: the left lung
Eftichia V Kontopoulos1, Luis F Quintero2, Ramen Chmait1,3
1The USFetus Research Consortium, Miami, FL, USA.
Objective:
We have previously described a gestational age-independent sonographic parameter to assess fetal lung growth in the right lung (right quantitative lung index, or QLI-R). The purpose of this study was to develop a similar sonographic parameter to assess the growth of the left lung in the fetus, independent of gestational age, or QLI-L.
Study Design:
A new index, the QLI-L was derived using published formulas for the head circumference (HC) and the area of the base of the left lung (LA), with the corresponding percentiles.
Results:
Left lung growth can be expressed using the following formula: The 50th percentile of the QLI-L remained approximately constant at 1.0 for the GA between 16-32 weeks. A small left lung (<1st percentile) was defined as a QLI-L < 0.5.
Conclusions:
Fetal left lung growth can be adequately described independent of gestational age using the QLI-L. Further experience is needed to assess the clinical accuracy of the QLI-L in characterizing fetal left lung growth.
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