Fetal lung immaturity was diagnosed by the analysis of amniotic fluid, while to avoid invasive nature of amniocentesis, ultrasound
B-mode imaging gray level histogram width is applied to detect fetal lung immaturity, of which advantage is its non-invasive nature,
accordingly, repeated application is able using ultrasound techniques.
Keywords: Fetus; Neonatal Respiratory Distress; Amniotic Fluid; Ultrasound B-Mode; Steroid Therapy of Fetal Lung Immaturity;
Repeated Tests of Maturity
It is the measurement of gray level of every pixel of ultrasound
B-mode images, where all pixel intensity is shown by the histogram
of B-mode image, [1] of which origin is pixel gray level intensity
of 1x1cm area of images (region of interest, ROI), of which
representative function is selected by the ultrasound B-mode user.
Fetal lung image
Fetal lung image is visualized beside fetal heart on the ultrasound
B-mode of pregnant woman. [2] One by one cm region of interest
(ROI) [3] is placed on fetal lung and press “histogram” button, then
fetal lung pixel histogram is illustrated as Figure 1, where the length
A divided by B (%) is GLHW Figure 1. Automatic GLHW is “%W” in
the histogram of Aloka B-mode ultrasound devices.
Fetal lung GLHW calculation, standardization, and fetal
lung maturity
Fetal lung GLHW was low in young fetus, while fetal liver GLHW
was almost constant, thus fetal lung GLHW was standardized when
it is divided by fetal liver GLHW [4,5]. where fetal lung immaturity
was decided when the ratio of fetal lung and liver GLHW multiplied
by gestational weeks was less than 29, while fetal lung is mature if
fetal lung and liver GLHW ratio multiplied by gestational weeks was
29 or more. Fetal lung/liver GLHW ratio multiplied by gestational
weeks’ sensitivity to predict neonatal Respiratory Distress
Syndrome (RDS) was as high as 96% and sensitivity was 72% in
ROC curve analysis [4,5], namely, the sensitivity to predict neonatal
RDS was 96% and specificity was 72% [5]. Since immature fetal
lung causes neonatal Respiratory Distress Syndrome (RDS), it is
important that the sensitivity of the GLHW to predict neonatal RDS
was 96% and specificity 72%, which were the highest in various
indices including amniotic fluid tests to predict fetal lung immaturity
and neonatal RDS, namely, it was the goal to detect immature fetal
lung and predict neonatal RDS, suggesting neonatal lung treatment
with artificial surfactant after birth. The 96% high sensitivity and
72% specificity in ROC curve are important information to neonatal
treatment since immature fetal lung causes neonatal Respiratory
Distress Syndrome (RDS), as the sensitivity and specificity of
GLHW to predict neonatal RDS was 96% and specificity was 72%,
which were the highest among various indices to predict fetal lung
immaturity and neonatal RDS, namely, fetal lung immaturity study
arrived at the goal to detect almost all immature lung and neonatal
RDS using GLHW.
Figure 1: Calculation of GLHW on the histogram of fetal
lung in the study of fetal lung immaturity.
As the technique to detect fetal lung immaturity was totally noninvasive,
GLHW can be studied repeatedly in preterm pregnancy,
and also estimate the effect of steroid to promote fetal lung maturity
repeatedly. It will be possible to discuss whether artificial surfactant
would be repeated or not with the results of GLHW analysis of fetal lung. The GLHW tissue characterization enabled the diagnoses of
gynecologic tumor malignancy, fetal brain periventricular echo
density, meconium stained amniotic fluid predicting fetal asphyxia
and amniotic aspiration syndrome, and possible diagnosis of
adult liver diseases [3,5]. General application of ultrasonic tissue
characterization is possible using the histogram of common
ultrasound B-mode imaging devices in GLHW technique. Noninvasive
nature of GLHW tissue characterization in the diagnosis of
fetal lung immaturity will further promote the perinatal medicine.
Further application of GLHW in tissue characterization will promote
various pathologic diagnosis including adult studies in the future.