The lecture is devoted to the morphological characteristics of the maturation of lung tissue structures in the fetal period. Fetal histology of the lungs presents the intrauterine development of lung tissue in four successive stages: pseudoglandular, canalicular, saccular and alveolar, each has specific morphological criteria. The following morphological features are predetermined: the development of alveolar epithelium, the ratio of mesenchyme towards the area in alveolar spaces, the degree of proliferation and location of vessels of the microcirculatory bed towards prealveolar partitions. During the fetal period the alveolar columnar epithelium is flattened and differentiates into alveolocytes type I and II, the area of the mesenchyme gradually decreases and by the birth of a full-term newborn kid it is present mainly in the thickness between the alveolar septa, microcirculation vessels, initially laying deep in the thickness of the mesenchymal tissue, gradually proliferate, approach the pre-alveolar epithelium, channeling it with the formation of alveolar capillary membranes. Air exchange in the lung tissue is mainly provided with two factors: the presence of second-order alveolocytes capable of producing surfactant, and a sufficient formation of alveoli as well. This work summarizes the basics of fetal lung histology with the demonstration of histological preparations of the lungs at different stages of intrauterine development.
Лекция посвящена морфологической характеристике созревания структур ткани легких в фетальном периоде. Внутриутробное развитие легких плода подразделяют на четыре последовательные стадии: псевдожелезистую, каналикулярную, саккулярную, альвеолярную. Каждая из них обладает специфическими морфологическими критериями. Определяющими для дифференцировки стадий являются следующие морфологические особенности: развитие преальвеолярного эпителия, соотношение мезенхимы и площади преальвеолярных пространств, степень пролиферации и расположение сосудов микроциркуляторного русла относительно преальвеолярных перегородок. В течение фетального периода преальвеолярный столбчатый эпителий уплощается и дифференцируется на альвеолоциты I и II порядка, площадь мезенхимы постепенно уменьшается и к моменту своевременных родов доношенного новорожденного присутствует в основном в толще межальвеолярных перегородок, сосуды микроциркуляторного русла, изначально распространенные глубоко в толще мезенхимальной ткани, постепенно пролиферируют, приближаются к преальвеолярному эпителию, «канализируя» его с образованием альвеолокапиллярных мембран. Воздухообмен в легких главным образом обусловлен двумя факторами: наличием альвеолоцитов II порядка, способных продуцировать сурфактант, и достаточным количеством сформированных альвеолокапиллярных мембран. Данная работа обобщает основы фетальной гистологии легких с демонстрацией гистологических препаратов легких на разных этапах внутриутробного развития.

UNASSIGNED: Ebstein anomaly (EA) is a cardiac malformation with highly variable presentation and severity with limited perinatal management options. We present incorporation of fetal lung measurements into a multidisciplinary evaluation for counseling and predicting postnatal outcomes in patients with severe EA.
UNASSIGNED: Five fetuses with severe fetal EA were reviewed. Third trimester sonographic observed/expected total lung area (O/E TLA) and lung to head ratio (O/E LHR), fetal MRI total fetal lung volume ratio (O/E-TFLV), echocardiographic cardio-thoracic ratio (CT ratio), sonographic estimated fetal weight (EFW) by Hadlock formula and presence of hydrops, were used to guide perinatal management.
UNASSIGNED: Three of five had appropriate fetal growth, were delivered at term in a cardiac operative suite, and underwent immediate intervention with good neonatal outcomes. Two had severe fetal growth restriction (FGR), CT ratios > 0.8 and O/E LHR and TLA < 25%. One of which delivered prematurely with neonatal demise and one suffered in utero demise at 34 weeks.
UNASSIGNED: FGR, hydrops, increased CT ratio and reduced O/E LHR and TFLV are potential prognosticators of poor outcomes in severe EA, and should be validated in larger cohorts that would allow for a statistical analysis of the predictive utility of these measurements.
Pulmonary hypoplasia is associated with severe morbidityThere are limited prognosticating tools to risk stratify and guide management in cases of severe prenatal Ebstein anomaliesFetal MRI may improve prognostication for fetuses with EA.

OBJECTIVE: To report the longitudinal lung growth and prognosis of fetuses with severe left sided congenital diaphragmatic hernia (CDH) treated with fetoscopic tracheal occlusion (FETO) in a single institution.
METHODS: Fetal lung size (observed-to-expected lung area to head circumference [o/e-LHR]) was measured in seven consecutive fetuses with isolated severe left-sided CDH who underwent FETO. Fetal lung growth was used to prognosticate survival and need for ECMO.
RESULTS: Seven consecutive fetuses had a FETO procedure in the timeframe of this study. A total of 44 longitudinal ultrasound were performed to evaluate lung development. FETO was performed at GA 28.5 ± 0.5 weeks. Five (71.4%) infants survived to one-year follow-up and ECMO was needed in three patients (42.8%). Fetal lung response was observed in all fetuses; mean o/e-LHR increased from 22.5% ± 1.4 before FETO to 44.4% ± 9.8 before delivery. Infants who survived had a higher percentage of fetal lung growth (21.8%) than those who died (8.25%).
CONCLUSIONS: Our study supports the hypothesis that FETO promotes fetal lung growth in fetuses with severe left-sided CDH, and the fetal pulmonary response seems to be associated with improved outcomes after the procedure.

OBJECTIVE: The aim of this study was to investigate the reproducibility of a standardized method to assess the ultrasound liver-to-thoracic area ratio in fetuses with congenital diaphragmatic hernia.
METHODS: We selected 24 images of 9 fetuses diagnosed with left-sided at our institution between January 2010 and December 2017. Eight operators (1 maternal-fetal medicine specialist and 7 sonographers) reviewed the selected images and assessed the ultrasound liver-to-thoracic area ratio according to a standardized protocol. We evaluated the correlation between operators using the intraclass correlation coefficient and compared agreement between the sonographers and a physician with experience in measuring the ultrasound liver-to-thoracic area ratio using a Bland-Altman analysis.
RESULTS: Good intraoperator reproducibility was observed for the standardized ultrasound liver-to-thoracic area ratio (intraclass correlation coefficient, 0.78). Good agreement among sonographers and the physician was also observed for the standardized measurements (bias, 0.01; precision, 0.03; limits of agreement, -0.05 to + 0.07).
CONCLUSIONS: We demonstrated that good intraoperator and interoperator reproducibility of ultrasound liver-to-thoracic area ratio assessment is feasible after standardizing the method in our center.

OBJECTIVE: This study investigated the reproducibility of standardization of lung-to-head ratio measurements in congenital diaphragmatic hernia (CDH) at our center among sonographers after we standardized the method.
METHODS: We reviewed ultrasound images of 12 fetuses with CDH at Mayo Clinic from 2010 to 2016. Nine operators (1 maternal-fetal medicine specialist with experience in measuring the lung-to-head ratio and 8 sonographers), who were blinded to previous findings, reviewed 33 selected images from 12 fetuses with left CDH. The method for lung-to-head ratio measurement was standardized before starting the measurements. The lung-to-head ratio was assessed by different methods to obtain the lung areas: anteroposterior, longest, and area tracing. We evaluated the correlation between operators using the intraclass correlation coefficient (ICC). We also compared agreement between the sonographers and a physician with experience in measuring the lung-to-head ratio using a Bland-Altman analysis.
RESULTS: The methods with the best interoperator reproducibility were the standardized anteroposterior lung-to-head ratio (ICC, 0.69) and the standardized lung-to-head ratio tracing (ICC, 0.65) compared to the longest lung-to-head ratio (ICC, 0.56). The standardized lung-to-head ratio tracing had the best agreement among sonographers and the physician (bias, 0.11; limits of agreement, -0.27 to +0.49) than the anteroposterior lung-to-head ratio (bias, 0.35; limits of agreement, -0.13 to + 0.83) and the longest lung-to-head ratio (bias, 0.27; limits of agreement, -0.35 to +0.89).
CONCLUSIONS: We demonstrated that the lung-to-head ratio tracing method has high interoperator reproducibility and the best agreement among the operators at our center. Further multicenter studies are necessary to confirm our results.