| Study background:With the rapid development of modern medicine and medical new technology constantly emerging, more and more recognition and fetal abnormalities in the womb have been found and known by people gradually, the study of fetal pulmonary hypoplasia has become one of the hot topics in the study of prenatal ultrasound diagnosis. Therefore, information of normal ultrasound measurements of fetal lung volume and evaluation and analysis with changing rules of its gestational age and fetal quality are particularly important.Objective:With the use of three-dimensional ultrasonic rotation technology (Virtual organ computer-aided analysis, VOCAL) to measure fetal lung volume, different gestational age normal reference valu rages are set up, fetal lung development is evaluated, rules of normal fetal lung volume changing with gestational age and fetal quality are analyzed and discussed. Ratio of lung volume and fetal quality is used to evaluate fetal pulmonary hypoplasia, with which the clinical value to prenatal diagnosis of fetal pulmonary hypoplasia are analyzed and explored.Study object and methods:Single pregnancy of270cases of normal fetus and20cases of high-risk pulmonary hypoplasia (PH) fetus are used as study object, the gestational age is17～36weeks, with the application of three-dimensional ultrasound rotation technology, the fetal lung volume of the left lung and the right one are manually measured, and by adding together both of that, the total lung capacity (the TLV) is obtained. Abdominal2d ultrasound measurement is used to evaluate relative biological indicators of fetal growth and development, including femur length (FL), humerus length (HL), abdomen circumference (AC), biparietal diameter (BPD), and head circumference (HC). Hadlock equation system is used to calculate and generate the fetus quality automatically; ratio of lung volume and fetal quality is calculated out, condition of fetal lung development is evaluated, fetal postpartum and autopsy results are traced and in contrast with the results of prenatal diagnosis, the accuracy and reliability of three dimensional ultrasonic VOCAL rotation technologies are evaluated.Results:Normal group of fatal left lung volume and right one and total lung capacity are significantly positively related with gestational age (r value are0.95,0,94,0.96, p value is less than0.01), average value of left lung volume varies from20weeks of4.05ml,28weeks of17.39ml to34weeks of32.16ml, average value of right lung volume varies from20weeks of5.64ml,28weeks of22.25ml to34weeks of40.24ml, average value of total lung volume varies from20weeks of9.69ml,28weeks of39.64ml to34weeks of72.40ml, and lung volume is increased with the rise of fetal quality and a trend of rising is showed (r value is0.98, p<0.01). Seen from above, the relativity of normal fetal lung volume and fetal quality is more than that of fetal lung volume and gestational age. When fetal lung hypoplasia occurs, the quality of the lung is significantly reduced, fetal lung volume is significantly decreased, and the ratio of lung volume and fetal quality is significantly lower than that of normal control group. In20cases of fetus with high-risk of pulmonary hypoplasia,2cases with oligohydramnios failes to get a satisfactory3d ultrasound images, the success rate to get lung volume is90%using three-dimensional ultrasonic VOCAL rotation technology in high-risk of pulmonary hypoplasia fetuses, the accuracy in diagnosis of fetal PH was88.88%in application of the ratio of lung volume and fetal quality, positive predictive value is91.66%, negative predictive value is83.33%, sensitivity is91.66%, and specificity is83.33%.Furthermore, with3d rotation technology, paired t test is made between the measured lung volume and the actual lung volume that got after autopsy in application water volume displacement method, t=0.90, p=0.929>0.05, which shows that these two kinds of measurement method is consistency. Using linear regression analysis the correlation of two measuring methods, r=0.993, p<0.01. Paired t test is made on the ratio of lung volume and fetal quality and that of wet lung quality and fetal quality, t=1.191, p=0.25>0.05, Correlation analysis is made on the ratio of lung volume and fetal quality and that of wet lung quality and fetal quality, the correlation coefficient is0.979, p<0.01.Conclusion:(1) Normal fetal left and right lung volume and total lung volume increasing with the rising of gestational age and fetal quality, fetal lung volume and curve is positively correlated to the gestational age;(2) Fetal lung volume increases with the rise of fetal quality, there is a dominant linear relationship between them;(3) Pulmonary hypoplasia can be accurately diagnosed by the ratio of lung volume and fetal quality;(4) Three-dimensional ultrasonic VOCAL rotation technology has good feasibility and reliability to measure fetal lung volume.10figures,3tables,66references... |
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