[Initial results of a new method of sonographic diagnosis of lung maturity]

The immaturity of the foetal lung is one of the central problems in obstetrics. In this paper first results are presented to determine the maturity of the foetal lung by sonography. Using the foetal liver as a reference organ we are avoiding the known pitfalls which made it impossible in the past to standardise the foetal lung changes depending upon the age of gestation. We examined 121 patients between week 27 and week 41. In one ultrasound section cut we depicted lung and liver as well. According to the known A-mode we registered frequencies in both organs. The registered frequencies were entered digitally into a computer and checked for f mean, f max and f min. Subsequently we calculated quotients of frequencies of the foetal lung and liver. For all weeks of gestation the mean value and standard deviation were calculated. We found that the liver is an adequate reference organ, since there is no change in the reflection pattern between the different weeks of gestation. We registered significant differences in the quotients of lung and liver between the different weeks of gestation, a cutting line being week 35. A quotient of Q mean lower than 1.1 hints to lung maturity while values over 1.1 point to immaturity.