RESUMEN
OBJECTIVE: To establish the application of three-dimensional ultrasonography in measuring fetal liver volume during the second half of normal pregnancy. DESIGN: A prospective cross-sectional study of normal fetal liver volume at 19-39 weeks of gestation (median 29 weeks). SUBJECTS: Thirty-four non-smoking women with a singleton pregnancy resulting in the delivery of a healthy infant with a birth weight between the 5th and 95th centiles according to the Kloosterman tables adjusted for maternal parity and fetal sex. METHODS: For fetal liver volume measurements, a simultaneous recording of a frontal section of the liver immediately anterior to the stomach and a sagittal section of the liver were obtained using a standard Combison 530 ultrasound machine with a 5-MHz annular array transducer for volume scanning. RESULTS: Technically acceptable fetal liver volume measurements were obtained in 25 of 34 participating women. Mean fetal liver volume data (P50) ranged between 8 ml at 20 weeks' gestation and 116 ml at 38 weeks' gestation. A statistically significant increase in normal fetal liver volume was found with advancing gestational age (p < 0.0001) and with increasing estimated fetal weight (p < 0.00001). CONCLUSIONS: Three-dimensional ultrasound allows measurement of fetal liver volume, and this demonstrated an approximately 14-fold increase during the second half of pregnancy. It is speculated that three-dimensional fetal liver volume measurement may identify the fetus at risk of growth restriction.
Asunto(s)
Procesamiento de Imagen Asistido por Computador , Hígado/diagnóstico por imagen , Ultrasonografía Prenatal , Femenino , Edad Gestacional , Humanos , Embarazo , Estudios Prospectivos , Valores de ReferenciaRESUMEN
The objective of this preliminary study was to evaluate three-dimensional ultrasonographic lung volume measurement in the normally developing fetus in the second half of pregnancy. Total fetal lung volume was determined by subtraction of fetal heart volume from thoracic volume, using the perpendicular transverse, sagittal and frontal planes of the fetus. Technically acceptable lung volume measurements were obtained in 29 out of 34 women with an uncomplicated pregnancy. A statistically significant increase in normal fetal lung volume was established with advancing gestational age and with increasing fetal estimated weight, demonstrating an approximately seven-fold rise in fetal lung volume during the second half of pregnancy. Three-dimensional ultrasonography can be applied for estimation of fetal lung volume. Whether this technique is useful in the prenatal prediction of pulmonary hypoplasia remains to be determined.
Asunto(s)
Pulmón/diagnóstico por imagen , Ultrasonografía Prenatal/métodos , Adulto , Estudios Transversales , Femenino , Madurez de los Órganos Fetales , Edad Gestacional , Humanos , Modelos Lineales , Pulmón/embriología , Embarazo , Segundo Trimestre del Embarazo , Tercer Trimestre del Embarazo , Valores de Referencia , TransductoresRESUMEN
The influence of pulsatile diameter changes on calculation of volume flow has been studied. In vitro studies and an animal study were carried out with a real-time imaging and pulsed Doppler velocity measurement system. For precise pulsatile diameter information a wall motion tracking device was incorporated. Whereas in vitro a high degree of accuracy was found for the measurements of volume flow, this could not be substantiated in the descending aorta of the fetal lamb, in which Doppler volume flow differed between -7.5 and 17% from magnetic volume flow. In a clinical study the relative influence of various diameter approximations on calculated fetal aortic volume flow was assessed in 16 normal third trimester pregnancies. Depending on the selected diameter approximation method it appeared that differences from 19% underestimation to 9% overestimation in calculated volume flow could be obtained when reference was made to volume flow derived from diameter and velocity information.
Asunto(s)
Feto/fisiología , Ultrasonografía/instrumentación , Animales , Aorta Torácica/fisiología , Velocidad del Flujo Sanguíneo , Femenino , Humanos , Embarazo , Flujo Sanguíneo Regional , Ovinos/fisiología , Factores de Tiempo , Ultrasonido/instrumentación , Resistencia VascularRESUMEN
Fetal blood flow velocity and diameter changes in the lower thoracic part of the descending aorta were compared in twenty normal pregnancies between the gestational age of 30 and 41 weeks. The mean blood flow velocity remained constant throughout the study period whereas a significant increase in vessel diameter was observed. The significant increase in aortic stroke volume and blood flow was in correlation with this diameter change.