Four Dimensional Fetal Echocardiography [video]

The examination of the fetal heart is part of the comprehensive fetal scan, but this examination is still considered a challenge even for experienced sonographers. Over the years, the number of ultrasound techniques used in fetal cardiology impressively increased and no other fetal organ is examined with as many modalities as the fetal heart including high resolution two dimensional (2D) imaging, M-mode examination, spectral, color, power, high-definition digital Doppler, B flow as well as tissue Doppler. It is, however, common knowledge that despite the availability of all these technologies, screening programs, especially when limited to the study of the “four chamber view”, have shown disappointing low detection rates for congenital heart disease (CHD). Although the identification of CHD can be improved by routinely visualizing the outflow tracts, their diagnosis is greatly affected by the skill of the operator as well as his ability to interpret the findings. Very recently, three- and four- dimensional (3D and 4D) technologies have been introduced in fetal cardiology and have revolutionized the way in which it is possible to study the heart. 4D ultrasonography may reduce the operator dependency of CHD diagnosis and adds the possibility to obtain offline virtual planes in cardiac examinations, views of the fetal heart difficult or impossible to obtain with conventional 2D ultrasound. This new fetal cardiology ebook, we believe, will be of great value for all practicing clinicians wanting to start the study of the fetal heart with 4D ultrasonography. We have chosen a panel of contributors that are both leaders in this field and can represent the differences in practice between Europe and United States. This is a comprehensive guide intended for anyone interested in fetal heart scanning performing both routine screening ultrasonographic examinations and targeted heart scans. It aims to assist the reader with the following questions: how can I use this technology to acquire cardiac volumes?; how do I handle cardiac volume data sets after acquisition?; how can I improve diagnosis and definition of CHD? It is our hope that this book will provide a bridge between scientists using and testing new technologies for research purposes and clinicians wishing to improve their daily practice

Uterine artery Doppler velocity waveforms in twin pregnancies

Objective: To compare uterine artery resistance index values in twin and singleton pregnancies, to examine eventual modifications of these values in twin pregnancies complicated by gestational hypertension and preeclampsia, and to determine whether resistance index values in twin pregnancies could predict the development of gestational hypertension and preeclampsia. Methods: In a cross-sectional study, reference limits for gestation were constructed for the uterine artery resistance index (higher, lower, and mean values) in 96 uncomplicated twin pregnancies and compared to the reference limits constructed from 315 normal singleton pregnancies. Uterine artery resistance indexes obtained in 53 twin pregnancies complicated by either gestational hypertension or preeclampsia were compared with the newly established nomograms. The clinical efficacy of the uterine artery resistance index to predict hypertensive complications was evaluated prospectively in 64 twin pregnancies studied at 20-24 weeks' gestation. Results: In both singleton and twin pregnancies, uterine artery resistance indexes decreased linearly with advancing gestation. However, twin pregnancies showed significantly different slopes and constant values, resulting in lower resistance indexes at all gestational ages examined. No significant differences were found when comparing resistance indexes in all patients with gestational hypertension or preeclampsia to the reference limits. Statistically significant differences were obtained for the higher (P less-than-or-equal-to .05) and mean (P less-tha-or-equal-to .01) resistance indexes when the comparison was restricted to preeclamptic patients. In the twin pregnancies studied at 20-24 weeks' gestation, the diagnostic efficacy of the uterine artery resistance index for predicting the development of gestational hypertension and/or preeclampsia was disappointingly low (k < 0.10). Conclusions: Resistance index values in the uterine artery are lower in twin pregnancies than in singleton pregnancies. Gestational hypertension and preeclampsia may occur in twin pregnancies despite normal uterine artery velocity waveforms, suggesting a limited role of this measurement in the management and prediction of hypertensive complications in twin pregnancies