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        To the Editors: We appreciate your interest on our study of fetal lung volume estimation by three-dimensional ultrasonography. The question on performance of three-dimensional ultrasonography in cases of low contrast (e.g., oligohydramnios) is of significance for this technique. The technical equipment has developed fast, and imaging quality is even sufficient in cases with oligohydramnios. This allows application of this technique also in cases with low contrast. We already are using three-dimensional lung volume estimation in selected abnormal cases in prenatal diagnosis. Although many of these cases had oligohydramnios, we could easily estimate fetal lung volume in most cases. The results of this measurements have correlated with the clinical outcome. We need far more cases to give qualified answers to the question of clinical usefulness.
        We pointed out that long acquisition times limit the application of magnetic resonance imaging in prenatal diagnosis. Of course, echoplanar magnetic resonance imaging can eradicate this limitation. However, this technique is not available in our university hospital and only very few centers around our country can provide it. We think that this lack of centers equipped with echoplanar imaging, is true in many European and overseas countries. Another problem when echoplanar imaging is used in obstetrics is the lack of detailed studies of possible hazard effects of magnetic resonance imaging to the fetus. This always raises discussion regarding this issue. For example, the company that produced the magnetic resonance imaging equipment in our hospital suggests not using it during pregnancy. In contrast, three-dimensional ultrasonography is approved in obstetrics and can even reduce the exposition of the fetus to ultrasound.
        • Lee A
        • et al.
        Three dimensional ultrasound: abnormalities of the fetal face in surface and volume rendering mode.
        • Merz E
        • Bahlmann F
        • Weber G
        • Macchiella D.
        Three-dimensional ultrasonography in prenatal diagnosis.
        We think that today both three-dimensional ultrasonography and echoplanar imaging could give important additional information to the physician and that in future the general availability of these techniques as well as aspects on safety and costs will decide which imaging technique will gain importance for routine use.
        Andreas Lee, MD, Josef Deutinger, MD, Gerhard Bernaschek, MD, Department of Prenatal Diagnosis and Therapy, AKH University Hospital Vienna, Waehringer Guertel 18-20, 1090 Vienna,
        6/8/82734
        NO LABEL6/8/82734

        References

          • Lee A
          • et al.
          Three dimensional ultrasound: abnormalities of the fetal face in surface and volume rendering mode.
          Br J Obstet Gynaecol. 1995; 102: 302-306
          • Merz E
          • Bahlmann F
          • Weber G
          • Macchiella D.
          Three-dimensional ultrasonography in prenatal diagnosis.
          J Perinat Med. 1995; 23: 213-222