Holoprosencephaly

MARINA DEL REY, CALIF. -- Three dimensional ultrasound images capture data about the uterus and fetus that are unavailable with standard two-dimensional ultrasound, Dr. Lawrence D. Platt said at a conference on ultrasound and women's health.

The value of 3-D ultrasound to the obstetrician is the ability to visualize, rotate, and view images of the fetus, uterus, and surrounding anatomy on three planes simultaneously, helping identify or confirm abnormalities of the fetus, uterus, or other pelvic organs.

Speakers at the meeting who have participated in early research with 3-D ultrasound endorsed the technology as an important tool to help manage problem pregnancies and prepare for delivery.

Being able to more accurately visualize how some abnormalities will appear after birth also helps families make crucial decisions about the management of pregnancy and prepare for the special needs of the child, said Dr. Platt, chairman of the department of ob.gyn. at Cedars-Sinai Medical Center and professor of ob.gyn. at the University of California, Los Angeles.

In addition, the "wow effect" of the high resolution, sculpturelike images pleases pregnant women and their families, who often want copies of the images to frame or send over the Internet, Dr. Platt said at the meeting sponsored by the American Institute of Ultrasound in Medicine.

Patients like the fact that there is no need to manually move the probe. The 3 D transvaginal or transabdominal transducer scan remains stationary while a built-in "sweep" gathers the data. Imaging can be accomplished in 3 seconds.

Digital storing of the data: makes it available for immediate viewing and for review after the patient has left the office, said Dr. Platt, who believes that 3-D imaging will eventually become an integral part of every obstetrical examination.

In addition to the sagittal and transverse images available with 2-D ultrasound, the third-dimension c-plane helps improve volume measured and provides unique information about the fetus and possible abnormalities in areas such as the following:

* Nuchal translucency. While fetal position can make studies difficult with both standard and 3-D ultrasound, measurements achieved using three planes are more accurate than with two planes, as demonstrated in a recent study of 120 pregnant women. Prenatal measurements of nuchal translucency using 3-D ultra- sound accurately identified all fetuses with congenital abnormalities, but standard ultrasound had only an 85% accuracy rate (J. Perinat. Med. 27[2]:97-102, 1999). Three-dimensional ultrasound, with its midsagittal section of the fetus, provides a clear distinction of the nuchal region from the amniotic membrane that is not as easily obtainable with 2-D ultrasound.

* Fetal brain and cranial structure imaging. Viewing the fetus through the fontanelle using the 3-D endovaginal probe provides an optimal window for imaging fetal brain anatomy, including enlarged ventricles and posterior fossa abnormalities not available with standard ultrasound. The 3-D images of the skull are superior to the conventional 2-D view that is often limited to the cranial sutures due to the natural curvature of the skull.

* Evaluation of the spine. The ability to visualize the fetal spineimage in three or thogonal scan planes enables the detection of vertebrae widening, exact spatial relationships, and the exact level of any spinal defects.

* Cleft lip and palate. These are difficult diagnoses to make with 2-D ultrasound, because the face has a natural curvature that cannot be seen in its entirety. With 3 D ultrasound, these subtle anomalies are projected frontally on an image that can be rotated and analyzed on a computer display screen. Other features of the face, lips, tooth buds, chin, ears, nose, and eyes can also be viewed from different perspectives with 3-D ultrasound.

* Fetal abdominal wall defects. Three-dimensional images capture herniated loops of the small and large intestine associated with gastroschisis, enabling the physician to differentiate gastroschisis from other abnormalities such as bladder exstrophy.

* Placental evaluation. The 3-D display enables visualization of placental changes, including calcifications, placental "lakes," indentations of the chorionic plate, and changes in gray-scale echogenicity. The 3 D display also helps to identify abnormal position, abruption, hematoma, and accreta. This capability is especially helpful in evaluating membranes and other anatomical relationships in twin gestations.

* Umbilical cord assessment. Three dimensional imaging enables easy visualization of the most common abnormality of the umbilical cord, the presence of a single umbilical artery, or "two-vessel cord" as well as the placental insertion. It can help rule out abnormalities associated with the two-vessel cord, such as cardiac defects, holoprosencephaly, skeletal dysplasia, hydrocephalus, omphalocele, and diaphragmatic hernia.

COPYRIGHT 2001 International Medical News Group
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