Femur length in the US prediction of trisomy 21 and other chromosomal abnormalities

Article Abstract:

Down syndrome and other chromosomal defects are more likely to affect the fetus in pregnancies of women older than 35 years of age, yet 75 percent of Down syndrome babies are born to mothers younger than 35. This is because there are many more pregnancies in the younger group. Only the older women routinely undergo amniocentesis, a test in which fluid obtained from the amniotic sac during pregnancy is tested for fetal chromosomal abnormalities. The risk of chromosomally abnormal pregnancies is too low in the younger women to justify routine amniocentesis. At the same time, most of the younger women do undergo ultrasound (US) imaging early in pregnancy for reasons other than detecting chromosomal abnormalities in the fetus. It would be highly useful if an indicator of fetal chromosomal abnormalities could be found using the US images that are obtained for other purposes. This study examined using the US images obtained during early pregnancy in a large number of cases to measure the length of the fetal femur (thigh bone). The measurements were then compared with expected femur length to calculate a ratio. Ratios were compared with pregnancy outcomes to see if ratios differed between normal fetuses and those in which chromosomal abnormalities existed. Results were available for 441 fetuses, 428 normal and 13 with chromosomal abnormalities. Ratios were 1.0 for the normal fetuses and 0.94 for the fetuses with chromosomal abnormalities, a significant difference. When a ratio of 0.90 or less was used, the chances for a pregnancy involving chromosomal abnormalities was 3 percent. This level of risk would be high enough to justify performing amniocentesis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Usage, Abnormalities, Ultrasound imaging, Diagnosis, Genetic screening, Genetic testing, Down syndrome, Femur

---

Current status of MR imaging contrast agents: special report

Article Abstract:

In 1988 the FDA (Food and Drug Administration) approved the first brain contrast agent for use with magnetic resonance (MR) imaging. Since then this contrast agent, gadopentetate dimeglumine, has been adopted for several other uses. Three adverse reactions to the use of gadopentetate dimeglumine are of concern: seizures, vomiting, and death. The incidence of seizures in the first hour after administration of this contrast agent is about one in 1,000 enhanced MR studies. The frequency of vomiting is similar. One death has been reported in the US which was associated with the use of gadopentetate dimeglumine. In addition to MR imaging of the brain, this contrast agent (sold by several companies under different brand names) is also being used for MR imaging of other anatomical regions of the body. MR imaging contrast agents are being intensively studied in clinical settings in the U.S.; many more of these agents will be approved for use within the next few years. As they enter the market it will be important to monitor their use and record incidents of adverse reactions in patients. The impact of these new contrast agents, both in economic and medical terms, could have a profound impact on the selection and use of MR imaging hardware in the next few years.

Case studies, Evaluation, Product/Service Evaluation, Physiological aspects, Brain, Magnetic resonance imaging, Contrast media, Contrast media (Chemicals), Diagnostic imaging, Gadolinium, Magnevist (Medication)

---

Similar abstracts:

• Abstracts: Developmental outcome of preterm infants with transient neuromotor abnormalities. A controlled trial of dexamethasone in preterm infants at high risk for bronchopulmonary dysplasia
• Abstracts: Recommendations for the prevention of malaria among travelers. The spread of chloroquine-resistant malaria in Africa: implications for travelers
• Abstracts: Distal-end esophagostomy of the excluded esophagus in the palliation of upper and mid-esophageal carcinoma. Management of huge epiphrenic esophageal diverticula
• Abstracts: Differing mechanisms of clotting inhibition by ionic and nonionic contrast agents
• Abstracts: Avascular necrosis of the vertebral body: MR imaging. Herniation pits of the femoral neck: appearance at MR imaging

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.