|
|
 |
 |
 |
|
|
|||
|
||||
|
||||
Re: Soft markers for genetic problems - abstractsFrom: Latha Natarajan (nattu@bgl.vsnl.net.in)Tue Dec 16 11:32:01 2003
Hi all, A few abstracts from pubmed. Hope this helps, Latha Natarajan ( LN ), Bangalore, India. 1: Prenat Diagn. 2002 Dec;22(13):1233-7. Related Articles, Links Nuchal index: a gestational age independent ultrasound marker for the detection of Down syndrome. Lim KI, Pugash D, Dansereau J, Wilson RD. University of British Columbia, Canada. klim@cw.bc.ca OBJECTIVES: To determine if the ultrasound marker Nuchal Index (NIx) is gestational age independent, and to determine its specificity and sensitivity for Down syndrome (DS) identification. METHODS: Prospective cohort. A prospective database of fetal biometry and soft markers of aneuploidy was searched for fetuses with the following criteria: confirmed gestational age, at least two measurements of nuchal thickness and biparietal diameter, no major detectable fetal anomalies, and either normal karyotype or normal postnatal exam. Nuchal Index (NIx) was defined as 100x (mean nuchal thickness [mm])/(mean Biparietal Diameter [mm]). This cohort was divided into two groups according to the last digit of their hospital unit number. Initial analysis was carried out in the first group (analysis group), with the second group (normal) used to test the results. A prospective cohort of pre- and postnatally diagnosed DS fetuses with at least two measurements of nuchal thickness and biparietal diameter constituted the abnormal study group (abnormal) and was used to determine the sensitivity of the index. P value <0.05 was considered significant. RESULTS: Eight hundred and seventy-five fetuses constituted the control group with 455 in the analysis group and 420 in the normal group. In the analysis group, Pearson coefficient and ANOVA confirm that NIx was independent of gestational age between 14 + 0 and 22 + 6 weeks of gestation. For the analysis group, mean NIx was 7.72, (SD = 2.05) and a threshold value of 11.0 yielded a specificity of 94%. Fifty-two DS fetuses made up the abnormal group. Mean NIx in this group was 17.9 (SD = 13.9), which was highly significant (P < 0.00001) compared to the analysis group. Using an NIx threshold of 11.0, sensitivity for any DS was 61.5% (32/52) and specificity (normal group) was 96% (402/420) (False positive rate = 4%). If DS fetuses with effusions, hydrops, cystic hygromas or central nervous system (CNS) defects are excluded, the sensitivity for an NIx of 11.0 was 50.0% (20/40). CONCLUSIONS: Nuchal Index (NIx) can be assumed to be constant between 14 + 0 and 22 + 6. Using a threshold of 11.0, the sensitivity for any Down syndrome (DS) fetus was 62% (32/52) with a specificity of 96% (False positive rate = 4%). Even when obvious fetal conditions that can cause an increase in NIx are excluded, the sensitivity remains acceptable at 50%. NIx appears to be a useful, gestational age independent ultrasound marker for Down syndrome. Copyright 2002 John Wiley & Sons, Ltd. J Ultrasound Med. 2001 Oct;20(10):1053-63. Related Articles, Links Isolated sonographic markers for detection of fetal Down syndrome in the second trimester of pregnancy. Nyberg DA, Souter VL, El-Bastawissi A, Young S, Luthhardt F, Luthy DA. Seattle Ultrasound Associates, Washington 98115, USA. OBJECTIVE: To determine whether sonographic "markers" are associated with fetal Down syndrome during the second trimester and to estimate the degree of risk of individual markers using likelihood ratios. METHODS: Second-trimester (14-20 weeks) sonographic findings in 186 fetuses with trisomy 21 were compared with a control group of 8728 consecutive control fetuses. Six markers were evaluated: nuchal thickening, hyperechoic bowel, shortened femur, shortened humerus, echogenic intracardiac focus, and renal pyelectasis. RESULTS: Major or structural abnormalities were observed in 31 fetuses with trisomy 21 (16.7%) and 53 control fetuses (0.6%) (P< .001). Some type of sonographic finding (major abnormality, minor marker, or both) was observed in 68.8% of fetuses with trisomy 21 compared with 13.6% of control fetuses (P < .001). An isolated minor or "soft" marker was the only sonographic finding in 42 (22.6%) of 186 fetuses with trisomy 21 compared with 987 (11.3%) of 8728 control fetuses (P < .001). Nuchal thickening (P < .001; likelihood ratio, 11) and hyperechoic bowel (P < .001; likelihood ratio, 6.7) showed the strongest association with trisomy 21 as isolated markers, followed by shortened humerus (likelihood ratio, 5.1), echogenic intracardiac focus (likelihood ratio, 1.8), shortened femur (likelihood ratio, 1.5), and pyelectasis (likelihood ratio, 1.5). Echogenic intracardiac focus was the single most common isolated marker in both affected fetuses (7.1%) and control fetuses (3.9%) but carried a low risk (P= .046; likelihood ratio, 1.8). CONCLUSIONS: A single soft marker is commonly encountered during the second trimester among fetuses with trisomy 21. The risk of fetal Down syndrome, reflected by likelihood ratios, was determined for 6 individual markers. This information can be combined with the a priori risk to estimate the individual patient risk for fetal Down syndrome. PMID: 11587012 [PubMed - indexed for MEDLINE] Ultrasound Obstet Gynecol. 1998 Dec;12(6):385-90. Related Articles, Links The significance of choroid plexus cysts, echogenic heart foci and renal pyelectasis in the first trimester. Whitlow BJ, Lazanakis ML, Kadir RA, Chatzipapas I, Economides DL. Fetal Medicine Unit, Royal Free Hospital, London, UK. OBJECTIVE: To determine the significance of certain soft ultrasonographic markers for chromosomal abnormalities in the first trimester. DESIGN: This was a prospective cross-sectional study. SETTING: University Department of Obstetrics and Gynaecology, London, UK. METHODS: A total of 5385 women from an unselected population underwent a detailed assessment of fetal anatomy at 11-14 weeks of gestation (confirmed by crown-rump length) by transabdominal sonography (5.0 MHz) and transvaginal sonography (6.0 MHz) when necessary. RESULTS: In normal fetuses, the prevalences of choroid plexus cysts, pyelectasis and echogenic heart foci were 2.2, 0.9 and 0.6%, respectively in the first trimester and 2.0, 0.8 and 0.8%, respectively in the second trimester. Pyelectasis (likelihood ratio = 8.0, p = 0.03) and echogenic heart foci (likelihood ratio = 10.3, p = 0.02) were found to be associated significantly with fetal aneuploidy, while choroid plexus cysts were not. CONCLUSIONS: Although the majority of aneuploidies were detected by increased nuchal translucency and/or the presence of structural abnormalities (78%; 25/32), the use of soft ultrasonographic markers in the first trimester would have increased the overall detection by a further 3%. These data are preliminary and many thousands of pregnancies will need to be examined to determine the significance of the individual markers in different chromosomal abnormalities. PMID: 9918086 [PubMed - indexed for MEDLINE]
>----- Original Message -----
> Dear Terry
> > ----- Original Message -----
|
|
Return to
|
Mail a New Message to the Forum: ultrasound@obgyn.net Forum Administrator: terry.dubose@obgyn.net Report Technical Problems: webmaster@obgyn.net Last Updated: Mon Nov 2 05:35:59 2009 |
The American Medical Association is no longer designating CME hours for AMA Category II CME credit. However, physicians themselves may self designate learning activities as Category II CME credit hours if they feel it is of sufficient educational merit and meets the formal definitions of continuing medical education. OBGYN.net believes these interaction in this forum meets these criteria. For further information see the AMA web site.