Methods of prenatal screening for trisomy 21
View Patent ↗Methods for prenatal screening for trisomy 21 employ examination of the fronto-maxillary facial (FMF) angle of a fetus. The methods may comprise obtaining a two or three dimensional image of a fetal face, measuring the FMF bone angle and/or FMF skin angle on the image, and comparing the measured FMF bone angle and/or FMF skin angle with an FMF bone angle and/or FMF skin angle characteristic of chromosomally normal fetuses. A measured FMF bone angle and/or FMF skin angle greater than the FMF bone angle and/or FMF skin angle characteristic of chromosomally normal fetuses provides an indication of an increased likelihood of the occurrence of trisomy 21 in the fetus.
1. A method for prenatal screening for trisomy 21 using an ultrasound imaging system comprising an ultrasound device and a computing device, the method comprising: obtaining a two or three dimensional image of a fetal face using the ultrasound device, measuring a FMF bone angle on the image using the computing device, wherein the FMF bone angle is the angle between a line extending along an upper aspect of a maxilla and a line extending from an anterior aspect of the maxilla to an external surface of a frontal bone at its point of greatest anterior excursion (the FMF bone angle), and comparing the measured FMF bone angle with an FMF bone angle characteristic of chromosomally normal fetuses using the computing device to provide an indication of an occurrence of trisomy 21 in a fetus, wherein a measured FMF bone angle greater than the FMF bone angle characteristic of chromosomally normal fetuses provides an indication of an increased likelihood of the occurrence of trisomy 21 in the fetus.
2. The method of claim 1 , wherein the ultrasound device is a three dimensional ultrasound device.
3. The method of claim 2 , wherein the image comprises a mid-sagittal view of the fetal face.
4. The method of claim 1 , wherein the image is obtained from a fetus at 10 or greater weeks of gestation.
5. The method of claim 1 , wherein the image is obtained from a fetus at 10-19 weeks of gestation.
6. The method of claim 1 , wherein the image is obtained from a fetus at 10-13 weeks of gestation.
7. The method of claim 1 , wherein the image is obtained from a fetus at 14-23 weeks of gestation.
8. The method of claim 1 , wherein a measured FMF bone angle of greater than 80° indicates an increased likelihood of the occurrence of trisomy 21.
9. The method of claim 1 , wherein a measured FMF bone angle of greater than 90° indicates an increased likelihood of the occurrence of trisomy 21.
10. The method of claim 1 , wherein the FMF bone angle is the angle between a line extending along an upper aspect of a maxilla and a vomer bone and a line extending from an anterior aspect of the maxilla to an external surface of a frontal bone at its point of greatest anterior excursion.
11. A method for prenatal screening for trisomy 21 in a fetus at 14-23 weeks of gestation using an ultrasound imaging system comprising an ultrasound device and a computing device, the method comprising: obtaining a two or three dimensional image of a fetal face using the ultrasound device, measuring a FMF skin angle on the image using the computing device, wherein the FMF skin angle is the angle between a line extending along an upper aspect of a maxilla and a line extending from an anterior aspect of the maxilla to an external skin surface along a frontal bone at its point of greatest anterior excursion (the FMF skin angle), and comparing the measured FMF skin angle with an FMF skin angle characteristic of chromosomally normal fetuses using the computing device to provide an indication of an occurrence of trisomy 21 in a fetus, wherein a measured FMF skin angle greater than the FMF skin angle characteristic of chromosomally normal fetuses provides an indication of a likelihood of the occurrence of trisomy 21 in the fetus.
12. The method of claim 11 , wherein the ultrasound device is a three dimensional ultrasound device.
13. The method of claim 12 , wherein the image comprises a mid-sagittal view of the fetal face.
14. The method of claim 11 , wherein a measured FMF skin angle of greater than 80° indicates an increased likelihood of the occurrence of trisomy 21.
15. The method of claim 11 , wherein a measured FMF skin angle of greater than 85° indicates an increased likelihood of the occurrence of trisomy 21.
16. The method of claim 11 , wherein the FMF skin angle is the angle between a line extending along an upper aspect of a maxilla and a vomer bone and a line extending from an anterior aspect of the maxilla to an external skin surface along a frontal bone at its point of greatest anterior excursion.
17. The method of claim 11 , further comprising measuring a FMF bone angle on the image using a computing device, wherein the FMF bone angle is the angle between a line extending along the upper aspect of the maxilla and a line extending from the anterior aspect of the maxilla to an external surface of a frontal bone at its point of greatest anterior excursion (the FMF bone angle), and comparing the measured FMF bone angle with an FMF bone angle characteristic of chromosomally normal fetuses using a computing device to provide an indication of an occurrence of trisomy 21 in a fetus, wherein a measured FMF bone angle greater than the FMF bone angle characteristic of chromosomally normal fetuses provides an indication of an increased likelihood of the occurrence of trisomy 21 in the fetus.
18. The method of claim 17 , wherein the FMF bone angle is measured from an image obtained from the fetus at 10-13 weeks of gestation.
19. The method of claim 18 , wherein the ultrasound device is a three dimensional ultrasound device.