Ultrasound evaluation of fetal nasal bone at 11 to 14 weeks in a consecutive series of 1906 fetuses

Abstract

Nasal bone evaluation may improve the detection of trisomy 21 in the first trimester in an unselected obstetric population. Although numerically limited, our experience confirms that delayed nasal bone ossification (hypoplasia/absence of nasal bone) is rarely observed in chromosomally normal fetuses (1.4%). An appropriate training of operators is mandatory in order to achieve an acceptable performance.

Normative values of fetal nasal bone lengths of Turkish singleton pregnancies in the first trimester

“…Experience has been shown to be an important factor for the use of the nasal bone as an additional sonographic marker in first trimester screening (10)(11)(12)(13)(14). In most of the previous studies determining the presence of nasal bone for screen- (4,8,(14)(15)(16)(17)(18). However, in these studies the determination ratio of trisomy 21 varied between 60% to 80% (4,8,(14)(15)(16)(17)(18).…”

“…In most of the previous studies determining the presence of nasal bone for screen- (4,8,(14)(15)(16)(17)(18). However, in these studies the determination ratio of trisomy 21 varied between 60% to 80% (4,8,(14)(15)(16)(17)(18). The ossification of the vomeral bone begins with two bilateral ossification centers before ossification of the nasal bone and then these two bilateral ossification centers fuse caudally below the cartilaginous nasal septum, changing into a U-shaped bone when observed in the coronal plane (1).…”

Evaluating the Efficiency of Using Second-Trimester Nasal Bone Hypoplasia as a Single or a Combined Marker for Fetal Aneuploidy

“…[1][2][3][4][5][6][7][8][9][10][11] These studies have used several definitions of NB hypoplasia making generalizability problematic. In a recent study limited to women having prenatal diagnosis, we reported that a ratio of the biparietal diameter (BPD) to NB of greater than 11.0 was the best definition of NB hypoplasia associated with aneuploidy.…”

Investigation of Bone Ratios for Prenatal Fetal Assessment in Taiwanese Population

“…It has been reported that about 65% of Down syndrome fetuses have absent or short NB in fetal NB screening at the first and second trimesters [4]. Only 1~2% of normal karyotype fetuses have been observed [5][6][7]. Down syndrome and absent or hypoplastic fetal NB show similar evidence of high sensitivity, high specificity, and low false-positive rate for Down syndrome screening by fetal NB examination [8][9][10][11].…”