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Phenotypic Characteristics of Absent and Hypoplastic Nasal Bones in Fetuses With Down Syndrome
Author(s) -
Gonçalves Luís F.,
Espinoza Jimmy,
Lee Wesley,
Schoen Mary Lou,
Devers Patricia,
Mazor Moshe,
Chaiworapongsa Tinnakorn,
DeVore Greggory R.,
Romero Roberto
Publication year - 2004
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/jum.2004.23.12.1619
Subject(s) - medicine , nasal bone , ossification , fetus , interquartile range , down syndrome , anatomy , gestational age , skull , coronal plane , confidence interval , pregnancy , biology , psychiatry , genetics
Objective. To determine the frequency and clinical significance of bilateral and unilateral hypoplastic nasal bones for the detection of Down syndrome by 3‐dimensional ultrasonography. Methods. Thirty‐seven volumes of the fetal skull from fetuses with Down syndrome and 37 from fetuses without abnormalities were analyzed by 1 investigator blinded to fetal karyotype. The maximum intensity projection algorithm was used to reconstruct nasal bones. Ossification patterns were identified in anteroposterior and profile views. Sensitivity, false‐positive rates (FPRs), and likelihood ratios (LRs) for detection of Down syndrome were calculated. Results. After exclusions (coronal acquisition [n = 11], hand in front of the face [n = 4], poor imaging [n = 2], incomplete follow‐up [n = 2], and anomalies detected after delivery [n = 2]), 53 volumes were analyzed (26 fetuses with Down syndrome and 27 without abnormalities; median gestational age, 21 6/7 weeks [interquartile range, 19 6/7–25 2/7 weeks]). Rendered profile views revealed absent nasal bones in 18.9% (10 of 53) of the fetuses, and, among these, 90% (9 of 10) had Down syndrome (sensitivity, 34.6% [9 of 26]; FPR, 3.7% [1 of 27]; LR, 9.3 [95% confidence interval (CI), 1.3–68.7]). Three ossification patterns were identified in anteroposterior views: (1) normally developed, (2) delayed ossification, and (3) absent nasal bones. Sensitivity, FPR, and LR of absent nasal bones for detecting Down syndrome were 34.6% (9 of 26), 3.7% (1 of 27), and 9.0 (95% CI, 1.3–68.7), respectively. Sensitivity, FPR, and LR of delayed ossification for detecting Down syndrome were 42.3% (11 of 26), 22% (6 of 27), and 1.83 (95% CI, 0.8–4.4). Conclusions. Absence of nasal bones is associated with the highest risk of Down syndrome. Delayed ossification is associated with a lower risk of Down syndrome than absent nasal bones. These ossification patterns may be indistinguishable on 2‐dimensional ultrasonography.