title: Three- and 4-dimensional ultrasonography in the prenatal evaluation of fetal anomalies associated with trisomy 18.
abstract: OBJECTIVE
  The purpose of this study was to assess the usefulness of 3- and 4-dimensional ultrasonography (3D/4DUS) for the description of anomalies associated with trisomy 18 and to determine whether 3D/4DUS adds diagnostic information over what is provided by conventional 2-dimensional ultrasonography (2DUS) alone.
  
  
  METHODS
  Twenty-six fetuses subsequently proven to have trisomy 18 underwent prenatal ultrasonographic evaluations by both 2DUS and 3D/4DUS. Volume data sets were acquired by the same sonographers after the conventional 2DUS examinations and were explored with 4-dimensional imaging software by another independent examiner blinded to the indications of 2DUS. The findings detected by 2DUS and 3D/4DUS were compared with those acquired at autopsy. The sensitivity of each modality for detecting anomalies was calculated and compared by the McNemar test.
  
  
  RESULTS
  Excluding polyhydramnios, there were 131 anomalies confirmed postnatally in 26 fetuses with trisomy 18. There was a statistically significant difference in the sensitivity for detecting anomalies between 3D/4DUS and 2DUS (93.89% versus 73.28%; McNemar value = 23.31; P < .05), especially in anomalies of the face/neck (96.15% versus 65.38%; McNemar value = 6.13; P < .05) and extremities (96.3% versus 48.15%; McNemar value = 11.07; P < .05). Three- and 4-dimensional ultrasonography provided additional diagnostic information for 83.97% of the anomalies related to trisomy 18 and influenced the obstetric management of 4 fetuses.
  
  
  CONCLUSIONS
  Three- and 4-dimensional ultrasonography offered diagnostic advantages for many anomalies associated with trisomy 18, especially for anomalies of the extremities and face. This modality could be a powerful adjunct to 2DUS in the prenatal anatomic evaluation of fetuses with trisomy 18.
authors.affiliation: Department of Diagnostic Ultrasonography, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zheng
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Zhou
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Zhu
authors.forename: Xi-Lin
authors.initials: XL
authors.lastname: Wang
authors.forename: Yun-Qiu
authors.initials: YQ
authors.lastname: Qian
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Lei
authors.forename: Bi-Liang
authors.initials: BL
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Yu
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Xin
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis; D000293:Adolescent; D000328:Adult; D002887:Chromosomes, Human, Pair 18; D003937:Diagnosis, Differential; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014314:Trisomy / Q000175:diagnosis*; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014741:Video Recording; D055815:Young Adult