Ultrasound appearances of the acrania-anencephaly sequence at 10 to 14 weeks’ gestation

Dagmar Wertaschnigg, Maya Reddy, Jayshree Ramkrishna, Fabricio da Silva Costa, Waldo Sepulveda, Daniel L. Rolnik, Simon Meagher

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5 Citations (Scopus)


Objectives: The acrania-anencephaly sequence is a lethal condition with a high detection rate in experienced hands after 10 weeks’ gestation. However, earlier in gestation, many cases remain undetected. Different phenotypic appearances have been described and might help increase the detection rate in less experienced hands and also earlier in gestation. The purpose of this study was to assess interobserver reliability in classifying cases of the acrania-anencephaly sequence during first trimester in 6 different subtypes according to their ultrasound appearances. Methods: This was a retrospective descriptive cohort study at 3 centers for fetal imaging. Each case was classified according to its phenotypic appearance by 2 independent operators as “bilobular,” “cystic,” “elongated,” “irregular,” “foreshortened,” or “overhanging.” Frequencies of each type are described, and interoperator agreement was assessed with the intraclass correlation coefficient. Results: From the 88 included cases, the frequencies of the different subtypes classified as overhanging, elongated, bilobular, cystic, foreshortened, and irregular were 31%, 25%, 19%, 11%, 8%, and 6%, respectively. The interoperator reliability was good, with an intraclass correlation coefficient of 0.903 (95% confidence interval, 0.853–0.937; P <.001). Conclusions: Using different subtypes may improve the detection of the acrania-anencephaly sequence. An accurate early diagnosis could lead to timely, less traumatic, and safer management of affected pregnancies.

Original languageEnglish
Pages (from-to)1695-1700
Number of pages6
JournalJournal of Ultrasound in Medicine
Issue number9
Publication statusPublished - 1 Sept 2020


  • acrania-anencephaly sequence
  • detection rate
  • first-trimester ultrasound
  • prenatal diagnosis
  • subtype
  • ultrasound appearances

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