Accuracy of qualitative and quantitative cranial ultrasonographic markers in first trimester screening for open spina bifida and other posterior brain defects: a systematic review and meta-analysis.

BACKGROUND: The significant number of qualitative and quantitative ultrasound markers described for first-trimester screening of open spina bifida (OSB) and other posterior brain defects (oPBD) have resulted in their complex implementation and interpretation for a widespread screening and in a lack of consensus regarding diagnostic accuracy.

OBJECTIVES: To assess and compare the accuracy of qualitative and quantitative cranial sonographic markers at 11-14 weeks for the detection of OSB and oPBD.

SEARCH STRATEGY: A systematic literature search was performed in MEDLINE and COCHRANE from 2009 to April 2020.

SELECTION CRITERIA: Studies assessing the diagnostic accuracy of quantitative and/or qualitative ultrasound signs to predict OSB and oPBD were included. Cohort studies and case-control studies were also considered.

DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed the risk of bias. The overall pooled estimate and a summary ROC curve was estimated for each subgroup (qualitative and quantitative assessment).

MAIN RESULTS: Twenty-three studies were included in our meta-analysis. The pooled sensitivity and specificity for qualitative assessment was 76.5% and 99.6%, and for quantitative assessment was 84.5% and 96.3%, respectively; specificity for the qualitative ultrasound signs was significantly higher (p=0.001). The overall sensitivity of cranial sonographic markers for the screening of oPBD was 76.7% and specificity was 97.5%.

CONCLUSIONS: Since the qualitative approach demonstrated greater specificity, this would therefore appear to be more appropriate for daily screening, as a first-line tool, whereas the quantitative approach should be reserved for expert ultrasound.