Assessment of the Fetal Sylvian Fissure in the Setting of Diffuse Cortical Abnormalities Detection: A Comparison of Published Methods.

Objectives: The aim of this study is to compare the accuracy of the currently published techniques for Sylvian fissure (SF) evaluation on the axial plane in normal fetuses and in fetuses with confirmed diffuse malformation of cortical development (MCD).

Methods: We performed a retrospective study in which the SF was assessed from fetuses between 22 and 33 weeks of gestation on a 2D transabdominal axial plane by means of subjective and objective methods derived from a literature search. The accuracy of the different techniques to predict the presence or the absence of MCD was compared.

Results: 100 fetuses were included at a median gestational age of 26 (22-33) weeks. Of these, 93 fetuses were normal. Subjective evaluation showed 100% (95% CI: 65-100) sensitivity and 100% (95% CI: 96-100) specificity for predicting the absence or presence of MCD. Conversely, when applying objective methods in the evaluation of the SF, the sensitivity ranged from 29% (95% CI: 8-64) to 57% (95% CI: 25-84) and the specificity from 23% (95% CI: 15-32) to 98% (95% CI: 92-100).

Conclusions: The comparison of different methods for the expert assessment of the SF in the axial plane has shown that the subjective evaluation of the SF may be more accurate than other proposed methods in predicting the presence or absence of diffuse MCD. Further prospective research is needed to validate these results in daily practice.