Nomograms of the Fetal Sylvian Fissure and Insular Lobe throughout Gestation: A Multicentric, Ultrasonographic Cross-Sectional Study

Abstract

Introduction: Anomalies in cortical development are often associated with an adverse outcome, but prenatal diagnosis is often impeded by the limited knowledge about normal sulci biometries throughout fetal brain development. Our aim was to provide two-dimensional ultrasonographical (2D US) nomograms of the depth of the Sylvian fissure (SF) and insular lobe (IL), as well as of the SF ratio throughout gestation in a large number of fetuses. Materials and Methods: This was a prospective cross-sectional study of 329 normal singleton pregnancies. Measurements of the SF, IL, and SF ratio were obtained in a standard transthalamic plane of the fetal head. The SF ratio was defined as SF\SF + IL. All measurements were expressed by regression equations as a function of gestational age (GA) according to the method described by Royston and Wright. The first 38 measurements were repeated twice by 2 examiners to assess the reproducibility through the intraclass correlation coefficient (ICC). Results: A significant correlation was found between GA and SF (r = 0.79; p < 0.0001) as well as IL (r = 0.77; p < 0.0001). Similarly, the SF ratio also showed a significant correlation with GA (r = 0.39; p < 0.0001). When interobserver variability was assessed, ICC was 0.97. Conclusions: Prenatal 2D US measurements of SF and IL as well as the SF ratio may be feasible and reproducible using a standard view of the fetal head. Our nomograms may be used as a reference for assessing cortical development throughout pregnancy.

A Systematic Review of Methodology Used in Studies Aimed at Creating Charts of Fetal Brain Structures

“…Excluded studies and reasons for exclusion are reported in Table S3 . Finally, 42 studies, reported between January 1970 and 2021, met the inclusion criteria, and these provided data for 45,626 fetuses, included in the final analysis ( Table 1 ) [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. The median sample size of participating fetuses was 372.5 (range: 50 to 8313; 25th percentile: 175.8; 75th percentile: 709.3).…”

“…Nine studies reported more than one fetal brain structure [ 9 , 10 , 17 , 32 , 34 , 36 , 41 , 42 , 43 ]. In addition, 4 studies reported charts for POF [ 9 , 10 , 17 , 36 ], 6 for SF [ 9 , 10 , 17 , 35 , 36 , 44 ], 3 for AV [ 22 , 36 , 43 ], 14 for PV [ 7 , 8 , 14 , 19 , 23 , 26 , 27 , 30 , 32 , 34 , 36 , 38 , 40 , 43 ], 20 for TCD [ 12 , 15 , 16 , 18 , 20 , 21 , 24 , 25 , 28 , 31 , 32 , 34 , 39 , 41 , 42 , 43 , 45 ,…”

“…The reason for this high source for bias identified in these fields is also probably related to the retrospective design (around 30% of the studies). Furthermore, in only four studies sample size estimation was performed [ 18 , 36 , 39 , 44 ], and only three studies had population-based sample selection [ 36 , 39 , 47 ], with all other studies reporting either convenience sampling or arbitrary recruitment or sampling methods that were not reported ( Figure 2 ).…”

Abnormal degree centrality can be a potential imaging biomarker in first-episode, drug-naive bipolar mania

“…The parahippocampal gyrus is located at the bottom of the lateral groove, and the surrounding round groove is separated from the frontal lobe, temporal lobe, and head lobe. The function may have visceral autonomic nerve and Guam leaf damage, which may cause emotional instability, language disorder, hallucinations, and other mental symptoms [25]. According to the fMRI study, an AlFF increase on both sides of the bipolar disorder, down to both sides of the bipolar disorder, extending to the body of the body, right SFGmed and right superior temporal gyrus (STG) [26].…”

Prenatal sonographic assessment of Sylvian fissure operculization (SFO): importance of distinguishing between screening and diagnostic tools and selecting precise anatomical landmarks

“…Recently, Poon et al 1 and Pooh et al 2 published interesting studies on an objective approach to analyze the operculization of the Sylvian fissure (SF) based on transvaginal coronal sections at 18-30 weeks of gestation. These studies were an extension of previously published reports 3,4 which aimed to help imaging physicians in screening for and/or the diagnosis of cerebral or cortical anomalies, using an objective approach based on anatomical structural measurements.…”