Fetal Brain Midline Structure Measurements: Cavum Septi Pellucidi and Corpus Callosum Indices in Multiple Views at...

Few studies evaluated cavum septum pellucidum (CSP) and corpus callosum (CC) indices in late gestation. This study assessed CSP and CC indices, along with frontal lobe measurements, and examined correlations among parameters.

A cross-sectional study was conducted at Imam Khomeini Hospital Complex on 150 fetuses at ≥36 weeks' gestation. Transabdominal ultrasound was used to measure CSP length, width, trace length, and area in the axial view; frontal lobe thickness from anterior and posterior CSP margins in horizontal and vertical directions; and CC lengths and thicknesses. CSP trace length and area were also obtained in the midsagittal view. Data were analyzed using SPSS 23.

Mean gestational age, biparietal diameter (BPD), head circumference (HC), and estimated fetal weight (EFW) were 37.56±1.08 weeks, 90.73±3.20 mm, 326.58±10.59 mm, and 2987.82±333.68 gr. In the trans-thalamic view, median CSP length, width, trace length, and area were 8.92 mm, 6.05 mm, 2.81 mm, and 0.49 mm ². Median CSP height in the coronal view was 5.85 mm. In the midsagittal view, mean CC outer-to-outer length, inner-to-inner length, CSP trace length, and CSP area were 41.31±4.81 mm, 29.73±4.17 mm, 2.56±0.63 mm, and 0.36±0.19 mm ². All CC and CSP indices correlated significantly with HC (p<0.05). Frontal bone-to-CSP anterior and posterior distances in axial and near-field views also correlated with HC (p=0.0001).

This study provides normative measurements for CC, CSP, and frontal lobe indices at ≥36 weeks' gestation. These values support late-gestation brain assessment and early identification of newborns potentially at risk for neurodevelopmental concerns.