Is the presence of corpus callosum predictable in the first trimester?

Abstract

Corpus callosum agenesis (CCA) is a clinical condition accompanied by various aneuploidy and genetic syndromes. We identified the development of the corpus callosum (CC) in 278 patients before 18 weeks of gestational age by visualising the pericallosal artery (PCA) in the callosal sulcus and changes in the lengths and ratios of the midbrain (MB) and falx (F), which suggested elevation of the third ventricle and thalamus due to CCA in the first trimester. We succeeded in visualising the path of the PCA in 273 patients. As expected, we observed an increase in the lengths of the MB and F throughout the pregnancies. The MB:F ratio was 0.5-0.6, and it was independent of gestational age. In all 278 patients, the MB:F ratio was <0.6 (95th percentile = 0.79). We observed the presence of the CC during anatomical screening at gestational weeks 18-24. Visualisation of the PCA path (98% sensitivity) and calculation of the MB:F ratio <95th percentile (0.79-100% sensitivity) had very high sensitivity that indirectly confirmed the presence of the CC in the first trimester of pregnancy. Impact statement What is already known on this subject: After reading the articles for detecting the absence of corpus callosum (CC) at first trimester with midbrain (MB) and falx (F) measurement by Lachmann et al. ( 2013 ) and visualising pericallosal artery (PCA) as an indirect sign of CC agenesis by Pati et al. ( 2012 ), we aimed to have a look for our records visualising PCA in callosal sulcus and measure MB-F, as well as their ratios for an indirect sign of 'presence' of CC at first trimester. What the results of this study add: In recent literature, it is not possible to find many articles suggesting the presence of CC between 11 and 13 weeks of gestation. Díaz-Guerrero et al. ( 2013 ) and Pati et al. ( 2012 ) has researched visualising PCA path. Lachmann et al. ( 2013 ) reported an article for MB and F measurements in early suspicion of CC agenesis. Our study will be the first article in visualising PCA path and measuring MB-F lengths as well as their ratios for 'presence' of CC with high sensitivity rates (98% and 100%). What are the implications of these findings for clinical practice and/or further research: This study encourages clinicians visualising PCA path and measure MB-F lengths when they will try to visualise repetitive times and see how it is an easy procedure when you get used to it.

Assessment of pericallosal artery at 11–14 weeks of gestation: Cohort study and meta‐analysis

“…3 Furthermore, acquisition of a midsagittal view of the fetal brain is relatively easy in the first trimester of pregnancy because it represents the imaging plane used to measure the NT. Assessment of the PCA with high‐definition color Doppler represent another feasible and reproducible approach to indirectly detect CC in the first trimester of pregnancy and may help in more accurately describing the fetal anatomy in those cases with suspicion of fetal structural or chromosomal anomalies, or to reassure parents with a prior pregnancy complicated by fetal ACC 4–8,21,22 …”

“…Several recent studies reported that the prenatal diagnosis of ACC can be suspected at 11–14 weeks of gestation by identifying an abnormal course of the PCA. However, the small sample size of these studies, differences in type and time at ultrasound assessment as well as the inclusion criteria impair our ability to extrapolate robust evidence on the actual diagnostic performance of first trimester ultrasound in detecting CC abnormalities in the first trimester of pregnancy 4–8 …”

“…However, the small sample size of these studies, differences in type and time at ultrasound assessment as well as the inclusion criteria impair our ability to extrapolate robust evidence on the actual diagnostic performance of first trimester ultrasound in detecting CC abnormalities in the first trimester of pregnancy. [4][5][6][7][8] The primary aim of the study was to report the rate of visualization of the PCA using ultrasound in a large cohort of consecutive pregnancies at 11-14 weeks. The secondary aim was to conduct a systematic review reporting the overall visualization of PCA in the published literature.…”

Scoping Review of the Prenatal Diagnosis of Agenesis of the Corpus Callosum

“…The search for an earlier diagnosis was undertaken and included the assessment of the visualization of the pericallosal artery (Diaz-Guerrero et al, 2013;Kalayci et al, 2018) and of the midbrain and flax diameters as potential early markers of ACC (Kalayci et al, 2018;Lachmann et al, 2013). However, a premature diagnosis of partial ACC was cautioned given the rate of misdiagnosis and the subsequent psychological burden (Min, et al 2020).…”

Visualization of the Third Ventricle, the Future Cavum Septi Pellucidi, and the Cavum Veli Interpositi at 11+3 to 13+6 Gestational Weeks on 3D Transvaginal Ultrasound Including Normative Data

“…14 mainly related to the corpus callosum and only showed indirect signs reflecting its presence or absence. Lachman et al[23] use the ratio midbrain and falx diameter, Pati et al[24] use the visualization and measurement of the pericallosal artery, and Kalayci et al[25] use a combination of both methods for indirect diagnosis of an absent corpus callosum.The current study demonstrates the feasibility of displaying the sagittal section of the third ventricle, fcsp, roof/cvi, commissural ▶ Fig.6cvi prediction interval (cavum veli interpositi ap/ccmm).▶ Fig.7csp prediction interval (cavum septum pellucidum ap/ccmm).…”