Beyond fetal magnetic resonance diagnosis of corpus callosum agenesis

Abstract

Background Corpus callosum agenesis (CCA) is a midline congenital anomaly. Routine prenatal 2D ultrasonography (2D US) can suggest CCA. A definitive diagnosis and identification of more subtle associated neurological or non-neurological abnormalities are difficult to be detected by prenatal 2D US; therefore, a further study by fetal magnetic resonance imaging (MRI) is needed. This study highlights the role and evaluates the diagnostic value of fetal MRI in the diagnosis of CCA and identifying the associated anomalies, which is a prognostic of the postnatal developmental outcome. Results Out of 27 fetuses that were suspected to have CCA on prenatal US, fetal MRI diagnosed 25/27 fetuses (92.5%) with CCA, while the last 2/27 (7.5%) were ruled out; being false positive (FP) on prenatal US, they had normal corpus callosum (CC). Cases diagnosed as CCA were either complete 77.7% (n = 21) or partial agenesis 14.8% (n = 4). They were classified as followed: Only 5/25 (18.5%) had isolated CCA, while the majority 20/25 (74%) of CCA were complex form associated with other anomalies (most of them 14 cases (70%) associated with other neurological anomalies, while 4 cases (20%) associated with other non-neurological anomalies, and last 2 cases (10%) were having both anomalies). The diagnostic performance of fetal MRI in diagnosis of CCA was as follows: sensitivity 100%, specificity 67%, positive predictive value (PPV) 96%, negative predictive value (NPV) 100%, and accuracy 96.3%. The sensitivity of the detection of associated neurological abnormalities was 100% by fetal MRI for 75% by 2D US. Conclusion The prevalence of the complex CCA is higher than the isolated form. Fetal MRI is a valuable adjunctive complementary imaging to prenatal 2D US with high diagnostic performance in the diagnosis of fetuses with CCA. It confirms the diagnosis, assesses the extent of agenesis, and detects coexisting anomalies, which is a prognostic of the postnatal developmental outcome.

Fetal corpus callosum abnormalities: Ultrasound and magnetic resonance imaging role

“…Comparing the results of the above‐mentioned studies 62–64 might suggest that MRI is less helpful in detecting associated anomalies when an isolated ACC is suggested by US. Moreover, in D'Antonio et al's study, related anomalies were found only at birth and missed at both prenatal US and MRI in 3.9% of cases 64 .…”

“…Sotiriadis et al showed that MRI can find additional abnormalities in 22.5% of cases of ACC, compared to US, especially for cortical malformations and heterotopies 36 . Ibrahim et al in a study performed on 27 fetuses suspected of ACC on a prenatal US, reported 100% and 75% for fetal MRI and 2D US regarding the sensitivity of the detection of associated neurological abnormalities, respectively 62 . Recently, D'Antonio et al investigated prenatal MRI role in fetuses with CC isolated anomalies in US and showed that MRI can identify 11.2% of additional anomalies which were mainly the malformations of cortical development (Figure 16).…”

“…In a recent study by nonetheless, a definitive cACC diagnosis is obtained with more feasibility, sensitivity, and specificity by MRI. 61,62 However, sometimes even during the third trimester, a second-look targeted US can confirm a suspected CC abnormality on MRI or can even find subtle dysgenesis better than MRI (Figure 15). A recent study by Ghasemi et al…”

“…for fetal MRI and 2D US regarding the sensitivity of the detection of associated neurological abnormalities, respectively. 62 Recently, D'Antonio et al…”

“…investigated prenatal MRI role in fetuses with CC isolated anomalies in US and showed that MRI can identify 11.2% of additional anomalies which were mainly the malformations of cortical development (Figure 16). 64 Comparing the results of the above-mentioned studies [62][63][64] might suggest that MRI is less helpful in detecting associated anomalies when an isolated ACC is suggested by US. Moreover, in D'Antonio et al's study, related anomalies were found only at birth and missed at both prenatal US and MRI in 3.9% of cases.…”