In utero MR imaging in fetuses at high risk of lissencephaly

Abstract

Objective: Lissencephaly is a rare disorder of cortical developmental, which usually carries increased risk of recurrence in future pregnancies. In this prospective observational study, we wished to test the hypothesis that sulcation patterns can be used to diagnose lissencephaly successfully on in utero MR (iuMR) imaging in the third-trimester but not in the late second-trimester fetus. Methods: Pregnant females were recruited into this study if they had an increased risk of fetal lissencephaly based on a fetus or child with lissencephaly in an earlier pregnancy. All females were offered serial iuMR examinations at one centre and are reported whether they had at least two examinations. The overall recurrence rate of lissencephaly was recorded along with the sulcation patterns of non-affected fetuses. Results: 19 females were recruited with 23 pregnancies. In 3/23 (13%) fetuses, lissencephaly was diagnosed on iuMR and not detected on ultrasonography. In two cases, the diagnosis of lissencephaly was made on second-trimester iuMR imaging-with certainty in one and described as "possible" in the other. Confident diagnoses of lissencephaly were made by 28-week gestation in all three cases. Four fetuses, ultimately shown not to have lissencephaly, were judged to have minor sulcation delay on secondtrimester imaging but became gestational age appropriate in the third trimester. Conclusion: iuMR imaging can identify fetal lissencephaly between 20 and 24 weeks, but false positives should be expected, particularly in the second trimester, and followup imaging later in pregnancy may be required. Advances in knowledge: It is possible to detect fetal lissencephaly between 20-and 24-week gestational age; but, it is considerably easier in the third trimester. As a result, if a fetus has an increased risk of lissencephaly on the basis of family history, it may be necessary to do serial iuMR studies to confirm normality (or abnormality) of the fetal brain.

Advances in genomic diagnosis of a large cohort of Egyptian patients with disorders of sex development

“…The early prenatal identification of fetal anomalies allows for proper parental counseling regarding the expected prognosis and management options and give the opportunity to proceed to in utero MR imaging or genetic testing. Nevertheless, some abnormalities including lissencephaly could not be detected until late pregnancy (20 and 24 weeks) (Williams & Griffiths, 2017). In most Middle Eastern countries, elective pregnancy termination is forbidden unless the life of mother is in imminent danger.…”

Lissencephaly: Clinical and neuroimaging features in children

“…The abnormal features in prenatal US images at 23 weeks are ventriculomegaly and shallow Sylvian fissure 31 . In older gestational ages, other findings are widespread agyria, abnormal insula, corpus callosum, microcephaly, intrauterine growth restriction, and hydramnios 32 . Dobyns et al 15 observed two types of patterns or gradient of severity according to brain MRI imaging findings.…”

Sylvian fossa sonographic measurements in 18 to 23 weeks fetuses with and without cerebral malformations

“…A shallow Sylvian fissure is a clue for the diagnosis of central nervous system malformations in general 13 and is one of the most important findings for the diagnosis of MCD and lissencephaly in particular. 6 Thus far, this has been assessed subjectively in most studies. Indeed, formation of the Sylvian fissure is a complex 3-dimensional process, and we do agree with others that quantification in late gestation is not straightforward.…”