Diagnostic Value of Prenatal MR Imaging in the Detection of Brain Malformations in Fetuses before the 26th Week of Gestational Age

Article Figures & Data

Table 1:

Ultrasonographic and clinical indications for prenatal MR imaging

Indications for MR Imaging	No.
Ventricular dilation at US	34
Midline malformation at US	20
Posterior fossa anomalies at US	17
CMV infection	14
TTTS	14
Cysts at US	2
Vascular malformation at US	2
Brain anomalies in previous pregnancy	2
Cortical malformations at US	1
Toxoplasma infection	1
Polymalformation at US	1
Brain edema at US	1

Note:—TTTS indicates twin-to-twin transfusion syndrome; CMV, cytomegalovirus.

Table 2:

Brain malformations detected at postnatal MR imaging

Malformation	No.
Midline malformations
Complete callosal agenesis^{^a}	10
Callosal hypoplasia	9
Partial callosal agenesis	3
Septum pellucidum agenesis	2
Incomplete septum pellucidum	1
Fused thalami	1
Occipital meningocele	1
Disorders of cortical development
Focal polymicrogyria	5
Heterotopias	3
Hemispheric polymicrogyria	2
Anomalous sulcations not of polymicrogyria type^{^b}	2
Arrhinencephaly	1
Schizencephaly	1
Posterior fossa anomalies
Vermian hypoplasia	6
Cerebellar hypoplasia	4
Vermian counterclockwise rotation	4
Malformed brain stem	2
Chiari type I malformation	1
Molar tooth malformation	1
Beaking of the tectum	1
Vascular malformations
Persistent falcine sinus	2
Dural sinus malformation	1
Ventricular/subarachnoid space anomalies
Ventricular dilation	32
Ventricular and pericerebral space dilation^{^c}	6
Dysmorphic ventricles^{^d}	6
Pericerebral space dilation	4

↵a Median diameter of the atrium of the lateral ventricles: 11 mm (range, 9–12 mm).
↵b Dysmorphic gyration pattern, for example, large areas of shallower or deeper sulci without evidence of abnormally small and packed gyri.
↵c Pericerebral CSF space was considered enlarged when the difference between the right-left brain and skull diameters was >10 mm.²⁹
↵d Ventricular shape anomalies, mostly of the frontal horns (On-line Fig 4).