Ultrasound Images of the Normal Brain

and Laurence Loeuillet²

(1)

Centre d’échographie Ambroise Paré, Les Mureaux, France

(2)

Hôpital Cochin, Paris, France

From 8 to 10 GW: Early Morphological Examination

From 8 to 10 gw

8 gw

9 gw

10 gw

Fig. 2.1

Corresponding histology from 8 to 10 gw: (a) 8 gw, (b) 9 gw, (c) 9 gw1/2, (d–f) 10 gw

Anatomical Landmarks

From 8 gw, the falx cerebri is visible (* telencephalic vesicles), and the rhombencephalic vesicle (°) is easily identifiable.
The cranial contours are visible from 9 gw.
The cerebral aqueduct becomes visible (arrow).

From 11 to 13 GW: Early Morphological Examination

11 gw

12 gw

Fig. 2.2

Corresponding histology at 11 gw. (a–c) Coronal sections, (d) axial section

13 gw

Fig. 2.3

Corresponding histology at 12 gw. (a, b) Coronal sections, (c, d) axial sections

Fig. 2.4

Corresponding histology at 13 gw. (a, b) Coronal sections, (c) pathology specimen

Fig. 2.5

Fourth ventricle: histology at 13 gw (coronal sections) V4 intracerebral transluscency, CN cisterna magna

Anatomical Landmarks

The fourth ventricle (yellow arrows) is bordered by closure of the edges of the rhomboencephalic vesicles.
The third ventricle is clearly visible (turquoise arrows).
The upper part of the diencephalon (blue arrow) is visualized between the choroid plexuses of the lateral ventricles.
From week 12, the cerebral cortex can be visualized, and the orientation of Bichat’s fissures is clearly visible (dotted arrow). These fissures are oblique and form an acute angle with a posterior point. No Sylvian fissures are present (pink arrow).
An intracerebral transluscency is visible in the first trimester (Chaoui et al. 2009; Chaoui and Nicolaides 2010): it corresponds to the fourth ventricle; we will see later that its disappearance is suggestive of open spina bifida.

From 14 to 16 GW: Morphological Examination

Fig. 2.6

16w: (a) Triplane, (b) Axial TIU, (c) Coronal TIU, (d) Sagittal TIU

Fig. 2.7

Corresponding specimens and histology at 15 gw

Anatomical Landmarks

14 gw

Anatomical Landmarks

At 14 gw, the cerebellar vermis (green arrow) can be seen behind the fourth ventricle (yellow arrows); the cisterna magna (yellow dotted arrow) can be distinguished behind the cerebellum.
The third ventricle (turquoise arrow) and the upper part of the diencephalon or roof of the third ventricle (blue arrow) are visible.

16 gw

Fig. 2.8

Corresponding specimens and histology at 16 gw: brain (a–d), cerebellum (e dorsal view), (f, g) Sagittal sections

Anatomical Landmarks

At 14 weeks, the fourth ventricle is clearly visible (yellow arrow).
The third ventricle (turquoise arrow) and the upper part of the diencephalon or roof of the third ventricle (blue arrow) are visible.
At 16 gw, the anterior part of the corpus callosum may be visible (orange arrow).

From 18 to 20 GW: Morphological Examination

Fig. 2.9

18 gw: (a) Triplane, (b) Axial TIU, (c) Coronal TIU, (d) Sagittal TIU

Fig. 2.10

Brain at 18 gw: (a) ventral view, (b) lateral view, (c) axial section, (d) sagittal section, (e) coronal section

Fig. 2.11

20 gw: (a) Triplane, (b) Axial TIU, (c) Coronal TIU, (d) Sagittal TIU

Anatomical Landmarks

18 gw

Fig. 2.12

Corresponding ultrasound images and fetal pathology specimens at 18 gw

18 gw

20 gw

Fig. 2.13

Fetal pathology specimen at 18 gw

Anatomical Landmarks

At 18 gw, the corpus callosum (red arrows) is already well developed and is visible in sagittal and coronal images. The Sylvian fissures (yellow arrows) are almost invisible.
At 20 gw, the corpus callosum is clearly visible and can be measured for thickness, length, and echogenicity (red arrows). The large commissures are recognizable by their upward scalloping and their marked echogenicity (green arrows). The Sylvian fissures are still discrete (yellow arrows) (see changes in Sylvian fissures).

20 gw