Neonatal neurosonography: A pictorial essay

Abstract

Neurosonography is a simple, established non-invasive technique for the intracranial assessment of preterm neonate. Apart from established indication in the evaluation of periventricular haemorrhage, it provides clue to wide range of pathology. This presentation provides a quick roadmap to the technique, imaging anatomy and spectrum of pathological imaging appearances encountered in neonates.

Keywords: Cranial USG; germinal matrix haemorrhage; neurosonography.

Figure 1

Diagrammatic illustration showing the size of fontanellae limiting the sonographic window

Figure 2

Anatomical picture of the anterior fontenellae; size variation in normal neonates as shown by CT volume-rendered reconstruction

Figure 3

Illustration of coronal USG examination, showing frontal and posterior parietal planes

Figure 4

Illustration of sagittal and parasagittal USG examination, showing mid-sagittal and ventricular planes

Figure 5

Illustration demonstrating arterial and venous anatomy in mid sagittal plane

Figure 6(A-C)

Coronal USG at the level of frontal lobes (A), foramina of Monro (B), and trigone (C), demonstrating the interhemispheric fissure, lateral ventricles, and periventricular parenchyma

Figure 7(A-C)

Sagittal USG demonstrating corpus callosum, third and fourth ventricles, cerebellar vermis in midline (A). Cerebellum is relatively echogenic due to cerebellar foliae. Parasagittal images at the level of ventricle (B) and Sylvian region (C)

Figure 8

Coronal and parasagittal images of preterm (28 weeks) infant showing intracranial anatomy. Note the smooth surface of the immature brain. Distribution of the lobes colored

Figure 9(A-D)

Doppler images (A and B) demonstrating circle of Willis. Coronal USG demonstrating the vein of Galen. (C) Parasagittal study showing the small periventricular veins in the region of caudothalamic groove (D)

Figure 10(A, B)

Coronal USG demonstrating cavum septum (star) (A) and relation of vascular structures (B). Note that there are low-level echoes of cerebral gray and white matter, with subtle differences in the echoes of cortex and white matter. CSF spaces in Sylvian and inter-hemispherical region (arrows) are hyperechoic. Cerebellum is hyperechoic in relation to cerebral hemispheres

Figure 11(A, B)

(A) Sagittal USG demonstrating a relatively large massa intermedia (arrow) (B) Illustrates the relatively hyperechoic peritrigonal white matter(open arrow) in a normal neonate

Figure 12A

The figure demonstrates the location and the extent of the germinal matrix (colored pink)

Figure 12B

Diagrammatic representation of IVH classification by Papile (modified)

Figure 13

Coronal and sagittal sonographic images demonstrating a grade 1 hemorrhage at the caudothalamic groove

Figure 14

Coronal and both parasagittal images demonstrating the bilateral grade 3 hemorrhages with associated ventricular enlargement

Figure 15

Coronal and parasagittal images demonstrating bilateral grade 3 interventricular hemorrhage. Note the relatively hypoechoic areas around the hyperechoic clot, which indicates fresh, extensive bleed

Figure 16

Coronal examination demonstrating grade 4 right interventricular hemorrhage with extension to the adjacent parietal lobe. Note the right temporal horn showing blood products (open arrow)

Figure 17

Coronal and parasagittal images showing the extensive grade 4 hemorrhage with a large fresh hematoma in the periventricular parenchyma. Note the hemispherical mass effect and third ventricular deviation (open arrow)

Figure 18

USG images demonstrating a grade 4 left intracranial hemorrhage. Note extensive ill-defined intraparenchymal component with relatively less mass effect, indicating hemorrhagic venous infarct

Figure 19

Large right tempo-occipital and cerebellar hemorrhage, shown as the hyperechoic area in the coronal and parasagittal images

Figure 20(A, B)

Coronal USG demonstrating periventricular cystic changes (black arrow), sequelae of germinal matrix hemorrhage (A). Corresponding CT image shows tiny periventricular cystic lesions (B)

Figure 21

Coronal and parasagittal USG demonstrating a hyperechoic periventricular parenchyma (arrows)(grade 1 changes). There are also changes of mineralizing vasculopathy (open arrow)

Figure 22A

Coronal USG in a patient demonstrating hyperechoic periventricular parenchyma, sagittal image showing few early cystic changes (grade 2 changes)

Figure 22B

Cystic PVL changes in posterior frontal region shown by sagittal and coronal USG

Figure 23(A, B)

Coronal and parasagittal USG demonstrating focal cystic changes in the posterior frontal and the parieto-occipital periventricular region (A). Corresponding axial T1W image (B) demonstrating typical periventricular cystic changes in the peritrigonal region

Figure 24

Coronal USG at two levels demonstrating the subtle increase in the cerebral parenchymal echoes in a patient with acute ischemia (secondary to meconium aspiration). Note the small-capacity ventricles and obliterated cisternal spaces

Figure 25(A, B)

Acute ischemic changes demonstrated by coronal USG as the focal hyperechoic (open arrow) changes in the ganglionic areas (A). Corresponding axial non-contrast CT (B) showing the relative decrease in the density of ganglionic areas, a sign of acute ischemia

Figure 26

Coronal USG and the high-resolution parasagittal view demonstrating a large porencephalic cyst communicating with the left lateral ventricular cavity. The patient earlier had a large grade 4 hemorrhage

Figure 27(A, B)

Coronal illustration at the level of interventricular foramen, showing the measurements for bifrontal/ventricular ratio (A). USG in a patient with hydrocephalus showing measurement of ventricular/bifrontal ratio (B)

Figure 28

Coronal images at two levels showing hydrocephalus secondary to germinal matrix hemorrhage on the left side. Note the dilated third ventricle due to obstruction at the level of the aqueduct

Figure 29

Severe hydrocephalus due to congenital aqueductal stenosis. Sagittal image (C) showing a dilated third ventricle and completely collapsed fourth ventricle. Obstruction is at the level of aqueduct (arrow)

Figure 30(A, B)

(A, B) Coronal and sagittal USG demonstrating severe hydrocephalus in a patient with agenesis of the corpus callosum and midline interhemispheric cyst (open arrows)

Figure 31

Severe hydrocephalus mimicking hydrancephaly. There is a minimal residual cerebral mantle. Note the small posterior fossa

Figure 32

Axial examinations through the mastoid fontanelle showing a total obstruction at the level of the aqueduct. Dilated third ventricle is demonstrated by an open arrow. Incidentally Doppler flow is demonstrated in lateral sinus (long arrow)

Figure 33

Coronal and sagittal USG demonstrating large posterior fossa cyst in a case of Dandy-Walker syndrome. There is associated moderate hydrocephalus and agenesis of corpus callosum

Figure 34

Midline sagittal gray-scale and Doppler images demonstrating agenesis of corpus callosum. Anterior cerebral artery demonstrates vertical course (sunburst appearance). Note the radiating gyri in the frontal area, characteristic of agenesis of the corpus callosum

Figure 35

Coronal and parasagittal USG demonstrating colpocephaly in a patient with agenesis of corpus callosum. Also, there is hypoplasia of the cerebellum, mainly involving the right lobe

Figure 36(A, B)

(A and B) USG images in two different patients demonstrating dysplastic cerebral parenchyma with hyperechoic and cystic parenchymal changes. Note the gross widening of CSF spaces indicating loss of volume

Figure 37(A, B)

Large occipital meningocele with multiple layers of meninges and cystic cerebral parenchyma shown on USG (A). Coronal examination showing the dysplastic cystic changes in the brain (B)

Figure 38

Subtle calcification of the divisions of the middle cerebral artery, demonstrated as hyperechoic linear shadows in bilateral ganglionic regions. Patient also had slightly hyperechoic basal ganglia with small-capacity ventricles due to ischemia. Findings are consistent with the mineralizing vasculopathy

Figure 39

Parasagittal images demonstrating patchy areas of calcification in the branches of middle cerebral artery. Corresponding Doppler image showing patent vessels with wall calcification

Figure 40(A-D)

Gray-scale and Doppler coronal USG demonstrating a cystic midline structure in the region of posterior third ventricle with mass effect. (A) Typical swirl effect is noted on Doppler (B). Findings are highly suggestive of aneurysmal malformation of the vein of Galen. The corresponding axial and sagittal T2W images of MR examination confirming large aneurysmal dilatation of the vein of Galen (C and D)

Figure 41(A, B)

(A) High-resolution images of the subarachnoid spaces; normal high-convexity subarachnoid space is demonstrated (yellow arrows). (B) Shows a dilated subarachnoid space with internal echoes in a patient with pyogenic meningitis (black arrows)

Figure 42

USG images demonstrating incidental observation of a choroid plexus cyst(arrow) in the right lateral ventricle in a syndromic child