1. Dr. Vinayak Kodur 2nd year resident DM Neonatology
L.T.M.General Hospital,Sion
2. Introduction Was introduced in late 1970s Has become an
essential diagnostic tool in NICU The non-invasive nature of
ultrasonography makes it an ideal imaging technique in the neonate.
In the neonate and young infant, the fontanels and many sutures of
the skull are still open, and these can be used as acoustic windows
to look into the brain. Reliable tool for detecting congenital and
acquired anomalies of the peri-natal brain and the most frequently
occurring patterns of brain injury in both preterm and full-term
neonates.
3. When to scan All babies born at less than 32+6 weeks or with
birth weight of 1.5kg or below should be scanned. Scans may need to
be repeated more frequently, especially if the baby is particularly
unwell or if scans are abnormal. Babies of all gestations requiring
ventilation should have routine screening scans on a weekly basis
until extubation. The scan should also be repeated during the
discharge planning process.
4. Scan in Non-Ventilated and Ventilated Babies
5. Advantage of cranial US (CUS) Safe Bedside- compatible
Reliable Early imaging Serial imaging: Brain maturation Evolution
of lesions Inexpensive Suitable for screening
6. Aims of Neonatal CUS Exclude/demonstrate cerebral pathology
Assess timing of injury Assess neurological prognosis Help make
decisions on continuation of neonatal intensive care Optimise
treatment and support
7. Cranial Ultrasonography: Technical Aspects Transucers :
57.510 MHz Appropriately sized Standard examination: use 7.58 MHz
Tiny infant and/or superficial structures: use additional higher
frequency (10 MHz) Large infant, thick hair, and/or deep
structures: use additional lower frequency (5 MHz)
8. The acoustic windows : Anterior Fontanel The Standard view
window Posterior Fontanel Supplementary view window Mastoid
Fontanel Supplementary view window Temporal Supplementary view
window
9. Images are usually taken through the anterior fontanelle. In
the coronal plane, a series of images are taken through the frontal
lobes, more posteriorly through the ventricles and thalami, then
along the plane of the choroid plexus, then superior to that. The
sagittal images are initially taken in the midline, with images
then taken on both sides at the level of the lateral ventricles
then periventricular areas.
10. Standard Views(Anterior Fontanel) Coronal Views (at least 6
standard planes)
11. The standard coronal planes:
12. Coronal Section
13. First coronal plane (C1) at the level of the frontal
lobes
14. Second coronal plane (C2) at the level of the frontal horns
of the lateral ventricles
15. Second coronal plane (C2) at the level of the frontal horns
of the lateral ventricles The transducer is angled back. The CSF in
the lateral ventricles appears as a dark image. The lateral
ventricles are larger in preterm infants than in term infants.
Asymmetry between the lateral ventricles is common and is not
necessarily abnormal. The cavum septum pallucidum sits between the
lateral ventricles and is often large in preterm infants. The
corpus callosum appears above the cavum.
16. Third coronal plane (C3) at the level of the foramen of
Monro and the thirdventricle
17. Third coronal plane (C3) at the level of the foramen of
Monro and the thirdventricle With the transducer shifted slightly
further back, the third ventricle appears below both lateral
ventricles and the septum pallucidum. It is often small and
difficult to see, but can vary considerably in size. The foramen of
Monro (connecting lateral and 3rd ventricles) may be clearly seen.
The brainstem may be seen as a tree-like shape.
18. Fourth coronal plane (C4) at the level of the bodies of the
lateral ventricles.
19. Body of lateral ventricle Choroid plexus Thalamus
Hippocampal fissure Aqueduct of Sylvius Brain stem Parietal
lobe
20. Fifth coronal plane (C5) at the level of the trigone of the
lateral ventricles
21. Fifth coronal plane (C5) at the level of the trigone of the
lateral ventricles Angling further back cuts through the trigones
of the lateral ventricles. The choroid plexus fills the lateral
ventricles in this view and is prominent in preterm infants.
Choroid plexus haemorrhage may be difficult to differentiate from
bulky choroid. The white matter around the lateral ventricles may
appear quite echodense (bright) in this plane and is sometimes
called a "blush" or "flare".
22. Sixth coronal plane (C6) through the parieto-occipital
lobes
23. Sixth coronal plane (C6) through the parieto-occipital
lobes Angling the transducer even more results in an image that
slices above the lateral ventricles. In this plane, the occipital
cortex may be visualised.
24. Coronal View
25. Standard Views(Anterior Fontanel) Sagittal Views (at least
5 standard planes)
26. Parasagittal View
27. Midsagittal plane (S3) through the third and fourth
ventricles
28. Midline Sagittal This identifies useful landmarks. The
cerebellar vermis shows up as an echogenic image in the posterior
fossa. The 4th ventricle sits in front of this. The cisterna magna
sits below the cerebellar vermis and is not very echogenic. The
corpus callosum is seen sweeping from anterior to posterior with
the cingulate gyrus above and parallel to it. The parieto-occipital
sulcus is seen well above the posterior fossa.
29. Forth Ventricle Vermis of Cerebellum
30. Second and fourth parasagittal planes (S2, S4) through the
right and left lateral ventricles
31. Angled Parasagittal View: The shape of the lateral
ventricle is the key landmark for this view. The caudate nucleus
lies below the floor of the frontal horn of the lateral ventricle;
the thalamus lies behind and below it. The occipital horn of the
lateral ventricle is filled with choroid plexus. The choroid tucks
up in the caudothalamic groove in the floor of the lateral
ventricle and may be echogenic.
32. Para-saggital View
33. First and fifth parasagittal planes (S1, S5) through the
insulae (right and left)
34. Tangential Parasagittal View: Further angulation of the
transducer laterally results in a section lateral to the lateral
ventricles. The Sylvian fissure is the key landmark in this
view.
35. Saggital View
36. Preterm Vs Term Brain
37. Coronal View
38. Saggital View
39. ABNORMALITIES: PVL IVH Hydrocephalus
40. Peri Ventricular Leukomalacia (PVL) PVL is also known as
HIE of the preterm. A white matter disease that affects the
periventricular zones. In prematures this white matter zone is a
watershed zone between deep and superficial vessels. PVL presents
as areas of increased periventricular echogenicity PVL occurs most
commonly in premature infants born at less than 33 weeks gestation
(38% PVL) and less than 1500 g birth weight (45% PVL).
41. PVL Detection of PVL is important because a significant
percentage of surviving premature infants with PVL develop cerebral
palsy, intellectual impairment or visual disturbances.
42. Pathogenesis The pathogenesis of PVL has been found to
relate to three major factors: (1)the immature vasculature in the
periventricular watershed; (2)the absence of vascular
autoregulation in premature infants, particularly in the cerebral
white matter; and (3)the maturation-dependent vulnerability of the
oligodendroglial precursor cell damaged in PVL. These cells are
extremely vulnerable to attack by free radicals generated in the
ischemia-reperfusion sequence.
43. DeVries classification of PVL grading on ultrasound Grade I
PVL: Prolonged periventricular flare present for 7 days or more.
Grade II PVL: Presence of small-localized fronto-parietal cysts.
Grade III PVL: Extensive periventricular cystic lesion involving
occipital and fronto-parietal white matter. Grade IV PVL: Areas of
extensive sub cortical cystic lesions.
44. Flaring
45. Flaring The term flaring is used to describe the slightly
echogenic periventricular zones, that are seen in many premature
infants in the first week of life. During this first week it is not
sure if this is a normal variant or a sign of PVL grade 1. Flaring
persisting beyond the first week of life is by definition PVL grade
1. Follow up is needed to differentiate flaring from PVL grade
I.
46. Parasagittal image of a child with PVL grade 1
47. Grade 1 PVL PVL is diagnosed as grade 1 if there are areas
of increased periventricular echogenicity without any cyst
formation persisting for more than 7 days. Increased
periventricular echogenicity is however a nonspecific finding that
must be differentiated from the normal periventricular halo or
normal hyperechoic 'blush' posterosuperior to the ventricular
trigones. Suspect PVL if the echogenicity is asymmetric, coarse,
globular or more hyperechoic than the choroid plexus. The abnormal
periventricular echotexture of PVL usually disappears at 2-3
weeks.
48. Coronal and sagittal image of a child with PVL grade
2.
49. Grade 2 PVL The echogenicity resolves at the time of cyst
formation. 2% of the preterm neonates born before 32 weeks develop
cystic PVL. If cystic PVL is identified on cranial ultrasounds on
the first day of life, indicating that the adverse event was at
least 2 weeks prenatal rather than perinatal or postnatal.
51. Grade 3 PVL PVL is diagnosed as grade 3 if there are areas
of increased periventricular echogenicity, that develop into
extensive periventricular cysts in the occipital and
fronto-parietal region. For occipital lobe involvement sometimes
need a posterior fossa view.
52. Coronal and transverse images demonstrating PVL grade
4
53. Grade 4 PVL PVL is diagnosed as grade 4 if there are areas
of increased periventricular echogenicity in the deep white matter
developing into extensive subcortical cysts. PVL grade 4 is seen
mostly in fullterm neonates as opposed to PVL grade 1-3, which is a
disease of the preterm neonate.
54. Frontal and parieto-occipital Flare: Grade I PVL (sagittal
view)
59. IVH/GMH GRADING PAPILE By CT SCAN GRADE 1 - Isolated GMH
(no IVH) GRADE 2 - IVH without ventricular dilatation GRADE 3 - IVH
with ventricular dilatation GRADE 4 - IVH with parenchymal
hemorrhage
60. Germinal matrix hemorrhage (a/k/a periventricular
hemorrhage or preterm caudothalamic hemorrhage) These germinal
matrix hemorrhages occur in the highly vascular but also stress
sensitive germinal matrix, which is located in the caudothalamic
groove. This is the subependymal region between the caudate nucleus
and thalamus. The germinal matrix is matured by 34 weeks gestation,
such that hemorrhage becomes very unlikely after this age.
61. GMH... Most GMHs occur in the first week of life These
hemorrhages start in the caudothalamic groove and may extend into
the lateral ventricle and periventricular brain parenchyma. Grade 1
and 2 bleeds generally have a good prognosis. Grade 3 and 4 bleeds
have variable long-term deficits
62. Grade 1 IVH
63. Grade 2 IVH
64. Note the echogenic blood (arrowheads) filling 10 mm across
the atria of the posterior or anterior horn of lateral ventricles
at any point in the gestation alternatively, a separation of more
than 3 mm of the choroid plexus from the medial wall of the lateral
ventricle may be used
73. Fetal Hydrocephalus Asymmetric hydrocephalus when >2mm
discepancy between two sides. When ventriculomegaly is pronounced,
the choroid plexus will no longer lie in an almost parallel fashion
against the lateral ventricular wall. Tethered at the foramen of
Monro the free hanging choroid will "hang down" and appear to
"dangle" within the dilated ventricle. This appearance is often
termed the dangling choroid sign.
74. Severity The severity of ventriculomegaly can be further
classified as mild fetal ventriculomegaly: lateral ventricular
diameter between 10-12 mm moderate fetal ventriculomegaly: 12.1-15
mm severe fetal ventriculomegaly (also sometimes classified as
fetal hydrocephalus): lateral ventricular diameter >15 mm
75. Levene index
76. Levene index Up to 40 weeks of gestational age the
Levene-index should be used and after 40 weeks the ventricular
index. The Levene index is the absolute distance between the falx
and the lateral wall of the anterior horn in the coronal plane at
the level of the third ventricle. These measurements can be
compared to the reference curve and if it is >4mm than the 97th
percentile then said to be hydrocephalus.
77. Ventricular index
78. Ventricular index After 40 weeks the ventricular index or
frontal horn ratio should be used, i.e. the ratio of the distance
between the lateral sides of the ventricles and the biparietal
diameter.
79. Doppler Doppler Vascular Measurements: The vessels that are
the easiest to access are the anterior cerebral artery (ACA), best
seen through the anterior fontanelle in the sagittal plane and the
middle cerebral artery (MCA) best seen through the temporal window
in the axial plane. The Resistivity index (RI) : PS ED SV - DV PS
SV Where PS= peak systolic velocity and ED = end diastolic
velocity. The normal range is about 0.65 - 0.90. Values below 0.5
or above 0.9 are abnormal.
80. Choroid Plexus Cyst In postnatal US these cysts of the
chorioid plexus are often incidental findings without clinical
consequences. Chorioid plexus cysts (CPC) are however of importance
for obstetricians. At prenatal US these cysts can be predictive of
trisomy 18. About half of babies with Trisomy 18 show a CPC on
ultrasound, but nearly all of these babies will also have other
abnormalities on the ultrasound, especially in the heart, hand, and
feet. An exeption must be made for cysts that arise close to the
foramen of Monro.
81. CPC Although these cysts often disappear spontaneously,
follow up US is necessary to ensure disappearance. Some may produce
symptoms of raised intracranial pressure due to obstruction to the
cerebrospinal fluid (CSF) flow.
82. CPC
83. Grade 4 IVH with Porencephalic Cyst
84. Supplemental Acoustic Windows
85. Coronal view, using the posterior fontanel as an acoustic
window 8. Temporal Lobe 22. Cerebellum 23. Tentorium 25. Occipital
lobe 27. Calcarine fissure 29. Medulla Oblongata 36. Occipital horn
of lateral ventricle 38. Falx 39. Straight sinus (sinus
rectus)
86. Parasagittal view, using the posterior fontanel as an
acoustic window 8. Temporal Lobe 15. Choroid plexus 16. Thalamus
20. Parietal Lobe 21. Trigone of Lat. Ventri 22. Cerebellum 25.
Occipital lobe 27. Calcarine fissure
87. Upper Transverse view using the left temporal window
88. Lower transverse view using the left temporal window
89. Coronal view using the mastoid fontanel as an acoustic
window
90. Transverse view using the mastoid fontanel as an acoustic
window
91. Legends of Corresponding Numbers in Ultrasound Scans 23.
Tentorium 24. Mesencephalon 25. Occipital lobe 26.
Parieto-occipital fissure 27. Calcarine fissure 28. Pons 29.
Medulla oblongata 30. Fourth ventricle 31. Cisterna magna 32.
Cisterna quadrigemina 33. Interpeduncular fossa 34. Fornix 35.
Internal capsule 36. Occipital horn of lateral ventricle 37. Insula
38. Falx 39. Straight sinus (sinus rectus) 40. Temporal horn of
lateral ventricle 41. Circle of Willis 42. Prepontine cistern 1.
Interhemispheric fissure 2. Frontal lobe 3. Skull 4. Orbit 5.
Frontal horn of lateral ventricle 6. Caudate nucleus 7. Basal
ganglia 8. Temporal lobe 9. Sylvian fissure 10. Corpus callosum 11.
Cavum septum pellucidum 12. Third ventricle 13. Cingulate sulcus
14. Body of lateral ventricle 15. Choroid plexus (*: plexus in
third ventricle) 16. Thalamus 17. Hippocampal fissure 18. Aqueduct
of Sylvius 19. Brain stem 20. Parietal lobe 21. Trigone of lateral
ventricle 22. Cerebellum (a: hemispheres; b: vermis)