ن بطون } هات ك ال ت وهللا أخرجك م علمون شيئا أم

مع وا ة لعلك ألبصار واألفئ د وجعل لك الس

{تشكرون (78/سورة النحل)

Special thanks from the heart to

PROF. DR. MOHAMED ABDEL-ALEEM NAFADY

Professor of radiodiagnosis faculty of medicine, Al-Azhar university , Assuit

For his never end support during the conduction of this work

It is a great honor to work under his supervision.

PROF. DR. ABDEL-AZEZ GALAL ALDEN ALDARWESH

Professor of gynecology and obstetricsfaculty of medicine, Al-Azhar university , Assuit

For his never end support during the conduction of this work

It is a great honor to work under his supervision.

DR.SAAD REZK ABDEL WAHED

Assistant professor and head of radiodiagnosis departmentfaculty of medicine, Al-Azhar university , Assuit

For his guidance, support and perseverance.

Also , I would like to express my deepest thanks to

PROF. DR/ MUSTAFA THABET HUSSIN

Professor of radiodiagnosis Faculty of medicine , Assuit university

And

PROF. DR/ MOHAMAD ABDEL SAMIE MOHAMAD

Professor of gynecology and obstetricsFaculty of medicine , Al azhar university , Assuit.

For honoring us today to come , and for their effort in reviewing this study.

To my mother, my wife, my son

and my friends .

By

Dr. Tarek Mohamed M. Mansour

The brain is the only fetal organ that continuously develops & changes during fetal life

The largest changes occur within the 1st 20 wks, when most scans are done

CNS anomalies are among the most common fetal anomalies (second after cardiac anomalies).

To do fetal ultrasound neuroscan one has to:1. know some basic embryology2. Know the developmental milestones3. Have a high frequency transducer and understand

how 3D works4. Understand the most frequent CNS anomalies

Graphic shows the formation, closure of the neural tube. The neural plate (red) forms, folds, and fuses in the midline. The neural and cutaneous ectoderm then separate. Notochord (green), neural crest (blue) are shown.

A. Consists of 3 layers of cells: endoderm, mesoderm, and ectoderm.

B. Thickening of the ectoderm leads to the development of the neural plate

C. The neural groove begins to develop at 20 days.

D. At 22 days the neural groove closes along the length of the embryo forming the neural tube.

The neural tube closes in a bidirectional zipper-like manner, starting in the middle and proceeding toward both ends.

Development of primary vesicles is depicted. The prosencephalon (green) gives rise to the forebrain, the mesencephalon (purple) to the midbrain, and the rhombencephalon (light blue) to the hindbrain.

Embryonic brain at 22 weeks is mostly agyric with shallow sylvian fissures . Prosencephalon (green), metencephalon (yellow), and myelencephalon (light blue) are shown. Mesencephalic, midbrainstructures are not visible.

With advancing gestational age, multiple secondary and tertiary gyri develop, and the number and complexity of the cerebellar folia increase.

Three orthogonal images and thick slice of three-dimensional reconstructed image (lower right) of normal brain at the end of 8 weeks of gestation. The development of premature ventricular system is seen.

Donald School Textbook of Ultrasound inObstetrics and Gynecology (third edition 2011).

Three-dimensional (3D) sonography should be accepted as a natural development of ultrasound imaging technology.

Fast computer processing is essential for 3D and 4D sonography.

The first 3D-capable systems were developed in the mid-1990s.

3D acquisition was performed by moving the transducer over the region of interest (ROI) with the operator’s hand at a constant speed.

On reaching the ROI, the operator must keep the transducer stable while the patient stays still, so that the probe may continue scan.

Images are then captured and processed by a computer that will display them three-dimensionally.

In the multiplanar volume mode three planes are shown – longitudinal or sagittal (A-plane), transverse (B-plane), and coronal (C-plane) – and an orthogonal reconstruction is obtained, which may be rotated around three axes (x, y, z)

1- Maternal factors:

Abdominal wall thickness.

Colitis.

Mother breathing.

Obesity.

3- Amniotic fluid (oligohydramnios).

2- Fetal factors:

Position (face down).

Age of fetus.

Movement of the fetus.

Multiple fetuses.

4- Operator skills and experience.

5- Machine capabilities.

The most useful features of 3D scanning of the fetal CNS:

– Orthogonal planes

–Tomographic imaging

–Angiography

– Inversion mode.

–Thick slice/volume contrast imaging

3D multiplanar image analysis (normal brain at 18 weeks of gestation). The use of three orthogonal views is helpful in obtaining the orientation of the brain structure. Coronal (A), sagittal (B), and axial (C) images can be visualized on a single screen. Any rotation of the brain image around any (x,y,z) axis is possible

Tomographic ultrasound imaging (TUI) of the fetal brain. Normal brain in coronal section at 31 weeks of gestation. Intracranial structures, including gyral formation, are clearly demonstrated and also compare both cerebral hemisphere

Normal brain at 9 weeks of gestation. Tomographic ultrasound imaging of sagittal (A), coronal (B), and axial (C) sections. The premature ventricular system is demonstrated. In the coronal and axial sections, the already-divided bilateral hemispheres can be visualized

Normal brain at 12 weeks and 5 days of gestation. Tomographic ultrasound imaging of sagittal (A), coronal (B), and axial (C) sections. The rate of occupation of the cerebral hemispheres becomes larger compared with previous images. The bilateral echogenic structure is the choroid plexus filled the lateral ventricles

Normal brain at 17 weeks of gestation. Tomographic ultrasound imaging of sagittal (A), coronal (B), and axial (C) sections. The choroid plexus (echogenic part) shifts to the posterior half of the lateral ventricles

Normal brain at 31 weeks of gestation. Tomographic ultrasound imaging of sagittal (A), coronal (B), and axial (C) sections. Formation of sulci and gyri is clearly observed from around 30 weeks of gestation. The Sylvian fissure (arrows) is formed as the lateral sulcus

Sonography of the CNS

Basic examination

Axial plane Sagittal plane

Neuroscan or extended examination

a: Transventricular

b: Transthalamic

C: Transcerebellar

A: The Mid sagittal Plan b: Para sagittal plane

Biometry:

Biparietal diameter.

Head circumference.

Occipito-frontal diameter.

Atrium of lateral ventricle at the level of choroid plexus.

Transcerebellar diameter.

Depth of cisterna magna

The brain structures:

Head shape.

Lateral ventricles.

Cavum septi pellucidum.

Thalami.

Cerebellum.

Cisterna magna.

Spine.

The brain structures:

Anterior horns

Posterior horns

3rd and 4th ventricle

Intraventricular foramina

Cavum septi pellucidi

Corpus callosum

Pericallosal artery

Caudate nuclei

Thalami

Cerebellum & vermis

Cisterna magna

Interhemispheric fissure

Fissures

Sphenoidal bone

Ocular orbits

Better demonstration of the midline structures esp. corpus callosum and cerebellar vermis.

Visualization of both hemispheres.

Better identification of cerebral sulci.

Detailed examination of fetal spine.

Anencephaly.

Hydrocephalus.

Cephalocele.

Iniencephaly.

Arnold-Chiarii II malformation.

Dandy walker malformation.

Corpus callosum agenesis.

Holoprosencephaly.

Hydrancephaly.

Porencephaly.

Arachnoid cyst.

Choroid plexus cyst.

Lissencephaly.

Vein of Galen aneurysm.

1/1000, M:F = 4:1

Anencephaly/exencephaly sequences.

Absent cranial vault.

Begins as exencephaly (exposed neural tissue) that gets eroded by amniotic fluid and fetal movement.

1st trimester: exposed brain tissue gives Mickey Mouse appearance.

2nd & 3rd trimester: neural tissue has resolved (frog like appearance).

The three orthogonal planes and a rendered three-dimensional image of the fetus seen in The coronal image (C) demonstrates lack of calvarial bon

A typical-appearing fetus with exencephaly-anencephaly sequence is shown using the tomographic feature. there is less visible brain tissue.

Excess CSF production or obstructed flow.

Measures the posterior horn of lateral ventricle > 10 mm in 2nd trimester.

Choroid plexus to medial border of lateral ventricle wall > 3 mm.

Maximum cortical thickness < 1o mm. denoting poor prognosis.

Aqua ductal stenosis lead to third ventricle dilatation.

Time of delivery: when doppler shows increase MCA PI which mean increase intracranial tension.

Hydrocephalus (left) and ventriculomegaly (right). Tomographic ultrasound imaging of X-linked hydrocephalus at 21 weeks and ventriculomegaly at 25 weeks .

Herniation of

1. Meninges = meningocele.

2. Meninges + brain tissue = cephalocele.

75% occipital defect.

40% neonatal death.

Survivors 80% neurological impairment.

Extensive ONTD triad of:1. Occipital encephalocele.2. Fixed hyperextension of the fetal head.3. Cervical dysraphism.

US findings:1. Short CRL due to absent cervical spine.2. Head fixed in hyperextension.3. Cephalocele.

3/10,000 F:M 9:1 Lethal condition.

Spina bifida, ONTD, spinal dysraphism.

US findings:

1. Obliterated cisterna magna.

2. Banana sign (cerebellum raped around brain stem 90%).

3. Lemon sign (depressed frontal bone 98%).

4. Ventriculomegaly.

5. Lumbo-sacral myelo-meningocele.

High morbidity.

Dysgenesis of the cerebellar vermis.

Dilated 4th ventricle connected with cisterna magna.

Mortality

1. 50% when isolated.

2. 80% when associated with other anomaly.

Karyotyping: 30% chromosomal.

1:30 000

Low intelligence is 80% of isolated cases.

1: 20, 000

US findings:

1. Absent cavum septum pellucidum in axial planes.

2. Lateralization of lateral ventricles.

3. Tear drop shape.

4. Mild ventriculomegaly.

Mid sagittal plane is diagnostic.

85% isolated.

Ventriculomegaly in a case of complete agenesis of the corpus callosum (frontal horns scalloped outward)

Sever brain and facial malformations.

Incomplete cleavage of prosencephalon at 4-6 W.

1:16,000.

Three forms:

1. Alobar: single ventricle & fused thalami.

2. Semi lobar: Partially separated hemispheres & partially fused thalami.

3. Lobar: separated hemispheres& thalami with absent CSP.

Prognosis:

1. Alobar: incompatible with life.

2. Semi lobar and lobar: mental retardation

Alobar holoprosencephaly at 15 weeks of gestation. (A–C) Three orthogonal images of intracranial structure showing a complete single ventricle within a single-spheredcerebral structure

Complete destruction of cerebral hemispheres with normal cerebellum and brain stem.

May be due to vascular occlusion or toxoplasmosis.

Lethal.

US findings:

1. No cerebral tissue (No MCA flow).

2. Falx cerebri may be seen.

3. Normal posterior fossa.

4. Brain stem protrude to fluid filled calvaria.

Hydranencephaly. The absence of brain high in the convexities distinguishes hydranencephaly from severe hydrocephaly. The midbrain and posterior fossa (arrows) are normal

Arachnoid cyst is encysted CSF displaced normal brain tissue of good prognosis if isolated.

Thank you

Thank you