Table Of Content[Teresa Margarida da Fonseca Alves Loureiro]
DESCRIÇÃO DA ANATOMIA DO CÉREBRO FETAL
NORMAL E ANÓMALO POR ECOGRAFIA
TRIDIMENSIONAL NO PRIMEIRO TRIMESTRE DA
GRAVIDEZ
DESCRIPTIVE ANATOMY OF THE NORMAL AND
ABNORMAL FETAL BRAIN BY THREE-DIMENSIONAL
ULTRASOUND IN THE FIRST TRIMESTER OF PREGNANCY
DISSERTAÇÃO DE DOUTORAMENTO EM MEDICINA
PHD THESIS
2012
Dissertação de candidatura ao grau de
Doutor em Medicina, na área de Obstetrícia,
submetida à Faculdade de Medicina
da Universidade do Porto
Orientador: Prof. Doutor Nuno Montenegro
Co-orientador: Prof. Doutor Kypros Nicolaides
Júri:
Prof. Doutor José Agostinho Marques Lopes
Prof.ª Doutora Francisca Sonia Molina Garcia
Prof. Doutor Luís Mendes Graça
Prof.ª Doutora Maria Amélia Duarte Ferreira
Prof. Doutor João Francisco Montenegro de Andrade Lima Bernardes
Prof. Doutor Nuno Aires Mota de Mendonça Montenegro
Prof.ª Doutora Alexandra Matias Pereira da Cunha Coelho de Macedo
Os estudos sobre os quais se desenvolveu esta tese foram realizados no Serviço de Obstetrícia e
Ginecologia do Centro Hospitalar de S. João, Porto, Portugal; no Harris Birthright Research Centre for
Fetal Medicine, King’s College Hospital Medical School, Londres, Reino Unido e Screening Unit,
University College Hospital, Londres, Reino Unido.
The studies presented in this thesis were performed at the Department of Obstetrics and Gynecology,
S. João Hospital, Medical School, University of Porto, Porto, Portugal; Harris Birthright Research
Centre for Fetal Medicine, King’s College Hospital and Screening Unit, University College Hospital,
London, UK.
CONTENTS
Abbreviations .......................................................................................................... 7
Summary ................................................................................................................ 13
PORTUGUESE LANGUAGE .................................................................................. 14
ENGLISH LANGUAGE ........................................................................................... 18
Chapter 1
BACKGROUND ...................................................................................................... 21
Abstract ................................................................................................................... 22
1.1. General value of ultrasound in prenatal diagnosis and screening
of fetal abnormalities ....................................................................................... 23
1.2. Evolution of ultrasound examination from the second to the first trimester ..... 26
1.3. Neurosonography: from the second to the first trimester .................................. 28
1.4. Application of three-dimensional ultrasound in fetal brain assessment ............ 29
1.5. Three-dimensional ultrasound methodology in assessing first trimester
fetal brain ......................................................................................................... 30
1.6. The normal brain - the ventricular system and cerebrospinal fluid ................... 31
1.7. Open spina bífida ............................................................................................. 33
1.7.1. Etiology .................................................................................................. 34
1.7.2. Chiari type II malformation ..................................................................... 35
1.7.3. Prognosis ............................................................................................... 36
1.7.4. Second trimester screening and diagnostic tests for open
neural tube defects ................................................................................ 37
Serum AFP followed by amniocentesis for acetylcholinesterase .......... 37
Ultrasound scan as both screening and diagnostic test ........................ 38
1.7.5. First trimester screening for open neural tube defects ........................... 40
The mid-sagittal view and intracranial translucency (IT) ....................... 40
1.8. Posterior fossa abnormalities ........................................................................... 43
1.8.1. Embryology of the posterior fossa .......................................................... 43
1.8.2. Dandy-Walker malformation ................................................................... 44
Terminology – the Dandy-Walker spectrum/complex ............................ 45
Dandy-walker malformation and aneuploidy and other brain
abnormalities. ........................................................................................ 46
Prognosis .............................................................................................. 46
Inconsistencies in Dandy-Walker malformation diagnosis .................... 47
1.8.3. Prenatal ultrasound evaluation of the fourth ventricle ............................ 48
The meaning of an isolated enlarged fourth ventricle ............................ 48
The fourth ventricle and aneuploidies ................................................... 49
1.9. Ventriculomegaly .............................................................................................. 49
1.9.1. Definition and incidence ......................................................................... 49
1.9.2. Etiology .................................................................................................. 50
1.9.3. Prognosis ............................................................................................... 51
1.9.4. First trimester assessment of lateral ventricles ...................................... 52
Chapter 2
AIM AND OUTLINE OF THE THESIS .................................................................... 69
2.1. Introduction ...................................................................................................... 71
2.2. Aim and outline of the thesis ............................................................................ 72
Chapter 3
CEREBRAL VENTRICULAR SYSTEM IN NORMAL FETUSES
AT 11-13 WEEKS’ GESTATION ............................................................................ 75
Chapter 4
CEREBRAL VENTRICULAR SYSTEM IN FETUSES WITH OPEN SPINA BIFIDA
AT 11-13 WEEKS’ GESTATION ............................................................................ 91
Chapter 5
DILATED FOURTH VENTRICLE IN FETUSES WITH TRISOMY 18,
TRISOMY 13 AND TRIPLOIDY AT 11-13 WEEKS’ GESTATION ....................... 107
Chapter 6
LATERAL VENTRICLES IN ANEUPLOIDIES AT 11-13 WEEKS’ GESTATION ........ 119
Chapter 7
GENERAL DISCUSSION / MAIN CONCLUSIONS .............................................. 133
List of publications ............................................................................................. 141
Acknowledgements / Agradecimentos.............................................................. 145
[Abbreviations]
ABBREVIATIONS
2D US Two-dimensional ultrasound
3D US Three-dimensional ultrasound
3V Third ventricle
4V Fourth ventricle
A Aqueduct of Sylvius
ACC Agenesis of the corpus callosum
AChE acetylcholinesterase
AFP Alphafetoprotein
AMA Anterior membranous area
BPD Biparietal diameter
BS Brainstem
BSOB Brain stem to occipital bone diameter
CLR Choroid plexus area to lateral ventricle area ratio
CM Cisterna magna
CM II Chiari malformation II
CNS Central nervous system
CRL Crown-rump length
CSF Cerebrospinal fluid
DWM Dandy-Walker malformation
DWV Dandy-Walker variant
eCSF Embryonic cerebrospinal fluid
GA Gestational age
HW Hemispheric width
IT Intracranial translucency
LOA Limits of agreement
LV Lateral ventricle
LVW Lateral ventricle width
MMC Myelomeningocele
N Number of cases
NT Nuchal translucency
NTD Neural tube defects
PMA Posterior membranous area
Sens Sensitivity
Spec Specificity
TA Transabdominal scan
TV Transvaginal scan
US Ultrasound scan
VM Ventriculomegaly
ANATOMY OF THE FETAL BRAIN BY 3D ULTRASOUND IN THE 1ST TRIMESTER 7
PhD THESIS [Teresa Loureiro] 2012
Description:PhD THESIS [Teresa Loureiro] 2012. 25. Table I: Validity of US as diagnostic tool in a routine setting by author and year of publication. GA= gestational age; NR = not reported. Ultrasound has also a well recognized clinical role as a screening test. (Nicolaides KH, 2004, 2011). The identification
