Ebook Donald school textbook of ultrasound in obstetrics and gynecology (3rd edition): Part 1

Donald School
Textbook of Ultrasound in
Obstetrics and Gynecology


Donald School
Textbook of Ultrasound in
Obstetrics and Gynecology
THIRD EDITION

Editors

Asim Kurjak

MD PhD

Professor and Chairman
Department of Obstetrics and Gynecology
Medical School University of Zagreb
Sveti Duh Hospital
Zagreb, Croatia

Frank A Chervenak

MD PhD

Professor and Chairman
Department of Obstetrics and Gynecology
The New York Weill Hospital-Cornell Medical Center
New York, USA

®

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Donald School Textbook of Ultrasound in Obstetrics and Gynecology

© 2011, Jaypee Brothers Medical Publishers
All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in
any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written
permission of the editors and the publisher.
This book has been published in good faith that the material provided by contributors is original. Every effort is
made to ensure accuracy of material, but the publisher, printer and editors will not be held responsible for any
inadvertent error(s). In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only.
First Edition: 2004
Second Edition: 2008
Third Edition: 2011
ISBN 978-93-5025-259-8
Typeset at JPBMP typesetting unit
Printed in India


To
Ian Donald
(Our Teacher and Friend)


CONTRIBUTORS
Badreldeen Ahmed
Head
Feto-Maternal Unit
Department of Obstetrics and
Gynecology
Women’s Hospital
Hamad Medical Corporation
Doha, State of Qatar

María J Barco
Gynecologic Centre “Bolonia”
Zaragoza, Spain

Romina Castagno
Hospital Vall d´ Hebron
Barcelona, Spain

Jill Beithon
Ultrasound Services Sanford
Health
Fargo, ND, USA

Gabriele Centini
Prenatal Diagnosis Unit
University of Siena
Siena, Italy

Juan Luis Alcázar
Department of Obstetrics and
Gynecology
University Clinic of Navarra
School of Medicine
University of Navarra
Pamplona, Spain

Isaac Blickstein
Department of Obstetrics and
Gynecology
Kaplan Medical Center

Rehovot, and
Hadassah-Hebrew University
School of Medicine
Jerusalem, Israel

Giovanni Centini
Prenatal Diagnosis Unit
University of Siena
Siena, Italy

Tatjana Bozanovic
School of Medicine
Belgrade University, and
Institute for Obstetrics and
Gynecology
Clinical Center of Serbia
Belgrade, Serbia

Stephen T Chasen
Weill Medical College of Cornell
University, New York, USA

Cristian Andrei
Department of Obstetrics and
Gynecology
Elias University Hospital
Carol Davila University of
Medicine
Bucharest, Romania
Aris Antsaklis

Head
1st Department of Obstetrics and
Gynaecology
“Alexandra” Maternity Hospital
University of Athens
Medical School
Athens, Greece

Lluis Cabero
Department of Obstetrics and
Gynecology
Hospital Vall d'Hebron
Barcelona
Spain

Guillermo Azumendi Pérez
Clinica Gutenberg
Malaga, Spain

José M Carrera
Senior Member
Department of Obstetric and
Gynaecology
University Institute Dexeus
Autonomous University of
Barcelona
Barcelona, Spain

Kazunori Baba
Center for Maternal, Fetal and

Neonatal Medicine
Saitama Medical Center, Saitama
Medical University
Saitama, Japan

Elena Carreras
Fetal Medicine Unit
Obstetrics and Gynecology
Department
Hospital Vall d’Hebron
Barcelona, Spain

Silvia Arevalo
Fetal Medicine Unit
Hospital Vall d’Hebron
Barcelona, Spain

Aleksandar Cetkovic
Clinical Center of Serbia
Belgrade, Serbia

Frank A Chervenak
Chairman
Department of Obstetrics and
Gynecology
Joan and Sanford I Weill Medical
College of Cornell University
The New York Presbyterian
Hospital, New York, USA
Judith L Chervenak

New York University School of
Medicine
New York, USA
Carmina Comas Gabriel
Fetal Medicine Unit
Department of Obstetrics and
Gynecology
University Institute Dexeus
Barcelona, Spain
Antonella Cromi
Department of Obstetrics and
Gynecology
University Medical School of
Insubria, Varese, Italy


viii

Donald School Textbook of Ultrasound in Obstetrics and Gynecology

Vincenzo D’Addario
Department of Obstetrics and
Gynecology, University of Bari
Bari, Italy
Luca Di Cagno
Fetal Medicine Unit
Department of Obstetrics and
Gynecology, University of Bari
Bari, Italy
Edoardo Di Naro

III Obstetrics and Gynecology Unit
University Medical School of Bari
Bari, Italy
Marko Dosen
Department of Reproductive
Medicine and Gynecologic
Endocrinology
University Clinical Center Maribor
Maribor, Slovenia
Alaa Ebrashy
Director
Fetal Medicine Unit
Kasr El Aini Hospital
Faculty of Medicine
Cairo University
Cairo, Egypt
A Kubilay Ertan
Head
Department of Obstetrics and
Gynecology
Hospital of Leverkusen
Leverkusen,
Germany
Francesc Figueras
Service of Fetal Medicine
Clinical Institute of Gynecology
Obstetrics and Neonatology
University of Barcelona
Barcelona,
Spain

Biserka Funduk Kurjak
Department of Obstetrics and
Gynecology
Medical School
University of Zagreb
Zagreb, Croatia

Alessandra Giocolano
Department of Obstetrics and
Gynecology
III Obstetrics and Gynecology Unit
University Medical School of Bari
Bari, Italy
Teresa Higueras
Fetal Medicine Unit
Hospital Vall d'Hebron
Barcelona
Spain
Ulrich Honemeyer
Head
Department of Obstetrics and
Gynecology
Welcare Hospital
Dubai, UAE
Jon Hyett
Head
High Risk Obstetrics
RPA Women and Babies
Royal Prince Alfred Hospital
Central Clinical School

University of Sydney
Sydney, Australia
Shigenori Iwagaki
Department of Maternal and Fetal
Medicine
National Hospital Organization
Nagara Medical Center
Nagara Gifu, Japan
Robin B Kalish
Division of Maternal-Fetal Medicine
Department of Obstetrics and
Gynecology
Weill Medical College of Cornell
University, New York, USA
Ichiro Kawabata
Department of Maternal and Fetal
Medicine
National Hospital Organization
Nagara Medical Center
Nagara Gifu, Japan
Ashok Khurana
The Ultrasound Lab
New Delhi, India

Sanja Kupesic Plavsic
Department of Medical Education
Paul L Foster School of Medicine
Texas Tech University
El Paso, Texas, USA
Asim Kurjak

Department of Obstetrics and
Gynecology
Medical School
University of Zagreb
Zagreb, Croatia
Mario Lituania
Centro di Fisiopatologia
Preconcezionale e Prenatale.
Ospedali Galliera Genova
Genova, Italy
Aleksandar Ljubic
School of Medicine
University of Belgrade, and
Institute for Obstetrics and
Gynecology
Clinical Center of Serbia
Belgrade, Serbia
Kazuo Maeda
Department of Obstetrics and
Gynecology (Professor Emeritus)
Tottori University Medical School
Yonago, Japan
Jaideep Malhotra
Malhotra Nursing and Maternity
Home (P) Ltd
Agra, India
Narendra Malhotra
Malhotra Nursing and Maternity
Home (P) Ltd
Agra, India

Neharika Malhotra
Malhotra Nursing and Maternity
Home (P) Ltd
Agra, India
Alexandra Matias
Department of Obstetrics and
Gynecology
Porto Medical Faculty of Medicine
Hospital of S João
Porto, Portugal


Contributors
Eva Meler
Department of Obstetrics and
Gynaecology
University Institute Dexeus
Autonomus University of
Barcelona, Barcelona, Spain
Luis T Mercé
CENEGO (National Center of
Gynecology and Obstetrics US)
and Assisted Reproduction Unit
International Ruber Hospital
Madrid, Spain
Eberhard Merz
Chairman
Department of Obstetrics and
Gynecology
Krankenhaus Nordwest

Frankfurt/Main, Germany
Srboljub Milicevic
Institute for Obstetrics and
Gynecology
Clinical Center of Serbia
Belgrade, Serbia
Berivoj Miskovic
Head
Department of Obstetrics and
Gynecology
Clinical Hospital Sveti Duh
Zagreb, Croatia
Giovanni Monni
Head
Department of Obstetrics and
Gynecology
Prenatal and Preimplantation
Genetic Diagnosis
Microcitemico Hospital
Cagliari, Sardinia, Italy
Nuno Montenegro
Porto Medical Faculty of Medicine
Department of Obstetrics and
Gynecology, Hospital of S João
Porto, Portugal
Ajlana Mulic-Lutvica
Department of Women’s and
Children’s Health
Obstetrics and Gynaecology
Uppsala University

Uppsala, Sweden

Zehra Nese Kavak
Director
Fetal Medicine Unit
Department of Obstetrics and
Gynecology
Marmara University Teaching and
Research Hospital, Pendik
Istanbul, Turkey
Agnieszka Nocun
Gynecology and Oncology Clinic
University Hospital in Krakow
Krakow, Poland
Aleksandra Novakov
School of Medicine
University of Novi Sad
Clinical Center of Vojvodina
Novi Sad, Serbia
Zoltán Papp
Maternity Private Clinic
Semmelweis University
Budapest, Hungary
George A Partsinevelos
1st Department of Obstetrics and
Gynaecology
University of Athens
Medical School
Athens, Greece
Bhargavi Patham

Department of Medical Education
Paul L Foster School of Medicine
Texas Tech University
El Paso, Texas, USA
Vincenzo Pinto
Department of Obstetrics and
Gynecology
University of Bari
Bari, Italy

ix

Ritsuko K Pooh
Director
CRIFM Clinical Research Institute
of Fetal Medicine PMC
Osaka, Japan
KyongHon Pooh
Department of Neurosurgery
Kagawa National Children’s
Hospital, Zentsuji,
Japan
Maja Predojevic
Department of Physiology
Medical School
University of Zagreb
Zagreb, Croatia
Luigi Raio
Department of Obstetrics and
Gynecology, University of Bern

Bern, Switzerland
Jai Prakash Rao
Malhotra Nursing and Maternity
Home (P) Ltd
Agra, India
Frederico Rocha
Division of Maternal Fetal
Medicine
Department of OB/GYN and
Women’s Health
John A Burns School of Medicine
University of Hawaii
Honolulu, Hawaii,
USA
Carlota Rodó
Fetal Medicine Unit
Hospital Vall d'Hebron
Barcelona, Spain

Armando Pintucci
Department of Obstetrics and
Gynecology
University of Bari
Bari, Italy

Lucia Rosignoli
Prenatal Diagnosis Unit
P Palagi Hospital
Florence, Italy

Branko M Plavsic
Department of Radiology
Paul L Foster School of Medicine
Texas Tech University
El Paso, Texas, USA

Cristina A Rossi
Fetal Medicine Unit
Department of Obstetrics and
Gynecology, University of Bari
Bari, Italy


x

Donald School Textbook of Ultrasound in Obstetrics and Gynecology

Aida Salihagic Kadic
Department of Physiology, and
Croatian Institute for Brain
Research Medical School
University of Zagreb
Zagreb, Croatia
Cihat en
Chairman
Department of Perinatology
Cerrahpasa Medical School
University of Istanbul
Istanbul, Turkey
Geeta Sharma

Weill Medical College of Cornell
University
New York, USA
Kohei Shiota
Department of Anatomy and
Developmental Biology and
Congenital Anomaly Research
Center
Kyoto University Graduate School
of Medicine
Kyoto, Japan
Daniel W Skupski
Director
Maternal-Fetal Medicine
Associate Chairman
Department of Obstetrics and
Gynecology
The New York Hospital of Queens
Flushing, New York, USA
Jiri Sonek
Department of Obstetrics and
Gynecology
Wright State University
President
Fetal Medicine Foundation of
the United States of America
Dayton, Ohio, USA
Yuichiro Takahashi
Department of Maternal and Fetal
Medicine

National Hospital Organization
Nagara Medical Center
Nagara Gifu, Japan

András Tankó
Department of Obstetrics and
Gynecology
County Hospital
Kecskemét, Hungary
H Alper Tanriverdi
Head
Maternal-Fetal Medicine Unit
Department of Obstetrics and
Gynecology
Adnan Menderes University
Faculty of Medicine
Aydin, Turkey
Sakshi Tomar
Malhotra Nursing and Maternity
Home (P) Ltd
Agra, India
Nuria Toran
Department of Pediatric Pathology
Hospital Vall d'Hebron
Barcelona
Spain
Zoltán Tóth
Department of Obstetrics and
Gynecology
Debrecen University

Debrecen, Hungary
Boris Ujevic
Department of Obstetrics and
Gynecology
Clinical Hospital Sveti Duh
Zagreb, Croatia
Martina Ujevic
Polyclinic “Vili”
Zagreb, Croatia
Gino Varga
Polyclinic “Nemetova”
Zagreb, Croatia
Oliver Vasilj
Department of Obstetrics and
Gynecology
Clinical Hospital Sveti Duh
Zagreb, Croatia

Radu Vladareanu
Chairman
Department of Obstetrics and
Gynecology
Elias University Hospital
Carol Davila University of
Medicine
Bucharest, Romania
Veljko Vlaisavljevic
Department of Reproductive
Medicine and Gynecologic
Endocrinology

University Clinical Center Maribor
Maribor, Slovenia
Marcin Wiechec
Obstetrics and Perinatology Clinic
University Hospital in Krakow
Krakow, Poland
Tevfik Yoldemir
Department of Obstetrics and
Gynecology
Marmara University Teaching and
Research Hospital, Pendik
Istanbul, Turkey
Nadah B Zafar
Department of Medical Education
Paul L Foster School of Medicine
Texas Tech University
El Paso, Texas, USA
Ivica Zalud
Chief,
Division of Maternal Fetal
Medicine
Department of OB/GYN and
Women’s Health
John A Burns School of Medicine
University of Hawaii
Honolulu, Hawaii, USA
Mona Zvanca
Department of Obstetrics and
Gynecology
Elias University Hospital

Carol Davila University of
Medicine
Bucharest, Romania


PREFACE TO THE THIRD EDITION
The Ian Donald International School of Ultrasound bears testament to globalization in its most successful and
worthwhile form. The school was founded in Dubrovnik in 1981; in the preface of the first edition in 2004 we were
proud to announce that the School had grown to 8 branches. Since then, the growth has been meteoric and now
consists of 55 branches in almost every corner of the globe. The reason for this success has been the tireless and
selfless efforts of the world’s leading authorities in ultrasound who are willing to dedicate their valuable time
without reimbursement to teach sonologists and sonographers throughout the world. Our teachers put national,
religious, political, and other parochial considerations aside as they strive to improve the care of all women
and fetal patients. Politicians in the countries represented by our School have much to learn from the purity of
spirit that exists throughout our international family. We believe that Ian Donald is smiling down from heaven at
the School that bears his name.
In the educational efforts of the 55 branches of the Ian Donald School, there is clearly a need for a textbook to
complement and supplement lectures and didactic sessions. The first and second textbooks were successful in this
endeavor, but with the explosion of knowledge, it was clear that an expanded and updated third edition would
be invaluable. For the sake of simplicity, our book is divided into three sections. Section One deals with a variety
of topics that lay the foundation for the rest of the book. Section Two addresses the myriad subtopics in obstetric
ultrasound that optimize the care of pregnant women and fetal patients. The last section addresses the essential
role that ultrasound plays in the many dimensions of clinical gynecology.
A special word of thanks to Jadranka, our tireless secretary for her hundreds of dedicated hours of quality
work.
We are grateful to many course directors and lecturers of the Ian Donald School who have enabled its growth
and have selflessly contributed to this volume. In order to maximize the reach of this textbook by minimizing its
price, all contributors have waived any honorarium or royalty. Their dedication to the dream of globalized quality
ultrasound has enabled its reality.
Asim Kurjak

Frank A Chervenak


PREFACE TO THE FIRST EDITION
Ultrasound is the backbone of modern obstetric and gynecology practice. For those of us old enough to remember
the dark ages of clinical practice prior to ultrasound, this is not an overstatement. Younger physicians may find it
hard to imagine the clinical realities of doctors who delivered undiagnosed twins presenting at delivery, who
performed unnecessary surgeries for the clinical suspicion of a pelvic mass that was not present, and who consoled
anguished parents when an anomalous infant was born unexpectedly. Recent technological breakthroughs in
diagnostic ultrasound, including the advent of color Doppler, power Doppler, three-dimensional and fourdimensional imaging, have led ultrasound to surpass the expectations of Ian Donald, its visionary father.
The Ian Donald School was founded in 1981 and is devoted to international education and research cooperation
concerning all aspects of diagnostic ultrasound. The first chapter was founded in Dubrovnik at that time and has
now expanded to 7 additional national branches.
To facilitate the educational efforts of the Ian Donald School we believed a textbook would be of value. The
text is divided into three parts general aspects, obstetrics, and gynecology. All contributors are either present or
former teachers in the 8 branches of the Ian Donald School. We believe this comprehensive text with state-of-theart images will be of value for both new learners and experienced practitioners.
We are grateful to all of the teachers in the School and especially to all of the contributors to this textbook for
their tireless efforts to enhance the quality of ultrasound practice throughout the world.

Asim Kurjak
Frank A Chervenak


CONTENTS
SECTION 1: GENERAL ASPECTS
1. Safety of Ultrasound in Obstetrics and
Gynecology ................................................................ 3
Kazuo Maeda
• Introduction 3
• Diagnostic Ultrasound Instruments and

Ultrasound Intensity 3
• Ultrasound Intensity of Doppler
Ultrasound 4
• The Effect of Heating on Mammal
Fetuses 4
• Non-hazardous Exposure Time of
the Fetus to the Heat 4
• Strategy for the Safety of Diagnostic
Ultrasound Equipments 5
• Mechanical Effects of Diagnostic
Ultrasound 7
• Non-medical Use of Diagnostic
Ultrasound 8
2. Development of 3D Ultrasound
10
Kazunori Baba
• Introduction 10
• What Can 3D Ultrasound Do? 10
• Technical Aspects of 3D Ultrasound 11
• Practical Tips 21
3. Artifacts, Pitfalls and Normal Variants ............ 26
Ivica Zalud, Frederico Rocha
• Introduction 26
• Definition 26
• Mechanism 27
• Classification 27
• Reverberation 27
• Shadowing 28
• Enhancement 29
• Mirror Artifacts 29

• Refraction (Duplication) and Side Lobes 30
• Other Artifacts 30
• Doppler Ultrasound Artifacts 30
• 3D Ultrasound Artifacts 33
4. Routine Use of Obstetric Ultrasound ............... 35
Geeta Sharma, Stephen T Chasen,
Frank A Chervenak
• Introduction 35
• Basic Ultrasound 35

• Safety 36
• Guidelines for the Use of Obstetric
Ultrasound 37
• Randomized Controlled Trials of Routine
Ultrasound 39
• Critique of Radius Trial 43
• Meta-analyses of Randomized Controlled
Trials 44
• Diagnostic Ability of Routine Ultrasound 45
• First Trimester Ultrasonography 49
• Ethical Dimensions 50
5. Medicolegal Issues in Obstetric and
Gynecologic Ultrasound ....................................... 56
Frank A Chervenak, Judith L Chervenak
• Introduction 56
• Medical Negligence 56
• Guidelines 57
• Instrumentation and Safety 57
• Documentation 57
• Indications 57

• Examination Content 58
• Quality Control 59
• Litigation Related to Ultrasound 59
• Non-medical Use of Ultrasonography 59

SECTION 2: OBSTETRICS
6. Fetal and Maternal Physiology and
Ultrasound Diagnosis ........................................... 63
Aida Salihagic Kadic, Maja Predojevic,
Asim Kurjak
• Introduction 63
• Placenta 63
• Development of the Placenta 63
• Abnormal Placental Development and
Ultrasound 65
• Functions of the Placenta 67
7. Ultrasound Markers of Implantation ................ 92
Luis T Mercé, Maria J Barco, Asim Kurjak
• Introduction 92
• Ultrasound Implantation Markers 92
8. Normal and Abnormal Early Pregnancy ........ 106
Ulrich Honemeyer, Asim Kurjak, Giovanni Monni
• Introduction 106
• Normal Early Pregnancy 106


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Donald School Textbook of Ultrasound in Obstetrics and Gynecology
• Early Pregnancy Failure and Vaginal

Bleeding 113
• Missed Abortion 115
• Blighted Ovum
(Anembryonic Pregnancy) 117
• Intrauterine Hematomas 118
• Ectopic Pregnancy 120
• Early Pregnancy Loss 120

9. Ectopic Pregnancy: Diagnosing and
Treating the Challenge ....................................... 130
Sanja Kupesic Plavsic, Nadah Zafar,
Ulrich Honemeyer
• Introduction 130
• Role of Biochemical Markers in
Ectopic Pregnancy 131
• Role of Ultrasound in the Diagnosis of
an Ectopic Pregnancy 131
• Other Sites of Implantation 137
• Therapy 143
10. Sonographic Determination of
Gestational Age .................................................... 149
Robin B Kalish
• Introduction 149
• Assessment of Gestational Age by Last
Menstrual Period (LMP) 149
• Multifetal Pregnancies 153
• Choosing a Due Date 154
• Ultrasound Pitfalls 155
11. Trophoblastic Diseases....................................... 157
Kazuo Maeda, Asim Kurjak, Gino Varga,

Ulrich Honemeyer
• Introduction 157
• Classification, Development and
Pathology 157
• Complete Hydatidiform Mole 157
• Partial Hydatidiform Mole 158
• Invasive Hydatidiform Mole 158
• Choriocarcinoma 158
• Placental Site Trophoblastic Tumor 160
• Epithelioid Trophoblastic Tumor 160
• Persistent Trophoblastic Disease 160
• Symptoms of Gestational Trophoblastic
Disease 161
• Diagnosis of Gestational Trophoblastic
Disease 161
• Therapy of Trophoblastic Diseases 169
12. First-Trimester Ultrasound Screening for
Fetal Anomalies ................................................... 174
Jon Hyett, Jiri Sonek
• Introduction 174
• An Argument for Screening in the
First Trimester 175

• Elements of First-trimester Fetal
Screening 176
• Quality Assurance in First-trimester
Ultrasound 186
• Screening Multiple Pregnancies for
Down Syndrome 187
• First Trimester Screening for Fetal

Anomalies Other than Chromosomal
Defects 188
13. Fetal Anatomical Survey during SecondTrimester Screening Examination .................... 199
Vincenzo D’ Addario, Vincenzo Pinto,
Luca Di Cagno, Armando Pintucci
• Introduction 199
• Head and Brain 199
• Spine 202
• Chest 202
• Abdomen 205
• Limbs 208
14. Fetal Biometry ...................................................... 213
Frederico Rocha, Ivica Zalud
• Introduction 213
• First Trimester Measurements 213
• Second-trimester Measurements 215
15. Ultrasound and Doppler Management of
Intrauterine Growth Restriction ....................... 220
José M Carrera, Francese Figueras, Eva Meler
• Introduction 220
• Definitions 220
• Classification 221
• Incidence 221
• Screening 221
• Diagnosis 221
• Diagnosis of the Type of SGA 224
• Study of Fetal Deterioration 225
• Obstetric Management 228
16. Fetal Central Nervous System .......................... 233
Ritsuko K Pooh, Kyong Hon Pooh

• Introduction 233
• Basic Anatomical Knowledge of the
Brain 233
• Ventriculomegaly and Hydrocephalus 242
• Congenital Central Nervous System
Anomalies 248
• Acquired Brain Abnormalities In Utero 266
• Future Aspect 272
17. Pathology of the Fetal Neck .............................. 277
Radu Vladareanu, Mona Zvanca, Cristian Andrei
• Introduction 277
• Abnormal Development of Fetal Neck 277


Contents
18. Detection of Limb Malformations—
The Role of 3D/4D Ultrasound ......................... 288
Eberhard Merz
• Introduction 288
• Incidence of Limb Anomalies 288
• 3D Ultrasound Appearance of
the Limbs/Fetal Skeleton 288
• 4D Ultrasound Appearance of
the Limbs/Fetal Skeleton 289
• Transvaginal/Transabdominal Ultrasound
Examination of the Limbs/Fetal
Skeleton 291
• General Aspects of the Sonographic
Detection of Limb Malformations 291
19. The Fetal Thorax .................................................. 299

Aleksandar Ljubic, Aleksandra Novakov,
Aleksandar Cetkovic
• Introduction 299
• Developmental Anatomy and
Ultrasonographic Correlations 299
• Scanning Techniques 301
• Pathology 301
• Cystic Adenomatoid Malformation 303
• Fetal Pleural Effusions 305
• Lung Sequestration 306
• Congenital Cystic Lung Lesions 308
20. Three- and Four-dimensional Evaluation
of the Fetal Heart ................................................. 310
Carmina Comas Gabriel
• Introduction 310
• Impact of Congenital Heart Diseases:
Epidemiology and Population at Risk 310
• Prenatal Diagnosis of Congenital Heart
Diseases: Current Situation 311
• History of Fetal Echocardiography 312
• New Perspectives in Three- and Fourdimensional Fetal Echocardiography 313
• Clinical Application of 3D or 4D in
Fetal Cardiovascular System 315
• Spatiotemporal Imaging Correlation:
A New Approach to Three- and Fourdimensional Evaluation of the
Fetal Heart 316
• Technical Bases 316
• Advantages 318
• Limitations 321
• Current Applications and New

Perspectives 322
• First Spanish Study in Spatiotemporal
Image Correlation Technology 326
• Comment 329

xvii

21. Application of Spatial and Temporal
Image Correlation in the Fetal Heart
Evaluation .............................................................. 333
Marcin Wiechec, Agnieszka Nocun, Jill Beithon
• Introduction 333
• Technical Considerations 333
• The Process of Fetal Heart Assessment
in Stic Mode 334
• The Preparation of the 2D Image and
the Stic Volume Acquisition 334
• Image Quality Assessment 338
• Orientation 341
• Review 342
22. Malformations of the Gastrointestinal
System .................................................................... 361
Vincenzo D’ Addario, Cristina A Rossi,
Luca Di Cagno
• Introduction 361
• Anterior Abdominal Wall Defects 362
• Diaphragmatic Defects 366
• Bowel Disorders 369
• Non-bowel Cystic Masses 373
23. Diagnostic Sonography of Fetal Urinary

Tract Anomalies ................................................... 376
Zoltán Tóth, András Tankó, Zoltán Papp
• Introduction 376
• Ultrasound Imaging of Normal
Fetal Kidneys and Urinary Tract 377
• Renal Agenesis 378
• Cystic Renal Dysplasia 380
• Obstructive Uropathy 382
• Renal Tumors 389
• Determination of Fetal Renal Function 389
• Treatment of Prenatally Diagnosed
Renal and Urinary Tract Anomalies 390
24. The Fetal Musculoskeletal System .................. 393
Carlota Rodó, Elena Carreras, Nuria Toran,
Romina Castagno, Teresa Higueras,
Silvia Arévalo, Lluis Cabero
• Introduction 393
• Normal Ultrasound Appearance of
Fetal Skeleton 393
• Osteochondrodysplasias 397
25. Sonographic Assessment of the
Umbilical Cord ..................................................... 425
Edoardo Di Naro, Luigi Raio, Antonella Cromi,
Alessandra Giocolano
• Introduction 425
• Morphology 425
• “Lean” Umbilical Cord 426


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Donald School Textbook of Ultrasound in Obstetrics and Gynecology
•
•
•
•
•

Large Umbilical Cord 427
Discordant Umbilical Artery 428
Single Umbilical Artery (SUA) 429
Umbilical Cord Angioarchitecture 430
Umbilical Cord and Aneuploidies 433

• Ultrasonography for Fetal Morphology
Evaluation 486
• Ultrasound Technology and Advancement
in Screening 487
• Screening Methods and Tests 489

26. Clinical Aspects of Ultrasound
Evaluation of the Placenta ................................. 436
Ashok Khurana
• Introduction 436
• Embryological Considerations in
Understanding Placental Disease 436
• Abnormalities of Placental Shape 440
• The Concept of Placental
Trophotropism 440
• Placenta Accreta 442

• The Retroplacental Space, Placental
Hematomas and Placental Abruption 445
• Nontrophoblastic Placental Tumors 446
• Gestational Trophoblastic Disease 446
• Placental Location 447
• Three Dimensional Power Doppler (3DPD)
of the Placenta 450
27. Measurement of Cervical Length ..................... 455
Oliver Vasilj, Berivoj Miskovic
• Introduction 455
• General Facts About Uterine Cervix 455

30. Ultrasound in the Management of
the Alloimmunized Pregnancy ......................... 492
Daniel W Skupski
• Introduction 492
• History 492
• Diagnosis 493
• Management 495
• Alloimmune Thrombocytopenia 497
31. Doppler Sonography in Obstetrics .................. 499
A Kubilay Ertan, H Alper Tanriverdi
• Introduction 499
• The Safety of Doppler Ultrasound
in Obstetrics 499
• Dependency of Doppler Flow Velocity
Waveforms on Gestational Age 500
• Changes in Doppler Sonographic Results
During the Course of Pregnancy and
Complicated Pregnancies 501

• Fetal Venous Circulation 509
• Uteroplacental Perfusion 513

28. Monochorionicity: Unveiling the Black Box ... 460
Alexandra Matias, Nuno Montenegro,
Isaac Blickstein
• Introduction 460
• The Monozygosity Phenomenon 461
• How Much Identical are Monozygotic
Twins? 463
• The Limits of Zygosity Testing:
Postnatal Importance 466
• Monochorionic Pregnancy as a High Risk
Pregnancy: Twin-to-twin Transfusion
Syndrome as a Paradigm to Treat 470
• Discordance of Fetal Growth: What is
Adaptation, Promotion and Growth
Restriction in Multiples? 474
• Multiples and Cerebral Palsy: The Effect
of Prematurity or More? 475
29. Ultrasonography and Birth Defects ................. 480
Narendra Malhotra, Jaideep Malhotra,
Sakshi Tomar, Neharika Malhotra, Jai Prakash Rao
• Introduction 480
• Causes 481
• Ultrasound for Congenital Defects 482
• USG Extra Fetal Evaluation 485

32. Postpartum Ultrasound ...................................... 521
Ajlana Mulic-Lutvica

• Introduction 521
• Normal Puerperium 521
• Three-dimensional Ultrasound
Postpartum 525
• Retained Placental Tissue 526
• Postpartum Endometritis 529
• Uncommon But Potentially Life-threatening
Causes of Postpartum Bleeding 533
• Congenital Uterine Malformations 534
33. Three-Dimensional Sonoembryology ............. 540
Ritsuko K Pooh, Kohei Shiota, Asim Kurjak
• Introduction 540
• Modern Embryology by Magnetic Resonance
Microscopy and Computer Graphics 540
• Normal Embryo Visualization by Threedimensional Sonoembryology 541
• Fetal Abnormalities in Early Gestation 547
34. 3D Ultrasound in the Visualization of
Fetal Anatomy in the Three Trimesters of
Pregnancy .............................................................. 559
Giovanni Centini, Gabriele Centini,
Lucia Rosignoli, Mario Lituania
• Introduction 559


Contents

35.

36.

37.

38.

39.

• The First Trimester of Pregnancy 562
• The Second and Third Trimesters 586
3D Ultrasound in Detection of Fetal
Anomalies .............................................................. 621
Ritsuko K Pooh, Asim Kurjak
• Introduction 621
• Prenatal Diagnosis of Anatomical
Congenital Anomalies 624
Fetal Behavior ....................................................... 640
Zehra N Kavak, Tevfik Yoldemir
• Introduction 640
• Technical Aspects of 4D Ultrasound 641
• Technical Aspects of Real-time
3D Ultrasound 641
• Imaging During the First and Early
Second Trimesters 641
• Imaging During Late Second and
Third Trimesters 641
• 4D Ultrasonographic Observation
of the Fetal Face 642
• 4D Ultrasonographic Observation
of the Entire Fetal Body 643
• Comparison of Fetal Behavior in
High Risk and Normal Pregnancies 644

Fetal Behavior Assessed by 4D Sonography . 649
Asim Kurjak, Badreldeen Ahmed, Berivoj Miskovic,
Maja Predojevic, Aida Salihagic Kadic
• Introduction 649
• Basic Technology of the 4D Sonography
in the Assessment of Fetal Behavior 649
Ultrasound-Guided Fetal Invasive
Procedures ............................................................. 671
Aris J Antsaklis, George A Partsinevelos
• Introduction 671
• Amniocentesis 671
• Chorionic Villus Sampling 674
• Fetal Blood Sampling 676
• Celocentesis 677
• Embryoscopy-Fetoscopy 678
• Multifetal Pregnancy Reduction and
Selective Termination 681
• Twin-to-twin Transfusion Syndrome 683
• Fetal Biopsy Procedures in Prenatal
Diagnosis 685
• Congenital Diaphragmatic Hernia 686
• Fetal Pleural Effusion 687
• Interventional Fetal Cardiology 689
Chorionic Villus Sampling................................ 695
Cihat en
• Introduction 695
• Technical Aspects of the Procedure 696

xix

• Complications, Pregnancy Loss and
Safety 698
40. Amniocentesis and Fetal Blood Sampling ..... 705
Aris J Antsaklis, George A Partsinevelos
• Introduction 705
• Amniocentesis 705
• Fetal Blood Sampling 709
41. Invasive Genetic Studies in
Multiple Pregnancy ............................................. 712
Aris J Antsaklis, George A Partsinevelos
• Introduction 712
• Incidence of Structural Fetal Anomalies
in Multiples 713
• Risk of Aneuploidy in Multiples 713
• Indications for Prenatal Diagnosis 714
• Invasive Procedures for Prenatal
Diagnosis 714
• Fetal Blood Sampling 717
42. Magnetic Resonance Imaging: How to
Use it During Pregnancy? .................................. 720
Ichiro Kawabata, Yuichiro Takahashi,
Shigenori Iwagaki
• Introduction 720
• Safety of MRI 720
• Indication and Procedures for MRI
during Pregnancy 721
43. 3D Sonography in the Evaluation of
Normal and Abnormal Fetal Face .................... 730
Guillermo Azumendi, Asim Kurjak
• Introduction 730

• Advantages and Limitations of 3D
Ultrasound 750
• Assessment of Fetal Facial Expression 752
• Optimum Conditions for 3D Scanning
of the Fetal Face 752

SECTION 3: GYNECOLOGY
44. Normal Female Reproductive Anatomy ......... 759
Sanja Kupesic Plavsic, Bhargavi Patham,
Ulrich Honemeyer, Asim Kurjak
• Introduction 759
• Uterus 759
• Fallopian Tube 763
• Ovaries 763
45. Uterine Lesions: Advances in
Ultrasound Diagnosis ......................................... 770
Sanja Kupesic Plavsic, Bhargavi Patham,
Ulrich Honemeyer, Asim Kurjak
• Introduction 770


xx

Donald School Textbook of Ultrasound in Obstetrics and Gynecology
•
•
•
•
•
•

•
•

Normal Uterus 770
Endometrial Polyps 770
Intrauterine Synechiae (Adhesions) 774
Adenomyosis 774
Endometrial Hyperplasia 775
Endometrial Carcinoma 777
Leiomyoma 780
Leiomyosarcoma 783

46. Ultrasound and Uterine Fibroid ....................... 788
Aleksandar Ljubic, Tatjana Bozanovic,
Srboljub Milicevic
• Introduction 788
• Elastography 792
• Treatment 793
• Uterine Fibroid and Pregnancy 799
47. Three-Dimensional Static Ultrasound and
3D Power Doppler in Gynecologic
Pelvic Tumors ....................................................... 803
Juan Luis Alcázar
• Introduction 803
• Endometrial Cancer 803
• Uterine Leiomyomas and Sarcomas 808
• Cervical Cancer 809
48. Ultrasound in Human Reproduction .............. 818
Veljko Vlaisavljevic, Marko Dosen
• Introduction 818

• Folliculogenesis 818
49. New Insights into the Fallopian Tube
Ultrasound ............................................................. 829
Sanja Kupesic, Bhargavi Patham,
Ulrich Honemeyer, Asim Kurjak
• Introduction 829
• Pelvic Inflammatory Disease 829
• Ultrasound Findings 830
• Benign Tumors of the Fallopian Tube 836
• Malignant Tumors of the Fallopian Tube 837
50. The Use of Sonographic Imaging with
Infertility Patients ............................................... 843
Sanja Kupesic Plavsic, Nadah Zafar,
Guillermo Azumendi
• Introduction 843
• Uterine Causes of Infertility 843
• Ovarian Causes of Infertility 856
• Polycystic Ovarian Syndrome 861
• Tubal Causes of Infertility 867
51. Newer Developments in Ultrasound in
Infertility................................................................ 872
Radu Vladareanu, Cristian Andrei,
Mona Zvanca
• Introduction 872

• Uterine/Endometrial Factors of
Infertility 872
• Endometriosis 885
• Ovarian Factor in Infertility 888
• Tubal Factor of Infertility 894

• Sonohysterography 894
52. 2D and 3D Saline Infusion Sonography and
Hystero-Contrast-Salpingography ................... 900
Sanja Kupesic Plavsic, Branko M Plavsic
• Introduction 900
• Ultrasound Assessment of the Uterus
and the Fallopian Tubes 901
• Three-dimensional Hy-co-sy 908
53. Guided Procedures Using Transvaginal
Sonography ........................................................... 915
Sanja Kupesic Plavsic, Nadah Zafar,
Asim Kurjak
• Introduction 915
• Transvaginal Puncture Procedures 916
• Conservative Management of an Ectopic
Pregnancy 920
• Other Applications 921
54. Ultrasound in the Postmenopause ................... 924
Martina Ujevic, Biserka Funduk Kurjak,
Boris Ujevic
• Introduction 924
• Challenges of the Postmenopause 925
• Instrumentation 925
• Scanning in the Postmenopause 925
• The Postmenopausal Ovary 926
• The Postmenopausal Uterus 931
• The Postmenopausal Endometrium 933
55. The Use of Ultrasound as an Adjunct to
the Physical Examination for the Evaluation
of Gynecologic and Obstetric Causes of

Acute Pelvic Pain ................................................. 942
Sanja Kupesic Plavsic, Nadah Zafar,
Ulrich Honemeyer, Branko M Plavsic
• Introduction 942
• Gynecologic Etiologies of Acute Pelvic
Pain 942
56. Three-Dimensional and Four-Dimensional
Sonography in Gynecological Patients ........... 957
Ashok Khurana
• Introduction 957
• Technological Advances 957
57. Ultrasound in Urogynecology ........................... 992
Ashok Khurana
• Introduction 992


Contents
• Clinical Considerations 992
• Technical Concepts, Norms and
Anatomical Considerations 993
58. USG Role in Perinatal Infection .................... 1003
Alaa Ebrashy
• Introduction 1003
• Ultrasound Features in Congenital
Infection 1003
Index

xxi

• Etiology and Pathogenesis in Intrauterine

Infection 1004
• Prenatal Management of Specific Congenital
Infections Using Ultrasound Markers and
Invasive Procedures 1006
• Management 1009

...................................................................................................................................................................................1013


SECTION

1
General Aspects


1

CHAPTER

Safety of Ultrasound in
Obstetrics and Gynecology
Kazuo Maeda

INTRODUCTION
Although no adverse effects of ultrasound diagnosis have been reported, bioeffect and safety issues have
been studied and discussed by various medical ultrasound organizations.1-9 It is emphasized that, for safe
use, ultrasonic examinations are only performed when medically indicated. Secondly, the users are responsible
for safety and should recognize that biological tissues of developing embryos and fetuses may be damaged
by intense ultrasound.6 The main biological effect is the thermal effect due to the temperature rise induced by
ultrasound absorption, because teratogenicity was reported in fetal animals exposed to high temperature.2

Non-thermal effects of ultrasound are inertial cavitation and other mechanical effects. Diagnostic ultrasound
users are requested to know the ultrasonic intensity of their devices, the mechanisms of ultrasound bioeffects and usage of their instruments prudently. No hazardous thermal effects are expected when the
temperature rise in exposed tissue is less than 1.5ºC and local temperature is lower than 38.5ºC,1 the fetus
was tolerable to 50 hours exposure up to 2oC rise,5 while 5 minutes at 41ºC can be hazardous to the tissue.1
No hazardous thermal effects are expected in common B-mode imaging devices because there is minimum
heat production due to low ultrasound intensity. World Federation of Ultrasound in Medicine and Biology
(WFUMB) concluded that the use of simple imaging equipment is not contraindicated on thermal grounds.1
Simple transvaginal B-mode, simple three dimensional (3D) and four dimensional (4D) imaging are included
in this category. The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) also stated
the safe use of Doppler ultrasound.7 More practical plans on the safe use of Doppler ultrasound from the
user’s view is discussed in this chapter. Direct subject heating with transvaginal transducer is avoided where
the transducer should be lower than 41ºC.
Ultrasound bioeffects are estimated by thermal effect with thermal index (TI), mechanical effects with mechanical index (MI) and also by output ultrasound power, e.g. the safety of fetal heart detector and simple B-mode
equipments was established by the Japanese Industrial Standard regulating the output power below spatial
peak temporal average (SPTA) 10 mW/cm2 in 1980, where the level was 1/100 of hazardous threshold of
continuous wave ultrasound, which was SPTA 1 W/cm2 in our study.8,10-11 However, ultrasound safety has
been discussed again after introduction of Doppler flow velocity measurements which definitely needed higher
ultrasound intensity than simple B-mode.

DIAGNOSTIC ULTRASOUND INSTRUMENTS
AND ULTRASOUND INTENSITY
Ultrasonic imaging devices and Doppler blood flow
studies utilize pulsed wave (PW) ultrasound while

continuous wave (CW) ultrasound is applied in fetal
functional tests (Table 1.1). The ultrasound intensity
differs between PW and CW machines (Fig. 1.1), i.e.
temporal peak intensity is large in PW and weak in CW
ultrasound, while temporal average intensity is almost

4

Section 1 / General Aspects

TABLE 1.1
Diagnostic ultrasound
Pulsed wave (PW) for imaging
and blood flow studies

Continuous wave (CW) for
the functional tests

Real-time B-mode

Fetal heart Doppler detector

3D/4D ultrasound

Fetal heart rate tracing

Pulsed Doppler flow velocity
wave

Fetal movement record
(actocardiogram)

Color/power Doppler flow
mapping

CW Doppler flow velocity
wave

High peak and low temporal
average intensities in simple
B-mode and 3D/4D ultrasound

Low peak and temporal
average intensities

High peak and average
intensities in pulsed Doppler flow
velocity wave
High peak intensity and medium
average intensity in color/power
Doppler flow mapping

identical in simple PW B-mode imaging device and CW
machines (Table 1.1). However, pulsed Doppler flow
velocity measurement needs high peak and average
intensity due to its long pulse and high repetition
frequency (Figs 1.1A and B). The temporal average
intensity of color and power Doppler flow mapping is
lower than pulsed Doppler but higher than simple Bmode machine.

ULTRASOUND INTENSITY OF DOPPLER
ULTRASOUND
The maximum intensity of adult Doppler ultrasound
was 1–3 W/cm2, which was as high as the ultrasonic
physiotherapy for the tissue heating, where the

transducer was always moved on the bone and young
patient’s bone and pregnant woman were contraindicated from the concern on ultrasound safety. The
difference between therapeutic ultrasound and pulsed
Doppler device is the exposure duration, which is short
in Doppler flow measurement. Thermal effect is
therefore a big concern in Doppler ultrasound. Temperature rises not only at the sample volume but also in all
tissues passed by the ultrasound beam. Ultrasound
intensity is lower in color/power Doppler flow mapping
than pulsed Doppler because of the scanning motion of
Doppler ultrasound beam in the region of interest (ROI).
Temporal average intensity of color Doppler is lower
than adult Doppler devices and within the limit of nonhazardous FDA regulation which is 720 mW/cm2.
Thermal effect is discussed in the first place in pulsed

Figures 1.1A and B: Two types of diagnostic ultrasound
waves. (A) Pulse wave (PW): 1/t is repetition frequency;
(B) Continuous wave (CW)

Doppler, where the safety is determined by ultrasound
intensity and exposure duration.

THE EFFECT OF HEATING ON MAMMAL
FETUSES
Teratogenic effects were reported by biologists in the
exposure of mammal animal embryos and fetuses to
experimental high temperature of 39–50oC in various
mammals. The results are summarized in the National
Council for Radiation Protection and Measurement
(NCRP) report 2 in 1992, where a discrimination line
clearly separates hazardous and non-hazardous areas.

There is no hazard in the area under the line
determined by connecting high temperature/short
exposure and low temperature/long exposure points.
Non-hazardous exposure is as short as one minute in
43oC and infinite in physiological body temperature.
Absolute temperature is studied when the temperature
rise derived from TI is added 37 oC in ultrasound
exposure because TI is calculated in the worst case of
temperature elevation by the exposure to standard
tissue model.

NON-HAZARDOUS EXPOSURE TIME
OF THE FETUS TO THE HEAT
The revised safety statement on diagnostic ultrasound
of American Institute of Ultrasound in Medicine
(AIUM)5 published in 1998, is based on the NCRP
report2 in 1992, where inverse relation is found between
hazardous temperature level and exposure time. They
stated that the fetus tolerated 50 hours at 2oC rise
(absolute temperature was 39oC) and 1 min at 6oC rise
(43oC). They showed the relation of the temperature rise
(T) above 37oC and the non-hazardous exposure time
(t min) by the equation 1. The author modified the
equation 1 and obtained non-hazardous time (t min)
from the temperature rise with the equation 2;


CHAPTER 1 / Safety of Ultrasound in Obstetrics and Gynecology
TABLE 1.2
Non-hazardous exposure time (t min) to the temperature rise

above 37 o C and body temperature is estimated by the
equation 2
Temperature
rise
(oC)

Body
temperature
(o C)

Non-hazardous
exposure time; t
(t min)

Log t

1

38

1000.0

3.00

2

39

251.8

2.40

3

40

63.10

1.80

4

41

15.85

1.20

5

42

3.98

0.60

6

43

1.0

0

5

Doppler scanner, the TI, MI, transducer temperature
and other related indices are displayed on the monitor
screen when they are excessively high values3, making
the users to keep the safety of ultrasound diagnosis.
Obstetric setting should be confirmed before Doppler
flow velocity measurements during pregnancy, in order
to keep the safety of Doppler ultrasound. Ultrasonic
examinations should be done only by medical indications. Although ISUOG safety statement7 reported that
there is no reason to withhold the use of scanners that
have received current FDA clearance in the absence of
gas bodies, AIUM5 stated that for the current FDA
regulatory limit at 720 mW/cm 2, the best available
estimate of the maximum temperature increase can
exceed 2°C. Pulsed ultrasound intensity threshold to
suppress cultured cell-growth curve was 240 mW/cm2
in our studies. 10 The FDA regulation may be still
controversial from the opinions and reports.

Prevention of Thermal Damage due to
Ultrasound Exposure

Figure 1.2: Tolerable exposure time of animal fetuses to
the temperature rise and TI.
From the equation 2 in the text t = 10(3.6-0.6T)

T: temperature rise = thermal index (TI)
t: non-hazardous time (min)

T (°C) = 6 - {(log10 t)/0.6} - - - - - - - - (1)
t = 10(3 6-0 6T) - - - - - - - - - - - - - - - - - (2)
Relations of non-hazardous exposure time, temperature rise and body temperature are known by the
equation 2 (Table 1.2 and Fig. 1.2). The thermal safety
of ultrasound is known by the TI which is theoretically
equal to the temperature rise.

STRATEGY FOR THE SAFETY OF
DIAGNOSTIC ULTRASOUND EQUIPMENTS
The safety to electrical and mechanical impacts is
proved in ultrasound devices by the manufacturer
under international and domestic guidelines. In a

The TI is a useful index of the temperature rise by
ultrasound exposure. Standard tissue models are used
in the TI determination in the worst case, i.e. TI is
determined by the highest temperature rise. One TI
stands for one degree celsius temperature elevation, e.g.
temperature rises for 3oC and absolute temperature is
40oC if TI is 3. Since local temperature rise is estimated
only by TI at present, TI is the index to estimate tissue
temperature in ultrasound examination, to study
ultrasonic thermal effect and to avoid possible thermal
damage of intense ultrasound. Soft tissue TI (TIS) is used
in case of embryo of no bone before 10 weeks of
pregnancy and bone TI (TIB) is applied in the fetus with
bone.

No hazardous thermal effect is expected when the
temperature rise of exposed tissue is less than 1.5oC.
An ultrasound examination is totally safe with the TI
less than one in daily practice, particularly in the
screening of pregnancy and research works. The output
power is reduced if the displayed TI is higher than one,
until the TI is lower than one. Revised safety statement
AIUM5 stated that equal or less than 2°C temperature
rise above 37°C was tolerated up to 50 hours and that
the upper limit of safe exposure duration was 16 min
at 4°C rise and 1 min at 6°C rise above normal,
respectively. The AIUM opinion on the effect of high
temperature is similar to the report of NCRP.2
Although the statement5 is useful in a retrospective
criticism after the ultrasound exposure, fetal exposure
with the temperature rise for 4–6°C may be medically


6

Section 1 / General Aspects

controversial because absolute temperature is 41–43°C.
Non-hazardous exposure time at such temperature
higher than 40oC is critically short,2,5 where remained
safe margin is very narrow, excess heating may not be
completely avoided in the highest temperature. The
author proposes practically applicable safe exposure
time in the prospective situation before a Doppler
ultrasound diagnosis.

TABLE 1.3
Thermal index (TI), tissue temperature, non-hazardous
exposure time based on the NCRP report 2, the safety factors
and exposure time to ultrasound are listed. Although the user
can voluntarily set the safety factor and exposure time, the
author recommends to choose the safety factor at 50 and
exposure time at 5 min when TI is 2
TI

Absolute
temperature
(°C)

Non-hazardous
exposure time
of NCRP
report 2
(min)

Exposure time (min)
obtained by dividing nonhazardous exposure time
of NCRP report 2 by
various safety factors
Safety Factor
3
10 50
100

6

43

1

0.3

0.1

0.02 0.01
(no use)

4

41

16

5

0.2

0.03 0.02
(no use)

3

40

64

21

6

1

0.6

2

39

256

85

25

5

2.5

Two Modes in Ultrasonic Exposure Duration
Two modes can be used in the Doppler ultrasound. The
mode of TI lower than one (AIUM) or the temperature
rise below 1.5°C (WFUMB) after temperature equilibrium can be adopted for the infinite exposure in the
research work or pregnancy screening where the
exposure time is hardly expected before the study.
Diagnostic pulsed Doppler study is another situation

where users require improved Doppler flow wave by
the higher TI than one. Some ultrasound lecture showed
us higher TI than one in Doppler studies where the
safety is proved by short exposure time. The technique
was the same as the NCRP report, where short exposure
to high temperature was nonhazardous. Doppler
examinations with higher TI than one can be permitted
by short exposure.
Non-hazardous exposure time to high temperature,
temperature rise and high TI is obtained by the
application of the equation 2 (Table 1.2 and Fig. 1.2).
Exposure time is 250 min when TI is 2 and temperature
is 39oC, it is 1hr if TI is 3 and temperature 40oC and
15 min when TI is 4 and the temperature is 41oC. The
fetus is tolerable for 4min if the TI is 5 and absolute
temperature is 42oC, and finally, one min’ exposure time
is allowed, if TI is 6 and temperature is 43oC, in the
revised safety statement of AIUM.5 The statement is
useful in the confirmation of Doppler ultrasound safety
in the past examination. On the other hand, however,
the setting of exposure time is required in prospective
situation before examination.

Prospective Setting of Exposure
Time before Examination
Exposure time is preset before the Doppler examination
in the case of higher TI than one with the intention to
improve Doppler flow wave. The author recommends
to determine actual exposure time by dividing the nonhazardous time of NRCP with the “safety factor” at 50
before every examination with high TI (Tables 1.2 and

1.3, Fig. 1.2). The method was similar to the past
regulation of simple B-mode devices in Japan, where
threshold intensity was divided by 100 and the output

power was regulated to be lower than 10 mW/cm2 and
the safety was generally accepted before the Doppler
flow studies. As ultrasound intensity may increase for
about three times if standing wave is present, three is
the lowest safety factor. In addition, the intensity may
increase by the distortion of ultrasonic wave measured
by A/B ratio and possible estimation error of TI.9 These
situations are added up to the safety factor and therefore, the author proposes the safety factor up to 50.
For example, non-hazardous exposure time limit is
252 min at 39°C in AIUM statements (Table 1.2), where
the temperature rises for 2°C and corresponding TI is
2. In author’s recommendation, 252 min are divided by
50 and actual exposure time is 5 min. By the same
manner, 1 min exposure time is preset when TI is 3
(Table 1.3).
Higher TI than 3 is not recommended because
absolute temperature is higher than 40°C that will be
medically controversial. The author’s setting is close to
the BMUS safety statement 11 where the exposure time
is 4 min when TI is 2 and 1 min if TI is 2.5.

Other Thermal Issues
Caution should be paid for the temperature of the tissue
exposed to Doppler ultrasound in febrile patients, where
the basic temperature is higher than 37°C.1 For example,
if TI is 2 in 38°C febrile patient, the temperature rise

above physiologic condition is 3°C, the situation is the
same as TI 3 in nonfebrile normal temperature case, and


CHAPTER 1 / Safety of Ultrasound in Obstetrics and Gynecology
therefore, 1 minute’s exposure time is appropriate.
Surface temperature of transvaginal transducer should
not be 41oC or more.1 The user should concern the direct
heating of attached tissues and pelvic organs.
Animal fetal skull was heated and the temperature
elevation was more than 4°C by the exposure to intense
ultrasound.6 Thermal damage of the brain surface can
not be denied. Therefore, maximal intensity of Doppler
ultrasound is inadvisable in intracranial flow studies
even in late pregnancy. Exposure duration and TI
should be documented in patient records in the study
where TI is higher than one. The safety indices including
TI and MI are documented in the “Methods” of Doppler
ultrasound study reports.

The Safety of 3D Ultrasound
Simple B-mode imaging is not concerned for the thermal
effect, because of its very low output intensity, e.g. the
output of B-mode machine is regulated in Japan10 to be
lower than SPTA 10 mW/cm2. The gray level data is
acquired in 3D imaging by repeated scan of real-time B
mode array transducer, the scans are completed within
a few seconds, the image data are stored in the computer
memory and the unique 3D images are processed in
the computer after the ultrasound exposure. A point of

fetal body would be exposed to ultrasound infrequently
in whole scans. Therefore, 3D ultrasound exposure at a
point of the fetus or embryo and possible heating caused
by ultrasound would be the same as a simple B-mode.
Accordingly, possible temperature rise and thermal
effect in 3D ultrasound are almost the same as simple
B-mode, therefore 3D technique will be as safe as the
simple B-mode ultrasound in its thermal effect. Doppler
flow study accompanied by 3D ultrasound is regulated
by its own thermal effects. The mechanical effect of
pulsed ultrasound in 3D is equal to the simple B-mode
and it is determined by its temporal peak (TP) intensity,
sound pressure or mechanical index (MI). The 3D
ultrasound is safe in mechanical effects if the MI is lower
than one, as commonly recommended.

The Safety of 4D Ultrasound
Although the 4D ultrasound image is obtained by
computer processing of 10–24 frames of fetal 3D pictures
in a second, most fetal parts are expected not to be
exposed to ultrasound repeatedly, because the fetus is
moving and therefore a fetal part continuously changes
its position. Thermal effect of ultrasound will not be
concerned in 4D, despite large number of ultrasound
scan is repeated, because simple B-mode is the base of
3D and 4D imaging and thermal effect is not concerned

7

in the B-mode. The 4D ultrasound is considered to be

long scan of simple B-mode scan. Therefore, there will
be no problem caused by ultrasonic thermal effect in
4D surface imaging. Although, theoretically, there is no
limit of B-mode ultrasound examination if the thermal
index (TI) is less than one, the duration of 4D fetal
studies would be limited in diagnostic or scientific
purposes. Doppler study accompanied by 4D ultrasound is regulated by its own thermal effects. As for
the safety of mechanical effect of pulsed ultrasound,
4D ultrasound is safe to the fetus or embryo when the
MI is less than one and the duration is prudent.

MECHANICAL EFFECTS OF DIAGNOSTIC
ULTRASOUND
Mechanical index (MI) is used for the estimation of
mechanical bioeffect where MI is rarefactional sound
pressure (Pr) expressed in Mega-Pascal (MPa), divided
by square root of ultrasound frequency in MHz, e.g.
MI is 2 when Pr is 2 MPa and the US frequency is
1 MHz. MI indicates non-thermal effect of ultrasound
particularly for the cavitation in the presence of gas
bubbles in liquids. Although gas containing contrast
medium is still infrequent in OB/GY, its common use
in adult circulation should be carefully studied. It is
also taken into account that common B-mode is weak
in thermal effect, while its pulse peak intensity is not
much different from Doppler machines. However, the
free radical formed by the inertial cavitation hardly
reaches floating cells in the fluid due to short life span
and no cavitation may occur within the cell due to high
viscosity of cell plasma. Effects of acoustic streaming,

capillary blood cell stasis by standing waves or the
positive ultrasound pressure require further basic
studies. Since hemorrhages are found in neonatal animal
lung by the exposure to intense ultrasound, lower MI
than one should be used in neonatal lung examination.
Although recently the failure of neuronal cell migration
in fetal mouse brain was reported after exposure of
pregnant mouse to real time B-mode transducer with
high pulse average intensity, the report needed 30
minutes or more exposure time to develop the effect.12
AIUM stated that fetal mice exposed to ultrasound were
found to have small but detectable effects only after
extended duration of ultrasound exposure, conditions
beyond those commonly used in diagnostic ultrasound
imaging. The whole brain exposure in the rapidly
developing mouse brain used in this study differs
significantly from the short duration of diagnostic
ultrasound imaging to selected sites in the human fetus.


8

Section 1 / General Aspects

Similar opinions were stated by the Japan Society of
Ultrasound in Medicine and Japan Society of Biomedical
Engineering in Obstetrics and Gynecology.

NON-MEDICAL USE OF DIAGNOSTIC
ULTRASOUND

Although the use of diagnostic ultrasound should be
limited for medical purposes and users are responsible
to the safety of ultrasound, i.e. users must keep the
knowledge on possible ultrasound bioeffect and use the
ultrasound under the ALARA (as low as reasonably
achievable) principle, nonmedical ultrasound in entertainment or keepsake ultrasound, fetal portrait studios
or prenatal boutiques which record intrauterine fetal 3D/
4D ultrasound on DVD are recent problems concerning
ultrasound safety. There are also ethical concerning and
false reassuring problem in the topics.13-16
The WFUMB13 disapproves of the use of ultrasound
for the sole purpose of providing souvenir images of
the fetus. Because the safety of an ultrasound examination cannot be assured, the use of ultrasound without
medical benefit should be avoided. Furthermore,
ultrasound should be employed only by health
professionals who are well trained and updated in
ultrasound clinical usage and bioeffects. The use of
ultrasound to provide keepsake images or video of the
fetus may be acceptable if it is undertaken as part of
normal clinical diagnostic ultrasound examination,
provided that it does not increase exposure to the fetus.
Ultrasound imaging for nonmedical reasons is not
recommended unless carried out for education, training
or demonstration purposes. Live scanning of pregnant
models for equipment exhibition at ultrasound
congresses is considered a nonmedical practice that
should be prohibited since it provides no medical
benefit and afford potential risk to the fetus. When using
ultrasound for nonmedical reasons, the ultrasound
equipments display should be used to ensure that TI<0.5

and MI<0.3.13
The safe obstetric ultrasound intensity level was
reported to be one thermal index (1TI) and one mechanical index (1MI) in general opinions of medical
ultrasound authorities (Fig. 1.2). There can be possible
biological hazardous effects in the ultrasound intensity
above the levels. In particular case where the user’s
knowledge is abundant on the ultrasound safety, the
TI may be allowed to be 2 but the exposure time should
be limited less than 5 mins (Table 1.3).
In our detailed ultrasound radiation experiments
insulating the heating of the transducer in the

thermostat water, the cultured fetal amniotic origin cell
line floated in the culture medium held in ultrasound
translucent container was exposed quantitative ultrasound 20–30 mins and the cell growth curve was
compared to the sham of no radiation in the same
thermostat water. The cell growth curve showed no
difference to the sham below the SPTA 240 mW/cm2
(SPTP 20 W/cm 2) of pulsed ultrasound, while the
growth curve was suppressed after the exposure to the
output intensity ultrasound above the threshold output
intensity. 11 Since Japan Society of Ultrasonics in
Medicine authorized the results, Japan Industrial
Standard (JIS)10 regulated medical ultrasound output
intensity at the level lower than SPTA 10 mW2, afterwards the medical ultrasound safety was generally
recognized.
Although the regulated intensity is low level, the
standing wave in case of ultrasound reflection may
increase the intensity and the deformed pulsed ultrasound waves may further increase the intensity. The
prudent JIS setting will contribute the safety of medical

ultrasound even in its accidental increase, while possible
increase of output intensity to get further clear fetal
image in nonmedical entertainment will easily exceed
the safe threshold intensity level. The risk should be
prevented by the skilful medical staff with rich safety
knowledge and prudent use of diagnostic ultrasound
equipment.
In summary of the opinion of ultrasound safety
specialists, the non-medical use of diagnostic ultrasound
for solely entertainment is not recommended or not
permitted from the standpoint of diagnostic ultrasound.13-16

CONCLUSION
The strategies to keep the safety of each diagnostic
ultrasound equipments depends on their system,
because the thermal effect estimated by TI has been the
main criteria in the safety. Simple B-mode, 3D and 4D
ultrasound, fetal heart detector and fetal monitor, are
not contraindicated due to thermal effect because of
their low temporal average intensity. Pulsed Doppler
machines are the main target in the safety due to its
high temporal average intensity. Non-hazardous
exposure time of NCRP/AIUM criteria and the temperature rise estimated by TI are useful in retrospective
criticism on the past examination. The principle of safe
diagnostic ultrasound in daily practice is to keep the TI
below one, where obstetrical setting is useful. Research
works and pregnancy screening strictly follow the