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Preamble:

If you are a parent who located this website whilst seeking information about a finding on your baby's ultrasound scan, please note that this Thesis was directed at medical and paramedical professionals and offers opinions and suggestions TO THEM, not necessarily to their patients/clients (i.e YOU), concerning the unsuitability of offering an amniocentesis test for this finding alone. The argument is detailed and academic (i.e it looks 'boring'? - it is not a fancy informational website as such). Also its conclusion may not apply to your exact situation. However, you are of course welcome, indeed encouraged, to read!

Phillip Ramm GradDip US AMS.

The Choroid Plexus Cyst  Controversy 

 

 

The Paradigm of Cyst Criteria

Phillip L. Ramm, MIR, ARMIT, Grad Dip U/S (RMIT)

formerly Chief Sonographer

Fetal Welfare Lab

Westmead Hospital*

 

* at the time of submission, December 1996.

 

 

 

1.                  Introduction

1.1.                             The Atmosphere of Ultrasound

1.2.                             The Paradigm of Cyst Criteria

1.3.                             Purpose of This Study       

 

2.                  Development of the Choroid Plexus

2.1.                             Choroid Plexus Growth & Development

2.2.                             Stage I

2.1.                             Stage II

2.2.                             Stage III

2.3.                             Stage IV

2.4.                             Conclusion

3.                  What is a Choroid Plexus Cyst?       

3.1.                             Anatomical Definition

3.2.                             Ultrasound Definitions

3.3.                             Choroid Plexus “Pseudocyst

3.4.                             Conclusion

4.                  Geelong Hospital Choroid Plexus Cyst Survey

4.1.                             Initial Reason for the Survey

4.2.                             Methodology

4.3.                             Results

4.4.                             Conclusion

5.                  Technical Factors in the Rise of the CPC Controversy                  

5.1.                             Improved Equipment

5.2.                             Concentration on the Fetal Brain

5.3.                             Sonographer Skill & Training

6.                  Literature Search

6.1.                             Association with Chromosomal Abnormalities

6.2.                             Incidence of CPC

6.3.                             Rate of Aneuploidy versus Risk of Aneuploidy

6.4.                             Differences in the Referral Population and Indications for Scanning

6.5.                             Risk in Down Syndrome

6.6.                             Conclusion

7.                  The Paradigm is Established: Attempts to find Useful Criteria

7.1.                             Early Protocols used the Size, Bilaterality, Persistence Paradigm

7.2.                             Routine Amniocentesis

7.3.                             Anomaly Scan

7.4.                             Australian Protocols

7.5.                             Publishing Bias in Response to the Paradigm

7.6.                             Conclusion

8.                  Size                        

8.1.                             Large Size in Early Reports

8.2.                             Changing Size

8.3.                             Reviews of Size

8.4.                             Statistical Analysis

8.5.                             Conclusion

9.                  Bilaterality

9.1.                             Imaging Problems

9.2.                             Lower Hemisphere Preponderance

9.3.                             Statistical Analysis

9.4.                             Number of Cysts –  Confusion of Terminology

9.5.                             Conclusion

10.              Persistence / Late Disappearance

10.1.                          Early “Evidence” of Persistence

10.2.                          The Need for Reassurance

10.3.                          How Late is Late?

10.4.                          Lack of Concurrence in the Literature

10.5.                          Statistical Analysis

10.6.                          Conclusion

11.              Associated Abnormalities

11.1.                          Trisomy 18 Reviews, CPC and/or Other Abnormalities

11.2.                          CPC, Abnormalities and T18

11.3.                          Risk of “Isolated” CPC in Fetuses with T18

11.4.                          Malformation Rate

11.5.                          Statistical Analysis

11.6.                          Conclusion

12.              Ultrasound Detectable Abnormalities in Trisomy 18: Review and Discussion

12.1.                          Abnormal Cephalic Index

12.2.                          Strawberry Shaped Head

12.3.                          Small / Abnormal Cerebellum

12.4.                          Cisterna Magna > 9mm – Dandy Walker Malformation / Syndrome

12.5.                          Arnold-Chiari Malformation / Spinal Defects

12.6.                          Agenesis of Corpus Callosum

12.7.                          Cystic Hygroma

12.8.                          Nuchal Oedema / Translucency

12.9.                          Hypotelorism

12.10.                       Facial Cleft

12.11.                       Micrognathia

12.12.                       Small Ear

12.13.                       Cardiac Defects / Septal Defects

12.14.                       Renal Anomaly

12.15.                       Omphalocele / Exomphalos

12.16.                       Diaphragmatic Hernia

12.17.                       “Absent” Stomach (Presumed Oesophageal Atresia, OA)

12.18.                       Abnormal Extremities: Introduction

12.19.                       Radial Aplasia / Radial Ray Syndrome (Absent Thumb)

12.20.                       Overlapping Fingers / Clenched Fist (Camptodactyly) / Polydactyly

12.21.                       Talipes / Rockerbottom Feet / Short Hallux

12.22.                       Hydramnios

12.23.                       Intra-Uterine Growth Retardation

12.24.                       Two Vessel Cord (Single Umbilical Artery, SUA)

12.25.                       Allantoic / Cord Cysts

12.26.                       Signs of Other Chromosomal Abnormalities

12.27.                       Conclusion

13.              When is Karyotpying Indicated?

13.1.                          The “At-Risk” Patient

13.2.                          Biochemical and 1st Trimester Ultrasound Tests

13.3.                          Risk of Karyotyping

13.4.                          A Balance of Risks

13.5.                          The “Routine Scan” Has Become the “Routine Anomaly Scan”

13.6.                          Trials of Routine Ultrasound

13.7.                          How Well Are We Scanning?

13.8.                          Hard Signs and Soft Signs

13.9.                          The Isolated Sign

13.10.                       Having Found a Chromosomal Sign …?

13.11.                       What Does the Knowledge of Karyotype Provide?

13.12.                       Trisomy 18 and Amniocentesis

13.13.                       Conclusion

14.              Management of the Fetus with CPC

14.1.                          A Comparison of the Ethical and Economic Implications of Suggested Protocols                

14.2.                          Three Suggested Protocols

14.3.                          Outcomes

14.4.                          Information Established in this Research

14.5.                          200 Cases of T18

14.6.                          Protocol 1 – Do Nothing

14.7.                          Protocol 2 – Amnio for all Fetuses with CPC (including Isolated CPC)

14.8.                          Protocol 3 – Amnio for Those with CPC and Other Abnormality(ies)

14.9.                          Which Protocol is More Effective?

14.10.                       Which Protocol Can be Ethically Justified?

14.11.                       Which Protocol is More Cost Effective

14.12.                       Conclusion

15.              Development of Pro-forma

15.1.                          Routine Scan Pro-forma

15.2.                          Chromosomal Marker Pro-forma

15.3.                          Conclusion

16.              Summary:                   

16.1.                          Conclusion

Appendices:                                                                                                               

                   1. Abbreviations                                                                                       

                   2. Glossary

                   3. Statistical methods

                   4. Maternal Age Modified Risks

                   5. Prevalence of T18                                                                                 

                   6. Proforma: 2nd and 3rd Trimester Worksheet                                        

                   7. Proforma: Chromosomal Markers Worksheet

                   8. ASUM Guidelines: 18-20 Week Obstetrical Scan                                 

Bibliography:                                                                                                            

Presentations Based On This Research