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Basic Obstetric Ultrasound Training #2

May 29, 2024

Basic Obstetric Ultrasound Training Course for Healthcare Providers

Course Overview

  • Purpose: Train healthcare workers to perform basic pregnancy ultrasound in low-resource settings.
  • Resources: Videos and educational materials available at tinyurl.com/uwultrasound.
  • Duration: Designed for a two-week course.
  • Practical Component: Hands-on sessions supervised by experienced practitioners.
  • Certification: No official certification or diploma.
  • Post-Course Recommendation: 40 hours of supervised scanning experience.

Course Introduction

  • Narrator: Dr. Christina Adams Waldorf.
  • Focus: How ultrasound works and how to operate the ultrasound machine.
  • Main Questions: Image production, structure identification (fetal organs, fluid, bones), image enhancement, and safety of ultrasound.

Basics of Ultrasound

  • Sound Waves: Vibrations traveling through the air; high-frequency sound waves are inaudible to humans.
  • Transducer Function: Produces high-frequency sound waves, sends them into the body, and receives reflected echoes.
  • Image Formation: Computer analyzes reflections (echoes) to create images.

Interpreting Ultrasound Images

  • Shades of Gray: Different tissues/fluid reflect sound waves differently.
    • Fluids: No echoes (black).
    • Bones/Air: Strong echoes (white).
    • Soft Tissues: Intermediate echoes (shades of gray).
  • Key Terms:
    • Echogenicity: Brightness/whiteness of echoes.
    • Hyperechoic: Very strong echoes (white/light gray).
    • Anechoic: No echoes (black).
    • Isoechoic/Hypoechoic: Varying shades of gray.

Types of Tissue on Ultrasound

  • Cystic Tissue: Fluid-filled, anechoic (black).
  • Solid Tissue: No fluid, reflects some echoes (gray/white).
  • Complex Tissue: Both cystic and solid elements.

Key Controls on Ultrasound Machine

  1. Overall Gain: Enhances echoes for clearer structures; too low or too high can distort images.
  2. Time Gain Compensation (TGC): Adjusts gain at different depths for finer control of image quality.
  3. Depth: Controls how deep sound waves penetrate; images should center on the target structure.
  4. Zoom: Magnifies target for detailed view.
  5. Focus: Improves resolution of target area; essential for detailed images.

Safety of Ultrasound

  • ALARA Principle: As Low As Reasonably Achievable; scan only for medical reasons and limit exposure.
  • Risk Mitigation: Decrease machine output and scanning time, especially critical in the first trimester.

Summary of Key Points

  • Image Production: Sound waves create images by reflecting off different tissues.
  • Echogenicity Levels: Range from hyperechoic to anechoic.
  • Tissue Types: Cystic, solid, complex.
  • Machine Controls: Overall gain, TGC, depth, zoom, focus.
  • Safety: Follow the ALARA principle to ensure patient safety.

Review Questions

  1. What happens to ultrasound waves when they reach air or bone? - They are reflected.
  2. What does fluid look like on ultrasound? - It appears black.
  3. What are the three main types of tissue? - Complex, cystic, and solid.
  4. What are the five important buttons on the ultrasound machine? - Gain, TGC, depth, zoom, and focus.
  5. What is the ALARA principle? - Scan only when medically necessary and limit exposure.

Acknowledgements

  • Contributors: Dr. Robert Nathan, Dr. William Marks, Nicole Goldsmith, and others.
  • Funding: GE Foundation, Consano, University of Washington departments.
  • Contact Information: For course questions, contact Dr. Robert Nathan, Dr. William Marks, or Dr. Christina Adams Waldorf.

Website: Visit tinyurl.com/uwultrasound for all training materials.

  • Copyright: Material can be copied, distributed, posted, and modified with attribution to University of Washington.

Full transcript