Understanding Ultrasound Display Modes

Nov 7, 2024

Unit 11: Modes in Ultrasound

Introduction to Modes

  • Ultrasound display modes interpret and display ultrasound information.
  • Three display modes discussed:
    • Amplitude Mode (A Mode)
    • Brightness Mode (B Mode)
    • Motion Mode (M Mode)
  • Understanding each mode requires knowledge of axis variables.

Section 11.1: A Mode (Amplitude Mode)

  • Purpose: Displays strength of returning echo.
  • Appearance: Spike-like graph.
    • Tall spikes: Strong reflectors.
    • Short spikes: Weak reflectors.
    • Flatline: No reflectors.
  • Uses: Primarily in ophthalmology to map eye structures.
  • Graph Interpretation:
    • X-axis: Time of flight/depth.
    • Y-axis: Amplitude.
  • Analogy: Resembles a city skyline.

Section 11.2: B Mode (Brightness Mode)

  • Purpose: Produces grayscale diagnostic images.
  • Image Composition:
    • Made of scan lines, represented by pixels.
    • Original B-mode: Pixels on (white) or off (black).
    • Current systems: Variety of grays.
  • Graph Interpretation:
    • X-axis: Depth from transducer.
    • Z-axis: Brightness, mapped from amplitude using an oscilloscope.
  • Note: Depth and brightness intrinsic to understanding.

Section 11.3: M Mode (Motion Mode)

  • Purpose: Graphs motion of anatomy over time; useful in cardiac, fetal, and emergency evaluations.
  • Graph Composition:
    • One scan line, mapping motion quickly.
    • PRF (Pulse Repetition Frequency) determines sampling rate.
  • Graph Interpretation:
    • Y-axis: Depth.
    • X-axis: Time.
    • Horizontal Lines: No motion.
    • Squiggly Lines: Presence of motion.
  • Applications:
    • Cardiac: Evaluates ventricle size and movement.
    • OBGYN: Measures fetal heart rate.

Summary

  • Recognize mode by image and axis representation:
    • A Mode: Amplitude (Y-axis), Depth (X-axis).
    • B Mode: Depth (X-axis), Brightness (Z-axis).
    • M Mode: Depth (Y-axis), Time (X-axis).
  • Complete activities and review questions in the workbook for self-assessment.