Practice Test GeeksARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test
← All ARDMS SPI Flashcard Decks

Attenuation, Reflection, and Refraction Flashcards

7 cards from real ARDMS SPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Attenuation, Reflection, and Refraction flashcards as text

  1. A sonographer tilts the transducer away from perpendicular when scanning a tendon. What effect does this have on the echogenicity of the tendon?

    Answer: The tendon appears hypoechoic due to anisotropy

    Tendons exhibit anisotropy; off-axis imaging reduces specular reflection from their parallel fibers, making them appear hypoechoic.

  2. Critical angle refraction in ultrasound occurs when:

    Answer: The refracted beam travels parallel to the interface (90° refraction)

    At the critical angle, refraction bends the transmitted beam to 90°, meaning it travels along the interface and no energy enters medium 2.

  3. What is the primary mechanism of attenuation in blood?

    Answer: Scattering by red blood cells

    Red blood cells act as Rayleigh scatterers, and scattering is the dominant mechanism of attenuation in blood.

  4. A mirror-image artifact occurs because of:

    Answer: Strong specular reflection at a curved or flat interface causing double registration

    A strong specular reflector (e.g., diaphragm) re-reflects echoes back to a structure, causing its mirror image to appear on the other side.

  5. How does the presence of a gas bubble affect ultrasound beam propagation?

    Answer: It causes near-total reflection and distal shadowing

    Gas has very low acoustic impedance, creating an extreme mismatch with tissue that reflects almost all incident energy and shadows structures behind it.

  6. What happens to wavelength as ultrasound travels from soft tissue into bone?

    Answer: Wavelength increases because propagation speed is higher in bone

    Bone has a higher propagation speed (~4080 m/s) than soft tissue; since frequency is constant, wavelength = c/f increases.

  7. Which imaging scenario is MOST likely to produce a refraction artifact causing a false double image of a structure?

    Answer: Scanning through the rectus abdominis muscle edge into deeper tissue

    The curved edge of the rectus abdominis acts as a refracting lens, splitting the beam and creating a duplicated image of deeper structures.