Basic physics and imaging characteristics of ultrasound

Area of Science:

• Medical Imaging
• Biophysics

Background:

• Diagnostic ultrasound (US) imaging quality depends on tissue ultrasonic properties, primarily propagation velocity and attenuation.
• These properties dictate imaging frequency, influencing axial and lateral resolution limits.
• US equipment assumes straight-line, narrow beam propagation, which is an oversimplification.

Purpose of the Study:

• To explain how tissue properties affect diagnostic ultrasound imaging.
• To highlight the causes and implications of artifacts in ultrasound imaging.
• To provide guidelines for accurate interpretation of ultrasound images.

Main Methods:

• Analysis of ultrasonic wave propagation in biological tissues.
• Identification of factors causing deviation from idealized beam behavior.
• Review of principles leading to artifact formation in ultrasound imaging.

Main Results:

• Tissue's ultrasonic properties (velocity, attenuation) fundamentally limit resolution and imaging frequency.
• Variations in tissue propagation velocity cause beam deviation, challenging imaging assumptions.
• Non-ideal beam propagation and tissue interactions generate artifacts impacting image interpretation.

Conclusions:

• Accurate interpretation of diagnostic ultrasound images requires understanding tissue-dependent wave propagation.
• Appreciation of artifacts arising from deviations in US beam behavior is essential.
• Skilled interpretation involves critical evaluation of displayed and non-displayed features across multiple images.