Selective reception of echoes generated within the body by nonlinear propagation describes:

Selective reception of echoes generated within the body by nonlinear propagation describes:

• A. Compound imaging
• B. Speckle reduction imaging
• C. 3D imaging
• D. Tissue harmonic imaging

Answer: (D)

This describes tissue harmonic imaging. As ultrasound travels through tissue, the wave becomes distorted because of nonlinear propagation, generating harmonic frequencies—most notably the second harmonic. The system is set to receive mainly these harmonics and to ignore the transmitted fundamental frequency. Because harmonic echoes originate inside the tissue and are less affected by near-field artifacts and side lobes, the resulting image has improved resolution and contrast, with fewer clutter artifacts. The other options involve different principles—compound imaging combines data from multiple angles, speckle reduction imaging applies processing to reduce graininess, and 3D imaging builds volumetric data—not the nonlinear generation and selective reception of tissue-generated harmonics.

This describes tissue harmonic imaging. As ultrasound travels through tissue, the wave becomes distorted because of nonlinear propagation, generating harmonic frequencies—most notably the second harmonic. The system is set to receive mainly these harmonics and to ignore the transmitted fundamental frequency. Because harmonic echoes originate inside the tissue and are less affected by near-field artifacts and side lobes, the resulting image has improved resolution and contrast, with fewer clutter artifacts. The other options involve different principles—compound imaging combines data from multiple angles, speckle reduction imaging applies processing to reduce graininess, and 3D imaging builds volumetric data—not the nonlinear generation and selective reception of tissue-generated harmonics.