Nonlinear contrast imaging with an array-based micro-ultrasound system.

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Preclinical Research

Background:

• Traditional contrast imaging above 15 MHz often uses B-mode subtraction, yielding insufficient contrast-to-tissue ratio (CTR).
• High-frequency ultrasound requires advanced techniques for effective small-animal imaging.

Purpose of the Study:

• To determine the optimal real-time nonlinear contrast imaging strategy for high-frequency small-animal ultrasound.
• To maximize contrast-to-tissue ratio (CTR) in the 18-24 MHz range using novel array-based systems.

Main Methods:

• Systematic investigation of pulse inversion and amplitude modulation for detecting nonlinear fundamental and subharmonic signals.
• In vitro and in vivo measurements to evaluate different nonlinear contrast imaging schemes.
• Generation of parametric images (peak enhancement, wash-in rate, rise time) using the optimal detection method.

Main Results:

• Nonlinear fundamental detection with amplitude modulation yielded optimal results.
• Achieved a 13 dB improvement in CTR compared to fundamental imaging.
• Successfully generated in vivo parametric images of murine kidneys reflecting blood perfusion kinetics.

Conclusions:

• Amplitude modulation combined with nonlinear fundamental detection is the optimal strategy for high-frequency small-animal ultrasound contrast imaging.
• Parametric imaging provides valuable insights into blood perfusion, aiding preclinical disease model studies.
• This technique is expected to enhance diagnosis and treatment assessment in diseases where perfusion is critical.