Interleave-sampled photoacoustic imaging: a doubled and equivalent sampling rate for high-frequency imaging

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Acoustic Physics

Background:

• High-frequency photoacoustic (PA) imaging demands high sampling rates for data acquisition (DAQ), posing hardware challenges and increasing costs.
• Existing DAQ systems struggle to meet the high sampling rate requirements for effective high-frequency PA imaging.

Purpose of the Study:

• To introduce and validate a novel interleaved-sampled PA imaging method.
• To demonstrate the capability of achieving high-frequency PA imaging with reduced sampling rates.

Main Methods:

• Developed an interleaved-sampled PA imaging technique utilizing two low sampling rate acquisitions to effectively double the sampling rate.
• Modulated light pulse delays, making the method compatible with existing PA DAQ systems.
• Conducted phantom and in vivo studies using a 30-MHz transducer and a 41.67-MHz sampling rate.

Main Results:

• Interleaved sampling at 41.67 MHz successfully captured high-frequency information (>30 MHz), unlike conventional sampling at the same rate.
• Achieved superior axial resolution of 63 µm and lateral resolution of 91 µm with interleaved sampling.
• Conventional 41.67-MHz sampling resulted in lower resolutions (130 µm axial, 136 µm lateral).

Conclusions:

• Interleaved-sampled PA imaging is a viable method for high-frequency ultrasound imaging.
• This technique overcomes hardware limitations and cost barriers associated with high sampling rates.
• The method significantly enhances image resolution compared to conventional sampling techniques.