Sensitivity Enhancement Using Chirp Transmission for an Ultrasound Arthroscopic Probe.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Orthopedics

Background:

• Meniscal tears are common knee injuries often treated with meniscectomy.
• Accurate assessment of meniscus vascularization is crucial for predicting healing capacity after surgery.
• Current arthroscopic methods lack the sensitivity to precisely measure low blood flow in the meniscus.

Purpose of the Study:

• To develop and evaluate an ultrasound-based method for estimating meniscus vascularization density during arthroscopic surgery.
• To enhance the sensitivity of ultrasound imaging for detecting slow blood flow within the meniscus.

Main Methods:

• An arthroscopic ultrasound probe utilizing ultrafast sequences was developed.
• A chirp-coded excitation combined with a mismatched compression filter was employed to improve signal-to-noise ratio (SNR).
• The proposed method was compared against standard ultrafast and Hadamard-coded emissions, and mismatched versus matched filters using a flow phantom.

Main Results:

• The chirp-coded excitation with a mismatched filter demonstrated a 4.4-10.4 dB SNR increase over Hadamard emission for slow flow velocities (mm/s).
• Compared to a matched filter, the mismatched filter provided a 3.1-6.6 dB SNR increase.
• This improvement in SNR was achieved with a minor 13% loss in axial resolution.

Conclusions:

• The proposed ultrasound method significantly enhances the detection of slow blood flow in the meniscus.
• The chirp-coded excitation and mismatched filter offer a promising approach for ultrasensitive vascularization assessment in arthroscopic surgery.
• This technology represents a crucial step towards an ultrasensitive ultrasound arthroscopic probe to assist surgeons in meniscectomy procedures.