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Imaging and Quantification of the Hepatic Vasculature of Mice Using Ultrafast Doppler Ultrasound
Published on: July 19, 2024
In vivo imaging of blood flow in the mouse Achilles tendon using high-frequency ultrasound
Chih-Kuang Yeh1, Jia-Jiun Chen, Meng-Lin Li
1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC. ckyeh@mx.nthu.edu.tw
Objective:
Achilles tendinitis is a common clinical problem with many treatment modalities, including physical therapy, exercise and therapeutic ultrasound. However, evaluating the effects of current therapeutic modalities and studying the therapeutic mechanism(s) in vivo remains problematic. In this study, we attempted to observe the morphology and microcirculation changes in mouse Achilles tendons between pre- and post-treatment using high-frequency (25 MHz) ultrasound imaging. A secondary aim was to assess the potential of high-frequency ultrasound in exploring therapeutic mechanisms in small-animal models in vivo.
Methods:
A collagenase-induced mouse model of Achilles tendinitis was adopted, and 5 min treatment of continuous-mode low-frequency (45 kHz) ultrasound with 47 mW/cm(2) maximum intensity and 16.3 cm(2) effective beam radiating area was applied. The B-mode images showed no focal hypoechoic regions in normal Achilles tendons either pre- or post-treatment. The Doppler power energy and blood flow rate were measured within the peritendinous space of the Achilles tendon.
Conclusion:
An increase in the microcirculation was observed soon after the low-frequency ultrasound treatment, which was due to immediate induction of vascular dilatation. The results suggest that applying high-frequency Doppler imaging to small-animal models will be an invaluable aid in explorations of the therapeutic mechanism(s). Our future work includes using imaging to assess microcirculation changes in tendinitis between before and after treatment over a long time period, which is expected to yield useful physiological data for future human studies.
Insights
Low-frequency ultrasound treatment for Achilles tendinitis rapidly increased microcirculation via vascular dilation. High-frequency ultrasound imaging shows promise for studying therapeutic mechanisms in animal models.
Area of Science:
- Biomedical Engineering
- Musculoskeletal Research
- Diagnostic Imaging
Background:
- Achilles tendinitis is a prevalent clinical issue with various treatments.
- Evaluating therapeutic effects and mechanisms in vivo remains challenging.
- High-frequency ultrasound offers potential for in vivo assessment.
Purpose of the Study:
- To observe morphology and microcirculation changes in mouse Achilles tendons post-ultrasound treatment.
- To assess high-frequency ultrasound's utility in exploring therapeutic mechanisms in small-animal models.
Main Methods:
- A collagenase-induced Achilles tendinitis mouse model was used.
- Continuous-mode low-frequency ultrasound (45 kHz) was applied for 5 minutes.
- High-frequency (25 MHz) ultrasound imaging assessed morphology and Doppler assessed microcirculation.
Main Results:
- No focal hypoechoic regions were observed in normal tendons pre- or post-treatment.
- An immediate increase in microcirculation was noted post-treatment.
- This increase was attributed to immediate vascular dilatation.
Conclusions:
- Low-frequency ultrasound treatment induces rapid microcirculation changes in Achilles tendons.
- High-frequency Doppler imaging is valuable for studying therapeutic mechanisms in small-animal models.
- Future studies will use imaging for long-term microcirculation assessment in tendinitis.
