Dynamic morphometric characterization of local connective tissue network structure in humans using ultrasound

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Tissue Mechanics

Background:

• Connective tissue forms a complex network with potential mechanosensory, regulatory, and signaling functions.
• Non-invasive measurement of collagen network structure in vivo is crucial for understanding these functions.
• Current methods lack the ability to quantify dynamic changes in connective tissue structure in live subjects.

Purpose of the Study:

• To demonstrate that ultrasound can quantify dynamic changes in local connective tissue structure in vivo.
• To correlate ultrasound imaging with histological findings of collagen structure.
• To assess tissue response to mechanical perturbation using ultrasound.

Main Methods:

• Combined 3-D ultrasound and histology examinations in surgical subjects.
• Robotic acupuncture needling to induce localized tissue perturbation.
• Ultrasound elastography and semi-variogram analyses to quantify spatial organization and dynamic changes in non-surgical subjects.

Main Results:

• 3-D ultrasound images revealed structures consistent with histological collagen sheets.
• High correlations (r=0.79 and r=0.63) between ultrasound and histology confirmed spatial structure concordance.
• Needle rotation induced significant tissue displacement and changes in tissue structure, with 10-fold greater variability compared to no rotation.

Conclusions:

• Ultrasound combined with semi-variogram analysis provides a quantitative method for assessing in vivo dynamic changes in human connective tissue structure.
• This approach enables non-invasive monitoring of connective tissue remodeling and response to mechanical stimuli.
• The findings support the use of ultrasound for in vivo studies of connective tissue biomechanics.