The effect of aging on texture features of muscle ultrasound images

Abstract

Objective: Musculoskeletal ultrasound was used to acquire the muscle images of young and old people as well as measure the morphological differences of their muscles, associating with image processing to analyze the agerelated changes of muscle texture features. Method: Fifty healthy adult volunteers were recruited from May 2018 to July 2018, and divided into young group(<30 years, 22 cases) and elderly group(≥60 years, 28 cases) Musculoskeletal ultrasonography was used to acquire the transversal and longitudinal medial gastrocnemius ultrasonic images from two groups. Muscle thickness and pennation angle were measured directly. 9 region of interests(ROIs) was selected from each image mean and variance of gray level,contrast and homogeneity of the gray level co-occurrence matrix,entropy of the gray level of gray gradient co-occurrence matrix, gray level non-uniformity, run length non-uniformity, low gray-level run emphasis and high gray-level run emphasis based on the run length matrix were analysed for each ROI.. Result: In terms of muscle morphology, muscle thickness of the medial gastrocnemius significantly decreased in elderly group than the young one (P<0.05), and no significant difference was found in pennation angle between two groups (P>0.05). As for muscle texture, compared to the young group, variance, contrast, entropy, gray level non-uniformity and low gray-level run emphasis significantly decreased (P<0.05) while homogeneity and run length non-uniformity increased remarkably (P<0.05) in the elderly group. There was no significant difference between two groups in mean and high gray-level run emphasis (P>0.05). Conclusion: According to the assessment of muscle ultrasound images, older people had higher homogeneity and run length non-uniformity, lower variance, contrast, entropy, gray level non-uniformity and low gray-level run emphasis. Muscle ultrasonic image texture analysis can reflect the adverse changes of muscle structure with aging and may be used as a biomarker for studying the age-related muscle changes.