Moving forward with the echo intensity mean analysis: Exploring echo intensity bands in different age groups

Abstract

This study compared ultrasound characteristics in youth, younger adults, and older adults using two different methods of analysis: based on clusters of pixel concentration of the grayscale (i.e. EI bands) and the traditionally calculated echo intensity mean. Forty-four healthy youth (13.3±1.4 y), 22 younger adults (31.8±10.1 y) and 53 older adults (66.7±4.6 y) volunteered for the assessment of rectus femoris EI via ultrasonography. Pixel concentration (i.e. EI bands) was calculated in intervals of 0-50, 51-100, 101-150, 151-200, and 201-255 of the gray scale, while EI mean was determined as the average pixels from 0 to 255. EI0-50 significantly decreased with group age, while EI51-100, 101-150, 151-200, 201-255 and EI mean increased (P<0.001). The differences between groups were greater using EI0-50 compared to the EI mean (i.e. EI0-50: youth=~353% and younger adults=~251%>older adults; whereas EI mean: youth=~46% and younger adults=29%<older adults). These results potentially indicate that EI bands method offer different information than the EI mean method. In addition, EI bands may be a promising approach to understand tissue-specific adaptations to physical training and neuromuscular diseases, yet future studies should validate this method.