Echo intensity obtained from ultrasonography images reflecting muscle strength in elderly men

Figures & data

Table 1 Physical characteristics, ultrasonography measurements, and muscle strength of the participants (n = 184)

Variables	Mean ± standard deviation	Range
Physical characteristics
Age (years)	74.4 ± 5.9	65.0–91.0
Height (cm)	163.2 ± 6.0	144.5–178.2
Weight (kg)	62.3 ± 9.5	33.4–89.6
Ultrasound measurements
FT (mm)	8.3 ± 2.4	2.8–15.4
MT (mm)	44.4 ± 6.9	26.9–59.1
EI	21.2 ± 4.9	12.1–34.0
Muscle strength (N • m)	118.9 ± 46.3	25.9–248.7

Abbreviations: EI, echo intensity; FT, subcutaneous fat thickness; MT, muscle thickness.

Figure 1 Typical examples of the high (left) and low (right) echo intensity of the rectus femoris muscle.

Note: The value of EI, defined as the mean pixel intensity in the muscle, was determined by gray scale analysis.

Abbreviations: EI, echo intensity; FT, subcutaneous fat thickness; MT, muscle thickness; RF, rectus femoris muscle; VI, vastus intermedius muscle.

Figure 2 Association between the EI value and isometric knee extension strength in all participants (n = 184).

Abbreviation: EI, echo intensity.

Table 2 Correlation coefficients between MT, EI, physical characteristics, and muscle strength of the participants (n = 184)

	MT	EI	Age	Height	Weight	FT	MS
MT	−	−0.102	−0.326**	0.224**	0.493**	0.071	0.411**
EI		−	0.280**	−0.063	−0.016	0.240**	−0.333**
Age			−	−0.327**	−0.308**	0.124	−0.451**
Height				−	0.541**	0.100	0.420**
Mass					−	0.395**	0.434**
FT						−	0.051
MS							−

Note:

** P < 0.01.

Abbreviations: EI, echo intensity; FT, subcutaneous fat thickness; MS, muscle strength; MT, muscle thickness.

Table 3 Association of EI and MT with muscle strength using multiple regression analysis (n = 184)

	β	P-value
EI	−0.294	<0.001
MT	0.381	<0.001

Note: MT and EI were used as explanatory variables for muscle strength.

Abbreviations: EI, echo intensity; MT, muscle thickness.

Table 4 Partial correlation coefficients between MT, EI, and muscle strength, with age, height, weight, and FT as control variables (n = 184)

	MT	EI	MS
MT	−	−0.052	0.213**
EI		−	−0.301**
MS			−

Note:

** P < 0.01.

Abbreviations: EI, echo intensity; FT, subcutaneous fat thickness; MS, muscle strength; MT, muscle thickness.