Table 2.

Spearman correlations between quantitative backscatter analysis (QBA) and grayscale level (GSL) with age and NSAA measured from superficial regions of muscle in DMD and control subjects.

Muscle	Age				NSAA
	DMD (n=25)		Control (n=25)		DMD (n=14)
	QBA	GSL	QBA	GSL	QBA	GSL
Deltoid	0.70***	0.63***	0.097	0.030	−0.36	−0.33
Biceps Brachii	0.54**	0.38	0.17	0.050	−0.20	−0.28
Wrist/Finger Flexors	0.58**	0.53**	−0.20	−0.320	−0.19	−0.18
Quadriceps	0.014	0.20	0.0030	0.059	−0.31	−0.17
Tibialis Anterior	0.45*	0.40*	0.14	0.15	−0.76**	−0.68**
Gastrocnemius	0.11	0.058	−0.11	−0.20	−0.27	−0.44
Six Muscle Average	0.67***	0.47*	−0.0020	−0.085	−0.59*	−0.60*

^*P<0.05,

^**P<0.01,

^***P<0.001;

DMD: Duchenne Muscular Dystrophy, NSAA: North Star Ambulatory Assessment, QBA: quantitative backscatter analysis; GSL: Grayscale level