Total energy of image

I am working on a 2 groups of patients with different therapies in brain cancer. I carried out T2 MRI texture analysis for different ROI. In selected 10 features for heterogeneity (uniformity, TE, entropy, variance, kurtosis, cluster shade, Difference variance, difference entropy, correlation etc), I found only Total Energy ( TE) to be showing significant difference between two groups and no other feature shows significant difference when these groups are compares.
Besides in other larger group I found TE to the only consistent feature found to be correlated with the dose while others do not show this consistent findings.
Can someone help me to interpret these results.

Is this significant or by chance? What total energy represents?
Thanking You.
Kind Regards