Hi there!
The signals are just radiological description on how the lesion appear in different modes, used to determine its characteristic. "posterior T10-T11 disc extrusion is present with superior extension of a 6 x 4 x 9 mm disc fragment" describes an intervertebral disc prolapse with extrusion of the disc material with upward extension. It would be best to discuss the situation and the suggested management plan in detail with your treating doctor.
Hope this helps.
Take care!