Is a traumatic injury visible?
It is difficult to be certain but there appears to be a subtle contour abnormality to the anterior cortex to T8 suggesting a minor compression fracture.
What incidental finding is present?
A low attenuating mass in the canal, posterior to the cord.
What density is this mass (i.e what is it composed of)? How does one confirm this on CT?
The mass is of similar density to subcutaneous fat. This can be confirmed by performing a region of interest measurement (ROI), which will give a value of approx -90HU.
What is the differential diagnosis for the mass? Why?
As the mass contains fat, it limits the differential essentially to a lipoma or a dermoid cyst.
Sagittal bone and axial soft tissue images demonstrate a mass with fat density posterior to the cord, appearing extramedullary but intradural.
The T8 vertebral body has a subtle cortical contour abnormality.