Fig. 1.

A,B: Sagittal T1-weighted MR images. A. Normal patient image for comparison; B. Patient image. The image of our patient (B) reveals a thick layer of abundant subcutaneous fat (*) and a thick proliferation of epidural fat (arrows) compressing and displacing the dural sac toward the anterior. Observe on the normal image (A) that both subcutaneous fat and epidural fat are less abundant and cause no compression or displacement of the dural sac.

C,D: Axial T1-weighted MR images. C. Normal patient image for comparison; D. Patient image. Image C of a normal patient shows a very thin rim of epidural fat surrounding the circular shaped dural sac with no evidence of compression. The axial image of our patient (B) shows dramatic proliferation of epidural fat (arrows) compressing the dural sac into a trefoil shape to approximately 25% of its normal size. Note also the abundance of subcutatneous fat (*) in our patient compared to the normal patient.