66 year old woman with bilateral radicular symptoms and non-diagnostic lumbar MRI who did not improve after two decompressive lumbar spine surgeries.

(A) Anterior image plane demonstrated distal right S1 foraminal impingement with hyperintensity in the nerve root seen in A (*) and in B (**).

(B) Posterior image plane (3mm slices, no spacing) confirms hyperintensity in distal S1 root. The right proximal sciatic nerve is broadened and flattened at the sciatic notch with mild edema and increased caliber of fascicles. Her physical exam was consistent with a piriformis syndrome on the left only.