MR imaging of peripheral nervous system involvement: Parsonage-Turner syndrome.

A 55-year-old woman complained of right scapular pain, like burning, radiating down his right arm and numbness in the first three fingers of the hand. Neurologic examination showed a slight deficit of the right brachial triceps muscle. Neurophysiological assessment showed a mild involvement of the seventh right spinal root (C7). Conventional MR imaging of the cervical spine showed mild disc protrusion at level C5-C6 without spinal root compression. High resolution MR neurography with multiplanar reconstruction along the course of the right brachial plexus showed a mild increase in signal intensity and thickening of the C7 root, middle trunk and posterior cord, consistent with Parsonage-Turner Syndrome. STIR images showed increased signal intensity in the right infraspinatus muscle innervated by the suprascapular nerve. In our case, sensitivity and specificity of the new MR sequences are higher than the clinical and neurophysiological evaluations.