tailieunhanh - Ebook Neuroradiology companion - Methods, guidelines, and imaging fundamentals (5/E): Part 2

(BQ) Part 2 book “Neuroradiology companion - Methods, guidelines, and imaging fundamentals” has contents: Brachial plexus, congenital malformations, degenerative spine, infection inflammation, vascular disorders, neck masses, temporal bone, and other contents. | SECTION B IMAGING 974 SPINAL CHAPTER 20 Brachial Plexus Inflammatory and Infectious Plexitis Key Facts Viral and idiopathic plexitis: These are predominantly sensory and have an insidious onset. Most patients are between 30 and 70 years of age (uncommon in the very young). Most resolve spontaneously in 8 to 12 weeks after their onset. Other causes include: drug reaction (allergic), post viral (autoimmune), due to a vasculitis and a heredofamilial type. Main differential diagnosis: perineural tumor spread, post radiation changes, stretching injury, hypertrophic polyneuropathy, lymphoma, chronic inflammatory demyelinating polyneuropathy, thoracic outlet syndrome. Radiation-induced plexitis: Generally occurs with doses >6,000 cGy In the acute type, symptoms tend to be permanent (probably due to vascular injury and nerve ischemia) In the subacute type (onset generally at about 6 months after treatment), symptoms are transient and usually reversible. Most radiation-induced plexopathies are predominantly sensory. Diffuse thickening and enhancement of the brachial plexus may be indistinguishable from metastases and follow up is needed to rule out 975 progression, viral plexitis and chronic inflammatory demyelinating polyneuropathy may have a similar appearance. FIGURE 20-1. Coronal fat suppressed T2 shows thickening and increased signal in the roots and trunks of the left brachial plexus due to a herpes zoster infection. 976 FIGURE 20-2. Coronal fat suppressed T2, in a different patient, show diffuse thickening of the right plexus. The cause was never found but symptoms resolved with only supportive treatment. 977 FIGURE 20-3. Coronal fat suppressed T2 in a different patient with diffuse (presumably drug-induced) plexopathy shows diffuse thickening and increased signal in the brachial plexus .