MRI Diagnosis and Classification of Brachial Plexus Injury

Purpose:To evaluate MR performance and application in diagnosis and classification of brachial plexus injury.Methods:Seventy cases of brachial plexus injury patients(operation was undertaken in 59 and followed - up exam without operation was done in 11) underwent MR scanning before operation.MR results were compared with the operation findings,electromyogram and following up results. Results:Of these 196 pairs of injured roots,MRI detected 176 pairs.The accuracy,sensitivity and specificity of MRI in diagnosing preganglionic brachial plexus injury were 89.1%,89.8%and 84.8%, respectively.The signs of preganglionic injury include:①lack or mutilation of nerve root,161 pairs;②coarsening,stiff and can not be traced to the intervertebral foramen continuously,20 pairs;③cystoid cerebrospinal fluid concentrating in vertebral canal,posttraumatic spinal meningocele,96 pairs;④abnormal shape of nerve sleeve,54 pairs;⑤displacement and deformity of spinal cord,79 segments;⑥fibrae scar in intervertebral foramen region,11 pairs;⑦spinal cord injury,5 patients;⑧abnormal signal of paraspinal muscles,42 patients.The signs of postganglionic injury include:①natural courser of the nerve,the same structure and signal intensity with normal side,2 cases;②thickening of the nerve,with continuity and natural courser,and increased intensity,18 cases;③thickening of the nerve,with continuity and stiff courser,19 cases;④losing of continuity completely,with isolated broken ends,2 cases;⑤traumatic nerofibroma,2 cases.The MRI performances of brachial plexus injury contained 6 subtypes: normal appearance,neural degeneration and edema,neural scarification and fibrosis,neurotmesis,root avulsion and the mixed type.Conclusion:MRI can help making a correct diagnosis in brachial plexus injuries,and is important for making treatment plan and improving the prognosis.