MRI diagnosis of brachial plexus preganglionic injury

Objective To evaluate MRI in diagnosing brachial plexus preganglionic injury.Methods Twenty cases with brachial plexus preganglionic injury underwent M R scanning before operation.MR imaging was obtained by GE Signa EXCITE 1.5 T scanner.The scanning sequences included SE T1 WI,FSE T2 WI,T2 WI STIR and 3D Fast imaging employing steady state with phase cycled(3D-FIESTA-c).All the patients had exploration of the supraclavicular plexus and electrophysiology examination. And the accuracy, sensitivity and specificity of MRI in diagnosing preganglionic brachial plexus iniury were calculated with the standards of surgical and EMG results.Results Among the 73 pairs of i,jured roots.MR imaging detected the abnormalities in 63 pairs.The accuracy, sensitivity and specificity of MRI in diagnosing preganglionic brachial plexus injury were 86.5/(83/96),86.3/(63/73).87.0/(20/23),respectively.The direct signs of brachial plexus preganglionic injury included (1) lack or mutilation of netwe root in 54 pairs (85.7/),(2)coarsening,bending,stiff course and unable to be traced to the intervertebral foramen continuously in 9 pairs (14.3/).The indirect signs included (1)cystic cerebrospinal fluid gathering in the vertebral canal,posttraumatic spinal meningocele in 46 pairs (73.0/),(2)abnormal shape of nerve sleeve in 13 pairs(20.6/),(3)displacement and deformity of spinal cord in 50 pairs(79.4/),(4)abnormal signal of paravertebral muscles in 1 9 patients.Conclusion MRI can distinctly show the nerve rootlets within the vertebral canal,so it is helpful in making a correct diagnosis of brachial plexus preganglionic injuries. Key words: Brachial plexus neuropathies; Diagnosis;  Magnetic resonance imaging