The Application Of Electrophysiological Examination Combined With MRI In Diagnosis Of Cubital Tunnel Syndrome

ObjectiveTo study the value of electrophysiological examination combined withmagnetic resonance imaging (MRI) in diagnosis of cubital tunnel syndrome(CuTS).MethodsWe examined30elbows of23patients with CuTS and15elbows of15controlsby electrophysiological examination and MRI. We detected the motorconduction velocity (MCV), cross sectional area (CSA) and relative signalintensity (RSI) of ulnar nerve across the elbow at the point of largest sizeproximal to the entrapment point (CSA1, RSI1) and the entrapment point(CSA2, RSI2). Then we calculated the ratio of CSA (CSAR=CSA1/CSA2) and theratio of RSI (RSIR=RSI1/RSI2). For comparing of MRI parameters at differentlevels and different groups, Independent-Samples T Test were applied. Explorecorrelation between MCV and CSA1, RSI1, CSAR, RSIR. The clinical andelectrophysiological diagnosis as the reference standard, a receiver operatingcharacteristic (ROC) curve was used to the MRI parameters.ResultsThe value of CSA1and RSI1was significantly greater than CSA2, RSI2inthe patient group (P<0.05). The value of CSA1, RSI1, CSARand RSIRwasobviously larger of patients than that of controls (P<0.05). MCV was negativelycorrelated with CSA1and CSARin the patient group (r=-0.62， r=-0.53). Therewere no correlation between MCV and RSI1, RSIRin the patient group. The areaunder ROC curve of CSARwas the largest0.94(95%CI,0.83-1). The optimumcutoff point of CSARwas1.83. The CSARhad sensitivity of93.3%and specificity of80%in diagnosis of CuTS.ConclusionThe electrophysiological examination combined with MRI shows a highaccuracy of locating the entrapment point of ulnar never lesion at the elbow. Theincreasing CSARof ulnar nerve is the best MRI parameters in diagnosis ofCuTS.