Correlation Between Neural EMG、ultrasonic And MRI In The Carpal Tunnel Syndrome

Research purpose: to discuss the application of neural EMG examination, ultrasonic examination and MRI examination in the carpal tunnel syndrome(CTS) and their correlation through the neural EMG examination, ultrasonic examination and MRI examination of CTS patients.Research content: conduct neural EMG examination, ultrasonic examination and MRI examination of 36 CTS patients and 40 healthy controls and then compare the examination results. The intermediate and late CTS patients undergo surgery and the pathological changes of median nerve found during surgery are compared with the examination results of preopreative ultrasonic and MRI examination.Research method: use KEYPOINT 4 four-pillar EMG evoked ppotentiometer for examination of patients and volunteers, including EMG examination and ENoG examination. First, use concentric needle to check the abductor pollicis brevis muscle and observe whether there is delay of insertion potential and spontaneous potential under the quiescent condition; time limit and amplitude of potential of single motor unit upon small muscle contraction; type and peak-peak value of recruitment potential upon strong muscle contraction. Then, conduct median nerve conduction examination and the parameters measured include motor nerve conduction velocity, distal motor latency, sensory nerve conduction velocity and sensory nerve action potential amplitude. Next, divide CTS into early、intermediate and late three stages according to the electrophysiological staging diagnostic criteria. Use Logiq E9 color Doppler ultrasonography of GE for the examination of three stages CTS patients and volunteers: conduct longitudinal scan of carpal canal and median nerve with ultrasonic probe and observe the location, trend of median nerve in the carpal canal, changes of anteroposterior diameter of median nerve and compressed nerve part from the sagittal view; then, conduct horizontal scan of carpal canal with ultrasonic probe, and measure and record the cross-sectional area(CSA) of median nerve of pisiform bone. Finally, use 750 3.0T MR imager of GE for the examination of three stages CTS patients and volunteers, with T1 weighted imaging and short-switching time restoration T2 WI sequence, measure the parameters of carpal canal: median nerve swelling rate(MNSR) and median nerve flatness ratio(MNFR) and compare the examination results. The intermediate and late CTS patients undergo surgery and the pathological changes of median nerve found during surgery are compared with the examination results of preopreative ultrasonic and MRI examination.Research result: for early CTS patients, CSA, MNSR and MNFR have no obvious change compared with the control group. However, for intermediate and late CTS patients, CSA, MNSR and MNFR increase and the difference is of statistical significance compared with the control group(P<0.05). Neural EMG is related to ultrasonic examination and MRI examination, that is, the distal motor latency of median nerve increases obviously, the sensory nerve conduction velocity is obviously slower, the median nerve is thicker and thicker and CSA, MNSR and MNFR increase obviously; however,there was no correlation between the distal motor latency and CSA,no correlation between the sensory nerve conduction velocity of median nerve and MNFR.It is verified by surgery that the compression part of most median nerve is the hamate bone and the median nerve of pisiform bone has different degree of thickening and swelling, which are consistent with the preoperative ultrasonic examination and MRI examination results.Research conclusion: neural EMG examination can provide basis and the best treatment time for the early diagnosis of CTS. For intermediate and late CTS patients, ultrasonic examination and MRI examination can make a diagnosis of the severity of CTS; they can also identify the compression part and reason of median nerve of carpal canal and provide more morphological information before operation, which are important to the determination of operation plan. Therefore, ultrasonic examination and MRI examination are valuable examination methods for CTS. However, for the diagnosis of CTS, ultrasonic examination and MRI examination cannot replace neural EMG examination.