Anatomic characteristics and epidemiological investigation of shoulder injuries by training / 局解手术学杂志

Objective To investigate the epidemiological characteristics of shoulder injuries by training,and provide scientific evidence for effective intervention measures.Methods Through cluster random sampling method,a questionnaire survey was conducted on 1 080 trainers to analyze the occurrence of shoulder injury by training,the training courses lead to shoulder injuries and classification of shoulder injuries by training.The psychological status,shoulder symptoms,protective measures and other factors were compared between the injured group and the normal group to explore the influencing factors of injuries.Results Of 1 080 trainers,the incidence of shoulder injuries was 18.52％.The training course where injured were currently creeping forward (34.96％),push-ups (13.82％) and pull-ups (13.41％).The main types of injuries were soft tissue injuries(92.27％).The difference was statistically significant between two groups in the aspects of the mental state,shoulder protection measures and the presence of symptoms (P ＜ 0.01).Conclusion The shoulder injuries of training personnel were mainly caused by soft tissue injuries.Long time training,short time for rest,lack of control or confidence were the major risk factors.Shoulder symptoms during training and inadequate application of protective measures may lead to the incidence of training injuries increasing.

Head Motion Detection and Alarm System during MRI scanning

PURPOSE: During brain MRI scanning, subject's head motion can adversely affect MRI images. To minimize MR image distortion by head movement, we developed an optical tracking system to detect the 3-D movement of subjects. MATERIALS AND METHODS: The system consisted of 2 CCD cameras, two infrared illuminators, reflective sphere-type markers, and frame grabber with desktop PC. Using calibration which is the procedure to calculate intrinsic/extrinsic parameters of each camera and triangulation, the system was desiged to detect 3-D coordinates of subject's head movement. We evaluated the accuracy of 3-D position of reflective markers on both test board and the real MRI scans. RESULTS: The stereo system computed the 3-D position of markers accurately for the test board and for the subject with glasses with attached optical reflective marker, required to make regular head motion during MRI scanning. This head motion tracking didn't affect the resulting MR images even in the environment varying magnetic gradient and several RF pulses. CONCLUSION: This system has an advantage to detect subject's head motion in real-time. Using the developed system, MRI operator is able to determine whether he/she should stop or intervene in MRI acquisition to prevent more image distortions.

Effects of Motion Correction for Dynamic 11CRaclopride Brain PET Data on the Evaluation of Endogenous Dopamine Release in Striatum / 대한핵의학회잡지

PURPOSE: Neuroreceptor PET studies require 60-120 minutes to complete and head motion of the subject during the PET scan increases the uncertainty in measured activity. In this study, we investigated the effects of the data-driven head motion correction on the evaluation of endogenous dopamine release (DAR) in the striatum during the motor task which might have caused significant head motion artifact. MATERIALS AND METHODS: [11C]raclopride PET scans on 4 normal volunteers acquired with bolus plus constant infusion protocol were retrospectively analyzed. Following the 50 min resting period, the participants played a video game with a monetary reward for 40 min. Dynamic frames acquired during the equilibrium condition (pre-task: 30-50 min, task: 70-90 min, post-task: 110-120 min) were realigned to the first frame in pre-task condition. Intra-condition registrations between the frames were performed, and average image for each condition was created and registered to the pre-task image (inter-condition registration). Pre-task PET image was then co-registered to own MRI of each participant and transformation parameters were reapplied to the others. Volumes of interest (VOI) for dorsal putamen (PU) and caudate (CA), ventral striatum (VS), and cerebellum were defined on the MRI. Binding potential (BP) was measured and DAR was calculated as the percent change of BP during and after the task. SPM analyses on the BP parametric images were also performed to explore the regional difference in the effects of head motion on BP and DAR estimation. RESULTS: Changes in position and orientation of the striatum during the PET scans were observed before the head motion correction. BP values at pre-task condition were not changed significantly after the intra-condition registration. However, the BP values during and after the task and DAR were significantly changed after the correction. SPM analysis also showed that the extent and significance of the BP differences were significantly changed by the head motion correction and such changes were prominent in periphery of the striatum. CONCLUSION: The results suggest that misalignment of MRI-based VOI and the striatum in PET images and incorrect DAR estimation due to the head motion during the PET activation study were significant, but could be remedied by the data-driven head motion correction.