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.
Brain ; Calibration ; Eyeglasses ; Glass ; Head ; Head Movements ; Imidazoles ; Magnetic Resonance Imaging ; Magnetics ; Magnets ; Nitro Compounds ; Track and Field

Objective: Mental health problems such as anxiety, panic, and depression have been exacerbated by the coronavirus disease-2019 (COVID-19). This study aimed to compare the symptom severities and overall function before and during the COVID-19 pandemic among patients with panic disorder (PD) seeking treatment compared to healthy controls (HCs). Methods: Baseline data were collected from the two groups (patients with PD and HCs) in two separate periods: before COVID-19 (Jan 2016–Dec 2019) and during COVID-19 (Mar 2020–Jul 2022). A total 453 participants (before COVID-19: 246 [139 patients with PD and 107 HCs], during COVID-19: 207 [86 patients with PD and 121 HCs]) was included. Scales for panic and depressive symptoms and overall function were administered. Additionally, network analyses were performed to compare the two groups within the patients with PD. Results: The results of two-way analysis of variance analyses showed that patients with PD enrolled during COVID-19 showed higher levels of interoceptive fear and lower overall functioning. In addition, a network comparison test revealed that a significantly high strength and expected influence for agoraphobia and avoidance in patients with PD during COVID-19. Conclusion This study suggested that the overall function could have worsened, and the importance of agoraphobia and avoidance as a central symptom may have increased in patients with PD seeking treatment during COVID-19.