T Shiraishi1, T Chikui, K Yoshiura, K Yuasa. 1. Section of Image Diagnosis, Department of Diagnostics and General Care, Fukuoka Dental College, Tamura 2-15-1, Sawara-ku, Fukuoka 814-0193, Japan. ts0607@college.fdcnet.ac.jp
Abstract
OBJECTIVE: The aim of this study was to evaluate the changes in T2 values and apparent diffusion coefficient (ADC) in the masseter muscle by clenching in healthy volunteers. METHODS: 37 volunteers were enrolled in the study. We measured bite force using pressure-sensitive paper and a T2 map. The ADC map was obtained at rest, during clenching, immediately after and 5 min after clenching. The spin-echo sequence was used to calculate T2, and single-shot spin-echo echo planar imaging was used to calculate the ADC. The motion-probing gradients (MPGs) were applied separately along the posterior-to-anterior (PA), right-to-left (RL) and superior-to-inferior (SI) directions, with b values of 0, 300 and 600 s mm(-2) in each direction. ADC-PA, ADC-RL, and ADC-SI values were obtained, and we calculated the ADC-iso for the mean diffusivity. RESULTS: There were no significant differences between the stronger and weaker sides of bite force before, during or 5 min after clenching for T2 and ADC. The bite force had little effect on these parameters; thus, we used the average of the two sides for the following analyses. Time course analysis of ADC-iso, ADC-PA, ADC-RL and ADC-SI demonstrated a marked increase after clenching and a rapid decrease immediately after clenching, although they did not completely return to the initial values; however, the change in ADC-RL was significantly greater than those in ADC-PA or ADC-SI (P<0.001 each). The changes in T2 were similar to those of ADC, although not as marked. CONCLUSIONS: ADC (especially ADC-RL) was altered by contraction of the masseter muscle.
OBJECTIVE: The aim of this study was to evaluate the changes in T2 values and apparent diffusion coefficient (ADC) in the masseter muscle by clenching in healthy volunteers. METHODS: 37 volunteers were enrolled in the study. We measured bite force using pressure-sensitive paper and a T2 map. The ADC map was obtained at rest, during clenching, immediately after and 5 min after clenching. The spin-echo sequence was used to calculate T2, and single-shot spin-echo echo planar imaging was used to calculate the ADC. The motion-probing gradients (MPGs) were applied separately along the posterior-to-anterior (PA), right-to-left (RL) and superior-to-inferior (SI) directions, with b values of 0, 300 and 600 s mm(-2) in each direction. ADC-PA, ADC-RL, and ADC-SI values were obtained, and we calculated the ADC-iso for the mean diffusivity. RESULTS: There were no significant differences between the stronger and weaker sides of bite force before, during or 5 min after clenching for T2 and ADC. The bite force had little effect on these parameters; thus, we used the average of the two sides for the following analyses. Time course analysis of ADC-iso, ADC-PA, ADC-RL and ADC-SI demonstrated a marked increase after clenching and a rapid decrease immediately after clenching, although they did not completely return to the initial values; however, the change in ADC-RL was significantly greater than those in ADC-PA or ADC-SI (P<0.001 each). The changes in T2 were similar to those of ADC, although not as marked. CONCLUSIONS:ADC (especially ADC-RL) was altered by contraction of the masseter muscle.
Authors: B T Archer; J L Fleckenstein; L A Bertocci; R G Haller; B Barker; R W Parkey; R M Peshock Journal: J Magn Reson Imaging Date: 1992 Jul-Aug Impact factor: 4.813
Authors: Aritrick Chatterjee; Roger M Bourne; Shiyang Wang; Ajit Devaraj; Alexander J Gallan; Tatjana Antic; Gregory S Karczmar; Aytekin Oto Journal: Radiology Date: 2018-02-02 Impact factor: 11.105