| Objective:The purpose of this study was to investigate the water exchange of the exercised skeletal muscle on the basis of multi-component diffusion weighted imaging.Methods:In this study, we assessed the physiological changes after exercising skeletal muscle on the basis of multi-component diffusion weighted imaging. Fifth health young men were asked to confirmed informed written consent and under weighted MRI of the calf muscles. An EPI-DWI and FSE imaging sequence were the used to acquire multi-component diffusion weighted imaging and T2-mapping imaging. The EPI-DWI imaging sequence was repeated at3,6,9,12,15,18and21min. The acquired signal decay curves were fit both mono-exponential and bi-exponential signal decay functions. The diffusion encoding gradient used15b values from0to1200s/mm2(b=0,20,50,100,200,300,400,500,600,700,800,900,1000,1100and1200).Results:the T2value of anterior tibialis increased from46.04msec at rest to59.53msec after excises, the rising rate was30.2(P0.001). The values of standard ADC, fas tADC, and slow ADC increased from1.64×10-3mm2/S,12.02×10-3mm2/S, and1.34×10-3mm2/S to2.04×10-3mm2/S,19.92×10-3mm2/S, and1.65x00-3mm2/S, respectively. The rising rates were25%,65.8%and23.1%, respectively (P<0.001, P<0.05, P<0.05). The rising magnitude of fast ADC was the most obvious. When recovering in the21min, the values of standard ADC of recovery was higher than rest (P>0.05), fast ADC, and slow ADC were still high (P<0.05and P<0.05). The recovery speed of fast ADC was faster than the others.Conclusion:Bi-exponential apparent diffusion coefficient can provide more detail information about water exchange in exercised skeletal muscles. Purpose:To study the suppressive effect of local cooling on the perfusion and water diffusion in the exercised muscles.Methods:Fifteen health young men were asked to confirmed informed written consent and under weighted MRI of the calf muscles. The scan sequence included T2WI, T2-mapping, DWI and FAIR. At first, T2WI, T2-mapping and DWI were obtained before and after exercise immediately and30min recovery after exercise. And then the fair were obtained before exercise and up to30min post exercise at3min intervals. At last, the cool bag was placed on the upper anterior tibialis after exercise in the30s. The methods of scan were same to the front.Results:the T2value of the anterior tibialis increased from46.04±9.89mesc at rest to59.93±8.97mese after exercise. The rising rates were30.2%(P0.001). The T2values returned to the pre-exercise values after30min cooling and30min recovery period, and were no significant differences between them. After exercise, both ADC1and ADC2increased from2.29±0.32×10-3mm2/S to3.72±.41×10-3mm2/S and1.66±0.11×10-3mm2/S to2.03±0.12×10"3mm2/S, respectively. The rising rates were62.4%and22.2%, respectively. After30min recovery, both ADC1and ADC2remained higher (P<0.01, P>0.05). Conversely, after cooling, both ADC1and ADC2decreased significantly, the rates of decline were34.9%and27.7%(P<0.001). With regard to FAIR, the perfusion of anterior tibialis increased from104.68±6.47ml/min/100g to203.55±15.59ml/min/100g, the rising rate was94.4%. In the30min recovery period, the perfusion decreased gradually, and returned to pre-exercise value at27min. while when applied to cooling, the perfusion decrease apprenently and returned to baseline pre-exercise value at18min. the perfusion reelevated at24min.Conclusion:the local cooling can suppress the perfusion elevation and decrease the water molecules diffusion induced by exercise in the calf Purpose:to assess the alteration diffusion parameters Associated With different movements of foot.Methods:In this study, we assessed the alteration diffusion parameters of calf muscles after different movement of ankle. Fifteen health young men were asked to confirmed informed written consent and under weighted MRI of the calf muscles. An EPI-DWI sequence was the used to acquire diffusion tensor imaging. The EPI-DWI imaging sequence was repeated during active and passive dorsal flexion and plantar flexion of the foot. The ADC, FA,,λ1,\2and λ3were calculated.Results:At rest, in both muscles, the relatives of the three eigenvalues is λ1>>2>λ3, the e2, λ3and ADC is higher in GM than in TA (P<0.05, P<0.01, P<0.01, respectively). When the ankle was converted from passive planaflexion to passive dorsal flexion, the ADC, X2and d,3of TA increased8.6%,12.4%and17.9%(P<0.00, P<0.001, P<0.001, respectively), the FA decreased13.5%(P<0.005). when the ankle was converted from passive dorsal flexion to passive planaflexion, ADC, λ2and d3of GM increased6.3%,10.5%and14.2%(P<0.001, P<0.05and P<0.001,respectively), FA decreased21.6%. No changes were founded in the both muscles when they were passive movement. When active contraction, ADC,,λ,,,2and λ3of TA increased11.4%,7.3%,11.0%and16.0%(P<0.001; P<0.001; P<0.005; P<0.001, respectively), FA of TA decreased17.1%(P <0.005). while ADC, X,,1,2andλ3of GM increase12.2%,6.3%,13.1%,16.8%(P<0.001; P<0.001; P<0.05; P<0.001, respectively), FA of GM decreased18.2%(P<0.001) Conclusion:the diffusion tensor imaging can reflect the distinct diffusion parameters of the human calf muscles by the movement of foot. The alterations are associated with the change of the muscles structures by the movement of foot.
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