【作者】 李锋；

【导师】 王仁法；

【作者基本信息】 华中科技大学 ， 影像医学与核医学， 2012， 博士

【摘要】 目的：利用双指数表观扩散系数观察肌肉运动后水分子的扩散及其恢复过程。方法：15名成年健康男性志愿者参加本研究,所有志愿者利用自制支架做定向足背屈运动直至肌肉疲劳。首先扫描胫骨前肌运动前后的T2WI和T2-mapping。志愿者休息48小时后同一时间段利用EPI-DWI序列进行胫骨前肌运动前和运动后3、6、9、12、15、18、21分钟multi-b DWI成像。b值采用0、20、50、100、200、300、400、500、600、700、800、900、1000、1100、1200共15个b值,按照双指数模型计算出fast ADC值和slow ADC值,按照单指数模型计算出standardADC值。根据fast ADC值、slow ADC值、standard ADC值和T2值绘制成相应的伪彩图及fast ADC值,slow ADC值和standard ADC值的恢复曲线。结果：静息状态下,胫骨前肌的T2值为46.04msec,肌肉运动后肌肉T2值.上升为59.93msec,上升幅度为30.2%(P<0.001)。静息状态下,胫骨前肌的standard ADC值为1.63×10-3mm2/S,fast ADC值为12.02×10-3mm2/S,slow ADC值为1.34×10-3mm2/S,静息时fast ADC值较slow ADC大。肌肉运动后,standard ADC值和slow ADC值均明显上升,分别达到2.04×10-3mm2/S,19.922×0-3mm2/S和1.65×10-3mm2/S,上升幅度为25%,65.8%和23.1%。经历21分钟恢复后,standardADC值仍然比静息状态高4.9%(P>0.05),fast ADC值,slow ADC值比静息状态高18.4%和9.0%(P<0.05,P<0.05)。其中fast ADC较standard ADC和slowADC恢复快。结论：肌肉运动后fast ADC和slow ADC变化的规律是由差别的,双指数表观扩散系数能够较好的观察运动后肌肉内的水分子扩散变化,反映出不同间隔水分子的扩散特征。目的利用MRI评价肌肉运动和冰敷后肌肉内的血流灌注及水分子扩散的变化。方法15名健康成年男性志愿者参加本研究,左右腿随机分配。所有志愿者利用自制支架做定向足背屈运动直至肌肉疲劳,首先进行肌肉运动前后T2WI、T2-mapping、DWI扫描以及30分钟自然恢复的T2W、T2-mapping、DWI扫描,接着进行肌肉运动前以及运动后3、6、9、12、15、18、21、24、27、30分钟FAIR扫描,最后肌肉疲劳收缩后30秒内开始冰敷小腿上段75%处,冰敷后FAIR时问点同运动后自然恢复FAIR扫描,FAIR扫描完成后,接着DWI序列扫描。结果静息时,胫骨前肌T2值为46.04±9.89mesc,肌肉运动后,T2值明显上升,达到59.93+8.97mese,较静息状态升幅为30.2%,具有统计学意义(P<0.001)。冰敷30分钟后与运动后30分钟恢复和静息状态下胫骨前肌的T2值没有统计学差异(分别t=0.81,P>0.05和t=0.77,P>0.05)。胫骨前肌运动后,ADC1和ADC2分别由2.29±0.32×10-3mm2/S,1.66±0.11X10-3mm2/S上升为3.72±0.41×10-3mm2/S,2.03±0.12×10-3mm2/S,上升幅度分别为62.4%和22.2%(P<0.001),30分钟恢复后,ADC1和ADC2均较静息状态高(P<0.05,P>0.05)。ADC1和ADC2和静息状态比分别下降了34.9%和27.7%(P<0.001)。胫骨前肌运动前灌注量104.68±6.47ml/min/100g,运动后灌注量明显上升,达到203.55±15.59ml／min/100g,上升幅度94.4%(P<0.001)。在自然恢复过程中,肌肉的血流灌注缓慢下降,至27分钟恢复至静息状态。冰敷对运动引起的肌肉灌注增加抑制明显,在6分钟内即下降68.4%,至18分钟时下降至静息状态。24分钟时又重新出现血流灌注增加,随后血流灌注继续下降。结论局部冰敷能够抑制运动引起的肌肉血流灌注增加,能明显降低肌肉内水分子的扩散。目的：探讨不同运动方式对小腿肌肉扩散张量参数的影响。方法：15名健康成年男性参与本研究,年龄范围25-36岁,平均29.88岁±4.12,BMI范围21.63-25.30平均23.03+1.47。利用SE-EPI序列进行小腿肌肉DTI成像,分别测量胫骨前肌,内侧腓肠肌于足中立位、背屈位、跖屈位以及主动收缩状态下的ADC、FA、λ1、λ2和λ3。结果：于足中立位时,两组肌肉3个本征值呈递减关系λ1>λ2>λ3,两组肌肉λ1没有统计学差异(P=0.38),GM的λ2、λ3、ADC要高于TA的λ2、λ3(分别P<0.05,P<0.01,P<0.01),GM的FA要低于TA的FA(P<0.05)。踝关节由跖屈转为背屈,TA被动收缩,FA值减少13.5%(P<0.005),ADC、λ2、λ3分别增加8.6%,12.4%,17.9%(分别P<0.001；P<0.001；P<0.001),λ1在两组没有统计学差异(t=0.96,P>0.05),踝关节由背屈转为跖屈时,GM被动收缩,FA值减少21.6%(P<0.005),ADC、λ2、λ3分别增加6.3%；10.5%和14.2%(分别P<0.001；P<0.05；P<0.001),λ1在两组没有统计学差异(t=0.94,P>0.05)。TA由中立位转为主动背屈时,ADCλ1、λ2、λ3分别增加11.4%、7.3%、11.0%、16.0%(P<0.001；P<0.001：P<0.005；P<0.001),FA下降17.1%(P<0.005)。GM由中立位转为主动跖屈时,ADC、λ1、λ2、λ3分别增加12.2%、6.3%、13.1%、16.8%(P<0.001；P<0.001；P<0.05；P<0.001)FA下降18.2%(P<0.001)。结论：本研究表明,肌肉主动运动和被动运动能够改变肌肉的弥散张量参数,这些参数的改变与肌肉的内部结构改变有关。更多还原

【Abstract】 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.更多还原