Evaluation of healthy and diseased muscle with magnetic resonance elastography
Evaluation of healthy and diseased muscle with magnetic resonance elastography
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DOI：
10.1053/apmr.2002.35472
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发表时间：
2002-11-01
影响因子：
4.3
通讯作者：
Kaufman, KR
中科院分区：
文献类型：
--
作者：
Basford, JR;Jenkyn, TR;Kaufman, KR
目的：为了研究一种新的组织成像技术，磁共振弹性成像（MRE），是否提供了一种可行的，非侵入性的方法来研究健康和患病的肌肉。设计：方便的样本。设置：磁共振成像（MRI）实验室。参与者：8名对照受试者（4名男性，4名女性），年龄在24至41岁之间，神经肌肉检查和病史正常，6名受试者（3男3女），年龄17 - 63岁，下肢神经肌肉功能障碍（1例儿童脊髓灰质炎，2例弛缓性瘫痪，3例痉挛性截瘫）。受试者仰卧，双腿置于1.5T MRI机器的线圈内，将他们的脚绑在踏板上，踏板定位成使得他们的脚踝的旋转轴线与装置重合。所有受试者均在空载（0扭矩）条件下进行测试。对照受试者也进行了评估，因为他们等距抵抗踝关节背侧（20.2Nm，40.5Nm）和足底（8.2Nm，16.4Nm）屈曲力矩。以相同的方式评价神经肌肉功能障碍受试者，但1名具有剩余下肢力量的受试者除外，该受试者只能在静息和被动踝关节背屈模式下进行测试。剪切波是由一个150赫兹的机电换能器位于腹部胫骨前。米泽图像是用梯度回波技术收集的，该技术与换能器的运动相关联。波相位传播可视化与8个相等的偏移图像在1 vibration-cycle.Main结果measurements：剪切波波长（λ）和肌肉刚度的变化（表示的剪切模量[G]）在胫骨前肌和gastrocnernius muscles.Results：波长和G组间不同，在所有的肌肉研究，并增加负荷的增加。此外，神经肌肉疾病组在休息时的λ和G（例：3.88 ± 0.48cm;范围：2.87-4.91cm; 38.40 ± 0.77kPa;范围22.35-59.67kPa）和腓肠肌外侧分别为，比对照组相同肌肉的1.5倍和2.4倍大（2.56+/-0.28cm，16.16 +/-00.19kPa; P=.0002）（1 Pa = 1 N/m（2））。结论：在健康肌肉中，剪切波波长和肌肉刚度随着负荷的增加而增加。此外，至少在我们的样本中，这些数量在有和没有神经肌肉疾病的肌肉之间存在显著差异。总之，MRE似乎提供了关于肌肉在休息时和收缩期间的机械特性的体内生理信息，这是不可用的。这项技术用于监测治疗和运动对健康和患病肌肉的影响的潜力值得进一步研究。
Objective: To investigate whether a new tissue-imaging technique, magnetic resonance elastography (MRE), offers a viable, noninvasive way to study healthy and diseased muscle.Design: Convenience sample.Setting: A magnetic resonance imaging (MRI) laboratory.Participants: Eight control subjects (4 men, 4 women), between the ages of 24 and 41 years, with normal neuromuscular examinations and histories, and 6 subjects (3 men, 3 women), ages 17 to 63 years, with lower-extremity neuromuscular dysfunction (1 with childhood poliomyelitis, 2 with flaccid, 3 with spastic paraplegia).Interventions: Subjects lay supine with their legs within the coils of a 1.5T MRI machine, with their feet strapped to a footplate positioned so that the axes of rotation of their ankles coincided with the apparatus. All subjects were tested in a no-load (0 torque) condition. Control subjects were also evaluated as they isometrically resisted ankle dorsi- (20.2Nm, 40.5Nm) and plantar- (8.2Nm, 16.4Nm) flexion moments. Subjects with neuromuscular dysfunction were evaluated in the same manner, except 1 individual with residual lower-extremity strength who could only be tested in the resting and passive ankle dorsiflexion modes. Shear waves were induced with a 150-Hz electromechanic transducer located over the belly tibialis anterior. MIZE images were collected with a gradient-echo technique gated to the transducer's motion. Wave-phase propagation was visualized with 8 equally offset images across 1 vibration-cycle.Main Outcome Measures: Changes in shear-wave wavelength (lambda) and muscle stiffness (as expressed by the shear modulus [G]) in the tibialis anterior and gastrocnernius muscles.Results: Wavelength and G differed between the groups in all the muscles studied, and increased as the load increased. Moreover, lambda and G in the neuromuscular disease group at rest (eg, 3.88+/-0.48cm; range, 2.87-4.91cm; 38.40+/-0.77kPa; range, 22.35-59.67kPa) and in the lateral gastrocnemius were, respectively, more than 1.5 and 2.4 times larger than they were in the same muscle in the control group (2.56+/-0.28cm, 16.16+/-00.19kPa; P=.0002) (1Pa=1N/m(2)).Conclusions: Shear-wave wavelength and muscle stiffness increased with load in healthy muscle. In addition, at least for our sample, these quantities differed significantly between muscles with and without neuromuscular disease. In summary, MRE appears to provide in vivo physiologic information about the mechanical properties of muscle at rest and during contraction that is not otherwise available. The potential of this technique for monitoring the effects of treatment and exercise on both healthy and diseased muscle merits further research.