Petersilge C A, Pathria M N, Gentili A, Recht M P, Resnick D
Department of Radiology, University Hospitals of Cleveland, OH 44106, USA.
J Comput Assist Tomogr. 1995 Jul-Aug;19(4):596-600. doi: 10.1097/00004728-199507000-00017.
Denervation hypertrophy is an entity well recognized in the neurology literature, but with little mention in the radiology literature. Denervation hypertrophy occurs when a muscle paradoxically enlarges rather than atrophies in response to loss of innervation. The purpose of this report is to describe the MR appearance of true hypertrophy and pseudohypertrophy of muscle following denervation.
The clinical data and MRI findings in three patients with muscle enlargement due to denervation hypertrophy are reviewed retrospectively. Two women and one man aged 19-80 years were included. Denervation resulted from spinal stenosis in one patient, a herniated thoracic disc in another, and spina bifida with a tethered cord in the third.
True hypertrophy of a single muscle was seen in one patient and pseudohypertrophy of two muscles was present in one patient. One patient had one muscle with true hypertrophy and one muscle with pseudohypertrophy. Electromyographic examination was performed and was consistent with denervation in two patients. Biopsy confirmation of denervation was obtained in two patients. All five abnormal muscles exhibited increased volume, well defined margins, and normal contour. In true hypertrophy the enlarged muscle was isointense with normal muscle on all MRI sequences. In pseudohypertrophy the MRI appearance was consistent with an excessive amount of fat interspersed throughout normal muscle.
Magnetic resonance in these cases established muscle hypertrophy rather than neoplasm as the cause of a palpable mass. If muscle hypertrophy or pseudohypertrophy is seen on an MR examination of an enlarged extremity, the possibility of an underlying neurologic process should be considered.
去神经支配性肥大是神经学文献中已被充分认识的一种情况，但在放射学文献中提及较少。当肌肉对神经支配丧失做出反应时，反常地增大而非萎缩，就会发生去神经支配性肥大。本报告的目的是描述去神经支配后肌肉真性肥大和假性肥大的磁共振成像表现。
回顾性分析3例因去神经支配性肥大导致肌肉增大患者的临床资料和磁共振成像（MRI）表现。其中包括2名女性和1名男性，年龄在19至80岁之间。1例患者的去神经支配是由椎管狭窄引起，另1例是由胸椎间盘突出引起，第3例是由脊柱裂伴脊髓栓系引起。
1例患者出现单块肌肉的真性肥大，1例患者出现两块肌肉的假性肥大。1例患者有1块肌肉真性肥大和1块肌肉假性肥大。对2例患者进行了肌电图检查，结果与去神经支配相符。2例患者获得了去神经支配的活检证实。所有5块异常肌肉均表现为体积增大、边界清晰和轮廓正常。在真性肥大中，增大的肌肉在所有MRI序列上与正常肌肉等信号。在假性肥大中，MRI表现与正常肌肉中散在大量脂肪一致。
在这些病例中，磁共振成像确定肌肉肥大而非肿瘤是可触及肿块的原因。如果在对增大肢体的MR检查中发现肌肉肥大或假性肥大，应考虑潜在神经病变的可能性。
