Magnetic resonance imaging of denervated muscle: Comparison to electromyography

Abstract

The purpose of the study is to further assess the usefulness of short TI (time to inversion) recovery (STIR) magnetic resonance imaging (MRI) in detecting denervation of skeletal muscle compared to needle electromyography (EMG). Ninety subjects with clinical evidence of peripheral nerve injury or radiculopathy underwent STIR MRI and EMG of the affected limb. In 74 (82%) of these subjects, a positive correlation was found between STIR MRI and EMG (P < 0.009). STIR MRI has a relative sensitivity of 84% and specificity of 100% for detecting denervation. A subset of 28 subjects underwent quantitative assessments of signal intensity ratio (SIR) from the STIR MRI. The rank order correlation coefficient between the SIR and abnormal spontaneous activity on EMG was 0.70 (P < 0.001). Increased signal intensity on STIR MRI corresponds closely with spontaneous activity on EMG in denervated muscle. Although less sensitive than EMG in detecting muscle denervation, STIR MRI may be a useful adjunctive diagnostic tool in this setting. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 1431‐1434, 2000

The Pearls and Pitfalls of Magnetic Resonance Imaging for the Spine

“…1,35,37,38,40,62 In fact, innovative uses for advanced MRI applications may become particularly helpful in assessing the structure and function of spinal tissues (eg, muscles and intervertebral discs) and their physiological response to commonly prescribed physical therapy techniques. 16,23,31,32,38,46,70 These will be discussed in more detail in the cervical, thoracic, and lumbar spine sections.…”

“…25,46,70 Such information may be helpful in determining prognosis and response, or lack thereof, to conservative treatment. 25,40,46 Despite these technological advances, the current economic costs associated with MRI may preclude the referral for, and performance of, serial MRI in current physical therapy clinical practice.…”

The clinical presentation of chronic whiplash and the relationship to findings of MRI fatty infiltrates in the cervical extensor musculature: a preliminary investigation

“…However, the direction of the association between PPT_local, TF (P = 0.09) and TUF (P = 0.1) was inverse (e.g., those with higher fat content had higher thresholds) and this is more difficult to explain. Nevertheless, the results of this study might provide some preliminary evidence that the presence of cold and widespread mechanical hyperalgesia in conjunction with the MRI findings of muscular fatty infiltrate in the upper cervical musculature could be reflective of a peripheral nerve injury in the cervical region [8,18,21,35,36,63] and could explain the widespread sensory findings in this cohort. The presence of these sensory features in conjunction with the temporal development and magnitude of fatty infiltrate needs to be investigated in a prospective, longitudinal study with a more heterogeneous population to better identify a possible neuropathic [3,24] element in at least some patients who transition to chronicity.…”

Role of Skeletal Muscle MRI inPeripheral Nerve Disorders

“…Beside the time sensitivity, detection sensitivity is also important when considering radiological-physiological correlations. McDonald and colleagues directly compared the findings of MRI and needle EMG in 90 patients with peripheral nerve injury or radiculopathy of one to four months duration (McDonald et al, 2000). The results of the two methods matched anatomically in 49 subjects, i.e.…”

“…Animal experiments have also been conducted, in which muscle MRI was examined after peripheral nerve transection. MRI has several distinct advantages over needle electromyography (EMG), including noninvasiveness, accessibility to deep muscles and interexaminer reliability Bendszus et al, 2003;McDonald et al, 2000). MRI is particularly useful as needle EMG is difficult to perform on children or patients on anticoagulation.…”