Neuromuscular ultrasound is a diagnostic imaging technique that utilizes high-frequency sound waves to create real-time, high-resolution images of muscles, nerves, and their interactions. This technology has been gaining popularity to enhance the diagnosis of neuromuscular disorders, validate treatment plans, monitor treatment progress, and guide interventions.
While it should not be viewed as a replacement for electromyography and Nerve Conduction Studies (NCS), neuromuscular ultrasound is a cost-effective, noninvasive way for clinicians to assess neuromuscular disorders. The technology has been proven to augment the evaluation of myopathies and neuropathies¹, enhance diagnoses² and help monitor disease progression. Neuromuscular ultrasound has even become a standard tool for the assessment of peripheral nerve and muscle diseases³ such as amyotrophic lateral sclerosis (ALS), peripheral neuropathy, and muscular dystrophy.
Technological advancements in high-resolution ultrasound imaging over the past two decades have contributed to the rising use of ultrasound systems within neurology practices. Neurologists and other clinicians increasingly rely on neuromuscular ultrasound to expand their testing portfolio, assist with needle insertions and injections, and confirm treatment plans. The additional insights provided by neuromuscular ultrasound come without exposing patients to unnecessary radiation or discomfort.
Neuromuscular ultrasound works well with electromyography EMG and nerve conduction studies (NCS) to provide more comprehensive assessments of the patient’s condition. By providing real-time, high-resolution images of muscles, nerves, and their interactions, neuromuscular ultrasound often helps identify the root cause of patient symptoms. In motor neuron diseases like ALS, for example, ultrasound imaging technology helps assess muscle denervation.4
A strong attribute of neuromuscular ultrasound is its capacity for real-time visualization. In contrast to static images, which offer only a snapshot in time, this technology provides dynamic insights into muscle and nerve function. Neurologists and other specialists can observe real-time changes, enabling them to make informed decisions on the spot. Such imaging can prove invaluable when diagnosing conditions that manifest in movement abnormalities, or when assessing muscle and nerve responses during various tasks.
Neuromuscular Ultrasound is the ideal adjunctive modality that can provide invaluable anatomic correlation to EMG electrophysiology.
Jeffrey A. Strakowski, MD
Ohio State University
Neuromuscular disorders can manifest in various ways, often with subtle or early-stage symptoms. Neuromuscular ultrasound excels in identifying structural abnormalities, even before they become clinically significant. It is commonly used for diagnosing nerve entrapment syndromes, including carpal tunnel syndrome, which accounts for 90% of all neuropathies.5 High-frequency ultrasound technology can help detect changes in nerve mobility, vascular changes caused by local inflammation and/or injuries, and other indicators of entrapment neuropathies.
Carpal tunnel and other nerve entrapment syndromes often occur in anatomically complex regions where nerves traverse tight passages or tunnels. Neuromuscular ultrasound provides clear visualization of these anatomical structures, and thus, greater insight regarding the exact location and potential causes of nerve compression. Its ability to dynamically reveal conditions is particularly valuable, since nerve entrapment symptoms are often aggravated by certain actions or positions, which can be observed during the actual ultrasound test.
High-resolution ultrasound has also proven effective in differentiating between nerve entrapment syndromes and other conditions such as arthritis, radiculopathies, and certain muscle disorders.6
Neuropathies and radiculopathies are two categories of neurological disorders that affect the peripheral nervous system. Neuropathies affect peripheral nerves, which extend from the spinal cord to various parts of the body; the disorder often manifests as numbness, tingling, weakness, and pain in the distribution of the affected nerves. Radiculopathies, on the other hand, involve the compression, inflammation, or irritation of nerve roots as they exit the spinal cord. They often present with pain, weakness, and sensory changes in specific body areas, depending on the affected nerve root.
For both conditions, neuromuscular ultrasound is particularly useful, for it can pinpoint the exact location of nerve compression and/or injury. This includes identifying subtle structural abnormalities and other nerve pathologies7, along with anatomical changes related to nerve enlargement, vascularity, and other symptoms. In cases of radiculopathies, the technology can assist surgeons in identifying the precise level of nerve root involvement.
Neuromuscular ultrasound’s dynamic imaging capabilities are invaluable for monitoring treatment progress. The technology plays a critical role in post-operative assessments, offering real-time insights into healing processes, graft integration, and potential complications. It has proved crucial in the detection of post-surgical nerve injuries8, helping to overcome some of the limitations of EMG and NCS in assessing nerve damage.
With neuromuscular ultrasound, neurologists and other specialists can track changes in nerve size, muscle mobility, or compression over time. The ability to track changes in muscle and nerve structures as treatment progresses ensures that plans will be adjusted as needed, optimizing recovery and enhancing patient outcomes. The technology also informs treatment plans as physical therapy progresses, providing ongoing visual feedback on muscle and tendon rehabilitation.
Neuromuscular disorders often present unique needs for techniques that are noninvasive, portable, and accessible. Neuromuscular ultrasound addresses these needs while offering a less costly option for clinical practices and providers. By offering more accuracy for clinicians when administering injections or conducting needle insertions, neuromuscular ultrasound also reduces physical and emotional impacts on patients.
In short, there are many benefits of neuromuscular ultrasound, not the least of which include:
Neuromuscular ultrasound is a valuable tool in diagnosing, monitoring, and treating many neuromuscular conditions. As a cost-effective technology that helps identify neuromuscular pathologies, it enhances clinician accuracy and patient comfort and offers an excellent complement to EMG and NCS.
1. Zaidman CM, van Alfen N. Ultrasound in the Assessment of Myopathic Disorders. J Clin Neurophysiol. 2016 Apr;33(2):103-11. doi: 10.1097/WNP.0000000000000245. PMID: 27035250.
2. Mah, J., & Van Alfen, N. (2018). Neuromuscular Ultrasound: Clinical Applications and Diagnostic Values. Canadian Journal of Neurological Sciences, 45(6), 605-619. doi:10.1017/cjn.2018.314
3. Hannaford A, Vucic S, Kiernan MC, Simon NG. Review Article “Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date”. Int J Gen Med. 2021 Aug 16;14:4579-4604. doi: 10.2147/IJGM.S295851. PMID: 34429642; PMCID: PMC8378935.
4 Barnes SL, Simon NG. Clinical and research applications of neuromuscular ultrasound in amyotrophic lateral sclerosis. Degener Neurol Neuromuscul Dis. 2019 Jul 16;9:89-102. doi: 10.2147/DNND.S215318. PMID: 31406480; PMCID: PMC6642653.
Sevy JO, Varacallo M. Carpal Tunnel Syndrome. [Updated 2022 Sep 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448179/
5.Walker FO, Cartwright MS, Alter KE, Visser LH, Hobson-Webb LD, Padua L, Strakowski JA, Preston DC, Boon AJ, Axer H, van Alfen N, Tawfik EA, Wilder-Smith E, Yoon JS, Kim BJ, Breiner A, Bland JDP, Grimm A, Zaidman CM. Indications for neuromuscular ultrasound: Expert opinion and review of the literature. Clin Neurophysiol. 2018 Dec;129(12):2658-2679. doi: 10.1016/j.clinph.2018.09.013. Epub 2018 Sep 25. PMID: 30309740.
6. Yoon JS, Walker FO, Cartwright MS. Ulnar neuropathy with normal electrodiagnosis and abnormal nerve ultrasound. Arch Phys Med Rehabil. 2010 Feb;91(2):318-20. doi: 10.1016/j.apmr.2009.10.010. PMID: 20159139; PMCID: PMC2892824.
7. Huang J, Li J, Wang H. The Principles and Procedures of Ultrasound-guided Anesthesia Techniques. Cureus. 2018 Jul 13;10(7):e2980. doi: 10.7759/cureus.2980. PMID: 30237941; PMCID: PMC6141058.
8. The Benefits of Neuromuscular Ultrasound Immediately After Surgery: A Case Example (4870) Laura Danielson, David Preston Neurology Apr 2020, 94 (15 Supplement) 4870;
9. Mercuri M, Sheth T, Natarajan MK. Radiation exposure from medical imaging: a silent harm? CMAJ. 2011 Mar 8;183(4):413-4. doi: 10.1503/cmaj.101885. Epub 2011 Feb 7. PMID: 21324851; PMCID: PMC3050942.
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